1 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
2 /*
3 md_p.h : physical layout of Linux RAID devices
4 Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 You should have received a copy of the GNU General Public License
12 (for example /usr/src/linux/COPYING); if not, write to the Free
13 Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
14 */
15
16 #ifndef _MD_P_H
17 #define _MD_P_H
18
19 #include <linux/types.h>
20 #include <asm/byteorder.h>
21
22 /*
23 * RAID superblock.
24 *
25 * The RAID superblock maintains some statistics on each RAID configuration.
26 * Each real device in the RAID set contains it near the end of the device.
27 * Some of the ideas are copied from the ext2fs implementation.
28 *
29 * We currently use 4096 bytes as follows:
30 *
31 * word offset function
32 *
33 * 0 - 31 Constant generic RAID device information.
34 * 32 - 63 Generic state information.
35 * 64 - 127 Personality specific information.
36 * 128 - 511 12 32-words descriptors of the disks in the raid set.
37 * 512 - 911 Reserved.
38 * 912 - 1023 Disk specific descriptor.
39 */
40
41 /*
42 * If x is the real device size in bytes, we return an apparent size of:
43 *
44 * y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES
45 *
46 * and place the 4kB superblock at offset y.
47 */
48 #define MD_RESERVED_BYTES (64 * 1024)
49 #define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512)
50
51 #define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS)
52
53 #define MD_SB_BYTES 4096
54 #define MD_SB_WORDS (MD_SB_BYTES / 4)
55 #define MD_SB_SECTORS (MD_SB_BYTES / 512)
56
57 /*
58 * The following are counted in 32-bit words
59 */
60 #define MD_SB_GENERIC_OFFSET 0
61 #define MD_SB_PERSONALITY_OFFSET 64
62 #define MD_SB_DISKS_OFFSET 128
63 #define MD_SB_DESCRIPTOR_OFFSET 992
64
65 #define MD_SB_GENERIC_CONSTANT_WORDS 32
66 #define MD_SB_GENERIC_STATE_WORDS 32
67 #define MD_SB_GENERIC_WORDS (MD_SB_GENERIC_CONSTANT_WORDS + MD_SB_GENERIC_STATE_WORDS)
68 #define MD_SB_PERSONALITY_WORDS 64
69 #define MD_SB_DESCRIPTOR_WORDS 32
70 #define MD_SB_DISKS 27
71 #define MD_SB_DISKS_WORDS (MD_SB_DISKS*MD_SB_DESCRIPTOR_WORDS)
72 #define MD_SB_RESERVED_WORDS (1024 - MD_SB_GENERIC_WORDS - MD_SB_PERSONALITY_WORDS - MD_SB_DISKS_WORDS - MD_SB_DESCRIPTOR_WORDS)
73 #define MD_SB_EQUAL_WORDS (MD_SB_GENERIC_WORDS + MD_SB_PERSONALITY_WORDS + MD_SB_DISKS_WORDS)
74
75 /*
76 * Device "operational" state bits
77 */
78 #define MD_DISK_FAULTY 0 /* disk is faulty / operational */
79 #define MD_DISK_ACTIVE 1 /* disk is running or spare disk */
80 #define MD_DISK_SYNC 2 /* disk is in sync with the raid set */
81 #define MD_DISK_REMOVED 3 /* disk is in sync with the raid set */
82 #define MD_DISK_CLUSTER_ADD 4 /* Initiate a disk add across the cluster
83 * For clustered enviroments only.
84 */
85 #define MD_DISK_CANDIDATE 5 /* disk is added as spare (local) until confirmed
86 * For clustered enviroments only.
87 */
88 #define MD_DISK_FAILFAST 10 /* Send REQ_FAILFAST if there are multiple
89 * devices available - and don't try to
90 * correct read errors.
91 */
92
93 #define MD_DISK_WRITEMOSTLY 9 /* disk is "write-mostly" is RAID1 config.
94 * read requests will only be sent here in
95 * dire need
96 */
97 #define MD_DISK_JOURNAL 18 /* disk is used as the write journal in RAID-5/6 */
98
99 #define MD_DISK_ROLE_SPARE 0xffff
100 #define MD_DISK_ROLE_FAULTY 0xfffe
101 #define MD_DISK_ROLE_JOURNAL 0xfffd
102 #define MD_DISK_ROLE_MAX 0xff00 /* max value of regular disk role */
103
104 typedef struct mdp_device_descriptor_s {
105 __u32 number; /* 0 Device number in the entire set */
106 __u32 major; /* 1 Device major number */
107 __u32 minor; /* 2 Device minor number */
108 __u32 raid_disk; /* 3 The role of the device in the raid set */
109 __u32 state; /* 4 Operational state */
110 __u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5];
111 } mdp_disk_t;
112
113 #define MD_SB_MAGIC 0xa92b4efc
114
115 /*
116 * Superblock state bits
117 */
118 #define MD_SB_CLEAN 0
119 #define MD_SB_ERRORS 1
120
121 #define MD_SB_CLUSTERED 5 /* MD is clustered */
122 #define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */
123
124 /*
125 * Notes:
126 * - if an array is being reshaped (restriped) in order to change the
127 * the number of active devices in the array, 'raid_disks' will be
128 * the larger of the old and new numbers. 'delta_disks' will
129 * be the "new - old". So if +ve, raid_disks is the new value, and
130 * "raid_disks-delta_disks" is the old. If -ve, raid_disks is the
131 * old value and "raid_disks+delta_disks" is the new (smaller) value.
132 */
133
134
135 typedef struct mdp_superblock_s {
136 /*
137 * Constant generic information
138 */
139 __u32 md_magic; /* 0 MD identifier */
140 __u32 major_version; /* 1 major version to which the set conforms */
141 __u32 minor_version; /* 2 minor version ... */
142 __u32 patch_version; /* 3 patchlevel version ... */
143 __u32 gvalid_words; /* 4 Number of used words in this section */
144 __u32 set_uuid0; /* 5 Raid set identifier */
145 __u32 ctime; /* 6 Creation time */
146 __u32 level; /* 7 Raid personality */
147 __u32 size; /* 8 Apparent size of each individual disk */
148 __u32 nr_disks; /* 9 total disks in the raid set */
149 __u32 raid_disks; /* 10 disks in a fully functional raid set */
150 __u32 md_minor; /* 11 preferred MD minor device number */
151 __u32 not_persistent; /* 12 does it have a persistent superblock */
152 __u32 set_uuid1; /* 13 Raid set identifier #2 */
153 __u32 set_uuid2; /* 14 Raid set identifier #3 */
154 __u32 set_uuid3; /* 15 Raid set identifier #4 */
155 __u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16];
156
157 /*
158 * Generic state information
159 */
160 __u32 utime; /* 0 Superblock update time */
161 __u32 state; /* 1 State bits (clean, ...) */
162 __u32 active_disks; /* 2 Number of currently active disks */
163 __u32 working_disks; /* 3 Number of working disks */
164 __u32 failed_disks; /* 4 Number of failed disks */
165 __u32 spare_disks; /* 5 Number of spare disks */
166 __u32 sb_csum; /* 6 checksum of the whole superblock */
167 #if defined(__BYTE_ORDER) ? __BYTE_ORDER == __BIG_ENDIAN : defined(__BIG_ENDIAN)
168 __u32 events_hi; /* 7 high-order of superblock update count */
169 __u32 events_lo; /* 8 low-order of superblock update count */
170 __u32 cp_events_hi; /* 9 high-order of checkpoint update count */
171 __u32 cp_events_lo; /* 10 low-order of checkpoint update count */
172 #elif defined(__BYTE_ORDER) ? __BYTE_ORDER == __LITTLE_ENDIAN : defined(__LITTLE_ENDIAN)
173 __u32 events_lo; /* 7 low-order of superblock update count */
174 __u32 events_hi; /* 8 high-order of superblock update count */
175 __u32 cp_events_lo; /* 9 low-order of checkpoint update count */
176 __u32 cp_events_hi; /* 10 high-order of checkpoint update count */
177 #else
178 #error unspecified endianness
179 #endif
180 __u32 recovery_cp; /* 11 recovery checkpoint sector count */
181 /* There are only valid for minor_version > 90 */
182 __u64 reshape_position; /* 12,13 next address in array-space for reshape */
183 __u32 new_level; /* 14 new level we are reshaping to */
184 __u32 delta_disks; /* 15 change in number of raid_disks */
185 __u32 new_layout; /* 16 new layout */
186 __u32 new_chunk; /* 17 new chunk size (bytes) */
187 __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 18];
188
189 /*
190 * Personality information
191 */
192 __u32 layout; /* 0 the array's physical layout */
193 __u32 chunk_size; /* 1 chunk size in bytes */
194 __u32 root_pv; /* 2 LV root PV */
195 __u32 root_block; /* 3 LV root block */
196 __u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4];
197
198 /*
199 * Disks information
200 */
201 mdp_disk_t disks[MD_SB_DISKS];
202
203 /*
204 * Reserved
205 */
206 __u32 reserved[MD_SB_RESERVED_WORDS];
207
208 /*
209 * Active descriptor
210 */
211 mdp_disk_t this_disk;
212
213 } mdp_super_t;
214
215 static inline __u64 md_event(mdp_super_t *sb) {
216 __u64 ev = sb->events_hi;
217 return (ev<<32)| sb->events_lo;
218 }
219
220 #define MD_SUPERBLOCK_1_TIME_SEC_MASK ((1ULL<<40) - 1)
221
222 /*
223 * The version-1 superblock :
224 * All numeric fields are little-endian.
225 *
226 * total size: 256 bytes plus 2 per device.
227 * 1K allows 384 devices.
228 */
229 struct mdp_superblock_1 {
230 /* constant array information - 128 bytes */
231 __le32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */
232 __le32 major_version; /* 1 */
233 __le32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */
234 __le32 pad0; /* always set to 0 when writing */
235
236 __u8 set_uuid[16]; /* user-space generated. */
237 char set_name[32]; /* set and interpreted by user-space */
238
239 __le64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/
240 __le32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */
241 __le32 layout; /* only for raid5 and raid10 currently */
242 __le64 size; /* used size of component devices, in 512byte sectors */
243
244 __le32 chunksize; /* in 512byte sectors */
245 __le32 raid_disks;
246 union {
247 __le32 bitmap_offset; /* sectors after start of superblock that bitmap starts
248 * NOTE: signed, so bitmap can be before superblock
249 * only meaningful of feature_map[0] is set.
250 */
251
252 /* only meaningful when feature_map[MD_FEATURE_PPL] is set */
253 struct {
254 __le16 offset; /* sectors from start of superblock that ppl starts (signed) */
255 __le16 size; /* ppl size in sectors */
256 } ppl;
257 };
258
259 /* These are only valid with feature bit '4' */
260 __le32 new_level; /* new level we are reshaping to */
261 __le64 reshape_position; /* next address in array-space for reshape */
262 __le32 delta_disks; /* change in number of raid_disks */
263 __le32 new_layout; /* new layout */
264 __le32 new_chunk; /* new chunk size (512byte sectors) */
265 __le32 new_offset; /* signed number to add to data_offset in new
266 * layout. 0 == no-change. This can be
267 * different on each device in the array.
268 */
269
270 /* constant this-device information - 64 bytes */
271 __le64 data_offset; /* sector start of data, often 0 */
272 __le64 data_size; /* sectors in this device that can be used for data */
273 __le64 super_offset; /* sector start of this superblock */
274 union {
275 __le64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */
276 __le64 journal_tail;/* journal tail of journal device (from data_offset) */
277 };
278 __le32 dev_number; /* permanent identifier of this device - not role in raid */
279 __le32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */
280 __u8 device_uuid[16]; /* user-space setable, ignored by kernel */
281 __u8 devflags; /* per-device flags. Only two defined...*/
282 #define WriteMostly1 1 /* mask for writemostly flag in above */
283 #define FailFast1 2 /* Should avoid retries and fixups and just fail */
284 /* Bad block log. If there are any bad blocks the feature flag is set.
285 * If offset and size are non-zero, that space is reserved and available
286 */
287 __u8 bblog_shift; /* shift from sectors to block size */
288 __le16 bblog_size; /* number of sectors reserved for list */
289 __le32 bblog_offset; /* sector offset from superblock to bblog,
290 * signed - not unsigned */
291
292 /* array state information - 64 bytes */
293 __le64 utime; /* 40 bits second, 24 bits microseconds */
294 __le64 events; /* incremented when superblock updated */
295 __le64 resync_offset; /* data before this offset (from data_offset) known to be in sync */
296 __le32 sb_csum; /* checksum up to devs[max_dev] */
297 __le32 max_dev; /* size of devs[] array to consider */
298 __u8 pad3[64-32]; /* set to 0 when writing */
299
300 /* device state information. Indexed by dev_number.
301 * 2 bytes per device
302 * Note there are no per-device state flags. State information is rolled
303 * into the 'roles' value. If a device is spare or faulty, then it doesn't
304 * have a meaningful role.
305 */
306 __le16 dev_roles[0]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */
307 };
308
309 /* feature_map bits */
310 #define MD_FEATURE_BITMAP_OFFSET 1
311 #define MD_FEATURE_RECOVERY_OFFSET 2 /* recovery_offset is present and
312 * must be honoured
313 */
314 #define MD_FEATURE_RESHAPE_ACTIVE 4
315 #define MD_FEATURE_BAD_BLOCKS 8 /* badblock list is not empty */
316 #define MD_FEATURE_REPLACEMENT 16 /* This device is replacing an
317 * active device with same 'role'.
318 * 'recovery_offset' is also set.
319 */
320 #define MD_FEATURE_RESHAPE_BACKWARDS 32 /* Reshape doesn't change number
321 * of devices, but is going
322 * backwards anyway.
323 */
324 #define MD_FEATURE_NEW_OFFSET 64 /* new_offset must be honoured */
325 #define MD_FEATURE_RECOVERY_BITMAP 128 /* recovery that is happening
326 * is guided by bitmap.
327 */
328 #define MD_FEATURE_CLUSTERED 256 /* clustered MD */
329 #define MD_FEATURE_JOURNAL 512 /* support write cache */
330 #define MD_FEATURE_PPL 1024 /* support PPL */
331 #define MD_FEATURE_MULTIPLE_PPLS 2048 /* support for multiple PPLs */
332 #define MD_FEATURE_RAID0_LAYOUT 4096 /* layout is meaningful for RAID0 */
333 #define MD_FEATURE_ALL (MD_FEATURE_BITMAP_OFFSET \
334 |MD_FEATURE_RECOVERY_OFFSET \
335 |MD_FEATURE_RESHAPE_ACTIVE \
336 |MD_FEATURE_BAD_BLOCKS \
337 |MD_FEATURE_REPLACEMENT \
338 |MD_FEATURE_RESHAPE_BACKWARDS \
339 |MD_FEATURE_NEW_OFFSET \
340 |MD_FEATURE_RECOVERY_BITMAP \
341 |MD_FEATURE_CLUSTERED \
342 |MD_FEATURE_JOURNAL \
343 |MD_FEATURE_PPL \
344 |MD_FEATURE_MULTIPLE_PPLS \
345 |MD_FEATURE_RAID0_LAYOUT \
346 )
347
348 struct r5l_payload_header {
349 __le16 type;
350 __le16 flags;
351 } __attribute__ ((__packed__));
352
353 enum r5l_payload_type {
354 R5LOG_PAYLOAD_DATA = 0,
355 R5LOG_PAYLOAD_PARITY = 1,
356 R5LOG_PAYLOAD_FLUSH = 2,
357 };
358
359 struct r5l_payload_data_parity {
360 struct r5l_payload_header header;
361 __le32 size; /* sector. data/parity size. each 4k
362 * has a checksum */
363 __le64 location; /* sector. For data, it's raid sector. For
364 * parity, it's stripe sector */
365 __le32 checksum[];
366 } __attribute__ ((__packed__));
367
368 enum r5l_payload_data_parity_flag {
369 R5LOG_PAYLOAD_FLAG_DISCARD = 1, /* payload is discard */
370 /*
371 * RESHAPED/RESHAPING is only set when there is reshape activity. Note,
372 * both data/parity of a stripe should have the same flag set
373 *
374 * RESHAPED: reshape is running, and this stripe finished reshape
375 * RESHAPING: reshape is running, and this stripe isn't reshaped
376 */
377 R5LOG_PAYLOAD_FLAG_RESHAPED = 2,
378 R5LOG_PAYLOAD_FLAG_RESHAPING = 3,
379 };
380
381 struct r5l_payload_flush {
382 struct r5l_payload_header header;
383 __le32 size; /* flush_stripes size, bytes */
384 __le64 flush_stripes[];
385 } __attribute__ ((__packed__));
386
387 enum r5l_payload_flush_flag {
388 R5LOG_PAYLOAD_FLAG_FLUSH_STRIPE = 1, /* data represents whole stripe */
389 };
390
391 struct r5l_meta_block {
392 __le32 magic;
393 __le32 checksum;
394 __u8 version;
395 __u8 __zero_pading_1;
396 __le16 __zero_pading_2;
397 __le32 meta_size; /* whole size of the block */
398
399 __le64 seq;
400 __le64 position; /* sector, start from rdev->data_offset, current position */
401 struct r5l_payload_header payloads[];
402 } __attribute__ ((__packed__));
403
404 #define R5LOG_VERSION 0x1
405 #define R5LOG_MAGIC 0x6433c509
406
407 struct ppl_header_entry {
408 __le64 data_sector; /* raid sector of the new data */
409 __le32 pp_size; /* length of partial parity */
410 __le32 data_size; /* length of data */
411 __le32 parity_disk; /* member disk containing parity */
412 __le32 checksum; /* checksum of partial parity data for this
413 * entry (~crc32c) */
414 } __attribute__ ((__packed__));
415
416 #define PPL_HEADER_SIZE 4096
417 #define PPL_HDR_RESERVED 512
418 #define PPL_HDR_ENTRY_SPACE \
419 (PPL_HEADER_SIZE - PPL_HDR_RESERVED - 4 * sizeof(__le32) - sizeof(__le64))
420 #define PPL_HDR_MAX_ENTRIES \
421 (PPL_HDR_ENTRY_SPACE / sizeof(struct ppl_header_entry))
422
423 struct ppl_header {
424 __u8 reserved[PPL_HDR_RESERVED];/* reserved space, fill with 0xff */
425 __le32 signature; /* signature (family number of volume) */
426 __le32 padding; /* zero pad */
427 __le64 generation; /* generation number of the header */
428 __le32 entries_count; /* number of entries in entry array */
429 __le32 checksum; /* checksum of the header (~crc32c) */
430 struct ppl_header_entry entries[PPL_HDR_MAX_ENTRIES];
431 } __attribute__ ((__packed__));
432
433 #endif