Commit f7361d8c authored by Anand Jain's avatar Anand Jain Committed by David Sterba
Browse files

btrfs: sipmlify uuid parameters of alloc_fs_devices() 



Among all the callers, only the device_list_add() function uses the
second argument of alloc_fs_devices(). It passes metadata_uuid when
available, otherwise, it passes NULL. And in turn, alloc_fs_devices()
is designed to copy either metadata_uuid or fsid into
fs_devices::metadata_uuid.

So remove the second argument in alloc_fs_devices(), and always copy the
fsid.  In the caller device_list_add() function, we will overwrite it
with metadata_uuid when it is available.

Signed-off-by: default avatarAnand Jain <anand.jain@oracle.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 01fc062b

fs/btrfs/disk-io.c

+4 −3
Original line number Diff line number Diff line
@@ -318,9 +318,10 @@ static bool check_tree_block_fsid(struct extent_buffer *eb) 
			   BTRFS_FSID_SIZE);



	/*

	 * alloc_fs_devices() copies the fsid into metadata_uuid if the

	 * metadata_uuid is unset in the superblock, including for a seed device.

	 * So, we can use fs_devices->metadata_uuid.

	 * alloc_fsid_devices() copies the fsid into fs_devices::metadata_uuid.

	 * This is then overwritten by metadata_uuid if it is present in the

	 * device_list_add(). The same true for a seed device as well. So use of

	 * fs_devices::metadata_uuid is appropriate here.

	 */

	if (memcmp(fsid, fs_info->fs_devices->metadata_uuid, BTRFS_FSID_SIZE) == 0)

		return false;

fs/btrfs/volumes.c

+14 −14
Original line number Diff line number Diff line
@@ -357,21 +357,19 @@ struct list_head * __attribute_const__ btrfs_get_fs_uuids(void) 
}



/*

 * alloc_fs_devices - allocate struct btrfs_fs_devices

 * @fsid:		if not NULL, copy the UUID to fs_devices::fsid

 * @metadata_fsid:	if not NULL, copy the UUID to fs_devices::metadata_fsid

 * Allocate new btrfs_fs_devices structure identified by a fsid.

 *

 * @fsid:    if not NULL, copy the UUID to fs_devices::fsid and to

 *           fs_devices::metadata_fsid

 *

 * Return a pointer to a new struct btrfs_fs_devices on success, or ERR_PTR().

 * The returned struct is not linked onto any lists and can be destroyed with

 * kfree() right away.

 */

static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid,

						 const u8 *metadata_fsid)

static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid)

{

	struct btrfs_fs_devices *fs_devs;



	ASSERT(fsid || !metadata_fsid);



	fs_devs = kzalloc(sizeof(*fs_devs), GFP_KERNEL);

	if (!fs_devs)

		return ERR_PTR(-ENOMEM);
@@ -385,8 +383,7 @@ static struct btrfs_fs_devices *alloc_fs_devices(const u8 *fsid, 


	if (fsid) {

		memcpy(fs_devs->fsid, fsid, BTRFS_FSID_SIZE);

		memcpy(fs_devs->metadata_uuid,

		       metadata_fsid ?: fsid, BTRFS_FSID_SIZE);

		memcpy(fs_devs->metadata_uuid, fsid, BTRFS_FSID_SIZE);

	}



	return fs_devs;
@@ -812,8 +809,11 @@ static noinline struct btrfs_device *device_list_add(const char *path, 




	if (!fs_devices) {

		fs_devices = alloc_fs_devices(disk_super->fsid,

				has_metadata_uuid ? disk_super->metadata_uuid : NULL);

		fs_devices = alloc_fs_devices(disk_super->fsid);

		if (has_metadata_uuid)

			memcpy(fs_devices->metadata_uuid,

			       disk_super->metadata_uuid, BTRFS_FSID_SIZE);



		if (IS_ERR(fs_devices))

			return ERR_CAST(fs_devices);
@@ -997,7 +997,7 @@ static struct btrfs_fs_devices *clone_fs_devices(struct btrfs_fs_devices *orig) 


	lockdep_assert_held(&uuid_mutex);



	fs_devices = alloc_fs_devices(orig->fsid, NULL);

	fs_devices = alloc_fs_devices(orig->fsid);

	if (IS_ERR(fs_devices))

		return fs_devices;
@@ -2451,7 +2451,7 @@ static struct btrfs_fs_devices *btrfs_init_sprout(struct btrfs_fs_info *fs_info) 
	 * Private copy of the seed devices, anchored at

	 * fs_info->fs_devices->seed_list

	 */

	seed_devices = alloc_fs_devices(NULL, NULL);

	seed_devices = alloc_fs_devices(NULL);

	if (IS_ERR(seed_devices))

		return seed_devices;
@@ -6901,7 +6901,7 @@ static struct btrfs_fs_devices *open_seed_devices(struct btrfs_fs_info *fs_info, 
		if (!btrfs_test_opt(fs_info, DEGRADED))

			return ERR_PTR(-ENOENT);



		fs_devices = alloc_fs_devices(fsid, NULL);

		fs_devices = alloc_fs_devices(fsid);

		if (IS_ERR(fs_devices))

			return fs_devices;