@@ -733,6 +733,32 @@ static struct btrfs_fs_devices *find_fsid_changed(
return NULL;
}
+
+static struct btrfs_fs_devices *find_fsid_reverted_metadata(
+ struct btrfs_super_block *disk_super)
+{
+ struct btrfs_fs_devices *fs_devices;
+
+ /*
+ * Handles the case where the scanned device is part of an fs whose last
+ * metadata uuid change reverted it to the original FSID. At the same time
+ * fs_devices was first created by another constitutent device which didn't
+ * fully observer the operation. This results in an btrfs_fs_devices
+ * created with metadata/fsid different AND btrfs_fs_devices::fsid_change
+ * set AND the metadata_uuid of the fs_devices equal to the FSID of the
+ * disk.
+ */
+ list_for_each_entry(fs_devices, &fs_uuids, fs_list) {
+ if (memcmp(fs_devices->fsid, fs_devices->metadata_uuid,
+ BTRFS_FSID_SIZE) != 0 &&
+ memcmp(fs_devices->metadata_uuid, disk_super->fsid,
+ BTRFS_FSID_SIZE) == 0 &&
+ fs_devices->fsid_change)
+ return fs_devices;
+ }
+
+ return NULL;
+}
/*
* Add new device to list of registered devices
*
@@ -762,7 +788,9 @@ static noinline struct btrfs_device *device_list_add(const char *path,
} else if (has_metadata_uuid) {
fs_devices = find_fsid_with_metadata_uuid(disk_super);
} else {
- fs_devices = find_fsid(disk_super->fsid, NULL);
+ fs_devices = find_fsid_reverted_metadata(disk_super);
+ if (!fs_devices)
+ fs_devices = find_fsid(disk_super->fsid, NULL);
}
@@ -792,12 +820,17 @@ static noinline struct btrfs_device *device_list_add(const char *path,
* a device which had the CHANGING_FSID_V2 flag then replace the
* metadata_uuid/fsid values of the fs_devices.
*/
- if (has_metadata_uuid && fs_devices->fsid_change &&
+ if (fs_devices->fsid_change &&
found_transid > fs_devices->latest_generation) {
memcpy(fs_devices->fsid, disk_super->fsid,
BTRFS_FSID_SIZE);
- memcpy(fs_devices->metadata_uuid,
- disk_super->metadata_uuid, BTRFS_FSID_SIZE);
+
+ if (has_metadata_uuid)
+ memcpy(fs_devices->metadata_uuid,
+ disk_super->metadata_uuid, BTRFS_FSID_SIZE);
+ else
+ memcpy(fs_devices->metadata_uuid,
+ disk_super->fsid, BTRFS_FSID_SIZE);
fs_devices->fsid_change = false;
}
Current code doesn't correctly handle the situation which arises when a file system that has METADATA_UUID_INCOMPAT flag set has its FSID changed to the one in metadata uuid. This causes the incompat flag to disappear. In case of a power failure we could end up in a situation where part of the disks in a multi-disk filesystem are correctly reverted to METADATA_UUID_INCOMPAT flag unset state, while others have METADATA_UUID_INCOMPAT set and CHANGING_FSID_V2_IN_PROGRESS. This patch corrects the behavior required to handle the case where a disk of the second type is scanned first, creating the necessary btrfs_fs_devices. Subsequently, when a disk which has already completed the transition is scanned it should overwrite the data in btrfs_fs_devices. Reported-by: Su Yue <Damenly_Su@gmx.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> --- fs/btrfs/volumes.c | 41 +++++++++++++++++++++++++++++++++++++---- 1 file changed, 37 insertions(+), 4 deletions(-) -- 2.17.1