xfs_bmap - print block mapping for an XFS file

xfs_bmap [ -a ] [ -l ] [ -d ] [ -n nnn ] file ...

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]: c
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.

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.

If the -l 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.

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

If the -n nnn option is given, xfs_bmap obtains the extent list of the file in groups of nnn extents. In the absence of -n, xfs_bmap queries the system for the number of extents in the file and uses that value to compute the group size.

xfs(5).