-l

Specifies the device special file where the filesystem's external log resides. Only for those filesys‐tems which use an external log. See the mkfs.xfs -l option, and refer to xfs(5) for a detaileddescription of the XFS log.

-r

Specifies the device special file where the filesystem's realtime section resides. Only for thosefilesystems which use a realtime section. See the mkfs.xfs -r option, and refer to xfs(5) for adetailed description of the XFS realtime section.

-m

Specifies the approximate maximum amount of memory, in megabytes, to use for xfs_repair. xfs_repairhas its own internal block cache which will scale out up to the lesser of the process's virtual addresslimit 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

Change filesystem parameters. Refer to xfs_admin(8) for information on changing filesystem parameters.

-o

Override what the program might conclude about the filesystem if left to its own devices.The suboptions supported are:bhash=bhashsizeoverrides the default buffer cache hash size. The total number of buffer cache entries arelimited to 8 times this amount. The default size is set to use up the remainder of 75% of thesystem's physical RAM size.ag_stride=ags_per_concat_unitThis creates additional processing threads to parallel process AGs that span multiple concatunits. This can significantly reduce repair times on concat based filesystems.force_geometryCheck the filesystem even if geometry information could not be validated. Geometry informa‐tion can not be validated if only a single allocation group exists and thus we do not have abackup superblock available, or if there are two allocation groups and the two superblocks donot agree on the filesystem geometry. Only use this option if you validated the geometryyourself and know what you are doing. If In doubt run in no modify mode first.

-t

Modify reporting interval, specified in seconds. During long runs xfs_repair outputs its progress every15 minutes. Reporting is only activated when ag_stride is enabled.

-v

Verbose output. May be specified multiple times to increase verbosity.

-V

Checks PerformedInconsistencies corrected include the following:1. Inode and inode blockmap (addressing) checks: bad magic number in inode, bad magic numbers in inodeblockmap blocks, extents out of order, incorrect number of records in inode blockmap blocks, blocksclaimed that are not in a legal data area of the filesystem, blocks that are claimed by more than oneinode.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 filesystemthat do not appear in the inode allocation map, inode allocation map referencing blocks that do notappear to contain inodes.3. Size checks: number of blocks claimed by inode inconsistent with inode size, directory size not blockaligned, inode size not consistent with inode format.4. Directory checks: bad magic numbers in directory blocks, incorrect number of entries in a directoryblock, bad freespace information in a directory leaf block, entry pointing to an unallocated (free) orout of range inode, overlapping entries, missing or incorrect dot and dotdot entries, entries out ofhashvalue order, incorrect internal directory pointers, directory type not consistent with inode formatand 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 byany inode but not appearing in the freemap.8. Super Block checks: total free block and/or free i-node count incorrect, filesystem geometry inconsis‐tent, secondary and primary superblocks contradictory.Orphaned files and directories (allocated, in-use but unreferenced) are reconnected by placing them in thelost+found directory. The name assigned is the inode number.Disk Errorsxfs_repair aborts on most disk I/O errors. Therefore, if you are trying to repair a filesystem that was dam‐aged due to a disk drive failure, steps should be taken to ensure that all blocks in the filesystem are read‐able and writable before attempting to use xfs_repair to repair the filesystem. A possible method is usingdd(8) to copy the data onto a good disk.lost+foundThe directory lost+found does not have to already exist in the filesystem being repaired. If the directorydoes not exist, it is automatically created if required. If it already exists, it will be checked for consis‐tency and if valid will be used for additional orphaned files. Invalid lost+found directories are removed andrecreated. Existing files in a valid lost+found are not removed or renamed.Corrupted SuperblocksXFS has both primary and secondary superblocks. xfs_repair uses information in the primary superblock toautomatically 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 thefilesystem until it finds and validates some secondary superblocks. At that point, it generates a primarysuperblock.QuotasIf quotas are in use, it is possible that xfs_repair will clear some or all of the filesystem quota informa‐tion. If so, the program issues a warning just before it terminates. If all quota information is lost, quo‐tas 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 quotalimit information manually after xfs_repair. Also, space usage information is automatically regenerated thenext time the filesystem is mounted with quotas turned on, so the next quota mount of the filesystem may takesome time.DIAGNOSTICSxfs_repair issues informative messages as it proceeds indicating what it has found that is abnormal or anycorrective action that it has taken. Most of the messages are completely understandable only to those who areknowledgeable 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 becausethe program is not changing anything on disk. No-modify mode indicates what it would do to repair thefilesystem if run without the no-modify flag.disconnected inode ino, moving to lost+foundAn inode numbered ino was not connected to the filesystem directory tree and was reconnected to thelost+found directory. The inode is assigned the name of its inode number (ino). If a lost+found direc‐tory does not exist, it is automatically created.disconnected dir inode ino, moving to lost+foundAs above only the inode is a directory inode. If a directory inode is attached to lost+found, all ofits children (if any) stay attached to the directory and therefore get automatically reconnected whenthe directory is reconnected.imap claims in-use inode ino is free, correcting imapThe inode allocation map thinks that inode ino is free whereas examination of the inode indicates thatthe inode may be in use (although it may be disconnected). The program updates the inode allocationmap.imap claims free inode ino is in use, correcting imapThe inode allocation map thinks that inode ino is in use whereas examination of the inode indicatesthat the inode is not in use and therefore is free. The program updates the inode allocation map.resetting inode ino nlinks from x to yThe program detected a mismatch between the number of valid directory entries referencing inode ino andthe number of references recorded in the inode and corrected the the number in the inode.fork-type fork in ino ino claims used block bnoInode ino claims a block bno that is used (claimed) by either another inode or the filesystem itselffor metadata storage. The fork-type is either data or attr indicating whether the problem lies in theportion 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 thefilesystem 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 thefilesystem. The message supplies the start, end, and file offset of the extent. The message isslightly different if the extent is a real-time (rt) extent.bad fork-type fork in inode inoThere was something structurally wrong or inconsistent with the data structures that map offsets tofilesystem blocks.cleared inode inoThere was something wrong with the inode that was uncorrectable so the program freed the inode. Thisusually happens because the inode claims blocks that are used by something else or the inode itself isbadly corrupted. Typically, this message is preceded by one or more messages indicating why the inodeneeded to be cleared.bad attribute fork in inode ino, clearing attr forkThere 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 yThe program found that the number of extents used to store the data in the inode is wrong and correctedthe number. The message refers to nextents if the count is wrong on the number of extents used tostore attribute information.entry name in dir dir_ino not consistent with .. value (xxxx) in dir ino ino, junking entry name in directoryinode dir_inoThe entry name in directory inode dir_ino references a directory inode ino. However, the .. entry indirectory ino does not point back to directory dir_ino, so the program deletes the entry name in direc‐tory inode dir_ino. If the directory inode ino winds up becoming a disconnected inode as a result ofthis, it is moved to lost+found later.entry name in dir dir_ino references already connected dir ino ino, junking entry name in directory inodedir_inoThe entry name in directory inode dir_ino points to a directory inode ino that is known to be a childof another directory. Therefore, the entry is invalid and is deleted. This message refers to an entryin 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 entryAn entry in directory inode dir_ino references an inode ino that is known to be free. The entry istherefore invalid and is deleted. This message refers to a large directory. If the directory weresmall, the message would read "junking entry ...".EXIT STATUSxfs_repair -n (no modify node) will return a status of 1 if filesystem corruption was detected and 0 if nofilesystem corruption was detected. xfs_repair run without the -n option will always return a status code of0.BUGSThe filesystem to be checked and repaired must have been unmounted cleanly using normal system administrationprocedures (the umount(8) command or system shutdown), not as a result of a crash or system reset. If thefilesystem 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 beconsistent, but only the contents of attribute forks that will fit into an inode are checked. This limitationwill be fixed in the future.The no-modify mode (-n option) is not completely accurate. It does not catch inconsistencies in the freespaceand 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 problemsas they are encountered.If a filesystem fails to be repaired, a metadump image can be generated with xfs_metadump(8) and be sent to anXFS maintainer to be analysed and xfs_repair fixed and/or improved.