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Diffstat (limited to 'md_p.h')
| -rw-r--r-- | md_p.h | 172 |
1 files changed, 172 insertions, 0 deletions
@@ -0,0 +1,172 @@ +/* + 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 */ + +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 + +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 */ +#else + __u32 events_lo; /* 7 low-order of superblock update count */ + __u32 events_hi; /* 8 high-order of superblock update count */ +#endif + __u32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 9]; + + /* + * 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; +} + +#endif + |