diff options
| author | Boris Burkov <boris@bur.io> | 2024-03-11 12:13:44 -0700 |
|---|---|---|
| committer | Zorro Lang <zlang@kernel.org> | 2024-04-28 19:08:22 +0800 |
| commit | bc9debb83c9867b2cdfd19e3a304616749f1912c (patch) | |
| tree | 5460d1a6b85b3dd3d9cf42b8081d04fc012f6b64 /common | |
| parent | b9785de77fcb7b4c9f58d6d7178a0ef63a059b84 (diff) | |
btrfs: new test for devt change between mounts
It is possible to confuse the btrfs device cache (fs_devices) by
starting with a multi-device filesystem, then removing and re-adding a
device in a way which changes its dev_t while the filesystem is
unmounted. After this procedure, if we remount, then we are in a funny
state where struct btrfs_device's "devt" field does not match the bd_dev
of the "bdev" field. I would say this is bad enough, as we have violated
a pretty clear invariant.
But for style points, we can then remove the extra device from the fs,
making it a single device fs, which enables the "temp_fsid" feature,
which permits multiple separate mounts of different devices with the
same fsid. Since btrfs is confused and *thinks* there are different
devices (based on device->devt), it allows a second redundant mount of
the same device (not a bind mount!). This then allows us to corrupt the
original mount by doing stuff to the one that should be a bind mount.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Boris Burkov <boris@bur.io>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
[ use _create_loop_device, renamed $MNT $BIND and rm them before mkdir ]
Signed-off-by: Zorro Lang <zlang@kernel.org>
[ update the commit id of _fixed_by_kernel_commit ]
Diffstat (limited to 'common')
| -rw-r--r-- | common/config | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/common/config b/common/config index 6a0496fd..eac0710e 100644 --- a/common/config +++ b/common/config @@ -235,6 +235,7 @@ export BLKZONE_PROG="$(type -P blkzone)" export GZIP_PROG="$(type -P gzip)" export BTRFS_IMAGE_PROG="$(type -P btrfs-image)" export BTRFS_MAP_LOGICAL_PROG=$(type -P btrfs-map-logical) +export PARTED_PROG="$(type -P parted)" # use 'udevadm settle' or 'udevsettle' to wait for lv to be settled. # newer systems have udevadm command but older systems like RHEL5 don't. |