root/drivers/block/rbd.c

DEFINITIONS

1. atomic_inc_return_safe
2. atomic_dec_return_safe
3. rbd_dev_id_to_minor
4. minor_to_rbd_dev_id
5. __rbd_is_lock_owner
6. rbd_is_lock_owner
7. supported_features_show
8. rbd_bus_is_visible
9. rbd_root_dev_release
10. __printf
11. pending_result_dec
12. rbd_open
13. rbd_release
14. rbd_ioctl_set_ro
15. rbd_ioctl
16. rbd_compat_ioctl
17. rbd_client_create
18. __rbd_get_client
19. rbd_client_find
20. parse_rbd_opts_token
21. obj_op_name
22. rbd_client_release
23. rbd_put_client
24. rbd_get_client
25. rbd_image_format_valid
26. rbd_dev_ondisk_valid
27. rbd_obj_bytes
28. rbd_init_layout
29. rbd_header_from_disk
30. _rbd_dev_v1_snap_name
31. snapid_compare_reverse
32. rbd_dev_snap_index
33. rbd_dev_v1_snap_name
34. rbd_snap_name
35. rbd_snap_size
36. rbd_snap_features
37. rbd_dev_mapping_set
38. rbd_dev_mapping_clear
39. zero_bvec
40. zero_bios
41. zero_bvecs
42. rbd_obj_zero_range
43. rbd_obj_request_put
44. rbd_img_request_put
45. rbd_img_obj_request_add
46. rbd_img_obj_request_del
47. rbd_osd_submit
48. img_request_layered_set
49. img_request_layered_clear
50. img_request_layered_test
51. rbd_obj_is_entire
52. rbd_obj_is_tail
53. rbd_obj_copyup_enabled
54. rbd_obj_img_extents_bytes
55. rbd_img_is_write
56. rbd_osd_req_callback
57. rbd_osd_format_read
58. rbd_osd_format_write
59. __rbd_obj_add_osd_request
60. rbd_obj_add_osd_request
61. rbd_obj_request_create
62. rbd_obj_request_destroy
63. rbd_dev_unparent
64. rbd_dev_parent_put
65. rbd_dev_parent_get
66. rbd_img_request_create
67. rbd_img_request_destroy
68. __rbd_object_map_index
69. __rbd_object_map_get
70. __rbd_object_map_set
71. rbd_object_map_get
72. use_object_map
73. rbd_object_map_may_exist
74. rbd_object_map_name
75. rbd_object_map_lock
76. rbd_object_map_unlock
77. decode_object_map_header
78. __rbd_object_map_load
79. rbd_object_map_free
80. rbd_object_map_load
81. rbd_object_map_open
82. rbd_object_map_close
83. rbd_object_map_update_finish
84. rbd_object_map_callback
85. update_needed
86. rbd_cls_object_map_update
87. rbd_object_map_update
88. prune_extents
89. rbd_obj_calc_img_extents
90. rbd_osd_setup_data
91. rbd_osd_setup_stat
92. rbd_osd_setup_copyup
93. rbd_obj_init_read
94. __rbd_osd_setup_write_ops
95. rbd_obj_init_write
96. truncate_or_zero_opcode
97. __rbd_osd_setup_discard_ops
98. rbd_obj_init_discard
99. __rbd_osd_setup_zeroout_ops
100. rbd_obj_init_zeroout
101. count_write_ops
102. rbd_osd_setup_write_ops
103. __rbd_img_fill_request
104. alloc_object_extent
105. rbd_layout_is_fancy
106. rbd_img_fill_request_nocopy
107. rbd_img_fill_request
108. rbd_img_fill_nodata
109. set_bio_pos
110. count_bio_bvecs
111. copy_bio_bvecs
112. __rbd_img_fill_from_bio
113. rbd_img_fill_from_bio
114. set_bvec_pos
115. count_bvecs
116. copy_bvecs
117. __rbd_img_fill_from_bvecs
118. rbd_img_fill_from_bvecs
119. rbd_img_handle_request_work
120. rbd_img_schedule
121. rbd_obj_may_exist
122. rbd_obj_read_object
123. rbd_obj_read_from_parent
124. rbd_obj_advance_read
125. rbd_obj_write_is_noop
126. rbd_obj_write_pre_object_map
127. rbd_obj_write_object
128. is_zero_bvecs
129. rbd_obj_copyup_empty_snapc
130. rbd_obj_copyup_current_snapc
131. setup_copyup_bvecs
132. rbd_obj_copyup_read_parent
133. rbd_obj_copyup_object_maps
134. rbd_obj_copyup_write_object
135. rbd_obj_advance_copyup
136. rbd_obj_write_post_object_map
137. rbd_obj_advance_write
138. __rbd_obj_handle_request
139. rbd_obj_handle_request
140. need_exclusive_lock
141. rbd_lock_add_request
142. rbd_lock_del_request
143. rbd_img_exclusive_lock
144. rbd_img_object_requests
145. rbd_img_advance
146. __rbd_img_handle_request
147. rbd_img_handle_request
148. rbd_cid_equal
149. rbd_get_cid
150. rbd_set_owner_cid
151. format_lock_cookie
152. __rbd_lock
153. rbd_lock
154. rbd_unlock
155. __rbd_notify_op_lock
156. rbd_notify_op_lock
157. rbd_notify_acquired_lock
158. rbd_notify_released_lock
159. rbd_request_lock
160. wake_lock_waiters
161. get_lock_owner_info
162. find_watcher
163. rbd_try_lock
164. rbd_post_acquire_action
165. rbd_try_acquire_lock
166. rbd_acquire_lock
167. rbd_quiesce_lock
168. rbd_pre_release_action
169. __rbd_release_lock
170. rbd_release_lock
171. rbd_release_lock_work
172. maybe_kick_acquire
173. rbd_handle_acquired_lock
174. rbd_handle_released_lock
175. rbd_handle_request_lock
176. __rbd_acknowledge_notify
177. rbd_acknowledge_notify
178. rbd_acknowledge_notify_result
179. rbd_watch_cb
180. rbd_watch_errcb
181. __rbd_register_watch
182. __rbd_unregister_watch
183. rbd_register_watch
184. cancel_tasks_sync
185. rbd_unregister_watch
186. rbd_reacquire_lock
187. rbd_reregister_watch
188. rbd_obj_method_sync
189. rbd_queue_workfn
190. rbd_queue_rq
191. rbd_free_disk
192. rbd_obj_read_sync
193. rbd_dev_v1_header_info
194. rbd_exists_validate
195. rbd_dev_update_size
196. rbd_dev_refresh
197. rbd_init_request
198. rbd_init_disk
199. dev_to_rbd_dev
200. rbd_size_show
201. rbd_features_show
202. rbd_major_show
203. rbd_minor_show
204. rbd_client_addr_show
205. rbd_client_id_show
206. rbd_cluster_fsid_show
207. rbd_config_info_show
208. rbd_pool_show
209. rbd_pool_id_show
210. rbd_pool_ns_show
211. rbd_name_show
212. rbd_image_id_show
213. rbd_snap_show
214. rbd_snap_id_show
215. rbd_parent_show
216. rbd_image_refresh
217. rbd_spec_get
218. rbd_spec_put
219. rbd_spec_alloc
220. rbd_spec_free
221. rbd_dev_free
222. rbd_dev_release
223. __rbd_dev_create
224. rbd_dev_create
225. rbd_dev_destroy
226. _rbd_dev_v2_snap_size
227. rbd_dev_v2_image_size
228. rbd_dev_v2_object_prefix
229. _rbd_dev_v2_snap_features
230. rbd_dev_v2_features
231. rbd_dev_v2_get_flags
232. decode_parent_image_spec
233. __get_parent_info
234. __get_parent_info_legacy
235. get_parent_info
236. rbd_dev_v2_parent_info
237. rbd_dev_v2_striping_info
238. rbd_dev_v2_data_pool
239. rbd_dev_image_name
240. rbd_v1_snap_id_by_name
241. rbd_v2_snap_id_by_name
242. rbd_snap_id_by_name
243. rbd_spec_fill_snap_id
244. rbd_spec_fill_names
245. rbd_dev_v2_snap_context
246. rbd_dev_v2_snap_name
247. rbd_dev_v2_header_info
248. rbd_dev_header_info
249. next_token
250. dup_token
251. rbd_add_parse_args
252. rbd_dev_image_unlock
253. rbd_add_acquire_lock
254. rbd_dev_image_id
255. rbd_dev_unprobe
256. rbd_dev_v2_header_onetime
257. rbd_dev_probe_parent
258. rbd_dev_device_release
259. rbd_dev_device_setup
260. rbd_dev_header_name
261. rbd_dev_image_release
262. rbd_dev_image_probe
263. do_rbd_add
264. add_store
265. add_single_major_store
266. rbd_dev_remove_parent
267. do_rbd_remove
268. remove_store
269. remove_single_major_store
270. rbd_sysfs_init
271. rbd_sysfs_cleanup
272. rbd_slab_init
273. rbd_slab_exit
274. rbd_init
275. rbd_exit

   1 
   2 /*
   3    rbd.c -- Export ceph rados objects as a Linux block device
   4 
   5 
   6    based on drivers/block/osdblk.c:
   7 
   8    Copyright 2009 Red Hat, Inc.
   9 
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation.
  13 
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18 
  19    You should have received a copy of the GNU General Public License
  20    along with this program; see the file COPYING.  If not, write to
  21    the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  22 
  23 
  24 
  25    For usage instructions, please refer to:
  26 
  27                  Documentation/ABI/testing/sysfs-bus-rbd
  28 
  29  */
  30 
  31 #include <linux/ceph/libceph.h>
  32 #include <linux/ceph/osd_client.h>
  33 #include <linux/ceph/mon_client.h>
  34 #include <linux/ceph/cls_lock_client.h>
  35 #include <linux/ceph/striper.h>
  36 #include <linux/ceph/decode.h>
  37 #include <linux/parser.h>
  38 #include <linux/bsearch.h>
  39 
  40 #include <linux/kernel.h>
  41 #include <linux/device.h>
  42 #include <linux/module.h>
  43 #include <linux/blk-mq.h>
  44 #include <linux/fs.h>
  45 #include <linux/blkdev.h>
  46 #include <linux/slab.h>
  47 #include <linux/idr.h>
  48 #include <linux/workqueue.h>
  49 
  50 #include "rbd_types.h"
  51 
  52 #define RBD_DEBUG       /* Activate rbd_assert() calls */
  53 
  54 /*
  55  * Increment the given counter and return its updated value.
  56  * If the counter is already 0 it will not be incremented.
  57  * If the counter is already at its maximum value returns
  58  * -EINVAL without updating it.
  59  */
  60 static int atomic_inc_return_safe(atomic_t *v)
  61 {
  62         unsigned int counter;
  63 
  64         counter = (unsigned int)atomic_fetch_add_unless(v, 1, 0);
  65         if (counter <= (unsigned int)INT_MAX)
  66                 return (int)counter;
  67 
  68         atomic_dec(v);
  69 
  70         return -EINVAL;
  71 }
  72 
  73 /* Decrement the counter.  Return the resulting value, or -EINVAL */
  74 static int atomic_dec_return_safe(atomic_t *v)
  75 {
  76         int counter;
  77 
  78         counter = atomic_dec_return(v);
  79         if (counter >= 0)
  80                 return counter;
  81 
  82         atomic_inc(v);
  83 
  84         return -EINVAL;
  85 }
  86 
  87 #define RBD_DRV_NAME "rbd"
  88 
  89 #define RBD_MINORS_PER_MAJOR            256
  90 #define RBD_SINGLE_MAJOR_PART_SHIFT     4
  91 
  92 #define RBD_MAX_PARENT_CHAIN_LEN        16
  93 
  94 #define RBD_SNAP_DEV_NAME_PREFIX        "snap_"
  95 #define RBD_MAX_SNAP_NAME_LEN   \
  96                         (NAME_MAX - (sizeof (RBD_SNAP_DEV_NAME_PREFIX) - 1))
  97 
  98 #define RBD_MAX_SNAP_COUNT      510     /* allows max snapc to fit in 4KB */
  99 
 100 #define RBD_SNAP_HEAD_NAME      "-"
 101 
 102 #define BAD_SNAP_INDEX  U32_MAX         /* invalid index into snap array */
 103 
 104 /* This allows a single page to hold an image name sent by OSD */
 105 #define RBD_IMAGE_NAME_LEN_MAX  (PAGE_SIZE - sizeof (__le32) - 1)
 106 #define RBD_IMAGE_ID_LEN_MAX    64
 107 
 108 #define RBD_OBJ_PREFIX_LEN_MAX  64
 109 
 110 #define RBD_NOTIFY_TIMEOUT      5       /* seconds */
 111 #define RBD_RETRY_DELAY         msecs_to_jiffies(1000)
 112 
 113 /* Feature bits */
 114 
 115 #define RBD_FEATURE_LAYERING            (1ULL<<0)
 116 #define RBD_FEATURE_STRIPINGV2          (1ULL<<1)
 117 #define RBD_FEATURE_EXCLUSIVE_LOCK      (1ULL<<2)
 118 #define RBD_FEATURE_OBJECT_MAP          (1ULL<<3)
 119 #define RBD_FEATURE_FAST_DIFF           (1ULL<<4)
 120 #define RBD_FEATURE_DEEP_FLATTEN        (1ULL<<5)
 121 #define RBD_FEATURE_DATA_POOL           (1ULL<<7)
 122 #define RBD_FEATURE_OPERATIONS          (1ULL<<8)
 123 
 124 #define RBD_FEATURES_ALL        (RBD_FEATURE_LAYERING |         \
 125                                  RBD_FEATURE_STRIPINGV2 |       \
 126                                  RBD_FEATURE_EXCLUSIVE_LOCK |   \
 127                                  RBD_FEATURE_OBJECT_MAP |       \
 128                                  RBD_FEATURE_FAST_DIFF |        \
 129                                  RBD_FEATURE_DEEP_FLATTEN |     \
 130                                  RBD_FEATURE_DATA_POOL |        \
 131                                  RBD_FEATURE_OPERATIONS)
 132 
 133 /* Features supported by this (client software) implementation. */
 134 
 135 #define RBD_FEATURES_SUPPORTED  (RBD_FEATURES_ALL)
 136 
 137 /*
 138  * An RBD device name will be "rbd#", where the "rbd" comes from
 139  * RBD_DRV_NAME above, and # is a unique integer identifier.
 140  */
 141 #define DEV_NAME_LEN            32
 142 
 143 /*
 144  * block device image metadata (in-memory version)
 145  */
 146 struct rbd_image_header {
 147         /* These six fields never change for a given rbd image */
 148         char *object_prefix;
 149         __u8 obj_order;
 150         u64 stripe_unit;
 151         u64 stripe_count;
 152         s64 data_pool_id;
 153         u64 features;           /* Might be changeable someday? */
 154 
 155         /* The remaining fields need to be updated occasionally */
 156         u64 image_size;
 157         struct ceph_snap_context *snapc;
 158         char *snap_names;       /* format 1 only */
 159         u64 *snap_sizes;        /* format 1 only */
 160 };
 161 
 162 /*
 163  * An rbd image specification.
 164  *
 165  * The tuple (pool_id, image_id, snap_id) is sufficient to uniquely
 166  * identify an image.  Each rbd_dev structure includes a pointer to
 167  * an rbd_spec structure that encapsulates this identity.
 168  *
 169  * Each of the id's in an rbd_spec has an associated name.  For a
 170  * user-mapped image, the names are supplied and the id's associated
 171  * with them are looked up.  For a layered image, a parent image is
 172  * defined by the tuple, and the names are looked up.
 173  *
 174  * An rbd_dev structure contains a parent_spec pointer which is
 175  * non-null if the image it represents is a child in a layered
 176  * image.  This pointer will refer to the rbd_spec structure used
 177  * by the parent rbd_dev for its own identity (i.e., the structure
 178  * is shared between the parent and child).
 179  *
 180  * Since these structures are populated once, during the discovery
 181  * phase of image construction, they are effectively immutable so
 182  * we make no effort to synchronize access to them.
 183  *
 184  * Note that code herein does not assume the image name is known (it
 185  * could be a null pointer).
 186  */
 187 struct rbd_spec {
 188         u64             pool_id;
 189         const char      *pool_name;
 190         const char      *pool_ns;       /* NULL if default, never "" */
 191 
 192         const char      *image_id;
 193         const char      *image_name;
 194 
 195         u64             snap_id;
 196         const char      *snap_name;
 197 
 198         struct kref     kref;
 199 };
 200 
 201 /*
 202  * an instance of the client.  multiple devices may share an rbd client.
 203  */
 204 struct rbd_client {
 205         struct ceph_client      *client;
 206         struct kref             kref;
 207         struct list_head        node;
 208 };
 209 
 210 struct pending_result {
 211         int                     result;         /* first nonzero result */
 212         int                     num_pending;
 213 };
 214 
 215 struct rbd_img_request;
 216 
 217 enum obj_request_type {
 218         OBJ_REQUEST_NODATA = 1,
 219         OBJ_REQUEST_BIO,        /* pointer into provided bio (list) */
 220         OBJ_REQUEST_BVECS,      /* pointer into provided bio_vec array */
 221         OBJ_REQUEST_OWN_BVECS,  /* private bio_vec array, doesn't own pages */
 222 };
 223 
 224 enum obj_operation_type {
 225         OBJ_OP_READ = 1,
 226         OBJ_OP_WRITE,
 227         OBJ_OP_DISCARD,
 228         OBJ_OP_ZEROOUT,
 229 };
 230 
 231 #define RBD_OBJ_FLAG_DELETION                   (1U << 0)
 232 #define RBD_OBJ_FLAG_COPYUP_ENABLED             (1U << 1)
 233 #define RBD_OBJ_FLAG_COPYUP_ZEROS               (1U << 2)
 234 #define RBD_OBJ_FLAG_MAY_EXIST                  (1U << 3)
 235 #define RBD_OBJ_FLAG_NOOP_FOR_NONEXISTENT       (1U << 4)
 236 
 237 enum rbd_obj_read_state {
 238         RBD_OBJ_READ_START = 1,
 239         RBD_OBJ_READ_OBJECT,
 240         RBD_OBJ_READ_PARENT,
 241 };
 242 
 243 /*
 244  * Writes go through the following state machine to deal with
 245  * layering:
 246  *
 247  *            . . . . . RBD_OBJ_WRITE_GUARD. . . . . . . . . . . . . .
 248  *            .                 |                                    .
 249  *            .                 v                                    .
 250  *            .    RBD_OBJ_WRITE_READ_FROM_PARENT. . .               .
 251  *            .                 |                    .               .
 252  *            .                 v                    v (deep-copyup  .
 253  *    (image  .   RBD_OBJ_WRITE_COPYUP_EMPTY_SNAPC   .  not needed)  .
 254  * flattened) v                 |                    .               .
 255  *            .                 v                    .               .
 256  *            . . . .RBD_OBJ_WRITE_COPYUP_OPS. . . . .      (copyup  .
 257  *                              |                        not needed) v
 258  *                              v                                    .
 259  *                            done . . . . . . . . . . . . . . . . . .
 260  *                              ^
 261  *                              |
 262  *                     RBD_OBJ_WRITE_FLAT
 263  *
 264  * Writes start in RBD_OBJ_WRITE_GUARD or _FLAT, depending on whether
 265  * assert_exists guard is needed or not (in some cases it's not needed
 266  * even if there is a parent).
 267  */
 268 enum rbd_obj_write_state {
 269         RBD_OBJ_WRITE_START = 1,
 270         RBD_OBJ_WRITE_PRE_OBJECT_MAP,
 271         RBD_OBJ_WRITE_OBJECT,
 272         __RBD_OBJ_WRITE_COPYUP,
 273         RBD_OBJ_WRITE_COPYUP,
 274         RBD_OBJ_WRITE_POST_OBJECT_MAP,
 275 };
 276 
 277 enum rbd_obj_copyup_state {
 278         RBD_OBJ_COPYUP_START = 1,
 279         RBD_OBJ_COPYUP_READ_PARENT,
 280         __RBD_OBJ_COPYUP_OBJECT_MAPS,
 281         RBD_OBJ_COPYUP_OBJECT_MAPS,
 282         __RBD_OBJ_COPYUP_WRITE_OBJECT,
 283         RBD_OBJ_COPYUP_WRITE_OBJECT,
 284 };
 285 
 286 struct rbd_obj_request {
 287         struct ceph_object_extent ex;
 288         unsigned int            flags;  /* RBD_OBJ_FLAG_* */
 289         union {
 290                 enum rbd_obj_read_state  read_state;    /* for reads */
 291                 enum rbd_obj_write_state write_state;   /* for writes */
 292         };
 293 
 294         struct rbd_img_request  *img_request;
 295         struct ceph_file_extent *img_extents;
 296         u32                     num_img_extents;
 297 
 298         union {
 299                 struct ceph_bio_iter    bio_pos;
 300                 struct {
 301                         struct ceph_bvec_iter   bvec_pos;
 302                         u32                     bvec_count;
 303                         u32                     bvec_idx;
 304                 };
 305         };
 306 
 307         enum rbd_obj_copyup_state copyup_state;
 308         struct bio_vec          *copyup_bvecs;
 309         u32                     copyup_bvec_count;
 310 
 311         struct list_head        osd_reqs;       /* w/ r_private_item */
 312 
 313         struct mutex            state_mutex;
 314         struct pending_result   pending;
 315         struct kref             kref;
 316 };
 317 
 318 enum img_req_flags {
 319         IMG_REQ_CHILD,          /* initiator: block = 0, child image = 1 */
 320         IMG_REQ_LAYERED,        /* ENOENT handling: normal = 0, layered = 1 */
 321 };
 322 
 323 enum rbd_img_state {
 324         RBD_IMG_START = 1,
 325         RBD_IMG_EXCLUSIVE_LOCK,
 326         __RBD_IMG_OBJECT_REQUESTS,
 327         RBD_IMG_OBJECT_REQUESTS,
 328 };
 329 
 330 struct rbd_img_request {
 331         struct rbd_device       *rbd_dev;
 332         enum obj_operation_type op_type;
 333         enum obj_request_type   data_type;
 334         unsigned long           flags;
 335         enum rbd_img_state      state;
 336         union {
 337                 u64                     snap_id;        /* for reads */
 338                 struct ceph_snap_context *snapc;        /* for writes */
 339         };
 340         union {
 341                 struct request          *rq;            /* block request */
 342                 struct rbd_obj_request  *obj_request;   /* obj req initiator */
 343         };
 344 
 345         struct list_head        lock_item;
 346         struct list_head        object_extents; /* obj_req.ex structs */
 347 
 348         struct mutex            state_mutex;
 349         struct pending_result   pending;
 350         struct work_struct      work;
 351         int                     work_result;
 352         struct kref             kref;
 353 };
 354 
 355 #define for_each_obj_request(ireq, oreq) \
 356         list_for_each_entry(oreq, &(ireq)->object_extents, ex.oe_item)
 357 #define for_each_obj_request_safe(ireq, oreq, n) \
 358         list_for_each_entry_safe(oreq, n, &(ireq)->object_extents, ex.oe_item)
 359 
 360 enum rbd_watch_state {
 361         RBD_WATCH_STATE_UNREGISTERED,
 362         RBD_WATCH_STATE_REGISTERED,
 363         RBD_WATCH_STATE_ERROR,
 364 };
 365 
 366 enum rbd_lock_state {
 367         RBD_LOCK_STATE_UNLOCKED,
 368         RBD_LOCK_STATE_LOCKED,
 369         RBD_LOCK_STATE_RELEASING,
 370 };
 371 
 372 /* WatchNotify::ClientId */
 373 struct rbd_client_id {
 374         u64 gid;
 375         u64 handle;
 376 };
 377 
 378 struct rbd_mapping {
 379         u64                     size;
 380         u64                     features;
 381 };
 382 
 383 /*
 384  * a single device
 385  */
 386 struct rbd_device {
 387         int                     dev_id;         /* blkdev unique id */
 388 
 389         int                     major;          /* blkdev assigned major */
 390         int                     minor;
 391         struct gendisk          *disk;          /* blkdev's gendisk and rq */
 392 
 393         u32                     image_format;   /* Either 1 or 2 */
 394         struct rbd_client       *rbd_client;
 395 
 396         char                    name[DEV_NAME_LEN]; /* blkdev name, e.g. rbd3 */
 397 
 398         spinlock_t              lock;           /* queue, flags, open_count */
 399 
 400         struct rbd_image_header header;
 401         unsigned long           flags;          /* possibly lock protected */
 402         struct rbd_spec         *spec;
 403         struct rbd_options      *opts;
 404         char                    *config_info;   /* add{,_single_major} string */
 405 
 406         struct ceph_object_id   header_oid;
 407         struct ceph_object_locator header_oloc;
 408 
 409         struct ceph_file_layout layout;         /* used for all rbd requests */
 410 
 411         struct mutex            watch_mutex;
 412         enum rbd_watch_state    watch_state;
 413         struct ceph_osd_linger_request *watch_handle;
 414         u64                     watch_cookie;
 415         struct delayed_work     watch_dwork;
 416 
 417         struct rw_semaphore     lock_rwsem;
 418         enum rbd_lock_state     lock_state;
 419         char                    lock_cookie[32];
 420         struct rbd_client_id    owner_cid;
 421         struct work_struct      acquired_lock_work;
 422         struct work_struct      released_lock_work;
 423         struct delayed_work     lock_dwork;
 424         struct work_struct      unlock_work;
 425         spinlock_t              lock_lists_lock;
 426         struct list_head        acquiring_list;
 427         struct list_head        running_list;
 428         struct completion       acquire_wait;
 429         int                     acquire_err;
 430         struct completion       releasing_wait;
 431 
 432         spinlock_t              object_map_lock;
 433         u8                      *object_map;
 434         u64                     object_map_size;        /* in objects */
 435         u64                     object_map_flags;
 436 
 437         struct workqueue_struct *task_wq;
 438 
 439         struct rbd_spec         *parent_spec;
 440         u64                     parent_overlap;
 441         atomic_t                parent_ref;
 442         struct rbd_device       *parent;
 443 
 444         /* Block layer tags. */
 445         struct blk_mq_tag_set   tag_set;
 446 
 447         /* protects updating the header */
 448         struct rw_semaphore     header_rwsem;
 449 
 450         struct rbd_mapping      mapping;
 451 
 452         struct list_head        node;
 453 
 454         /* sysfs related */
 455         struct device           dev;
 456         unsigned long           open_count;     /* protected by lock */
 457 };
 458 
 459 /*
 460  * Flag bits for rbd_dev->flags:
 461  * - REMOVING (which is coupled with rbd_dev->open_count) is protected
 462  *   by rbd_dev->lock
 463  */
 464 enum rbd_dev_flags {
 465         RBD_DEV_FLAG_EXISTS,    /* mapped snapshot has not been deleted */
 466         RBD_DEV_FLAG_REMOVING,  /* this mapping is being removed */
 467 };
 468 
 469 static DEFINE_MUTEX(client_mutex);      /* Serialize client creation */
 470 
 471 static LIST_HEAD(rbd_dev_list);    /* devices */
 472 static DEFINE_SPINLOCK(rbd_dev_list_lock);
 473 
 474 static LIST_HEAD(rbd_client_list);              /* clients */
 475 static DEFINE_SPINLOCK(rbd_client_list_lock);
 476 
 477 /* Slab caches for frequently-allocated structures */
 478 
 479 static struct kmem_cache        *rbd_img_request_cache;
 480 static struct kmem_cache        *rbd_obj_request_cache;
 481 
 482 static int rbd_major;
 483 static DEFINE_IDA(rbd_dev_id_ida);
 484 
 485 static struct workqueue_struct *rbd_wq;
 486 
 487 static struct ceph_snap_context rbd_empty_snapc = {
 488         .nref = REFCOUNT_INIT(1),
 489 };
 490 
 491 /*
 492  * single-major requires >= 0.75 version of userspace rbd utility.
 493  */
 494 static bool single_major = true;
 495 module_param(single_major, bool, 0444);
 496 MODULE_PARM_DESC(single_major, "Use a single major number for all rbd devices (default: true)");
 497 
 498 static ssize_t add_store(struct bus_type *bus, const char *buf, size_t count);
 499 static ssize_t remove_store(struct bus_type *bus, const char *buf,
 500                             size_t count);
 501 static ssize_t add_single_major_store(struct bus_type *bus, const char *buf,
 502                                       size_t count);
 503 static ssize_t remove_single_major_store(struct bus_type *bus, const char *buf,
 504                                          size_t count);
 505 static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth);
 506 
 507 static int rbd_dev_id_to_minor(int dev_id)
 508 {
 509         return dev_id << RBD_SINGLE_MAJOR_PART_SHIFT;
 510 }
 511 
 512 static int minor_to_rbd_dev_id(int minor)
 513 {
 514         return minor >> RBD_SINGLE_MAJOR_PART_SHIFT;
 515 }
 516 
 517 static bool __rbd_is_lock_owner(struct rbd_device *rbd_dev)
 518 {
 519         lockdep_assert_held(&rbd_dev->lock_rwsem);
 520 
 521         return rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED ||
 522                rbd_dev->lock_state == RBD_LOCK_STATE_RELEASING;
 523 }
 524 
 525 static bool rbd_is_lock_owner(struct rbd_device *rbd_dev)
 526 {
 527         bool is_lock_owner;
 528 
 529         down_read(&rbd_dev->lock_rwsem);
 530         is_lock_owner = __rbd_is_lock_owner(rbd_dev);
 531         up_read(&rbd_dev->lock_rwsem);
 532         return is_lock_owner;
 533 }
 534 
 535 static ssize_t supported_features_show(struct bus_type *bus, char *buf)
 536 {
 537         return sprintf(buf, "0x%llx\n", RBD_FEATURES_SUPPORTED);
 538 }
 539 
 540 static BUS_ATTR_WO(add);
 541 static BUS_ATTR_WO(remove);
 542 static BUS_ATTR_WO(add_single_major);
 543 static BUS_ATTR_WO(remove_single_major);
 544 static BUS_ATTR_RO(supported_features);
 545 
 546 static struct attribute *rbd_bus_attrs[] = {
 547         &bus_attr_add.attr,
 548         &bus_attr_remove.attr,
 549         &bus_attr_add_single_major.attr,
 550         &bus_attr_remove_single_major.attr,
 551         &bus_attr_supported_features.attr,
 552         NULL,
 553 };
 554 
 555 static umode_t rbd_bus_is_visible(struct kobject *kobj,
 556                                   struct attribute *attr, int index)
 557 {
 558         if (!single_major &&
 559             (attr == &bus_attr_add_single_major.attr ||
 560              attr == &bus_attr_remove_single_major.attr))
 561                 return 0;
 562 
 563         return attr->mode;
 564 }
 565 
 566 static const struct attribute_group rbd_bus_group = {
 567         .attrs = rbd_bus_attrs,
 568         .is_visible = rbd_bus_is_visible,
 569 };
 570 __ATTRIBUTE_GROUPS(rbd_bus);
 571 
 572 static struct bus_type rbd_bus_type = {
 573         .name           = "rbd",
 574         .bus_groups     = rbd_bus_groups,
 575 };
 576 
 577 static void rbd_root_dev_release(struct device *dev)
 578 {
 579 }
 580 
 581 static struct device rbd_root_dev = {
 582         .init_name =    "rbd",
 583         .release =      rbd_root_dev_release,
 584 };
 585 
 586 static __printf(2, 3)
 587 void rbd_warn(struct rbd_device *rbd_dev, const char *fmt, ...)
 588 {
 589         struct va_format vaf;
 590         va_list args;
 591 
 592         va_start(args, fmt);
 593         vaf.fmt = fmt;
 594         vaf.va = &args;
 595 
 596         if (!rbd_dev)
 597                 printk(KERN_WARNING "%s: %pV\n", RBD_DRV_NAME, &vaf);
 598         else if (rbd_dev->disk)
 599                 printk(KERN_WARNING "%s: %s: %pV\n",
 600                         RBD_DRV_NAME, rbd_dev->disk->disk_name, &vaf);
 601         else if (rbd_dev->spec && rbd_dev->spec->image_name)
 602                 printk(KERN_WARNING "%s: image %s: %pV\n",
 603                         RBD_DRV_NAME, rbd_dev->spec->image_name, &vaf);
 604         else if (rbd_dev->spec && rbd_dev->spec->image_id)
 605                 printk(KERN_WARNING "%s: id %s: %pV\n",
 606                         RBD_DRV_NAME, rbd_dev->spec->image_id, &vaf);
 607         else    /* punt */
 608                 printk(KERN_WARNING "%s: rbd_dev %p: %pV\n",
 609                         RBD_DRV_NAME, rbd_dev, &vaf);
 610         va_end(args);
 611 }
 612 
 613 #ifdef RBD_DEBUG
 614 #define rbd_assert(expr)                                                \
 615                 if (unlikely(!(expr))) {                                \
 616                         printk(KERN_ERR "\nAssertion failure in %s() "  \
 617                                                 "at line %d:\n\n"       \
 618                                         "\trbd_assert(%s);\n\n",        \
 619                                         __func__, __LINE__, #expr);     \
 620                         BUG();                                          \
 621                 }
 622 #else /* !RBD_DEBUG */
 623 #  define rbd_assert(expr)      ((void) 0)
 624 #endif /* !RBD_DEBUG */
 625 
 626 static void rbd_dev_remove_parent(struct rbd_device *rbd_dev);
 627 
 628 static int rbd_dev_refresh(struct rbd_device *rbd_dev);
 629 static int rbd_dev_v2_header_onetime(struct rbd_device *rbd_dev);
 630 static int rbd_dev_header_info(struct rbd_device *rbd_dev);
 631 static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev);
 632 static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev,
 633                                         u64 snap_id);
 634 static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
 635                                 u8 *order, u64 *snap_size);
 636 static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
 637                 u64 *snap_features);
 638 static int rbd_dev_v2_get_flags(struct rbd_device *rbd_dev);
 639 
 640 static void rbd_obj_handle_request(struct rbd_obj_request *obj_req, int result);
 641 static void rbd_img_handle_request(struct rbd_img_request *img_req, int result);
 642 
 643 /*
 644  * Return true if nothing else is pending.
 645  */
 646 static bool pending_result_dec(struct pending_result *pending, int *result)
 647 {
 648         rbd_assert(pending->num_pending > 0);
 649 
 650         if (*result && !pending->result)
 651                 pending->result = *result;
 652         if (--pending->num_pending)
 653                 return false;
 654 
 655         *result = pending->result;
 656         return true;
 657 }
 658 
 659 static int rbd_open(struct block_device *bdev, fmode_t mode)
 660 {
 661         struct rbd_device *rbd_dev = bdev->bd_disk->private_data;
 662         bool removing = false;
 663 
 664         spin_lock_irq(&rbd_dev->lock);
 665         if (test_bit(RBD_DEV_FLAG_REMOVING, &rbd_dev->flags))
 666                 removing = true;
 667         else
 668                 rbd_dev->open_count++;
 669         spin_unlock_irq(&rbd_dev->lock);
 670         if (removing)
 671                 return -ENOENT;
 672 
 673         (void) get_device(&rbd_dev->dev);
 674 
 675         return 0;
 676 }
 677 
 678 static void rbd_release(struct gendisk *disk, fmode_t mode)
 679 {
 680         struct rbd_device *rbd_dev = disk->private_data;
 681         unsigned long open_count_before;
 682 
 683         spin_lock_irq(&rbd_dev->lock);
 684         open_count_before = rbd_dev->open_count--;
 685         spin_unlock_irq(&rbd_dev->lock);
 686         rbd_assert(open_count_before > 0);
 687 
 688         put_device(&rbd_dev->dev);
 689 }
 690 
 691 static int rbd_ioctl_set_ro(struct rbd_device *rbd_dev, unsigned long arg)
 692 {
 693         int ro;
 694 
 695         if (get_user(ro, (int __user *)arg))
 696                 return -EFAULT;
 697 
 698         /* Snapshots can't be marked read-write */
 699         if (rbd_dev->spec->snap_id != CEPH_NOSNAP && !ro)
 700                 return -EROFS;
 701 
 702         /* Let blkdev_roset() handle it */
 703         return -ENOTTY;
 704 }
 705 
 706 static int rbd_ioctl(struct block_device *bdev, fmode_t mode,
 707                         unsigned int cmd, unsigned long arg)
 708 {
 709         struct rbd_device *rbd_dev = bdev->bd_disk->private_data;
 710         int ret;
 711 
 712         switch (cmd) {
 713         case BLKROSET:
 714                 ret = rbd_ioctl_set_ro(rbd_dev, arg);
 715                 break;
 716         default:
 717                 ret = -ENOTTY;
 718         }
 719 
 720         return ret;
 721 }
 722 
 723 #ifdef CONFIG_COMPAT
 724 static int rbd_compat_ioctl(struct block_device *bdev, fmode_t mode,
 725                                 unsigned int cmd, unsigned long arg)
 726 {
 727         return rbd_ioctl(bdev, mode, cmd, arg);
 728 }
 729 #endif /* CONFIG_COMPAT */
 730 
 731 static const struct block_device_operations rbd_bd_ops = {
 732         .owner                  = THIS_MODULE,
 733         .open                   = rbd_open,
 734         .release                = rbd_release,
 735         .ioctl                  = rbd_ioctl,
 736 #ifdef CONFIG_COMPAT
 737         .compat_ioctl           = rbd_compat_ioctl,
 738 #endif
 739 };
 740 
 741 /*
 742  * Initialize an rbd client instance.  Success or not, this function
 743  * consumes ceph_opts.  Caller holds client_mutex.
 744  */
 745 static struct rbd_client *rbd_client_create(struct ceph_options *ceph_opts)
 746 {
 747         struct rbd_client *rbdc;
 748         int ret = -ENOMEM;
 749 
 750         dout("%s:\n", __func__);
 751         rbdc = kmalloc(sizeof(struct rbd_client), GFP_KERNEL);
 752         if (!rbdc)
 753                 goto out_opt;
 754 
 755         kref_init(&rbdc->kref);
 756         INIT_LIST_HEAD(&rbdc->node);
 757 
 758         rbdc->client = ceph_create_client(ceph_opts, rbdc);
 759         if (IS_ERR(rbdc->client))
 760                 goto out_rbdc;
 761         ceph_opts = NULL; /* Now rbdc->client is responsible for ceph_opts */
 762 
 763         ret = ceph_open_session(rbdc->client);
 764         if (ret < 0)
 765                 goto out_client;
 766 
 767         spin_lock(&rbd_client_list_lock);
 768         list_add_tail(&rbdc->node, &rbd_client_list);
 769         spin_unlock(&rbd_client_list_lock);
 770 
 771         dout("%s: rbdc %p\n", __func__, rbdc);
 772 
 773         return rbdc;
 774 out_client:
 775         ceph_destroy_client(rbdc->client);
 776 out_rbdc:
 777         kfree(rbdc);
 778 out_opt:
 779         if (ceph_opts)
 780                 ceph_destroy_options(ceph_opts);
 781         dout("%s: error %d\n", __func__, ret);
 782 
 783         return ERR_PTR(ret);
 784 }
 785 
 786 static struct rbd_client *__rbd_get_client(struct rbd_client *rbdc)
 787 {
 788         kref_get(&rbdc->kref);
 789 
 790         return rbdc;
 791 }
 792 
 793 /*
 794  * Find a ceph client with specific addr and configuration.  If
 795  * found, bump its reference count.
 796  */
 797 static struct rbd_client *rbd_client_find(struct ceph_options *ceph_opts)
 798 {
 799         struct rbd_client *client_node;
 800         bool found = false;
 801 
 802         if (ceph_opts->flags & CEPH_OPT_NOSHARE)
 803                 return NULL;
 804 
 805         spin_lock(&rbd_client_list_lock);
 806         list_for_each_entry(client_node, &rbd_client_list, node) {
 807                 if (!ceph_compare_options(ceph_opts, client_node->client)) {
 808                         __rbd_get_client(client_node);
 809 
 810                         found = true;
 811                         break;
 812                 }
 813         }
 814         spin_unlock(&rbd_client_list_lock);
 815 
 816         return found ? client_node : NULL;
 817 }
 818 
 819 /*
 820  * (Per device) rbd map options
 821  */
 822 enum {
 823         Opt_queue_depth,
 824         Opt_alloc_size,
 825         Opt_lock_timeout,
 826         Opt_last_int,
 827         /* int args above */
 828         Opt_pool_ns,
 829         Opt_last_string,
 830         /* string args above */
 831         Opt_read_only,
 832         Opt_read_write,
 833         Opt_lock_on_read,
 834         Opt_exclusive,
 835         Opt_notrim,
 836         Opt_err
 837 };
 838 
 839 static match_table_t rbd_opts_tokens = {
 840         {Opt_queue_depth, "queue_depth=%d"},
 841         {Opt_alloc_size, "alloc_size=%d"},
 842         {Opt_lock_timeout, "lock_timeout=%d"},
 843         /* int args above */
 844         {Opt_pool_ns, "_pool_ns=%s"},
 845         /* string args above */
 846         {Opt_read_only, "read_only"},
 847         {Opt_read_only, "ro"},          /* Alternate spelling */
 848         {Opt_read_write, "read_write"},
 849         {Opt_read_write, "rw"},         /* Alternate spelling */
 850         {Opt_lock_on_read, "lock_on_read"},
 851         {Opt_exclusive, "exclusive"},
 852         {Opt_notrim, "notrim"},
 853         {Opt_err, NULL}
 854 };
 855 
 856 struct rbd_options {
 857         int     queue_depth;
 858         int     alloc_size;
 859         unsigned long   lock_timeout;
 860         bool    read_only;
 861         bool    lock_on_read;
 862         bool    exclusive;
 863         bool    trim;
 864 };
 865 
 866 #define RBD_QUEUE_DEPTH_DEFAULT BLKDEV_MAX_RQ
 867 #define RBD_ALLOC_SIZE_DEFAULT  (64 * 1024)
 868 #define RBD_LOCK_TIMEOUT_DEFAULT 0  /* no timeout */
 869 #define RBD_READ_ONLY_DEFAULT   false
 870 #define RBD_LOCK_ON_READ_DEFAULT false
 871 #define RBD_EXCLUSIVE_DEFAULT   false
 872 #define RBD_TRIM_DEFAULT        true
 873 
 874 struct parse_rbd_opts_ctx {
 875         struct rbd_spec         *spec;
 876         struct rbd_options      *opts;
 877 };
 878 
 879 static int parse_rbd_opts_token(char *c, void *private)
 880 {
 881         struct parse_rbd_opts_ctx *pctx = private;
 882         substring_t argstr[MAX_OPT_ARGS];
 883         int token, intval, ret;
 884 
 885         token = match_token(c, rbd_opts_tokens, argstr);
 886         if (token < Opt_last_int) {
 887                 ret = match_int(&argstr[0], &intval);
 888                 if (ret < 0) {
 889                         pr_err("bad option arg (not int) at '%s'\n", c);
 890                         return ret;
 891                 }
 892                 dout("got int token %d val %d\n", token, intval);
 893         } else if (token > Opt_last_int && token < Opt_last_string) {
 894                 dout("got string token %d val %s\n", token, argstr[0].from);
 895         } else {
 896                 dout("got token %d\n", token);
 897         }
 898 
 899         switch (token) {
 900         case Opt_queue_depth:
 901                 if (intval < 1) {
 902                         pr_err("queue_depth out of range\n");
 903                         return -EINVAL;
 904                 }
 905                 pctx->opts->queue_depth = intval;
 906                 break;
 907         case Opt_alloc_size:
 908                 if (intval < SECTOR_SIZE) {
 909                         pr_err("alloc_size out of range\n");
 910                         return -EINVAL;
 911                 }
 912                 if (!is_power_of_2(intval)) {
 913                         pr_err("alloc_size must be a power of 2\n");
 914                         return -EINVAL;
 915                 }
 916                 pctx->opts->alloc_size = intval;
 917                 break;
 918         case Opt_lock_timeout:
 919                 /* 0 is "wait forever" (i.e. infinite timeout) */
 920                 if (intval < 0 || intval > INT_MAX / 1000) {
 921                         pr_err("lock_timeout out of range\n");
 922                         return -EINVAL;
 923                 }
 924                 pctx->opts->lock_timeout = msecs_to_jiffies(intval * 1000);
 925                 break;
 926         case Opt_pool_ns:
 927                 kfree(pctx->spec->pool_ns);
 928                 pctx->spec->pool_ns = match_strdup(argstr);
 929                 if (!pctx->spec->pool_ns)
 930                         return -ENOMEM;
 931                 break;
 932         case Opt_read_only:
 933                 pctx->opts->read_only = true;
 934                 break;
 935         case Opt_read_write:
 936                 pctx->opts->read_only = false;
 937                 break;
 938         case Opt_lock_on_read:
 939                 pctx->opts->lock_on_read = true;
 940                 break;
 941         case Opt_exclusive:
 942                 pctx->opts->exclusive = true;
 943                 break;
 944         case Opt_notrim:
 945                 pctx->opts->trim = false;
 946                 break;
 947         default:
 948                 /* libceph prints "bad option" msg */
 949                 return -EINVAL;
 950         }
 951 
 952         return 0;
 953 }
 954 
 955 static char* obj_op_name(enum obj_operation_type op_type)
 956 {
 957         switch (op_type) {
 958         case OBJ_OP_READ:
 959                 return "read";
 960         case OBJ_OP_WRITE:
 961                 return "write";
 962         case OBJ_OP_DISCARD:
 963                 return "discard";
 964         case OBJ_OP_ZEROOUT:
 965                 return "zeroout";
 966         default:
 967                 return "???";
 968         }
 969 }
 970 
 971 /*
 972  * Destroy ceph client
 973  *
 974  * Caller must hold rbd_client_list_lock.
 975  */
 976 static void rbd_client_release(struct kref *kref)
 977 {
 978         struct rbd_client *rbdc = container_of(kref, struct rbd_client, kref);
 979 
 980         dout("%s: rbdc %p\n", __func__, rbdc);
 981         spin_lock(&rbd_client_list_lock);
 982         list_del(&rbdc->node);
 983         spin_unlock(&rbd_client_list_lock);
 984 
 985         ceph_destroy_client(rbdc->client);
 986         kfree(rbdc);
 987 }
 988 
 989 /*
 990  * Drop reference to ceph client node. If it's not referenced anymore, release
 991  * it.
 992  */
 993 static void rbd_put_client(struct rbd_client *rbdc)
 994 {
 995         if (rbdc)
 996                 kref_put(&rbdc->kref, rbd_client_release);
 997 }
 998 
 999 /*
1000  * Get a ceph client with specific addr and configuration, if one does
1001  * not exist create it.  Either way, ceph_opts is consumed by this
1002  * function.
1003  */
1004 static struct rbd_client *rbd_get_client(struct ceph_options *ceph_opts)
1005 {
1006         struct rbd_client *rbdc;
1007         int ret;
1008 
1009         mutex_lock(&client_mutex);
1010         rbdc = rbd_client_find(ceph_opts);
1011         if (rbdc) {
1012                 ceph_destroy_options(ceph_opts);
1013 
1014                 /*
1015                  * Using an existing client.  Make sure ->pg_pools is up to
1016                  * date before we look up the pool id in do_rbd_add().
1017                  */
1018                 ret = ceph_wait_for_latest_osdmap(rbdc->client,
1019                                         rbdc->client->options->mount_timeout);
1020                 if (ret) {
1021                         rbd_warn(NULL, "failed to get latest osdmap: %d", ret);
1022                         rbd_put_client(rbdc);
1023                         rbdc = ERR_PTR(ret);
1024                 }
1025         } else {
1026                 rbdc = rbd_client_create(ceph_opts);
1027         }
1028         mutex_unlock(&client_mutex);
1029 
1030         return rbdc;
1031 }
1032 
1033 static bool rbd_image_format_valid(u32 image_format)
1034 {
1035         return image_format == 1 || image_format == 2;
1036 }
1037 
1038 static bool rbd_dev_ondisk_valid(struct rbd_image_header_ondisk *ondisk)
1039 {
1040         size_t size;
1041         u32 snap_count;
1042 
1043         /* The header has to start with the magic rbd header text */
1044         if (memcmp(&ondisk->text, RBD_HEADER_TEXT, sizeof (RBD_HEADER_TEXT)))
1045                 return false;
1046 
1047         /* The bio layer requires at least sector-sized I/O */
1048 
1049         if (ondisk->options.order < SECTOR_SHIFT)
1050                 return false;
1051 
1052         /* If we use u64 in a few spots we may be able to loosen this */
1053 
1054         if (ondisk->options.order > 8 * sizeof (int) - 1)
1055                 return false;
1056 
1057         /*
1058          * The size of a snapshot header has to fit in a size_t, and
1059          * that limits the number of snapshots.
1060          */
1061         snap_count = le32_to_cpu(ondisk->snap_count);
1062         size = SIZE_MAX - sizeof (struct ceph_snap_context);
1063         if (snap_count > size / sizeof (__le64))
1064                 return false;
1065 
1066         /*
1067          * Not only that, but the size of the entire the snapshot
1068          * header must also be representable in a size_t.
1069          */
1070         size -= snap_count * sizeof (__le64);
1071         if ((u64) size < le64_to_cpu(ondisk->snap_names_len))
1072                 return false;
1073 
1074         return true;
1075 }
1076 
1077 /*
1078  * returns the size of an object in the image
1079  */
1080 static u32 rbd_obj_bytes(struct rbd_image_header *header)
1081 {
1082         return 1U << header->obj_order;
1083 }
1084 
1085 static void rbd_init_layout(struct rbd_device *rbd_dev)
1086 {
1087         if (rbd_dev->header.stripe_unit == 0 ||
1088             rbd_dev->header.stripe_count == 0) {
1089                 rbd_dev->header.stripe_unit = rbd_obj_bytes(&rbd_dev->header);
1090                 rbd_dev->header.stripe_count = 1;
1091         }
1092 
1093         rbd_dev->layout.stripe_unit = rbd_dev->header.stripe_unit;
1094         rbd_dev->layout.stripe_count = rbd_dev->header.stripe_count;
1095         rbd_dev->layout.object_size = rbd_obj_bytes(&rbd_dev->header);
1096         rbd_dev->layout.pool_id = rbd_dev->header.data_pool_id == CEPH_NOPOOL ?
1097                           rbd_dev->spec->pool_id : rbd_dev->header.data_pool_id;
1098         RCU_INIT_POINTER(rbd_dev->layout.pool_ns, NULL);
1099 }
1100 
1101 /*
1102  * Fill an rbd image header with information from the given format 1
1103  * on-disk header.
1104  */
1105 static int rbd_header_from_disk(struct rbd_device *rbd_dev,
1106                                  struct rbd_image_header_ondisk *ondisk)
1107 {
1108         struct rbd_image_header *header = &rbd_dev->header;
1109         bool first_time = header->object_prefix == NULL;
1110         struct ceph_snap_context *snapc;
1111         char *object_prefix = NULL;
1112         char *snap_names = NULL;
1113         u64 *snap_sizes = NULL;
1114         u32 snap_count;
1115         int ret = -ENOMEM;
1116         u32 i;
1117 
1118         /* Allocate this now to avoid having to handle failure below */
1119 
1120         if (first_time) {
1121                 object_prefix = kstrndup(ondisk->object_prefix,
1122                                          sizeof(ondisk->object_prefix),
1123                                          GFP_KERNEL);
1124                 if (!object_prefix)
1125                         return -ENOMEM;
1126         }
1127 
1128         /* Allocate the snapshot context and fill it in */
1129 
1130         snap_count = le32_to_cpu(ondisk->snap_count);
1131         snapc = ceph_create_snap_context(snap_count, GFP_KERNEL);
1132         if (!snapc)
1133                 goto out_err;
1134         snapc->seq = le64_to_cpu(ondisk->snap_seq);
1135         if (snap_count) {
1136                 struct rbd_image_snap_ondisk *snaps;
1137                 u64 snap_names_len = le64_to_cpu(ondisk->snap_names_len);
1138 
1139                 /* We'll keep a copy of the snapshot names... */
1140 
1141                 if (snap_names_len > (u64)SIZE_MAX)
1142                         goto out_2big;
1143                 snap_names = kmalloc(snap_names_len, GFP_KERNEL);
1144                 if (!snap_names)
1145                         goto out_err;
1146 
1147                 /* ...as well as the array of their sizes. */
1148                 snap_sizes = kmalloc_array(snap_count,
1149                                            sizeof(*header->snap_sizes),
1150                                            GFP_KERNEL);
1151                 if (!snap_sizes)
1152                         goto out_err;
1153 
1154                 /*
1155                  * Copy the names, and fill in each snapshot's id
1156                  * and size.
1157                  *
1158                  * Note that rbd_dev_v1_header_info() guarantees the
1159                  * ondisk buffer we're working with has
1160                  * snap_names_len bytes beyond the end of the
1161                  * snapshot id array, this memcpy() is safe.
1162                  */
1163                 memcpy(snap_names, &ondisk->snaps[snap_count], snap_names_len);
1164                 snaps = ondisk->snaps;
1165                 for (i = 0; i < snap_count; i++) {
1166                         snapc->snaps[i] = le64_to_cpu(snaps[i].id);
1167                         snap_sizes[i] = le64_to_cpu(snaps[i].image_size);
1168                 }
1169         }
1170 
1171         /* We won't fail any more, fill in the header */
1172 
1173         if (first_time) {
1174                 header->object_prefix = object_prefix;
1175                 header->obj_order = ondisk->options.order;
1176                 rbd_init_layout(rbd_dev);
1177         } else {
1178                 ceph_put_snap_context(header->snapc);
1179                 kfree(header->snap_names);
1180                 kfree(header->snap_sizes);
1181         }
1182 
1183         /* The remaining fields always get updated (when we refresh) */
1184 
1185         header->image_size = le64_to_cpu(ondisk->image_size);
1186         header->snapc = snapc;
1187         header->snap_names = snap_names;
1188         header->snap_sizes = snap_sizes;
1189 
1190         return 0;
1191 out_2big:
1192         ret = -EIO;
1193 out_err:
1194         kfree(snap_sizes);
1195         kfree(snap_names);
1196         ceph_put_snap_context(snapc);
1197         kfree(object_prefix);
1198 
1199         return ret;
1200 }
1201 
1202 static const char *_rbd_dev_v1_snap_name(struct rbd_device *rbd_dev, u32 which)
1203 {
1204         const char *snap_name;
1205 
1206         rbd_assert(which < rbd_dev->header.snapc->num_snaps);
1207 
1208         /* Skip over names until we find the one we are looking for */
1209 
1210         snap_name = rbd_dev->header.snap_names;
1211         while (which--)
1212                 snap_name += strlen(snap_name) + 1;
1213 
1214         return kstrdup(snap_name, GFP_KERNEL);
1215 }
1216 
1217 /*
1218  * Snapshot id comparison function for use with qsort()/bsearch().
1219  * Note that result is for snapshots in *descending* order.
1220  */
1221 static int snapid_compare_reverse(const void *s1, const void *s2)
1222 {
1223         u64 snap_id1 = *(u64 *)s1;
1224         u64 snap_id2 = *(u64 *)s2;
1225 
1226         if (snap_id1 < snap_id2)
1227                 return 1;
1228         return snap_id1 == snap_id2 ? 0 : -1;
1229 }
1230 
1231 /*
1232  * Search a snapshot context to see if the given snapshot id is
1233  * present.
1234  *
1235  * Returns the position of the snapshot id in the array if it's found,
1236  * or BAD_SNAP_INDEX otherwise.
1237  *
1238  * Note: The snapshot array is in kept sorted (by the osd) in
1239  * reverse order, highest snapshot id first.
1240  */
1241 static u32 rbd_dev_snap_index(struct rbd_device *rbd_dev, u64 snap_id)
1242 {
1243         struct ceph_snap_context *snapc = rbd_dev->header.snapc;
1244         u64 *found;
1245 
1246         found = bsearch(&snap_id, &snapc->snaps, snapc->num_snaps,
1247                                 sizeof (snap_id), snapid_compare_reverse);
1248 
1249         return found ? (u32)(found - &snapc->snaps[0]) : BAD_SNAP_INDEX;
1250 }
1251 
1252 static const char *rbd_dev_v1_snap_name(struct rbd_device *rbd_dev,
1253                                         u64 snap_id)
1254 {
1255         u32 which;
1256         const char *snap_name;
1257 
1258         which = rbd_dev_snap_index(rbd_dev, snap_id);
1259         if (which == BAD_SNAP_INDEX)
1260                 return ERR_PTR(-ENOENT);
1261 
1262         snap_name = _rbd_dev_v1_snap_name(rbd_dev, which);
1263         return snap_name ? snap_name : ERR_PTR(-ENOMEM);
1264 }
1265 
1266 static const char *rbd_snap_name(struct rbd_device *rbd_dev, u64 snap_id)
1267 {
1268         if (snap_id == CEPH_NOSNAP)
1269                 return RBD_SNAP_HEAD_NAME;
1270 
1271         rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
1272         if (rbd_dev->image_format == 1)
1273                 return rbd_dev_v1_snap_name(rbd_dev, snap_id);
1274 
1275         return rbd_dev_v2_snap_name(rbd_dev, snap_id);
1276 }
1277 
1278 static int rbd_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
1279                                 u64 *snap_size)
1280 {
1281         rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
1282         if (snap_id == CEPH_NOSNAP) {
1283                 *snap_size = rbd_dev->header.image_size;
1284         } else if (rbd_dev->image_format == 1) {
1285                 u32 which;
1286 
1287                 which = rbd_dev_snap_index(rbd_dev, snap_id);
1288                 if (which == BAD_SNAP_INDEX)
1289                         return -ENOENT;
1290 
1291                 *snap_size = rbd_dev->header.snap_sizes[which];
1292         } else {
1293                 u64 size = 0;
1294                 int ret;
1295 
1296                 ret = _rbd_dev_v2_snap_size(rbd_dev, snap_id, NULL, &size);
1297                 if (ret)
1298                         return ret;
1299 
1300                 *snap_size = size;
1301         }
1302         return 0;
1303 }
1304 
1305 static int rbd_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
1306                         u64 *snap_features)
1307 {
1308         rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
1309         if (snap_id == CEPH_NOSNAP) {
1310                 *snap_features = rbd_dev->header.features;
1311         } else if (rbd_dev->image_format == 1) {
1312                 *snap_features = 0;     /* No features for format 1 */
1313         } else {
1314                 u64 features = 0;
1315                 int ret;
1316 
1317                 ret = _rbd_dev_v2_snap_features(rbd_dev, snap_id, &features);
1318                 if (ret)
1319                         return ret;
1320 
1321                 *snap_features = features;
1322         }
1323         return 0;
1324 }
1325 
1326 static int rbd_dev_mapping_set(struct rbd_device *rbd_dev)
1327 {
1328         u64 snap_id = rbd_dev->spec->snap_id;
1329         u64 size = 0;
1330         u64 features = 0;
1331         int ret;
1332 
1333         ret = rbd_snap_size(rbd_dev, snap_id, &size);
1334         if (ret)
1335                 return ret;
1336         ret = rbd_snap_features(rbd_dev, snap_id, &features);
1337         if (ret)
1338                 return ret;
1339 
1340         rbd_dev->mapping.size = size;
1341         rbd_dev->mapping.features = features;
1342 
1343         return 0;
1344 }
1345 
1346 static void rbd_dev_mapping_clear(struct rbd_device *rbd_dev)
1347 {
1348         rbd_dev->mapping.size = 0;
1349         rbd_dev->mapping.features = 0;
1350 }
1351 
1352 static void zero_bvec(struct bio_vec *bv)
1353 {
1354         void *buf;
1355         unsigned long flags;
1356 
1357         buf = bvec_kmap_irq(bv, &flags);
1358         memset(buf, 0, bv->bv_len);
1359         flush_dcache_page(bv->bv_page);
1360         bvec_kunmap_irq(buf, &flags);
1361 }
1362 
1363 static void zero_bios(struct ceph_bio_iter *bio_pos, u32 off, u32 bytes)
1364 {
1365         struct ceph_bio_iter it = *bio_pos;
1366 
1367         ceph_bio_iter_advance(&it, off);
1368         ceph_bio_iter_advance_step(&it, bytes, ({
1369                 zero_bvec(&bv);
1370         }));
1371 }
1372 
1373 static void zero_bvecs(struct ceph_bvec_iter *bvec_pos, u32 off, u32 bytes)
1374 {
1375         struct ceph_bvec_iter it = *bvec_pos;
1376 
1377         ceph_bvec_iter_advance(&it, off);
1378         ceph_bvec_iter_advance_step(&it, bytes, ({
1379                 zero_bvec(&bv);
1380         }));
1381 }
1382 
1383 /*
1384  * Zero a range in @obj_req data buffer defined by a bio (list) or
1385  * (private) bio_vec array.
1386  *
1387  * @off is relative to the start of the data buffer.
1388  */
1389 static void rbd_obj_zero_range(struct rbd_obj_request *obj_req, u32 off,
1390                                u32 bytes)
1391 {
1392         dout("%s %p data buf %u~%u\n", __func__, obj_req, off, bytes);
1393 
1394         switch (obj_req->img_request->data_type) {
1395         case OBJ_REQUEST_BIO:
1396                 zero_bios(&obj_req->bio_pos, off, bytes);
1397                 break;
1398         case OBJ_REQUEST_BVECS:
1399         case OBJ_REQUEST_OWN_BVECS:
1400                 zero_bvecs(&obj_req->bvec_pos, off, bytes);
1401                 break;
1402         default:
1403                 BUG();
1404         }
1405 }
1406 
1407 static void rbd_obj_request_destroy(struct kref *kref);
1408 static void rbd_obj_request_put(struct rbd_obj_request *obj_request)
1409 {
1410         rbd_assert(obj_request != NULL);
1411         dout("%s: obj %p (was %d)\n", __func__, obj_request,
1412                 kref_read(&obj_request->kref));
1413         kref_put(&obj_request->kref, rbd_obj_request_destroy);
1414 }
1415 
1416 static void rbd_img_request_destroy(struct kref *kref);
1417 static void rbd_img_request_put(struct rbd_img_request *img_request)
1418 {
1419         rbd_assert(img_request != NULL);
1420         dout("%s: img %p (was %d)\n", __func__, img_request,
1421                 kref_read(&img_request->kref));
1422         kref_put(&img_request->kref, rbd_img_request_destroy);
1423 }
1424 
1425 static inline void rbd_img_obj_request_add(struct rbd_img_request *img_request,
1426                                         struct rbd_obj_request *obj_request)
1427 {
1428         rbd_assert(obj_request->img_request == NULL);
1429 
1430         /* Image request now owns object's original reference */
1431         obj_request->img_request = img_request;
1432         dout("%s: img %p obj %p\n", __func__, img_request, obj_request);
1433 }
1434 
1435 static inline void rbd_img_obj_request_del(struct rbd_img_request *img_request,
1436                                         struct rbd_obj_request *obj_request)
1437 {
1438         dout("%s: img %p obj %p\n", __func__, img_request, obj_request);
1439         list_del(&obj_request->ex.oe_item);
1440         rbd_assert(obj_request->img_request == img_request);
1441         rbd_obj_request_put(obj_request);
1442 }
1443 
1444 static void rbd_osd_submit(struct ceph_osd_request *osd_req)
1445 {
1446         struct rbd_obj_request *obj_req = osd_req->r_priv;
1447 
1448         dout("%s osd_req %p for obj_req %p objno %llu %llu~%llu\n",
1449              __func__, osd_req, obj_req, obj_req->ex.oe_objno,
1450              obj_req->ex.oe_off, obj_req->ex.oe_len);
1451         ceph_osdc_start_request(osd_req->r_osdc, osd_req, false);
1452 }
1453 
1454 /*
1455  * The default/initial value for all image request flags is 0.  Each
1456  * is conditionally set to 1 at image request initialization time
1457  * and currently never change thereafter.
1458  */
1459 static void img_request_layered_set(struct rbd_img_request *img_request)
1460 {
1461         set_bit(IMG_REQ_LAYERED, &img_request->flags);
1462         smp_mb();
1463 }
1464 
1465 static void img_request_layered_clear(struct rbd_img_request *img_request)
1466 {
1467         clear_bit(IMG_REQ_LAYERED, &img_request->flags);
1468         smp_mb();
1469 }
1470 
1471 static bool img_request_layered_test(struct rbd_img_request *img_request)
1472 {
1473         smp_mb();
1474         return test_bit(IMG_REQ_LAYERED, &img_request->flags) != 0;
1475 }
1476 
1477 static bool rbd_obj_is_entire(struct rbd_obj_request *obj_req)
1478 {
1479         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
1480 
1481         return !obj_req->ex.oe_off &&
1482                obj_req->ex.oe_len == rbd_dev->layout.object_size;
1483 }
1484 
1485 static bool rbd_obj_is_tail(struct rbd_obj_request *obj_req)
1486 {
1487         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
1488 
1489         return obj_req->ex.oe_off + obj_req->ex.oe_len ==
1490                                         rbd_dev->layout.object_size;
1491 }
1492 
1493 /*
1494  * Must be called after rbd_obj_calc_img_extents().
1495  */
1496 static bool rbd_obj_copyup_enabled(struct rbd_obj_request *obj_req)
1497 {
1498         if (!obj_req->num_img_extents ||
1499             (rbd_obj_is_entire(obj_req) &&
1500              !obj_req->img_request->snapc->num_snaps))
1501                 return false;
1502 
1503         return true;
1504 }
1505 
1506 static u64 rbd_obj_img_extents_bytes(struct rbd_obj_request *obj_req)
1507 {
1508         return ceph_file_extents_bytes(obj_req->img_extents,
1509                                        obj_req->num_img_extents);
1510 }
1511 
1512 static bool rbd_img_is_write(struct rbd_img_request *img_req)
1513 {
1514         switch (img_req->op_type) {
1515         case OBJ_OP_READ:
1516                 return false;
1517         case OBJ_OP_WRITE:
1518         case OBJ_OP_DISCARD:
1519         case OBJ_OP_ZEROOUT:
1520                 return true;
1521         default:
1522                 BUG();
1523         }
1524 }
1525 
1526 static void rbd_osd_req_callback(struct ceph_osd_request *osd_req)
1527 {
1528         struct rbd_obj_request *obj_req = osd_req->r_priv;
1529         int result;
1530 
1531         dout("%s osd_req %p result %d for obj_req %p\n", __func__, osd_req,
1532              osd_req->r_result, obj_req);
1533 
1534         /*
1535          * Writes aren't allowed to return a data payload.  In some
1536          * guarded write cases (e.g. stat + zero on an empty object)
1537          * a stat response makes it through, but we don't care.
1538          */
1539         if (osd_req->r_result > 0 && rbd_img_is_write(obj_req->img_request))
1540                 result = 0;
1541         else
1542                 result = osd_req->r_result;
1543 
1544         rbd_obj_handle_request(obj_req, result);
1545 }
1546 
1547 static void rbd_osd_format_read(struct ceph_osd_request *osd_req)
1548 {
1549         struct rbd_obj_request *obj_request = osd_req->r_priv;
1550 
1551         osd_req->r_flags = CEPH_OSD_FLAG_READ;
1552         osd_req->r_snapid = obj_request->img_request->snap_id;
1553 }
1554 
1555 static void rbd_osd_format_write(struct ceph_osd_request *osd_req)
1556 {
1557         struct rbd_obj_request *obj_request = osd_req->r_priv;
1558 
1559         osd_req->r_flags = CEPH_OSD_FLAG_WRITE;
1560         ktime_get_real_ts64(&osd_req->r_mtime);
1561         osd_req->r_data_offset = obj_request->ex.oe_off;
1562 }
1563 
1564 static struct ceph_osd_request *
1565 __rbd_obj_add_osd_request(struct rbd_obj_request *obj_req,
1566                           struct ceph_snap_context *snapc, int num_ops)
1567 {
1568         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
1569         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
1570         struct ceph_osd_request *req;
1571         const char *name_format = rbd_dev->image_format == 1 ?
1572                                       RBD_V1_DATA_FORMAT : RBD_V2_DATA_FORMAT;
1573         int ret;
1574 
1575         req = ceph_osdc_alloc_request(osdc, snapc, num_ops, false, GFP_NOIO);
1576         if (!req)
1577                 return ERR_PTR(-ENOMEM);
1578 
1579         list_add_tail(&req->r_private_item, &obj_req->osd_reqs);
1580         req->r_callback = rbd_osd_req_callback;
1581         req->r_priv = obj_req;
1582 
1583         /*
1584          * Data objects may be stored in a separate pool, but always in
1585          * the same namespace in that pool as the header in its pool.
1586          */
1587         ceph_oloc_copy(&req->r_base_oloc, &rbd_dev->header_oloc);
1588         req->r_base_oloc.pool = rbd_dev->layout.pool_id;
1589 
1590         ret = ceph_oid_aprintf(&req->r_base_oid, GFP_NOIO, name_format,
1591                                rbd_dev->header.object_prefix,
1592                                obj_req->ex.oe_objno);
1593         if (ret)
1594                 return ERR_PTR(ret);
1595 
1596         return req;
1597 }
1598 
1599 static struct ceph_osd_request *
1600 rbd_obj_add_osd_request(struct rbd_obj_request *obj_req, int num_ops)
1601 {
1602         return __rbd_obj_add_osd_request(obj_req, obj_req->img_request->snapc,
1603                                          num_ops);
1604 }
1605 
1606 static struct rbd_obj_request *rbd_obj_request_create(void)
1607 {
1608         struct rbd_obj_request *obj_request;
1609 
1610         obj_request = kmem_cache_zalloc(rbd_obj_request_cache, GFP_NOIO);
1611         if (!obj_request)
1612                 return NULL;
1613 
1614         ceph_object_extent_init(&obj_request->ex);
1615         INIT_LIST_HEAD(&obj_request->osd_reqs);
1616         mutex_init(&obj_request->state_mutex);
1617         kref_init(&obj_request->kref);
1618 
1619         dout("%s %p\n", __func__, obj_request);
1620         return obj_request;
1621 }
1622 
1623 static void rbd_obj_request_destroy(struct kref *kref)
1624 {
1625         struct rbd_obj_request *obj_request;
1626         struct ceph_osd_request *osd_req;
1627         u32 i;
1628 
1629         obj_request = container_of(kref, struct rbd_obj_request, kref);
1630 
1631         dout("%s: obj %p\n", __func__, obj_request);
1632 
1633         while (!list_empty(&obj_request->osd_reqs)) {
1634                 osd_req = list_first_entry(&obj_request->osd_reqs,
1635                                     struct ceph_osd_request, r_private_item);
1636                 list_del_init(&osd_req->r_private_item);
1637                 ceph_osdc_put_request(osd_req);
1638         }
1639 
1640         switch (obj_request->img_request->data_type) {
1641         case OBJ_REQUEST_NODATA:
1642         case OBJ_REQUEST_BIO:
1643         case OBJ_REQUEST_BVECS:
1644                 break;          /* Nothing to do */
1645         case OBJ_REQUEST_OWN_BVECS:
1646                 kfree(obj_request->bvec_pos.bvecs);
1647                 break;
1648         default:
1649                 BUG();
1650         }
1651 
1652         kfree(obj_request->img_extents);
1653         if (obj_request->copyup_bvecs) {
1654                 for (i = 0; i < obj_request->copyup_bvec_count; i++) {
1655                         if (obj_request->copyup_bvecs[i].bv_page)
1656                                 __free_page(obj_request->copyup_bvecs[i].bv_page);
1657                 }
1658                 kfree(obj_request->copyup_bvecs);
1659         }
1660 
1661         kmem_cache_free(rbd_obj_request_cache, obj_request);
1662 }
1663 
1664 /* It's OK to call this for a device with no parent */
1665 
1666 static void rbd_spec_put(struct rbd_spec *spec);
1667 static void rbd_dev_unparent(struct rbd_device *rbd_dev)
1668 {
1669         rbd_dev_remove_parent(rbd_dev);
1670         rbd_spec_put(rbd_dev->parent_spec);
1671         rbd_dev->parent_spec = NULL;
1672         rbd_dev->parent_overlap = 0;
1673 }
1674 
1675 /*
1676  * Parent image reference counting is used to determine when an
1677  * image's parent fields can be safely torn down--after there are no
1678  * more in-flight requests to the parent image.  When the last
1679  * reference is dropped, cleaning them up is safe.
1680  */
1681 static void rbd_dev_parent_put(struct rbd_device *rbd_dev)
1682 {
1683         int counter;
1684 
1685         if (!rbd_dev->parent_spec)
1686                 return;
1687 
1688         counter = atomic_dec_return_safe(&rbd_dev->parent_ref);
1689         if (counter > 0)
1690                 return;
1691 
1692         /* Last reference; clean up parent data structures */
1693 
1694         if (!counter)
1695                 rbd_dev_unparent(rbd_dev);
1696         else
1697                 rbd_warn(rbd_dev, "parent reference underflow");
1698 }
1699 
1700 /*
1701  * If an image has a non-zero parent overlap, get a reference to its
1702  * parent.
1703  *
1704  * Returns true if the rbd device has a parent with a non-zero
1705  * overlap and a reference for it was successfully taken, or
1706  * false otherwise.
1707  */
1708 static bool rbd_dev_parent_get(struct rbd_device *rbd_dev)
1709 {
1710         int counter = 0;
1711 
1712         if (!rbd_dev->parent_spec)
1713                 return false;
1714 
1715         down_read(&rbd_dev->header_rwsem);
1716         if (rbd_dev->parent_overlap)
1717                 counter = atomic_inc_return_safe(&rbd_dev->parent_ref);
1718         up_read(&rbd_dev->header_rwsem);
1719 
1720         if (counter < 0)
1721                 rbd_warn(rbd_dev, "parent reference overflow");
1722 
1723         return counter > 0;
1724 }
1725 
1726 /*
1727  * Caller is responsible for filling in the list of object requests
1728  * that comprises the image request, and the Linux request pointer
1729  * (if there is one).
1730  */
1731 static struct rbd_img_request *rbd_img_request_create(
1732                                         struct rbd_device *rbd_dev,
1733                                         enum obj_operation_type op_type,
1734                                         struct ceph_snap_context *snapc)
1735 {
1736         struct rbd_img_request *img_request;
1737 
1738         img_request = kmem_cache_zalloc(rbd_img_request_cache, GFP_NOIO);
1739         if (!img_request)
1740                 return NULL;
1741 
1742         img_request->rbd_dev = rbd_dev;
1743         img_request->op_type = op_type;
1744         if (!rbd_img_is_write(img_request))
1745                 img_request->snap_id = rbd_dev->spec->snap_id;
1746         else
1747                 img_request->snapc = snapc;
1748 
1749         if (rbd_dev_parent_get(rbd_dev))
1750                 img_request_layered_set(img_request);
1751 
1752         INIT_LIST_HEAD(&img_request->lock_item);
1753         INIT_LIST_HEAD(&img_request->object_extents);
1754         mutex_init(&img_request->state_mutex);
1755         kref_init(&img_request->kref);
1756 
1757         return img_request;
1758 }
1759 
1760 static void rbd_img_request_destroy(struct kref *kref)
1761 {
1762         struct rbd_img_request *img_request;
1763         struct rbd_obj_request *obj_request;
1764         struct rbd_obj_request *next_obj_request;
1765 
1766         img_request = container_of(kref, struct rbd_img_request, kref);
1767 
1768         dout("%s: img %p\n", __func__, img_request);
1769 
1770         WARN_ON(!list_empty(&img_request->lock_item));
1771         for_each_obj_request_safe(img_request, obj_request, next_obj_request)
1772                 rbd_img_obj_request_del(img_request, obj_request);
1773 
1774         if (img_request_layered_test(img_request)) {
1775                 img_request_layered_clear(img_request);
1776                 rbd_dev_parent_put(img_request->rbd_dev);
1777         }
1778 
1779         if (rbd_img_is_write(img_request))
1780                 ceph_put_snap_context(img_request->snapc);
1781 
1782         kmem_cache_free(rbd_img_request_cache, img_request);
1783 }
1784 
1785 #define BITS_PER_OBJ    2
1786 #define OBJS_PER_BYTE   (BITS_PER_BYTE / BITS_PER_OBJ)
1787 #define OBJ_MASK        ((1 << BITS_PER_OBJ) - 1)
1788 
1789 static void __rbd_object_map_index(struct rbd_device *rbd_dev, u64 objno,
1790                                    u64 *index, u8 *shift)
1791 {
1792         u32 off;
1793 
1794         rbd_assert(objno < rbd_dev->object_map_size);
1795         *index = div_u64_rem(objno, OBJS_PER_BYTE, &off);
1796         *shift = (OBJS_PER_BYTE - off - 1) * BITS_PER_OBJ;
1797 }
1798 
1799 static u8 __rbd_object_map_get(struct rbd_device *rbd_dev, u64 objno)
1800 {
1801         u64 index;
1802         u8 shift;
1803 
1804         lockdep_assert_held(&rbd_dev->object_map_lock);
1805         __rbd_object_map_index(rbd_dev, objno, &index, &shift);
1806         return (rbd_dev->object_map[index] >> shift) & OBJ_MASK;
1807 }
1808 
1809 static void __rbd_object_map_set(struct rbd_device *rbd_dev, u64 objno, u8 val)
1810 {
1811         u64 index;
1812         u8 shift;
1813         u8 *p;
1814 
1815         lockdep_assert_held(&rbd_dev->object_map_lock);
1816         rbd_assert(!(val & ~OBJ_MASK));
1817 
1818         __rbd_object_map_index(rbd_dev, objno, &index, &shift);
1819         p = &rbd_dev->object_map[index];
1820         *p = (*p & ~(OBJ_MASK << shift)) | (val << shift);
1821 }
1822 
1823 static u8 rbd_object_map_get(struct rbd_device *rbd_dev, u64 objno)
1824 {
1825         u8 state;
1826 
1827         spin_lock(&rbd_dev->object_map_lock);
1828         state = __rbd_object_map_get(rbd_dev, objno);
1829         spin_unlock(&rbd_dev->object_map_lock);
1830         return state;
1831 }
1832 
1833 static bool use_object_map(struct rbd_device *rbd_dev)
1834 {
1835         return ((rbd_dev->header.features & RBD_FEATURE_OBJECT_MAP) &&
1836                 !(rbd_dev->object_map_flags & RBD_FLAG_OBJECT_MAP_INVALID));
1837 }
1838 
1839 static bool rbd_object_map_may_exist(struct rbd_device *rbd_dev, u64 objno)
1840 {
1841         u8 state;
1842 
1843         /* fall back to default logic if object map is disabled or invalid */
1844         if (!use_object_map(rbd_dev))
1845                 return true;
1846 
1847         state = rbd_object_map_get(rbd_dev, objno);
1848         return state != OBJECT_NONEXISTENT;
1849 }
1850 
1851 static void rbd_object_map_name(struct rbd_device *rbd_dev, u64 snap_id,
1852                                 struct ceph_object_id *oid)
1853 {
1854         if (snap_id == CEPH_NOSNAP)
1855                 ceph_oid_printf(oid, "%s%s", RBD_OBJECT_MAP_PREFIX,
1856                                 rbd_dev->spec->image_id);
1857         else
1858                 ceph_oid_printf(oid, "%s%s.%016llx", RBD_OBJECT_MAP_PREFIX,
1859                                 rbd_dev->spec->image_id, snap_id);
1860 }
1861 
1862 static int rbd_object_map_lock(struct rbd_device *rbd_dev)
1863 {
1864         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
1865         CEPH_DEFINE_OID_ONSTACK(oid);
1866         u8 lock_type;
1867         char *lock_tag;
1868         struct ceph_locker *lockers;
1869         u32 num_lockers;
1870         bool broke_lock = false;
1871         int ret;
1872 
1873         rbd_object_map_name(rbd_dev, CEPH_NOSNAP, &oid);
1874 
1875 again:
1876         ret = ceph_cls_lock(osdc, &oid, &rbd_dev->header_oloc, RBD_LOCK_NAME,
1877                             CEPH_CLS_LOCK_EXCLUSIVE, "", "", "", 0);
1878         if (ret != -EBUSY || broke_lock) {
1879                 if (ret == -EEXIST)
1880                         ret = 0; /* already locked by myself */
1881                 if (ret)
1882                         rbd_warn(rbd_dev, "failed to lock object map: %d", ret);
1883                 return ret;
1884         }
1885 
1886         ret = ceph_cls_lock_info(osdc, &oid, &rbd_dev->header_oloc,
1887                                  RBD_LOCK_NAME, &lock_type, &lock_tag,
1888                                  &lockers, &num_lockers);
1889         if (ret) {
1890                 if (ret == -ENOENT)
1891                         goto again;
1892 
1893                 rbd_warn(rbd_dev, "failed to get object map lockers: %d", ret);
1894                 return ret;
1895         }
1896 
1897         kfree(lock_tag);
1898         if (num_lockers == 0)
1899                 goto again;
1900 
1901         rbd_warn(rbd_dev, "breaking object map lock owned by %s%llu",
1902                  ENTITY_NAME(lockers[0].id.name));
1903 
1904         ret = ceph_cls_break_lock(osdc, &oid, &rbd_dev->header_oloc,
1905                                   RBD_LOCK_NAME, lockers[0].id.cookie,
1906                                   &lockers[0].id.name);
1907         ceph_free_lockers(lockers, num_lockers);
1908         if (ret) {
1909                 if (ret == -ENOENT)
1910                         goto again;
1911 
1912                 rbd_warn(rbd_dev, "failed to break object map lock: %d", ret);
1913                 return ret;
1914         }
1915 
1916         broke_lock = true;
1917         goto again;
1918 }
1919 
1920 static void rbd_object_map_unlock(struct rbd_device *rbd_dev)
1921 {
1922         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
1923         CEPH_DEFINE_OID_ONSTACK(oid);
1924         int ret;
1925 
1926         rbd_object_map_name(rbd_dev, CEPH_NOSNAP, &oid);
1927 
1928         ret = ceph_cls_unlock(osdc, &oid, &rbd_dev->header_oloc, RBD_LOCK_NAME,
1929                               "");
1930         if (ret && ret != -ENOENT)
1931                 rbd_warn(rbd_dev, "failed to unlock object map: %d", ret);
1932 }
1933 
1934 static int decode_object_map_header(void **p, void *end, u64 *object_map_size)
1935 {
1936         u8 struct_v;
1937         u32 struct_len;
1938         u32 header_len;
1939         void *header_end;
1940         int ret;
1941 
1942         ceph_decode_32_safe(p, end, header_len, e_inval);
1943         header_end = *p + header_len;
1944 
1945         ret = ceph_start_decoding(p, end, 1, "BitVector header", &struct_v,
1946                                   &struct_len);
1947         if (ret)
1948                 return ret;
1949 
1950         ceph_decode_64_safe(p, end, *object_map_size, e_inval);
1951 
1952         *p = header_end;
1953         return 0;
1954 
1955 e_inval:
1956         return -EINVAL;
1957 }
1958 
1959 static int __rbd_object_map_load(struct rbd_device *rbd_dev)
1960 {
1961         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
1962         CEPH_DEFINE_OID_ONSTACK(oid);
1963         struct page **pages;
1964         void *p, *end;
1965         size_t reply_len;
1966         u64 num_objects;
1967         u64 object_map_bytes;
1968         u64 object_map_size;
1969         int num_pages;
1970         int ret;
1971 
1972         rbd_assert(!rbd_dev->object_map && !rbd_dev->object_map_size);
1973 
1974         num_objects = ceph_get_num_objects(&rbd_dev->layout,
1975                                            rbd_dev->mapping.size);
1976         object_map_bytes = DIV_ROUND_UP_ULL(num_objects * BITS_PER_OBJ,
1977                                             BITS_PER_BYTE);
1978         num_pages = calc_pages_for(0, object_map_bytes) + 1;
1979         pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
1980         if (IS_ERR(pages))
1981                 return PTR_ERR(pages);
1982 
1983         reply_len = num_pages * PAGE_SIZE;
1984         rbd_object_map_name(rbd_dev, rbd_dev->spec->snap_id, &oid);
1985         ret = ceph_osdc_call(osdc, &oid, &rbd_dev->header_oloc,
1986                              "rbd", "object_map_load", CEPH_OSD_FLAG_READ,
1987                              NULL, 0, pages, &reply_len);
1988         if (ret)
1989                 goto out;
1990 
1991         p = page_address(pages[0]);
1992         end = p + min(reply_len, (size_t)PAGE_SIZE);
1993         ret = decode_object_map_header(&p, end, &object_map_size);
1994         if (ret)
1995                 goto out;
1996 
1997         if (object_map_size != num_objects) {
1998                 rbd_warn(rbd_dev, "object map size mismatch: %llu vs %llu",
1999                          object_map_size, num_objects);
2000                 ret = -EINVAL;
2001                 goto out;
2002         }
2003 
2004         if (offset_in_page(p) + object_map_bytes > reply_len) {
2005                 ret = -EINVAL;
2006                 goto out;
2007         }
2008 
2009         rbd_dev->object_map = kvmalloc(object_map_bytes, GFP_KERNEL);
2010         if (!rbd_dev->object_map) {
2011                 ret = -ENOMEM;
2012                 goto out;
2013         }
2014 
2015         rbd_dev->object_map_size = object_map_size;
2016         ceph_copy_from_page_vector(pages, rbd_dev->object_map,
2017                                    offset_in_page(p), object_map_bytes);
2018 
2019 out:
2020         ceph_release_page_vector(pages, num_pages);
2021         return ret;
2022 }
2023 
2024 static void rbd_object_map_free(struct rbd_device *rbd_dev)
2025 {
2026         kvfree(rbd_dev->object_map);
2027         rbd_dev->object_map = NULL;
2028         rbd_dev->object_map_size = 0;
2029 }
2030 
2031 static int rbd_object_map_load(struct rbd_device *rbd_dev)
2032 {
2033         int ret;
2034 
2035         ret = __rbd_object_map_load(rbd_dev);
2036         if (ret)
2037                 return ret;
2038 
2039         ret = rbd_dev_v2_get_flags(rbd_dev);
2040         if (ret) {
2041                 rbd_object_map_free(rbd_dev);
2042                 return ret;
2043         }
2044 
2045         if (rbd_dev->object_map_flags & RBD_FLAG_OBJECT_MAP_INVALID)
2046                 rbd_warn(rbd_dev, "object map is invalid");
2047 
2048         return 0;
2049 }
2050 
2051 static int rbd_object_map_open(struct rbd_device *rbd_dev)
2052 {
2053         int ret;
2054 
2055         ret = rbd_object_map_lock(rbd_dev);
2056         if (ret)
2057                 return ret;
2058 
2059         ret = rbd_object_map_load(rbd_dev);
2060         if (ret) {
2061                 rbd_object_map_unlock(rbd_dev);
2062                 return ret;
2063         }
2064 
2065         return 0;
2066 }
2067 
2068 static void rbd_object_map_close(struct rbd_device *rbd_dev)
2069 {
2070         rbd_object_map_free(rbd_dev);
2071         rbd_object_map_unlock(rbd_dev);
2072 }
2073 
2074 /*
2075  * This function needs snap_id (or more precisely just something to
2076  * distinguish between HEAD and snapshot object maps), new_state and
2077  * current_state that were passed to rbd_object_map_update().
2078  *
2079  * To avoid allocating and stashing a context we piggyback on the OSD
2080  * request.  A HEAD update has two ops (assert_locked).  For new_state
2081  * and current_state we decode our own object_map_update op, encoded in
2082  * rbd_cls_object_map_update().
2083  */
2084 static int rbd_object_map_update_finish(struct rbd_obj_request *obj_req,
2085                                         struct ceph_osd_request *osd_req)
2086 {
2087         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
2088         struct ceph_osd_data *osd_data;
2089         u64 objno;
2090         u8 state, new_state, uninitialized_var(current_state);
2091         bool has_current_state;
2092         void *p;
2093 
2094         if (osd_req->r_result)
2095                 return osd_req->r_result;
2096 
2097         /*
2098          * Nothing to do for a snapshot object map.
2099          */
2100         if (osd_req->r_num_ops == 1)
2101                 return 0;
2102 
2103         /*
2104          * Update in-memory HEAD object map.
2105          */
2106         rbd_assert(osd_req->r_num_ops == 2);
2107         osd_data = osd_req_op_data(osd_req, 1, cls, request_data);
2108         rbd_assert(osd_data->type == CEPH_OSD_DATA_TYPE_PAGES);
2109 
2110         p = page_address(osd_data->pages[0]);
2111         objno = ceph_decode_64(&p);
2112         rbd_assert(objno == obj_req->ex.oe_objno);
2113         rbd_assert(ceph_decode_64(&p) == objno + 1);
2114         new_state = ceph_decode_8(&p);
2115         has_current_state = ceph_decode_8(&p);
2116         if (has_current_state)
2117                 current_state = ceph_decode_8(&p);
2118 
2119         spin_lock(&rbd_dev->object_map_lock);
2120         state = __rbd_object_map_get(rbd_dev, objno);
2121         if (!has_current_state || current_state == state ||
2122             (current_state == OBJECT_EXISTS && state == OBJECT_EXISTS_CLEAN))
2123                 __rbd_object_map_set(rbd_dev, objno, new_state);
2124         spin_unlock(&rbd_dev->object_map_lock);
2125 
2126         return 0;
2127 }
2128 
2129 static void rbd_object_map_callback(struct ceph_osd_request *osd_req)
2130 {
2131         struct rbd_obj_request *obj_req = osd_req->r_priv;
2132         int result;
2133 
2134         dout("%s osd_req %p result %d for obj_req %p\n", __func__, osd_req,
2135              osd_req->r_result, obj_req);
2136 
2137         result = rbd_object_map_update_finish(obj_req, osd_req);
2138         rbd_obj_handle_request(obj_req, result);
2139 }
2140 
2141 static bool update_needed(struct rbd_device *rbd_dev, u64 objno, u8 new_state)
2142 {
2143         u8 state = rbd_object_map_get(rbd_dev, objno);
2144 
2145         if (state == new_state ||
2146             (new_state == OBJECT_PENDING && state == OBJECT_NONEXISTENT) ||
2147             (new_state == OBJECT_NONEXISTENT && state != OBJECT_PENDING))
2148                 return false;
2149 
2150         return true;
2151 }
2152 
2153 static int rbd_cls_object_map_update(struct ceph_osd_request *req,
2154                                      int which, u64 objno, u8 new_state,
2155                                      const u8 *current_state)
2156 {
2157         struct page **pages;
2158         void *p, *start;
2159         int ret;
2160 
2161         ret = osd_req_op_cls_init(req, which, "rbd", "object_map_update");
2162         if (ret)
2163                 return ret;
2164 
2165         pages = ceph_alloc_page_vector(1, GFP_NOIO);
2166         if (IS_ERR(pages))
2167                 return PTR_ERR(pages);
2168 
2169         p = start = page_address(pages[0]);
2170         ceph_encode_64(&p, objno);
2171         ceph_encode_64(&p, objno + 1);
2172         ceph_encode_8(&p, new_state);
2173         if (current_state) {
2174                 ceph_encode_8(&p, 1);
2175                 ceph_encode_8(&p, *current_state);
2176         } else {
2177                 ceph_encode_8(&p, 0);
2178         }
2179 
2180         osd_req_op_cls_request_data_pages(req, which, pages, p - start, 0,
2181                                           false, true);
2182         return 0;
2183 }
2184 
2185 /*
2186  * Return:
2187  *   0 - object map update sent
2188  *   1 - object map update isn't needed
2189  *  <0 - error
2190  */
2191 static int rbd_object_map_update(struct rbd_obj_request *obj_req, u64 snap_id,
2192                                  u8 new_state, const u8 *current_state)
2193 {
2194         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
2195         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
2196         struct ceph_osd_request *req;
2197         int num_ops = 1;
2198         int which = 0;
2199         int ret;
2200 
2201         if (snap_id == CEPH_NOSNAP) {
2202                 if (!update_needed(rbd_dev, obj_req->ex.oe_objno, new_state))
2203                         return 1;
2204 
2205                 num_ops++; /* assert_locked */
2206         }
2207 
2208         req = ceph_osdc_alloc_request(osdc, NULL, num_ops, false, GFP_NOIO);
2209         if (!req)
2210                 return -ENOMEM;
2211 
2212         list_add_tail(&req->r_private_item, &obj_req->osd_reqs);
2213         req->r_callback = rbd_object_map_callback;
2214         req->r_priv = obj_req;
2215 
2216         rbd_object_map_name(rbd_dev, snap_id, &req->r_base_oid);
2217         ceph_oloc_copy(&req->r_base_oloc, &rbd_dev->header_oloc);
2218         req->r_flags = CEPH_OSD_FLAG_WRITE;
2219         ktime_get_real_ts64(&req->r_mtime);
2220 
2221         if (snap_id == CEPH_NOSNAP) {
2222                 /*
2223                  * Protect against possible race conditions during lock
2224                  * ownership transitions.
2225                  */
2226                 ret = ceph_cls_assert_locked(req, which++, RBD_LOCK_NAME,
2227                                              CEPH_CLS_LOCK_EXCLUSIVE, "", "");
2228                 if (ret)
2229                         return ret;
2230         }
2231 
2232         ret = rbd_cls_object_map_update(req, which, obj_req->ex.oe_objno,
2233                                         new_state, current_state);
2234         if (ret)
2235                 return ret;
2236 
2237         ret = ceph_osdc_alloc_messages(req, GFP_NOIO);
2238         if (ret)
2239                 return ret;
2240 
2241         ceph_osdc_start_request(osdc, req, false);
2242         return 0;
2243 }
2244 
2245 static void prune_extents(struct ceph_file_extent *img_extents,
2246                           u32 *num_img_extents, u64 overlap)
2247 {
2248         u32 cnt = *num_img_extents;
2249 
2250         /* drop extents completely beyond the overlap */
2251         while (cnt && img_extents[cnt - 1].fe_off >= overlap)
2252                 cnt--;
2253 
2254         if (cnt) {
2255                 struct ceph_file_extent *ex = &img_extents[cnt - 1];
2256 
2257                 /* trim final overlapping extent */
2258                 if (ex->fe_off + ex->fe_len > overlap)
2259                         ex->fe_len = overlap - ex->fe_off;
2260         }
2261 
2262         *num_img_extents = cnt;
2263 }
2264 
2265 /*
2266  * Determine the byte range(s) covered by either just the object extent
2267  * or the entire object in the parent image.
2268  */
2269 static int rbd_obj_calc_img_extents(struct rbd_obj_request *obj_req,
2270                                     bool entire)
2271 {
2272         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
2273         int ret;
2274 
2275         if (!rbd_dev->parent_overlap)
2276                 return 0;
2277 
2278         ret = ceph_extent_to_file(&rbd_dev->layout, obj_req->ex.oe_objno,
2279                                   entire ? 0 : obj_req->ex.oe_off,
2280                                   entire ? rbd_dev->layout.object_size :
2281                                                         obj_req->ex.oe_len,
2282                                   &obj_req->img_extents,
2283                                   &obj_req->num_img_extents);
2284         if (ret)
2285                 return ret;
2286 
2287         prune_extents(obj_req->img_extents, &obj_req->num_img_extents,
2288                       rbd_dev->parent_overlap);
2289         return 0;
2290 }
2291 
2292 static void rbd_osd_setup_data(struct ceph_osd_request *osd_req, int which)
2293 {
2294         struct rbd_obj_request *obj_req = osd_req->r_priv;
2295 
2296         switch (obj_req->img_request->data_type) {
2297         case OBJ_REQUEST_BIO:
2298                 osd_req_op_extent_osd_data_bio(osd_req, which,
2299                                                &obj_req->bio_pos,
2300                                                obj_req->ex.oe_len);
2301                 break;
2302         case OBJ_REQUEST_BVECS:
2303         case OBJ_REQUEST_OWN_BVECS:
2304                 rbd_assert(obj_req->bvec_pos.iter.bi_size ==
2305                                                         obj_req->ex.oe_len);
2306                 rbd_assert(obj_req->bvec_idx == obj_req->bvec_count);
2307                 osd_req_op_extent_osd_data_bvec_pos(osd_req, which,
2308                                                     &obj_req->bvec_pos);
2309                 break;
2310         default:
2311                 BUG();
2312         }
2313 }
2314 
2315 static int rbd_osd_setup_stat(struct ceph_osd_request *osd_req, int which)
2316 {
2317         struct page **pages;
2318 
2319         /*
2320          * The response data for a STAT call consists of:
2321          *     le64 length;
2322          *     struct {
2323          *         le32 tv_sec;
2324          *         le32 tv_nsec;
2325          *     } mtime;
2326          */
2327         pages = ceph_alloc_page_vector(1, GFP_NOIO);
2328         if (IS_ERR(pages))
2329                 return PTR_ERR(pages);
2330 
2331         osd_req_op_init(osd_req, which, CEPH_OSD_OP_STAT, 0);
2332         osd_req_op_raw_data_in_pages(osd_req, which, pages,
2333                                      8 + sizeof(struct ceph_timespec),
2334                                      0, false, true);
2335         return 0;
2336 }
2337 
2338 static int rbd_osd_setup_copyup(struct ceph_osd_request *osd_req, int which,
2339                                 u32 bytes)
2340 {
2341         struct rbd_obj_request *obj_req = osd_req->r_priv;
2342         int ret;
2343 
2344         ret = osd_req_op_cls_init(osd_req, which, "rbd", "copyup");
2345         if (ret)
2346                 return ret;
2347 
2348         osd_req_op_cls_request_data_bvecs(osd_req, which, obj_req->copyup_bvecs,
2349                                           obj_req->copyup_bvec_count, bytes);
2350         return 0;
2351 }
2352 
2353 static int rbd_obj_init_read(struct rbd_obj_request *obj_req)
2354 {
2355         obj_req->read_state = RBD_OBJ_READ_START;
2356         return 0;
2357 }
2358 
2359 static void __rbd_osd_setup_write_ops(struct ceph_osd_request *osd_req,
2360                                       int which)
2361 {
2362         struct rbd_obj_request *obj_req = osd_req->r_priv;
2363         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
2364         u16 opcode;
2365 
2366         if (!use_object_map(rbd_dev) ||
2367             !(obj_req->flags & RBD_OBJ_FLAG_MAY_EXIST)) {
2368                 osd_req_op_alloc_hint_init(osd_req, which++,
2369                                            rbd_dev->layout.object_size,
2370                                            rbd_dev->layout.object_size);
2371         }
2372 
2373         if (rbd_obj_is_entire(obj_req))
2374                 opcode = CEPH_OSD_OP_WRITEFULL;
2375         else
2376                 opcode = CEPH_OSD_OP_WRITE;
2377 
2378         osd_req_op_extent_init(osd_req, which, opcode,
2379                                obj_req->ex.oe_off, obj_req->ex.oe_len, 0, 0);
2380         rbd_osd_setup_data(osd_req, which);
2381 }
2382 
2383 static int rbd_obj_init_write(struct rbd_obj_request *obj_req)
2384 {
2385         int ret;
2386 
2387         /* reverse map the entire object onto the parent */
2388         ret = rbd_obj_calc_img_extents(obj_req, true);
2389         if (ret)
2390                 return ret;
2391 
2392         if (rbd_obj_copyup_enabled(obj_req))
2393                 obj_req->flags |= RBD_OBJ_FLAG_COPYUP_ENABLED;
2394 
2395         obj_req->write_state = RBD_OBJ_WRITE_START;
2396         return 0;
2397 }
2398 
2399 static u16 truncate_or_zero_opcode(struct rbd_obj_request *obj_req)
2400 {
2401         return rbd_obj_is_tail(obj_req) ? CEPH_OSD_OP_TRUNCATE :
2402                                           CEPH_OSD_OP_ZERO;
2403 }
2404 
2405 static void __rbd_osd_setup_discard_ops(struct ceph_osd_request *osd_req,
2406                                         int which)
2407 {
2408         struct rbd_obj_request *obj_req = osd_req->r_priv;
2409 
2410         if (rbd_obj_is_entire(obj_req) && !obj_req->num_img_extents) {
2411                 rbd_assert(obj_req->flags & RBD_OBJ_FLAG_DELETION);
2412                 osd_req_op_init(osd_req, which, CEPH_OSD_OP_DELETE, 0);
2413         } else {
2414                 osd_req_op_extent_init(osd_req, which,
2415                                        truncate_or_zero_opcode(obj_req),
2416                                        obj_req->ex.oe_off, obj_req->ex.oe_len,
2417                                        0, 0);
2418         }
2419 }
2420 
2421 static int rbd_obj_init_discard(struct rbd_obj_request *obj_req)
2422 {
2423         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
2424         u64 off, next_off;
2425         int ret;
2426 
2427         /*
2428          * Align the range to alloc_size boundary and punt on discards
2429          * that are too small to free up any space.
2430          *
2431          * alloc_size == object_size && is_tail() is a special case for
2432          * filestore with filestore_punch_hole = false, needed to allow
2433          * truncate (in addition to delete).
2434          */
2435         if (rbd_dev->opts->alloc_size != rbd_dev->layout.object_size ||
2436             !rbd_obj_is_tail(obj_req)) {
2437                 off = round_up(obj_req->ex.oe_off, rbd_dev->opts->alloc_size);
2438                 next_off = round_down(obj_req->ex.oe_off + obj_req->ex.oe_len,
2439                                       rbd_dev->opts->alloc_size);
2440                 if (off >= next_off)
2441                         return 1;
2442 
2443                 dout("%s %p %llu~%llu -> %llu~%llu\n", __func__,
2444                      obj_req, obj_req->ex.oe_off, obj_req->ex.oe_len,
2445                      off, next_off - off);
2446                 obj_req->ex.oe_off = off;
2447                 obj_req->ex.oe_len = next_off - off;
2448         }
2449 
2450         /* reverse map the entire object onto the parent */
2451         ret = rbd_obj_calc_img_extents(obj_req, true);
2452         if (ret)
2453                 return ret;
2454 
2455         obj_req->flags |= RBD_OBJ_FLAG_NOOP_FOR_NONEXISTENT;
2456         if (rbd_obj_is_entire(obj_req) && !obj_req->num_img_extents)
2457                 obj_req->flags |= RBD_OBJ_FLAG_DELETION;
2458 
2459         obj_req->write_state = RBD_OBJ_WRITE_START;
2460         return 0;
2461 }
2462 
2463 static void __rbd_osd_setup_zeroout_ops(struct ceph_osd_request *osd_req,
2464                                         int which)
2465 {
2466         struct rbd_obj_request *obj_req = osd_req->r_priv;
2467         u16 opcode;
2468 
2469         if (rbd_obj_is_entire(obj_req)) {
2470                 if (obj_req->num_img_extents) {
2471                         if (!(obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED))
2472                                 osd_req_op_init(osd_req, which++,
2473                                                 CEPH_OSD_OP_CREATE, 0);
2474                         opcode = CEPH_OSD_OP_TRUNCATE;
2475                 } else {
2476                         rbd_assert(obj_req->flags & RBD_OBJ_FLAG_DELETION);
2477                         osd_req_op_init(osd_req, which++,
2478                                         CEPH_OSD_OP_DELETE, 0);
2479                         opcode = 0;
2480                 }
2481         } else {
2482                 opcode = truncate_or_zero_opcode(obj_req);
2483         }
2484 
2485         if (opcode)
2486                 osd_req_op_extent_init(osd_req, which, opcode,
2487                                        obj_req->ex.oe_off, obj_req->ex.oe_len,
2488                                        0, 0);
2489 }
2490 
2491 static int rbd_obj_init_zeroout(struct rbd_obj_request *obj_req)
2492 {
2493         int ret;
2494 
2495         /* reverse map the entire object onto the parent */
2496         ret = rbd_obj_calc_img_extents(obj_req, true);
2497         if (ret)
2498                 return ret;
2499 
2500         if (rbd_obj_copyup_enabled(obj_req))
2501                 obj_req->flags |= RBD_OBJ_FLAG_COPYUP_ENABLED;
2502         if (!obj_req->num_img_extents) {
2503                 obj_req->flags |= RBD_OBJ_FLAG_NOOP_FOR_NONEXISTENT;
2504                 if (rbd_obj_is_entire(obj_req))
2505                         obj_req->flags |= RBD_OBJ_FLAG_DELETION;
2506         }
2507 
2508         obj_req->write_state = RBD_OBJ_WRITE_START;
2509         return 0;
2510 }
2511 
2512 static int count_write_ops(struct rbd_obj_request *obj_req)
2513 {
2514         struct rbd_img_request *img_req = obj_req->img_request;
2515 
2516         switch (img_req->op_type) {
2517         case OBJ_OP_WRITE:
2518                 if (!use_object_map(img_req->rbd_dev) ||
2519                     !(obj_req->flags & RBD_OBJ_FLAG_MAY_EXIST))
2520                         return 2; /* setallochint + write/writefull */
2521 
2522                 return 1; /* write/writefull */
2523         case OBJ_OP_DISCARD:
2524                 return 1; /* delete/truncate/zero */
2525         case OBJ_OP_ZEROOUT:
2526                 if (rbd_obj_is_entire(obj_req) && obj_req->num_img_extents &&
2527                     !(obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED))
2528                         return 2; /* create + truncate */
2529 
2530                 return 1; /* delete/truncate/zero */
2531         default:
2532                 BUG();
2533         }
2534 }
2535 
2536 static void rbd_osd_setup_write_ops(struct ceph_osd_request *osd_req,
2537                                     int which)
2538 {
2539         struct rbd_obj_request *obj_req = osd_req->r_priv;
2540 
2541         switch (obj_req->img_request->op_type) {
2542         case OBJ_OP_WRITE:
2543                 __rbd_osd_setup_write_ops(osd_req, which);
2544                 break;
2545         case OBJ_OP_DISCARD:
2546                 __rbd_osd_setup_discard_ops(osd_req, which);
2547                 break;
2548         case OBJ_OP_ZEROOUT:
2549                 __rbd_osd_setup_zeroout_ops(osd_req, which);
2550                 break;
2551         default:
2552                 BUG();
2553         }
2554 }
2555 
2556 /*
2557  * Prune the list of object requests (adjust offset and/or length, drop
2558  * redundant requests).  Prepare object request state machines and image
2559  * request state machine for execution.
2560  */
2561 static int __rbd_img_fill_request(struct rbd_img_request *img_req)
2562 {
2563         struct rbd_obj_request *obj_req, *next_obj_req;
2564         int ret;
2565 
2566         for_each_obj_request_safe(img_req, obj_req, next_obj_req) {
2567                 switch (img_req->op_type) {
2568                 case OBJ_OP_READ:
2569                         ret = rbd_obj_init_read(obj_req);
2570                         break;
2571                 case OBJ_OP_WRITE:
2572                         ret = rbd_obj_init_write(obj_req);
2573                         break;
2574                 case OBJ_OP_DISCARD:
2575                         ret = rbd_obj_init_discard(obj_req);
2576                         break;
2577                 case OBJ_OP_ZEROOUT:
2578                         ret = rbd_obj_init_zeroout(obj_req);
2579                         break;
2580                 default:
2581                         BUG();
2582                 }
2583                 if (ret < 0)
2584                         return ret;
2585                 if (ret > 0) {
2586                         rbd_img_obj_request_del(img_req, obj_req);
2587                         continue;
2588                 }
2589         }
2590 
2591         img_req->state = RBD_IMG_START;
2592         return 0;
2593 }
2594 
2595 union rbd_img_fill_iter {
2596         struct ceph_bio_iter    bio_iter;
2597         struct ceph_bvec_iter   bvec_iter;
2598 };
2599 
2600 struct rbd_img_fill_ctx {
2601         enum obj_request_type   pos_type;
2602         union rbd_img_fill_iter *pos;
2603         union rbd_img_fill_iter iter;
2604         ceph_object_extent_fn_t set_pos_fn;
2605         ceph_object_extent_fn_t count_fn;
2606         ceph_object_extent_fn_t copy_fn;
2607 };
2608 
2609 static struct ceph_object_extent *alloc_object_extent(void *arg)
2610 {
2611         struct rbd_img_request *img_req = arg;
2612         struct rbd_obj_request *obj_req;
2613 
2614         obj_req = rbd_obj_request_create();
2615         if (!obj_req)
2616                 return NULL;
2617 
2618         rbd_img_obj_request_add(img_req, obj_req);
2619         return &obj_req->ex;
2620 }
2621 
2622 /*
2623  * While su != os && sc == 1 is technically not fancy (it's the same
2624  * layout as su == os && sc == 1), we can't use the nocopy path for it
2625  * because ->set_pos_fn() should be called only once per object.
2626  * ceph_file_to_extents() invokes action_fn once per stripe unit, so
2627  * treat su != os && sc == 1 as fancy.
2628  */
2629 static bool rbd_layout_is_fancy(struct ceph_file_layout *l)
2630 {
2631         return l->stripe_unit != l->object_size;
2632 }
2633 
2634 static int rbd_img_fill_request_nocopy(struct rbd_img_request *img_req,
2635                                        struct ceph_file_extent *img_extents,
2636                                        u32 num_img_extents,
2637                                        struct rbd_img_fill_ctx *fctx)
2638 {
2639         u32 i;
2640         int ret;
2641 
2642         img_req->data_type = fctx->pos_type;
2643 
2644         /*
2645          * Create object requests and set each object request's starting
2646          * position in the provided bio (list) or bio_vec array.
2647          */
2648         fctx->iter = *fctx->pos;
2649         for (i = 0; i < num_img_extents; i++) {
2650                 ret = ceph_file_to_extents(&img_req->rbd_dev->layout,
2651                                            img_extents[i].fe_off,
2652                                            img_extents[i].fe_len,
2653                                            &img_req->object_extents,
2654                                            alloc_object_extent, img_req,
2655                                            fctx->set_pos_fn, &fctx->iter);
2656                 if (ret)
2657                         return ret;
2658         }
2659 
2660         return __rbd_img_fill_request(img_req);
2661 }
2662 
2663 /*
2664  * Map a list of image extents to a list of object extents, create the
2665  * corresponding object requests (normally each to a different object,
2666  * but not always) and add them to @img_req.  For each object request,
2667  * set up its data descriptor to point to the corresponding chunk(s) of
2668  * @fctx->pos data buffer.
2669  *
2670  * Because ceph_file_to_extents() will merge adjacent object extents
2671  * together, each object request's data descriptor may point to multiple
2672  * different chunks of @fctx->pos data buffer.
2673  *
2674  * @fctx->pos data buffer is assumed to be large enough.
2675  */
2676 static int rbd_img_fill_request(struct rbd_img_request *img_req,
2677                                 struct ceph_file_extent *img_extents,
2678                                 u32 num_img_extents,
2679                                 struct rbd_img_fill_ctx *fctx)
2680 {
2681         struct rbd_device *rbd_dev = img_req->rbd_dev;
2682         struct rbd_obj_request *obj_req;
2683         u32 i;
2684         int ret;
2685 
2686         if (fctx->pos_type == OBJ_REQUEST_NODATA ||
2687             !rbd_layout_is_fancy(&rbd_dev->layout))
2688                 return rbd_img_fill_request_nocopy(img_req, img_extents,
2689                                                    num_img_extents, fctx);
2690 
2691         img_req->data_type = OBJ_REQUEST_OWN_BVECS;
2692 
2693         /*
2694          * Create object requests and determine ->bvec_count for each object
2695          * request.  Note that ->bvec_count sum over all object requests may
2696          * be greater than the number of bio_vecs in the provided bio (list)
2697          * or bio_vec array because when mapped, those bio_vecs can straddle
2698          * stripe unit boundaries.
2699          */
2700         fctx->iter = *fctx->pos;
2701         for (i = 0; i < num_img_extents; i++) {
2702                 ret = ceph_file_to_extents(&rbd_dev->layout,
2703                                            img_extents[i].fe_off,
2704                                            img_extents[i].fe_len,
2705                                            &img_req->object_extents,
2706                                            alloc_object_extent, img_req,
2707                                            fctx->count_fn, &fctx->iter);
2708                 if (ret)
2709                         return ret;
2710         }
2711 
2712         for_each_obj_request(img_req, obj_req) {
2713                 obj_req->bvec_pos.bvecs = kmalloc_array(obj_req->bvec_count,
2714                                               sizeof(*obj_req->bvec_pos.bvecs),
2715                                               GFP_NOIO);
2716                 if (!obj_req->bvec_pos.bvecs)
2717                         return -ENOMEM;
2718         }
2719 
2720         /*
2721          * Fill in each object request's private bio_vec array, splitting and
2722          * rearranging the provided bio_vecs in stripe unit chunks as needed.
2723          */
2724         fctx->iter = *fctx->pos;
2725         for (i = 0; i < num_img_extents; i++) {
2726                 ret = ceph_iterate_extents(&rbd_dev->layout,
2727                                            img_extents[i].fe_off,
2728                                            img_extents[i].fe_len,
2729                                            &img_req->object_extents,
2730                                            fctx->copy_fn, &fctx->iter);
2731                 if (ret)
2732                         return ret;
2733         }
2734 
2735         return __rbd_img_fill_request(img_req);
2736 }
2737 
2738 static int rbd_img_fill_nodata(struct rbd_img_request *img_req,
2739                                u64 off, u64 len)
2740 {
2741         struct ceph_file_extent ex = { off, len };
2742         union rbd_img_fill_iter dummy = {};
2743         struct rbd_img_fill_ctx fctx = {
2744                 .pos_type = OBJ_REQUEST_NODATA,
2745                 .pos = &dummy,
2746         };
2747 
2748         return rbd_img_fill_request(img_req, &ex, 1, &fctx);
2749 }
2750 
2751 static void set_bio_pos(struct ceph_object_extent *ex, u32 bytes, void *arg)
2752 {
2753         struct rbd_obj_request *obj_req =
2754             container_of(ex, struct rbd_obj_request, ex);
2755         struct ceph_bio_iter *it = arg;
2756 
2757         dout("%s objno %llu bytes %u\n", __func__, ex->oe_objno, bytes);
2758         obj_req->bio_pos = *it;
2759         ceph_bio_iter_advance(it, bytes);
2760 }
2761 
2762 static void count_bio_bvecs(struct ceph_object_extent *ex, u32 bytes, void *arg)
2763 {
2764         struct rbd_obj_request *obj_req =
2765             container_of(ex, struct rbd_obj_request, ex);
2766         struct ceph_bio_iter *it = arg;
2767 
2768         dout("%s objno %llu bytes %u\n", __func__, ex->oe_objno, bytes);
2769         ceph_bio_iter_advance_step(it, bytes, ({
2770                 obj_req->bvec_count++;
2771         }));
2772 
2773 }
2774 
2775 static void copy_bio_bvecs(struct ceph_object_extent *ex, u32 bytes, void *arg)
2776 {
2777         struct rbd_obj_request *obj_req =
2778             container_of(ex, struct rbd_obj_request, ex);
2779         struct ceph_bio_iter *it = arg;
2780 
2781         dout("%s objno %llu bytes %u\n", __func__, ex->oe_objno, bytes);
2782         ceph_bio_iter_advance_step(it, bytes, ({
2783                 obj_req->bvec_pos.bvecs[obj_req->bvec_idx++] = bv;
2784                 obj_req->bvec_pos.iter.bi_size += bv.bv_len;
2785         }));
2786 }
2787 
2788 static int __rbd_img_fill_from_bio(struct rbd_img_request *img_req,
2789                                    struct ceph_file_extent *img_extents,
2790                                    u32 num_img_extents,
2791                                    struct ceph_bio_iter *bio_pos)
2792 {
2793         struct rbd_img_fill_ctx fctx = {
2794                 .pos_type = OBJ_REQUEST_BIO,
2795                 .pos = (union rbd_img_fill_iter *)bio_pos,
2796                 .set_pos_fn = set_bio_pos,
2797                 .count_fn = count_bio_bvecs,
2798                 .copy_fn = copy_bio_bvecs,
2799         };
2800 
2801         return rbd_img_fill_request(img_req, img_extents, num_img_extents,
2802                                     &fctx);
2803 }
2804 
2805 static int rbd_img_fill_from_bio(struct rbd_img_request *img_req,
2806                                  u64 off, u64 len, struct bio *bio)
2807 {
2808         struct ceph_file_extent ex = { off, len };
2809         struct ceph_bio_iter it = { .bio = bio, .iter = bio->bi_iter };
2810 
2811         return __rbd_img_fill_from_bio(img_req, &ex, 1, &it);
2812 }
2813 
2814 static void set_bvec_pos(struct ceph_object_extent *ex, u32 bytes, void *arg)
2815 {
2816         struct rbd_obj_request *obj_req =
2817             container_of(ex, struct rbd_obj_request, ex);
2818         struct ceph_bvec_iter *it = arg;
2819 
2820         obj_req->bvec_pos = *it;
2821         ceph_bvec_iter_shorten(&obj_req->bvec_pos, bytes);
2822         ceph_bvec_iter_advance(it, bytes);
2823 }
2824 
2825 static void count_bvecs(struct ceph_object_extent *ex, u32 bytes, void *arg)
2826 {
2827         struct rbd_obj_request *obj_req =
2828             container_of(ex, struct rbd_obj_request, ex);
2829         struct ceph_bvec_iter *it = arg;
2830 
2831         ceph_bvec_iter_advance_step(it, bytes, ({
2832                 obj_req->bvec_count++;
2833         }));
2834 }
2835 
2836 static void copy_bvecs(struct ceph_object_extent *ex, u32 bytes, void *arg)
2837 {
2838         struct rbd_obj_request *obj_req =
2839             container_of(ex, struct rbd_obj_request, ex);
2840         struct ceph_bvec_iter *it = arg;
2841 
2842         ceph_bvec_iter_advance_step(it, bytes, ({
2843                 obj_req->bvec_pos.bvecs[obj_req->bvec_idx++] = bv;
2844                 obj_req->bvec_pos.iter.bi_size += bv.bv_len;
2845         }));
2846 }
2847 
2848 static int __rbd_img_fill_from_bvecs(struct rbd_img_request *img_req,
2849                                      struct ceph_file_extent *img_extents,
2850                                      u32 num_img_extents,
2851                                      struct ceph_bvec_iter *bvec_pos)
2852 {
2853         struct rbd_img_fill_ctx fctx = {
2854                 .pos_type = OBJ_REQUEST_BVECS,
2855                 .pos = (union rbd_img_fill_iter *)bvec_pos,
2856                 .set_pos_fn = set_bvec_pos,
2857                 .count_fn = count_bvecs,
2858                 .copy_fn = copy_bvecs,
2859         };
2860 
2861         return rbd_img_fill_request(img_req, img_extents, num_img_extents,
2862                                     &fctx);
2863 }
2864 
2865 static int rbd_img_fill_from_bvecs(struct rbd_img_request *img_req,
2866                                    struct ceph_file_extent *img_extents,
2867                                    u32 num_img_extents,
2868                                    struct bio_vec *bvecs)
2869 {
2870         struct ceph_bvec_iter it = {
2871                 .bvecs = bvecs,
2872                 .iter = { .bi_size = ceph_file_extents_bytes(img_extents,
2873                                                              num_img_extents) },
2874         };
2875 
2876         return __rbd_img_fill_from_bvecs(img_req, img_extents, num_img_extents,
2877                                          &it);
2878 }
2879 
2880 static void rbd_img_handle_request_work(struct work_struct *work)
2881 {
2882         struct rbd_img_request *img_req =
2883             container_of(work, struct rbd_img_request, work);
2884 
2885         rbd_img_handle_request(img_req, img_req->work_result);
2886 }
2887 
2888 static void rbd_img_schedule(struct rbd_img_request *img_req, int result)
2889 {
2890         INIT_WORK(&img_req->work, rbd_img_handle_request_work);
2891         img_req->work_result = result;
2892         queue_work(rbd_wq, &img_req->work);
2893 }
2894 
2895 static bool rbd_obj_may_exist(struct rbd_obj_request *obj_req)
2896 {
2897         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
2898 
2899         if (rbd_object_map_may_exist(rbd_dev, obj_req->ex.oe_objno)) {
2900                 obj_req->flags |= RBD_OBJ_FLAG_MAY_EXIST;
2901                 return true;
2902         }
2903 
2904         dout("%s %p objno %llu assuming dne\n", __func__, obj_req,
2905              obj_req->ex.oe_objno);
2906         return false;
2907 }
2908 
2909 static int rbd_obj_read_object(struct rbd_obj_request *obj_req)
2910 {
2911         struct ceph_osd_request *osd_req;
2912         int ret;
2913 
2914         osd_req = __rbd_obj_add_osd_request(obj_req, NULL, 1);
2915         if (IS_ERR(osd_req))
2916                 return PTR_ERR(osd_req);
2917 
2918         osd_req_op_extent_init(osd_req, 0, CEPH_OSD_OP_READ,
2919                                obj_req->ex.oe_off, obj_req->ex.oe_len, 0, 0);
2920         rbd_osd_setup_data(osd_req, 0);
2921         rbd_osd_format_read(osd_req);
2922 
2923         ret = ceph_osdc_alloc_messages(osd_req, GFP_NOIO);
2924         if (ret)
2925                 return ret;
2926 
2927         rbd_osd_submit(osd_req);
2928         return 0;
2929 }
2930 
2931 static int rbd_obj_read_from_parent(struct rbd_obj_request *obj_req)
2932 {
2933         struct rbd_img_request *img_req = obj_req->img_request;
2934         struct rbd_img_request *child_img_req;
2935         int ret;
2936 
2937         child_img_req = rbd_img_request_create(img_req->rbd_dev->parent,
2938                                                OBJ_OP_READ, NULL);
2939         if (!child_img_req)
2940                 return -ENOMEM;
2941 
2942         __set_bit(IMG_REQ_CHILD, &child_img_req->flags);
2943         child_img_req->obj_request = obj_req;
2944 
2945         dout("%s child_img_req %p for obj_req %p\n", __func__, child_img_req,
2946              obj_req);
2947 
2948         if (!rbd_img_is_write(img_req)) {
2949                 switch (img_req->data_type) {
2950                 case OBJ_REQUEST_BIO:
2951                         ret = __rbd_img_fill_from_bio(child_img_req,
2952                                                       obj_req->img_extents,
2953                                                       obj_req->num_img_extents,
2954                                                       &obj_req->bio_pos);
2955                         break;
2956                 case OBJ_REQUEST_BVECS:
2957                 case OBJ_REQUEST_OWN_BVECS:
2958                         ret = __rbd_img_fill_from_bvecs(child_img_req,
2959                                                       obj_req->img_extents,
2960                                                       obj_req->num_img_extents,
2961                                                       &obj_req->bvec_pos);
2962                         break;
2963                 default:
2964                         BUG();
2965                 }
2966         } else {
2967                 ret = rbd_img_fill_from_bvecs(child_img_req,
2968                                               obj_req->img_extents,
2969                                               obj_req->num_img_extents,
2970                                               obj_req->copyup_bvecs);
2971         }
2972         if (ret) {
2973                 rbd_img_request_put(child_img_req);
2974                 return ret;
2975         }
2976 
2977         /* avoid parent chain recursion */
2978         rbd_img_schedule(child_img_req, 0);
2979         return 0;
2980 }
2981 
2982 static bool rbd_obj_advance_read(struct rbd_obj_request *obj_req, int *result)
2983 {
2984         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
2985         int ret;
2986 
2987 again:
2988         switch (obj_req->read_state) {
2989         case RBD_OBJ_READ_START:
2990                 rbd_assert(!*result);
2991 
2992                 if (!rbd_obj_may_exist(obj_req)) {
2993                         *result = -ENOENT;
2994                         obj_req->read_state = RBD_OBJ_READ_OBJECT;
2995                         goto again;
2996                 }
2997 
2998                 ret = rbd_obj_read_object(obj_req);
2999                 if (ret) {
3000                         *result = ret;
3001                         return true;
3002                 }
3003                 obj_req->read_state = RBD_OBJ_READ_OBJECT;
3004                 return false;
3005         case RBD_OBJ_READ_OBJECT:
3006                 if (*result == -ENOENT && rbd_dev->parent_overlap) {
3007                         /* reverse map this object extent onto the parent */
3008                         ret = rbd_obj_calc_img_extents(obj_req, false);
3009                         if (ret) {
3010                                 *result = ret;
3011                                 return true;
3012                         }
3013                         if (obj_req->num_img_extents) {
3014                                 ret = rbd_obj_read_from_parent(obj_req);
3015                                 if (ret) {
3016                                         *result = ret;
3017                                         return true;
3018                                 }
3019                                 obj_req->read_state = RBD_OBJ_READ_PARENT;
3020                                 return false;
3021                         }
3022                 }
3023 
3024                 /*
3025                  * -ENOENT means a hole in the image -- zero-fill the entire
3026                  * length of the request.  A short read also implies zero-fill
3027                  * to the end of the request.
3028                  */
3029                 if (*result == -ENOENT) {
3030                         rbd_obj_zero_range(obj_req, 0, obj_req->ex.oe_len);
3031                         *result = 0;
3032                 } else if (*result >= 0) {
3033                         if (*result < obj_req->ex.oe_len)
3034                                 rbd_obj_zero_range(obj_req, *result,
3035                                                 obj_req->ex.oe_len - *result);
3036                         else
3037                                 rbd_assert(*result == obj_req->ex.oe_len);
3038                         *result = 0;
3039                 }
3040                 return true;
3041         case RBD_OBJ_READ_PARENT:
3042                 /*
3043                  * The parent image is read only up to the overlap -- zero-fill
3044                  * from the overlap to the end of the request.
3045                  */
3046                 if (!*result) {
3047                         u32 obj_overlap = rbd_obj_img_extents_bytes(obj_req);
3048 
3049                         if (obj_overlap < obj_req->ex.oe_len)
3050                                 rbd_obj_zero_range(obj_req, obj_overlap,
3051                                             obj_req->ex.oe_len - obj_overlap);
3052                 }
3053                 return true;
3054         default:
3055                 BUG();
3056         }
3057 }
3058 
3059 static bool rbd_obj_write_is_noop(struct rbd_obj_request *obj_req)
3060 {
3061         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
3062 
3063         if (rbd_object_map_may_exist(rbd_dev, obj_req->ex.oe_objno))
3064                 obj_req->flags |= RBD_OBJ_FLAG_MAY_EXIST;
3065 
3066         if (!(obj_req->flags & RBD_OBJ_FLAG_MAY_EXIST) &&
3067             (obj_req->flags & RBD_OBJ_FLAG_NOOP_FOR_NONEXISTENT)) {
3068                 dout("%s %p noop for nonexistent\n", __func__, obj_req);
3069                 return true;
3070         }
3071 
3072         return false;
3073 }
3074 
3075 /*
3076  * Return:
3077  *   0 - object map update sent
3078  *   1 - object map update isn't needed
3079  *  <0 - error
3080  */
3081 static int rbd_obj_write_pre_object_map(struct rbd_obj_request *obj_req)
3082 {
3083         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
3084         u8 new_state;
3085 
3086         if (!(rbd_dev->header.features & RBD_FEATURE_OBJECT_MAP))
3087                 return 1;
3088 
3089         if (obj_req->flags & RBD_OBJ_FLAG_DELETION)
3090                 new_state = OBJECT_PENDING;
3091         else
3092                 new_state = OBJECT_EXISTS;
3093 
3094         return rbd_object_map_update(obj_req, CEPH_NOSNAP, new_state, NULL);
3095 }
3096 
3097 static int rbd_obj_write_object(struct rbd_obj_request *obj_req)
3098 {
3099         struct ceph_osd_request *osd_req;
3100         int num_ops = count_write_ops(obj_req);
3101         int which = 0;
3102         int ret;
3103 
3104         if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED)
3105                 num_ops++; /* stat */
3106 
3107         osd_req = rbd_obj_add_osd_request(obj_req, num_ops);
3108         if (IS_ERR(osd_req))
3109                 return PTR_ERR(osd_req);
3110 
3111         if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED) {
3112                 ret = rbd_osd_setup_stat(osd_req, which++);
3113                 if (ret)
3114                         return ret;
3115         }
3116 
3117         rbd_osd_setup_write_ops(osd_req, which);
3118         rbd_osd_format_write(osd_req);
3119 
3120         ret = ceph_osdc_alloc_messages(osd_req, GFP_NOIO);
3121         if (ret)
3122                 return ret;
3123 
3124         rbd_osd_submit(osd_req);
3125         return 0;
3126 }
3127 
3128 /*
3129  * copyup_bvecs pages are never highmem pages
3130  */
3131 static bool is_zero_bvecs(struct bio_vec *bvecs, u32 bytes)
3132 {
3133         struct ceph_bvec_iter it = {
3134                 .bvecs = bvecs,
3135                 .iter = { .bi_size = bytes },
3136         };
3137 
3138         ceph_bvec_iter_advance_step(&it, bytes, ({
3139                 if (memchr_inv(page_address(bv.bv_page) + bv.bv_offset, 0,
3140                                bv.bv_len))
3141                         return false;
3142         }));
3143         return true;
3144 }
3145 
3146 #define MODS_ONLY       U32_MAX
3147 
3148 static int rbd_obj_copyup_empty_snapc(struct rbd_obj_request *obj_req,
3149                                       u32 bytes)
3150 {
3151         struct ceph_osd_request *osd_req;
3152         int ret;
3153 
3154         dout("%s obj_req %p bytes %u\n", __func__, obj_req, bytes);
3155         rbd_assert(bytes > 0 && bytes != MODS_ONLY);
3156 
3157         osd_req = __rbd_obj_add_osd_request(obj_req, &rbd_empty_snapc, 1);
3158         if (IS_ERR(osd_req))
3159                 return PTR_ERR(osd_req);
3160 
3161         ret = rbd_osd_setup_copyup(osd_req, 0, bytes);
3162         if (ret)
3163                 return ret;
3164 
3165         rbd_osd_format_write(osd_req);
3166 
3167         ret = ceph_osdc_alloc_messages(osd_req, GFP_NOIO);
3168         if (ret)
3169                 return ret;
3170 
3171         rbd_osd_submit(osd_req);
3172         return 0;
3173 }
3174 
3175 static int rbd_obj_copyup_current_snapc(struct rbd_obj_request *obj_req,
3176                                         u32 bytes)
3177 {
3178         struct ceph_osd_request *osd_req;
3179         int num_ops = count_write_ops(obj_req);
3180         int which = 0;
3181         int ret;
3182 
3183         dout("%s obj_req %p bytes %u\n", __func__, obj_req, bytes);
3184 
3185         if (bytes != MODS_ONLY)
3186                 num_ops++; /* copyup */
3187 
3188         osd_req = rbd_obj_add_osd_request(obj_req, num_ops);
3189         if (IS_ERR(osd_req))
3190                 return PTR_ERR(osd_req);
3191 
3192         if (bytes != MODS_ONLY) {
3193                 ret = rbd_osd_setup_copyup(osd_req, which++, bytes);
3194                 if (ret)
3195                         return ret;
3196         }
3197 
3198         rbd_osd_setup_write_ops(osd_req, which);
3199         rbd_osd_format_write(osd_req);
3200 
3201         ret = ceph_osdc_alloc_messages(osd_req, GFP_NOIO);
3202         if (ret)
3203                 return ret;
3204 
3205         rbd_osd_submit(osd_req);
3206         return 0;
3207 }
3208 
3209 static int setup_copyup_bvecs(struct rbd_obj_request *obj_req, u64 obj_overlap)
3210 {
3211         u32 i;
3212 
3213         rbd_assert(!obj_req->copyup_bvecs);
3214         obj_req->copyup_bvec_count = calc_pages_for(0, obj_overlap);
3215         obj_req->copyup_bvecs = kcalloc(obj_req->copyup_bvec_count,
3216                                         sizeof(*obj_req->copyup_bvecs),
3217                                         GFP_NOIO);
3218         if (!obj_req->copyup_bvecs)
3219                 return -ENOMEM;
3220 
3221         for (i = 0; i < obj_req->copyup_bvec_count; i++) {
3222                 unsigned int len = min(obj_overlap, (u64)PAGE_SIZE);
3223 
3224                 obj_req->copyup_bvecs[i].bv_page = alloc_page(GFP_NOIO);
3225                 if (!obj_req->copyup_bvecs[i].bv_page)
3226                         return -ENOMEM;
3227 
3228                 obj_req->copyup_bvecs[i].bv_offset = 0;
3229                 obj_req->copyup_bvecs[i].bv_len = len;
3230                 obj_overlap -= len;
3231         }
3232 
3233         rbd_assert(!obj_overlap);
3234         return 0;
3235 }
3236 
3237 /*
3238  * The target object doesn't exist.  Read the data for the entire
3239  * target object up to the overlap point (if any) from the parent,
3240  * so we can use it for a copyup.
3241  */
3242 static int rbd_obj_copyup_read_parent(struct rbd_obj_request *obj_req)
3243 {
3244         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
3245         int ret;
3246 
3247         rbd_assert(obj_req->num_img_extents);
3248         prune_extents(obj_req->img_extents, &obj_req->num_img_extents,
3249                       rbd_dev->parent_overlap);
3250         if (!obj_req->num_img_extents) {
3251                 /*
3252                  * The overlap has become 0 (most likely because the
3253                  * image has been flattened).  Re-submit the original write
3254                  * request -- pass MODS_ONLY since the copyup isn't needed
3255                  * anymore.
3256                  */
3257                 return rbd_obj_copyup_current_snapc(obj_req, MODS_ONLY);
3258         }
3259 
3260         ret = setup_copyup_bvecs(obj_req, rbd_obj_img_extents_bytes(obj_req));
3261         if (ret)
3262                 return ret;
3263 
3264         return rbd_obj_read_from_parent(obj_req);
3265 }
3266 
3267 static void rbd_obj_copyup_object_maps(struct rbd_obj_request *obj_req)
3268 {
3269         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
3270         struct ceph_snap_context *snapc = obj_req->img_request->snapc;
3271         u8 new_state;
3272         u32 i;
3273         int ret;
3274 
3275         rbd_assert(!obj_req->pending.result && !obj_req->pending.num_pending);
3276 
3277         if (!(rbd_dev->header.features & RBD_FEATURE_OBJECT_MAP))
3278                 return;
3279 
3280         if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ZEROS)
3281                 return;
3282 
3283         for (i = 0; i < snapc->num_snaps; i++) {
3284                 if ((rbd_dev->header.features & RBD_FEATURE_FAST_DIFF) &&
3285                     i + 1 < snapc->num_snaps)
3286                         new_state = OBJECT_EXISTS_CLEAN;
3287                 else
3288                         new_state = OBJECT_EXISTS;
3289 
3290                 ret = rbd_object_map_update(obj_req, snapc->snaps[i],
3291                                             new_state, NULL);
3292                 if (ret < 0) {
3293                         obj_req->pending.result = ret;
3294                         return;
3295                 }
3296 
3297                 rbd_assert(!ret);
3298                 obj_req->pending.num_pending++;
3299         }
3300 }
3301 
3302 static void rbd_obj_copyup_write_object(struct rbd_obj_request *obj_req)
3303 {
3304         u32 bytes = rbd_obj_img_extents_bytes(obj_req);
3305         int ret;
3306 
3307         rbd_assert(!obj_req->pending.result && !obj_req->pending.num_pending);
3308 
3309         /*
3310          * Only send non-zero copyup data to save some I/O and network
3311          * bandwidth -- zero copyup data is equivalent to the object not
3312          * existing.
3313          */
3314         if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ZEROS)
3315                 bytes = 0;
3316 
3317         if (obj_req->img_request->snapc->num_snaps && bytes > 0) {
3318                 /*
3319                  * Send a copyup request with an empty snapshot context to
3320                  * deep-copyup the object through all existing snapshots.
3321                  * A second request with the current snapshot context will be
3322                  * sent for the actual modification.
3323                  */
3324                 ret = rbd_obj_copyup_empty_snapc(obj_req, bytes);
3325                 if (ret) {
3326                         obj_req->pending.result = ret;
3327                         return;
3328                 }
3329 
3330                 obj_req->pending.num_pending++;
3331                 bytes = MODS_ONLY;
3332         }
3333 
3334         ret = rbd_obj_copyup_current_snapc(obj_req, bytes);
3335         if (ret) {
3336                 obj_req->pending.result = ret;
3337                 return;
3338         }
3339 
3340         obj_req->pending.num_pending++;
3341 }
3342 
3343 static bool rbd_obj_advance_copyup(struct rbd_obj_request *obj_req, int *result)
3344 {
3345         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
3346         int ret;
3347 
3348 again:
3349         switch (obj_req->copyup_state) {
3350         case RBD_OBJ_COPYUP_START:
3351                 rbd_assert(!*result);
3352 
3353                 ret = rbd_obj_copyup_read_parent(obj_req);
3354                 if (ret) {
3355                         *result = ret;
3356                         return true;
3357                 }
3358                 if (obj_req->num_img_extents)
3359                         obj_req->copyup_state = RBD_OBJ_COPYUP_READ_PARENT;
3360                 else
3361                         obj_req->copyup_state = RBD_OBJ_COPYUP_WRITE_OBJECT;
3362                 return false;
3363         case RBD_OBJ_COPYUP_READ_PARENT:
3364                 if (*result)
3365                         return true;
3366 
3367                 if (is_zero_bvecs(obj_req->copyup_bvecs,
3368                                   rbd_obj_img_extents_bytes(obj_req))) {
3369                         dout("%s %p detected zeros\n", __func__, obj_req);
3370                         obj_req->flags |= RBD_OBJ_FLAG_COPYUP_ZEROS;
3371                 }
3372 
3373                 rbd_obj_copyup_object_maps(obj_req);
3374                 if (!obj_req->pending.num_pending) {
3375                         *result = obj_req->pending.result;
3376                         obj_req->copyup_state = RBD_OBJ_COPYUP_OBJECT_MAPS;
3377                         goto again;
3378                 }
3379                 obj_req->copyup_state = __RBD_OBJ_COPYUP_OBJECT_MAPS;
3380                 return false;
3381         case __RBD_OBJ_COPYUP_OBJECT_MAPS:
3382                 if (!pending_result_dec(&obj_req->pending, result))
3383                         return false;
3384                 /* fall through */
3385         case RBD_OBJ_COPYUP_OBJECT_MAPS:
3386                 if (*result) {
3387                         rbd_warn(rbd_dev, "snap object map update failed: %d",
3388                                  *result);
3389                         return true;
3390                 }
3391 
3392                 rbd_obj_copyup_write_object(obj_req);
3393                 if (!obj_req->pending.num_pending) {
3394                         *result = obj_req->pending.result;
3395                         obj_req->copyup_state = RBD_OBJ_COPYUP_WRITE_OBJECT;
3396                         goto again;
3397                 }
3398                 obj_req->copyup_state = __RBD_OBJ_COPYUP_WRITE_OBJECT;
3399                 return false;
3400         case __RBD_OBJ_COPYUP_WRITE_OBJECT:
3401                 if (!pending_result_dec(&obj_req->pending, result))
3402                         return false;
3403                 /* fall through */
3404         case RBD_OBJ_COPYUP_WRITE_OBJECT:
3405                 return true;
3406         default:
3407                 BUG();
3408         }
3409 }
3410 
3411 /*
3412  * Return:
3413  *   0 - object map update sent
3414  *   1 - object map update isn't needed
3415  *  <0 - error
3416  */
3417 static int rbd_obj_write_post_object_map(struct rbd_obj_request *obj_req)
3418 {
3419         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
3420         u8 current_state = OBJECT_PENDING;
3421 
3422         if (!(rbd_dev->header.features & RBD_FEATURE_OBJECT_MAP))
3423                 return 1;
3424 
3425         if (!(obj_req->flags & RBD_OBJ_FLAG_DELETION))
3426                 return 1;
3427 
3428         return rbd_object_map_update(obj_req, CEPH_NOSNAP, OBJECT_NONEXISTENT,
3429                                      &current_state);
3430 }
3431 
3432 static bool rbd_obj_advance_write(struct rbd_obj_request *obj_req, int *result)
3433 {
3434         struct rbd_device *rbd_dev = obj_req->img_request->rbd_dev;
3435         int ret;
3436 
3437 again:
3438         switch (obj_req->write_state) {
3439         case RBD_OBJ_WRITE_START:
3440                 rbd_assert(!*result);
3441 
3442                 if (rbd_obj_write_is_noop(obj_req))
3443                         return true;
3444 
3445                 ret = rbd_obj_write_pre_object_map(obj_req);
3446                 if (ret < 0) {
3447                         *result = ret;
3448                         return true;
3449                 }
3450                 obj_req->write_state = RBD_OBJ_WRITE_PRE_OBJECT_MAP;
3451                 if (ret > 0)
3452                         goto again;
3453                 return false;
3454         case RBD_OBJ_WRITE_PRE_OBJECT_MAP:
3455                 if (*result) {
3456                         rbd_warn(rbd_dev, "pre object map update failed: %d",
3457                                  *result);
3458                         return true;
3459                 }
3460                 ret = rbd_obj_write_object(obj_req);
3461                 if (ret) {
3462                         *result = ret;
3463                         return true;
3464                 }
3465                 obj_req->write_state = RBD_OBJ_WRITE_OBJECT;
3466                 return false;
3467         case RBD_OBJ_WRITE_OBJECT:
3468                 if (*result == -ENOENT) {
3469                         if (obj_req->flags & RBD_OBJ_FLAG_COPYUP_ENABLED) {
3470                                 *result = 0;
3471                                 obj_req->copyup_state = RBD_OBJ_COPYUP_START;
3472                                 obj_req->write_state = __RBD_OBJ_WRITE_COPYUP;
3473                                 goto again;
3474                         }
3475                         /*
3476                          * On a non-existent object:
3477                          *   delete - -ENOENT, truncate/zero - 0
3478                          */
3479                         if (obj_req->flags & RBD_OBJ_FLAG_DELETION)
3480                                 *result = 0;
3481                 }
3482                 if (*result)
3483                         return true;
3484 
3485                 obj_req->write_state = RBD_OBJ_WRITE_COPYUP;
3486                 goto again;
3487         case __RBD_OBJ_WRITE_COPYUP:
3488                 if (!rbd_obj_advance_copyup(obj_req, result))
3489                         return false;
3490                 /* fall through */
3491         case RBD_OBJ_WRITE_COPYUP:
3492                 if (*result) {
3493                         rbd_warn(rbd_dev, "copyup failed: %d", *result);
3494                         return true;
3495                 }
3496                 ret = rbd_obj_write_post_object_map(obj_req);
3497                 if (ret < 0) {
3498                         *result = ret;
3499                         return true;
3500                 }
3501                 obj_req->write_state = RBD_OBJ_WRITE_POST_OBJECT_MAP;
3502                 if (ret > 0)
3503                         goto again;
3504                 return false;
3505         case RBD_OBJ_WRITE_POST_OBJECT_MAP:
3506                 if (*result)
3507                         rbd_warn(rbd_dev, "post object map update failed: %d",
3508                                  *result);
3509                 return true;
3510         default:
3511                 BUG();
3512         }
3513 }
3514 
3515 /*
3516  * Return true if @obj_req is completed.
3517  */
3518 static bool __rbd_obj_handle_request(struct rbd_obj_request *obj_req,
3519                                      int *result)
3520 {
3521         struct rbd_img_request *img_req = obj_req->img_request;
3522         struct rbd_device *rbd_dev = img_req->rbd_dev;
3523         bool done;
3524 
3525         mutex_lock(&obj_req->state_mutex);
3526         if (!rbd_img_is_write(img_req))
3527                 done = rbd_obj_advance_read(obj_req, result);
3528         else
3529                 done = rbd_obj_advance_write(obj_req, result);
3530         mutex_unlock(&obj_req->state_mutex);
3531 
3532         if (done && *result) {
3533                 rbd_assert(*result < 0);
3534                 rbd_warn(rbd_dev, "%s at objno %llu %llu~%llu result %d",
3535                          obj_op_name(img_req->op_type), obj_req->ex.oe_objno,
3536                          obj_req->ex.oe_off, obj_req->ex.oe_len, *result);
3537         }
3538         return done;
3539 }
3540 
3541 /*
3542  * This is open-coded in rbd_img_handle_request() to avoid parent chain
3543  * recursion.
3544  */
3545 static void rbd_obj_handle_request(struct rbd_obj_request *obj_req, int result)
3546 {
3547         if (__rbd_obj_handle_request(obj_req, &result))
3548                 rbd_img_handle_request(obj_req->img_request, result);
3549 }
3550 
3551 static bool need_exclusive_lock(struct rbd_img_request *img_req)
3552 {
3553         struct rbd_device *rbd_dev = img_req->rbd_dev;
3554 
3555         if (!(rbd_dev->header.features & RBD_FEATURE_EXCLUSIVE_LOCK))
3556                 return false;
3557 
3558         if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
3559                 return false;
3560 
3561         rbd_assert(!test_bit(IMG_REQ_CHILD, &img_req->flags));
3562         if (rbd_dev->opts->lock_on_read ||
3563             (rbd_dev->header.features & RBD_FEATURE_OBJECT_MAP))
3564                 return true;
3565 
3566         return rbd_img_is_write(img_req);
3567 }
3568 
3569 static bool rbd_lock_add_request(struct rbd_img_request *img_req)
3570 {
3571         struct rbd_device *rbd_dev = img_req->rbd_dev;
3572         bool locked;
3573 
3574         lockdep_assert_held(&rbd_dev->lock_rwsem);
3575         locked = rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED;
3576         spin_lock(&rbd_dev->lock_lists_lock);
3577         rbd_assert(list_empty(&img_req->lock_item));
3578         if (!locked)
3579                 list_add_tail(&img_req->lock_item, &rbd_dev->acquiring_list);
3580         else
3581                 list_add_tail(&img_req->lock_item, &rbd_dev->running_list);
3582         spin_unlock(&rbd_dev->lock_lists_lock);
3583         return locked;
3584 }
3585 
3586 static void rbd_lock_del_request(struct rbd_img_request *img_req)
3587 {
3588         struct rbd_device *rbd_dev = img_req->rbd_dev;
3589         bool need_wakeup;
3590 
3591         lockdep_assert_held(&rbd_dev->lock_rwsem);
3592         spin_lock(&rbd_dev->lock_lists_lock);
3593         rbd_assert(!list_empty(&img_req->lock_item));
3594         list_del_init(&img_req->lock_item);
3595         need_wakeup = (rbd_dev->lock_state == RBD_LOCK_STATE_RELEASING &&
3596                        list_empty(&rbd_dev->running_list));
3597         spin_unlock(&rbd_dev->lock_lists_lock);
3598         if (need_wakeup)
3599                 complete(&rbd_dev->releasing_wait);
3600 }
3601 
3602 static int rbd_img_exclusive_lock(struct rbd_img_request *img_req)
3603 {
3604         struct rbd_device *rbd_dev = img_req->rbd_dev;
3605 
3606         if (!need_exclusive_lock(img_req))
3607                 return 1;
3608 
3609         if (rbd_lock_add_request(img_req))
3610                 return 1;
3611 
3612         if (rbd_dev->opts->exclusive) {
3613                 WARN_ON(1); /* lock got released? */
3614                 return -EROFS;
3615         }
3616 
3617         /*
3618          * Note the use of mod_delayed_work() in rbd_acquire_lock()
3619          * and cancel_delayed_work() in wake_lock_waiters().
3620          */
3621         dout("%s rbd_dev %p queueing lock_dwork\n", __func__, rbd_dev);
3622         queue_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork, 0);
3623         return 0;
3624 }
3625 
3626 static void rbd_img_object_requests(struct rbd_img_request *img_req)
3627 {
3628         struct rbd_obj_request *obj_req;
3629 
3630         rbd_assert(!img_req->pending.result && !img_req->pending.num_pending);
3631 
3632         for_each_obj_request(img_req, obj_req) {
3633                 int result = 0;
3634 
3635                 if (__rbd_obj_handle_request(obj_req, &result)) {
3636                         if (result) {
3637                                 img_req->pending.result = result;
3638                                 return;
3639                         }
3640                 } else {
3641                         img_req->pending.num_pending++;
3642                 }
3643         }
3644 }
3645 
3646 static bool rbd_img_advance(struct rbd_img_request *img_req, int *result)
3647 {
3648         struct rbd_device *rbd_dev = img_req->rbd_dev;
3649         int ret;
3650 
3651 again:
3652         switch (img_req->state) {
3653         case RBD_IMG_START:
3654                 rbd_assert(!*result);
3655 
3656                 ret = rbd_img_exclusive_lock(img_req);
3657                 if (ret < 0) {
3658                         *result = ret;
3659                         return true;
3660                 }
3661                 img_req->state = RBD_IMG_EXCLUSIVE_LOCK;
3662                 if (ret > 0)
3663                         goto again;
3664                 return false;
3665         case RBD_IMG_EXCLUSIVE_LOCK:
3666                 if (*result)
3667                         return true;
3668 
3669                 rbd_assert(!need_exclusive_lock(img_req) ||
3670                            __rbd_is_lock_owner(rbd_dev));
3671 
3672                 rbd_img_object_requests(img_req);
3673                 if (!img_req->pending.num_pending) {
3674                         *result = img_req->pending.result;
3675                         img_req->state = RBD_IMG_OBJECT_REQUESTS;
3676                         goto again;
3677                 }
3678                 img_req->state = __RBD_IMG_OBJECT_REQUESTS;
3679                 return false;
3680         case __RBD_IMG_OBJECT_REQUESTS:
3681                 if (!pending_result_dec(&img_req->pending, result))
3682                         return false;
3683                 /* fall through */
3684         case RBD_IMG_OBJECT_REQUESTS:
3685                 return true;
3686         default:
3687                 BUG();
3688         }
3689 }
3690 
3691 /*
3692  * Return true if @img_req is completed.
3693  */
3694 static bool __rbd_img_handle_request(struct rbd_img_request *img_req,
3695                                      int *result)
3696 {
3697         struct rbd_device *rbd_dev = img_req->rbd_dev;
3698         bool done;
3699 
3700         if (need_exclusive_lock(img_req)) {
3701                 down_read(&rbd_dev->lock_rwsem);
3702                 mutex_lock(&img_req->state_mutex);
3703                 done = rbd_img_advance(img_req, result);
3704                 if (done)
3705                         rbd_lock_del_request(img_req);
3706                 mutex_unlock(&img_req->state_mutex);
3707                 up_read(&rbd_dev->lock_rwsem);
3708         } else {
3709                 mutex_lock(&img_req->state_mutex);
3710                 done = rbd_img_advance(img_req, result);
3711                 mutex_unlock(&img_req->state_mutex);
3712         }
3713 
3714         if (done && *result) {
3715                 rbd_assert(*result < 0);
3716                 rbd_warn(rbd_dev, "%s%s result %d",
3717                       test_bit(IMG_REQ_CHILD, &img_req->flags) ? "child " : "",
3718                       obj_op_name(img_req->op_type), *result);
3719         }
3720         return done;
3721 }
3722 
3723 static void rbd_img_handle_request(struct rbd_img_request *img_req, int result)
3724 {
3725 again:
3726         if (!__rbd_img_handle_request(img_req, &result))
3727                 return;
3728 
3729         if (test_bit(IMG_REQ_CHILD, &img_req->flags)) {
3730                 struct rbd_obj_request *obj_req = img_req->obj_request;
3731 
3732                 rbd_img_request_put(img_req);
3733                 if (__rbd_obj_handle_request(obj_req, &result)) {
3734                         img_req = obj_req->img_request;
3735                         goto again;
3736                 }
3737         } else {
3738                 struct request *rq = img_req->rq;
3739 
3740                 rbd_img_request_put(img_req);
3741                 blk_mq_end_request(rq, errno_to_blk_status(result));
3742         }
3743 }
3744 
3745 static const struct rbd_client_id rbd_empty_cid;
3746 
3747 static bool rbd_cid_equal(const struct rbd_client_id *lhs,
3748                           const struct rbd_client_id *rhs)
3749 {
3750         return lhs->gid == rhs->gid && lhs->handle == rhs->handle;
3751 }
3752 
3753 static struct rbd_client_id rbd_get_cid(struct rbd_device *rbd_dev)
3754 {
3755         struct rbd_client_id cid;
3756 
3757         mutex_lock(&rbd_dev->watch_mutex);
3758         cid.gid = ceph_client_gid(rbd_dev->rbd_client->client);
3759         cid.handle = rbd_dev->watch_cookie;
3760         mutex_unlock(&rbd_dev->watch_mutex);
3761         return cid;
3762 }
3763 
3764 /*
3765  * lock_rwsem must be held for write
3766  */
3767 static void rbd_set_owner_cid(struct rbd_device *rbd_dev,
3768                               const struct rbd_client_id *cid)
3769 {
3770         dout("%s rbd_dev %p %llu-%llu -> %llu-%llu\n", __func__, rbd_dev,
3771              rbd_dev->owner_cid.gid, rbd_dev->owner_cid.handle,
3772              cid->gid, cid->handle);
3773         rbd_dev->owner_cid = *cid; /* struct */
3774 }
3775 
3776 static void format_lock_cookie(struct rbd_device *rbd_dev, char *buf)
3777 {
3778         mutex_lock(&rbd_dev->watch_mutex);
3779         sprintf(buf, "%s %llu", RBD_LOCK_COOKIE_PREFIX, rbd_dev->watch_cookie);
3780         mutex_unlock(&rbd_dev->watch_mutex);
3781 }
3782 
3783 static void __rbd_lock(struct rbd_device *rbd_dev, const char *cookie)
3784 {
3785         struct rbd_client_id cid = rbd_get_cid(rbd_dev);
3786 
3787         rbd_dev->lock_state = RBD_LOCK_STATE_LOCKED;
3788         strcpy(rbd_dev->lock_cookie, cookie);
3789         rbd_set_owner_cid(rbd_dev, &cid);
3790         queue_work(rbd_dev->task_wq, &rbd_dev->acquired_lock_work);
3791 }
3792 
3793 /*
3794  * lock_rwsem must be held for write
3795  */
3796 static int rbd_lock(struct rbd_device *rbd_dev)
3797 {
3798         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3799         char cookie[32];
3800         int ret;
3801 
3802         WARN_ON(__rbd_is_lock_owner(rbd_dev) ||
3803                 rbd_dev->lock_cookie[0] != '\0');
3804 
3805         format_lock_cookie(rbd_dev, cookie);
3806         ret = ceph_cls_lock(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
3807                             RBD_LOCK_NAME, CEPH_CLS_LOCK_EXCLUSIVE, cookie,
3808                             RBD_LOCK_TAG, "", 0);
3809         if (ret)
3810                 return ret;
3811 
3812         __rbd_lock(rbd_dev, cookie);
3813         return 0;
3814 }
3815 
3816 /*
3817  * lock_rwsem must be held for write
3818  */
3819 static void rbd_unlock(struct rbd_device *rbd_dev)
3820 {
3821         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3822         int ret;
3823 
3824         WARN_ON(!__rbd_is_lock_owner(rbd_dev) ||
3825                 rbd_dev->lock_cookie[0] == '\0');
3826 
3827         ret = ceph_cls_unlock(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
3828                               RBD_LOCK_NAME, rbd_dev->lock_cookie);
3829         if (ret && ret != -ENOENT)
3830                 rbd_warn(rbd_dev, "failed to unlock header: %d", ret);
3831 
3832         /* treat errors as the image is unlocked */
3833         rbd_dev->lock_state = RBD_LOCK_STATE_UNLOCKED;
3834         rbd_dev->lock_cookie[0] = '\0';
3835         rbd_set_owner_cid(rbd_dev, &rbd_empty_cid);
3836         queue_work(rbd_dev->task_wq, &rbd_dev->released_lock_work);
3837 }
3838 
3839 static int __rbd_notify_op_lock(struct rbd_device *rbd_dev,
3840                                 enum rbd_notify_op notify_op,
3841                                 struct page ***preply_pages,
3842                                 size_t *preply_len)
3843 {
3844         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3845         struct rbd_client_id cid = rbd_get_cid(rbd_dev);
3846         char buf[4 + 8 + 8 + CEPH_ENCODING_START_BLK_LEN];
3847         int buf_size = sizeof(buf);
3848         void *p = buf;
3849 
3850         dout("%s rbd_dev %p notify_op %d\n", __func__, rbd_dev, notify_op);
3851 
3852         /* encode *LockPayload NotifyMessage (op + ClientId) */
3853         ceph_start_encoding(&p, 2, 1, buf_size - CEPH_ENCODING_START_BLK_LEN);
3854         ceph_encode_32(&p, notify_op);
3855         ceph_encode_64(&p, cid.gid);
3856         ceph_encode_64(&p, cid.handle);
3857 
3858         return ceph_osdc_notify(osdc, &rbd_dev->header_oid,
3859                                 &rbd_dev->header_oloc, buf, buf_size,
3860                                 RBD_NOTIFY_TIMEOUT, preply_pages, preply_len);
3861 }
3862 
3863 static void rbd_notify_op_lock(struct rbd_device *rbd_dev,
3864                                enum rbd_notify_op notify_op)
3865 {
3866         struct page **reply_pages;
3867         size_t reply_len;
3868 
3869         __rbd_notify_op_lock(rbd_dev, notify_op, &reply_pages, &reply_len);
3870         ceph_release_page_vector(reply_pages, calc_pages_for(0, reply_len));
3871 }
3872 
3873 static void rbd_notify_acquired_lock(struct work_struct *work)
3874 {
3875         struct rbd_device *rbd_dev = container_of(work, struct rbd_device,
3876                                                   acquired_lock_work);
3877 
3878         rbd_notify_op_lock(rbd_dev, RBD_NOTIFY_OP_ACQUIRED_LOCK);
3879 }
3880 
3881 static void rbd_notify_released_lock(struct work_struct *work)
3882 {
3883         struct rbd_device *rbd_dev = container_of(work, struct rbd_device,
3884                                                   released_lock_work);
3885 
3886         rbd_notify_op_lock(rbd_dev, RBD_NOTIFY_OP_RELEASED_LOCK);
3887 }
3888 
3889 static int rbd_request_lock(struct rbd_device *rbd_dev)
3890 {
3891         struct page **reply_pages;
3892         size_t reply_len;
3893         bool lock_owner_responded = false;
3894         int ret;
3895 
3896         dout("%s rbd_dev %p\n", __func__, rbd_dev);
3897 
3898         ret = __rbd_notify_op_lock(rbd_dev, RBD_NOTIFY_OP_REQUEST_LOCK,
3899                                    &reply_pages, &reply_len);
3900         if (ret && ret != -ETIMEDOUT) {
3901                 rbd_warn(rbd_dev, "failed to request lock: %d", ret);
3902                 goto out;
3903         }
3904 
3905         if (reply_len > 0 && reply_len <= PAGE_SIZE) {
3906                 void *p = page_address(reply_pages[0]);
3907                 void *const end = p + reply_len;
3908                 u32 n;
3909 
3910                 ceph_decode_32_safe(&p, end, n, e_inval); /* num_acks */
3911                 while (n--) {
3912                         u8 struct_v;
3913                         u32 len;
3914 
3915                         ceph_decode_need(&p, end, 8 + 8, e_inval);
3916                         p += 8 + 8; /* skip gid and cookie */
3917 
3918                         ceph_decode_32_safe(&p, end, len, e_inval);
3919                         if (!len)
3920                                 continue;
3921 
3922                         if (lock_owner_responded) {
3923                                 rbd_warn(rbd_dev,
3924                                          "duplicate lock owners detected");
3925                                 ret = -EIO;
3926                                 goto out;
3927                         }
3928 
3929                         lock_owner_responded = true;
3930                         ret = ceph_start_decoding(&p, end, 1, "ResponseMessage",
3931                                                   &struct_v, &len);
3932                         if (ret) {
3933                                 rbd_warn(rbd_dev,
3934                                          "failed to decode ResponseMessage: %d",
3935                                          ret);
3936                                 goto e_inval;
3937                         }
3938 
3939                         ret = ceph_decode_32(&p);
3940                 }
3941         }
3942 
3943         if (!lock_owner_responded) {
3944                 rbd_warn(rbd_dev, "no lock owners detected");
3945                 ret = -ETIMEDOUT;
3946         }
3947 
3948 out:
3949         ceph_release_page_vector(reply_pages, calc_pages_for(0, reply_len));
3950         return ret;
3951 
3952 e_inval:
3953         ret = -EINVAL;
3954         goto out;
3955 }
3956 
3957 /*
3958  * Either image request state machine(s) or rbd_add_acquire_lock()
3959  * (i.e. "rbd map").
3960  */
3961 static void wake_lock_waiters(struct rbd_device *rbd_dev, int result)
3962 {
3963         struct rbd_img_request *img_req;
3964 
3965         dout("%s rbd_dev %p result %d\n", __func__, rbd_dev, result);
3966         lockdep_assert_held_write(&rbd_dev->lock_rwsem);
3967 
3968         cancel_delayed_work(&rbd_dev->lock_dwork);
3969         if (!completion_done(&rbd_dev->acquire_wait)) {
3970                 rbd_assert(list_empty(&rbd_dev->acquiring_list) &&
3971                            list_empty(&rbd_dev->running_list));
3972                 rbd_dev->acquire_err = result;
3973                 complete_all(&rbd_dev->acquire_wait);
3974                 return;
3975         }
3976 
3977         list_for_each_entry(img_req, &rbd_dev->acquiring_list, lock_item) {
3978                 mutex_lock(&img_req->state_mutex);
3979                 rbd_assert(img_req->state == RBD_IMG_EXCLUSIVE_LOCK);
3980                 rbd_img_schedule(img_req, result);
3981                 mutex_unlock(&img_req->state_mutex);
3982         }
3983 
3984         list_splice_tail_init(&rbd_dev->acquiring_list, &rbd_dev->running_list);
3985 }
3986 
3987 static int get_lock_owner_info(struct rbd_device *rbd_dev,
3988                                struct ceph_locker **lockers, u32 *num_lockers)
3989 {
3990         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
3991         u8 lock_type;
3992         char *lock_tag;
3993         int ret;
3994 
3995         dout("%s rbd_dev %p\n", __func__, rbd_dev);
3996 
3997         ret = ceph_cls_lock_info(osdc, &rbd_dev->header_oid,
3998                                  &rbd_dev->header_oloc, RBD_LOCK_NAME,
3999                                  &lock_type, &lock_tag, lockers, num_lockers);
4000         if (ret)
4001                 return ret;
4002 
4003         if (*num_lockers == 0) {
4004                 dout("%s rbd_dev %p no lockers detected\n", __func__, rbd_dev);
4005                 goto out;
4006         }
4007 
4008         if (strcmp(lock_tag, RBD_LOCK_TAG)) {
4009                 rbd_warn(rbd_dev, "locked by external mechanism, tag %s",
4010                          lock_tag);
4011                 ret = -EBUSY;
4012                 goto out;
4013         }
4014 
4015         if (lock_type == CEPH_CLS_LOCK_SHARED) {
4016                 rbd_warn(rbd_dev, "shared lock type detected");
4017                 ret = -EBUSY;
4018                 goto out;
4019         }
4020 
4021         if (strncmp((*lockers)[0].id.cookie, RBD_LOCK_COOKIE_PREFIX,
4022                     strlen(RBD_LOCK_COOKIE_PREFIX))) {
4023                 rbd_warn(rbd_dev, "locked by external mechanism, cookie %s",
4024                          (*lockers)[0].id.cookie);
4025                 ret = -EBUSY;
4026                 goto out;
4027         }
4028 
4029 out:
4030         kfree(lock_tag);
4031         return ret;
4032 }
4033 
4034 static int find_watcher(struct rbd_device *rbd_dev,
4035                         const struct ceph_locker *locker)
4036 {
4037         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
4038         struct ceph_watch_item *watchers;
4039         u32 num_watchers;
4040         u64 cookie;
4041         int i;
4042         int ret;
4043 
4044         ret = ceph_osdc_list_watchers(osdc, &rbd_dev->header_oid,
4045                                       &rbd_dev->header_oloc, &watchers,
4046                                       &num_watchers);
4047         if (ret)
4048                 return ret;
4049 
4050         sscanf(locker->id.cookie, RBD_LOCK_COOKIE_PREFIX " %llu", &cookie);
4051         for (i = 0; i < num_watchers; i++) {
4052                 if (!memcmp(&watchers[i].addr, &locker->info.addr,
4053                             sizeof(locker->info.addr)) &&
4054                     watchers[i].cookie == cookie) {
4055                         struct rbd_client_id cid = {
4056                                 .gid = le64_to_cpu(watchers[i].name.num),
4057                                 .handle = cookie,
4058                         };
4059 
4060                         dout("%s rbd_dev %p found cid %llu-%llu\n", __func__,
4061                              rbd_dev, cid.gid, cid.handle);
4062                         rbd_set_owner_cid(rbd_dev, &cid);
4063                         ret = 1;
4064                         goto out;
4065                 }
4066         }
4067 
4068         dout("%s rbd_dev %p no watchers\n", __func__, rbd_dev);
4069         ret = 0;
4070 out:
4071         kfree(watchers);
4072         return ret;
4073 }
4074 
4075 /*
4076  * lock_rwsem must be held for write
4077  */
4078 static int rbd_try_lock(struct rbd_device *rbd_dev)
4079 {
4080         struct ceph_client *client = rbd_dev->rbd_client->client;
4081         struct ceph_locker *lockers;
4082         u32 num_lockers;
4083         int ret;
4084 
4085         for (;;) {
4086                 ret = rbd_lock(rbd_dev);
4087                 if (ret != -EBUSY)
4088                         return ret;
4089 
4090                 /* determine if the current lock holder is still alive */
4091                 ret = get_lock_owner_info(rbd_dev, &lockers, &num_lockers);
4092                 if (ret)
4093                         return ret;
4094 
4095                 if (num_lockers == 0)
4096                         goto again;
4097 
4098                 ret = find_watcher(rbd_dev, lockers);
4099                 if (ret)
4100                         goto out; /* request lock or error */
4101 
4102                 rbd_warn(rbd_dev, "breaking header lock owned by %s%llu",
4103                          ENTITY_NAME(lockers[0].id.name));
4104 
4105                 ret = ceph_monc_blacklist_add(&client->monc,
4106                                               &lockers[0].info.addr);
4107                 if (ret) {
4108                         rbd_warn(rbd_dev, "blacklist of %s%llu failed: %d",
4109                                  ENTITY_NAME(lockers[0].id.name), ret);
4110                         goto out;
4111                 }
4112 
4113                 ret = ceph_cls_break_lock(&client->osdc, &rbd_dev->header_oid,
4114                                           &rbd_dev->header_oloc, RBD_LOCK_NAME,
4115                                           lockers[0].id.cookie,
4116                                           &lockers[0].id.name);
4117                 if (ret && ret != -ENOENT)
4118                         goto out;
4119 
4120 again:
4121                 ceph_free_lockers(lockers, num_lockers);
4122         }
4123 
4124 out:
4125         ceph_free_lockers(lockers, num_lockers);
4126         return ret;
4127 }
4128 
4129 static int rbd_post_acquire_action(struct rbd_device *rbd_dev)
4130 {
4131         int ret;
4132 
4133         if (rbd_dev->header.features & RBD_FEATURE_OBJECT_MAP) {
4134                 ret = rbd_object_map_open(rbd_dev);
4135                 if (ret)
4136                         return ret;
4137         }
4138 
4139         return 0;
4140 }
4141 
4142 /*
4143  * Return:
4144  *   0 - lock acquired
4145  *   1 - caller should call rbd_request_lock()
4146  *  <0 - error
4147  */
4148 static int rbd_try_acquire_lock(struct rbd_device *rbd_dev)
4149 {
4150         int ret;
4151 
4152         down_read(&rbd_dev->lock_rwsem);
4153         dout("%s rbd_dev %p read lock_state %d\n", __func__, rbd_dev,
4154              rbd_dev->lock_state);
4155         if (__rbd_is_lock_owner(rbd_dev)) {
4156                 up_read(&rbd_dev->lock_rwsem);
4157                 return 0;
4158         }
4159 
4160         up_read(&rbd_dev->lock_rwsem);
4161         down_write(&rbd_dev->lock_rwsem);
4162         dout("%s rbd_dev %p write lock_state %d\n", __func__, rbd_dev,
4163              rbd_dev->lock_state);
4164         if (__rbd_is_lock_owner(rbd_dev)) {
4165                 up_write(&rbd_dev->lock_rwsem);
4166                 return 0;
4167         }
4168 
4169         ret = rbd_try_lock(rbd_dev);
4170         if (ret < 0) {
4171                 rbd_warn(rbd_dev, "failed to lock header: %d", ret);
4172                 if (ret == -EBLACKLISTED)
4173                         goto out;
4174 
4175                 ret = 1; /* request lock anyway */
4176         }
4177         if (ret > 0) {
4178                 up_write(&rbd_dev->lock_rwsem);
4179                 return ret;
4180         }
4181 
4182         rbd_assert(rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED);
4183         rbd_assert(list_empty(&rbd_dev->running_list));
4184 
4185         ret = rbd_post_acquire_action(rbd_dev);
4186         if (ret) {
4187                 rbd_warn(rbd_dev, "post-acquire action failed: %d", ret);
4188                 /*
4189                  * Can't stay in RBD_LOCK_STATE_LOCKED because
4190                  * rbd_lock_add_request() would let the request through,
4191                  * assuming that e.g. object map is locked and loaded.
4192                  */
4193                 rbd_unlock(rbd_dev);
4194         }
4195 
4196 out:
4197         wake_lock_waiters(rbd_dev, ret);
4198         up_write(&rbd_dev->lock_rwsem);
4199         return ret;
4200 }
4201 
4202 static void rbd_acquire_lock(struct work_struct *work)
4203 {
4204         struct rbd_device *rbd_dev = container_of(to_delayed_work(work),
4205                                             struct rbd_device, lock_dwork);
4206         int ret;
4207 
4208         dout("%s rbd_dev %p\n", __func__, rbd_dev);
4209 again:
4210         ret = rbd_try_acquire_lock(rbd_dev);
4211         if (ret <= 0) {
4212                 dout("%s rbd_dev %p ret %d - done\n", __func__, rbd_dev, ret);
4213                 return;
4214         }
4215 
4216         ret = rbd_request_lock(rbd_dev);
4217         if (ret == -ETIMEDOUT) {
4218                 goto again; /* treat this as a dead client */
4219         } else if (ret == -EROFS) {
4220                 rbd_warn(rbd_dev, "peer will not release lock");
4221                 down_write(&rbd_dev->lock_rwsem);
4222                 wake_lock_waiters(rbd_dev, ret);
4223                 up_write(&rbd_dev->lock_rwsem);
4224         } else if (ret < 0) {
4225                 rbd_warn(rbd_dev, "error requesting lock: %d", ret);
4226                 mod_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork,
4227                                  RBD_RETRY_DELAY);
4228         } else {
4229                 /*
4230                  * lock owner acked, but resend if we don't see them
4231                  * release the lock
4232                  */
4233                 dout("%s rbd_dev %p requeueing lock_dwork\n", __func__,
4234                      rbd_dev);
4235                 mod_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork,
4236                     msecs_to_jiffies(2 * RBD_NOTIFY_TIMEOUT * MSEC_PER_SEC));
4237         }
4238 }
4239 
4240 static bool rbd_quiesce_lock(struct rbd_device *rbd_dev)
4241 {
4242         bool need_wait;
4243 
4244         dout("%s rbd_dev %p\n", __func__, rbd_dev);
4245         lockdep_assert_held_write(&rbd_dev->lock_rwsem);
4246 
4247         if (rbd_dev->lock_state != RBD_LOCK_STATE_LOCKED)
4248                 return false;
4249 
4250         /*
4251          * Ensure that all in-flight IO is flushed.
4252          */
4253         rbd_dev->lock_state = RBD_LOCK_STATE_RELEASING;
4254         rbd_assert(!completion_done(&rbd_dev->releasing_wait));
4255         need_wait = !list_empty(&rbd_dev->running_list);
4256         downgrade_write(&rbd_dev->lock_rwsem);
4257         if (need_wait)
4258                 wait_for_completion(&rbd_dev->releasing_wait);
4259         up_read(&rbd_dev->lock_rwsem);
4260 
4261         down_write(&rbd_dev->lock_rwsem);
4262         if (rbd_dev->lock_state != RBD_LOCK_STATE_RELEASING)
4263                 return false;
4264 
4265         rbd_assert(list_empty(&rbd_dev->running_list));
4266         return true;
4267 }
4268 
4269 static void rbd_pre_release_action(struct rbd_device *rbd_dev)
4270 {
4271         if (rbd_dev->header.features & RBD_FEATURE_OBJECT_MAP)
4272                 rbd_object_map_close(rbd_dev);
4273 }
4274 
4275 static void __rbd_release_lock(struct rbd_device *rbd_dev)
4276 {
4277         rbd_assert(list_empty(&rbd_dev->running_list));
4278 
4279         rbd_pre_release_action(rbd_dev);
4280         rbd_unlock(rbd_dev);
4281 }
4282 
4283 /*
4284  * lock_rwsem must be held for write
4285  */
4286 static void rbd_release_lock(struct rbd_device *rbd_dev)
4287 {
4288         if (!rbd_quiesce_lock(rbd_dev))
4289                 return;
4290 
4291         __rbd_release_lock(rbd_dev);
4292 
4293         /*
4294          * Give others a chance to grab the lock - we would re-acquire
4295          * almost immediately if we got new IO while draining the running
4296          * list otherwise.  We need to ack our own notifications, so this
4297          * lock_dwork will be requeued from rbd_handle_released_lock() by
4298          * way of maybe_kick_acquire().
4299          */
4300         cancel_delayed_work(&rbd_dev->lock_dwork);
4301 }
4302 
4303 static void rbd_release_lock_work(struct work_struct *work)
4304 {
4305         struct rbd_device *rbd_dev = container_of(work, struct rbd_device,
4306                                                   unlock_work);
4307 
4308         down_write(&rbd_dev->lock_rwsem);
4309         rbd_release_lock(rbd_dev);
4310         up_write(&rbd_dev->lock_rwsem);
4311 }
4312 
4313 static void maybe_kick_acquire(struct rbd_device *rbd_dev)
4314 {
4315         bool have_requests;
4316 
4317         dout("%s rbd_dev %p\n", __func__, rbd_dev);
4318         if (__rbd_is_lock_owner(rbd_dev))
4319                 return;
4320 
4321         spin_lock(&rbd_dev->lock_lists_lock);
4322         have_requests = !list_empty(&rbd_dev->acquiring_list);
4323         spin_unlock(&rbd_dev->lock_lists_lock);
4324         if (have_requests || delayed_work_pending(&rbd_dev->lock_dwork)) {
4325                 dout("%s rbd_dev %p kicking lock_dwork\n", __func__, rbd_dev);
4326                 mod_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork, 0);
4327         }
4328 }
4329 
4330 static void rbd_handle_acquired_lock(struct rbd_device *rbd_dev, u8 struct_v,
4331                                      void **p)
4332 {
4333         struct rbd_client_id cid = { 0 };
4334 
4335         if (struct_v >= 2) {
4336                 cid.gid = ceph_decode_64(p);
4337                 cid.handle = ceph_decode_64(p);
4338         }
4339 
4340         dout("%s rbd_dev %p cid %llu-%llu\n", __func__, rbd_dev, cid.gid,
4341              cid.handle);
4342         if (!rbd_cid_equal(&cid, &rbd_empty_cid)) {
4343                 down_write(&rbd_dev->lock_rwsem);
4344                 if (rbd_cid_equal(&cid, &rbd_dev->owner_cid)) {
4345                         /*
4346                          * we already know that the remote client is
4347                          * the owner
4348                          */
4349                         up_write(&rbd_dev->lock_rwsem);
4350                         return;
4351                 }
4352 
4353                 rbd_set_owner_cid(rbd_dev, &cid);
4354                 downgrade_write(&rbd_dev->lock_rwsem);
4355         } else {
4356                 down_read(&rbd_dev->lock_rwsem);
4357         }
4358 
4359         maybe_kick_acquire(rbd_dev);
4360         up_read(&rbd_dev->lock_rwsem);
4361 }
4362 
4363 static void rbd_handle_released_lock(struct rbd_device *rbd_dev, u8 struct_v,
4364                                      void **p)
4365 {
4366         struct rbd_client_id cid = { 0 };
4367 
4368         if (struct_v >= 2) {
4369                 cid.gid = ceph_decode_64(p);
4370                 cid.handle = ceph_decode_64(p);
4371         }
4372 
4373         dout("%s rbd_dev %p cid %llu-%llu\n", __func__, rbd_dev, cid.gid,
4374              cid.handle);
4375         if (!rbd_cid_equal(&cid, &rbd_empty_cid)) {
4376                 down_write(&rbd_dev->lock_rwsem);
4377                 if (!rbd_cid_equal(&cid, &rbd_dev->owner_cid)) {
4378                         dout("%s rbd_dev %p unexpected owner, cid %llu-%llu != owner_cid %llu-%llu\n",
4379                              __func__, rbd_dev, cid.gid, cid.handle,
4380                              rbd_dev->owner_cid.gid, rbd_dev->owner_cid.handle);
4381                         up_write(&rbd_dev->lock_rwsem);
4382                         return;
4383                 }
4384 
4385                 rbd_set_owner_cid(rbd_dev, &rbd_empty_cid);
4386                 downgrade_write(&rbd_dev->lock_rwsem);
4387         } else {
4388                 down_read(&rbd_dev->lock_rwsem);
4389         }
4390 
4391         maybe_kick_acquire(rbd_dev);
4392         up_read(&rbd_dev->lock_rwsem);
4393 }
4394 
4395 /*
4396  * Returns result for ResponseMessage to be encoded (<= 0), or 1 if no
4397  * ResponseMessage is needed.
4398  */
4399 static int rbd_handle_request_lock(struct rbd_device *rbd_dev, u8 struct_v,
4400                                    void **p)
4401 {
4402         struct rbd_client_id my_cid = rbd_get_cid(rbd_dev);
4403         struct rbd_client_id cid = { 0 };
4404         int result = 1;
4405 
4406         if (struct_v >= 2) {
4407                 cid.gid = ceph_decode_64(p);
4408                 cid.handle = ceph_decode_64(p);
4409         }
4410 
4411         dout("%s rbd_dev %p cid %llu-%llu\n", __func__, rbd_dev, cid.gid,
4412              cid.handle);
4413         if (rbd_cid_equal(&cid, &my_cid))
4414                 return result;
4415 
4416         down_read(&rbd_dev->lock_rwsem);
4417         if (__rbd_is_lock_owner(rbd_dev)) {
4418                 if (rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED &&
4419                     rbd_cid_equal(&rbd_dev->owner_cid, &rbd_empty_cid))
4420                         goto out_unlock;
4421 
4422                 /*
4423                  * encode ResponseMessage(0) so the peer can detect
4424                  * a missing owner
4425                  */
4426                 result = 0;
4427 
4428                 if (rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED) {
4429                         if (!rbd_dev->opts->exclusive) {
4430                                 dout("%s rbd_dev %p queueing unlock_work\n",
4431                                      __func__, rbd_dev);
4432                                 queue_work(rbd_dev->task_wq,
4433                                            &rbd_dev->unlock_work);
4434                         } else {
4435                                 /* refuse to release the lock */
4436                                 result = -EROFS;
4437                         }
4438                 }
4439         }
4440 
4441 out_unlock:
4442         up_read(&rbd_dev->lock_rwsem);
4443         return result;
4444 }
4445 
4446 static void __rbd_acknowledge_notify(struct rbd_device *rbd_dev,
4447                                      u64 notify_id, u64 cookie, s32 *result)
4448 {
4449         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
4450         char buf[4 + CEPH_ENCODING_START_BLK_LEN];
4451         int buf_size = sizeof(buf);
4452         int ret;
4453 
4454         if (result) {
4455                 void *p = buf;
4456 
4457                 /* encode ResponseMessage */
4458                 ceph_start_encoding(&p, 1, 1,
4459                                     buf_size - CEPH_ENCODING_START_BLK_LEN);
4460                 ceph_encode_32(&p, *result);
4461         } else {
4462                 buf_size = 0;
4463         }
4464 
4465         ret = ceph_osdc_notify_ack(osdc, &rbd_dev->header_oid,
4466                                    &rbd_dev->header_oloc, notify_id, cookie,
4467                                    buf, buf_size);
4468         if (ret)
4469                 rbd_warn(rbd_dev, "acknowledge_notify failed: %d", ret);
4470 }
4471 
4472 static void rbd_acknowledge_notify(struct rbd_device *rbd_dev, u64 notify_id,
4473                                    u64 cookie)
4474 {
4475         dout("%s rbd_dev %p\n", __func__, rbd_dev);
4476         __rbd_acknowledge_notify(rbd_dev, notify_id, cookie, NULL);
4477 }
4478 
4479 static void rbd_acknowledge_notify_result(struct rbd_device *rbd_dev,
4480                                           u64 notify_id, u64 cookie, s32 result)
4481 {
4482         dout("%s rbd_dev %p result %d\n", __func__, rbd_dev, result);
4483         __rbd_acknowledge_notify(rbd_dev, notify_id, cookie, &result);
4484 }
4485 
4486 static void rbd_watch_cb(void *arg, u64 notify_id, u64 cookie,
4487                          u64 notifier_id, void *data, size_t data_len)
4488 {
4489         struct rbd_device *rbd_dev = arg;
4490         void *p = data;
4491         void *const end = p + data_len;
4492         u8 struct_v = 0;
4493         u32 len;
4494         u32 notify_op;
4495         int ret;
4496 
4497         dout("%s rbd_dev %p cookie %llu notify_id %llu data_len %zu\n",
4498              __func__, rbd_dev, cookie, notify_id, data_len);
4499         if (data_len) {
4500                 ret = ceph_start_decoding(&p, end, 1, "NotifyMessage",
4501                                           &struct_v, &len);
4502                 if (ret) {
4503                         rbd_warn(rbd_dev, "failed to decode NotifyMessage: %d",
4504                                  ret);
4505                         return;
4506                 }
4507 
4508                 notify_op = ceph_decode_32(&p);
4509         } else {
4510                 /* legacy notification for header updates */
4511                 notify_op = RBD_NOTIFY_OP_HEADER_UPDATE;
4512                 len = 0;
4513         }
4514 
4515         dout("%s rbd_dev %p notify_op %u\n", __func__, rbd_dev, notify_op);
4516         switch (notify_op) {
4517         case RBD_NOTIFY_OP_ACQUIRED_LOCK:
4518                 rbd_handle_acquired_lock(rbd_dev, struct_v, &p);
4519                 rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
4520                 break;
4521         case RBD_NOTIFY_OP_RELEASED_LOCK:
4522                 rbd_handle_released_lock(rbd_dev, struct_v, &p);
4523                 rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
4524                 break;
4525         case RBD_NOTIFY_OP_REQUEST_LOCK:
4526                 ret = rbd_handle_request_lock(rbd_dev, struct_v, &p);
4527                 if (ret <= 0)
4528                         rbd_acknowledge_notify_result(rbd_dev, notify_id,
4529                                                       cookie, ret);
4530                 else
4531                         rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
4532                 break;
4533         case RBD_NOTIFY_OP_HEADER_UPDATE:
4534                 ret = rbd_dev_refresh(rbd_dev);
4535                 if (ret)
4536                         rbd_warn(rbd_dev, "refresh failed: %d", ret);
4537 
4538                 rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
4539                 break;
4540         default:
4541                 if (rbd_is_lock_owner(rbd_dev))
4542                         rbd_acknowledge_notify_result(rbd_dev, notify_id,
4543                                                       cookie, -EOPNOTSUPP);
4544                 else
4545                         rbd_acknowledge_notify(rbd_dev, notify_id, cookie);
4546                 break;
4547         }
4548 }
4549 
4550 static void __rbd_unregister_watch(struct rbd_device *rbd_dev);
4551 
4552 static void rbd_watch_errcb(void *arg, u64 cookie, int err)
4553 {
4554         struct rbd_device *rbd_dev = arg;
4555 
4556         rbd_warn(rbd_dev, "encountered watch error: %d", err);
4557 
4558         down_write(&rbd_dev->lock_rwsem);
4559         rbd_set_owner_cid(rbd_dev, &rbd_empty_cid);
4560         up_write(&rbd_dev->lock_rwsem);
4561 
4562         mutex_lock(&rbd_dev->watch_mutex);
4563         if (rbd_dev->watch_state == RBD_WATCH_STATE_REGISTERED) {
4564                 __rbd_unregister_watch(rbd_dev);
4565                 rbd_dev->watch_state = RBD_WATCH_STATE_ERROR;
4566 
4567                 queue_delayed_work(rbd_dev->task_wq, &rbd_dev->watch_dwork, 0);
4568         }
4569         mutex_unlock(&rbd_dev->watch_mutex);
4570 }
4571 
4572 /*
4573  * watch_mutex must be locked
4574  */
4575 static int __rbd_register_watch(struct rbd_device *rbd_dev)
4576 {
4577         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
4578         struct ceph_osd_linger_request *handle;
4579 
4580         rbd_assert(!rbd_dev->watch_handle);
4581         dout("%s rbd_dev %p\n", __func__, rbd_dev);
4582 
4583         handle = ceph_osdc_watch(osdc, &rbd_dev->header_oid,
4584                                  &rbd_dev->header_oloc, rbd_watch_cb,
4585                                  rbd_watch_errcb, rbd_dev);
4586         if (IS_ERR(handle))
4587                 return PTR_ERR(handle);
4588 
4589         rbd_dev->watch_handle = handle;
4590         return 0;
4591 }
4592 
4593 /*
4594  * watch_mutex must be locked
4595  */
4596 static void __rbd_unregister_watch(struct rbd_device *rbd_dev)
4597 {
4598         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
4599         int ret;
4600 
4601         rbd_assert(rbd_dev->watch_handle);
4602         dout("%s rbd_dev %p\n", __func__, rbd_dev);
4603 
4604         ret = ceph_osdc_unwatch(osdc, rbd_dev->watch_handle);
4605         if (ret)
4606                 rbd_warn(rbd_dev, "failed to unwatch: %d", ret);
4607 
4608         rbd_dev->watch_handle = NULL;
4609 }
4610 
4611 static int rbd_register_watch(struct rbd_device *rbd_dev)
4612 {
4613         int ret;
4614 
4615         mutex_lock(&rbd_dev->watch_mutex);
4616         rbd_assert(rbd_dev->watch_state == RBD_WATCH_STATE_UNREGISTERED);
4617         ret = __rbd_register_watch(rbd_dev);
4618         if (ret)
4619                 goto out;
4620 
4621         rbd_dev->watch_state = RBD_WATCH_STATE_REGISTERED;
4622         rbd_dev->watch_cookie = rbd_dev->watch_handle->linger_id;
4623 
4624 out:
4625         mutex_unlock(&rbd_dev->watch_mutex);
4626         return ret;
4627 }
4628 
4629 static void cancel_tasks_sync(struct rbd_device *rbd_dev)
4630 {
4631         dout("%s rbd_dev %p\n", __func__, rbd_dev);
4632 
4633         cancel_work_sync(&rbd_dev->acquired_lock_work);
4634         cancel_work_sync(&rbd_dev->released_lock_work);
4635         cancel_delayed_work_sync(&rbd_dev->lock_dwork);
4636         cancel_work_sync(&rbd_dev->unlock_work);
4637 }
4638 
4639 /*
4640  * header_rwsem must not be held to avoid a deadlock with
4641  * rbd_dev_refresh() when flushing notifies.
4642  */
4643 static void rbd_unregister_watch(struct rbd_device *rbd_dev)
4644 {
4645         cancel_tasks_sync(rbd_dev);
4646 
4647         mutex_lock(&rbd_dev->watch_mutex);
4648         if (rbd_dev->watch_state == RBD_WATCH_STATE_REGISTERED)
4649                 __rbd_unregister_watch(rbd_dev);
4650         rbd_dev->watch_state = RBD_WATCH_STATE_UNREGISTERED;
4651         mutex_unlock(&rbd_dev->watch_mutex);
4652 
4653         cancel_delayed_work_sync(&rbd_dev->watch_dwork);
4654         ceph_osdc_flush_notifies(&rbd_dev->rbd_client->client->osdc);
4655 }
4656 
4657 /*
4658  * lock_rwsem must be held for write
4659  */
4660 static void rbd_reacquire_lock(struct rbd_device *rbd_dev)
4661 {
4662         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
4663         char cookie[32];
4664         int ret;
4665 
4666         if (!rbd_quiesce_lock(rbd_dev))
4667                 return;
4668 
4669         format_lock_cookie(rbd_dev, cookie);
4670         ret = ceph_cls_set_cookie(osdc, &rbd_dev->header_oid,
4671                                   &rbd_dev->header_oloc, RBD_LOCK_NAME,
4672                                   CEPH_CLS_LOCK_EXCLUSIVE, rbd_dev->lock_cookie,
4673                                   RBD_LOCK_TAG, cookie);
4674         if (ret) {
4675                 if (ret != -EOPNOTSUPP)
4676                         rbd_warn(rbd_dev, "failed to update lock cookie: %d",
4677                                  ret);
4678 
4679                 /*
4680                  * Lock cookie cannot be updated on older OSDs, so do
4681                  * a manual release and queue an acquire.
4682                  */
4683                 __rbd_release_lock(rbd_dev);
4684                 queue_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork, 0);
4685         } else {
4686                 __rbd_lock(rbd_dev, cookie);
4687                 wake_lock_waiters(rbd_dev, 0);
4688         }
4689 }
4690 
4691 static void rbd_reregister_watch(struct work_struct *work)
4692 {
4693         struct rbd_device *rbd_dev = container_of(to_delayed_work(work),
4694                                             struct rbd_device, watch_dwork);
4695         int ret;
4696 
4697         dout("%s rbd_dev %p\n", __func__, rbd_dev);
4698 
4699         mutex_lock(&rbd_dev->watch_mutex);
4700         if (rbd_dev->watch_state != RBD_WATCH_STATE_ERROR) {
4701                 mutex_unlock(&rbd_dev->watch_mutex);
4702                 return;
4703         }
4704 
4705         ret = __rbd_register_watch(rbd_dev);
4706         if (ret) {
4707                 rbd_warn(rbd_dev, "failed to reregister watch: %d", ret);
4708                 if (ret != -EBLACKLISTED && ret != -ENOENT) {
4709                         queue_delayed_work(rbd_dev->task_wq,
4710                                            &rbd_dev->watch_dwork,
4711                                            RBD_RETRY_DELAY);
4712                         mutex_unlock(&rbd_dev->watch_mutex);
4713                         return;
4714                 }
4715 
4716                 mutex_unlock(&rbd_dev->watch_mutex);
4717                 down_write(&rbd_dev->lock_rwsem);
4718                 wake_lock_waiters(rbd_dev, ret);
4719                 up_write(&rbd_dev->lock_rwsem);
4720                 return;
4721         }
4722 
4723         rbd_dev->watch_state = RBD_WATCH_STATE_REGISTERED;
4724         rbd_dev->watch_cookie = rbd_dev->watch_handle->linger_id;
4725         mutex_unlock(&rbd_dev->watch_mutex);
4726 
4727         down_write(&rbd_dev->lock_rwsem);
4728         if (rbd_dev->lock_state == RBD_LOCK_STATE_LOCKED)
4729                 rbd_reacquire_lock(rbd_dev);
4730         up_write(&rbd_dev->lock_rwsem);
4731 
4732         ret = rbd_dev_refresh(rbd_dev);
4733         if (ret)
4734                 rbd_warn(rbd_dev, "reregistration refresh failed: %d", ret);
4735 }
4736 
4737 /*
4738  * Synchronous osd object method call.  Returns the number of bytes
4739  * returned in the outbound buffer, or a negative error code.
4740  */
4741 static int rbd_obj_method_sync(struct rbd_device *rbd_dev,
4742                              struct ceph_object_id *oid,
4743                              struct ceph_object_locator *oloc,
4744                              const char *method_name,
4745                              const void *outbound,
4746                              size_t outbound_size,
4747                              void *inbound,
4748                              size_t inbound_size)
4749 {
4750         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
4751         struct page *req_page = NULL;
4752         struct page *reply_page;
4753         int ret;
4754 
4755         /*
4756          * Method calls are ultimately read operations.  The result
4757          * should placed into the inbound buffer provided.  They
4758          * also supply outbound data--parameters for the object
4759          * method.  Currently if this is present it will be a
4760          * snapshot id.
4761          */
4762         if (outbound) {
4763                 if (outbound_size > PAGE_SIZE)
4764                         return -E2BIG;
4765 
4766                 req_page = alloc_page(GFP_KERNEL);
4767                 if (!req_page)
4768                         return -ENOMEM;
4769 
4770                 memcpy(page_address(req_page), outbound, outbound_size);
4771         }
4772 
4773         reply_page = alloc_page(GFP_KERNEL);
4774         if (!reply_page) {
4775                 if (req_page)
4776                         __free_page(req_page);
4777                 return -ENOMEM;
4778         }
4779 
4780         ret = ceph_osdc_call(osdc, oid, oloc, RBD_DRV_NAME, method_name,
4781                              CEPH_OSD_FLAG_READ, req_page, outbound_size,
4782                              &reply_page, &inbound_size);
4783         if (!ret) {
4784                 memcpy(inbound, page_address(reply_page), inbound_size);
4785                 ret = inbound_size;
4786         }
4787 
4788         if (req_page)
4789                 __free_page(req_page);
4790         __free_page(reply_page);
4791         return ret;
4792 }
4793 
4794 static void rbd_queue_workfn(struct work_struct *work)
4795 {
4796         struct request *rq = blk_mq_rq_from_pdu(work);
4797         struct rbd_device *rbd_dev = rq->q->queuedata;
4798         struct rbd_img_request *img_request;
4799         struct ceph_snap_context *snapc = NULL;
4800         u64 offset = (u64)blk_rq_pos(rq) << SECTOR_SHIFT;
4801         u64 length = blk_rq_bytes(rq);
4802         enum obj_operation_type op_type;
4803         u64 mapping_size;
4804         int result;
4805 
4806         switch (req_op(rq)) {
4807         case REQ_OP_DISCARD:
4808                 op_type = OBJ_OP_DISCARD;
4809                 break;
4810         case REQ_OP_WRITE_ZEROES:
4811                 op_type = OBJ_OP_ZEROOUT;
4812                 break;
4813         case REQ_OP_WRITE:
4814                 op_type = OBJ_OP_WRITE;
4815                 break;
4816         case REQ_OP_READ:
4817                 op_type = OBJ_OP_READ;
4818                 break;
4819         default:
4820                 dout("%s: non-fs request type %d\n", __func__, req_op(rq));
4821                 result = -EIO;
4822                 goto err;
4823         }
4824 
4825         /* Ignore/skip any zero-length requests */
4826 
4827         if (!length) {
4828                 dout("%s: zero-length request\n", __func__);
4829                 result = 0;
4830                 goto err_rq;
4831         }
4832 
4833         if (op_type != OBJ_OP_READ && rbd_dev->spec->snap_id != CEPH_NOSNAP) {
4834                 rbd_warn(rbd_dev, "%s on read-only snapshot",
4835                          obj_op_name(op_type));
4836                 result = -EIO;
4837                 goto err;
4838         }
4839 
4840         /*
4841          * Quit early if the mapped snapshot no longer exists.  It's
4842          * still possible the snapshot will have disappeared by the
4843          * time our request arrives at the osd, but there's no sense in
4844          * sending it if we already know.
4845          */
4846         if (!test_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags)) {
4847                 dout("request for non-existent snapshot");
4848                 rbd_assert(rbd_dev->spec->snap_id != CEPH_NOSNAP);
4849                 result = -ENXIO;
4850                 goto err_rq;
4851         }
4852 
4853         if (offset && length > U64_MAX - offset + 1) {
4854                 rbd_warn(rbd_dev, "bad request range (%llu~%llu)", offset,
4855                          length);
4856                 result = -EINVAL;
4857                 goto err_rq;    /* Shouldn't happen */
4858         }
4859 
4860         blk_mq_start_request(rq);
4861 
4862         down_read(&rbd_dev->header_rwsem);
4863         mapping_size = rbd_dev->mapping.size;
4864         if (op_type != OBJ_OP_READ) {
4865                 snapc = rbd_dev->header.snapc;
4866                 ceph_get_snap_context(snapc);
4867         }
4868         up_read(&rbd_dev->header_rwsem);
4869 
4870         if (offset + length > mapping_size) {
4871                 rbd_warn(rbd_dev, "beyond EOD (%llu~%llu > %llu)", offset,
4872                          length, mapping_size);
4873                 result = -EIO;
4874                 goto err_rq;
4875         }
4876 
4877         img_request = rbd_img_request_create(rbd_dev, op_type, snapc);
4878         if (!img_request) {
4879                 result = -ENOMEM;
4880                 goto err_rq;
4881         }
4882         img_request->rq = rq;
4883         snapc = NULL; /* img_request consumes a ref */
4884 
4885         dout("%s rbd_dev %p img_req %p %s %llu~%llu\n", __func__, rbd_dev,
4886              img_request, obj_op_name(op_type), offset, length);
4887 
4888         if (op_type == OBJ_OP_DISCARD || op_type == OBJ_OP_ZEROOUT)
4889                 result = rbd_img_fill_nodata(img_request, offset, length);
4890         else
4891                 result = rbd_img_fill_from_bio(img_request, offset, length,
4892                                                rq->bio);
4893         if (result)
4894                 goto err_img_request;
4895 
4896         rbd_img_handle_request(img_request, 0);
4897         return;
4898 
4899 err_img_request:
4900         rbd_img_request_put(img_request);
4901 err_rq:
4902         if (result)
4903                 rbd_warn(rbd_dev, "%s %llx at %llx result %d",
4904                          obj_op_name(op_type), length, offset, result);
4905         ceph_put_snap_context(snapc);
4906 err:
4907         blk_mq_end_request(rq, errno_to_blk_status(result));
4908 }
4909 
4910 static blk_status_t rbd_queue_rq(struct blk_mq_hw_ctx *hctx,
4911                 const struct blk_mq_queue_data *bd)
4912 {
4913         struct request *rq = bd->rq;
4914         struct work_struct *work = blk_mq_rq_to_pdu(rq);
4915 
4916         queue_work(rbd_wq, work);
4917         return BLK_STS_OK;
4918 }
4919 
4920 static void rbd_free_disk(struct rbd_device *rbd_dev)
4921 {
4922         blk_cleanup_queue(rbd_dev->disk->queue);
4923         blk_mq_free_tag_set(&rbd_dev->tag_set);
4924         put_disk(rbd_dev->disk);
4925         rbd_dev->disk = NULL;
4926 }
4927 
4928 static int rbd_obj_read_sync(struct rbd_device *rbd_dev,
4929                              struct ceph_object_id *oid,
4930                              struct ceph_object_locator *oloc,
4931                              void *buf, int buf_len)
4932 
4933 {
4934         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
4935         struct ceph_osd_request *req;
4936         struct page **pages;
4937         int num_pages = calc_pages_for(0, buf_len);
4938         int ret;
4939 
4940         req = ceph_osdc_alloc_request(osdc, NULL, 1, false, GFP_KERNEL);
4941         if (!req)
4942                 return -ENOMEM;
4943 
4944         ceph_oid_copy(&req->r_base_oid, oid);
4945         ceph_oloc_copy(&req->r_base_oloc, oloc);
4946         req->r_flags = CEPH_OSD_FLAG_READ;
4947 
4948         pages = ceph_alloc_page_vector(num_pages, GFP_KERNEL);
4949         if (IS_ERR(pages)) {
4950                 ret = PTR_ERR(pages);
4951                 goto out_req;
4952         }
4953 
4954         osd_req_op_extent_init(req, 0, CEPH_OSD_OP_READ, 0, buf_len, 0, 0);
4955         osd_req_op_extent_osd_data_pages(req, 0, pages, buf_len, 0, false,
4956                                          true);
4957 
4958         ret = ceph_osdc_alloc_messages(req, GFP_KERNEL);
4959         if (ret)
4960                 goto out_req;
4961 
4962         ceph_osdc_start_request(osdc, req, false);
4963         ret = ceph_osdc_wait_request(osdc, req);
4964         if (ret >= 0)
4965                 ceph_copy_from_page_vector(pages, buf, 0, ret);
4966 
4967 out_req:
4968         ceph_osdc_put_request(req);
4969         return ret;
4970 }
4971 
4972 /*
4973  * Read the complete header for the given rbd device.  On successful
4974  * return, the rbd_dev->header field will contain up-to-date
4975  * information about the image.
4976  */
4977 static int rbd_dev_v1_header_info(struct rbd_device *rbd_dev)
4978 {
4979         struct rbd_image_header_ondisk *ondisk = NULL;
4980         u32 snap_count = 0;
4981         u64 names_size = 0;
4982         u32 want_count;
4983         int ret;
4984 
4985         /*
4986          * The complete header will include an array of its 64-bit
4987          * snapshot ids, followed by the names of those snapshots as
4988          * a contiguous block of NUL-terminated strings.  Note that
4989          * the number of snapshots could change by the time we read
4990          * it in, in which case we re-read it.
4991          */
4992         do {
4993                 size_t size;
4994 
4995                 kfree(ondisk);
4996 
4997                 size = sizeof (*ondisk);
4998                 size += snap_count * sizeof (struct rbd_image_snap_ondisk);
4999                 size += names_size;
5000                 ondisk = kmalloc(size, GFP_KERNEL);
5001                 if (!ondisk)
5002                         return -ENOMEM;
5003 
5004                 ret = rbd_obj_read_sync(rbd_dev, &rbd_dev->header_oid,
5005                                         &rbd_dev->header_oloc, ondisk, size);
5006                 if (ret < 0)
5007                         goto out;
5008                 if ((size_t)ret < size) {
5009                         ret = -ENXIO;
5010                         rbd_warn(rbd_dev, "short header read (want %zd got %d)",
5011                                 size, ret);
5012                         goto out;
5013                 }
5014                 if (!rbd_dev_ondisk_valid(ondisk)) {
5015                         ret = -ENXIO;
5016                         rbd_warn(rbd_dev, "invalid header");
5017                         goto out;
5018                 }
5019 
5020                 names_size = le64_to_cpu(ondisk->snap_names_len);
5021                 want_count = snap_count;
5022                 snap_count = le32_to_cpu(ondisk->snap_count);
5023         } while (snap_count != want_count);
5024 
5025         ret = rbd_header_from_disk(rbd_dev, ondisk);
5026 out:
5027         kfree(ondisk);
5028 
5029         return ret;
5030 }
5031 
5032 /*
5033  * Clear the rbd device's EXISTS flag if the snapshot it's mapped to
5034  * has disappeared from the (just updated) snapshot context.
5035  */
5036 static void rbd_exists_validate(struct rbd_device *rbd_dev)
5037 {
5038         u64 snap_id;
5039 
5040         if (!test_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags))
5041                 return;
5042 
5043         snap_id = rbd_dev->spec->snap_id;
5044         if (snap_id == CEPH_NOSNAP)
5045                 return;
5046 
5047         if (rbd_dev_snap_index(rbd_dev, snap_id) == BAD_SNAP_INDEX)
5048                 clear_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags);
5049 }
5050 
5051 static void rbd_dev_update_size(struct rbd_device *rbd_dev)
5052 {
5053         sector_t size;
5054 
5055         /*
5056          * If EXISTS is not set, rbd_dev->disk may be NULL, so don't
5057          * try to update its size.  If REMOVING is set, updating size
5058          * is just useless work since the device can't be opened.
5059          */
5060         if (test_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags) &&
5061             !test_bit(RBD_DEV_FLAG_REMOVING, &rbd_dev->flags)) {
5062                 size = (sector_t)rbd_dev->mapping.size / SECTOR_SIZE;
5063                 dout("setting size to %llu sectors", (unsigned long long)size);
5064                 set_capacity(rbd_dev->disk, size);
5065                 revalidate_disk(rbd_dev->disk);
5066         }
5067 }
5068 
5069 static int rbd_dev_refresh(struct rbd_device *rbd_dev)
5070 {
5071         u64 mapping_size;
5072         int ret;
5073 
5074         down_write(&rbd_dev->header_rwsem);
5075         mapping_size = rbd_dev->mapping.size;
5076 
5077         ret = rbd_dev_header_info(rbd_dev);
5078         if (ret)
5079                 goto out;
5080 
5081         /*
5082          * If there is a parent, see if it has disappeared due to the
5083          * mapped image getting flattened.
5084          */
5085         if (rbd_dev->parent) {
5086                 ret = rbd_dev_v2_parent_info(rbd_dev);
5087                 if (ret)
5088                         goto out;
5089         }
5090 
5091         if (rbd_dev->spec->snap_id == CEPH_NOSNAP) {
5092                 rbd_dev->mapping.size = rbd_dev->header.image_size;
5093         } else {
5094                 /* validate mapped snapshot's EXISTS flag */
5095                 rbd_exists_validate(rbd_dev);
5096         }
5097 
5098 out:
5099         up_write(&rbd_dev->header_rwsem);
5100         if (!ret && mapping_size != rbd_dev->mapping.size)
5101                 rbd_dev_update_size(rbd_dev);
5102 
5103         return ret;
5104 }
5105 
5106 static int rbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
5107                 unsigned int hctx_idx, unsigned int numa_node)
5108 {
5109         struct work_struct *work = blk_mq_rq_to_pdu(rq);
5110 
5111         INIT_WORK(work, rbd_queue_workfn);
5112         return 0;
5113 }
5114 
5115 static const struct blk_mq_ops rbd_mq_ops = {
5116         .queue_rq       = rbd_queue_rq,
5117         .init_request   = rbd_init_request,
5118 };
5119 
5120 static int rbd_init_disk(struct rbd_device *rbd_dev)
5121 {
5122         struct gendisk *disk;
5123         struct request_queue *q;
5124         unsigned int objset_bytes =
5125             rbd_dev->layout.object_size * rbd_dev->layout.stripe_count;
5126         int err;
5127 
5128         /* create gendisk info */
5129         disk = alloc_disk(single_major ?
5130                           (1 << RBD_SINGLE_MAJOR_PART_SHIFT) :
5131                           RBD_MINORS_PER_MAJOR);
5132         if (!disk)
5133                 return -ENOMEM;
5134 
5135         snprintf(disk->disk_name, sizeof(disk->disk_name), RBD_DRV_NAME "%d",
5136                  rbd_dev->dev_id);
5137         disk->major = rbd_dev->major;
5138         disk->first_minor = rbd_dev->minor;
5139         if (single_major)
5140                 disk->flags |= GENHD_FL_EXT_DEVT;
5141         disk->fops = &rbd_bd_ops;
5142         disk->private_data = rbd_dev;
5143 
5144         memset(&rbd_dev->tag_set, 0, sizeof(rbd_dev->tag_set));
5145         rbd_dev->tag_set.ops = &rbd_mq_ops;
5146         rbd_dev->tag_set.queue_depth = rbd_dev->opts->queue_depth;
5147         rbd_dev->tag_set.numa_node = NUMA_NO_NODE;
5148         rbd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
5149         rbd_dev->tag_set.nr_hw_queues = 1;
5150         rbd_dev->tag_set.cmd_size = sizeof(struct work_struct);
5151 
5152         err = blk_mq_alloc_tag_set(&rbd_dev->tag_set);
5153         if (err)
5154                 goto out_disk;
5155 
5156         q = blk_mq_init_queue(&rbd_dev->tag_set);
5157         if (IS_ERR(q)) {
5158                 err = PTR_ERR(q);
5159                 goto out_tag_set;
5160         }
5161 
5162         blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
5163         /* QUEUE_FLAG_ADD_RANDOM is off by default for blk-mq */
5164 
5165         blk_queue_max_hw_sectors(q, objset_bytes >> SECTOR_SHIFT);
5166         q->limits.max_sectors = queue_max_hw_sectors(q);
5167         blk_queue_max_segments(q, USHRT_MAX);
5168         blk_queue_max_segment_size(q, UINT_MAX);
5169         blk_queue_io_min(q, rbd_dev->opts->alloc_size);
5170         blk_queue_io_opt(q, rbd_dev->opts->alloc_size);
5171 
5172         if (rbd_dev->opts->trim) {
5173                 blk_queue_flag_set(QUEUE_FLAG_DISCARD, q);
5174                 q->limits.discard_granularity = rbd_dev->opts->alloc_size;
5175                 blk_queue_max_discard_sectors(q, objset_bytes >> SECTOR_SHIFT);
5176                 blk_queue_max_write_zeroes_sectors(q, objset_bytes >> SECTOR_SHIFT);
5177         }
5178 
5179         if (!ceph_test_opt(rbd_dev->rbd_client->client, NOCRC))
5180                 q->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES;
5181 
5182         /*
5183          * disk_release() expects a queue ref from add_disk() and will
5184          * put it.  Hold an extra ref until add_disk() is called.
5185          */
5186         WARN_ON(!blk_get_queue(q));
5187         disk->queue = q;
5188         q->queuedata = rbd_dev;
5189 
5190         rbd_dev->disk = disk;
5191 
5192         return 0;
5193 out_tag_set:
5194         blk_mq_free_tag_set(&rbd_dev->tag_set);
5195 out_disk:
5196         put_disk(disk);
5197         return err;
5198 }
5199 
5200 /*
5201   sysfs
5202 */
5203 
5204 static struct rbd_device *dev_to_rbd_dev(struct device *dev)
5205 {
5206         return container_of(dev, struct rbd_device, dev);
5207 }
5208 
5209 static ssize_t rbd_size_show(struct device *dev,
5210                              struct device_attribute *attr, char *buf)
5211 {
5212         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5213 
5214         return sprintf(buf, "%llu\n",
5215                 (unsigned long long)rbd_dev->mapping.size);
5216 }
5217 
5218 /*
5219  * Note this shows the features for whatever's mapped, which is not
5220  * necessarily the base image.
5221  */
5222 static ssize_t rbd_features_show(struct device *dev,
5223                              struct device_attribute *attr, char *buf)
5224 {
5225         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5226 
5227         return sprintf(buf, "0x%016llx\n",
5228                         (unsigned long long)rbd_dev->mapping.features);
5229 }
5230 
5231 static ssize_t rbd_major_show(struct device *dev,
5232                               struct device_attribute *attr, char *buf)
5233 {
5234         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5235 
5236         if (rbd_dev->major)
5237                 return sprintf(buf, "%d\n", rbd_dev->major);
5238 
5239         return sprintf(buf, "(none)\n");
5240 }
5241 
5242 static ssize_t rbd_minor_show(struct device *dev,
5243                               struct device_attribute *attr, char *buf)
5244 {
5245         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5246 
5247         return sprintf(buf, "%d\n", rbd_dev->minor);
5248 }
5249 
5250 static ssize_t rbd_client_addr_show(struct device *dev,
5251                                     struct device_attribute *attr, char *buf)
5252 {
5253         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5254         struct ceph_entity_addr *client_addr =
5255             ceph_client_addr(rbd_dev->rbd_client->client);
5256 
5257         return sprintf(buf, "%pISpc/%u\n", &client_addr->in_addr,
5258                        le32_to_cpu(client_addr->nonce));
5259 }
5260 
5261 static ssize_t rbd_client_id_show(struct device *dev,
5262                                   struct device_attribute *attr, char *buf)
5263 {
5264         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5265 
5266         return sprintf(buf, "client%lld\n",
5267                        ceph_client_gid(rbd_dev->rbd_client->client));
5268 }
5269 
5270 static ssize_t rbd_cluster_fsid_show(struct device *dev,
5271                                      struct device_attribute *attr, char *buf)
5272 {
5273         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5274 
5275         return sprintf(buf, "%pU\n", &rbd_dev->rbd_client->client->fsid);
5276 }
5277 
5278 static ssize_t rbd_config_info_show(struct device *dev,
5279                                     struct device_attribute *attr, char *buf)
5280 {
5281         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5282 
5283         return sprintf(buf, "%s\n", rbd_dev->config_info);
5284 }
5285 
5286 static ssize_t rbd_pool_show(struct device *dev,
5287                              struct device_attribute *attr, char *buf)
5288 {
5289         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5290 
5291         return sprintf(buf, "%s\n", rbd_dev->spec->pool_name);
5292 }
5293 
5294 static ssize_t rbd_pool_id_show(struct device *dev,
5295                              struct device_attribute *attr, char *buf)
5296 {
5297         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5298 
5299         return sprintf(buf, "%llu\n",
5300                         (unsigned long long) rbd_dev->spec->pool_id);
5301 }
5302 
5303 static ssize_t rbd_pool_ns_show(struct device *dev,
5304                                 struct device_attribute *attr, char *buf)
5305 {
5306         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5307 
5308         return sprintf(buf, "%s\n", rbd_dev->spec->pool_ns ?: "");
5309 }
5310 
5311 static ssize_t rbd_name_show(struct device *dev,
5312                              struct device_attribute *attr, char *buf)
5313 {
5314         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5315 
5316         if (rbd_dev->spec->image_name)
5317                 return sprintf(buf, "%s\n", rbd_dev->spec->image_name);
5318 
5319         return sprintf(buf, "(unknown)\n");
5320 }
5321 
5322 static ssize_t rbd_image_id_show(struct device *dev,
5323                              struct device_attribute *attr, char *buf)
5324 {
5325         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5326 
5327         return sprintf(buf, "%s\n", rbd_dev->spec->image_id);
5328 }
5329 
5330 /*
5331  * Shows the name of the currently-mapped snapshot (or
5332  * RBD_SNAP_HEAD_NAME for the base image).
5333  */
5334 static ssize_t rbd_snap_show(struct device *dev,
5335                              struct device_attribute *attr,
5336                              char *buf)
5337 {
5338         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5339 
5340         return sprintf(buf, "%s\n", rbd_dev->spec->snap_name);
5341 }
5342 
5343 static ssize_t rbd_snap_id_show(struct device *dev,
5344                                 struct device_attribute *attr, char *buf)
5345 {
5346         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5347 
5348         return sprintf(buf, "%llu\n", rbd_dev->spec->snap_id);
5349 }
5350 
5351 /*
5352  * For a v2 image, shows the chain of parent images, separated by empty
5353  * lines.  For v1 images or if there is no parent, shows "(no parent
5354  * image)".
5355  */
5356 static ssize_t rbd_parent_show(struct device *dev,
5357                                struct device_attribute *attr,
5358                                char *buf)
5359 {
5360         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5361         ssize_t count = 0;
5362 
5363         if (!rbd_dev->parent)
5364                 return sprintf(buf, "(no parent image)\n");
5365 
5366         for ( ; rbd_dev->parent; rbd_dev = rbd_dev->parent) {
5367                 struct rbd_spec *spec = rbd_dev->parent_spec;
5368 
5369                 count += sprintf(&buf[count], "%s"
5370                             "pool_id %llu\npool_name %s\n"
5371                             "pool_ns %s\n"
5372                             "image_id %s\nimage_name %s\n"
5373                             "snap_id %llu\nsnap_name %s\n"
5374                             "overlap %llu\n",
5375                             !count ? "" : "\n", /* first? */
5376                             spec->pool_id, spec->pool_name,
5377                             spec->pool_ns ?: "",
5378                             spec->image_id, spec->image_name ?: "(unknown)",
5379                             spec->snap_id, spec->snap_name,
5380                             rbd_dev->parent_overlap);
5381         }
5382 
5383         return count;
5384 }
5385 
5386 static ssize_t rbd_image_refresh(struct device *dev,
5387                                  struct device_attribute *attr,
5388                                  const char *buf,
5389                                  size_t size)
5390 {
5391         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5392         int ret;
5393 
5394         ret = rbd_dev_refresh(rbd_dev);
5395         if (ret)
5396                 return ret;
5397 
5398         return size;
5399 }
5400 
5401 static DEVICE_ATTR(size, 0444, rbd_size_show, NULL);
5402 static DEVICE_ATTR(features, 0444, rbd_features_show, NULL);
5403 static DEVICE_ATTR(major, 0444, rbd_major_show, NULL);
5404 static DEVICE_ATTR(minor, 0444, rbd_minor_show, NULL);
5405 static DEVICE_ATTR(client_addr, 0444, rbd_client_addr_show, NULL);
5406 static DEVICE_ATTR(client_id, 0444, rbd_client_id_show, NULL);
5407 static DEVICE_ATTR(cluster_fsid, 0444, rbd_cluster_fsid_show, NULL);
5408 static DEVICE_ATTR(config_info, 0400, rbd_config_info_show, NULL);
5409 static DEVICE_ATTR(pool, 0444, rbd_pool_show, NULL);
5410 static DEVICE_ATTR(pool_id, 0444, rbd_pool_id_show, NULL);
5411 static DEVICE_ATTR(pool_ns, 0444, rbd_pool_ns_show, NULL);
5412 static DEVICE_ATTR(name, 0444, rbd_name_show, NULL);
5413 static DEVICE_ATTR(image_id, 0444, rbd_image_id_show, NULL);
5414 static DEVICE_ATTR(refresh, 0200, NULL, rbd_image_refresh);
5415 static DEVICE_ATTR(current_snap, 0444, rbd_snap_show, NULL);
5416 static DEVICE_ATTR(snap_id, 0444, rbd_snap_id_show, NULL);
5417 static DEVICE_ATTR(parent, 0444, rbd_parent_show, NULL);
5418 
5419 static struct attribute *rbd_attrs[] = {
5420         &dev_attr_size.attr,
5421         &dev_attr_features.attr,
5422         &dev_attr_major.attr,
5423         &dev_attr_minor.attr,
5424         &dev_attr_client_addr.attr,
5425         &dev_attr_client_id.attr,
5426         &dev_attr_cluster_fsid.attr,
5427         &dev_attr_config_info.attr,
5428         &dev_attr_pool.attr,
5429         &dev_attr_pool_id.attr,
5430         &dev_attr_pool_ns.attr,
5431         &dev_attr_name.attr,
5432         &dev_attr_image_id.attr,
5433         &dev_attr_current_snap.attr,
5434         &dev_attr_snap_id.attr,
5435         &dev_attr_parent.attr,
5436         &dev_attr_refresh.attr,
5437         NULL
5438 };
5439 
5440 static struct attribute_group rbd_attr_group = {
5441         .attrs = rbd_attrs,
5442 };
5443 
5444 static const struct attribute_group *rbd_attr_groups[] = {
5445         &rbd_attr_group,
5446         NULL
5447 };
5448 
5449 static void rbd_dev_release(struct device *dev);
5450 
5451 static const struct device_type rbd_device_type = {
5452         .name           = "rbd",
5453         .groups         = rbd_attr_groups,
5454         .release        = rbd_dev_release,
5455 };
5456 
5457 static struct rbd_spec *rbd_spec_get(struct rbd_spec *spec)
5458 {
5459         kref_get(&spec->kref);
5460 
5461         return spec;
5462 }
5463 
5464 static void rbd_spec_free(struct kref *kref);
5465 static void rbd_spec_put(struct rbd_spec *spec)
5466 {
5467         if (spec)
5468                 kref_put(&spec->kref, rbd_spec_free);
5469 }
5470 
5471 static struct rbd_spec *rbd_spec_alloc(void)
5472 {
5473         struct rbd_spec *spec;
5474 
5475         spec = kzalloc(sizeof (*spec), GFP_KERNEL);
5476         if (!spec)
5477                 return NULL;
5478 
5479         spec->pool_id = CEPH_NOPOOL;
5480         spec->snap_id = CEPH_NOSNAP;
5481         kref_init(&spec->kref);
5482 
5483         return spec;
5484 }
5485 
5486 static void rbd_spec_free(struct kref *kref)
5487 {
5488         struct rbd_spec *spec = container_of(kref, struct rbd_spec, kref);
5489 
5490         kfree(spec->pool_name);
5491         kfree(spec->pool_ns);
5492         kfree(spec->image_id);
5493         kfree(spec->image_name);
5494         kfree(spec->snap_name);
5495         kfree(spec);
5496 }
5497 
5498 static void rbd_dev_free(struct rbd_device *rbd_dev)
5499 {
5500         WARN_ON(rbd_dev->watch_state != RBD_WATCH_STATE_UNREGISTERED);
5501         WARN_ON(rbd_dev->lock_state != RBD_LOCK_STATE_UNLOCKED);
5502 
5503         ceph_oid_destroy(&rbd_dev->header_oid);
5504         ceph_oloc_destroy(&rbd_dev->header_oloc);
5505         kfree(rbd_dev->config_info);
5506 
5507         rbd_put_client(rbd_dev->rbd_client);
5508         rbd_spec_put(rbd_dev->spec);
5509         kfree(rbd_dev->opts);
5510         kfree(rbd_dev);
5511 }
5512 
5513 static void rbd_dev_release(struct device *dev)
5514 {
5515         struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
5516         bool need_put = !!rbd_dev->opts;
5517 
5518         if (need_put) {
5519                 destroy_workqueue(rbd_dev->task_wq);
5520                 ida_simple_remove(&rbd_dev_id_ida, rbd_dev->dev_id);
5521         }
5522 
5523         rbd_dev_free(rbd_dev);
5524 
5525         /*
5526          * This is racy, but way better than putting module outside of
5527          * the release callback.  The race window is pretty small, so
5528          * doing something similar to dm (dm-builtin.c) is overkill.
5529          */
5530         if (need_put)
5531                 module_put(THIS_MODULE);
5532 }
5533 
5534 static struct rbd_device *__rbd_dev_create(struct rbd_client *rbdc,
5535                                            struct rbd_spec *spec)
5536 {
5537         struct rbd_device *rbd_dev;
5538 
5539         rbd_dev = kzalloc(sizeof(*rbd_dev), GFP_KERNEL);
5540         if (!rbd_dev)
5541                 return NULL;
5542 
5543         spin_lock_init(&rbd_dev->lock);
5544         INIT_LIST_HEAD(&rbd_dev->node);
5545         init_rwsem(&rbd_dev->header_rwsem);
5546 
5547         rbd_dev->header.data_pool_id = CEPH_NOPOOL;
5548         ceph_oid_init(&rbd_dev->header_oid);
5549         rbd_dev->header_oloc.pool = spec->pool_id;
5550         if (spec->pool_ns) {
5551                 WARN_ON(!*spec->pool_ns);
5552                 rbd_dev->header_oloc.pool_ns =
5553                     ceph_find_or_create_string(spec->pool_ns,
5554                                                strlen(spec->pool_ns));
5555         }
5556 
5557         mutex_init(&rbd_dev->watch_mutex);
5558         rbd_dev->watch_state = RBD_WATCH_STATE_UNREGISTERED;
5559         INIT_DELAYED_WORK(&rbd_dev->watch_dwork, rbd_reregister_watch);
5560 
5561         init_rwsem(&rbd_dev->lock_rwsem);
5562         rbd_dev->lock_state = RBD_LOCK_STATE_UNLOCKED;
5563         INIT_WORK(&rbd_dev->acquired_lock_work, rbd_notify_acquired_lock);
5564         INIT_WORK(&rbd_dev->released_lock_work, rbd_notify_released_lock);
5565         INIT_DELAYED_WORK(&rbd_dev->lock_dwork, rbd_acquire_lock);
5566         INIT_WORK(&rbd_dev->unlock_work, rbd_release_lock_work);
5567         spin_lock_init(&rbd_dev->lock_lists_lock);
5568         INIT_LIST_HEAD(&rbd_dev->acquiring_list);
5569         INIT_LIST_HEAD(&rbd_dev->running_list);
5570         init_completion(&rbd_dev->acquire_wait);
5571         init_completion(&rbd_dev->releasing_wait);
5572 
5573         spin_lock_init(&rbd_dev->object_map_lock);
5574 
5575         rbd_dev->dev.bus = &rbd_bus_type;
5576         rbd_dev->dev.type = &rbd_device_type;
5577         rbd_dev->dev.parent = &rbd_root_dev;
5578         device_initialize(&rbd_dev->dev);
5579 
5580         rbd_dev->rbd_client = rbdc;
5581         rbd_dev->spec = spec;
5582 
5583         return rbd_dev;
5584 }
5585 
5586 /*
5587  * Create a mapping rbd_dev.
5588  */
5589 static struct rbd_device *rbd_dev_create(struct rbd_client *rbdc,
5590                                          struct rbd_spec *spec,
5591                                          struct rbd_options *opts)
5592 {
5593         struct rbd_device *rbd_dev;
5594 
5595         rbd_dev = __rbd_dev_create(rbdc, spec);
5596         if (!rbd_dev)
5597                 return NULL;
5598 
5599         rbd_dev->opts = opts;
5600 
5601         /* get an id and fill in device name */
5602         rbd_dev->dev_id = ida_simple_get(&rbd_dev_id_ida, 0,
5603                                          minor_to_rbd_dev_id(1 << MINORBITS),
5604                                          GFP_KERNEL);
5605         if (rbd_dev->dev_id < 0)
5606                 goto fail_rbd_dev;
5607 
5608         sprintf(rbd_dev->name, RBD_DRV_NAME "%d", rbd_dev->dev_id);
5609         rbd_dev->task_wq = alloc_ordered_workqueue("%s-tasks", WQ_MEM_RECLAIM,
5610                                                    rbd_dev->name);
5611         if (!rbd_dev->task_wq)
5612                 goto fail_dev_id;
5613 
5614         /* we have a ref from do_rbd_add() */
5615         __module_get(THIS_MODULE);
5616 
5617         dout("%s rbd_dev %p dev_id %d\n", __func__, rbd_dev, rbd_dev->dev_id);
5618         return rbd_dev;
5619 
5620 fail_dev_id:
5621         ida_simple_remove(&rbd_dev_id_ida, rbd_dev->dev_id);
5622 fail_rbd_dev:
5623         rbd_dev_free(rbd_dev);
5624         return NULL;
5625 }
5626 
5627 static void rbd_dev_destroy(struct rbd_device *rbd_dev)
5628 {
5629         if (rbd_dev)
5630                 put_device(&rbd_dev->dev);
5631 }
5632 
5633 /*
5634  * Get the size and object order for an image snapshot, or if
5635  * snap_id is CEPH_NOSNAP, gets this information for the base
5636  * image.
5637  */
5638 static int _rbd_dev_v2_snap_size(struct rbd_device *rbd_dev, u64 snap_id,
5639                                 u8 *order, u64 *snap_size)
5640 {
5641         __le64 snapid = cpu_to_le64(snap_id);
5642         int ret;
5643         struct {
5644                 u8 order;
5645                 __le64 size;
5646         } __attribute__ ((packed)) size_buf = { 0 };
5647 
5648         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
5649                                   &rbd_dev->header_oloc, "get_size",
5650                                   &snapid, sizeof(snapid),
5651                                   &size_buf, sizeof(size_buf));
5652         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
5653         if (ret < 0)
5654                 return ret;
5655         if (ret < sizeof (size_buf))
5656                 return -ERANGE;
5657 
5658         if (order) {
5659                 *order = size_buf.order;
5660                 dout("  order %u", (unsigned int)*order);
5661         }
5662         *snap_size = le64_to_cpu(size_buf.size);
5663 
5664         dout("  snap_id 0x%016llx snap_size = %llu\n",
5665                 (unsigned long long)snap_id,
5666                 (unsigned long long)*snap_size);
5667 
5668         return 0;
5669 }
5670 
5671 static int rbd_dev_v2_image_size(struct rbd_device *rbd_dev)
5672 {
5673         return _rbd_dev_v2_snap_size(rbd_dev, CEPH_NOSNAP,
5674                                         &rbd_dev->header.obj_order,
5675                                         &rbd_dev->header.image_size);
5676 }
5677 
5678 static int rbd_dev_v2_object_prefix(struct rbd_device *rbd_dev)
5679 {
5680         size_t size;
5681         void *reply_buf;
5682         int ret;
5683         void *p;
5684 
5685         /* Response will be an encoded string, which includes a length */
5686         size = sizeof(__le32) + RBD_OBJ_PREFIX_LEN_MAX;
5687         reply_buf = kzalloc(size, GFP_KERNEL);
5688         if (!reply_buf)
5689                 return -ENOMEM;
5690 
5691         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
5692                                   &rbd_dev->header_oloc, "get_object_prefix",
5693                                   NULL, 0, reply_buf, size);
5694         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
5695         if (ret < 0)
5696                 goto out;
5697 
5698         p = reply_buf;
5699         rbd_dev->header.object_prefix = ceph_extract_encoded_string(&p,
5700                                                 p + ret, NULL, GFP_NOIO);
5701         ret = 0;
5702 
5703         if (IS_ERR(rbd_dev->header.object_prefix)) {
5704                 ret = PTR_ERR(rbd_dev->header.object_prefix);
5705                 rbd_dev->header.object_prefix = NULL;
5706         } else {
5707                 dout("  object_prefix = %s\n", rbd_dev->header.object_prefix);
5708         }
5709 out:
5710         kfree(reply_buf);
5711 
5712         return ret;
5713 }
5714 
5715 static int _rbd_dev_v2_snap_features(struct rbd_device *rbd_dev, u64 snap_id,
5716                 u64 *snap_features)
5717 {
5718         __le64 snapid = cpu_to_le64(snap_id);
5719         struct {
5720                 __le64 features;
5721                 __le64 incompat;
5722         } __attribute__ ((packed)) features_buf = { 0 };
5723         u64 unsup;
5724         int ret;
5725 
5726         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
5727                                   &rbd_dev->header_oloc, "get_features",
5728                                   &snapid, sizeof(snapid),
5729                                   &features_buf, sizeof(features_buf));
5730         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
5731         if (ret < 0)
5732                 return ret;
5733         if (ret < sizeof (features_buf))
5734                 return -ERANGE;
5735 
5736         unsup = le64_to_cpu(features_buf.incompat) & ~RBD_FEATURES_SUPPORTED;
5737         if (unsup) {
5738                 rbd_warn(rbd_dev, "image uses unsupported features: 0x%llx",
5739                          unsup);
5740                 return -ENXIO;
5741         }
5742 
5743         *snap_features = le64_to_cpu(features_buf.features);
5744 
5745         dout("  snap_id 0x%016llx features = 0x%016llx incompat = 0x%016llx\n",
5746                 (unsigned long long)snap_id,
5747                 (unsigned long long)*snap_features,
5748                 (unsigned long long)le64_to_cpu(features_buf.incompat));
5749 
5750         return 0;
5751 }
5752 
5753 static int rbd_dev_v2_features(struct rbd_device *rbd_dev)
5754 {
5755         return _rbd_dev_v2_snap_features(rbd_dev, CEPH_NOSNAP,
5756                                                 &rbd_dev->header.features);
5757 }
5758 
5759 /*
5760  * These are generic image flags, but since they are used only for
5761  * object map, store them in rbd_dev->object_map_flags.
5762  *
5763  * For the same reason, this function is called only on object map
5764  * (re)load and not on header refresh.
5765  */
5766 static int rbd_dev_v2_get_flags(struct rbd_device *rbd_dev)
5767 {
5768         __le64 snapid = cpu_to_le64(rbd_dev->spec->snap_id);
5769         __le64 flags;
5770         int ret;
5771 
5772         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
5773                                   &rbd_dev->header_oloc, "get_flags",
5774                                   &snapid, sizeof(snapid),
5775                                   &flags, sizeof(flags));
5776         if (ret < 0)
5777                 return ret;
5778         if (ret < sizeof(flags))
5779                 return -EBADMSG;
5780 
5781         rbd_dev->object_map_flags = le64_to_cpu(flags);
5782         return 0;
5783 }
5784 
5785 struct parent_image_info {
5786         u64             pool_id;
5787         const char      *pool_ns;
5788         const char      *image_id;
5789         u64             snap_id;
5790 
5791         bool            has_overlap;
5792         u64             overlap;
5793 };
5794 
5795 /*
5796  * The caller is responsible for @pii.
5797  */
5798 static int decode_parent_image_spec(void **p, void *end,
5799                                     struct parent_image_info *pii)
5800 {
5801         u8 struct_v;
5802         u32 struct_len;
5803         int ret;
5804 
5805         ret = ceph_start_decoding(p, end, 1, "ParentImageSpec",
5806                                   &struct_v, &struct_len);
5807         if (ret)
5808                 return ret;
5809 
5810         ceph_decode_64_safe(p, end, pii->pool_id, e_inval);
5811         pii->pool_ns = ceph_extract_encoded_string(p, end, NULL, GFP_KERNEL);
5812         if (IS_ERR(pii->pool_ns)) {
5813                 ret = PTR_ERR(pii->pool_ns);
5814                 pii->pool_ns = NULL;
5815                 return ret;
5816         }
5817         pii->image_id = ceph_extract_encoded_string(p, end, NULL, GFP_KERNEL);
5818         if (IS_ERR(pii->image_id)) {
5819                 ret = PTR_ERR(pii->image_id);
5820                 pii->image_id = NULL;
5821                 return ret;
5822         }
5823         ceph_decode_64_safe(p, end, pii->snap_id, e_inval);
5824         return 0;
5825 
5826 e_inval:
5827         return -EINVAL;
5828 }
5829 
5830 static int __get_parent_info(struct rbd_device *rbd_dev,
5831                              struct page *req_page,
5832                              struct page *reply_page,
5833                              struct parent_image_info *pii)
5834 {
5835         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
5836         size_t reply_len = PAGE_SIZE;
5837         void *p, *end;
5838         int ret;
5839 
5840         ret = ceph_osdc_call(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
5841                              "rbd", "parent_get", CEPH_OSD_FLAG_READ,
5842                              req_page, sizeof(u64), &reply_page, &reply_len);
5843         if (ret)
5844                 return ret == -EOPNOTSUPP ? 1 : ret;
5845 
5846         p = page_address(reply_page);
5847         end = p + reply_len;
5848         ret = decode_parent_image_spec(&p, end, pii);
5849         if (ret)
5850                 return ret;
5851 
5852         ret = ceph_osdc_call(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
5853                              "rbd", "parent_overlap_get", CEPH_OSD_FLAG_READ,
5854                              req_page, sizeof(u64), &reply_page, &reply_len);
5855         if (ret)
5856                 return ret;
5857 
5858         p = page_address(reply_page);
5859         end = p + reply_len;
5860         ceph_decode_8_safe(&p, end, pii->has_overlap, e_inval);
5861         if (pii->has_overlap)
5862                 ceph_decode_64_safe(&p, end, pii->overlap, e_inval);
5863 
5864         return 0;
5865 
5866 e_inval:
5867         return -EINVAL;
5868 }
5869 
5870 /*
5871  * The caller is responsible for @pii.
5872  */
5873 static int __get_parent_info_legacy(struct rbd_device *rbd_dev,
5874                                     struct page *req_page,
5875                                     struct page *reply_page,
5876                                     struct parent_image_info *pii)
5877 {
5878         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
5879         size_t reply_len = PAGE_SIZE;
5880         void *p, *end;
5881         int ret;
5882 
5883         ret = ceph_osdc_call(osdc, &rbd_dev->header_oid, &rbd_dev->header_oloc,
5884                              "rbd", "get_parent", CEPH_OSD_FLAG_READ,
5885                              req_page, sizeof(u64), &reply_page, &reply_len);
5886         if (ret)
5887                 return ret;
5888 
5889         p = page_address(reply_page);
5890         end = p + reply_len;
5891         ceph_decode_64_safe(&p, end, pii->pool_id, e_inval);
5892         pii->image_id = ceph_extract_encoded_string(&p, end, NULL, GFP_KERNEL);
5893         if (IS_ERR(pii->image_id)) {
5894                 ret = PTR_ERR(pii->image_id);
5895                 pii->image_id = NULL;
5896                 return ret;
5897         }
5898         ceph_decode_64_safe(&p, end, pii->snap_id, e_inval);
5899         pii->has_overlap = true;
5900         ceph_decode_64_safe(&p, end, pii->overlap, e_inval);
5901 
5902         return 0;
5903 
5904 e_inval:
5905         return -EINVAL;
5906 }
5907 
5908 static int get_parent_info(struct rbd_device *rbd_dev,
5909                            struct parent_image_info *pii)
5910 {
5911         struct page *req_page, *reply_page;
5912         void *p;
5913         int ret;
5914 
5915         req_page = alloc_page(GFP_KERNEL);
5916         if (!req_page)
5917                 return -ENOMEM;
5918 
5919         reply_page = alloc_page(GFP_KERNEL);
5920         if (!reply_page) {
5921                 __free_page(req_page);
5922                 return -ENOMEM;
5923         }
5924 
5925         p = page_address(req_page);
5926         ceph_encode_64(&p, rbd_dev->spec->snap_id);
5927         ret = __get_parent_info(rbd_dev, req_page, reply_page, pii);
5928         if (ret > 0)
5929                 ret = __get_parent_info_legacy(rbd_dev, req_page, reply_page,
5930                                                pii);
5931 
5932         __free_page(req_page);
5933         __free_page(reply_page);
5934         return ret;
5935 }
5936 
5937 static int rbd_dev_v2_parent_info(struct rbd_device *rbd_dev)
5938 {
5939         struct rbd_spec *parent_spec;
5940         struct parent_image_info pii = { 0 };
5941         int ret;
5942 
5943         parent_spec = rbd_spec_alloc();
5944         if (!parent_spec)
5945                 return -ENOMEM;
5946 
5947         ret = get_parent_info(rbd_dev, &pii);
5948         if (ret)
5949                 goto out_err;
5950 
5951         dout("%s pool_id %llu pool_ns %s image_id %s snap_id %llu has_overlap %d overlap %llu\n",
5952              __func__, pii.pool_id, pii.pool_ns, pii.image_id, pii.snap_id,
5953              pii.has_overlap, pii.overlap);
5954 
5955         if (pii.pool_id == CEPH_NOPOOL || !pii.has_overlap) {
5956                 /*
5957                  * Either the parent never existed, or we have
5958                  * record of it but the image got flattened so it no
5959                  * longer has a parent.  When the parent of a
5960                  * layered image disappears we immediately set the
5961                  * overlap to 0.  The effect of this is that all new
5962                  * requests will be treated as if the image had no
5963                  * parent.
5964                  *
5965                  * If !pii.has_overlap, the parent image spec is not
5966                  * applicable.  It's there to avoid duplication in each
5967                  * snapshot record.
5968                  */
5969                 if (rbd_dev->parent_overlap) {
5970                         rbd_dev->parent_overlap = 0;
5971                         rbd_dev_parent_put(rbd_dev);
5972                         pr_info("%s: clone image has been flattened\n",
5973                                 rbd_dev->disk->disk_name);
5974                 }
5975 
5976                 goto out;       /* No parent?  No problem. */
5977         }
5978 
5979         /* The ceph file layout needs to fit pool id in 32 bits */
5980 
5981         ret = -EIO;
5982         if (pii.pool_id > (u64)U32_MAX) {
5983                 rbd_warn(NULL, "parent pool id too large (%llu > %u)",
5984                         (unsigned long long)pii.pool_id, U32_MAX);
5985                 goto out_err;
5986         }
5987 
5988         /*
5989          * The parent won't change (except when the clone is
5990          * flattened, already handled that).  So we only need to
5991          * record the parent spec we have not already done so.
5992          */
5993         if (!rbd_dev->parent_spec) {
5994                 parent_spec->pool_id = pii.pool_id;
5995                 if (pii.pool_ns && *pii.pool_ns) {
5996                         parent_spec->pool_ns = pii.pool_ns;
5997                         pii.pool_ns = NULL;
5998                 }
5999                 parent_spec->image_id = pii.image_id;
6000                 pii.image_id = NULL;
6001                 parent_spec->snap_id = pii.snap_id;
6002 
6003                 rbd_dev->parent_spec = parent_spec;
6004                 parent_spec = NULL;     /* rbd_dev now owns this */
6005         }
6006 
6007         /*
6008          * We always update the parent overlap.  If it's zero we issue
6009          * a warning, as we will proceed as if there was no parent.
6010          */
6011         if (!pii.overlap) {
6012                 if (parent_spec) {
6013                         /* refresh, careful to warn just once */
6014                         if (rbd_dev->parent_overlap)
6015                                 rbd_warn(rbd_dev,
6016                                     "clone now standalone (overlap became 0)");
6017                 } else {
6018                         /* initial probe */
6019                         rbd_warn(rbd_dev, "clone is standalone (overlap 0)");
6020                 }
6021         }
6022         rbd_dev->parent_overlap = pii.overlap;
6023 
6024 out:
6025         ret = 0;
6026 out_err:
6027         kfree(pii.pool_ns);
6028         kfree(pii.image_id);
6029         rbd_spec_put(parent_spec);
6030         return ret;
6031 }
6032 
6033 static int rbd_dev_v2_striping_info(struct rbd_device *rbd_dev)
6034 {
6035         struct {
6036                 __le64 stripe_unit;
6037                 __le64 stripe_count;
6038         } __attribute__ ((packed)) striping_info_buf = { 0 };
6039         size_t size = sizeof (striping_info_buf);
6040         void *p;
6041         int ret;
6042 
6043         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
6044                                 &rbd_dev->header_oloc, "get_stripe_unit_count",
6045                                 NULL, 0, &striping_info_buf, size);
6046         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
6047         if (ret < 0)
6048                 return ret;
6049         if (ret < size)
6050                 return -ERANGE;
6051 
6052         p = &striping_info_buf;
6053         rbd_dev->header.stripe_unit = ceph_decode_64(&p);
6054         rbd_dev->header.stripe_count = ceph_decode_64(&p);
6055         return 0;
6056 }
6057 
6058 static int rbd_dev_v2_data_pool(struct rbd_device *rbd_dev)
6059 {
6060         __le64 data_pool_id;
6061         int ret;
6062 
6063         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
6064                                   &rbd_dev->header_oloc, "get_data_pool",
6065                                   NULL, 0, &data_pool_id, sizeof(data_pool_id));
6066         if (ret < 0)
6067                 return ret;
6068         if (ret < sizeof(data_pool_id))
6069                 return -EBADMSG;
6070 
6071         rbd_dev->header.data_pool_id = le64_to_cpu(data_pool_id);
6072         WARN_ON(rbd_dev->header.data_pool_id == CEPH_NOPOOL);
6073         return 0;
6074 }
6075 
6076 static char *rbd_dev_image_name(struct rbd_device *rbd_dev)
6077 {
6078         CEPH_DEFINE_OID_ONSTACK(oid);
6079         size_t image_id_size;
6080         char *image_id;
6081         void *p;
6082         void *end;
6083         size_t size;
6084         void *reply_buf = NULL;
6085         size_t len = 0;
6086         char *image_name = NULL;
6087         int ret;
6088 
6089         rbd_assert(!rbd_dev->spec->image_name);
6090 
6091         len = strlen(rbd_dev->spec->image_id);
6092         image_id_size = sizeof (__le32) + len;
6093         image_id = kmalloc(image_id_size, GFP_KERNEL);
6094         if (!image_id)
6095                 return NULL;
6096 
6097         p = image_id;
6098         end = image_id + image_id_size;
6099         ceph_encode_string(&p, end, rbd_dev->spec->image_id, (u32)len);
6100 
6101         size = sizeof (__le32) + RBD_IMAGE_NAME_LEN_MAX;
6102         reply_buf = kmalloc(size, GFP_KERNEL);
6103         if (!reply_buf)
6104                 goto out;
6105 
6106         ceph_oid_printf(&oid, "%s", RBD_DIRECTORY);
6107         ret = rbd_obj_method_sync(rbd_dev, &oid, &rbd_dev->header_oloc,
6108                                   "dir_get_name", image_id, image_id_size,
6109                                   reply_buf, size);
6110         if (ret < 0)
6111                 goto out;
6112         p = reply_buf;
6113         end = reply_buf + ret;
6114 
6115         image_name = ceph_extract_encoded_string(&p, end, &len, GFP_KERNEL);
6116         if (IS_ERR(image_name))
6117                 image_name = NULL;
6118         else
6119                 dout("%s: name is %s len is %zd\n", __func__, image_name, len);
6120 out:
6121         kfree(reply_buf);
6122         kfree(image_id);
6123 
6124         return image_name;
6125 }
6126 
6127 static u64 rbd_v1_snap_id_by_name(struct rbd_device *rbd_dev, const char *name)
6128 {
6129         struct ceph_snap_context *snapc = rbd_dev->header.snapc;
6130         const char *snap_name;
6131         u32 which = 0;
6132 
6133         /* Skip over names until we find the one we are looking for */
6134 
6135         snap_name = rbd_dev->header.snap_names;
6136         while (which < snapc->num_snaps) {
6137                 if (!strcmp(name, snap_name))
6138                         return snapc->snaps[which];
6139                 snap_name += strlen(snap_name) + 1;
6140                 which++;
6141         }
6142         return CEPH_NOSNAP;
6143 }
6144 
6145 static u64 rbd_v2_snap_id_by_name(struct rbd_device *rbd_dev, const char *name)
6146 {
6147         struct ceph_snap_context *snapc = rbd_dev->header.snapc;
6148         u32 which;
6149         bool found = false;
6150         u64 snap_id;
6151 
6152         for (which = 0; !found && which < snapc->num_snaps; which++) {
6153                 const char *snap_name;
6154 
6155                 snap_id = snapc->snaps[which];
6156                 snap_name = rbd_dev_v2_snap_name(rbd_dev, snap_id);
6157                 if (IS_ERR(snap_name)) {
6158                         /* ignore no-longer existing snapshots */
6159                         if (PTR_ERR(snap_name) == -ENOENT)
6160                                 continue;
6161                         else
6162                                 break;
6163                 }
6164                 found = !strcmp(name, snap_name);
6165                 kfree(snap_name);
6166         }
6167         return found ? snap_id : CEPH_NOSNAP;
6168 }
6169 
6170 /*
6171  * Assumes name is never RBD_SNAP_HEAD_NAME; returns CEPH_NOSNAP if
6172  * no snapshot by that name is found, or if an error occurs.
6173  */
6174 static u64 rbd_snap_id_by_name(struct rbd_device *rbd_dev, const char *name)
6175 {
6176         if (rbd_dev->image_format == 1)
6177                 return rbd_v1_snap_id_by_name(rbd_dev, name);
6178 
6179         return rbd_v2_snap_id_by_name(rbd_dev, name);
6180 }
6181 
6182 /*
6183  * An image being mapped will have everything but the snap id.
6184  */
6185 static int rbd_spec_fill_snap_id(struct rbd_device *rbd_dev)
6186 {
6187         struct rbd_spec *spec = rbd_dev->spec;
6188 
6189         rbd_assert(spec->pool_id != CEPH_NOPOOL && spec->pool_name);
6190         rbd_assert(spec->image_id && spec->image_name);
6191         rbd_assert(spec->snap_name);
6192 
6193         if (strcmp(spec->snap_name, RBD_SNAP_HEAD_NAME)) {
6194                 u64 snap_id;
6195 
6196                 snap_id = rbd_snap_id_by_name(rbd_dev, spec->snap_name);
6197                 if (snap_id == CEPH_NOSNAP)
6198                         return -ENOENT;
6199 
6200                 spec->snap_id = snap_id;
6201         } else {
6202                 spec->snap_id = CEPH_NOSNAP;
6203         }
6204 
6205         return 0;
6206 }
6207 
6208 /*
6209  * A parent image will have all ids but none of the names.
6210  *
6211  * All names in an rbd spec are dynamically allocated.  It's OK if we
6212  * can't figure out the name for an image id.
6213  */
6214 static int rbd_spec_fill_names(struct rbd_device *rbd_dev)
6215 {
6216         struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
6217         struct rbd_spec *spec = rbd_dev->spec;
6218         const char *pool_name;
6219         const char *image_name;
6220         const char *snap_name;
6221         int ret;
6222 
6223         rbd_assert(spec->pool_id != CEPH_NOPOOL);
6224         rbd_assert(spec->image_id);
6225         rbd_assert(spec->snap_id != CEPH_NOSNAP);
6226 
6227         /* Get the pool name; we have to make our own copy of this */
6228 
6229         pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, spec->pool_id);
6230         if (!pool_name) {
6231                 rbd_warn(rbd_dev, "no pool with id %llu", spec->pool_id);
6232                 return -EIO;
6233         }
6234         pool_name = kstrdup(pool_name, GFP_KERNEL);
6235         if (!pool_name)
6236                 return -ENOMEM;
6237 
6238         /* Fetch the image name; tolerate failure here */
6239 
6240         image_name = rbd_dev_image_name(rbd_dev);
6241         if (!image_name)
6242                 rbd_warn(rbd_dev, "unable to get image name");
6243 
6244         /* Fetch the snapshot name */
6245 
6246         snap_name = rbd_snap_name(rbd_dev, spec->snap_id);
6247         if (IS_ERR(snap_name)) {
6248                 ret = PTR_ERR(snap_name);
6249                 goto out_err;
6250         }
6251 
6252         spec->pool_name = pool_name;
6253         spec->image_name = image_name;
6254         spec->snap_name = snap_name;
6255 
6256         return 0;
6257 
6258 out_err:
6259         kfree(image_name);
6260         kfree(pool_name);
6261         return ret;
6262 }
6263 
6264 static int rbd_dev_v2_snap_context(struct rbd_device *rbd_dev)
6265 {
6266         size_t size;
6267         int ret;
6268         void *reply_buf;
6269         void *p;
6270         void *end;
6271         u64 seq;
6272         u32 snap_count;
6273         struct ceph_snap_context *snapc;
6274         u32 i;
6275 
6276         /*
6277          * We'll need room for the seq value (maximum snapshot id),
6278          * snapshot count, and array of that many snapshot ids.
6279          * For now we have a fixed upper limit on the number we're
6280          * prepared to receive.
6281          */
6282         size = sizeof (__le64) + sizeof (__le32) +
6283                         RBD_MAX_SNAP_COUNT * sizeof (__le64);
6284         reply_buf = kzalloc(size, GFP_KERNEL);
6285         if (!reply_buf)
6286                 return -ENOMEM;
6287 
6288         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
6289                                   &rbd_dev->header_oloc, "get_snapcontext",
6290                                   NULL, 0, reply_buf, size);
6291         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
6292         if (ret < 0)
6293                 goto out;
6294 
6295         p = reply_buf;
6296         end = reply_buf + ret;
6297         ret = -ERANGE;
6298         ceph_decode_64_safe(&p, end, seq, out);
6299         ceph_decode_32_safe(&p, end, snap_count, out);
6300 
6301         /*
6302          * Make sure the reported number of snapshot ids wouldn't go
6303          * beyond the end of our buffer.  But before checking that,
6304          * make sure the computed size of the snapshot context we
6305          * allocate is representable in a size_t.
6306          */
6307         if (snap_count > (SIZE_MAX - sizeof (struct ceph_snap_context))
6308                                  / sizeof (u64)) {
6309                 ret = -EINVAL;
6310                 goto out;
6311         }
6312         if (!ceph_has_room(&p, end, snap_count * sizeof (__le64)))
6313                 goto out;
6314         ret = 0;
6315 
6316         snapc = ceph_create_snap_context(snap_count, GFP_KERNEL);
6317         if (!snapc) {
6318                 ret = -ENOMEM;
6319                 goto out;
6320         }
6321         snapc->seq = seq;
6322         for (i = 0; i < snap_count; i++)
6323                 snapc->snaps[i] = ceph_decode_64(&p);
6324 
6325         ceph_put_snap_context(rbd_dev->header.snapc);
6326         rbd_dev->header.snapc = snapc;
6327 
6328         dout("  snap context seq = %llu, snap_count = %u\n",
6329                 (unsigned long long)seq, (unsigned int)snap_count);
6330 out:
6331         kfree(reply_buf);
6332 
6333         return ret;
6334 }
6335 
6336 static const char *rbd_dev_v2_snap_name(struct rbd_device *rbd_dev,
6337                                         u64 snap_id)
6338 {
6339         size_t size;
6340         void *reply_buf;
6341         __le64 snapid;
6342         int ret;
6343         void *p;
6344         void *end;
6345         char *snap_name;
6346 
6347         size = sizeof (__le32) + RBD_MAX_SNAP_NAME_LEN;
6348         reply_buf = kmalloc(size, GFP_KERNEL);
6349         if (!reply_buf)
6350                 return ERR_PTR(-ENOMEM);
6351 
6352         snapid = cpu_to_le64(snap_id);
6353         ret = rbd_obj_method_sync(rbd_dev, &rbd_dev->header_oid,
6354                                   &rbd_dev->header_oloc, "get_snapshot_name",
6355                                   &snapid, sizeof(snapid), reply_buf, size);
6356         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
6357         if (ret < 0) {
6358                 snap_name = ERR_PTR(ret);
6359                 goto out;
6360         }
6361 
6362         p = reply_buf;
6363         end = reply_buf + ret;
6364         snap_name = ceph_extract_encoded_string(&p, end, NULL, GFP_KERNEL);
6365         if (IS_ERR(snap_name))
6366                 goto out;
6367 
6368         dout("  snap_id 0x%016llx snap_name = %s\n",
6369                 (unsigned long long)snap_id, snap_name);
6370 out:
6371         kfree(reply_buf);
6372 
6373         return snap_name;
6374 }
6375 
6376 static int rbd_dev_v2_header_info(struct rbd_device *rbd_dev)
6377 {
6378         bool first_time = rbd_dev->header.object_prefix == NULL;
6379         int ret;
6380 
6381         ret = rbd_dev_v2_image_size(rbd_dev);
6382         if (ret)
6383                 return ret;
6384 
6385         if (first_time) {
6386                 ret = rbd_dev_v2_header_onetime(rbd_dev);
6387                 if (ret)
6388                         return ret;
6389         }
6390 
6391         ret = rbd_dev_v2_snap_context(rbd_dev);
6392         if (ret && first_time) {
6393                 kfree(rbd_dev->header.object_prefix);
6394                 rbd_dev->header.object_prefix = NULL;
6395         }
6396 
6397         return ret;
6398 }
6399 
6400 static int rbd_dev_header_info(struct rbd_device *rbd_dev)
6401 {
6402         rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
6403 
6404         if (rbd_dev->image_format == 1)
6405                 return rbd_dev_v1_header_info(rbd_dev);
6406 
6407         return rbd_dev_v2_header_info(rbd_dev);
6408 }
6409 
6410 /*
6411  * Skips over white space at *buf, and updates *buf to point to the
6412  * first found non-space character (if any). Returns the length of
6413  * the token (string of non-white space characters) found.  Note
6414  * that *buf must be terminated with '\0'.
6415  */
6416 static inline size_t next_token(const char **buf)
6417 {
6418         /*
6419         * These are the characters that produce nonzero for
6420         * isspace() in the "C" and "POSIX" locales.
6421         */
6422         const char *spaces = " \f\n\r\t\v";
6423 
6424         *buf += strspn(*buf, spaces);   /* Find start of token */
6425 
6426         return strcspn(*buf, spaces);   /* Return token length */
6427 }
6428 
6429 /*
6430  * Finds the next token in *buf, dynamically allocates a buffer big
6431  * enough to hold a copy of it, and copies the token into the new
6432  * buffer.  The copy is guaranteed to be terminated with '\0'.  Note
6433  * that a duplicate buffer is created even for a zero-length token.
6434  *
6435  * Returns a pointer to the newly-allocated duplicate, or a null
6436  * pointer if memory for the duplicate was not available.  If
6437  * the lenp argument is a non-null pointer, the length of the token
6438  * (not including the '\0') is returned in *lenp.
6439  *
6440  * If successful, the *buf pointer will be updated to point beyond
6441  * the end of the found token.
6442  *
6443  * Note: uses GFP_KERNEL for allocation.
6444  */
6445 static inline char *dup_token(const char **buf, size_t *lenp)
6446 {
6447         char *dup;
6448         size_t len;
6449 
6450         len = next_token(buf);
6451         dup = kmemdup(*buf, len + 1, GFP_KERNEL);
6452         if (!dup)
6453                 return NULL;
6454         *(dup + len) = '\0';
6455         *buf += len;
6456 
6457         if (lenp)
6458                 *lenp = len;
6459 
6460         return dup;
6461 }
6462 
6463 /*
6464  * Parse the options provided for an "rbd add" (i.e., rbd image
6465  * mapping) request.  These arrive via a write to /sys/bus/rbd/add,
6466  * and the data written is passed here via a NUL-terminated buffer.
6467  * Returns 0 if successful or an error code otherwise.
6468  *
6469  * The information extracted from these options is recorded in
6470  * the other parameters which return dynamically-allocated
6471  * structures:
6472  *  ceph_opts
6473  *      The address of a pointer that will refer to a ceph options
6474  *      structure.  Caller must release the returned pointer using
6475  *      ceph_destroy_options() when it is no longer needed.
6476  *  rbd_opts
6477  *      Address of an rbd options pointer.  Fully initialized by
6478  *      this function; caller must release with kfree().
6479  *  spec
6480  *      Address of an rbd image specification pointer.  Fully
6481  *      initialized by this function based on parsed options.
6482  *      Caller must release with rbd_spec_put().
6483  *
6484  * The options passed take this form:
6485  *  <mon_addrs> <options> <pool_name> <image_name> [<snap_id>]
6486  * where:
6487  *  <mon_addrs>
6488  *      A comma-separated list of one or more monitor addresses.
6489  *      A monitor address is an ip address, optionally followed
6490  *      by a port number (separated by a colon).
6491  *        I.e.:  ip1[:port1][,ip2[:port2]...]
6492  *  <options>
6493  *      A comma-separated list of ceph and/or rbd options.
6494  *  <pool_name>
6495  *      The name of the rados pool containing the rbd image.
6496  *  <image_name>
6497  *      The name of the image in that pool to map.
6498  *  <snap_id>
6499  *      An optional snapshot id.  If provided, the mapping will
6500  *      present data from the image at the time that snapshot was
6501  *      created.  The image head is used if no snapshot id is
6502  *      provided.  Snapshot mappings are always read-only.
6503  */
6504 static int rbd_add_parse_args(const char *buf,
6505                                 struct ceph_options **ceph_opts,
6506                                 struct rbd_options **opts,
6507                                 struct rbd_spec **rbd_spec)
6508 {
6509         size_t len;
6510         char *options;
6511         const char *mon_addrs;
6512         char *snap_name;
6513         size_t mon_addrs_size;
6514         struct parse_rbd_opts_ctx pctx = { 0 };
6515         struct ceph_options *copts;
6516         int ret;
6517 
6518         /* The first four tokens are required */
6519 
6520         len = next_token(&buf);
6521         if (!len) {
6522                 rbd_warn(NULL, "no monitor address(es) provided");
6523                 return -EINVAL;
6524         }
6525         mon_addrs = buf;
6526         mon_addrs_size = len + 1;
6527         buf += len;
6528 
6529         ret = -EINVAL;
6530         options = dup_token(&buf, NULL);
6531         if (!options)
6532                 return -ENOMEM;
6533         if (!*options) {
6534                 rbd_warn(NULL, "no options provided");
6535                 goto out_err;
6536         }
6537 
6538         pctx.spec = rbd_spec_alloc();
6539         if (!pctx.spec)
6540                 goto out_mem;
6541 
6542         pctx.spec->pool_name = dup_token(&buf, NULL);
6543         if (!pctx.spec->pool_name)
6544                 goto out_mem;
6545         if (!*pctx.spec->pool_name) {
6546                 rbd_warn(NULL, "no pool name provided");
6547                 goto out_err;
6548         }
6549 
6550         pctx.spec->image_name = dup_token(&buf, NULL);
6551         if (!pctx.spec->image_name)
6552                 goto out_mem;
6553         if (!*pctx.spec->image_name) {
6554                 rbd_warn(NULL, "no image name provided");
6555                 goto out_err;
6556         }
6557 
6558         /*
6559          * Snapshot name is optional; default is to use "-"
6560          * (indicating the head/no snapshot).
6561          */
6562         len = next_token(&buf);
6563         if (!len) {
6564                 buf = RBD_SNAP_HEAD_NAME; /* No snapshot supplied */
6565                 len = sizeof (RBD_SNAP_HEAD_NAME) - 1;
6566         } else if (len > RBD_MAX_SNAP_NAME_LEN) {
6567                 ret = -ENAMETOOLONG;
6568                 goto out_err;
6569         }
6570         snap_name = kmemdup(buf, len + 1, GFP_KERNEL);
6571         if (!snap_name)
6572                 goto out_mem;
6573         *(snap_name + len) = '\0';
6574         pctx.spec->snap_name = snap_name;
6575 
6576         /* Initialize all rbd options to the defaults */
6577 
6578         pctx.opts = kzalloc(sizeof(*pctx.opts), GFP_KERNEL);
6579         if (!pctx.opts)
6580                 goto out_mem;
6581 
6582         pctx.opts->read_only = RBD_READ_ONLY_DEFAULT;
6583         pctx.opts->queue_depth = RBD_QUEUE_DEPTH_DEFAULT;
6584         pctx.opts->alloc_size = RBD_ALLOC_SIZE_DEFAULT;
6585         pctx.opts->lock_timeout = RBD_LOCK_TIMEOUT_DEFAULT;
6586         pctx.opts->lock_on_read = RBD_LOCK_ON_READ_DEFAULT;
6587         pctx.opts->exclusive = RBD_EXCLUSIVE_DEFAULT;
6588         pctx.opts->trim = RBD_TRIM_DEFAULT;
6589 
6590         copts = ceph_parse_options(options, mon_addrs,
6591                                    mon_addrs + mon_addrs_size - 1,
6592                                    parse_rbd_opts_token, &pctx);
6593         if (IS_ERR(copts)) {
6594                 ret = PTR_ERR(copts);
6595                 goto out_err;
6596         }
6597         kfree(options);
6598 
6599         *ceph_opts = copts;
6600         *opts = pctx.opts;
6601         *rbd_spec = pctx.spec;
6602 
6603         return 0;
6604 out_mem:
6605         ret = -ENOMEM;
6606 out_err:
6607         kfree(pctx.opts);
6608         rbd_spec_put(pctx.spec);
6609         kfree(options);
6610 
6611         return ret;
6612 }
6613 
6614 static void rbd_dev_image_unlock(struct rbd_device *rbd_dev)
6615 {
6616         down_write(&rbd_dev->lock_rwsem);
6617         if (__rbd_is_lock_owner(rbd_dev))
6618                 __rbd_release_lock(rbd_dev);
6619         up_write(&rbd_dev->lock_rwsem);
6620 }
6621 
6622 /*
6623  * If the wait is interrupted, an error is returned even if the lock
6624  * was successfully acquired.  rbd_dev_image_unlock() will release it
6625  * if needed.
6626  */
6627 static int rbd_add_acquire_lock(struct rbd_device *rbd_dev)
6628 {
6629         long ret;
6630 
6631         if (!(rbd_dev->header.features & RBD_FEATURE_EXCLUSIVE_LOCK)) {
6632                 if (!rbd_dev->opts->exclusive && !rbd_dev->opts->lock_on_read)
6633                         return 0;
6634 
6635                 rbd_warn(rbd_dev, "exclusive-lock feature is not enabled");
6636                 return -EINVAL;
6637         }
6638 
6639         if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
6640                 return 0;
6641 
6642         rbd_assert(!rbd_is_lock_owner(rbd_dev));
6643         queue_delayed_work(rbd_dev->task_wq, &rbd_dev->lock_dwork, 0);
6644         ret = wait_for_completion_killable_timeout(&rbd_dev->acquire_wait,
6645                             ceph_timeout_jiffies(rbd_dev->opts->lock_timeout));
6646         if (ret > 0) {
6647                 ret = rbd_dev->acquire_err;
6648         } else {
6649                 cancel_delayed_work_sync(&rbd_dev->lock_dwork);
6650                 if (!ret)
6651                         ret = -ETIMEDOUT;
6652         }
6653 
6654         if (ret) {
6655                 rbd_warn(rbd_dev, "failed to acquire exclusive lock: %ld", ret);
6656                 return ret;
6657         }
6658 
6659         /*
6660          * The lock may have been released by now, unless automatic lock
6661          * transitions are disabled.
6662          */
6663         rbd_assert(!rbd_dev->opts->exclusive || rbd_is_lock_owner(rbd_dev));
6664         return 0;
6665 }
6666 
6667 /*
6668  * An rbd format 2 image has a unique identifier, distinct from the
6669  * name given to it by the user.  Internally, that identifier is
6670  * what's used to specify the names of objects related to the image.
6671  *
6672  * A special "rbd id" object is used to map an rbd image name to its
6673  * id.  If that object doesn't exist, then there is no v2 rbd image
6674  * with the supplied name.
6675  *
6676  * This function will record the given rbd_dev's image_id field if
6677  * it can be determined, and in that case will return 0.  If any
6678  * errors occur a negative errno will be returned and the rbd_dev's
6679  * image_id field will be unchanged (and should be NULL).
6680  */
6681 static int rbd_dev_image_id(struct rbd_device *rbd_dev)
6682 {
6683         int ret;
6684         size_t size;
6685         CEPH_DEFINE_OID_ONSTACK(oid);
6686         void *response;
6687         char *image_id;
6688 
6689         /*
6690          * When probing a parent image, the image id is already
6691          * known (and the image name likely is not).  There's no
6692          * need to fetch the image id again in this case.  We
6693          * do still need to set the image format though.
6694          */
6695         if (rbd_dev->spec->image_id) {
6696                 rbd_dev->image_format = *rbd_dev->spec->image_id ? 2 : 1;
6697 
6698                 return 0;
6699         }
6700 
6701         /*
6702          * First, see if the format 2 image id file exists, and if
6703          * so, get the image's persistent id from it.
6704          */
6705         ret = ceph_oid_aprintf(&oid, GFP_KERNEL, "%s%s", RBD_ID_PREFIX,
6706                                rbd_dev->spec->image_name);
6707         if (ret)
6708                 return ret;
6709 
6710         dout("rbd id object name is %s\n", oid.name);
6711 
6712         /* Response will be an encoded string, which includes a length */
6713         size = sizeof (__le32) + RBD_IMAGE_ID_LEN_MAX;
6714         response = kzalloc(size, GFP_NOIO);
6715         if (!response) {
6716                 ret = -ENOMEM;
6717                 goto out;
6718         }
6719 
6720         /* If it doesn't exist we'll assume it's a format 1 image */
6721 
6722         ret = rbd_obj_method_sync(rbd_dev, &oid, &rbd_dev->header_oloc,
6723                                   "get_id", NULL, 0,
6724                                   response, size);
6725         dout("%s: rbd_obj_method_sync returned %d\n", __func__, ret);
6726         if (ret == -ENOENT) {
6727                 image_id = kstrdup("", GFP_KERNEL);
6728                 ret = image_id ? 0 : -ENOMEM;
6729                 if (!ret)
6730                         rbd_dev->image_format = 1;
6731         } else if (ret >= 0) {
6732                 void *p = response;
6733 
6734                 image_id = ceph_extract_encoded_string(&p, p + ret,
6735                                                 NULL, GFP_NOIO);
6736                 ret = PTR_ERR_OR_ZERO(image_id);
6737                 if (!ret)
6738                         rbd_dev->image_format = 2;
6739         }
6740 
6741         if (!ret) {
6742                 rbd_dev->spec->image_id = image_id;
6743                 dout("image_id is %s\n", image_id);
6744         }
6745 out:
6746         kfree(response);
6747         ceph_oid_destroy(&oid);
6748         return ret;
6749 }
6750 
6751 /*
6752  * Undo whatever state changes are made by v1 or v2 header info
6753  * call.
6754  */
6755 static void rbd_dev_unprobe(struct rbd_device *rbd_dev)
6756 {
6757         struct rbd_image_header *header;
6758 
6759         rbd_dev_parent_put(rbd_dev);
6760         rbd_object_map_free(rbd_dev);
6761         rbd_dev_mapping_clear(rbd_dev);
6762 
6763         /* Free dynamic fields from the header, then zero it out */
6764 
6765         header = &rbd_dev->header;
6766         ceph_put_snap_context(header->snapc);
6767         kfree(header->snap_sizes);
6768         kfree(header->snap_names);
6769         kfree(header->object_prefix);
6770         memset(header, 0, sizeof (*header));
6771 }
6772 
6773 static int rbd_dev_v2_header_onetime(struct rbd_device *rbd_dev)
6774 {
6775         int ret;
6776 
6777         ret = rbd_dev_v2_object_prefix(rbd_dev);
6778         if (ret)
6779                 goto out_err;
6780 
6781         /*
6782          * Get the and check features for the image.  Currently the
6783          * features are assumed to never change.
6784          */
6785         ret = rbd_dev_v2_features(rbd_dev);
6786         if (ret)
6787                 goto out_err;
6788 
6789         /* If the image supports fancy striping, get its parameters */
6790 
6791         if (rbd_dev->header.features & RBD_FEATURE_STRIPINGV2) {
6792                 ret = rbd_dev_v2_striping_info(rbd_dev);
6793                 if (ret < 0)
6794                         goto out_err;
6795         }
6796 
6797         if (rbd_dev->header.features & RBD_FEATURE_DATA_POOL) {
6798                 ret = rbd_dev_v2_data_pool(rbd_dev);
6799                 if (ret)
6800                         goto out_err;
6801         }
6802 
6803         rbd_init_layout(rbd_dev);
6804         return 0;
6805 
6806 out_err:
6807         rbd_dev->header.features = 0;
6808         kfree(rbd_dev->header.object_prefix);
6809         rbd_dev->header.object_prefix = NULL;
6810         return ret;
6811 }
6812 
6813 /*
6814  * @depth is rbd_dev_image_probe() -> rbd_dev_probe_parent() ->
6815  * rbd_dev_image_probe() recursion depth, which means it's also the
6816  * length of the already discovered part of the parent chain.
6817  */
6818 static int rbd_dev_probe_parent(struct rbd_device *rbd_dev, int depth)
6819 {
6820         struct rbd_device *parent = NULL;
6821         int ret;
6822 
6823         if (!rbd_dev->parent_spec)
6824                 return 0;
6825 
6826         if (++depth > RBD_MAX_PARENT_CHAIN_LEN) {
6827                 pr_info("parent chain is too long (%d)\n", depth);
6828                 ret = -EINVAL;
6829                 goto out_err;
6830         }
6831 
6832         parent = __rbd_dev_create(rbd_dev->rbd_client, rbd_dev->parent_spec);
6833         if (!parent) {
6834                 ret = -ENOMEM;
6835                 goto out_err;
6836         }
6837 
6838         /*
6839          * Images related by parent/child relationships always share
6840          * rbd_client and spec/parent_spec, so bump their refcounts.
6841          */
6842         __rbd_get_client(rbd_dev->rbd_client);
6843         rbd_spec_get(rbd_dev->parent_spec);
6844 
6845         ret = rbd_dev_image_probe(parent, depth);
6846         if (ret < 0)
6847                 goto out_err;
6848 
6849         rbd_dev->parent = parent;
6850         atomic_set(&rbd_dev->parent_ref, 1);
6851         return 0;
6852 
6853 out_err:
6854         rbd_dev_unparent(rbd_dev);
6855         rbd_dev_destroy(parent);
6856         return ret;
6857 }
6858 
6859 static void rbd_dev_device_release(struct rbd_device *rbd_dev)
6860 {
6861         clear_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags);
6862         rbd_free_disk(rbd_dev);
6863         if (!single_major)
6864                 unregister_blkdev(rbd_dev->major, rbd_dev->name);
6865 }
6866 
6867 /*
6868  * rbd_dev->header_rwsem must be locked for write and will be unlocked
6869  * upon return.
6870  */
6871 static int rbd_dev_device_setup(struct rbd_device *rbd_dev)
6872 {
6873         int ret;
6874 
6875         /* Record our major and minor device numbers. */
6876 
6877         if (!single_major) {
6878                 ret = register_blkdev(0, rbd_dev->name);
6879                 if (ret < 0)
6880                         goto err_out_unlock;
6881 
6882                 rbd_dev->major = ret;
6883                 rbd_dev->minor = 0;
6884         } else {
6885                 rbd_dev->major = rbd_major;
6886                 rbd_dev->minor = rbd_dev_id_to_minor(rbd_dev->dev_id);
6887         }
6888 
6889         /* Set up the blkdev mapping. */
6890 
6891         ret = rbd_init_disk(rbd_dev);
6892         if (ret)
6893                 goto err_out_blkdev;
6894 
6895         set_capacity(rbd_dev->disk, rbd_dev->mapping.size / SECTOR_SIZE);
6896         set_disk_ro(rbd_dev->disk, rbd_dev->opts->read_only);
6897 
6898         ret = dev_set_name(&rbd_dev->dev, "%d", rbd_dev->dev_id);
6899         if (ret)
6900                 goto err_out_disk;
6901 
6902         set_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags);
6903         up_write(&rbd_dev->header_rwsem);
6904         return 0;
6905 
6906 err_out_disk:
6907         rbd_free_disk(rbd_dev);
6908 err_out_blkdev:
6909         if (!single_major)
6910                 unregister_blkdev(rbd_dev->major, rbd_dev->name);
6911 err_out_unlock:
6912         up_write(&rbd_dev->header_rwsem);
6913         return ret;
6914 }
6915 
6916 static int rbd_dev_header_name(struct rbd_device *rbd_dev)
6917 {
6918         struct rbd_spec *spec = rbd_dev->spec;
6919         int ret;
6920 
6921         /* Record the header object name for this rbd image. */
6922 
6923         rbd_assert(rbd_image_format_valid(rbd_dev->image_format));
6924         if (rbd_dev->image_format == 1)
6925                 ret = ceph_oid_aprintf(&rbd_dev->header_oid, GFP_KERNEL, "%s%s",
6926                                        spec->image_name, RBD_SUFFIX);
6927         else
6928                 ret = ceph_oid_aprintf(&rbd_dev->header_oid, GFP_KERNEL, "%s%s",
6929                                        RBD_HEADER_PREFIX, spec->image_id);
6930 
6931         return ret;
6932 }
6933 
6934 static void rbd_dev_image_release(struct rbd_device *rbd_dev)
6935 {
6936         if (rbd_dev->opts)
6937                 rbd_unregister_watch(rbd_dev);
6938 
6939         rbd_dev_unprobe(rbd_dev);
6940         rbd_dev->image_format = 0;
6941         kfree(rbd_dev->spec->image_id);
6942         rbd_dev->spec->image_id = NULL;
6943 }
6944 
6945 /*
6946  * Probe for the existence of the header object for the given rbd
6947  * device.  If this image is the one being mapped (i.e., not a
6948  * parent), initiate a watch on its header object before using that
6949  * object to get detailed information about the rbd image.
6950  *
6951  * On success, returns with header_rwsem held for write if called
6952  * with @depth == 0.
6953  */
6954 static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
6955 {
6956         int ret;
6957 
6958         /*
6959          * Get the id from the image id object.  Unless there's an
6960          * error, rbd_dev->spec->image_id will be filled in with
6961          * a dynamically-allocated string, and rbd_dev->image_format
6962          * will be set to either 1 or 2.
6963          */
6964         ret = rbd_dev_image_id(rbd_dev);
6965         if (ret)
6966                 return ret;
6967 
6968         ret = rbd_dev_header_name(rbd_dev);
6969         if (ret)
6970                 goto err_out_format;
6971 
6972         if (!depth) {
6973                 ret = rbd_register_watch(rbd_dev);
6974                 if (ret) {
6975                         if (ret == -ENOENT)
6976                                 pr_info("image %s/%s%s%s does not exist\n",
6977                                         rbd_dev->spec->pool_name,
6978                                         rbd_dev->spec->pool_ns ?: "",
6979                                         rbd_dev->spec->pool_ns ? "/" : "",
6980                                         rbd_dev->spec->image_name);
6981                         goto err_out_format;
6982                 }
6983         }
6984 
6985         if (!depth)
6986                 down_write(&rbd_dev->header_rwsem);
6987 
6988         ret = rbd_dev_header_info(rbd_dev);
6989         if (ret)
6990                 goto err_out_probe;
6991 
6992         /*
6993          * If this image is the one being mapped, we have pool name and
6994          * id, image name and id, and snap name - need to fill snap id.
6995          * Otherwise this is a parent image, identified by pool, image
6996          * and snap ids - need to fill in names for those ids.
6997          */
6998         if (!depth)
6999                 ret = rbd_spec_fill_snap_id(rbd_dev);
7000         else
7001                 ret = rbd_spec_fill_names(rbd_dev);
7002         if (ret) {
7003                 if (ret == -ENOENT)
7004                         pr_info("snap %s/%s%s%s@%s does not exist\n",
7005                                 rbd_dev->spec->pool_name,
7006                                 rbd_dev->spec->pool_ns ?: "",
7007                                 rbd_dev->spec->pool_ns ? "/" : "",
7008                                 rbd_dev->spec->image_name,
7009                                 rbd_dev->spec->snap_name);
7010                 goto err_out_probe;
7011         }
7012 
7013         ret = rbd_dev_mapping_set(rbd_dev);
7014         if (ret)
7015                 goto err_out_probe;
7016 
7017         if (rbd_dev->spec->snap_id != CEPH_NOSNAP &&
7018             (rbd_dev->header.features & RBD_FEATURE_OBJECT_MAP)) {
7019                 ret = rbd_object_map_load(rbd_dev);
7020                 if (ret)
7021                         goto err_out_probe;
7022         }
7023 
7024         if (rbd_dev->header.features & RBD_FEATURE_LAYERING) {
7025                 ret = rbd_dev_v2_parent_info(rbd_dev);
7026                 if (ret)
7027                         goto err_out_probe;
7028         }
7029 
7030         ret = rbd_dev_probe_parent(rbd_dev, depth);
7031         if (ret)
7032                 goto err_out_probe;
7033 
7034         dout("discovered format %u image, header name is %s\n",
7035                 rbd_dev->image_format, rbd_dev->header_oid.name);
7036         return 0;
7037 
7038 err_out_probe:
7039         if (!depth)
7040                 up_write(&rbd_dev->header_rwsem);
7041         if (!depth)
7042                 rbd_unregister_watch(rbd_dev);
7043         rbd_dev_unprobe(rbd_dev);
7044 err_out_format:
7045         rbd_dev->image_format = 0;
7046         kfree(rbd_dev->spec->image_id);
7047         rbd_dev->spec->image_id = NULL;
7048         return ret;
7049 }
7050 
7051 static ssize_t do_rbd_add(struct bus_type *bus,
7052                           const char *buf,
7053                           size_t count)
7054 {
7055         struct rbd_device *rbd_dev = NULL;
7056         struct ceph_options *ceph_opts = NULL;
7057         struct rbd_options *rbd_opts = NULL;
7058         struct rbd_spec *spec = NULL;
7059         struct rbd_client *rbdc;
7060         int rc;
7061 
7062         if (!try_module_get(THIS_MODULE))
7063                 return -ENODEV;
7064 
7065         /* parse add command */
7066         rc = rbd_add_parse_args(buf, &ceph_opts, &rbd_opts, &spec);
7067         if (rc < 0)
7068                 goto out;
7069 
7070         rbdc = rbd_get_client(ceph_opts);
7071         if (IS_ERR(rbdc)) {
7072                 rc = PTR_ERR(rbdc);
7073                 goto err_out_args;
7074         }
7075 
7076         /* pick the pool */
7077         rc = ceph_pg_poolid_by_name(rbdc->client->osdc.osdmap, spec->pool_name);
7078         if (rc < 0) {
7079                 if (rc == -ENOENT)
7080                         pr_info("pool %s does not exist\n", spec->pool_name);
7081                 goto err_out_client;
7082         }
7083         spec->pool_id = (u64)rc;
7084 
7085         rbd_dev = rbd_dev_create(rbdc, spec, rbd_opts);
7086         if (!rbd_dev) {
7087                 rc = -ENOMEM;
7088                 goto err_out_client;
7089         }
7090         rbdc = NULL;            /* rbd_dev now owns this */
7091         spec = NULL;            /* rbd_dev now owns this */
7092         rbd_opts = NULL;        /* rbd_dev now owns this */
7093 
7094         rbd_dev->config_info = kstrdup(buf, GFP_KERNEL);
7095         if (!rbd_dev->config_info) {
7096                 rc = -ENOMEM;
7097                 goto err_out_rbd_dev;
7098         }
7099 
7100         rc = rbd_dev_image_probe(rbd_dev, 0);
7101         if (rc < 0)
7102                 goto err_out_rbd_dev;
7103 
7104         /* If we are mapping a snapshot it must be marked read-only */
7105         if (rbd_dev->spec->snap_id != CEPH_NOSNAP)
7106                 rbd_dev->opts->read_only = true;
7107 
7108         if (rbd_dev->opts->alloc_size > rbd_dev->layout.object_size) {
7109                 rbd_warn(rbd_dev, "alloc_size adjusted to %u",
7110                          rbd_dev->layout.object_size);
7111                 rbd_dev->opts->alloc_size = rbd_dev->layout.object_size;
7112         }
7113 
7114         rc = rbd_dev_device_setup(rbd_dev);
7115         if (rc)
7116                 goto err_out_image_probe;
7117 
7118         rc = rbd_add_acquire_lock(rbd_dev);
7119         if (rc)
7120                 goto err_out_image_lock;
7121 
7122         /* Everything's ready.  Announce the disk to the world. */
7123 
7124         rc = device_add(&rbd_dev->dev);
7125         if (rc)
7126                 goto err_out_image_lock;
7127 
7128         add_disk(rbd_dev->disk);
7129         /* see rbd_init_disk() */
7130         blk_put_queue(rbd_dev->disk->queue);
7131 
7132         spin_lock(&rbd_dev_list_lock);
7133         list_add_tail(&rbd_dev->node, &rbd_dev_list);
7134         spin_unlock(&rbd_dev_list_lock);
7135 
7136         pr_info("%s: capacity %llu features 0x%llx\n", rbd_dev->disk->disk_name,
7137                 (unsigned long long)get_capacity(rbd_dev->disk) << SECTOR_SHIFT,
7138                 rbd_dev->header.features);
7139         rc = count;
7140 out:
7141         module_put(THIS_MODULE);
7142         return rc;
7143 
7144 err_out_image_lock:
7145         rbd_dev_image_unlock(rbd_dev);
7146         rbd_dev_device_release(rbd_dev);
7147 err_out_image_probe:
7148         rbd_dev_image_release(rbd_dev);
7149 err_out_rbd_dev:
7150         rbd_dev_destroy(rbd_dev);
7151 err_out_client:
7152         rbd_put_client(rbdc);
7153 err_out_args:
7154         rbd_spec_put(spec);
7155         kfree(rbd_opts);
7156         goto out;
7157 }
7158 
7159 static ssize_t add_store(struct bus_type *bus, const char *buf, size_t count)
7160 {
7161         if (single_major)
7162                 return -EINVAL;
7163 
7164         return do_rbd_add(bus, buf, count);
7165 }
7166 
7167 static ssize_t add_single_major_store(struct bus_type *bus, const char *buf,
7168                                       size_t count)
7169 {
7170         return do_rbd_add(bus, buf, count);
7171 }
7172 
7173 static void rbd_dev_remove_parent(struct rbd_device *rbd_dev)
7174 {
7175         while (rbd_dev->parent) {
7176                 struct rbd_device *first = rbd_dev;
7177                 struct rbd_device *second = first->parent;
7178                 struct rbd_device *third;
7179 
7180                 /*
7181                  * Follow to the parent with no grandparent and
7182                  * remove it.
7183                  */
7184                 while (second && (third = second->parent)) {
7185                         first = second;
7186                         second = third;
7187                 }
7188                 rbd_assert(second);
7189                 rbd_dev_image_release(second);
7190                 rbd_dev_destroy(second);
7191                 first->parent = NULL;
7192                 first->parent_overlap = 0;
7193 
7194                 rbd_assert(first->parent_spec);
7195                 rbd_spec_put(first->parent_spec);
7196                 first->parent_spec = NULL;
7197         }
7198 }
7199 
7200 static ssize_t do_rbd_remove(struct bus_type *bus,
7201                              const char *buf,
7202                              size_t count)
7203 {
7204         struct rbd_device *rbd_dev = NULL;
7205         struct list_head *tmp;
7206         int dev_id;
7207         char opt_buf[6];
7208         bool force = false;
7209         int ret;
7210 
7211         dev_id = -1;
7212         opt_buf[0] = '\0';
7213         sscanf(buf, "%d %5s", &dev_id, opt_buf);
7214         if (dev_id < 0) {
7215                 pr_err("dev_id out of range\n");
7216                 return -EINVAL;
7217         }
7218         if (opt_buf[0] != '\0') {
7219                 if (!strcmp(opt_buf, "force")) {
7220                         force = true;
7221                 } else {
7222                         pr_err("bad remove option at '%s'\n", opt_buf);
7223                         return -EINVAL;
7224                 }
7225         }
7226 
7227         ret = -ENOENT;
7228         spin_lock(&rbd_dev_list_lock);
7229         list_for_each(tmp, &rbd_dev_list) {
7230                 rbd_dev = list_entry(tmp, struct rbd_device, node);
7231                 if (rbd_dev->dev_id == dev_id) {
7232                         ret = 0;
7233                         break;
7234                 }
7235         }
7236         if (!ret) {
7237                 spin_lock_irq(&rbd_dev->lock);
7238                 if (rbd_dev->open_count && !force)
7239                         ret = -EBUSY;
7240                 else if (test_and_set_bit(RBD_DEV_FLAG_REMOVING,
7241                                           &rbd_dev->flags))
7242                         ret = -EINPROGRESS;
7243                 spin_unlock_irq(&rbd_dev->lock);
7244         }
7245         spin_unlock(&rbd_dev_list_lock);
7246         if (ret)
7247                 return ret;
7248 
7249         if (force) {
7250                 /*
7251                  * Prevent new IO from being queued and wait for existing
7252                  * IO to complete/fail.
7253                  */
7254                 blk_mq_freeze_queue(rbd_dev->disk->queue);
7255                 blk_set_queue_dying(rbd_dev->disk->queue);
7256         }
7257 
7258         del_gendisk(rbd_dev->disk);
7259         spin_lock(&rbd_dev_list_lock);
7260         list_del_init(&rbd_dev->node);
7261         spin_unlock(&rbd_dev_list_lock);
7262         device_del(&rbd_dev->dev);
7263 
7264         rbd_dev_image_unlock(rbd_dev);
7265         rbd_dev_device_release(rbd_dev);
7266         rbd_dev_image_release(rbd_dev);
7267         rbd_dev_destroy(rbd_dev);
7268         return count;
7269 }
7270 
7271 static ssize_t remove_store(struct bus_type *bus, const char *buf, size_t count)
7272 {
7273         if (single_major)
7274                 return -EINVAL;
7275 
7276         return do_rbd_remove(bus, buf, count);
7277 }
7278 
7279 static ssize_t remove_single_major_store(struct bus_type *bus, const char *buf,
7280                                          size_t count)
7281 {
7282         return do_rbd_remove(bus, buf, count);
7283 }
7284 
7285 /*
7286  * create control files in sysfs
7287  * /sys/bus/rbd/...
7288  */
7289 static int __init rbd_sysfs_init(void)
7290 {
7291         int ret;
7292 
7293         ret = device_register(&rbd_root_dev);
7294         if (ret < 0)
7295                 return ret;
7296 
7297         ret = bus_register(&rbd_bus_type);
7298         if (ret < 0)
7299                 device_unregister(&rbd_root_dev);
7300 
7301         return ret;
7302 }
7303 
7304 static void __exit rbd_sysfs_cleanup(void)
7305 {
7306         bus_unregister(&rbd_bus_type);
7307         device_unregister(&rbd_root_dev);
7308 }
7309 
7310 static int __init rbd_slab_init(void)
7311 {
7312         rbd_assert(!rbd_img_request_cache);
7313         rbd_img_request_cache = KMEM_CACHE(rbd_img_request, 0);
7314         if (!rbd_img_request_cache)
7315                 return -ENOMEM;
7316 
7317         rbd_assert(!rbd_obj_request_cache);
7318         rbd_obj_request_cache = KMEM_CACHE(rbd_obj_request, 0);
7319         if (!rbd_obj_request_cache)
7320                 goto out_err;
7321 
7322         return 0;
7323 
7324 out_err:
7325         kmem_cache_destroy(rbd_img_request_cache);
7326         rbd_img_request_cache = NULL;
7327         return -ENOMEM;
7328 }
7329 
7330 static void rbd_slab_exit(void)
7331 {
7332         rbd_assert(rbd_obj_request_cache);
7333         kmem_cache_destroy(rbd_obj_request_cache);
7334         rbd_obj_request_cache = NULL;
7335 
7336         rbd_assert(rbd_img_request_cache);
7337         kmem_cache_destroy(rbd_img_request_cache);
7338         rbd_img_request_cache = NULL;
7339 }
7340 
7341 static int __init rbd_init(void)
7342 {
7343         int rc;
7344 
7345         if (!libceph_compatible(NULL)) {
7346                 rbd_warn(NULL, "libceph incompatibility (quitting)");
7347                 return -EINVAL;
7348         }
7349 
7350         rc = rbd_slab_init();
7351         if (rc)
7352                 return rc;
7353 
7354         /*
7355          * The number of active work items is limited by the number of
7356          * rbd devices * queue depth, so leave @max_active at default.
7357          */
7358         rbd_wq = alloc_workqueue(RBD_DRV_NAME, WQ_MEM_RECLAIM, 0);
7359         if (!rbd_wq) {
7360                 rc = -ENOMEM;
7361                 goto err_out_slab;
7362         }
7363 
7364         if (single_major) {
7365                 rbd_major = register_blkdev(0, RBD_DRV_NAME);
7366                 if (rbd_major < 0) {
7367                         rc = rbd_major;
7368                         goto err_out_wq;
7369                 }
7370         }
7371 
7372         rc = rbd_sysfs_init();
7373         if (rc)
7374                 goto err_out_blkdev;
7375 
7376         if (single_major)
7377                 pr_info("loaded (major %d)\n", rbd_major);
7378         else
7379                 pr_info("loaded\n");
7380 
7381         return 0;
7382 
7383 err_out_blkdev:
7384         if (single_major)
7385                 unregister_blkdev(rbd_major, RBD_DRV_NAME);
7386 err_out_wq:
7387         destroy_workqueue(rbd_wq);
7388 err_out_slab:
7389         rbd_slab_exit();
7390         return rc;
7391 }
7392 
7393 static void __exit rbd_exit(void)
7394 {
7395         ida_destroy(&rbd_dev_id_ida);
7396         rbd_sysfs_cleanup();
7397         if (single_major)
7398                 unregister_blkdev(rbd_major, RBD_DRV_NAME);
7399         destroy_workqueue(rbd_wq);
7400         rbd_slab_exit();
7401 }
7402 
7403 module_init(rbd_init);
7404 module_exit(rbd_exit);
7405 
7406 MODULE_AUTHOR("Alex Elder <elder@inktank.com>");
7407 MODULE_AUTHOR("Sage Weil <sage@newdream.net>");
7408 MODULE_AUTHOR("Yehuda Sadeh <yehuda@hq.newdream.net>");
7409 /* following authorship retained from original osdblk.c */
7410 MODULE_AUTHOR("Jeff Garzik <jeff@garzik.org>");
7411 
7412 MODULE_DESCRIPTION("RADOS Block Device (RBD) driver");
7413 MODULE_LICENSE("GPL");