From: Miao Xie <miaox@cn.fujitsu.com>
Date: Tue, 22 Jan 2013 10:52:04 +0000 (+0000)
Subject: Btrfs: don't traverse the ordered operation list repeatedly
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=5b947f1ba959d4b19068f687ecd39900d1eea1aa;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

Btrfs: don't traverse the ordered operation list repeatedly

btrfs_run_ordered_operations() needn't traverse the ordered operation list
repeatedly, it is because the transaction commiter will invoke it again when
there is no other writer in this transaction, it can ensure that no one can
add new objects into the ordered operation list.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
---

diff --git a/fs/btrfs/ordered-data.c b/fs/btrfs/ordered-data.c
index f14b17432117..9489fa96e3ed 100644
--- a/fs/btrfs/ordered-data.c
+++ b/fs/btrfs/ordered-data.c
@@ -626,14 +626,10 @@ int btrfs_run_ordered_operations(struct btrfs_root *root, int wait)
 
 	mutex_lock(&root->fs_info->ordered_operations_mutex);
 	spin_lock(&root->fs_info->ordered_extent_lock);
-again:
 	list_splice_init(&root->fs_info->ordered_operations, &splice);
-
 	while (!list_empty(&splice)) {
-
 		btrfs_inode = list_entry(splice.next, struct btrfs_inode,
 				   ordered_operations);
-
 		inode = &btrfs_inode->vfs_inode;
 
 		list_del_init(&btrfs_inode->ordered_operations);
@@ -642,22 +638,20 @@ again:
 		 * the inode may be getting freed (in sys_unlink path).
 		 */
 		inode = igrab(inode);
-
-		if (!wait && inode) {
-			list_add_tail(&BTRFS_I(inode)->ordered_operations,
-			      &root->fs_info->ordered_operations);
-		}
-
 		if (!inode)
 			continue;
+
+		if (!wait)
+			list_add_tail(&BTRFS_I(inode)->ordered_operations,
+				      &root->fs_info->ordered_operations);
 		spin_unlock(&root->fs_info->ordered_extent_lock);
 
 		work = btrfs_alloc_delalloc_work(inode, wait, 1);
 		if (!work) {
+			spin_lock(&root->fs_info->ordered_extent_lock);
 			if (list_empty(&BTRFS_I(inode)->ordered_operations))
 				list_add_tail(&btrfs_inode->ordered_operations,
 					      &splice);
-			spin_lock(&root->fs_info->ordered_extent_lock);
 			list_splice_tail(&splice,
 					 &root->fs_info->ordered_operations);
 			spin_unlock(&root->fs_info->ordered_extent_lock);
@@ -671,9 +665,6 @@ again:
 		cond_resched();
 		spin_lock(&root->fs_info->ordered_extent_lock);
 	}
-	if (wait && !list_empty(&root->fs_info->ordered_operations))
-		goto again;
-
 	spin_unlock(&root->fs_info->ordered_extent_lock);
 out:
 	list_for_each_entry_safe(work, next, &works, list) {