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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | DIAGNOSTICS | EXIT STATUS | DIRTY LOGS | BUGS | SEE ALSO | COLOPHON |
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xfs_repair(8) System Manager's Manual xfs_repair(8)
xfs_repair - repair an XFS filesystem
xfs_repair [ -dfLPv ] [ -n | -e ] [ -m maxmem ] [ -c subopt=value
] [ -o subopt[=value] ] [ -t interval ] [ -l logdev ] [ -r rtdev
] device
xfs_repair -V
xfs_repair repairs corrupt or damaged XFS filesystems (see
xfs(5)). The filesystem is specified using the device argument
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 will 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.
-f 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.
-L 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 and/or data.
See the DIRTY LOGS section for more information.
-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.
-n 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. This
option cannot be used together with -e.
-P 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 these
limits.
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.
-o subopt[=value]
Override what the program might conclude about the
filesystem if left to its own devices.
The suboptions supported are:
bhash=bhashsize
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.
ag_stride=ags_per_concat_unit
This creates additional processing threads to
parallel process AGs that span multiple concat
units. This can significantly reduce repair
times on concat based filesystems.
force_geometry
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.
noquota
Don't validate quota counters at all.
Quotacheck will be run during the next mount to
recalculate all values.
-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.
-v Verbose output. May be specified multiple times to
increase verbosity.
-d 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.
-e If any metadata corruption was repaired, the status
returned is 4 instead of the usual 0. This option cannot
be used together with -n.
-V Prints the version number and exits.
Checks Performed
The correctness of the crc32c checksum implementation will be
tested before examining the filesystem. If the test fails, the
program will abort.
Inconsistencies corrected include the following:
1. 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.
2. 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.
3. Size checks: number of blocks claimed by inode
inconsistent with inode size, directory size not block
aligned, inode size not consistent with inode format.
4. 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.
5. Pathname checks: files or directories not referenced by a
pathname starting from the filesystem root, illegal
pathname components.
6. Link count checks: link counts that do not agree with the
number of directory references to the inode.
7. Freemap checks: blocks claimed free by the freemap but
also claimed by an inode, blocks unclaimed by any inode
but not appearing in the freemap.
8. Super Block checks: total free block and/or free i-node
count incorrect, filesystem geometry inconsistent,
secondary and primary superblocks contradictory.
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.
Disk Errors
xfs_repair 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.
lost+found
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 lost+found are
not removed or renamed.
Corrupted Superblocks
XFS has both primary and secondary superblocks. xfs_repair uses
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.
Quotas
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 xfs_repair. 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.
xfs_repair 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 if
xfs_repair 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
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.
disconnected dir inode ino, moving to lost+found
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 in-use inode ino is free, 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 map.
imap claims free inode ino is in use, correcting imap
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.
resetting inode ino nlinks from x to y
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 used block bno
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.
fork-type fork in ino ino claims dup 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.
inode ino - bad extent ...
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.
bad fork-type fork in inode ino
There was something structurally wrong or inconsistent
with the data structures that map offsets to filesystem
blocks.
cleared 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.
bad attribute fork in inode ino, clearing attr fork
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.
correcting nextents for inode ino, was x - counted y
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 information.
entry name in dir dir_ino not consistent with .. value (xxxx) in
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 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 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".
entry references free inode ino in directory dir_ino, 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 ...".
xfs_repair -n (no modify mode) will return a status of 1 if
filesystem corruption was detected and 0 if no filesystem
corruption was detected. xfs_repair run without the -n option
will always return a status code of 0 if it completes without
problems, unless the flag -e is used. If it is used, then status
4 is reported when any issue with the filesystem was found, but
could be fixed. If a runtime error is encountered during
operation, it will return a status of 1. In this case, xfs_repair
should be restarted. If xfs_repair is unable to proceed due to a
dirty log, it will return a status of 2. See below.
Due to the design of the XFS log, a dirty log can only be
replayed by the kernel, on a machine having the same CPU
architecture as the machine which was writing to the log.
xfs_repair cannot replay a dirty log and will exit with a status
code of 2 when it detects a dirty log.
In this situation, the log can be replayed by mounting and
immediately unmounting the filesystem on the same class of
machine that crashed. Please make sure that the machine's
hardware is reliable before replaying to avoid compounding the
problems.
If mounting fails, the log can be erased by running xfs_repair
with the -L option. All metadata updates in progress at the time
of the crash will be lost, which may cause significant filesystem
damage. This should only be used as a last resort.
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.
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 xfs_metadump(8) and be sent to an XFS maintainer
to be analysed and xfs_repair fixed and/or improved.
dd(1), mkfs.xfs(8), umount(8), xfs_admin(8), xfs_metadump(8),
xfs(5).
This page is part of the xfsprogs (utilities for XFS filesystems)
project. Information about the project can be found at
⟨http://xfs.org/⟩. If you have a bug report for this manual page,
send it to [email protected]. This page was obtained
from the project's upstream Git repository
⟨https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git⟩ on
2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2024-05-17.) If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to [email protected]
xfs_repair(8)
Pages that refer to this page: ioctl_xfs_scrub_metadata(2), fsck.xfs(8), xfs_admin(8), xfs_db(8), xfs_mdrestore(8), xfs_metadump(8), xfs_scrub(8)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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