[V2,05/10] Btrfs: remove unnecessary lock in may_commit_transaction()

Commit Message

Miao Xie March 6, 2014, 5:54 a.m. UTC

The reason is:
- The per-cpu counter has its own lock to protect itself.
- Here we needn't get a exact value.

Signed-off-by: Miao Xie <[e-mail]>
---
Changelog v1 -> v2:
- None.
---
 fs/btrfs/extent-tree.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

Patch

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 32312e0..ddb5c84 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4112,13 +4112,9 @@  static int may_commit_transaction(struct btrfs_root *root,
 		goto commit;
 
 	/* See if there is enough pinned space to make this reservation */
-	spin_lock(&space_info->lock);
 	if (percpu_counter_compare(&space_info->total_bytes_pinned,
-				   bytes) >= 0) {
-		spin_unlock(&space_info->lock);
+				   bytes) >= 0)
 		goto commit;
-	}
-	spin_unlock(&space_info->lock);
 
 	/*
 	 * See if there is some space in the delayed insertion reservation for
@@ -4127,16 +4123,13 @@  static int may_commit_transaction(struct btrfs_root *root,
 	if (space_info != delayed_rsv->space_info)
 		return -ENOSPC;
 
-	spin_lock(&space_info->lock);
 	spin_lock(&delayed_rsv->lock);
 	if (percpu_counter_compare(&space_info->total_bytes_pinned,
 				   bytes - delayed_rsv->size) >= 0) {
 		spin_unlock(&delayed_rsv->lock);
-		spin_unlock(&space_info->lock);
 		return -ENOSPC;
 	}
 	spin_unlock(&delayed_rsv->lock);
-	spin_unlock(&space_info->lock);
 
 commit:
 	trans = btrfs_join_transaction(root);