1 files changed, 7 insertions, 0 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 80bd63738c6d..fa49e900216a 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -31,6 +31,7 @@
 #include <linux/migrate.h>
 #include <linux/ratelimit.h>
 #include <linux/uuid.h>
+#include <linux/semaphore.h>
 #include <asm/unaligned.h>
 #include "compat.h"
 #include "ctree.h"
@@ -2297,6 +2298,7 @@ int open_ctree(struct super_block *sb,
         init_rwsem(&fs_info->extent_commit_sem);
         init_rwsem(&fs_info->cleanup_work_sem);
         init_rwsem(&fs_info->subvol_sem);
+        sema_init(&fs_info->uuid_tree_rescan_sem, 1);
         fs_info->dev_replace.lock_owner = 0;
         atomic_set(&fs_info->dev_replace.nesting_level, 0);
         mutex_init(&fs_info->dev_replace.lock_finishing_cancel_unmount);
@@ -3554,6 +3556,11 @@ int close_ctree(struct btrfs_root *root)
         fs_info->closing = 1;
         smp_mb();
 
+        /* wait for the uuid_scan task to finish */
+        down(&fs_info->uuid_tree_rescan_sem);
+        /* avoid complains from lockdep et al., set sem back to initial state */
+        up(&fs_info->uuid_tree_rescan_sem);
+
         /* pause restriper - we want to resume on mount */
         btrfs_pause_balance(fs_info);