Btrfs: don't wait on uptodate buffers on read

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 39b117a57a54..055cd45e802e 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -214,6 +214,8 @@ struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr)
         bh = btrfs_find_create_tree_block(root, blocknr);
         if (!bh)
                 return bh;
+        if (buffer_uptodate(bh))
+                goto uptodate;
         lock_buffer(bh);
         if (!buffer_uptodate(bh)) {
                 get_bh(bh);
@@ -226,6 +228,7 @@ struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr)
         } else {
                 unlock_buffer(bh);
         }
+uptodate:
         if (check_tree_block(root, bh))
                 BUG();
         return bh;