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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-09-25 15:55:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-09-25 15:55:03 -0700 |
| commit | 75467f60a3d14f08f86f2b353298d2826382ff23 (patch) | |
| tree | acd8a7d5b5a675042449386efa5b42ec44d8bf81 /Documentation/admin-guide/device-mapper/linear.rst | |
| download | linux-stable-75467f60a3d14f08f86f2b353298d2826382ff23.tar.gz linux-stable-75467f60a3d14f08f86f2b353298d2826382ff23.zip | |
Merge tag 'ipe-pr-20260925' of git://git.kernel.org/pub/scm/linux/kernel/git/wufan/ipegrafted
Pull IPE fixes from Fan Wu:
"Two fixes for use-after-free issues found by recent LLM-assisted code
analysis.
- move successful policy load auditing under the new policy
directory's inode lock, preventing a concurrent policy deletion
from freeing the policy while it is still being audited
- protect the dm-verity root hash with RCU, preventing policy
evaluation from racing with root hash replacement during preresume"
* tag 'ipe-pr-20260925' of git://git.kernel.org/pub/scm/linux/kernel/git/wufan/ipe:
ipe: protect the dm-verity root hash with RCU
ipe: fix use-after-free when auditing a newly loaded policy
Diffstat (limited to 'Documentation/admin-guide/device-mapper/linear.rst')
| -rw-r--r-- | Documentation/admin-guide/device-mapper/linear.rst | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/Documentation/admin-guide/device-mapper/linear.rst b/Documentation/admin-guide/device-mapper/linear.rst new file mode 100644 index 000000000..9d17fc6e6 --- /dev/null +++ b/Documentation/admin-guide/device-mapper/linear.rst @@ -0,0 +1,63 @@ +========= +dm-linear +========= + +Device-Mapper's "linear" target maps a linear range of the Device-Mapper +device onto a linear range of another device. This is the basic building +block of logical volume managers. + +Parameters: <dev path> <offset> + <dev path>: + Full pathname to the underlying block-device, or a + "major:minor" device-number. + <offset>: + Starting sector within the device. + + +Example scripts +=============== + +:: + + #!/bin/sh + # Create an identity mapping for a device + echo "0 `blockdev --getsz $1` linear $1 0" | dmsetup create identity + +:: + + #!/bin/sh + # Join 2 devices together + size1=`blockdev --getsz $1` + size2=`blockdev --getsz $2` + echo "0 $size1 linear $1 0 + $size1 $size2 linear $2 0" | dmsetup create joined + +:: + + #!/usr/bin/perl -w + # Split a device into 4M chunks and then join them together in reverse order. + + my $name = "reverse"; + my $extent_size = 4 * 1024 * 2; + my $dev = $ARGV[0]; + my $table = ""; + my $count = 0; + + if (!defined($dev)) { + die("Please specify a device.\n"); + } + + my $dev_size = `blockdev --getsz $dev`; + my $extents = int($dev_size / $extent_size) - + (($dev_size % $extent_size) ? 1 : 0); + + while ($extents > 0) { + my $this_start = $count * $extent_size; + $extents--; + $count++; + my $this_offset = $extents * $extent_size; + + $table .= "$this_start $extent_size linear $dev $this_offset\n"; + } + + `echo \"$table\" | dmsetup create $name`; |
