"""
#define MD_RESERVED_BYTES (64 * 1024)
#define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512)
/*
* 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.
*/
#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)
/*
* 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_CLUSTER_ADD 4 /* Initiate a disk add across the cluster
* For clustered enviroments only.
*/
#define MD_DISK_CANDIDATE 5 /* disk is added as spare (local) until confirmed
* For clustered enviroments only.
*/
#define MD_DISK_FAILFAST 10 /* Send REQ_FAILFAST if there are multiple
* devices available - and don't try to
* correct read errors.
*/
#define MD_DISK_WRITEMOSTLY 9 /* disk is "write-mostly" is RAID1 config.
* read requests will only be sent here in
* dire need
*/
#define MD_DISK_JOURNAL 18 /* disk is used as the write journal in RAID-5/6 */
#define MD_DISK_ROLE_SPARE 0xffff
#define MD_DISK_ROLE_FAULTY 0xfffe
#define MD_DISK_ROLE_JOURNAL 0xfffd
#define MD_DISK_ROLE_MAX 0xff00 /* max value of regular disk role */
typedef struct mdp_device_descriptor_s {
uint32 number; /* 0 Device number in the entire set */
uint32 major; /* 1 Device major number */
uint32 minor; /* 2 Device minor number */
uint32 raid_disk; /* 3 The role of the device in the raid set */
uint32 state; /* 4 Operational state */
uint32 reserved[MD_SB_DESCRIPTOR_WORDS - 5];
} mdp_disk_t;
#define MD_SB_MAGIC 0xa92b4efc
typedef struct mdp_superblock_s {
/*
* Constant generic information
*/
uint32 md_magic; /* 0 MD identifier */
uint32 major_version; /* 1 major version to which the set conforms */
uint32 minor_version; /* 2 minor version ... */
uint32 patch_version; /* 3 patchlevel version ... */
uint32 gvalid_words; /* 4 Number of used words in this section */
char set_uuid0[4]; /* 5 Raid set identifier */
uint32 ctime; /* 6 Creation time */
uint32 level; /* 7 Raid personality */
uint32 size; /* 8 Apparent size of each individual disk */
uint32 nr_disks; /* 9 total disks in the raid set */
uint32 raid_disks; /* 10 disks in a fully functional raid set */
uint32 md_minor; /* 11 preferred MD minor device number */
uint32 not_persistent; /* 12 does it have a persistent superblock */
char set_uuid1[4]; /* 13 Raid set identifier #2 */
char set_uuid2[4]; /* 14 Raid set identifier #3 */
char set_uuid3[4]; /* 15 Raid set identifier #4 */
uint32 gstate_creserved[MD_SB_GENERIC_CONSTANT_WORDS - 16];
/*
* Generic state information
*/
uint32 utime; /* 0 Superblock update time */
uint32 state; /* 1 State bits (clean, ...) */
uint32 active_disks; /* 2 Number of currently active disks */
uint32 working_disks; /* 3 Number of working disks */
uint32 failed_disks; /* 4 Number of failed disks */
uint32 spare_disks; /* 5 Number of spare disks */
uint32 sb_csum; /* 6 checksum of the whole superblock */
uint32 events_lo; /* 7 low-order of superblock update count */
uint32 events_hi; /* 8 high-order of superblock update count */
uint32 cp_events_lo; /* 9 low-order of checkpoint update count */
uint32 cp_events_hi; /* 10 high-order of checkpoint update count */
uint32 recovery_cp; /* 11 recovery checkpoint sector count */
/* There are only valid for minor_version > 90 */
uint64 reshape_position; /* 12,13 next address in array-space for reshape */
uint32 new_level; /* 14 new level we are reshaping to */
uint32 delta_disks; /* 15 change in number of raid_disks */
uint32 new_layout; /* 16 new layout */
uint32 new_chunk; /* 17 new chunk size (bytes) */
uint32 gstate_sreserved[MD_SB_GENERIC_STATE_WORDS - 18];
/*
* Personality information
*/
uint32 layout; /* 0 the array's physical layout */
uint32 chunk_size; /* 1 chunk size in bytes */
uint32 root_pv; /* 2 LV root PV */
uint32 root_block; /* 3 LV root block */
uint32 pstate_reserved[MD_SB_PERSONALITY_WORDS - 4];
/*
* Disks information
*/
mdp_disk_t disks[MD_SB_DISKS];
/*
* Reserved
*/
uint32 reserved[MD_SB_RESERVED_WORDS];
/*
* Active descriptor
*/
mdp_disk_t this_disk;
} mdp_super_t;
#define WriteMostly1 1 /* mask for writemostly flag in above */
#define FailFast1 2 /* Should avoid retries and fixups and just fail */
/*
* 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 */
uint32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */
uint32 major_version; /* 1 */
uint32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */
uint32 pad0; /* always set to 0 when writing */
char set_uuid[16]; /* user-space generated. */
char set_name[32]; /* set and interpreted by user-space */
uint64 ctime; /* lo 40 bits are seconds, top 24 are microseconds or 0*/
int32 level; /* -4 (multipath), -1 (linear), 0,1,4,5 */
uint32 layout; /* only for raid5 and raid10 currently */
uint64 size; /* used size of component devices, in 512byte sectors */
uint32 chunksize; /* in 512byte sectors */
uint32 raid_disks;
union {
uint32 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.
*/
/* only meaningful when feature_map[MD_FEATURE_PPL] is set */
struct {
uint16 offset; /* sectors from start of superblock that ppl starts (signed) */
uint16 size; /* ppl size in sectors */
} ppl;
};
/* These are only valid with feature bit '4' */
uint32 new_level; /* new level we are reshaping to */
uint64 reshape_position; /* next address in array-space for reshape */
uint32 delta_disks; /* change in number of raid_disks */
uint32 new_layout; /* new layout */
uint32 new_chunk; /* new chunk size (512byte sectors) */
uint32 new_offset; /* signed number to add to data_offset in new
* layout. 0 == no-change. This can be
* different on each device in the array.
*/
/* constant this-device information - 64 bytes */
uint64 data_offset; /* sector start of data, often 0 */
uint64 data_size; /* sectors in this device that can be used for data */
uint64 super_offset; /* sector start of this superblock */
union {
uint64 recovery_offset; /* sectors before this offset (from data_offset) have been recovered */
uint64 journal_tail; /* journal tail of journal device (from data_offset) */
};
uint32 dev_number; /* permanent identifier of this device - not role in raid */
uint32 cnt_corrected_read; /* number of read errors that were corrected by re-writing */
char device_uuid[16]; /* user-space setable, ignored by kernel */
uint8 devflags; /* per-device flags. Only two defined... */
/* Bad block log. If there are any bad blocks the feature flag is set.
* If offset and size are non-zero, that space is reserved and available
*/
uint8 bblog_shift; /* shift from sectors to block size */
uint16 bblog_size; /* number of sectors reserved for list */
int32 bblog_offset; /* sector offset from superblock to bblog, signed - not unsigned */
/* array state information - 64 bytes */
uint64 utime; /* 40 bits second, 24 bits microseconds */
uint64 events; /* incremented when superblock updated */
uint64 resync_offset; /* data before this offset (from data_offset) known to be in sync */
uint32 sb_csum; /* checksum up to devs[max_dev] */
uint32 max_dev; /* size of devs[] array to consider */
char 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.
*/
uint16 dev_roles[max_dev]; /* role in array, or 0xffff for a spare, or 0xfffe for faulty */
};
/* non-obvious values for 'level' */
#define LEVEL_MULTIPATH (-4)
#define LEVEL_LINEAR (-1)
#define LEVEL_FAULTY (-5)
/*
* Our supported algorithms
*/
#define ALGORITHM_LEFT_ASYMMETRIC 0 /* Rotating Parity N with Data Restart */
#define ALGORITHM_RIGHT_ASYMMETRIC 1 /* Rotating Parity 0 with Data Restart */
#define ALGORITHM_LEFT_SYMMETRIC 2 /* Rotating Parity N with Data Continuation */
#define ALGORITHM_RIGHT_SYMMETRIC 3 /* Rotating Parity 0 with Data Continuation */
/* Define non-rotating (raid4) algorithms. These allow
* conversion of raid4 to raid5.
*/
#define ALGORITHM_PARITY_0 4 /* P or P,Q are initial devices */
#define ALGORITHM_PARITY_N 5 /* P or P,Q are final devices. */
/* DDF RAID6 layouts differ from md/raid6 layouts in two ways.
* Firstly, the exact positioning of the parity block is slightly
* different between the 'LEFT_*' modes of md and the "_N_*" modes
* of DDF.
* Secondly, or order of datablocks over which the Q syndrome is computed
* is different.
* Consequently we have different layouts for DDF/raid6 than md/raid6.
* These layouts are from the DDFv1.2 spec.
* Interestingly DDFv1.2-Errata-A does not specify N_CONTINUE but
* leaves RLQ=3 as 'Vendor Specific'
*/
#define ALGORITHM_ROTATING_ZERO_RESTART 8 /* DDF PRL=6 RLQ=1 */
#define ALGORITHM_ROTATING_N_RESTART 9 /* DDF PRL=6 RLQ=2 */
#define ALGORITHM_ROTATING_N_CONTINUE 10 /* DDF PRL=6 RLQ=3 */
/* For every RAID5 algorithm we define a RAID6 algorithm
* with exactly the same layout for data and parity, and
* with the Q block always on the last device (N-1).
* This allows trivial conversion from RAID5 to RAID6
*/
#define ALGORITHM_LEFT_ASYMMETRIC_6 16
#define ALGORITHM_RIGHT_ASYMMETRIC_6 17
#define ALGORITHM_LEFT_SYMMETRIC_6 18
#define ALGORITHM_RIGHT_SYMMETRIC_6 19
#define ALGORITHM_PARITY_0_6 20
#define ALGORITHM_PARITY_N_6 ALGORITHM_PARITY_N
"""