xfs_bmap(8) — Linux manual page


xfs_bmap(8)                System Manager's Manual               xfs_bmap(8)

NAME         top

       xfs_bmap - print block mapping for an XFS file

SYNOPSIS         top

       xfs_bmap [ -adelpv ] [ -n num_extents ] file
       xfs_bmap -V

DESCRIPTION         top

       xfs_bmap prints the map of disk blocks used by files in an XFS
       filesystem.  The map lists each extent used by the file, as well as
       regions in the file that do not have any corresponding blocks
       (holes).  Each line of the listings takes the following form:

              extent: [startoffset..endoffset]: startblock..endblock

       Holes are marked by replacing the startblock..endblock with hole.
       All the file offsets and disk blocks are in units of 512-byte blocks,
       no matter what the filesystem's block size is.

OPTIONS         top

       -a     If this option is specified, information about the file's
              attribute fork is printed instead of the default data fork.

       -d     If portions of the file have been migrated offline by a DMAPI
              application, a DMAPI read event will be generated to bring
              those portions back online before the disk block map is
              printed.  However if the -d option is used, no DMAPI read
              event will be generated for a DMAPI file and offline portions
              will be reported as holes.

       -e     If this option is used, xfs_bmap obtains all delayed
              allocation extents, and does not flush dirty pages to disk
              before querying extent data. With the -v option, the flags
              column will show which extents have not yet been allocated.

       -l     If this option is used, then

                   <nblocks>  blocks

              will be appended to each line.  nblocks is the length of the
              extent described on the line in units of 512-byte blocks.

              This flag has no effect if the -v option is used.

       -n num_extents
              If this option is given, xfs_bmap will display at most
              num_extents extents. In the absence of -n, xfs_bmap will
              display all extents in the file.

       -p     If this option is used, xfs_bmap obtains all unwritten
              (preallocated) extents that do not contain written data. With
              the -v option, the flags column will show which extents are

       -v     Shows verbose information. When this flag is specified,
              additional AG specific information is appended to each line in
              the following form:

                   agno (startagoffset..endagoffset) nblocks flags

              A second -v option will print out the flags legend.

       -V     Prints the version number and exits.

SEE ALSO         top

       xfs_fsr(8), xfs(5).

COLOPHON         top

       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 linux-xfs@vger.kernel.org.  This page was obtained from
       the project's upstream Git repository
       ⟨https://git.kernel.org/pub/scm/fs/xfs/xfsprogs-dev.git⟩ on
       2020-09-18.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-09-04.)  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


Pages that refer to this page: xfs_io(8)