2 md_p.h : physical layout of Linux RAID devices
3 Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
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)
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.
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.
25 * We currently use 4096 bytes as follows:
27 * word offset function
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.
34 * 912 - 1023 Disk specific descriptor.
38 * If x is the real device size in bytes, we return an apparent size of:
40 * y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES
42 * and place the 4kB superblock at offset y.
44 #define MD_RESERVED_BYTES (64 * 1024)
45 #define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512)
46 #define MD_RESERVED_BLOCKS (MD_RESERVED_BYTES / BLOCK_SIZE)
48 #define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS)
49 #define MD_NEW_SIZE_BLOCKS(x) ((x & ~(MD_RESERVED_BLOCKS - 1)) - MD_RESERVED_BLOCKS)
51 #define MD_SB_BYTES 4096
52 #define MD_SB_WORDS (MD_SB_BYTES / 4)
53 #define MD_SB_BLOCKS (MD_SB_BYTES / BLOCK_SIZE)
54 #define MD_SB_SECTORS (MD_SB_BYTES / 512)
57 * The following are counted in 32-bit words
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
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)
75 * Device "operational" state bits
77 #define MD_DISK_FAULTY 0 /* disk is faulty / operational */
78 #define MD_DISK_ACTIVE 1 /* disk is running but may not be in sync */
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.
84 #define MD_DISK_CANDIDATE 5 /* disk is added as spare (local) until confirmed
85 * For clustered enviroments only.
88 #define MD_DISK_WRITEMOSTLY 9 /* disk is "write-mostly" is RAID1 config.
89 * read requests will only be sent here in
92 #define MD_DISK_FAILFAST 10 /* Fewer retries, more failures */
94 #define MD_DISK_REPLACEMENT 17
95 #define MD_DISK_JOURNAL 18 /* disk is used as the write journal in RAID-5/6 */
97 #define MD_DISK_ROLE_SPARE 0xffff
98 #define MD_DISK_ROLE_FAULTY 0xfffe
99 #define MD_DISK_ROLE_JOURNAL 0xfffd
100 #define MD_DISK_ROLE_MAX 0xff00 /* max value of regular disk role */
102 typedef struct mdp_device_descriptor_s
{
103 __u32 number
; /* 0 Device number in the entire set */
104 __u32 major
; /* 1 Device major number */
105 __u32 minor
; /* 2 Device minor number */
106 __u32 raid_disk
; /* 3 The role of the device in the raid set */
107 __u32 state
; /* 4 Operational state */
108 __u32 reserved
[MD_SB_DESCRIPTOR_WORDS
- 5];
111 #define MD_SB_MAGIC 0xa92b4efc
114 * Superblock state bits
116 #define MD_SB_CLEAN 0
117 #define MD_SB_ERRORS 1
118 #define MD_SB_BBM_ERRORS 2
119 #define MD_SB_BLOCK_CONTAINER_RESHAPE 3 /* block container wide reshapes */
120 #define MD_SB_BLOCK_VOLUME 4 /* block activation of array, other arrays
121 * in container can be activated */
122 #define MD_SB_CLUSTERED 5 /* MD is clustered */
123 #define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */
125 typedef struct mdp_superblock_s
{
127 * Constant generic information
129 __u32 md_magic
; /* 0 MD identifier */
130 __u32 major_version
; /* 1 major version to which the set conforms */
131 __u32 minor_version
; /* 2 minor version ... */
132 __u32 patch_version
; /* 3 patchlevel version ... */
133 __u32 gvalid_words
; /* 4 Number of used words in this section */
134 __u32 set_uuid0
; /* 5 Raid set identifier */
135 __u32 ctime
; /* 6 Creation time */
136 __u32 level
; /* 7 Raid personality */
137 __u32 size
; /* 8 Apparent size of each individual disk */
138 __u32 nr_disks
; /* 9 total disks in the raid set */
139 __u32 raid_disks
; /* 10 disks in a fully functional raid set */
140 __u32 md_minor
; /* 11 preferred MD minor device number */
141 __u32 not_persistent
; /* 12 does it have a persistent superblock */
142 __u32 set_uuid1
; /* 13 Raid set identifier #2 */
143 __u32 set_uuid2
; /* 14 Raid set identifier #3 */
144 __u32 set_uuid3
; /* 15 Raid set identifier #4 */
145 __u32 gstate_creserved
[MD_SB_GENERIC_CONSTANT_WORDS
- 16];
148 * Generic state information
150 __u32 utime
; /* 0 Superblock update time */
151 __u32 state
; /* 1 State bits (clean, ...) */
152 __u32 active_disks
; /* 2 Number of currently active disks */
153 __u32 working_disks
; /* 3 Number of working disks */
154 __u32 failed_disks
; /* 4 Number of failed disks */
155 __u32 spare_disks
; /* 5 Number of spare disks */
156 __u32 sb_csum
; /* 6 checksum of the whole superblock */
157 #if __BYTE_ORDER == __BIG_ENDIAN
158 __u32 events_hi
; /* 7 high-order of superblock update count */
159 __u32 events_lo
; /* 8 low-order of superblock update count */
160 __u32 cp_events_hi
; /* 9 high-order of checkpoint update count */
161 __u32 cp_events_lo
; /* 10 low-order of checkpoint update count */
163 __u32 events_lo
; /* 7 low-order of superblock update count */
164 __u32 events_hi
; /* 8 high-order of superblock update count */
165 __u32 cp_events_lo
; /* 9 low-order of checkpoint update count */
166 __u32 cp_events_hi
; /* 10 high-order of checkpoint update count */
168 __u32 recovery_cp
; /* 11 recovery checkpoint sector count */
169 /* There are only valid for minor_version > 90 */
170 __u64 reshape_position
; /* 12,13 next address in array-space for reshape */
171 __u32 new_level
; /* 14 new level we are reshaping to */
172 __u32 delta_disks
; /* 15 change in number of raid_disks */
173 __u32 new_layout
; /* 16 new layout */
174 __u32 new_chunk
; /* 17 new chunk size (bytes) */
175 __u32 gstate_sreserved
[MD_SB_GENERIC_STATE_WORDS
- 18];
178 * Personality information
180 __u32 layout
; /* 0 the array's physical layout */
181 __u32 chunk_size
; /* 1 chunk size in bytes */
182 __u32 root_pv
; /* 2 LV root PV */
183 __u32 root_block
; /* 3 LV root block */
184 __u32 pstate_reserved
[MD_SB_PERSONALITY_WORDS
- 4];
189 mdp_disk_t disks
[MD_SB_DISKS
];
194 __u32 reserved
[MD_SB_RESERVED_WORDS
];
199 mdp_disk_t this_disk
;
204 typedef unsigned long long __u64
;
207 static inline __u64
md_event(mdp_super_t
*sb
) {
208 __u64 ev
= sb
->events_hi
;
209 return (ev
<<32)| sb
->events_lo
;
212 struct r5l_payload_header
{
215 } __attribute__ ((__packed__
));
217 enum r5l_payload_type
{
218 R5LOG_PAYLOAD_DATA
= 0,
219 R5LOG_PAYLOAD_PARITY
= 1,
220 R5LOG_PAYLOAD_FLUSH
= 2,
223 struct r5l_payload_data_parity
{
224 struct r5l_payload_header header
;
225 __u32 size
; /* sector. data/parity size. each 4k has a checksum */
226 __u64 location
; /* sector. For data, it's raid sector. For
227 parity, it's stripe sector */
229 } __attribute__ ((__packed__
));
231 enum r5l_payload_data_parity_flag
{
232 R5LOG_PAYLOAD_FLAG_DISCARD
= 1, /* payload is discard */
234 * RESHAPED/RESHAPING is only set when there is reshape activity. Note,
235 * both data/parity of a stripe should have the same flag set
237 * RESHAPED: reshape is running, and this stripe finished reshape
238 * RESHAPING: reshape is running, and this stripe isn't reshaped
240 R5LOG_PAYLOAD_FLAG_RESHAPED
= 2,
241 R5LOG_PAYLOAD_FLAG_RESHAPING
= 3,
244 struct r5l_payload_flush
{
245 struct r5l_payload_header header
;
246 __u32 size
; /* flush_stripes size, bytes */
247 __u64 flush_stripes
[];
248 } __attribute__ ((__packed__
));
250 enum r5l_payload_flush_flag
{
251 R5LOG_PAYLOAD_FLAG_FLUSH_STRIPE
= 1, /* data represents whole stripe */
254 struct r5l_meta_block
{
258 __u8 __zero_pading_1
;
259 __u16 __zero_pading_2
;
260 __u32 meta_size
; /* whole size of the block */
263 __u64 position
; /* sector, start from rdev->data_offset, current position */
264 struct r5l_payload_header payloads
[];
265 } __attribute__ ((__packed__
));
267 #define R5LOG_VERSION 0x1
268 #define R5LOG_MAGIC 0x6433c509
270 struct ppl_header_entry
{
271 __u64 data_sector
; /* raid sector of the new data */
272 __u32 pp_size
; /* length of partial parity */
273 __u32 data_size
; /* length of data */
274 __u32 parity_disk
; /* member disk containing parity */
275 __u32 checksum
; /* checksum of this entry's partial parity */
276 } __attribute__ ((__packed__
));
278 #define PPL_HEADER_SIZE 4096
279 #define PPL_HDR_RESERVED 512
280 #define PPL_HDR_ENTRY_SPACE \
281 (PPL_HEADER_SIZE - PPL_HDR_RESERVED - 4 * sizeof(__u32) - sizeof(__u64))
282 #define PPL_HDR_MAX_ENTRIES \
283 (PPL_HDR_ENTRY_SPACE / sizeof(struct ppl_header_entry))
286 __u8 reserved
[PPL_HDR_RESERVED
];/* reserved space, fill with 0xff */
287 __u32 signature
; /* signature (family number of volume) */
288 __u32 padding
; /* zero pad */
289 __u64 generation
; /* generation number of the header */
290 __u32 entries_count
; /* number of entries in entry array */
291 __u32 checksum
; /* checksum of the header */
292 struct ppl_header_entry entries
[PPL_HDR_MAX_ENTRIES
];
293 } __attribute__ ((__packed__
));