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