diff options
| author | Anand Jain <anand.jain@oracle.com> | 2024-03-01 08:42:13 +0800 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2024-03-26 16:42:38 +0100 |
| commit | 9f7eb8405dcbc79c5434821e9e3e92abe187ee8e (patch) | |
| tree | 7f99d51bf300140ba4bcf413930e2a2e8692eb52 | |
| parent | 1ec17ef59168a1a6f1105f5dc517f783839a5302 (diff) | |
| download | linux-9f7eb8405dcbc79c5434821e9e3e92abe187ee8e.tar.gz | |
btrfs: validate device maj:min during open
Boris managed to create a device capable of changing its maj:min without
altering its device path.
Only multi-devices can be scanned. A device that gets scanned and remains
in the btrfs kernel cache might end up with an incorrect maj:min.
Despite the temp-fsid feature patch did not introduce this bug, it could
lead to issues if the above multi-device is converted to a single device
with a stale maj:min. Subsequently, attempting to mount the same device
with the correct maj:min might mistake it for another device with the same
fsid, potentially resulting in wrongly auto-enabling the temp-fsid feature.
To address this, this patch validates the device's maj:min at the time of
device open and updates it if it has changed since the last scan.
CC: stable@vger.kernel.org # 6.7+
Fixes: a5b8a5f9f835 ("btrfs: support cloned-device mount capability")
Reported-by: Boris Burkov <boris@bur.io>
Co-developed-by: Boris Burkov <boris@bur.io>
Reviewed-by: Boris Burkov <boris@bur.io>#
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/volumes.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index e49935a54da0a..c318640b4472a 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -692,6 +692,16 @@ static int btrfs_open_one_device(struct btrfs_fs_devices *fs_devices, device->bdev = bdev_handle->bdev; clear_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &device->dev_state); + if (device->devt != device->bdev->bd_dev) { + btrfs_warn(NULL, + "device %s maj:min changed from %d:%d to %d:%d", + device->name->str, MAJOR(device->devt), + MINOR(device->devt), MAJOR(device->bdev->bd_dev), + MINOR(device->bdev->bd_dev)); + + device->devt = device->bdev->bd_dev; + } + fs_devices->open_devices++; if (test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state) && device->devid != BTRFS_DEV_REPLACE_DEVID) { |