| /* | |
| md_p.h : physical layout of Linux RAID devices | |
| Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman | |
| This program is free software; you can redistribute it and/or modify | |
| it under the terms of the GNU General Public License as published by | |
| the Free Software Foundation; either version 2, or (at your option) | |
| any later version. | |
| You should have received a copy of the GNU General Public License | |
| (for example /usr/src/linux/COPYING); if not, write to the Free | |
| Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
| */ | |
| #ifndef _MD_P_H | |
| #define _MD_P_H | |
| /* | |
| * RAID superblock. | |
| * | |
| * The RAID superblock maintains some statistics on each RAID configuration. | |
| * Each real device in the RAID set contains it near the end of the device. | |
| * Some of the ideas are copied from the ext2fs implementation. | |
| * | |
| * We currently use 4096 bytes as follows: | |
| * | |
| * word offset function | |
| * | |
| * 0 - 31 Constant generic RAID device information. | |
| * 32 - 63 Generic state information. | |
| * 64 - 127 Personality specific information. | |
| * 128 - 511 12 32-words descriptors of the disks in the raid set. | |
| * 512 - 911 Reserved. | |
| * 912 - 1023 Disk specific descriptor. | |
| */ | |
| /* | |
| * If x is the real device size in bytes, we return an apparent size of: | |
| * | |
| * y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES | |
| * | |
| * and place the 4kB superblock at offset y. | |
| */ | |
| #define MD_RESERVED_BYTES (64 * 1024) | |
| #define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512) | |
| #define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS) | |
| #define MD_SB_BYTES 4096 | |
| #define MD_SB_WORDS (MD_SB_BYTES / 4) | |
| #define MD_SB_SECTORS (MD_SB_BYTES / 512) | |
| /* | |
| * The following are counted in 32-bit words | |
| */ | |
| #define MD_SB_GENERIC_OFFSET 0 | |
| #define MD_SB_PERSONALITY_OFFSET 64 | |
| #define MD_SB_DISKS_OFFSET 128 | |
| #define MD_SB_DESCRIPTOR_OFFSET 992 | |
| #define MD_SB_GENERIC_CONSTANT_WORDS 32 | |
| #define MD_SB_GENERIC_STATE_WORDS 32 | |
| #define MD_SB_GENERIC_WORDS (MD_SB_GENERIC_CONSTANT_WORDS + MD_SB_GENERIC_STATE_WORDS) | |
| #define MD_SB_PERSONALITY_WORDS 64 | |
| #define MD_SB_DESCRIPTOR_WORDS 32 | |
| #define MD_SB_DISKS 27 | |
| #define MD_SB_DISKS_WORDS (MD_SB_DISKS*MD_SB_DESCRIPTOR_WORDS) | |
| #define MD_SB_RESERVED_WORDS (1024 - MD_SB_GENERIC_WORDS - MD_SB_PERSONALITY_WORDS - MD_SB_DISKS_WORDS - MD_SB_DESCRIPTOR_WORDS) | |
| #define MD_SB_EQUAL_WORDS (MD_SB_GENERIC_WORDS + MD_SB_PERSONALITY_WORDS + MD_SB_DISKS_WORDS) | |
| /* | |
| * Device "operational" state bits | |
| */ | |
| #define MD_DISK_FAULTY 0 /* disk is faulty / operational */ | |
| #define MD_DISK_ACTIVE 1 /* disk is running or spare disk */ | |
| #define MD_DISK_SYNC 2 /* disk is in sync with the raid set */ | |
| #define MD_DISK_REMOVED 3 /* disk is in sync with the raid set */ | |
| #define MD_DISK_WRITEMOSTLY 9 /* disk is "write-mostly" is RAID1 config. | |
| * read requests will only be sent here in | |
| * dire need | |
| */ | |
| typedef struct mdp_device_descriptor_s { | |
| __u32 number; /* 0 Device number in the entire set */ | |
| __u32 major; /* 1 Device major number */ | |
| __u32 minor; /* 2 Device minor number */ | |
| __u32 raid_disk; /* 3 The role of the device in the raid set */ | |
| __u32 state; /* 4 Operational state */ | |
| __u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5]; | |
| } mdp_disk_t; | |
| #define MD_SB_MAGIC 0xa92b4efc | |
| /* | |
| * Superblock state bits | |
| */ | |
| #define MD_SB_CLEAN 0 | |
| #define MD_SB_ERRORS 1 | |
| #define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */ | |
| /* | |
| * Notes: | |
| * - if an array is being reshaped (restriped) in order to change the | |
| * the number of active devices in the array, 'raid_disks' will be | |
| * the larger of the old and new numbers. 'delta_disks' will | |
| * be the "new - old". So if +ve, raid_disks is the new value, and | |
| * "raid_disks-delta_disks" is the old. If -ve, raid_disks is the | |
| * old value and "raid_disks+delta_disks" is the new (smaller) value. | |
| */ | |
| typedef struct mdp_superblock_s { | |
| /* | |
| * Constant generic information | |
| */ | |
| __u32 md_magic; /* 0 MD identifier */ | |
| __u32 major_version; /* 1 major version to which the set conforms */ | |
| __u32 minor_version; /* 2 minor version ... */ | |
| __u32 patch_version; /* 3 patchlevel version ... */ | |
| __u32 gvalid_words; /* 4 Number of used words in this section */ | |
| __u32 set_uuid0; /* 5 Raid set identifier */ | |
| __u32 ctime; /* 6 Creation time */ | |
| __u32 level; /* 7 Raid personality */ | |
| __u32 size; /* 8 Apparent size of each individual disk */ | |
| __u32 nr_disks; /* 9 total disks in the raid set */ | |
| __u32 raid_disks; /* 10 disks in a fully functional raid set */ | |
| __u32 md_minor; /* 11 preferred MD minor device number */ | |
| __u32 not_persistent; /* 12 does it have a persistent superblock */ | |
| __u32 set_uuid1; /* 13 Raid set identifier #2 */ | |
| __u32 set_uuid2; /* 14 Raid set identifier #3 */ | |
| __u32 set_uuid3; /* 15 Raid set identifier #4 */ | |
| __u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16]; | |
| /* | |
| * Generic state information | |
| */ | |
| __u32 utime; /* 0 Superblock update time */ | |
| __u32 state; /* 1 State bits (clean, ...) */ | |
| __u32 active_disks; /* 2 Number of currently active disks */ | |
| __u32 working_disks; /* 3 Number of working disks */ | |
| __u32 failed_disks; /* 4 Number of failed disks */ | |
| __u32 spare_disks; /* 5 Number of spare disks */ | |
| __u32 sb_csum; /* 6 checksum of the whole superblock */ | |
| #ifdef __BIG_ENDIAN | |
| __u32 events_hi; /* 7 high-order of superblock update count */ | |
| __u32 events_lo; /* 8 low-order of superblock update count */ | |
| __u32 cp_events_hi; /* 9 high-order of checkpoint update count */ | |
| __u32 cp_events_lo; /* 10 low-order of checkpoint update count */ | |
| #else | |
| __u32 events_lo; /* 7 low-order of superblock update count */ | |
| __u32 events_hi; /* 8 high-order of superblock update count */ | |
| __u32 cp_events_lo; /* 9 low-order of checkpoint update count */ | |
| __u32 cp_events_hi; /* 10 high-order of checkpoint update count */ | |
| #endif | |
| __u32 recovery_cp; /* 11 recovery checkpoint sector count */ | |
| /* There are only valid for minor_version > 90 */ | |
| __u64 reshape_position; /* 12,13 next address in array-space for reshape */ | |
| __u32 new_level; /* 14 new level we are reshaping to */ | |
| __u32 delta_disks; /* 15 change in number of raid_disks */ | |
| __u32 new_layout; /* 16 new layout */ | |
| __u32 new_chunk; /* 17 new chunk size (bytes) */ | |
| __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 18]; | |
| /* | |
| * Personality information | |
| */ | |
| __u32 layout; /* 0 the array's physical layout */ | |
| __u32 chunk_size; /* 1 chunk size in bytes */ | |
| __u32 root_pv; /* 2 LV root PV */ | |
| __u32 root_block; /* 3 LV root block */ | |
| __u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4]; | |
| /* | |
| * Disks information | |
| */ | |
| mdp_disk_t disks[MD_SB_DISKS]; | |
| /* | |
| * Reserved | |
| */ | |
| __u32 reserved[MD_SB_RESERVED_WORDS]; | |
| /* | |
| * Active descriptor | |
| */ | |
| mdp_disk_t this_disk; | |
| } mdp_super_t; | |
| static inline __u64 md_event(mdp_super_t *sb) { | |
| __u64 ev = sb->events_hi; | |
| return (ev<<32)| sb->events_lo; | |
| } | |
| /* | |
| * The version-1 superblock : | |
| * All numeric fields are little-endian. | |
| * | |
| * total size: 256 bytes plus 2 per device. | |
| * 1K allows 384 devices. | |
| */ | |
| struct mdp_superblock_1 { | |
| /* constant array information - 128 bytes */ | |
| __le32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */ | |
| __le32 major_version; /* 1 */ | |
| __le32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */ | |
| __le32 pad0; /* always set to 0 when writing */ | |
| __u8 set_uuid[16]; /* user-space generated. */ | |
| char set_name[32]; /* set and interpreted by user-space */ | |
| __le64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/ | |
| __le32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */ | |
| __le32 layout; /* only for raid5 and raid10 currently */ | |
| __le64 size; /* used size of component devices, in 512byte sectors */ | |
| __le32 chunksize; /* in 512byte sectors */ | |
| __le32 raid_disks; | |
| __le32 bitmap_offset; /* sectors after start of superblock that bitmap starts | |
| * NOTE: signed, so bitmap can be before superblock | |
| * only meaningful of feature_map[0] is set. | |
| */ | |
| /* These are only valid with feature bit '4' */ | |
| __le32 new_level; /* new level we are reshaping to */ | |
| __le64 reshape_position; /* next address in array-space for reshape */ | |
| __le32 delta_disks; /* change in number of raid_disks */ | |
| __le32 new_layout; /* new layout */ | |
| __le32 new_chunk; /* new chunk size (bytes) */ | |
| __u8 pad1[128-124]; /* set to 0 when written */ | |
| /* constant this-device information - 64 bytes */ | |
| __le64 data_offset; /* sector start of data, often 0 */ | |
| __le64 data_size; /* sectors in this device that can be used for data */ | |
| __le64 super_offset; /* sector start of this superblock */ | |
| __le64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */ | |
| __le32 dev_number; /* permanent identifier of this device - not role in raid */ | |
| __le32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */ | |
| __u8 device_uuid[16]; /* user-space setable, ignored by kernel */ | |
| __u8 devflags; /* per-device flags. Only one defined...*/ | |
| #define WriteMostly1 1 /* mask for writemostly flag in above */ | |
| __u8 pad2[64-57]; /* set to 0 when writing */ | |
| /* array state information - 64 bytes */ | |
| __le64 utime; /* 40 bits second, 24 btes microseconds */ | |
| __le64 events; /* incremented when superblock updated */ | |
| __le64 resync_offset; /* data before this offset (from data_offset) known to be in sync */ | |
| __le32 sb_csum; /* checksum upto devs[max_dev] */ | |
| __le32 max_dev; /* size of devs[] array to consider */ | |
| __u8 pad3[64-32]; /* set to 0 when writing */ | |
| /* device state information. Indexed by dev_number. | |
| * 2 bytes per device | |
| * Note there are no per-device state flags. State information is rolled | |
| * into the 'roles' value. If a device is spare or faulty, then it doesn't | |
| * have a meaningful role. | |
| */ | |
| __le16 dev_roles[0]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */ | |
| }; | |
| /* feature_map bits */ | |
| #define MD_FEATURE_BITMAP_OFFSET 1 | |
| #define MD_FEATURE_RECOVERY_OFFSET 2 /* recovery_offset is present and | |
| * must be honoured | |
| */ | |
| #define MD_FEATURE_RESHAPE_ACTIVE 4 | |
| #define MD_FEATURE_ALL (1|2|4) | |
| #endif | |