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