1 files changed, 9 insertions, 0 deletions

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index bb22a4435b2d..08bcfa92a222 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -177,6 +177,15 @@ static int __btrfs_lookup_bio_sums(struct btrfs_root *root,
 
         WARN_ON(bio->bi_vcnt <= 0);
 
+        /*
+         * the free space stuff is only read when it hasn't been
+         * updated in the current transaction.  So, we can safely
+         * read from the commit root and sidestep a nasty deadlock
+         * between reading the free space cache and updating the csum tree.
+         */
+        if (btrfs_is_free_space_inode(root, inode))
+                path->search_commit_root = 1;
+
         disk_bytenr = (u64)bio->bi_sector << 9;
         if (dio)
                 offset = logical_offset;