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/* 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_RESERVED_BLOCKS (MD_RESERVED_BYTES / BLOCK_SIZE) #define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS) #define MD_NEW_SIZE_BLOCKS(x) ((x & ~(MD_RESERVED_BLOCKS - 1)) - MD_RESERVED_BLOCKS) #define MD_SB_BYTES 4096 #define MD_SB_WORDS (MD_SB_BYTES / 4) #define MD_SB_BLOCKS (MD_SB_BYTES / BLOCK_SIZE) #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 */ 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 */ __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 12]; /* * 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 */ __u32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */ __u32 major_version; /* 1 */ __u32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */ __u32 pad0; /* always set to 0 when writing */ __u8 set_uuid[16]; /* user-space generated. */ char set_name[32]; /* set and interpreted by user-space */ __u64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/ __u32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */ __u32 layout; /* only for raid5 and raid10 currently */ __u64 size; /* used size of component devices, in 512byte sectors */ __u32 chunksize; /* in 512byte sectors */ __u32 raid_disks; __u32 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. */ __u8 pad1[128-100]; /* set to 0 when written */ /* constant this-device information - 64 bytes */ __u64 data_offset; /* sector start of data, often 0 */ __u64 data_size; /* sectors in this device that can be used for data */ __u64 super_offset; /* sector start of this superblock */ __u64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */ __u32 dev_number; /* permanent identifier of this device - not role in raid */ __u32 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 */ __u64 utime; /* 40 bits second, 24 btes microseconds */ __u64 events; /* incremented when superblock updated */ __u64 resync_offset; /* data before this offset (from data_offset) known to be in sync */ __u32 sb_csum; /* checksum upto devs[max_dev] */ __u32 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. */ __u16 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_ALL 1 #endif