xfs_check, xfs_check64 - check XFS filesystem consistency
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xfs_check [ -i ino ] ... [ -b bno ] ... [ -s ] [ -v ] xfs_special xfs_check -f [ -i ino ] ... [ -b bno ] ... [ -s ] [ -v ] file xfs_check64 [ -i ino ] ... [ -b bno ] ... [ -s ] [ -v ] xfs_special xfs_check64 -f [ -i ino ] ... [ -b bno ] ... [ -s ] [ -v ] file |
xfs_check checks whether an XFS filesystem is consistent. It is normally run only when there is reason to believe that the filesystem has a consistency problem. The filesystem to be checked is specified by the xfs_special argu- ment, which should be the disk or volume device for the filesystem. Filesystems stored in files can also be checked, using the -f flag. The filesystem should normally be unmounted or read-only during the execution of xfs_check. Otherwise, spurious problems are reported.
xfs_check64 is a 64-bit version of xfs_check which is not as susceptible to running out of memory. It is available only on 64-bit capable systems.
The options to xfs_check are:
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-f |
Specifies that the special device is actually a file (see the mkfs_xfs -d file option). This might happen if an image copy of a filesystem has been made into an ordinary file. |
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-s |
Specifies that only serious errors should be reported. Serious errors are those that make it impossible to find major data structures in the filesystem. This option can be used to cut down the amount of output when there is a serious problem, when the output might make it difficult to see what the real problem is. |
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-v |
Specifies verbose output; it is impossibly long for a reasonably-sized filesystem. This option is intended for internal use only. |
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-i ino |
Specifies verbose behavior for a specific inode. For instance, it can be used to locate all the blocks asso- ciated with a given inode. |
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-b bno |
Specifies verbose behavior for a specific filesystem block. For instance, it can be used to determine what a specific block is used for. The block number is a "file system block number". Conversion between disk addresses (i.e. addresses reported by xfs_bmap) and file system blocks may be accom- plished using xfs_db's convert command. |
Any non-verbose output from xfs_check means that the filesystem has an inconsistency. The filesystem can be repaired using either xfs_repair(1M) to fix the filesystem in place, or by using xfsdump(1M) and mkfs_xfs(1M) to dump the filesystem, make a new filesystem, then use xfsrestore(1M) to restore the data onto the new filesystem. Note that xfsdump may fail on a corrupt filesystem. However, if the filesystem is mountable, xfsdump can be used to try and save important data before repairing the filesystem with xfs_repair. If the filesystem is not mountable though, xfs_repair is the only viable option.
Under one circumstance, xfs_check unfortunately might dump core rather than produce useful output. If the filesystem is completely corrupt, a core dump might be produced instead of the message xxx is not a valid filesys- tem
If the filesystem is very large (has many files) then xfs_check might run out of memory. In this case the message out of memory is printed, and if the system running xfs_check supports execution of 64-bit binaries, then a sugges- tion to run xfs_check64 is printed as well.
The following is a description of the most likely problems and the associated messages. Most of the diagnostics produced are only meaningful with an understanding of the structure of the filesystem.
agf_freeblks n, counted m in ag a
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The freeblocks count in the allocation group header for allocation group a doesn't match the |
agf_longest n, counted m in ag a
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The longest free extent in the allocation group header for allocation group a doesn't match |
agi_count n, counted m in ag a
The allocated inode count in the allocation group header for allocation group a doesn't
match the number of inodes counted in the allocation group.
agi_freecount n, counted m in ag a
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The free inode count in the allocation group header for allocation group a doesn't match the |
block a/b expected inum 0 got i
The block number is specified as a pair (allocation group number, block in the allocation
group). The block is used multiple times (shared), between multiple inodes. This message
usually follows a message of the next type.
block a/b expected type unknown got y
The block is used multiple times (shared).
block a/b type unknown not expected
The block is unaccounted for (not in the freelist and not in use).
link count mismatch for inode nnn (name xxx), nlink m, counted n
The inode has a bad link count (number of references in directories).
rtblock b expected inum 0 got i
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The block is used multiple times (shared), between multiple inodes. This message usually |
rtblock b expected type unknown got y
The real-time block is used multiple times (shared).
rtblock b type unknown not expected
The real-time block is unaccounted for (not in the freelist and not in use).
sb_fdblocks n, counted m
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The number of free data blocks recorded in the superblock doesn't match the number |
sb_frextents n, counted m
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The number of free real-time extents recorded in the superblock doesn't match the number |
sb_icount n, counted m
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The number of allocated inodes recorded in the superblock doesn't match the number allo- |
sb_ifree n, counted m The number of free inodes recorded in the superblock doesn't match the number free in the
filesystem.
mkfs_xfs(1M), xfsdump(1M), xfsrestore(1M), xfs_ncheck(1M), xfs_repair(1M), xfs(4).