root/drivers/block/drbd/drbd_int.h

INCLUDED FROM

DEFINITIONS

1. drbd_insert_fault
2. bm_xfer_ctx_bit_to_word_offset
3. get_t_state
4. has_net_conf
5. minor_to_device
6. first_peer_device
7. conn_peer_device
8. device_to_minor
9. drbd_determine_dev_size
10. drbd_tcp_cork
11. drbd_tcp_uncork
12. drbd_tcp_nodelay
13. drbd_tcp_quickack
14. drbd_generic_make_request
15. page_chain_next
16. drbd_peer_req_has_active_page
17. drbd_read_state
18. __drbd_chk_io_error_
19. drbd_chk_io_error_
20. drbd_md_first_sector
21. drbd_md_last_sector
22. drbd_get_capacity
23. drbd_get_max_capacity
24. drbd_md_ss
25. drbd_queue_work
26. drbd_queue_work_if_unqueued
27. drbd_device_post_work
28. wake_ack_receiver
29. request_ping
30. drbd_thread_stop
31. drbd_thread_stop_nowait
32. drbd_thread_restart_nowait
33. inc_ap_pending
34. _dec_ap_pending
35. inc_rs_pending
36. _dec_rs_pending
37. inc_unacked
38. _dec_unacked
39. _sub_unacked
40. is_sync_target_state
41. is_sync_source_state
42. is_sync_state
43. put_ldev
44. _get_ldev_if_state
45. drbd_get_max_buffers
46. drbd_state_is_stable
47. drbd_suspended
48. may_inc_ap_bio
49. inc_ap_bio_cond
50. inc_ap_bio
51. dec_ap_bio
52. verify_can_do_stop_sector
53. drbd_set_ed_uuid
54. drbd_queue_order_type
55. first_connection

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3   drbd_int.h
   4 
   5   This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
   6 
   7   Copyright (C) 2001-2008, LINBIT Information Technologies GmbH.
   8   Copyright (C) 1999-2008, Philipp Reisner <philipp.reisner@linbit.com>.
   9   Copyright (C) 2002-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
  10 
  11 
  12 */
  13 
  14 #ifndef _DRBD_INT_H
  15 #define _DRBD_INT_H
  16 
  17 #include <crypto/hash.h>
  18 #include <linux/compiler.h>
  19 #include <linux/types.h>
  20 #include <linux/list.h>
  21 #include <linux/sched/signal.h>
  22 #include <linux/bitops.h>
  23 #include <linux/slab.h>
  24 #include <linux/ratelimit.h>
  25 #include <linux/tcp.h>
  26 #include <linux/mutex.h>
  27 #include <linux/major.h>
  28 #include <linux/blkdev.h>
  29 #include <linux/backing-dev.h>
  30 #include <linux/genhd.h>
  31 #include <linux/idr.h>
  32 #include <linux/dynamic_debug.h>
  33 #include <net/tcp.h>
  34 #include <linux/lru_cache.h>
  35 #include <linux/prefetch.h>
  36 #include <linux/drbd_genl_api.h>
  37 #include <linux/drbd.h>
  38 #include "drbd_strings.h"
  39 #include "drbd_state.h"
  40 #include "drbd_protocol.h"
  41 
  42 #ifdef __CHECKER__
  43 # define __protected_by(x)       __attribute__((require_context(x,1,999,"rdwr")))
  44 # define __protected_read_by(x)  __attribute__((require_context(x,1,999,"read")))
  45 # define __protected_write_by(x) __attribute__((require_context(x,1,999,"write")))
  46 #else
  47 # define __protected_by(x)
  48 # define __protected_read_by(x)
  49 # define __protected_write_by(x)
  50 #endif
  51 
  52 /* shared module parameters, defined in drbd_main.c */
  53 #ifdef CONFIG_DRBD_FAULT_INJECTION
  54 extern int drbd_enable_faults;
  55 extern int drbd_fault_rate;
  56 #endif
  57 
  58 extern unsigned int drbd_minor_count;
  59 extern char drbd_usermode_helper[];
  60 extern int drbd_proc_details;
  61 
  62 
  63 /* This is used to stop/restart our threads.
  64  * Cannot use SIGTERM nor SIGKILL, since these
  65  * are sent out by init on runlevel changes
  66  * I choose SIGHUP for now.
  67  */
  68 #define DRBD_SIGKILL SIGHUP
  69 
  70 #define ID_IN_SYNC      (4711ULL)
  71 #define ID_OUT_OF_SYNC  (4712ULL)
  72 #define ID_SYNCER (-1ULL)
  73 
  74 #define UUID_NEW_BM_OFFSET ((u64)0x0001000000000000ULL)
  75 
  76 struct drbd_device;
  77 struct drbd_connection;
  78 
  79 #define __drbd_printk_device(level, device, fmt, args...) \
  80         dev_printk(level, disk_to_dev((device)->vdisk), fmt, ## args)
  81 #define __drbd_printk_peer_device(level, peer_device, fmt, args...) \
  82         dev_printk(level, disk_to_dev((peer_device)->device->vdisk), fmt, ## args)
  83 #define __drbd_printk_resource(level, resource, fmt, args...) \
  84         printk(level "drbd %s: " fmt, (resource)->name, ## args)
  85 #define __drbd_printk_connection(level, connection, fmt, args...) \
  86         printk(level "drbd %s: " fmt, (connection)->resource->name, ## args)
  87 
  88 void drbd_printk_with_wrong_object_type(void);
  89 
  90 #define __drbd_printk_if_same_type(obj, type, func, level, fmt, args...) \
  91         (__builtin_types_compatible_p(typeof(obj), type) || \
  92          __builtin_types_compatible_p(typeof(obj), const type)), \
  93         func(level, (const type)(obj), fmt, ## args)
  94 
  95 #define drbd_printk(level, obj, fmt, args...) \
  96         __builtin_choose_expr( \
  97           __drbd_printk_if_same_type(obj, struct drbd_device *, \
  98                              __drbd_printk_device, level, fmt, ## args), \
  99           __builtin_choose_expr( \
 100             __drbd_printk_if_same_type(obj, struct drbd_resource *, \
 101                                __drbd_printk_resource, level, fmt, ## args), \
 102             __builtin_choose_expr( \
 103               __drbd_printk_if_same_type(obj, struct drbd_connection *, \
 104                                  __drbd_printk_connection, level, fmt, ## args), \
 105               __builtin_choose_expr( \
 106                 __drbd_printk_if_same_type(obj, struct drbd_peer_device *, \
 107                                  __drbd_printk_peer_device, level, fmt, ## args), \
 108                 drbd_printk_with_wrong_object_type()))))
 109 
 110 #define drbd_dbg(obj, fmt, args...) \
 111         drbd_printk(KERN_DEBUG, obj, fmt, ## args)
 112 #define drbd_alert(obj, fmt, args...) \
 113         drbd_printk(KERN_ALERT, obj, fmt, ## args)
 114 #define drbd_err(obj, fmt, args...) \
 115         drbd_printk(KERN_ERR, obj, fmt, ## args)
 116 #define drbd_warn(obj, fmt, args...) \
 117         drbd_printk(KERN_WARNING, obj, fmt, ## args)
 118 #define drbd_info(obj, fmt, args...) \
 119         drbd_printk(KERN_INFO, obj, fmt, ## args)
 120 #define drbd_emerg(obj, fmt, args...) \
 121         drbd_printk(KERN_EMERG, obj, fmt, ## args)
 122 
 123 #define dynamic_drbd_dbg(device, fmt, args...) \
 124         dynamic_dev_dbg(disk_to_dev(device->vdisk), fmt, ## args)
 125 
 126 #define D_ASSERT(device, exp)   do { \
 127         if (!(exp)) \
 128                 drbd_err(device, "ASSERT( " #exp " ) in %s:%d\n", __FILE__, __LINE__); \
 129         } while (0)
 130 
 131 /**
 132  * expect  -  Make an assertion
 133  *
 134  * Unlike the assert macro, this macro returns a boolean result.
 135  */
 136 #define expect(exp) ({                                                          \
 137                 bool _bool = (exp);                                             \
 138                 if (!_bool)                                                     \
 139                         drbd_err(device, "ASSERTION %s FAILED in %s\n",         \
 140                                 #exp, __func__);                                \
 141                 _bool;                                                          \
 142                 })
 143 
 144 /* Defines to control fault insertion */
 145 enum {
 146         DRBD_FAULT_MD_WR = 0,   /* meta data write */
 147         DRBD_FAULT_MD_RD = 1,   /*           read  */
 148         DRBD_FAULT_RS_WR = 2,   /* resync          */
 149         DRBD_FAULT_RS_RD = 3,
 150         DRBD_FAULT_DT_WR = 4,   /* data            */
 151         DRBD_FAULT_DT_RD = 5,
 152         DRBD_FAULT_DT_RA = 6,   /* data read ahead */
 153         DRBD_FAULT_BM_ALLOC = 7,        /* bitmap allocation */
 154         DRBD_FAULT_AL_EE = 8,   /* alloc ee */
 155         DRBD_FAULT_RECEIVE = 9, /* Changes some bytes upon receiving a [rs]data block */
 156 
 157         DRBD_FAULT_MAX,
 158 };
 159 
 160 extern unsigned int
 161 _drbd_insert_fault(struct drbd_device *device, unsigned int type);
 162 
 163 static inline int
 164 drbd_insert_fault(struct drbd_device *device, unsigned int type) {
 165 #ifdef CONFIG_DRBD_FAULT_INJECTION
 166         return drbd_fault_rate &&
 167                 (drbd_enable_faults & (1<<type)) &&
 168                 _drbd_insert_fault(device, type);
 169 #else
 170         return 0;
 171 #endif
 172 }
 173 
 174 /* integer division, round _UP_ to the next integer */
 175 #define div_ceil(A, B) ((A)/(B) + ((A)%(B) ? 1 : 0))
 176 /* usual integer division */
 177 #define div_floor(A, B) ((A)/(B))
 178 
 179 extern struct ratelimit_state drbd_ratelimit_state;
 180 extern struct idr drbd_devices; /* RCU, updates: genl_lock() */
 181 extern struct list_head drbd_resources; /* RCU, updates: genl_lock() */
 182 
 183 extern const char *cmdname(enum drbd_packet cmd);
 184 
 185 /* for sending/receiving the bitmap,
 186  * possibly in some encoding scheme */
 187 struct bm_xfer_ctx {
 188         /* "const"
 189          * stores total bits and long words
 190          * of the bitmap, so we don't need to
 191          * call the accessor functions over and again. */
 192         unsigned long bm_bits;
 193         unsigned long bm_words;
 194         /* during xfer, current position within the bitmap */
 195         unsigned long bit_offset;
 196         unsigned long word_offset;
 197 
 198         /* statistics; index: (h->command == P_BITMAP) */
 199         unsigned packets[2];
 200         unsigned bytes[2];
 201 };
 202 
 203 extern void INFO_bm_xfer_stats(struct drbd_device *device,
 204                 const char *direction, struct bm_xfer_ctx *c);
 205 
 206 static inline void bm_xfer_ctx_bit_to_word_offset(struct bm_xfer_ctx *c)
 207 {
 208         /* word_offset counts "native long words" (32 or 64 bit),
 209          * aligned at 64 bit.
 210          * Encoded packet may end at an unaligned bit offset.
 211          * In case a fallback clear text packet is transmitted in
 212          * between, we adjust this offset back to the last 64bit
 213          * aligned "native long word", which makes coding and decoding
 214          * the plain text bitmap much more convenient.  */
 215 #if BITS_PER_LONG == 64
 216         c->word_offset = c->bit_offset >> 6;
 217 #elif BITS_PER_LONG == 32
 218         c->word_offset = c->bit_offset >> 5;
 219         c->word_offset &= ~(1UL);
 220 #else
 221 # error "unsupported BITS_PER_LONG"
 222 #endif
 223 }
 224 
 225 extern unsigned int drbd_header_size(struct drbd_connection *connection);
 226 
 227 /**********************************************************************/
 228 enum drbd_thread_state {
 229         NONE,
 230         RUNNING,
 231         EXITING,
 232         RESTARTING
 233 };
 234 
 235 struct drbd_thread {
 236         spinlock_t t_lock;
 237         struct task_struct *task;
 238         struct completion stop;
 239         enum drbd_thread_state t_state;
 240         int (*function) (struct drbd_thread *);
 241         struct drbd_resource *resource;
 242         struct drbd_connection *connection;
 243         int reset_cpu_mask;
 244         const char *name;
 245 };
 246 
 247 static inline enum drbd_thread_state get_t_state(struct drbd_thread *thi)
 248 {
 249         /* THINK testing the t_state seems to be uncritical in all cases
 250          * (but thread_{start,stop}), so we can read it *without* the lock.
 251          *      --lge */
 252 
 253         smp_rmb();
 254         return thi->t_state;
 255 }
 256 
 257 struct drbd_work {
 258         struct list_head list;
 259         int (*cb)(struct drbd_work *, int cancel);
 260 };
 261 
 262 struct drbd_device_work {
 263         struct drbd_work w;
 264         struct drbd_device *device;
 265 };
 266 
 267 #include "drbd_interval.h"
 268 
 269 extern int drbd_wait_misc(struct drbd_device *, struct drbd_interval *);
 270 
 271 extern void lock_all_resources(void);
 272 extern void unlock_all_resources(void);
 273 
 274 struct drbd_request {
 275         struct drbd_work w;
 276         struct drbd_device *device;
 277 
 278         /* if local IO is not allowed, will be NULL.
 279          * if local IO _is_ allowed, holds the locally submitted bio clone,
 280          * or, after local IO completion, the ERR_PTR(error).
 281          * see drbd_request_endio(). */
 282         struct bio *private_bio;
 283 
 284         struct drbd_interval i;
 285 
 286         /* epoch: used to check on "completion" whether this req was in
 287          * the current epoch, and we therefore have to close it,
 288          * causing a p_barrier packet to be send, starting a new epoch.
 289          *
 290          * This corresponds to "barrier" in struct p_barrier[_ack],
 291          * and to "barrier_nr" in struct drbd_epoch (and various
 292          * comments/function parameters/local variable names).
 293          */
 294         unsigned int epoch;
 295 
 296         struct list_head tl_requests; /* ring list in the transfer log */
 297         struct bio *master_bio;       /* master bio pointer */
 298 
 299         /* see struct drbd_device */
 300         struct list_head req_pending_master_completion;
 301         struct list_head req_pending_local;
 302 
 303         /* for generic IO accounting */
 304         unsigned long start_jif;
 305 
 306         /* for DRBD internal statistics */
 307 
 308         /* Minimal set of time stamps to determine if we wait for activity log
 309          * transactions, local disk or peer.  32 bit "jiffies" are good enough,
 310          * we don't expect a DRBD request to be stalled for several month.
 311          */
 312 
 313         /* before actual request processing */
 314         unsigned long in_actlog_jif;
 315 
 316         /* local disk */
 317         unsigned long pre_submit_jif;
 318 
 319         /* per connection */
 320         unsigned long pre_send_jif;
 321         unsigned long acked_jif;
 322         unsigned long net_done_jif;
 323 
 324         /* Possibly even more detail to track each phase:
 325          *  master_completion_jif
 326          *      how long did it take to complete the master bio
 327          *      (application visible latency)
 328          *  allocated_jif
 329          *      how long the master bio was blocked until we finally allocated
 330          *      a tracking struct
 331          *  in_actlog_jif
 332          *      how long did we wait for activity log transactions
 333          *
 334          *  net_queued_jif
 335          *      when did we finally queue it for sending
 336          *  pre_send_jif
 337          *      when did we start sending it
 338          *  post_send_jif
 339          *      how long did we block in the network stack trying to send it
 340          *  acked_jif
 341          *      when did we receive (or fake, in protocol A) a remote ACK
 342          *  net_done_jif
 343          *      when did we receive final acknowledgement (P_BARRIER_ACK),
 344          *      or decide, e.g. on connection loss, that we do no longer expect
 345          *      anything from this peer for this request.
 346          *
 347          *  pre_submit_jif
 348          *  post_sub_jif
 349          *      when did we start submiting to the lower level device,
 350          *      and how long did we block in that submit function
 351          *  local_completion_jif
 352          *      how long did it take the lower level device to complete this request
 353          */
 354 
 355 
 356         /* once it hits 0, we may complete the master_bio */
 357         atomic_t completion_ref;
 358         /* once it hits 0, we may destroy this drbd_request object */
 359         struct kref kref;
 360 
 361         unsigned rq_state; /* see comments above _req_mod() */
 362 };
 363 
 364 struct drbd_epoch {
 365         struct drbd_connection *connection;
 366         struct list_head list;
 367         unsigned int barrier_nr;
 368         atomic_t epoch_size; /* increased on every request added. */
 369         atomic_t active;     /* increased on every req. added, and dec on every finished. */
 370         unsigned long flags;
 371 };
 372 
 373 /* Prototype declaration of function defined in drbd_receiver.c */
 374 int drbdd_init(struct drbd_thread *);
 375 int drbd_asender(struct drbd_thread *);
 376 
 377 /* drbd_epoch flag bits */
 378 enum {
 379         DE_HAVE_BARRIER_NUMBER,
 380 };
 381 
 382 enum epoch_event {
 383         EV_PUT,
 384         EV_GOT_BARRIER_NR,
 385         EV_BECAME_LAST,
 386         EV_CLEANUP = 32, /* used as flag */
 387 };
 388 
 389 struct digest_info {
 390         int digest_size;
 391         void *digest;
 392 };
 393 
 394 struct drbd_peer_request {
 395         struct drbd_work w;
 396         struct drbd_peer_device *peer_device;
 397         struct drbd_epoch *epoch; /* for writes */
 398         struct page *pages;
 399         atomic_t pending_bios;
 400         struct drbd_interval i;
 401         /* see comments on ee flag bits below */
 402         unsigned long flags;
 403         unsigned long submit_jif;
 404         union {
 405                 u64 block_id;
 406                 struct digest_info *digest;
 407         };
 408 };
 409 
 410 /* ee flag bits.
 411  * While corresponding bios are in flight, the only modification will be
 412  * set_bit WAS_ERROR, which has to be atomic.
 413  * If no bios are in flight yet, or all have been completed,
 414  * non-atomic modification to ee->flags is ok.
 415  */
 416 enum {
 417         __EE_CALL_AL_COMPLETE_IO,
 418         __EE_MAY_SET_IN_SYNC,
 419 
 420         /* is this a TRIM aka REQ_OP_DISCARD? */
 421         __EE_TRIM,
 422         /* explicit zero-out requested, or
 423          * our lower level cannot handle trim,
 424          * and we want to fall back to zeroout instead */
 425         __EE_ZEROOUT,
 426 
 427         /* In case a barrier failed,
 428          * we need to resubmit without the barrier flag. */
 429         __EE_RESUBMITTED,
 430 
 431         /* we may have several bios per peer request.
 432          * if any of those fail, we set this flag atomically
 433          * from the endio callback */
 434         __EE_WAS_ERROR,
 435 
 436         /* This ee has a pointer to a digest instead of a block id */
 437         __EE_HAS_DIGEST,
 438 
 439         /* Conflicting local requests need to be restarted after this request */
 440         __EE_RESTART_REQUESTS,
 441 
 442         /* The peer wants a write ACK for this (wire proto C) */
 443         __EE_SEND_WRITE_ACK,
 444 
 445         /* Is set when net_conf had two_primaries set while creating this peer_req */
 446         __EE_IN_INTERVAL_TREE,
 447 
 448         /* for debugfs: */
 449         /* has this been submitted, or does it still wait for something else? */
 450         __EE_SUBMITTED,
 451 
 452         /* this is/was a write request */
 453         __EE_WRITE,
 454 
 455         /* this is/was a write same request */
 456         __EE_WRITE_SAME,
 457 
 458         /* this originates from application on peer
 459          * (not some resync or verify or other DRBD internal request) */
 460         __EE_APPLICATION,
 461 
 462         /* If it contains only 0 bytes, send back P_RS_DEALLOCATED */
 463         __EE_RS_THIN_REQ,
 464 };
 465 #define EE_CALL_AL_COMPLETE_IO (1<<__EE_CALL_AL_COMPLETE_IO)
 466 #define EE_MAY_SET_IN_SYNC     (1<<__EE_MAY_SET_IN_SYNC)
 467 #define EE_TRIM                (1<<__EE_TRIM)
 468 #define EE_ZEROOUT             (1<<__EE_ZEROOUT)
 469 #define EE_RESUBMITTED         (1<<__EE_RESUBMITTED)
 470 #define EE_WAS_ERROR           (1<<__EE_WAS_ERROR)
 471 #define EE_HAS_DIGEST          (1<<__EE_HAS_DIGEST)
 472 #define EE_RESTART_REQUESTS     (1<<__EE_RESTART_REQUESTS)
 473 #define EE_SEND_WRITE_ACK       (1<<__EE_SEND_WRITE_ACK)
 474 #define EE_IN_INTERVAL_TREE     (1<<__EE_IN_INTERVAL_TREE)
 475 #define EE_SUBMITTED            (1<<__EE_SUBMITTED)
 476 #define EE_WRITE                (1<<__EE_WRITE)
 477 #define EE_WRITE_SAME           (1<<__EE_WRITE_SAME)
 478 #define EE_APPLICATION          (1<<__EE_APPLICATION)
 479 #define EE_RS_THIN_REQ          (1<<__EE_RS_THIN_REQ)
 480 
 481 /* flag bits per device */
 482 enum {
 483         UNPLUG_REMOTE,          /* sending a "UnplugRemote" could help */
 484         MD_DIRTY,               /* current uuids and flags not yet on disk */
 485         USE_DEGR_WFC_T,         /* degr-wfc-timeout instead of wfc-timeout. */
 486         CL_ST_CHG_SUCCESS,
 487         CL_ST_CHG_FAIL,
 488         CRASHED_PRIMARY,        /* This node was a crashed primary.
 489                                  * Gets cleared when the state.conn
 490                                  * goes into C_CONNECTED state. */
 491         CONSIDER_RESYNC,
 492 
 493         MD_NO_FUA,              /* Users wants us to not use FUA/FLUSH on meta data dev */
 494 
 495         BITMAP_IO,              /* suspend application io;
 496                                    once no more io in flight, start bitmap io */
 497         BITMAP_IO_QUEUED,       /* Started bitmap IO */
 498         WAS_IO_ERROR,           /* Local disk failed, returned IO error */
 499         WAS_READ_ERROR,         /* Local disk READ failed (set additionally to the above) */
 500         FORCE_DETACH,           /* Force-detach from local disk, aborting any pending local IO */
 501         RESYNC_AFTER_NEG,       /* Resync after online grow after the attach&negotiate finished. */
 502         RESIZE_PENDING,         /* Size change detected locally, waiting for the response from
 503                                  * the peer, if it changed there as well. */
 504         NEW_CUR_UUID,           /* Create new current UUID when thawing IO */
 505         AL_SUSPENDED,           /* Activity logging is currently suspended. */
 506         AHEAD_TO_SYNC_SOURCE,   /* Ahead -> SyncSource queued */
 507         B_RS_H_DONE,            /* Before resync handler done (already executed) */
 508         DISCARD_MY_DATA,        /* discard_my_data flag per volume */
 509         READ_BALANCE_RR,
 510 
 511         FLUSH_PENDING,          /* if set, device->flush_jif is when we submitted that flush
 512                                  * from drbd_flush_after_epoch() */
 513 
 514         /* cleared only after backing device related structures have been destroyed. */
 515         GOING_DISKLESS,         /* Disk is being detached, because of io-error, or admin request. */
 516 
 517         /* to be used in drbd_device_post_work() */
 518         GO_DISKLESS,            /* tell worker to schedule cleanup before detach */
 519         DESTROY_DISK,           /* tell worker to close backing devices and destroy related structures. */
 520         MD_SYNC,                /* tell worker to call drbd_md_sync() */
 521         RS_START,               /* tell worker to start resync/OV */
 522         RS_PROGRESS,            /* tell worker that resync made significant progress */
 523         RS_DONE,                /* tell worker that resync is done */
 524 };
 525 
 526 struct drbd_bitmap; /* opaque for drbd_device */
 527 
 528 /* definition of bits in bm_flags to be used in drbd_bm_lock
 529  * and drbd_bitmap_io and friends. */
 530 enum bm_flag {
 531         /* currently locked for bulk operation */
 532         BM_LOCKED_MASK = 0xf,
 533 
 534         /* in detail, that is: */
 535         BM_DONT_CLEAR = 0x1,
 536         BM_DONT_SET   = 0x2,
 537         BM_DONT_TEST  = 0x4,
 538 
 539         /* so we can mark it locked for bulk operation,
 540          * and still allow all non-bulk operations */
 541         BM_IS_LOCKED  = 0x8,
 542 
 543         /* (test bit, count bit) allowed (common case) */
 544         BM_LOCKED_TEST_ALLOWED = BM_DONT_CLEAR | BM_DONT_SET | BM_IS_LOCKED,
 545 
 546         /* testing bits, as well as setting new bits allowed, but clearing bits
 547          * would be unexpected.  Used during bitmap receive.  Setting new bits
 548          * requires sending of "out-of-sync" information, though. */
 549         BM_LOCKED_SET_ALLOWED = BM_DONT_CLEAR | BM_IS_LOCKED,
 550 
 551         /* for drbd_bm_write_copy_pages, everything is allowed,
 552          * only concurrent bulk operations are locked out. */
 553         BM_LOCKED_CHANGE_ALLOWED = BM_IS_LOCKED,
 554 };
 555 
 556 struct drbd_work_queue {
 557         struct list_head q;
 558         spinlock_t q_lock;  /* to protect the list. */
 559         wait_queue_head_t q_wait;
 560 };
 561 
 562 struct drbd_socket {
 563         struct mutex mutex;
 564         struct socket    *socket;
 565         /* this way we get our
 566          * send/receive buffers off the stack */
 567         void *sbuf;
 568         void *rbuf;
 569 };
 570 
 571 struct drbd_md {
 572         u64 md_offset;          /* sector offset to 'super' block */
 573 
 574         u64 la_size_sect;       /* last agreed size, unit sectors */
 575         spinlock_t uuid_lock;
 576         u64 uuid[UI_SIZE];
 577         u64 device_uuid;
 578         u32 flags;
 579         u32 md_size_sect;
 580 
 581         s32 al_offset;  /* signed relative sector offset to activity log */
 582         s32 bm_offset;  /* signed relative sector offset to bitmap */
 583 
 584         /* cached value of bdev->disk_conf->meta_dev_idx (see below) */
 585         s32 meta_dev_idx;
 586 
 587         /* see al_tr_number_to_on_disk_sector() */
 588         u32 al_stripes;
 589         u32 al_stripe_size_4k;
 590         u32 al_size_4k; /* cached product of the above */
 591 };
 592 
 593 struct drbd_backing_dev {
 594         struct block_device *backing_bdev;
 595         struct block_device *md_bdev;
 596         struct drbd_md md;
 597         struct disk_conf *disk_conf; /* RCU, for updates: resource->conf_update */
 598         sector_t known_size; /* last known size of that backing device */
 599 };
 600 
 601 struct drbd_md_io {
 602         struct page *page;
 603         unsigned long start_jif;        /* last call to drbd_md_get_buffer */
 604         unsigned long submit_jif;       /* last _drbd_md_sync_page_io() submit */
 605         const char *current_use;
 606         atomic_t in_use;
 607         unsigned int done;
 608         int error;
 609 };
 610 
 611 struct bm_io_work {
 612         struct drbd_work w;
 613         char *why;
 614         enum bm_flag flags;
 615         int (*io_fn)(struct drbd_device *device);
 616         void (*done)(struct drbd_device *device, int rv);
 617 };
 618 
 619 struct fifo_buffer {
 620         unsigned int head_index;
 621         unsigned int size;
 622         int total; /* sum of all values */
 623         int values[0];
 624 };
 625 extern struct fifo_buffer *fifo_alloc(int fifo_size);
 626 
 627 /* flag bits per connection */
 628 enum {
 629         NET_CONGESTED,          /* The data socket is congested */
 630         RESOLVE_CONFLICTS,      /* Set on one node, cleared on the peer! */
 631         SEND_PING,
 632         GOT_PING_ACK,           /* set when we receive a ping_ack packet, ping_wait gets woken */
 633         CONN_WD_ST_CHG_REQ,     /* A cluster wide state change on the connection is active */
 634         CONN_WD_ST_CHG_OKAY,
 635         CONN_WD_ST_CHG_FAIL,
 636         CONN_DRY_RUN,           /* Expect disconnect after resync handshake. */
 637         CREATE_BARRIER,         /* next P_DATA is preceded by a P_BARRIER */
 638         STATE_SENT,             /* Do not change state/UUIDs while this is set */
 639         CALLBACK_PENDING,       /* Whether we have a call_usermodehelper(, UMH_WAIT_PROC)
 640                                  * pending, from drbd worker context.
 641                                  * If set, bdi_write_congested() returns true,
 642                                  * so shrink_page_list() would not recurse into,
 643                                  * and potentially deadlock on, this drbd worker.
 644                                  */
 645         DISCONNECT_SENT,
 646 
 647         DEVICE_WORK_PENDING,    /* tell worker that some device has pending work */
 648 };
 649 
 650 enum which_state { NOW, OLD = NOW, NEW };
 651 
 652 struct drbd_resource {
 653         char *name;
 654 #ifdef CONFIG_DEBUG_FS
 655         struct dentry *debugfs_res;
 656         struct dentry *debugfs_res_volumes;
 657         struct dentry *debugfs_res_connections;
 658         struct dentry *debugfs_res_in_flight_summary;
 659 #endif
 660         struct kref kref;
 661         struct idr devices;             /* volume number to device mapping */
 662         struct list_head connections;
 663         struct list_head resources;
 664         struct res_opts res_opts;
 665         struct mutex conf_update;       /* mutex for ready-copy-update of net_conf and disk_conf */
 666         struct mutex adm_mutex;         /* mutex to serialize administrative requests */
 667         spinlock_t req_lock;
 668 
 669         unsigned susp:1;                /* IO suspended by user */
 670         unsigned susp_nod:1;            /* IO suspended because no data */
 671         unsigned susp_fen:1;            /* IO suspended because fence peer handler runs */
 672 
 673         enum write_ordering_e write_ordering;
 674 
 675         cpumask_var_t cpu_mask;
 676 };
 677 
 678 struct drbd_thread_timing_details
 679 {
 680         unsigned long start_jif;
 681         void *cb_addr;
 682         const char *caller_fn;
 683         unsigned int line;
 684         unsigned int cb_nr;
 685 };
 686 
 687 struct drbd_connection {
 688         struct list_head connections;
 689         struct drbd_resource *resource;
 690 #ifdef CONFIG_DEBUG_FS
 691         struct dentry *debugfs_conn;
 692         struct dentry *debugfs_conn_callback_history;
 693         struct dentry *debugfs_conn_oldest_requests;
 694 #endif
 695         struct kref kref;
 696         struct idr peer_devices;        /* volume number to peer device mapping */
 697         enum drbd_conns cstate;         /* Only C_STANDALONE to C_WF_REPORT_PARAMS */
 698         struct mutex cstate_mutex;      /* Protects graceful disconnects */
 699         unsigned int connect_cnt;       /* Inc each time a connection is established */
 700 
 701         unsigned long flags;
 702         struct net_conf *net_conf;      /* content protected by rcu */
 703         wait_queue_head_t ping_wait;    /* Woken upon reception of a ping, and a state change */
 704 
 705         struct sockaddr_storage my_addr;
 706         int my_addr_len;
 707         struct sockaddr_storage peer_addr;
 708         int peer_addr_len;
 709 
 710         struct drbd_socket data;        /* data/barrier/cstate/parameter packets */
 711         struct drbd_socket meta;        /* ping/ack (metadata) packets */
 712         int agreed_pro_version;         /* actually used protocol version */
 713         u32 agreed_features;
 714         unsigned long last_received;    /* in jiffies, either socket */
 715         unsigned int ko_count;
 716 
 717         struct list_head transfer_log;  /* all requests not yet fully processed */
 718 
 719         struct crypto_shash *cram_hmac_tfm;
 720         struct crypto_shash *integrity_tfm;  /* checksums we compute, updates protected by connection->data->mutex */
 721         struct crypto_shash *peer_integrity_tfm;  /* checksums we verify, only accessed from receiver thread  */
 722         struct crypto_shash *csums_tfm;
 723         struct crypto_shash *verify_tfm;
 724         void *int_dig_in;
 725         void *int_dig_vv;
 726 
 727         /* receiver side */
 728         struct drbd_epoch *current_epoch;
 729         spinlock_t epoch_lock;
 730         unsigned int epochs;
 731         atomic_t current_tle_nr;        /* transfer log epoch number */
 732         unsigned current_tle_writes;    /* writes seen within this tl epoch */
 733 
 734         unsigned long last_reconnect_jif;
 735         /* empty member on older kernels without blk_start_plug() */
 736         struct blk_plug receiver_plug;
 737         struct drbd_thread receiver;
 738         struct drbd_thread worker;
 739         struct drbd_thread ack_receiver;
 740         struct workqueue_struct *ack_sender;
 741 
 742         /* cached pointers,
 743          * so we can look up the oldest pending requests more quickly.
 744          * protected by resource->req_lock */
 745         struct drbd_request *req_next; /* DRBD 9: todo.req_next */
 746         struct drbd_request *req_ack_pending;
 747         struct drbd_request *req_not_net_done;
 748 
 749         /* sender side */
 750         struct drbd_work_queue sender_work;
 751 
 752 #define DRBD_THREAD_DETAILS_HIST        16
 753         unsigned int w_cb_nr; /* keeps counting up */
 754         unsigned int r_cb_nr; /* keeps counting up */
 755         struct drbd_thread_timing_details w_timing_details[DRBD_THREAD_DETAILS_HIST];
 756         struct drbd_thread_timing_details r_timing_details[DRBD_THREAD_DETAILS_HIST];
 757 
 758         struct {
 759                 unsigned long last_sent_barrier_jif;
 760 
 761                 /* whether this sender thread
 762                  * has processed a single write yet. */
 763                 bool seen_any_write_yet;
 764 
 765                 /* Which barrier number to send with the next P_BARRIER */
 766                 int current_epoch_nr;
 767 
 768                 /* how many write requests have been sent
 769                  * with req->epoch == current_epoch_nr.
 770                  * If none, no P_BARRIER will be sent. */
 771                 unsigned current_epoch_writes;
 772         } send;
 773 };
 774 
 775 static inline bool has_net_conf(struct drbd_connection *connection)
 776 {
 777         bool has_net_conf;
 778 
 779         rcu_read_lock();
 780         has_net_conf = rcu_dereference(connection->net_conf);
 781         rcu_read_unlock();
 782 
 783         return has_net_conf;
 784 }
 785 
 786 void __update_timing_details(
 787                 struct drbd_thread_timing_details *tdp,
 788                 unsigned int *cb_nr,
 789                 void *cb,
 790                 const char *fn, const unsigned int line);
 791 
 792 #define update_worker_timing_details(c, cb) \
 793         __update_timing_details(c->w_timing_details, &c->w_cb_nr, cb, __func__ , __LINE__ )
 794 #define update_receiver_timing_details(c, cb) \
 795         __update_timing_details(c->r_timing_details, &c->r_cb_nr, cb, __func__ , __LINE__ )
 796 
 797 struct submit_worker {
 798         struct workqueue_struct *wq;
 799         struct work_struct worker;
 800 
 801         /* protected by ..->resource->req_lock */
 802         struct list_head writes;
 803 };
 804 
 805 struct drbd_peer_device {
 806         struct list_head peer_devices;
 807         struct drbd_device *device;
 808         struct drbd_connection *connection;
 809         struct work_struct send_acks_work;
 810 #ifdef CONFIG_DEBUG_FS
 811         struct dentry *debugfs_peer_dev;
 812 #endif
 813 };
 814 
 815 struct drbd_device {
 816         struct drbd_resource *resource;
 817         struct list_head peer_devices;
 818         struct list_head pending_bitmap_io;
 819 
 820         unsigned long flush_jif;
 821 #ifdef CONFIG_DEBUG_FS
 822         struct dentry *debugfs_minor;
 823         struct dentry *debugfs_vol;
 824         struct dentry *debugfs_vol_oldest_requests;
 825         struct dentry *debugfs_vol_act_log_extents;
 826         struct dentry *debugfs_vol_resync_extents;
 827         struct dentry *debugfs_vol_data_gen_id;
 828         struct dentry *debugfs_vol_ed_gen_id;
 829 #endif
 830 
 831         unsigned int vnr;       /* volume number within the connection */
 832         unsigned int minor;     /* device minor number */
 833 
 834         struct kref kref;
 835 
 836         /* things that are stored as / read from meta data on disk */
 837         unsigned long flags;
 838 
 839         /* configured by drbdsetup */
 840         struct drbd_backing_dev *ldev __protected_by(local);
 841 
 842         sector_t p_size;     /* partner's disk size */
 843         struct request_queue *rq_queue;
 844         struct block_device *this_bdev;
 845         struct gendisk      *vdisk;
 846 
 847         unsigned long last_reattach_jif;
 848         struct drbd_work resync_work;
 849         struct drbd_work unplug_work;
 850         struct timer_list resync_timer;
 851         struct timer_list md_sync_timer;
 852         struct timer_list start_resync_timer;
 853         struct timer_list request_timer;
 854 
 855         /* Used after attach while negotiating new disk state. */
 856         union drbd_state new_state_tmp;
 857 
 858         union drbd_dev_state state;
 859         wait_queue_head_t misc_wait;
 860         wait_queue_head_t state_wait;  /* upon each state change. */
 861         unsigned int send_cnt;
 862         unsigned int recv_cnt;
 863         unsigned int read_cnt;
 864         unsigned int writ_cnt;
 865         unsigned int al_writ_cnt;
 866         unsigned int bm_writ_cnt;
 867         atomic_t ap_bio_cnt;     /* Requests we need to complete */
 868         atomic_t ap_actlog_cnt;  /* Requests waiting for activity log */
 869         atomic_t ap_pending_cnt; /* AP data packets on the wire, ack expected */
 870         atomic_t rs_pending_cnt; /* RS request/data packets on the wire */
 871         atomic_t unacked_cnt;    /* Need to send replies for */
 872         atomic_t local_cnt;      /* Waiting for local completion */
 873         atomic_t suspend_cnt;
 874 
 875         /* Interval tree of pending local requests */
 876         struct rb_root read_requests;
 877         struct rb_root write_requests;
 878 
 879         /* for statistics and timeouts */
 880         /* [0] read, [1] write */
 881         struct list_head pending_master_completion[2];
 882         struct list_head pending_completion[2];
 883 
 884         /* use checksums for *this* resync */
 885         bool use_csums;
 886         /* blocks to resync in this run [unit BM_BLOCK_SIZE] */
 887         unsigned long rs_total;
 888         /* number of resync blocks that failed in this run */
 889         unsigned long rs_failed;
 890         /* Syncer's start time [unit jiffies] */
 891         unsigned long rs_start;
 892         /* cumulated time in PausedSyncX state [unit jiffies] */
 893         unsigned long rs_paused;
 894         /* skipped because csum was equal [unit BM_BLOCK_SIZE] */
 895         unsigned long rs_same_csum;
 896 #define DRBD_SYNC_MARKS 8
 897 #define DRBD_SYNC_MARK_STEP (3*HZ)
 898         /* block not up-to-date at mark [unit BM_BLOCK_SIZE] */
 899         unsigned long rs_mark_left[DRBD_SYNC_MARKS];
 900         /* marks's time [unit jiffies] */
 901         unsigned long rs_mark_time[DRBD_SYNC_MARKS];
 902         /* current index into rs_mark_{left,time} */
 903         int rs_last_mark;
 904         unsigned long rs_last_bcast; /* [unit jiffies] */
 905 
 906         /* where does the admin want us to start? (sector) */
 907         sector_t ov_start_sector;
 908         sector_t ov_stop_sector;
 909         /* where are we now? (sector) */
 910         sector_t ov_position;
 911         /* Start sector of out of sync range (to merge printk reporting). */
 912         sector_t ov_last_oos_start;
 913         /* size of out-of-sync range in sectors. */
 914         sector_t ov_last_oos_size;
 915         unsigned long ov_left; /* in bits */
 916 
 917         struct drbd_bitmap *bitmap;
 918         unsigned long bm_resync_fo; /* bit offset for drbd_bm_find_next */
 919 
 920         /* Used to track operations of resync... */
 921         struct lru_cache *resync;
 922         /* Number of locked elements in resync LRU */
 923         unsigned int resync_locked;
 924         /* resync extent number waiting for application requests */
 925         unsigned int resync_wenr;
 926 
 927         int open_cnt;
 928         u64 *p_uuid;
 929 
 930         struct list_head active_ee; /* IO in progress (P_DATA gets written to disk) */
 931         struct list_head sync_ee;   /* IO in progress (P_RS_DATA_REPLY gets written to disk) */
 932         struct list_head done_ee;   /* need to send P_WRITE_ACK */
 933         struct list_head read_ee;   /* [RS]P_DATA_REQUEST being read */
 934         struct list_head net_ee;    /* zero-copy network send in progress */
 935 
 936         int next_barrier_nr;
 937         struct list_head resync_reads;
 938         atomic_t pp_in_use;             /* allocated from page pool */
 939         atomic_t pp_in_use_by_net;      /* sendpage()d, still referenced by tcp */
 940         wait_queue_head_t ee_wait;
 941         struct drbd_md_io md_io;
 942         spinlock_t al_lock;
 943         wait_queue_head_t al_wait;
 944         struct lru_cache *act_log;      /* activity log */
 945         unsigned int al_tr_number;
 946         int al_tr_cycle;
 947         wait_queue_head_t seq_wait;
 948         atomic_t packet_seq;
 949         unsigned int peer_seq;
 950         spinlock_t peer_seq_lock;
 951         unsigned long comm_bm_set; /* communicated number of set bits. */
 952         struct bm_io_work bm_io_work;
 953         u64 ed_uuid; /* UUID of the exposed data */
 954         struct mutex own_state_mutex;
 955         struct mutex *state_mutex; /* either own_state_mutex or first_peer_device(device)->connection->cstate_mutex */
 956         char congestion_reason;  /* Why we where congested... */
 957         atomic_t rs_sect_in; /* for incoming resync data rate, SyncTarget */
 958         atomic_t rs_sect_ev; /* for submitted resync data rate, both */
 959         int rs_last_sect_ev; /* counter to compare with */
 960         int rs_last_events;  /* counter of read or write "events" (unit sectors)
 961                               * on the lower level device when we last looked. */
 962         int c_sync_rate; /* current resync rate after syncer throttle magic */
 963         struct fifo_buffer *rs_plan_s; /* correction values of resync planer (RCU, connection->conn_update) */
 964         int rs_in_flight; /* resync sectors in flight (to proxy, in proxy and from proxy) */
 965         atomic_t ap_in_flight; /* App sectors in flight (waiting for ack) */
 966         unsigned int peer_max_bio_size;
 967         unsigned int local_max_bio_size;
 968 
 969         /* any requests that would block in drbd_make_request()
 970          * are deferred to this single-threaded work queue */
 971         struct submit_worker submit;
 972 };
 973 
 974 struct drbd_bm_aio_ctx {
 975         struct drbd_device *device;
 976         struct list_head list; /* on device->pending_bitmap_io */;
 977         unsigned long start_jif;
 978         atomic_t in_flight;
 979         unsigned int done;
 980         unsigned flags;
 981 #define BM_AIO_COPY_PAGES       1
 982 #define BM_AIO_WRITE_HINTED     2
 983 #define BM_AIO_WRITE_ALL_PAGES  4
 984 #define BM_AIO_READ             8
 985         int error;
 986         struct kref kref;
 987 };
 988 
 989 struct drbd_config_context {
 990         /* assigned from drbd_genlmsghdr */
 991         unsigned int minor;
 992         /* assigned from request attributes, if present */
 993         unsigned int volume;
 994 #define VOLUME_UNSPECIFIED              (-1U)
 995         /* pointer into the request skb,
 996          * limited lifetime! */
 997         char *resource_name;
 998         struct nlattr *my_addr;
 999         struct nlattr *peer_addr;
1000 
1001         /* reply buffer */
1002         struct sk_buff *reply_skb;
1003         /* pointer into reply buffer */
1004         struct drbd_genlmsghdr *reply_dh;
1005         /* resolved from attributes, if possible */
1006         struct drbd_device *device;
1007         struct drbd_resource *resource;
1008         struct drbd_connection *connection;
1009 };
1010 
1011 static inline struct drbd_device *minor_to_device(unsigned int minor)
1012 {
1013         return (struct drbd_device *)idr_find(&drbd_devices, minor);
1014 }
1015 
1016 static inline struct drbd_peer_device *first_peer_device(struct drbd_device *device)
1017 {
1018         return list_first_entry_or_null(&device->peer_devices, struct drbd_peer_device, peer_devices);
1019 }
1020 
1021 static inline struct drbd_peer_device *
1022 conn_peer_device(struct drbd_connection *connection, int volume_number)
1023 {
1024         return idr_find(&connection->peer_devices, volume_number);
1025 }
1026 
1027 #define for_each_resource(resource, _resources) \
1028         list_for_each_entry(resource, _resources, resources)
1029 
1030 #define for_each_resource_rcu(resource, _resources) \
1031         list_for_each_entry_rcu(resource, _resources, resources)
1032 
1033 #define for_each_resource_safe(resource, tmp, _resources) \
1034         list_for_each_entry_safe(resource, tmp, _resources, resources)
1035 
1036 #define for_each_connection(connection, resource) \
1037         list_for_each_entry(connection, &resource->connections, connections)
1038 
1039 #define for_each_connection_rcu(connection, resource) \
1040         list_for_each_entry_rcu(connection, &resource->connections, connections)
1041 
1042 #define for_each_connection_safe(connection, tmp, resource) \
1043         list_for_each_entry_safe(connection, tmp, &resource->connections, connections)
1044 
1045 #define for_each_peer_device(peer_device, device) \
1046         list_for_each_entry(peer_device, &device->peer_devices, peer_devices)
1047 
1048 #define for_each_peer_device_rcu(peer_device, device) \
1049         list_for_each_entry_rcu(peer_device, &device->peer_devices, peer_devices)
1050 
1051 #define for_each_peer_device_safe(peer_device, tmp, device) \
1052         list_for_each_entry_safe(peer_device, tmp, &device->peer_devices, peer_devices)
1053 
1054 static inline unsigned int device_to_minor(struct drbd_device *device)
1055 {
1056         return device->minor;
1057 }
1058 
1059 /*
1060  * function declarations
1061  *************************/
1062 
1063 /* drbd_main.c */
1064 
1065 enum dds_flags {
1066         DDSF_FORCED    = 1,
1067         DDSF_NO_RESYNC = 2, /* Do not run a resync for the new space */
1068 };
1069 
1070 extern void drbd_init_set_defaults(struct drbd_device *device);
1071 extern int  drbd_thread_start(struct drbd_thread *thi);
1072 extern void _drbd_thread_stop(struct drbd_thread *thi, int restart, int wait);
1073 #ifdef CONFIG_SMP
1074 extern void drbd_thread_current_set_cpu(struct drbd_thread *thi);
1075 #else
1076 #define drbd_thread_current_set_cpu(A) ({})
1077 #endif
1078 extern void tl_release(struct drbd_connection *, unsigned int barrier_nr,
1079                        unsigned int set_size);
1080 extern void tl_clear(struct drbd_connection *);
1081 extern void drbd_free_sock(struct drbd_connection *connection);
1082 extern int drbd_send(struct drbd_connection *connection, struct socket *sock,
1083                      void *buf, size_t size, unsigned msg_flags);
1084 extern int drbd_send_all(struct drbd_connection *, struct socket *, void *, size_t,
1085                          unsigned);
1086 
1087 extern int __drbd_send_protocol(struct drbd_connection *connection, enum drbd_packet cmd);
1088 extern int drbd_send_protocol(struct drbd_connection *connection);
1089 extern int drbd_send_uuids(struct drbd_peer_device *);
1090 extern int drbd_send_uuids_skip_initial_sync(struct drbd_peer_device *);
1091 extern void drbd_gen_and_send_sync_uuid(struct drbd_peer_device *);
1092 extern int drbd_send_sizes(struct drbd_peer_device *, int trigger_reply, enum dds_flags flags);
1093 extern int drbd_send_state(struct drbd_peer_device *, union drbd_state s);
1094 extern int drbd_send_current_state(struct drbd_peer_device *);
1095 extern int drbd_send_sync_param(struct drbd_peer_device *);
1096 extern void drbd_send_b_ack(struct drbd_connection *connection, u32 barrier_nr,
1097                             u32 set_size);
1098 extern int drbd_send_ack(struct drbd_peer_device *, enum drbd_packet,
1099                          struct drbd_peer_request *);
1100 extern void drbd_send_ack_rp(struct drbd_peer_device *, enum drbd_packet,
1101                              struct p_block_req *rp);
1102 extern void drbd_send_ack_dp(struct drbd_peer_device *, enum drbd_packet,
1103                              struct p_data *dp, int data_size);
1104 extern int drbd_send_ack_ex(struct drbd_peer_device *, enum drbd_packet,
1105                             sector_t sector, int blksize, u64 block_id);
1106 extern int drbd_send_out_of_sync(struct drbd_peer_device *, struct drbd_request *);
1107 extern int drbd_send_block(struct drbd_peer_device *, enum drbd_packet,
1108                            struct drbd_peer_request *);
1109 extern int drbd_send_dblock(struct drbd_peer_device *, struct drbd_request *req);
1110 extern int drbd_send_drequest(struct drbd_peer_device *, int cmd,
1111                               sector_t sector, int size, u64 block_id);
1112 extern int drbd_send_drequest_csum(struct drbd_peer_device *, sector_t sector,
1113                                    int size, void *digest, int digest_size,
1114                                    enum drbd_packet cmd);
1115 extern int drbd_send_ov_request(struct drbd_peer_device *, sector_t sector, int size);
1116 
1117 extern int drbd_send_bitmap(struct drbd_device *device);
1118 extern void drbd_send_sr_reply(struct drbd_peer_device *, enum drbd_state_rv retcode);
1119 extern void conn_send_sr_reply(struct drbd_connection *connection, enum drbd_state_rv retcode);
1120 extern int drbd_send_rs_deallocated(struct drbd_peer_device *, struct drbd_peer_request *);
1121 extern void drbd_backing_dev_free(struct drbd_device *device, struct drbd_backing_dev *ldev);
1122 extern void drbd_device_cleanup(struct drbd_device *device);
1123 extern void drbd_print_uuids(struct drbd_device *device, const char *text);
1124 extern void drbd_queue_unplug(struct drbd_device *device);
1125 
1126 extern void conn_md_sync(struct drbd_connection *connection);
1127 extern void drbd_md_write(struct drbd_device *device, void *buffer);
1128 extern void drbd_md_sync(struct drbd_device *device);
1129 extern int  drbd_md_read(struct drbd_device *device, struct drbd_backing_dev *bdev);
1130 extern void drbd_uuid_set(struct drbd_device *device, int idx, u64 val) __must_hold(local);
1131 extern void _drbd_uuid_set(struct drbd_device *device, int idx, u64 val) __must_hold(local);
1132 extern void drbd_uuid_new_current(struct drbd_device *device) __must_hold(local);
1133 extern void drbd_uuid_set_bm(struct drbd_device *device, u64 val) __must_hold(local);
1134 extern void drbd_uuid_move_history(struct drbd_device *device) __must_hold(local);
1135 extern void __drbd_uuid_set(struct drbd_device *device, int idx, u64 val) __must_hold(local);
1136 extern void drbd_md_set_flag(struct drbd_device *device, int flags) __must_hold(local);
1137 extern void drbd_md_clear_flag(struct drbd_device *device, int flags)__must_hold(local);
1138 extern int drbd_md_test_flag(struct drbd_backing_dev *, int);
1139 extern void drbd_md_mark_dirty(struct drbd_device *device);
1140 extern void drbd_queue_bitmap_io(struct drbd_device *device,
1141                                  int (*io_fn)(struct drbd_device *),
1142                                  void (*done)(struct drbd_device *, int),
1143                                  char *why, enum bm_flag flags);
1144 extern int drbd_bitmap_io(struct drbd_device *device,
1145                 int (*io_fn)(struct drbd_device *),
1146                 char *why, enum bm_flag flags);
1147 extern int drbd_bitmap_io_from_worker(struct drbd_device *device,
1148                 int (*io_fn)(struct drbd_device *),
1149                 char *why, enum bm_flag flags);
1150 extern int drbd_bmio_set_n_write(struct drbd_device *device) __must_hold(local);
1151 extern int drbd_bmio_clear_n_write(struct drbd_device *device) __must_hold(local);
1152 
1153 /* Meta data layout
1154  *
1155  * We currently have two possible layouts.
1156  * Offsets in (512 byte) sectors.
1157  * external:
1158  *   |----------- md_size_sect ------------------|
1159  *   [ 4k superblock ][ activity log ][  Bitmap  ]
1160  *   | al_offset == 8 |
1161  *   | bm_offset = al_offset + X      |
1162  *  ==> bitmap sectors = md_size_sect - bm_offset
1163  *
1164  *  Variants:
1165  *     old, indexed fixed size meta data:
1166  *
1167  * internal:
1168  *            |----------- md_size_sect ------------------|
1169  * [data.....][  Bitmap  ][ activity log ][ 4k superblock ][padding*]
1170  *                        | al_offset < 0 |
1171  *            | bm_offset = al_offset - Y |
1172  *  ==> bitmap sectors = Y = al_offset - bm_offset
1173  *
1174  *  [padding*] are zero or up to 7 unused 512 Byte sectors to the
1175  *  end of the device, so that the [4k superblock] will be 4k aligned.
1176  *
1177  *  The activity log consists of 4k transaction blocks,
1178  *  which are written in a ring-buffer, or striped ring-buffer like fashion,
1179  *  which are writtensize used to be fixed 32kB,
1180  *  but is about to become configurable.
1181  */
1182 
1183 /* Our old fixed size meta data layout
1184  * allows up to about 3.8TB, so if you want more,
1185  * you need to use the "flexible" meta data format. */
1186 #define MD_128MB_SECT (128LLU << 11)  /* 128 MB, unit sectors */
1187 #define MD_4kB_SECT      8
1188 #define MD_32kB_SECT    64
1189 
1190 /* One activity log extent represents 4M of storage */
1191 #define AL_EXTENT_SHIFT 22
1192 #define AL_EXTENT_SIZE (1<<AL_EXTENT_SHIFT)
1193 
1194 /* We could make these currently hardcoded constants configurable
1195  * variables at create-md time (or even re-configurable at runtime?).
1196  * Which will require some more changes to the DRBD "super block"
1197  * and attach code.
1198  *
1199  * updates per transaction:
1200  *   This many changes to the active set can be logged with one transaction.
1201  *   This number is arbitrary.
1202  * context per transaction:
1203  *   This many context extent numbers are logged with each transaction.
1204  *   This number is resulting from the transaction block size (4k), the layout
1205  *   of the transaction header, and the number of updates per transaction.
1206  *   See drbd_actlog.c:struct al_transaction_on_disk
1207  * */
1208 #define AL_UPDATES_PER_TRANSACTION       64     // arbitrary
1209 #define AL_CONTEXT_PER_TRANSACTION      919     // (4096 - 36 - 6*64)/4
1210 
1211 #if BITS_PER_LONG == 32
1212 #define LN2_BPL 5
1213 #define cpu_to_lel(A) cpu_to_le32(A)
1214 #define lel_to_cpu(A) le32_to_cpu(A)
1215 #elif BITS_PER_LONG == 64
1216 #define LN2_BPL 6
1217 #define cpu_to_lel(A) cpu_to_le64(A)
1218 #define lel_to_cpu(A) le64_to_cpu(A)
1219 #else
1220 #error "LN2 of BITS_PER_LONG unknown!"
1221 #endif
1222 
1223 /* resync bitmap */
1224 /* 16MB sized 'bitmap extent' to track syncer usage */
1225 struct bm_extent {
1226         int rs_left; /* number of bits set (out of sync) in this extent. */
1227         int rs_failed; /* number of failed resync requests in this extent. */
1228         unsigned long flags;
1229         struct lc_element lce;
1230 };
1231 
1232 #define BME_NO_WRITES  0  /* bm_extent.flags: no more requests on this one! */
1233 #define BME_LOCKED     1  /* bm_extent.flags: syncer active on this one. */
1234 #define BME_PRIORITY   2  /* finish resync IO on this extent ASAP! App IO waiting! */
1235 
1236 /* drbd_bitmap.c */
1237 /*
1238  * We need to store one bit for a block.
1239  * Example: 1GB disk @ 4096 byte blocks ==> we need 32 KB bitmap.
1240  * Bit 0 ==> local node thinks this block is binary identical on both nodes
1241  * Bit 1 ==> local node thinks this block needs to be synced.
1242  */
1243 
1244 #define SLEEP_TIME (HZ/10)
1245 
1246 /* We do bitmap IO in units of 4k blocks.
1247  * We also still have a hardcoded 4k per bit relation. */
1248 #define BM_BLOCK_SHIFT  12                       /* 4k per bit */
1249 #define BM_BLOCK_SIZE    (1<<BM_BLOCK_SHIFT)
1250 /* mostly arbitrarily set the represented size of one bitmap extent,
1251  * aka resync extent, to 16 MiB (which is also 512 Byte worth of bitmap
1252  * at 4k per bit resolution) */
1253 #define BM_EXT_SHIFT     24     /* 16 MiB per resync extent */
1254 #define BM_EXT_SIZE      (1<<BM_EXT_SHIFT)
1255 
1256 #if (BM_EXT_SHIFT != 24) || (BM_BLOCK_SHIFT != 12)
1257 #error "HAVE YOU FIXED drbdmeta AS WELL??"
1258 #endif
1259 
1260 /* thus many _storage_ sectors are described by one bit */
1261 #define BM_SECT_TO_BIT(x)   ((x)>>(BM_BLOCK_SHIFT-9))
1262 #define BM_BIT_TO_SECT(x)   ((sector_t)(x)<<(BM_BLOCK_SHIFT-9))
1263 #define BM_SECT_PER_BIT     BM_BIT_TO_SECT(1)
1264 
1265 /* bit to represented kilo byte conversion */
1266 #define Bit2KB(bits) ((bits)<<(BM_BLOCK_SHIFT-10))
1267 
1268 /* in which _bitmap_ extent (resp. sector) the bit for a certain
1269  * _storage_ sector is located in */
1270 #define BM_SECT_TO_EXT(x)   ((x)>>(BM_EXT_SHIFT-9))
1271 #define BM_BIT_TO_EXT(x)    ((x) >> (BM_EXT_SHIFT - BM_BLOCK_SHIFT))
1272 
1273 /* first storage sector a bitmap extent corresponds to */
1274 #define BM_EXT_TO_SECT(x)   ((sector_t)(x) << (BM_EXT_SHIFT-9))
1275 /* how much _storage_ sectors we have per bitmap extent */
1276 #define BM_SECT_PER_EXT     BM_EXT_TO_SECT(1)
1277 /* how many bits are covered by one bitmap extent (resync extent) */
1278 #define BM_BITS_PER_EXT     (1UL << (BM_EXT_SHIFT - BM_BLOCK_SHIFT))
1279 
1280 #define BM_BLOCKS_PER_BM_EXT_MASK  (BM_BITS_PER_EXT - 1)
1281 
1282 
1283 /* in one sector of the bitmap, we have this many activity_log extents. */
1284 #define AL_EXT_PER_BM_SECT  (1 << (BM_EXT_SHIFT - AL_EXTENT_SHIFT))
1285 
1286 /* the extent in "PER_EXTENT" below is an activity log extent
1287  * we need that many (long words/bytes) to store the bitmap
1288  *                   of one AL_EXTENT_SIZE chunk of storage.
1289  * we can store the bitmap for that many AL_EXTENTS within
1290  * one sector of the _on_disk_ bitmap:
1291  * bit   0        bit 37   bit 38            bit (512*8)-1
1292  *           ...|........|........|.. // ..|........|
1293  * sect. 0       `296     `304                     ^(512*8*8)-1
1294  *
1295 #define BM_WORDS_PER_EXT    ( (AL_EXT_SIZE/BM_BLOCK_SIZE) / BITS_PER_LONG )
1296 #define BM_BYTES_PER_EXT    ( (AL_EXT_SIZE/BM_BLOCK_SIZE) / 8 )  // 128
1297 #define BM_EXT_PER_SECT     ( 512 / BM_BYTES_PER_EXTENT )        //   4
1298  */
1299 
1300 #define DRBD_MAX_SECTORS_32 (0xffffffffLU)
1301 /* we have a certain meta data variant that has a fixed on-disk size of 128
1302  * MiB, of which 4k are our "superblock", and 32k are the fixed size activity
1303  * log, leaving this many sectors for the bitmap.
1304  */
1305 
1306 #define DRBD_MAX_SECTORS_FIXED_BM \
1307           ((MD_128MB_SECT - MD_32kB_SECT - MD_4kB_SECT) * (1LL<<(BM_EXT_SHIFT-9)))
1308 #define DRBD_MAX_SECTORS      DRBD_MAX_SECTORS_FIXED_BM
1309 /* 16 TB in units of sectors */
1310 #if BITS_PER_LONG == 32
1311 /* adjust by one page worth of bitmap,
1312  * so we won't wrap around in drbd_bm_find_next_bit.
1313  * you should use 64bit OS for that much storage, anyways. */
1314 #define DRBD_MAX_SECTORS_FLEX BM_BIT_TO_SECT(0xffff7fff)
1315 #else
1316 /* we allow up to 1 PiB now on 64bit architecture with "flexible" meta data */
1317 #define DRBD_MAX_SECTORS_FLEX (1UL << 51)
1318 /* corresponds to (1UL << 38) bits right now. */
1319 #endif
1320 
1321 /* Estimate max bio size as 256 * PAGE_SIZE,
1322  * so for typical PAGE_SIZE of 4k, that is (1<<20) Byte.
1323  * Since we may live in a mixed-platform cluster,
1324  * we limit us to a platform agnostic constant here for now.
1325  * A followup commit may allow even bigger BIO sizes,
1326  * once we thought that through. */
1327 #define DRBD_MAX_BIO_SIZE (1U << 20)
1328 #if DRBD_MAX_BIO_SIZE > (BIO_MAX_PAGES << PAGE_SHIFT)
1329 #error Architecture not supported: DRBD_MAX_BIO_SIZE > BIO_MAX_SIZE
1330 #endif
1331 #define DRBD_MAX_BIO_SIZE_SAFE (1U << 12)       /* Works always = 4k */
1332 
1333 #define DRBD_MAX_SIZE_H80_PACKET (1U << 15) /* Header 80 only allows packets up to 32KiB data */
1334 #define DRBD_MAX_BIO_SIZE_P95    (1U << 17) /* Protocol 95 to 99 allows bios up to 128KiB */
1335 
1336 /* For now, don't allow more than half of what we can "activate" in one
1337  * activity log transaction to be discarded in one go. We may need to rework
1338  * drbd_al_begin_io() to allow for even larger discard ranges */
1339 #define DRBD_MAX_BATCH_BIO_SIZE  (AL_UPDATES_PER_TRANSACTION/2*AL_EXTENT_SIZE)
1340 #define DRBD_MAX_BBIO_SECTORS    (DRBD_MAX_BATCH_BIO_SIZE >> 9)
1341 
1342 extern int  drbd_bm_init(struct drbd_device *device);
1343 extern int  drbd_bm_resize(struct drbd_device *device, sector_t sectors, int set_new_bits);
1344 extern void drbd_bm_cleanup(struct drbd_device *device);
1345 extern void drbd_bm_set_all(struct drbd_device *device);
1346 extern void drbd_bm_clear_all(struct drbd_device *device);
1347 /* set/clear/test only a few bits at a time */
1348 extern int  drbd_bm_set_bits(
1349                 struct drbd_device *device, unsigned long s, unsigned long e);
1350 extern int  drbd_bm_clear_bits(
1351                 struct drbd_device *device, unsigned long s, unsigned long e);
1352 extern int drbd_bm_count_bits(
1353         struct drbd_device *device, const unsigned long s, const unsigned long e);
1354 /* bm_set_bits variant for use while holding drbd_bm_lock,
1355  * may process the whole bitmap in one go */
1356 extern void _drbd_bm_set_bits(struct drbd_device *device,
1357                 const unsigned long s, const unsigned long e);
1358 extern int  drbd_bm_test_bit(struct drbd_device *device, unsigned long bitnr);
1359 extern int  drbd_bm_e_weight(struct drbd_device *device, unsigned long enr);
1360 extern int  drbd_bm_read(struct drbd_device *device) __must_hold(local);
1361 extern void drbd_bm_mark_for_writeout(struct drbd_device *device, int page_nr);
1362 extern int  drbd_bm_write(struct drbd_device *device) __must_hold(local);
1363 extern void drbd_bm_reset_al_hints(struct drbd_device *device) __must_hold(local);
1364 extern int  drbd_bm_write_hinted(struct drbd_device *device) __must_hold(local);
1365 extern int  drbd_bm_write_lazy(struct drbd_device *device, unsigned upper_idx) __must_hold(local);
1366 extern int drbd_bm_write_all(struct drbd_device *device) __must_hold(local);
1367 extern int  drbd_bm_write_copy_pages(struct drbd_device *device) __must_hold(local);
1368 extern size_t        drbd_bm_words(struct drbd_device *device);
1369 extern unsigned long drbd_bm_bits(struct drbd_device *device);
1370 extern sector_t      drbd_bm_capacity(struct drbd_device *device);
1371 
1372 #define DRBD_END_OF_BITMAP      (~(unsigned long)0)
1373 extern unsigned long drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo);
1374 /* bm_find_next variants for use while you hold drbd_bm_lock() */
1375 extern unsigned long _drbd_bm_find_next(struct drbd_device *device, unsigned long bm_fo);
1376 extern unsigned long _drbd_bm_find_next_zero(struct drbd_device *device, unsigned long bm_fo);
1377 extern unsigned long _drbd_bm_total_weight(struct drbd_device *device);
1378 extern unsigned long drbd_bm_total_weight(struct drbd_device *device);
1379 /* for receive_bitmap */
1380 extern void drbd_bm_merge_lel(struct drbd_device *device, size_t offset,
1381                 size_t number, unsigned long *buffer);
1382 /* for _drbd_send_bitmap */
1383 extern void drbd_bm_get_lel(struct drbd_device *device, size_t offset,
1384                 size_t number, unsigned long *buffer);
1385 
1386 extern void drbd_bm_lock(struct drbd_device *device, char *why, enum bm_flag flags);
1387 extern void drbd_bm_unlock(struct drbd_device *device);
1388 /* drbd_main.c */
1389 
1390 extern struct kmem_cache *drbd_request_cache;
1391 extern struct kmem_cache *drbd_ee_cache;        /* peer requests */
1392 extern struct kmem_cache *drbd_bm_ext_cache;    /* bitmap extents */
1393 extern struct kmem_cache *drbd_al_ext_cache;    /* activity log extents */
1394 extern mempool_t drbd_request_mempool;
1395 extern mempool_t drbd_ee_mempool;
1396 
1397 /* drbd's page pool, used to buffer data received from the peer,
1398  * or data requested by the peer.
1399  *
1400  * This does not have an emergency reserve.
1401  *
1402  * When allocating from this pool, it first takes pages from the pool.
1403  * Only if the pool is depleted will try to allocate from the system.
1404  *
1405  * The assumption is that pages taken from this pool will be processed,
1406  * and given back, "quickly", and then can be recycled, so we can avoid
1407  * frequent calls to alloc_page(), and still will be able to make progress even
1408  * under memory pressure.
1409  */
1410 extern struct page *drbd_pp_pool;
1411 extern spinlock_t   drbd_pp_lock;
1412 extern int          drbd_pp_vacant;
1413 extern wait_queue_head_t drbd_pp_wait;
1414 
1415 /* We also need a standard (emergency-reserve backed) page pool
1416  * for meta data IO (activity log, bitmap).
1417  * We can keep it global, as long as it is used as "N pages at a time".
1418  * 128 should be plenty, currently we probably can get away with as few as 1.
1419  */
1420 #define DRBD_MIN_POOL_PAGES     128
1421 extern mempool_t drbd_md_io_page_pool;
1422 
1423 /* We also need to make sure we get a bio
1424  * when we need it for housekeeping purposes */
1425 extern struct bio_set drbd_md_io_bio_set;
1426 /* to allocate from that set */
1427 extern struct bio *bio_alloc_drbd(gfp_t gfp_mask);
1428 
1429 /* And a bio_set for cloning */
1430 extern struct bio_set drbd_io_bio_set;
1431 
1432 extern struct mutex resources_mutex;
1433 
1434 extern int conn_lowest_minor(struct drbd_connection *connection);
1435 extern enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsigned int minor);
1436 extern void drbd_destroy_device(struct kref *kref);
1437 extern void drbd_delete_device(struct drbd_device *device);
1438 
1439 extern struct drbd_resource *drbd_create_resource(const char *name);
1440 extern void drbd_free_resource(struct drbd_resource *resource);
1441 
1442 extern int set_resource_options(struct drbd_resource *resource, struct res_opts *res_opts);
1443 extern struct drbd_connection *conn_create(const char *name, struct res_opts *res_opts);
1444 extern void drbd_destroy_connection(struct kref *kref);
1445 extern struct drbd_connection *conn_get_by_addrs(void *my_addr, int my_addr_len,
1446                                             void *peer_addr, int peer_addr_len);
1447 extern struct drbd_resource *drbd_find_resource(const char *name);
1448 extern void drbd_destroy_resource(struct kref *kref);
1449 extern void conn_free_crypto(struct drbd_connection *connection);
1450 
1451 /* drbd_req */
1452 extern void do_submit(struct work_struct *ws);
1453 extern void __drbd_make_request(struct drbd_device *, struct bio *, unsigned long);
1454 extern blk_qc_t drbd_make_request(struct request_queue *q, struct bio *bio);
1455 extern int drbd_read_remote(struct drbd_device *device, struct drbd_request *req);
1456 extern int is_valid_ar_handle(struct drbd_request *, sector_t);
1457 
1458 
1459 /* drbd_nl.c */
1460 
1461 extern struct mutex notification_mutex;
1462 
1463 extern void drbd_suspend_io(struct drbd_device *device);
1464 extern void drbd_resume_io(struct drbd_device *device);
1465 extern char *ppsize(char *buf, unsigned long long size);
1466 extern sector_t drbd_new_dev_size(struct drbd_device *, struct drbd_backing_dev *, sector_t, int);
1467 enum determine_dev_size {
1468         DS_ERROR_SHRINK = -3,
1469         DS_ERROR_SPACE_MD = -2,
1470         DS_ERROR = -1,
1471         DS_UNCHANGED = 0,
1472         DS_SHRUNK = 1,
1473         DS_GREW = 2,
1474         DS_GREW_FROM_ZERO = 3,
1475 };
1476 extern enum determine_dev_size
1477 drbd_determine_dev_size(struct drbd_device *, enum dds_flags, struct resize_parms *) __must_hold(local);
1478 extern void resync_after_online_grow(struct drbd_device *);
1479 extern void drbd_reconsider_queue_parameters(struct drbd_device *device,
1480                         struct drbd_backing_dev *bdev, struct o_qlim *o);
1481 extern enum drbd_state_rv drbd_set_role(struct drbd_device *device,
1482                                         enum drbd_role new_role,
1483                                         int force);
1484 extern bool conn_try_outdate_peer(struct drbd_connection *connection);
1485 extern void conn_try_outdate_peer_async(struct drbd_connection *connection);
1486 extern enum drbd_peer_state conn_khelper(struct drbd_connection *connection, char *cmd);
1487 extern int drbd_khelper(struct drbd_device *device, char *cmd);
1488 
1489 /* drbd_worker.c */
1490 /* bi_end_io handlers */
1491 extern void drbd_md_endio(struct bio *bio);
1492 extern void drbd_peer_request_endio(struct bio *bio);
1493 extern void drbd_request_endio(struct bio *bio);
1494 extern int drbd_worker(struct drbd_thread *thi);
1495 enum drbd_ret_code drbd_resync_after_valid(struct drbd_device *device, int o_minor);
1496 void drbd_resync_after_changed(struct drbd_device *device);
1497 extern void drbd_start_resync(struct drbd_device *device, enum drbd_conns side);
1498 extern void resume_next_sg(struct drbd_device *device);
1499 extern void suspend_other_sg(struct drbd_device *device);
1500 extern int drbd_resync_finished(struct drbd_device *device);
1501 /* maybe rather drbd_main.c ? */
1502 extern void *drbd_md_get_buffer(struct drbd_device *device, const char *intent);
1503 extern void drbd_md_put_buffer(struct drbd_device *device);
1504 extern int drbd_md_sync_page_io(struct drbd_device *device,
1505                 struct drbd_backing_dev *bdev, sector_t sector, int op);
1506 extern void drbd_ov_out_of_sync_found(struct drbd_device *, sector_t, int);
1507 extern void wait_until_done_or_force_detached(struct drbd_device *device,
1508                 struct drbd_backing_dev *bdev, unsigned int *done);
1509 extern void drbd_rs_controller_reset(struct drbd_device *device);
1510 
1511 static inline void ov_out_of_sync_print(struct drbd_device *device)
1512 {
1513         if (device->ov_last_oos_size) {
1514                 drbd_err(device, "Out of sync: start=%llu, size=%lu (sectors)\n",
1515                      (unsigned long long)device->ov_last_oos_start,
1516                      (unsigned long)device->ov_last_oos_size);
1517         }
1518         device->ov_last_oos_size = 0;
1519 }
1520 
1521 
1522 extern void drbd_csum_bio(struct crypto_shash *, struct bio *, void *);
1523 extern void drbd_csum_ee(struct crypto_shash *, struct drbd_peer_request *,
1524                          void *);
1525 /* worker callbacks */
1526 extern int w_e_end_data_req(struct drbd_work *, int);
1527 extern int w_e_end_rsdata_req(struct drbd_work *, int);
1528 extern int w_e_end_csum_rs_req(struct drbd_work *, int);
1529 extern int w_e_end_ov_reply(struct drbd_work *, int);
1530 extern int w_e_end_ov_req(struct drbd_work *, int);
1531 extern int w_ov_finished(struct drbd_work *, int);
1532 extern int w_resync_timer(struct drbd_work *, int);
1533 extern int w_send_write_hint(struct drbd_work *, int);
1534 extern int w_send_dblock(struct drbd_work *, int);
1535 extern int w_send_read_req(struct drbd_work *, int);
1536 extern int w_e_reissue(struct drbd_work *, int);
1537 extern int w_restart_disk_io(struct drbd_work *, int);
1538 extern int w_send_out_of_sync(struct drbd_work *, int);
1539 extern int w_start_resync(struct drbd_work *, int);
1540 
1541 extern void resync_timer_fn(struct timer_list *t);
1542 extern void start_resync_timer_fn(struct timer_list *t);
1543 
1544 extern void drbd_endio_write_sec_final(struct drbd_peer_request *peer_req);
1545 
1546 /* drbd_receiver.c */
1547 extern int drbd_issue_discard_or_zero_out(struct drbd_device *device,
1548                 sector_t start, unsigned int nr_sectors, int flags);
1549 extern int drbd_receiver(struct drbd_thread *thi);
1550 extern int drbd_ack_receiver(struct drbd_thread *thi);
1551 extern void drbd_send_ping_wf(struct work_struct *ws);
1552 extern void drbd_send_acks_wf(struct work_struct *ws);
1553 extern bool drbd_rs_c_min_rate_throttle(struct drbd_device *device);
1554 extern bool drbd_rs_should_slow_down(struct drbd_device *device, sector_t sector,
1555                 bool throttle_if_app_is_waiting);
1556 extern int drbd_submit_peer_request(struct drbd_device *,
1557                                     struct drbd_peer_request *, const unsigned,
1558                                     const unsigned, const int);
1559 extern int drbd_free_peer_reqs(struct drbd_device *, struct list_head *);
1560 extern struct drbd_peer_request *drbd_alloc_peer_req(struct drbd_peer_device *, u64,
1561                                                      sector_t, unsigned int,
1562                                                      unsigned int,
1563                                                      gfp_t) __must_hold(local);
1564 extern void __drbd_free_peer_req(struct drbd_device *, struct drbd_peer_request *,
1565                                  int);
1566 #define drbd_free_peer_req(m,e) __drbd_free_peer_req(m, e, 0)
1567 #define drbd_free_net_peer_req(m,e) __drbd_free_peer_req(m, e, 1)
1568 extern struct page *drbd_alloc_pages(struct drbd_peer_device *, unsigned int, bool);
1569 extern void drbd_set_recv_tcq(struct drbd_device *device, int tcq_enabled);
1570 extern void _drbd_clear_done_ee(struct drbd_device *device, struct list_head *to_be_freed);
1571 extern int drbd_connected(struct drbd_peer_device *);
1572 
1573 static inline void drbd_tcp_cork(struct socket *sock)
1574 {
1575         int val = 1;
1576         (void) kernel_setsockopt(sock, SOL_TCP, TCP_CORK,
1577                         (char*)&val, sizeof(val));
1578 }
1579 
1580 static inline void drbd_tcp_uncork(struct socket *sock)
1581 {
1582         int val = 0;
1583         (void) kernel_setsockopt(sock, SOL_TCP, TCP_CORK,
1584                         (char*)&val, sizeof(val));
1585 }
1586 
1587 static inline void drbd_tcp_nodelay(struct socket *sock)
1588 {
1589         int val = 1;
1590         (void) kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY,
1591                         (char*)&val, sizeof(val));
1592 }
1593 
1594 static inline void drbd_tcp_quickack(struct socket *sock)
1595 {
1596         int val = 2;
1597         (void) kernel_setsockopt(sock, SOL_TCP, TCP_QUICKACK,
1598                         (char*)&val, sizeof(val));
1599 }
1600 
1601 /* sets the number of 512 byte sectors of our virtual device */
1602 void drbd_set_my_capacity(struct drbd_device *device, sector_t size);
1603 
1604 /*
1605  * used to submit our private bio
1606  */
1607 static inline void drbd_generic_make_request(struct drbd_device *device,
1608                                              int fault_type, struct bio *bio)
1609 {
1610         __release(local);
1611         if (!bio->bi_disk) {
1612                 drbd_err(device, "drbd_generic_make_request: bio->bi_disk == NULL\n");
1613                 bio->bi_status = BLK_STS_IOERR;
1614                 bio_endio(bio);
1615                 return;
1616         }
1617 
1618         if (drbd_insert_fault(device, fault_type))
1619                 bio_io_error(bio);
1620         else
1621                 generic_make_request(bio);
1622 }
1623 
1624 void drbd_bump_write_ordering(struct drbd_resource *resource, struct drbd_backing_dev *bdev,
1625                               enum write_ordering_e wo);
1626 
1627 /* drbd_proc.c */
1628 extern struct proc_dir_entry *drbd_proc;
1629 int drbd_seq_show(struct seq_file *seq, void *v);
1630 
1631 /* drbd_actlog.c */
1632 extern bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i);
1633 extern int drbd_al_begin_io_nonblock(struct drbd_device *device, struct drbd_interval *i);
1634 extern void drbd_al_begin_io_commit(struct drbd_device *device);
1635 extern bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval *i);
1636 extern void drbd_al_begin_io(struct drbd_device *device, struct drbd_interval *i);
1637 extern void drbd_al_complete_io(struct drbd_device *device, struct drbd_interval *i);
1638 extern void drbd_rs_complete_io(struct drbd_device *device, sector_t sector);
1639 extern int drbd_rs_begin_io(struct drbd_device *device, sector_t sector);
1640 extern int drbd_try_rs_begin_io(struct drbd_device *device, sector_t sector);
1641 extern void drbd_rs_cancel_all(struct drbd_device *device);
1642 extern int drbd_rs_del_all(struct drbd_device *device);
1643 extern void drbd_rs_failed_io(struct drbd_device *device,
1644                 sector_t sector, int size);
1645 extern void drbd_advance_rs_marks(struct drbd_device *device, unsigned long still_to_go);
1646 
1647 enum update_sync_bits_mode { RECORD_RS_FAILED, SET_OUT_OF_SYNC, SET_IN_SYNC };
1648 extern int __drbd_change_sync(struct drbd_device *device, sector_t sector, int size,
1649                 enum update_sync_bits_mode mode);
1650 #define drbd_set_in_sync(device, sector, size) \
1651         __drbd_change_sync(device, sector, size, SET_IN_SYNC)
1652 #define drbd_set_out_of_sync(device, sector, size) \
1653         __drbd_change_sync(device, sector, size, SET_OUT_OF_SYNC)
1654 #define drbd_rs_failed_io(device, sector, size) \
1655         __drbd_change_sync(device, sector, size, RECORD_RS_FAILED)
1656 extern void drbd_al_shrink(struct drbd_device *device);
1657 extern int drbd_al_initialize(struct drbd_device *, void *);
1658 
1659 /* drbd_nl.c */
1660 /* state info broadcast */
1661 struct sib_info {
1662         enum drbd_state_info_bcast_reason sib_reason;
1663         union {
1664                 struct {
1665                         char *helper_name;
1666                         unsigned helper_exit_code;
1667                 };
1668                 struct {
1669                         union drbd_state os;
1670                         union drbd_state ns;
1671                 };
1672         };
1673 };
1674 void drbd_bcast_event(struct drbd_device *device, const struct sib_info *sib);
1675 
1676 extern void notify_resource_state(struct sk_buff *,
1677                                   unsigned int,
1678                                   struct drbd_resource *,
1679                                   struct resource_info *,
1680                                   enum drbd_notification_type);
1681 extern void notify_device_state(struct sk_buff *,
1682                                 unsigned int,
1683                                 struct drbd_device *,
1684                                 struct device_info *,
1685                                 enum drbd_notification_type);
1686 extern void notify_connection_state(struct sk_buff *,
1687                                     unsigned int,
1688                                     struct drbd_connection *,
1689                                     struct connection_info *,
1690                                     enum drbd_notification_type);
1691 extern void notify_peer_device_state(struct sk_buff *,
1692                                      unsigned int,
1693                                      struct drbd_peer_device *,
1694                                      struct peer_device_info *,
1695                                      enum drbd_notification_type);
1696 extern void notify_helper(enum drbd_notification_type, struct drbd_device *,
1697                           struct drbd_connection *, const char *, int);
1698 
1699 /*
1700  * inline helper functions
1701  *************************/
1702 
1703 /* see also page_chain_add and friends in drbd_receiver.c */
1704 static inline struct page *page_chain_next(struct page *page)
1705 {
1706         return (struct page *)page_private(page);
1707 }
1708 #define page_chain_for_each(page) \
1709         for (; page && ({ prefetch(page_chain_next(page)); 1; }); \
1710                         page = page_chain_next(page))
1711 #define page_chain_for_each_safe(page, n) \
1712         for (; page && ({ n = page_chain_next(page); 1; }); page = n)
1713 
1714 
1715 static inline int drbd_peer_req_has_active_page(struct drbd_peer_request *peer_req)
1716 {
1717         struct page *page = peer_req->pages;
1718         page_chain_for_each(page) {
1719                 if (page_count(page) > 1)
1720                         return 1;
1721         }
1722         return 0;
1723 }
1724 
1725 static inline union drbd_state drbd_read_state(struct drbd_device *device)
1726 {
1727         struct drbd_resource *resource = device->resource;
1728         union drbd_state rv;
1729 
1730         rv.i = device->state.i;
1731         rv.susp = resource->susp;
1732         rv.susp_nod = resource->susp_nod;
1733         rv.susp_fen = resource->susp_fen;
1734 
1735         return rv;
1736 }
1737 
1738 enum drbd_force_detach_flags {
1739         DRBD_READ_ERROR,
1740         DRBD_WRITE_ERROR,
1741         DRBD_META_IO_ERROR,
1742         DRBD_FORCE_DETACH,
1743 };
1744 
1745 #define __drbd_chk_io_error(m,f) __drbd_chk_io_error_(m,f, __func__)
1746 static inline void __drbd_chk_io_error_(struct drbd_device *device,
1747                 enum drbd_force_detach_flags df,
1748                 const char *where)
1749 {
1750         enum drbd_io_error_p ep;
1751 
1752         rcu_read_lock();
1753         ep = rcu_dereference(device->ldev->disk_conf)->on_io_error;
1754         rcu_read_unlock();
1755         switch (ep) {
1756         case EP_PASS_ON: /* FIXME would this be better named "Ignore"? */
1757                 if (df == DRBD_READ_ERROR || df == DRBD_WRITE_ERROR) {
1758                         if (__ratelimit(&drbd_ratelimit_state))
1759                                 drbd_err(device, "Local IO failed in %s.\n", where);
1760                         if (device->state.disk > D_INCONSISTENT)
1761                                 _drbd_set_state(_NS(device, disk, D_INCONSISTENT), CS_HARD, NULL);
1762                         break;
1763                 }
1764                 /* fall through - for DRBD_META_IO_ERROR or DRBD_FORCE_DETACH */
1765         case EP_DETACH:
1766         case EP_CALL_HELPER:
1767                 /* Remember whether we saw a READ or WRITE error.
1768                  *
1769                  * Recovery of the affected area for WRITE failure is covered
1770                  * by the activity log.
1771                  * READ errors may fall outside that area though. Certain READ
1772                  * errors can be "healed" by writing good data to the affected
1773                  * blocks, which triggers block re-allocation in lower layers.
1774                  *
1775                  * If we can not write the bitmap after a READ error,
1776                  * we may need to trigger a full sync (see w_go_diskless()).
1777                  *
1778                  * Force-detach is not really an IO error, but rather a
1779                  * desperate measure to try to deal with a completely
1780                  * unresponsive lower level IO stack.
1781                  * Still it should be treated as a WRITE error.
1782                  *
1783                  * Meta IO error is always WRITE error:
1784                  * we read meta data only once during attach,
1785                  * which will fail in case of errors.
1786                  */
1787                 set_bit(WAS_IO_ERROR, &device->flags);
1788                 if (df == DRBD_READ_ERROR)
1789                         set_bit(WAS_READ_ERROR, &device->flags);
1790                 if (df == DRBD_FORCE_DETACH)
1791                         set_bit(FORCE_DETACH, &device->flags);
1792                 if (device->state.disk > D_FAILED) {
1793                         _drbd_set_state(_NS(device, disk, D_FAILED), CS_HARD, NULL);
1794                         drbd_err(device,
1795                                 "Local IO failed in %s. Detaching...\n", where);
1796                 }
1797                 break;
1798         }
1799 }
1800 
1801 /**
1802  * drbd_chk_io_error: Handle the on_io_error setting, should be called from all io completion handlers
1803  * @device:      DRBD device.
1804  * @error:       Error code passed to the IO completion callback
1805  * @forcedetach: Force detach. I.e. the error happened while accessing the meta data
1806  *
1807  * See also drbd_main.c:after_state_ch() if (os.disk > D_FAILED && ns.disk == D_FAILED)
1808  */
1809 #define drbd_chk_io_error(m,e,f) drbd_chk_io_error_(m,e,f, __func__)
1810 static inline void drbd_chk_io_error_(struct drbd_device *device,
1811         int error, enum drbd_force_detach_flags forcedetach, const char *where)
1812 {
1813         if (error) {
1814                 unsigned long flags;
1815                 spin_lock_irqsave(&device->resource->req_lock, flags);
1816                 __drbd_chk_io_error_(device, forcedetach, where);
1817                 spin_unlock_irqrestore(&device->resource->req_lock, flags);
1818         }
1819 }
1820 
1821 
1822 /**
1823  * drbd_md_first_sector() - Returns the first sector number of the meta data area
1824  * @bdev:       Meta data block device.
1825  *
1826  * BTW, for internal meta data, this happens to be the maximum capacity
1827  * we could agree upon with our peer node.
1828  */
1829 static inline sector_t drbd_md_first_sector(struct drbd_backing_dev *bdev)
1830 {
1831         switch (bdev->md.meta_dev_idx) {
1832         case DRBD_MD_INDEX_INTERNAL:
1833         case DRBD_MD_INDEX_FLEX_INT:
1834                 return bdev->md.md_offset + bdev->md.bm_offset;
1835         case DRBD_MD_INDEX_FLEX_EXT:
1836         default:
1837                 return bdev->md.md_offset;
1838         }
1839 }
1840 
1841 /**
1842  * drbd_md_last_sector() - Return the last sector number of the meta data area
1843  * @bdev:       Meta data block device.
1844  */
1845 static inline sector_t drbd_md_last_sector(struct drbd_backing_dev *bdev)
1846 {
1847         switch (bdev->md.meta_dev_idx) {
1848         case DRBD_MD_INDEX_INTERNAL:
1849         case DRBD_MD_INDEX_FLEX_INT:
1850                 return bdev->md.md_offset + MD_4kB_SECT -1;
1851         case DRBD_MD_INDEX_FLEX_EXT:
1852         default:
1853                 return bdev->md.md_offset + bdev->md.md_size_sect -1;
1854         }
1855 }
1856 
1857 /* Returns the number of 512 byte sectors of the device */
1858 static inline sector_t drbd_get_capacity(struct block_device *bdev)
1859 {
1860         /* return bdev ? get_capacity(bdev->bd_disk) : 0; */
1861         return bdev ? i_size_read(bdev->bd_inode) >> 9 : 0;
1862 }
1863 
1864 /**
1865  * drbd_get_max_capacity() - Returns the capacity we announce to out peer
1866  * @bdev:       Meta data block device.
1867  *
1868  * returns the capacity we announce to out peer.  we clip ourselves at the
1869  * various MAX_SECTORS, because if we don't, current implementation will
1870  * oops sooner or later
1871  */
1872 static inline sector_t drbd_get_max_capacity(struct drbd_backing_dev *bdev)
1873 {
1874         sector_t s;
1875 
1876         switch (bdev->md.meta_dev_idx) {
1877         case DRBD_MD_INDEX_INTERNAL:
1878         case DRBD_MD_INDEX_FLEX_INT:
1879                 s = drbd_get_capacity(bdev->backing_bdev)
1880                         ? min_t(sector_t, DRBD_MAX_SECTORS_FLEX,
1881                                 drbd_md_first_sector(bdev))
1882                         : 0;
1883                 break;
1884         case DRBD_MD_INDEX_FLEX_EXT:
1885                 s = min_t(sector_t, DRBD_MAX_SECTORS_FLEX,
1886                                 drbd_get_capacity(bdev->backing_bdev));
1887                 /* clip at maximum size the meta device can support */
1888                 s = min_t(sector_t, s,
1889                         BM_EXT_TO_SECT(bdev->md.md_size_sect
1890                                      - bdev->md.bm_offset));
1891                 break;
1892         default:
1893                 s = min_t(sector_t, DRBD_MAX_SECTORS,
1894                                 drbd_get_capacity(bdev->backing_bdev));
1895         }
1896         return s;
1897 }
1898 
1899 /**
1900  * drbd_md_ss() - Return the sector number of our meta data super block
1901  * @bdev:       Meta data block device.
1902  */
1903 static inline sector_t drbd_md_ss(struct drbd_backing_dev *bdev)
1904 {
1905         const int meta_dev_idx = bdev->md.meta_dev_idx;
1906 
1907         if (meta_dev_idx == DRBD_MD_INDEX_FLEX_EXT)
1908                 return 0;
1909 
1910         /* Since drbd08, internal meta data is always "flexible".
1911          * position: last 4k aligned block of 4k size */
1912         if (meta_dev_idx == DRBD_MD_INDEX_INTERNAL ||
1913             meta_dev_idx == DRBD_MD_INDEX_FLEX_INT)
1914                 return (drbd_get_capacity(bdev->backing_bdev) & ~7ULL) - 8;
1915 
1916         /* external, some index; this is the old fixed size layout */
1917         return MD_128MB_SECT * bdev->md.meta_dev_idx;
1918 }
1919 
1920 static inline void
1921 drbd_queue_work(struct drbd_work_queue *q, struct drbd_work *w)
1922 {
1923         unsigned long flags;
1924         spin_lock_irqsave(&q->q_lock, flags);
1925         list_add_tail(&w->list, &q->q);
1926         spin_unlock_irqrestore(&q->q_lock, flags);
1927         wake_up(&q->q_wait);
1928 }
1929 
1930 static inline void
1931 drbd_queue_work_if_unqueued(struct drbd_work_queue *q, struct drbd_work *w)
1932 {
1933         unsigned long flags;
1934         spin_lock_irqsave(&q->q_lock, flags);
1935         if (list_empty_careful(&w->list))
1936                 list_add_tail(&w->list, &q->q);
1937         spin_unlock_irqrestore(&q->q_lock, flags);
1938         wake_up(&q->q_wait);
1939 }
1940 
1941 static inline void
1942 drbd_device_post_work(struct drbd_device *device, int work_bit)
1943 {
1944         if (!test_and_set_bit(work_bit, &device->flags)) {
1945                 struct drbd_connection *connection =
1946                         first_peer_device(device)->connection;
1947                 struct drbd_work_queue *q = &connection->sender_work;
1948                 if (!test_and_set_bit(DEVICE_WORK_PENDING, &connection->flags))
1949                         wake_up(&q->q_wait);
1950         }
1951 }
1952 
1953 extern void drbd_flush_workqueue(struct drbd_work_queue *work_queue);
1954 
1955 /* To get the ack_receiver out of the blocking network stack,
1956  * so it can change its sk_rcvtimeo from idle- to ping-timeout,
1957  * and send a ping, we need to send a signal.
1958  * Which signal we send is irrelevant. */
1959 static inline void wake_ack_receiver(struct drbd_connection *connection)
1960 {
1961         struct task_struct *task = connection->ack_receiver.task;
1962         if (task && get_t_state(&connection->ack_receiver) == RUNNING)
1963                 send_sig(SIGXCPU, task, 1);
1964 }
1965 
1966 static inline void request_ping(struct drbd_connection *connection)
1967 {
1968         set_bit(SEND_PING, &connection->flags);
1969         wake_ack_receiver(connection);
1970 }
1971 
1972 extern void *conn_prepare_command(struct drbd_connection *, struct drbd_socket *);
1973 extern void *drbd_prepare_command(struct drbd_peer_device *, struct drbd_socket *);
1974 extern int conn_send_command(struct drbd_connection *, struct drbd_socket *,
1975                              enum drbd_packet, unsigned int, void *,
1976                              unsigned int);
1977 extern int drbd_send_command(struct drbd_peer_device *, struct drbd_socket *,
1978                              enum drbd_packet, unsigned int, void *,
1979                              unsigned int);
1980 
1981 extern int drbd_send_ping(struct drbd_connection *connection);
1982 extern int drbd_send_ping_ack(struct drbd_connection *connection);
1983 extern int drbd_send_state_req(struct drbd_peer_device *, union drbd_state, union drbd_state);
1984 extern int conn_send_state_req(struct drbd_connection *, union drbd_state, union drbd_state);
1985 
1986 static inline void drbd_thread_stop(struct drbd_thread *thi)
1987 {
1988         _drbd_thread_stop(thi, false, true);
1989 }
1990 
1991 static inline void drbd_thread_stop_nowait(struct drbd_thread *thi)
1992 {
1993         _drbd_thread_stop(thi, false, false);
1994 }
1995 
1996 static inline void drbd_thread_restart_nowait(struct drbd_thread *thi)
1997 {
1998         _drbd_thread_stop(thi, true, false);
1999 }
2000 
2001 /* counts how many answer packets packets we expect from our peer,
2002  * for either explicit application requests,
2003  * or implicit barrier packets as necessary.
2004  * increased:
2005  *  w_send_barrier
2006  *  _req_mod(req, QUEUE_FOR_NET_WRITE or QUEUE_FOR_NET_READ);
2007  *    it is much easier and equally valid to count what we queue for the
2008  *    worker, even before it actually was queued or send.
2009  *    (drbd_make_request_common; recovery path on read io-error)
2010  * decreased:
2011  *  got_BarrierAck (respective tl_clear, tl_clear_barrier)
2012  *  _req_mod(req, DATA_RECEIVED)
2013  *     [from receive_DataReply]
2014  *  _req_mod(req, WRITE_ACKED_BY_PEER or RECV_ACKED_BY_PEER or NEG_ACKED)
2015  *     [from got_BlockAck (P_WRITE_ACK, P_RECV_ACK)]
2016  *     for some reason it is NOT decreased in got_NegAck,
2017  *     but in the resulting cleanup code from report_params.
2018  *     we should try to remember the reason for that...
2019  *  _req_mod(req, SEND_FAILED or SEND_CANCELED)
2020  *  _req_mod(req, CONNECTION_LOST_WHILE_PENDING)
2021  *     [from tl_clear_barrier]
2022  */
2023 static inline void inc_ap_pending(struct drbd_device *device)
2024 {
2025         atomic_inc(&device->ap_pending_cnt);
2026 }
2027 
2028 #define ERR_IF_CNT_IS_NEGATIVE(which, func, line)                       \
2029         if (atomic_read(&device->which) < 0)                            \
2030                 drbd_err(device, "in %s:%d: " #which " = %d < 0 !\n",   \
2031                         func, line,                                     \
2032                         atomic_read(&device->which))
2033 
2034 #define dec_ap_pending(device) _dec_ap_pending(device, __func__, __LINE__)
2035 static inline void _dec_ap_pending(struct drbd_device *device, const char *func, int line)
2036 {
2037         if (atomic_dec_and_test(&device->ap_pending_cnt))
2038                 wake_up(&device->misc_wait);
2039         ERR_IF_CNT_IS_NEGATIVE(ap_pending_cnt, func, line);
2040 }
2041 
2042 /* counts how many resync-related answers we still expect from the peer
2043  *                   increase                   decrease
2044  * C_SYNC_TARGET sends P_RS_DATA_REQUEST (and expects P_RS_DATA_REPLY)
2045  * C_SYNC_SOURCE sends P_RS_DATA_REPLY   (and expects P_WRITE_ACK with ID_SYNCER)
2046  *                                         (or P_NEG_ACK with ID_SYNCER)
2047  */
2048 static inline void inc_rs_pending(struct drbd_device *device)
2049 {
2050         atomic_inc(&device->rs_pending_cnt);
2051 }
2052 
2053 #define dec_rs_pending(device) _dec_rs_pending(device, __func__, __LINE__)
2054 static inline void _dec_rs_pending(struct drbd_device *device, const char *func, int line)
2055 {
2056         atomic_dec(&device->rs_pending_cnt);
2057         ERR_IF_CNT_IS_NEGATIVE(rs_pending_cnt, func, line);
2058 }
2059 
2060 /* counts how many answers we still need to send to the peer.
2061  * increased on
2062  *  receive_Data        unless protocol A;
2063  *                      we need to send a P_RECV_ACK (proto B)
2064  *                      or P_WRITE_ACK (proto C)
2065  *  receive_RSDataReply (recv_resync_read) we need to send a P_WRITE_ACK
2066  *  receive_DataRequest (receive_RSDataRequest) we need to send back P_DATA
2067  *  receive_Barrier_*   we need to send a P_BARRIER_ACK
2068  */
2069 static inline void inc_unacked(struct drbd_device *device)
2070 {
2071         atomic_inc(&device->unacked_cnt);
2072 }
2073 
2074 #define dec_unacked(device) _dec_unacked(device, __func__, __LINE__)
2075 static inline void _dec_unacked(struct drbd_device *device, const char *func, int line)
2076 {
2077         atomic_dec(&device->unacked_cnt);
2078         ERR_IF_CNT_IS_NEGATIVE(unacked_cnt, func, line);
2079 }
2080 
2081 #define sub_unacked(device, n) _sub_unacked(device, n, __func__, __LINE__)
2082 static inline void _sub_unacked(struct drbd_device *device, int n, const char *func, int line)
2083 {
2084         atomic_sub(n, &device->unacked_cnt);
2085         ERR_IF_CNT_IS_NEGATIVE(unacked_cnt, func, line);
2086 }
2087 
2088 static inline bool is_sync_target_state(enum drbd_conns connection_state)
2089 {
2090         return  connection_state == C_SYNC_TARGET ||
2091                 connection_state == C_PAUSED_SYNC_T;
2092 }
2093 
2094 static inline bool is_sync_source_state(enum drbd_conns connection_state)
2095 {
2096         return  connection_state == C_SYNC_SOURCE ||
2097                 connection_state == C_PAUSED_SYNC_S;
2098 }
2099 
2100 static inline bool is_sync_state(enum drbd_conns connection_state)
2101 {
2102         return  is_sync_source_state(connection_state) ||
2103                 is_sync_target_state(connection_state);
2104 }
2105 
2106 /**
2107  * get_ldev() - Increase the ref count on device->ldev. Returns 0 if there is no ldev
2108  * @_device:            DRBD device.
2109  * @_min_state:         Minimum device state required for success.
2110  *
2111  * You have to call put_ldev() when finished working with device->ldev.
2112  */
2113 #define get_ldev_if_state(_device, _min_state)                          \
2114         (_get_ldev_if_state((_device), (_min_state)) ?                  \
2115          ({ __acquire(x); true; }) : false)
2116 #define get_ldev(_device) get_ldev_if_state(_device, D_INCONSISTENT)
2117 
2118 static inline void put_ldev(struct drbd_device *device)
2119 {
2120         enum drbd_disk_state disk_state = device->state.disk;
2121         /* We must check the state *before* the atomic_dec becomes visible,
2122          * or we have a theoretical race where someone hitting zero,
2123          * while state still D_FAILED, will then see D_DISKLESS in the
2124          * condition below and calling into destroy, where he must not, yet. */
2125         int i = atomic_dec_return(&device->local_cnt);
2126 
2127         /* This may be called from some endio handler,
2128          * so we must not sleep here. */
2129 
2130         __release(local);
2131         D_ASSERT(device, i >= 0);
2132         if (i == 0) {
2133                 if (disk_state == D_DISKLESS)
2134                         /* even internal references gone, safe to destroy */
2135                         drbd_device_post_work(device, DESTROY_DISK);
2136                 if (disk_state == D_FAILED)
2137                         /* all application IO references gone. */
2138                         if (!test_and_set_bit(GOING_DISKLESS, &device->flags))
2139                                 drbd_device_post_work(device, GO_DISKLESS);
2140                 wake_up(&device->misc_wait);
2141         }
2142 }
2143 
2144 #ifndef __CHECKER__
2145 static inline int _get_ldev_if_state(struct drbd_device *device, enum drbd_disk_state mins)
2146 {
2147         int io_allowed;
2148 
2149         /* never get a reference while D_DISKLESS */
2150         if (device->state.disk == D_DISKLESS)
2151                 return 0;
2152 
2153         atomic_inc(&device->local_cnt);
2154         io_allowed = (device->state.disk >= mins);
2155         if (!io_allowed)
2156                 put_ldev(device);
2157         return io_allowed;
2158 }
2159 #else
2160 extern int _get_ldev_if_state(struct drbd_device *device, enum drbd_disk_state mins);
2161 #endif
2162 
2163 /* this throttles on-the-fly application requests
2164  * according to max_buffers settings;
2165  * maybe re-implement using semaphores? */
2166 static inline int drbd_get_max_buffers(struct drbd_device *device)
2167 {
2168         struct net_conf *nc;
2169         int mxb;
2170 
2171         rcu_read_lock();
2172         nc = rcu_dereference(first_peer_device(device)->connection->net_conf);
2173         mxb = nc ? nc->max_buffers : 1000000;  /* arbitrary limit on open requests */
2174         rcu_read_unlock();
2175 
2176         return mxb;
2177 }
2178 
2179 static inline int drbd_state_is_stable(struct drbd_device *device)
2180 {
2181         union drbd_dev_state s = device->state;
2182 
2183         /* DO NOT add a default clause, we want the compiler to warn us
2184          * for any newly introduced state we may have forgotten to add here */
2185 
2186         switch ((enum drbd_conns)s.conn) {
2187         /* new io only accepted when there is no connection, ... */
2188         case C_STANDALONE:
2189         case C_WF_CONNECTION:
2190         /* ... or there is a well established connection. */
2191         case C_CONNECTED:
2192         case C_SYNC_SOURCE:
2193         case C_SYNC_TARGET:
2194         case C_VERIFY_S:
2195         case C_VERIFY_T:
2196         case C_PAUSED_SYNC_S:
2197         case C_PAUSED_SYNC_T:
2198         case C_AHEAD:
2199         case C_BEHIND:
2200                 /* transitional states, IO allowed */
2201         case C_DISCONNECTING:
2202         case C_UNCONNECTED:
2203         case C_TIMEOUT:
2204         case C_BROKEN_PIPE:
2205         case C_NETWORK_FAILURE:
2206         case C_PROTOCOL_ERROR:
2207         case C_TEAR_DOWN:
2208         case C_WF_REPORT_PARAMS:
2209         case C_STARTING_SYNC_S:
2210         case C_STARTING_SYNC_T:
2211                 break;
2212 
2213                 /* Allow IO in BM exchange states with new protocols */
2214         case C_WF_BITMAP_S:
2215                 if (first_peer_device(device)->connection->agreed_pro_version < 96)
2216                         return 0;
2217                 break;
2218 
2219                 /* no new io accepted in these states */
2220         case C_WF_BITMAP_T:
2221         case C_WF_SYNC_UUID:
2222         case C_MASK:
2223                 /* not "stable" */
2224                 return 0;
2225         }
2226 
2227         switch ((enum drbd_disk_state)s.disk) {
2228         case D_DISKLESS:
2229         case D_INCONSISTENT:
2230         case D_OUTDATED:
2231         case D_CONSISTENT:
2232         case D_UP_TO_DATE:
2233         case D_FAILED:
2234                 /* disk state is stable as well. */
2235                 break;
2236 
2237         /* no new io accepted during transitional states */
2238         case D_ATTACHING:
2239         case D_NEGOTIATING:
2240         case D_UNKNOWN:
2241         case D_MASK:
2242                 /* not "stable" */
2243                 return 0;
2244         }
2245 
2246         return 1;
2247 }
2248 
2249 static inline int drbd_suspended(struct drbd_device *device)
2250 {
2251         struct drbd_resource *resource = device->resource;
2252 
2253         return resource->susp || resource->susp_fen || resource->susp_nod;
2254 }
2255 
2256 static inline bool may_inc_ap_bio(struct drbd_device *device)
2257 {
2258         int mxb = drbd_get_max_buffers(device);
2259 
2260         if (drbd_suspended(device))
2261                 return false;
2262         if (atomic_read(&device->suspend_cnt))
2263                 return false;
2264 
2265         /* to avoid potential deadlock or bitmap corruption,
2266          * in various places, we only allow new application io
2267          * to start during "stable" states. */
2268 
2269         /* no new io accepted when attaching or detaching the disk */
2270         if (!drbd_state_is_stable(device))
2271                 return false;
2272 
2273         /* since some older kernels don't have atomic_add_unless,
2274          * and we are within the spinlock anyways, we have this workaround.  */
2275         if (atomic_read(&device->ap_bio_cnt) > mxb)
2276                 return false;
2277         if (test_bit(BITMAP_IO, &device->flags))
2278                 return false;
2279         return true;
2280 }
2281 
2282 static inline bool inc_ap_bio_cond(struct drbd_device *device)
2283 {
2284         bool rv = false;
2285 
2286         spin_lock_irq(&device->resource->req_lock);
2287         rv = may_inc_ap_bio(device);
2288         if (rv)
2289                 atomic_inc(&device->ap_bio_cnt);
2290         spin_unlock_irq(&device->resource->req_lock);
2291 
2292         return rv;
2293 }
2294 
2295 static inline void inc_ap_bio(struct drbd_device *device)
2296 {
2297         /* we wait here
2298          *    as long as the device is suspended
2299          *    until the bitmap is no longer on the fly during connection
2300          *    handshake as long as we would exceed the max_buffer limit.
2301          *
2302          * to avoid races with the reconnect code,
2303          * we need to atomic_inc within the spinlock. */
2304 
2305         wait_event(device->misc_wait, inc_ap_bio_cond(device));
2306 }
2307 
2308 static inline void dec_ap_bio(struct drbd_device *device)
2309 {
2310         int mxb = drbd_get_max_buffers(device);
2311         int ap_bio = atomic_dec_return(&device->ap_bio_cnt);
2312 
2313         D_ASSERT(device, ap_bio >= 0);
2314 
2315         if (ap_bio == 0 && test_bit(BITMAP_IO, &device->flags)) {
2316                 if (!test_and_set_bit(BITMAP_IO_QUEUED, &device->flags))
2317                         drbd_queue_work(&first_peer_device(device)->
2318                                 connection->sender_work,
2319                                 &device->bm_io_work.w);
2320         }
2321 
2322         /* this currently does wake_up for every dec_ap_bio!
2323          * maybe rather introduce some type of hysteresis?
2324          * e.g. (ap_bio == mxb/2 || ap_bio == 0) ? */
2325         if (ap_bio < mxb)
2326                 wake_up(&device->misc_wait);
2327 }
2328 
2329 static inline bool verify_can_do_stop_sector(struct drbd_device *device)
2330 {
2331         return first_peer_device(device)->connection->agreed_pro_version >= 97 &&
2332                 first_peer_device(device)->connection->agreed_pro_version != 100;
2333 }
2334 
2335 static inline int drbd_set_ed_uuid(struct drbd_device *device, u64 val)
2336 {
2337         int changed = device->ed_uuid != val;
2338         device->ed_uuid = val;
2339         return changed;
2340 }
2341 
2342 static inline int drbd_queue_order_type(struct drbd_device *device)
2343 {
2344         /* sorry, we currently have no working implementation
2345          * of distributed TCQ stuff */
2346 #ifndef QUEUE_ORDERED_NONE
2347 #define QUEUE_ORDERED_NONE 0
2348 #endif
2349         return QUEUE_ORDERED_NONE;
2350 }
2351 
2352 static inline struct drbd_connection *first_connection(struct drbd_resource *resource)
2353 {
2354         return list_first_entry_or_null(&resource->connections,
2355                                 struct drbd_connection, connections);
2356 }
2357 
2358 #endif