71c0805cb4
As this is used to flag an internal bitmap. Also, introduce symbolic names for feature bits. Signed-off-by: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
247 lines
9 KiB
C
247 lines
9 KiB
C
/*
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md_p.h : physical layout of Linux RAID devices
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Copyright (C) 1996-98 Ingo Molnar, Gadi Oxman
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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You should have received a copy of the GNU General Public License
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(for example /usr/src/linux/COPYING); if not, write to the Free
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Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef _MD_P_H
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#define _MD_P_H
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/*
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* RAID superblock.
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*
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* The RAID superblock maintains some statistics on each RAID configuration.
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* Each real device in the RAID set contains it near the end of the device.
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* Some of the ideas are copied from the ext2fs implementation.
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*
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* We currently use 4096 bytes as follows:
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*
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* word offset function
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*
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* 0 - 31 Constant generic RAID device information.
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* 32 - 63 Generic state information.
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* 64 - 127 Personality specific information.
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* 128 - 511 12 32-words descriptors of the disks in the raid set.
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* 512 - 911 Reserved.
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* 912 - 1023 Disk specific descriptor.
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*/
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/*
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* If x is the real device size in bytes, we return an apparent size of:
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*
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* y = (x & ~(MD_RESERVED_BYTES - 1)) - MD_RESERVED_BYTES
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*
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* and place the 4kB superblock at offset y.
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*/
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#define MD_RESERVED_BYTES (64 * 1024)
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#define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512)
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#define MD_RESERVED_BLOCKS (MD_RESERVED_BYTES / BLOCK_SIZE)
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#define MD_NEW_SIZE_SECTORS(x) ((x & ~(MD_RESERVED_SECTORS - 1)) - MD_RESERVED_SECTORS)
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#define MD_NEW_SIZE_BLOCKS(x) ((x & ~(MD_RESERVED_BLOCKS - 1)) - MD_RESERVED_BLOCKS)
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#define MD_SB_BYTES 4096
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#define MD_SB_WORDS (MD_SB_BYTES / 4)
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#define MD_SB_BLOCKS (MD_SB_BYTES / BLOCK_SIZE)
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#define MD_SB_SECTORS (MD_SB_BYTES / 512)
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/*
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* The following are counted in 32-bit words
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*/
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#define MD_SB_GENERIC_OFFSET 0
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#define MD_SB_PERSONALITY_OFFSET 64
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#define MD_SB_DISKS_OFFSET 128
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#define MD_SB_DESCRIPTOR_OFFSET 992
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#define MD_SB_GENERIC_CONSTANT_WORDS 32
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#define MD_SB_GENERIC_STATE_WORDS 32
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#define MD_SB_GENERIC_WORDS (MD_SB_GENERIC_CONSTANT_WORDS + MD_SB_GENERIC_STATE_WORDS)
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#define MD_SB_PERSONALITY_WORDS 64
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#define MD_SB_DESCRIPTOR_WORDS 32
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#define MD_SB_DISKS 27
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#define MD_SB_DISKS_WORDS (MD_SB_DISKS*MD_SB_DESCRIPTOR_WORDS)
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#define MD_SB_RESERVED_WORDS (1024 - MD_SB_GENERIC_WORDS - MD_SB_PERSONALITY_WORDS - MD_SB_DISKS_WORDS - MD_SB_DESCRIPTOR_WORDS)
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#define MD_SB_EQUAL_WORDS (MD_SB_GENERIC_WORDS + MD_SB_PERSONALITY_WORDS + MD_SB_DISKS_WORDS)
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/*
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* Device "operational" state bits
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*/
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#define MD_DISK_FAULTY 0 /* disk is faulty / operational */
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#define MD_DISK_ACTIVE 1 /* disk is running or spare disk */
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#define MD_DISK_SYNC 2 /* disk is in sync with the raid set */
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#define MD_DISK_REMOVED 3 /* disk is in sync with the raid set */
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#define MD_DISK_WRITEMOSTLY 9 /* disk is "write-mostly" is RAID1 config.
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* read requests will only be sent here in
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* dire need
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*/
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typedef struct mdp_device_descriptor_s {
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__u32 number; /* 0 Device number in the entire set */
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__u32 major; /* 1 Device major number */
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__u32 minor; /* 2 Device minor number */
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__u32 raid_disk; /* 3 The role of the device in the raid set */
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__u32 state; /* 4 Operational state */
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__u32 reserved[MD_SB_DESCRIPTOR_WORDS - 5];
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} mdp_disk_t;
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#define MD_SB_MAGIC 0xa92b4efc
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/*
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* Superblock state bits
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*/
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#define MD_SB_CLEAN 0
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#define MD_SB_ERRORS 1
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#define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */
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typedef struct mdp_superblock_s {
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/*
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* Constant generic information
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*/
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__u32 md_magic; /* 0 MD identifier */
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__u32 major_version; /* 1 major version to which the set conforms */
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__u32 minor_version; /* 2 minor version ... */
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__u32 patch_version; /* 3 patchlevel version ... */
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__u32 gvalid_words; /* 4 Number of used words in this section */
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__u32 set_uuid0; /* 5 Raid set identifier */
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__u32 ctime; /* 6 Creation time */
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__u32 level; /* 7 Raid personality */
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__u32 size; /* 8 Apparent size of each individual disk */
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__u32 nr_disks; /* 9 total disks in the raid set */
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__u32 raid_disks; /* 10 disks in a fully functional raid set */
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__u32 md_minor; /* 11 preferred MD minor device number */
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__u32 not_persistent; /* 12 does it have a persistent superblock */
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__u32 set_uuid1; /* 13 Raid set identifier #2 */
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__u32 set_uuid2; /* 14 Raid set identifier #3 */
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__u32 set_uuid3; /* 15 Raid set identifier #4 */
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__u32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16];
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/*
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* Generic state information
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*/
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__u32 utime; /* 0 Superblock update time */
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__u32 state; /* 1 State bits (clean, ...) */
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__u32 active_disks; /* 2 Number of currently active disks */
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__u32 working_disks; /* 3 Number of working disks */
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__u32 failed_disks; /* 4 Number of failed disks */
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__u32 spare_disks; /* 5 Number of spare disks */
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__u32 sb_csum; /* 6 checksum of the whole superblock */
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#ifdef __BIG_ENDIAN
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__u32 events_hi; /* 7 high-order of superblock update count */
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__u32 events_lo; /* 8 low-order of superblock update count */
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__u32 cp_events_hi; /* 9 high-order of checkpoint update count */
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__u32 cp_events_lo; /* 10 low-order of checkpoint update count */
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#else
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__u32 events_lo; /* 7 low-order of superblock update count */
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__u32 events_hi; /* 8 high-order of superblock update count */
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__u32 cp_events_lo; /* 9 low-order of checkpoint update count */
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__u32 cp_events_hi; /* 10 high-order of checkpoint update count */
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#endif
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__u32 recovery_cp; /* 11 recovery checkpoint sector count */
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__u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 12];
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/*
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* Personality information
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*/
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__u32 layout; /* 0 the array's physical layout */
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__u32 chunk_size; /* 1 chunk size in bytes */
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__u32 root_pv; /* 2 LV root PV */
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__u32 root_block; /* 3 LV root block */
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__u32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4];
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/*
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* Disks information
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*/
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mdp_disk_t disks[MD_SB_DISKS];
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/*
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* Reserved
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*/
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__u32 reserved[MD_SB_RESERVED_WORDS];
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/*
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* Active descriptor
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*/
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mdp_disk_t this_disk;
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} mdp_super_t;
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static inline __u64 md_event(mdp_super_t *sb) {
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__u64 ev = sb->events_hi;
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return (ev<<32)| sb->events_lo;
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}
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/*
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* The version-1 superblock :
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* All numeric fields are little-endian.
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*
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* total size: 256 bytes plus 2 per device.
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* 1K allows 384 devices.
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*/
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struct mdp_superblock_1 {
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/* constant array information - 128 bytes */
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__u32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */
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__u32 major_version; /* 1 */
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__u32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */
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__u32 pad0; /* always set to 0 when writing */
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__u8 set_uuid[16]; /* user-space generated. */
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char set_name[32]; /* set and interpreted by user-space */
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__u64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/
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__u32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */
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__u32 layout; /* only for raid5 and raid10 currently */
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__u64 size; /* used size of component devices, in 512byte sectors */
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__u32 chunksize; /* in 512byte sectors */
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__u32 raid_disks;
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__u32 bitmap_offset; /* sectors after start of superblock that bitmap starts
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* NOTE: signed, so bitmap can be before superblock
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* only meaningful of feature_map[0] is set.
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*/
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__u8 pad1[128-100]; /* set to 0 when written */
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/* constant this-device information - 64 bytes */
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__u64 data_offset; /* sector start of data, often 0 */
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__u64 data_size; /* sectors in this device that can be used for data */
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__u64 super_offset; /* sector start of this superblock */
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__u64 recovery_offset;/* sectors before this offset (from data_offset) have been recovered */
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__u32 dev_number; /* permanent identifier of this device - not role in raid */
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__u32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */
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__u8 device_uuid[16]; /* user-space setable, ignored by kernel */
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__u8 devflags; /* per-device flags. Only one defined...*/
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#define WriteMostly1 1 /* mask for writemostly flag in above */
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__u8 pad2[64-57]; /* set to 0 when writing */
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/* array state information - 64 bytes */
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__u64 utime; /* 40 bits second, 24 btes microseconds */
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__u64 events; /* incremented when superblock updated */
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__u64 resync_offset; /* data before this offset (from data_offset) known to be in sync */
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__u32 sb_csum; /* checksum upto devs[max_dev] */
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__u32 max_dev; /* size of devs[] array to consider */
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__u8 pad3[64-32]; /* set to 0 when writing */
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/* device state information. Indexed by dev_number.
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* 2 bytes per device
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* Note there are no per-device state flags. State information is rolled
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* into the 'roles' value. If a device is spare or faulty, then it doesn't
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* have a meaningful role.
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*/
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__u16 dev_roles[0]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */
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};
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/* feature_map bits */
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#define MD_FEATURE_BITMAP_OFFSET 1
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#define MD_FEATURE_ALL 1
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#endif
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