btrfs: Adjust commit-transaction condition to avoid NO_SPACE more

If we have any chance to make a successful write, we should not give up.

This patch adjust commit-transaction condition from:
  pinned >= wanted
to
  left + pinned >= wanted

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 7b227a65078c..01f4db6554a1 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3931,7 +3931,8 @@ alloc:
                  * don't bother committing the transaction.
                  */
                 if (percpu_counter_compare(&data_sinfo->total_bytes_pinned,
-                                           bytes) < 0)
+                                           used + bytes -
+                                           data_sinfo->total_bytes) < 0)
                         have_pinned_space = 0;
                 spin_unlock(&data_sinfo->lock);