xfs_repair - repair an XFS filesystem
] [ -m maxmem
] [ -c
] [ -o
] ] [ -t interval
] [ -r rtdev
repairs corrupt or damaged XFS filesystems (see
(5)). The filesystem is specified using the device
which should be the device name of the disk partition or volume containing the
filesystem. If given the name of a block device, xfs_repair
attempt to find the raw device associated with the specified block device and
will use the raw device instead.
Regardless, the filesystem to be repaired must be unmounted, otherwise, the
resulting filesystem may be inconsistent or corrupt.
- Specifies that the filesystem image to be processed is stored in a regular
file at device (see the mkfs.xfs -d file option).
This might happen if an image copy of a filesystem has been copied or
written into an ordinary file. This option implies that any external log
or realtime section is also in an ordinary file.
- Force Log Zeroing. Forces xfs_repair to zero the log even if it is
dirty (contains metadata changes). When using this option the filesystem
will likely appear to be corrupt, and can cause the loss of user files
- -l logdev
- Specifies the device special file where the filesystem's external log
resides. Only for those filesystems which use an external log. See the
mkfs.xfs -l option, and refer to xfs(5) for a detailed
description of the XFS log.
- -r rtdev
- Specifies the device special file where the filesystem's realtime section
resides. Only for those filesystems which use a realtime section. See the
mkfs.xfs -r option, and refer to xfs(5) for a detailed
description of the XFS realtime section.
- No modify mode. Specifies that xfs_repair should not modify the
filesystem but should only scan the filesystem and indicate what repairs
would have been made.
- Disable prefetching of inode and directory blocks. Use this option if you
find xfs_repair gets stuck and stops proceeding. Interrupting a
stuck xfs_repair is safe.
- -m maxmem
- Specifies the approximate maximum amount of memory, in megabytes, to use
for xfs_repair. xfs_repair has its own internal block cache
which will scale out up to the lesser of the process's virtual address
limit or about 75% of the system's physical RAM. This option overrides
- NOTE: These memory limits are only approximate and may use more
than the specified limit.
- -c subopt=value
- Change filesystem parameters. Refer to xfs_admin(8) for information
on changing filesystem parameters.
Override what the program might conclude about the filesystem if left to its own
- The suboptions supported are:
- overrides the default buffer cache hash size. The total number of buffer
cache entries are limited to 8 times this amount. The default size is set
to use up the remainder of 75% of the system's physical RAM size.
- This creates additional processing threads to parallel process AGs that
span multiple concat units. This can significantly reduce repair times on
concat based filesystems.
- Check the filesystem even if geometry information could not be validated.
Geometry information can not be validated if only a single allocation
group exists and thus we do not have a backup superblock available, or if
there are two allocation groups and the two superblocks do not agree on
the filesystem geometry. Only use this option if you validated the
geometry yourself and know what you are doing. If In doubt run in no
modify mode first.
- -t interval
- Modify reporting interval, specified in seconds. During long runs
xfs_repair outputs its progress every 15 minutes. Reporting is only
activated when ag_stride is enabled.
- Verbose output.
- Repair dangerously. Allow xfs_repair to repair an XFS filesystem
mounted read only. This is typically done on a root filesystem from single
user mode, immediately followed by a reboot.
- Prints the version number and exits.
Inconsistencies corrected include the following:
- Inode and inode blockmap (addressing) checks: bad magic number in inode,
bad magic numbers in inode blockmap blocks, extents out of order,
incorrect number of records in inode blockmap blocks, blocks claimed that
are not in a legal data area of the filesystem, blocks that are claimed by
more than one inode.
- Inode allocation map checks: bad magic number in inode map blocks, inode
state as indicated by map (free or in-use) inconsistent with state
indicated by the inode, inodes referenced by the filesystem that do not
appear in the inode allocation map, inode allocation map referencing
blocks that do not appear to contain inodes.
- Size checks: number of blocks claimed by inode inconsistent with inode
size, directory size not block aligned, inode size not consistent with
- Directory checks: bad magic numbers in directory blocks, incorrect number
of entries in a directory block, bad freespace information in a directory
leaf block, entry pointing to an unallocated (free) or out of range inode,
overlapping entries, missing or incorrect dot and dotdot entries, entries
out of hashvalue order, incorrect internal directory pointers, directory
type not consistent with inode format and size.
- Pathname checks: files or directories not referenced by a pathname
starting from the filesystem root, illegal pathname components.
- Link count checks: link counts that do not agree with the number of
directory references to the inode.
- Freemap checks: blocks claimed free by the freemap but also claimed by an
inode, blocks unclaimed by any inode but not appearing in the
- Super Block checks: total free block and/or free i-node count incorrect,
filesystem geometry inconsistent, secondary and primary superblocks
Orphaned files and directories (allocated, in-use but unreferenced) are
reconnected by placing them in the lost+found
directory. The name
assigned is the inode number.
aborts on most disk I/O errors. Therefore, if you are trying
to repair a filesystem that was damaged due to a disk drive failure, steps
should be taken to ensure that all blocks in the filesystem are readable and
writable before attempting to use xfs_repair
to repair the filesystem.
A possible method is using dd
(8) to copy the data onto a good disk.
The directory lost+found
does not have to already exist in the filesystem
being repaired. If the directory does not exist, it is automatically created
if required. If it already exists, it will be checked for consistency and if
valid will be used for additional orphaned files. Invalid lost+found
directories are removed and recreated. Existing files in a valid
are not removed or renamed.
XFS has both primary and secondary superblocks. xfs_repair
information in the primary superblock to automatically find and validate the
primary superblock against the secondary superblocks before proceeding. Should
the primary be too corrupted to be useful in locating the secondary
superblocks, the program scans the filesystem until it finds and validates
some secondary superblocks. At that point, it generates a primary superblock.
If quotas are in use, it is possible that xfs_repair
will clear some or
all of the filesystem quota information. If so, the program issues a warning
just before it terminates. If all quota information is lost, quotas are
disabled and the program issues a warning to that effect.
Note that xfs_repair
does not check the validity of quota limits. It is
recommended that you check the quota limit information manually after
. Also, space usage information is automatically regenerated
the next time the filesystem is mounted with quotas turned on, so the next
quota mount of the filesystem may take some time.
issues informative messages as it proceeds indicating what it
has found that is abnormal or any corrective action that it has taken. Most of
the messages are completely understandable only to those who are knowledgeable
about the structure of the filesystem. Some of the more common messages are
explained here. Note that the language of the messages is slightly different
is run in no-modify mode because the program is not
changing anything on disk. No-modify mode indicates what it would do to repair
the filesystem if run without the no-modify flag.
disconnected inode ino, moving to lost+found
disconnected dir inode ino, moving to lost+found
- An inode numbered ino was not connected to the filesystem directory
tree and was reconnected to the lost+found directory. The inode is
assigned the name of its inode number (ino). If a lost+found
directory does not exist, it is automatically created.
imap claims in-use inode ino is free, correcting imap
- As above only the inode is a directory inode. If a directory inode is
attached to lost+found, all of its children (if any) stay attached
to the directory and therefore get automatically reconnected when the
directory is reconnected.
imap claims free inode ino is in use, correcting imap
- The inode allocation map thinks that inode ino is free whereas
examination of the inode indicates that the inode may be in use (although
it may be disconnected). The program updates the inode allocation
resetting inode ino nlinks from x to y
- The inode allocation map thinks that inode ino is in use whereas
examination of the inode indicates that the inode is not in use and
therefore is free. The program updates the inode allocation map.
fork-type fork in ino ino claims used block
- The program detected a mismatch between the number of valid directory
entries referencing inode ino and the number of references recorded
in the inode and corrected the the number in the inode.
fork-type fork in ino ino claims dup extent ...
- Inode ino claims a block bno that is used (claimed) by
either another inode or the filesystem itself for metadata storage. The
fork-type is either data or attr indicating whether
the problem lies in the portion of the inode that tracks regular data or
the portion of the inode that stores XFS attributes. If the inode is a
real-time (rt) inode, the message says so. Any inode that claims blocks
used by the filesystem is deleted. If two or more inodes claim the same
block, they are both deleted.
inode ino - bad extent ...
- Inode ino claims a block in an extent known to be claimed more than
once. The offset in the inode, start and length of the extent is given.
The message is slightly different if the inode is a real-time (rt) inode
and the extent is therefore a real-time (rt) extent.
bad fork-type fork in inode ino
- An extent record in the blockmap of inode ino claims blocks that
are out of the legal range of the filesystem. The message supplies the
start, end, and file offset of the extent. The message is slightly
different if the extent is a real-time (rt) extent.
cleared inode ino
- There was something structurally wrong or inconsistent with the data
structures that map offsets to filesystem blocks.
bad attribute fork in inode ino
- There was something wrong with the inode that was uncorrectable so the
program freed the inode. This usually happens because the inode claims
blocks that are used by something else or the inode itself is badly
corrupted. Typically, this message is preceded by one or more messages
indicating why the inode needed to be cleared.
, clearing attr fork
correcting nextents for inode ino
- There was something wrong with the portion of the inode that stores XFS
attributes (the attribute fork) so the program reset the attribute fork.
As a result of this, all attributes on that inode are lost.
, was x -
entry name in dir dir_ino not consistent with ..
value (xxxx) in dir ino ino,
junking entry name in directory inode dir_ino
- The program found that the number of extents used to store the data in the
inode is wrong and corrected the number. The message refers to nextents if
the count is wrong on the number of extents used to store attribute
entry name in dir dir_ino references already
connected dir ino ino, junking entry name
in directory inode dir_ino
- The entry name in directory inode dir_ino references a
directory inode ino. However, the .. entry in directory ino
does not point back to directory dir_ino, so the program deletes
the entry name in directory inode dir_ino. If the directory
inode ino winds up becoming a disconnected inode as a result of
this, it is moved to lost+found later.
entry references free inode ino in directory
dir_ino, will clear entry
- The entry name in directory inode dir_ino points to a
directory inode ino that is known to be a child of another
directory. Therefore, the entry is invalid and is deleted. This message
refers to an entry in a small directory. If this were a large directory,
the last phrase would read "will clear entry".
- An entry in directory inode dir_ino references an inode ino
that is known to be free. The entry is therefore invalid and is deleted.
This message refers to a large directory. If the directory were small, the
message would read "junking entry ...".
(no modify node) will return a status of 1 if filesystem
corruption was detected and 0 if no filesystem corruption was detected.
run without the -n option will always return a status code
The filesystem to be checked and repaired must have been unmounted cleanly using
normal system administration procedures (the umount
(8) command or
system shutdown), not as a result of a crash or system reset. If the
filesystem has not been unmounted cleanly, mount it and unmount it cleanly
before running xfs_repair
does not do a thorough job on XFS extended attributes. The
structure of the attribute fork will be consistent, but only the contents of
attribute forks that will fit into an inode are checked. This limitation will
be fixed in the future.
The no-modify mode (-n
option) is not completely accurate. It does not
catch inconsistencies in the freespace and inode maps, particularly lost
blocks or subtly corrupted maps (trees).
The no-modify mode can generate repeated warnings about the same problems
because it cannot fix the problems as they are encountered.
If a filesystem fails to be repaired, a metadump image can be generated with
(8) and be sent to an XFS maintainer to be analysed and
fixed and/or improved.