btrfs: reduce uuid_mutex critical section while scanning devices
The generic block device lookup or cleanup does not need the uuid mutex,
that's only for the device_list_add.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index ebc8176..c1d09da 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1232,31 +1232,29 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
*/
bytenr = btrfs_sb_offset(0);
flags |= FMODE_EXCL;
- mutex_lock(&uuid_mutex);
bdev = blkdev_get_by_path(path, flags, holder);
- if (IS_ERR(bdev)) {
- ret = PTR_ERR(bdev);
- goto error;
- }
+ if (IS_ERR(bdev))
+ return PTR_ERR(bdev);
if (btrfs_read_disk_super(bdev, bytenr, &page, &disk_super)) {
ret = -EINVAL;
goto error_bdev_put;
}
+ mutex_lock(&uuid_mutex);
device = device_list_add(path, disk_super);
if (IS_ERR(device))
ret = PTR_ERR(device);
else
*fs_devices_ret = device->fs_devices;
+ mutex_unlock(&uuid_mutex);
btrfs_release_disk_super(page);
error_bdev_put:
blkdev_put(bdev, flags);
-error:
- mutex_unlock(&uuid_mutex);
+
return ret;
}