From 5124e00ec5b0be56155a11aec416fcc5125339f1 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@fusionio.com>
Date: Wed, 7 Nov 2012 13:44:13 -0500
Subject: [PATCH] Btrfs: only unlock and relock if we have to
I noticed while doing fsync tests that we were always dropping the path and
re-searching when we first cow the log root even though we've already gotten
the write lock on the root. That's because we don't take into account that
there might not be a parent node, so fix the check to make sure there is
actually a parent node before we undo all of this work for nothing. Thanks,
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
---
fs/btrfs/ctree.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index e7bea1d5f75fd..c7b67cf24bba5 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2564,7 +2564,10 @@ int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root
* must have write locks on this node and the
* parent
*/
- if (level + 1 > write_lock_level) {
+ if (level > write_lock_level ||
+ (level + 1 > write_lock_level &&
+ level + 1 < BTRFS_MAX_LEVEL &&
+ p->nodes[level + 1])) {
write_lock_level = level + 1;
btrfs_release_path(p);
goto again;