1 files changed, 10 insertions, 0 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index c86fb5438454..6f49b2872a64 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1000,6 +1000,16 @@ int btrfs_sync_fs(struct super_block *sb, int wait)
                          */
                         if (fs_info->pending_changes == 0)
                                 return 0;
+                        /*
+                         * A non-blocking test if the fs is frozen. We must not
+                         * start a new transaction here otherwise a deadlock
+                         * happens. The pending operations are delayed to the
+                         * next commit after thawing.
+                         */
+                        if (__sb_start_write(sb, SB_FREEZE_WRITE, false))
+                                __sb_end_write(sb, SB_FREEZE_WRITE);
+                        else
+                                return 0;
                         trans = btrfs_start_transaction(root, 0);
                 }
                 if (IS_ERR(trans))