[PATCH 1/3] btrfs: run delayed iputs before committing

[Josef Bacik <josef@toxicpanda.com>]

Delayed iputs means we can have final iputs of deleted inodes in the
queue, which could potentially generate a lot of pinned space that could
be free'd.  So before we decide to commit the transaction for ENOPSC
reasons, run the delayed iputs so that any potential space is free'd up.
If there is and we freed enough we can then commit the transaction and
potentially be able to make our reservation.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
---
 fs/btrfs/extent-tree.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 90423b6749b7..3a90dc1d6b31 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4833,6 +4833,15 @@ static int may_commit_transaction(struct btrfs_fs_info *fs_info,
 	if (!bytes)
 		return 0;
 
+	/*
+	 * If we have pending delayed iputs then we could free up a bunch of
+	 * pinned space, so make sure we run the iputs before we do our pinned
+	 * bytes check below.
+	 */
+	mutex_lock(&fs_info->cleaner_delayed_iput_mutex);
+	btrfs_run_delayed_iputs(fs_info);
+	mutex_unlock(&fs_info->cleaner_delayed_iput_mutex);
+
 	trans = btrfs_join_transaction(fs_info->extent_root);
 	if (IS_ERR(trans))
 		return PTR_ERR(trans);
-- 
2.14.3