xfs_bmap
Section: Maintenance Commands (8)
Page Index
NAME
xfs_bmap - print block mapping for an XFS file
SYNOPSIS
xfs_bmap
[
-adelpv
] [
-n
num_extents
]
file
xfs_bmap -V
DESCRIPTION
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
- -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 preallocated/unwritten.
- -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
xfs_fsr(8),
xfs(5).