Btrfs: fix unprotected alloc list insertion during the finishing procedure of replace

the alloc list of the filesystem is protected by ->chunk_mutex, we need
get that mutex when we insert the new device into the list.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/btrfs/dev-replace.c b/fs/btrfs/dev-replace.c
index 564c92638b20..b20d59e5e5dd 100644
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -484,6 +484,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
         WARN_ON(ret);
 
         /* keep away write_all_supers() during the finishing procedure */
+        mutex_lock(&root->fs_info->chunk_mutex);
         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
         btrfs_dev_replace_lock(dev_replace);
         dev_replace->replace_state =
@@ -503,6 +504,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
                               rcu_str_deref(tgt_device->name), scrub_ret);
                 btrfs_dev_replace_unlock(dev_replace);
                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
+                mutex_unlock(&root->fs_info->chunk_mutex);
                 if (tgt_device)
                         btrfs_destroy_dev_replace_tgtdev(fs_info, tgt_device);
                 mutex_unlock(&dev_replace->lock_finishing_cancel_unmount);
@@ -543,6 +545,7 @@ static int btrfs_dev_replace_finishing(struct btrfs_fs_info *fs_info,
          */
         btrfs_dev_replace_unlock(dev_replace);
         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
+        mutex_unlock(&root->fs_info->chunk_mutex);
 
         /* write back the superblocks */
         trans = btrfs_start_transaction(root, 0);