Commit 8b9d83cd authored by Miao Xie's avatar Miao Xie Committed by Josef Bacik
Browse files

Btrfs: fix early enospc due to the race of the two ordered extent wait 



btrfs_wait_ordered_roots() moves all the list entries to a new list,
and then deals with them one by one. But if the other task invokes this
function at that time, it would get a empty list. It makes the enospc
error happens more early. Fix it.

Signed-off-by: default avatarMiao Xie <miaox@cn.fujitsu.com>
Signed-off-by: default avatarJosef Bacik <jbacik@fb.com>
parent 8257b2dc

fs/btrfs/ordered-data.c

+14 −3
Original line number Diff line number Diff line
@@ -589,7 +589,7 @@ static void btrfs_run_ordered_extent_work(struct btrfs_work *work) 
 * wait for all the ordered extents in a root.  This is done when balancing

 * space between drives.

 */

int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)

static int __btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)

{

	struct list_head splice, works;

	struct btrfs_ordered_extent *ordered, *next;
@@ -598,7 +598,6 @@ int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr) 
	INIT_LIST_HEAD(&splice);

	INIT_LIST_HEAD(&works);



	mutex_lock(&root->fs_info->ordered_operations_mutex);

	spin_lock(&root->ordered_extent_lock);

	list_splice_init(&root->ordered_extents, &splice);

	while (!list_empty(&splice) && nr) {
@@ -630,6 +629,16 @@ int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr) 
		btrfs_put_ordered_extent(ordered);

		cond_resched();

	}



	return count;

}



int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)

{

	int count;



	mutex_lock(&root->fs_info->ordered_operations_mutex);

	count = __btrfs_wait_ordered_extents(root, nr);

	mutex_unlock(&root->fs_info->ordered_operations_mutex);



	return count;
@@ -643,6 +652,7 @@ void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr) 


	INIT_LIST_HEAD(&splice);



	mutex_lock(&fs_info->ordered_operations_mutex);

	spin_lock(&fs_info->ordered_root_lock);

	list_splice_init(&fs_info->ordered_roots, &splice);

	while (!list_empty(&splice) && nr) {
@@ -654,7 +664,7 @@ void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr) 
			       &fs_info->ordered_roots);

		spin_unlock(&fs_info->ordered_root_lock);



		done = btrfs_wait_ordered_extents(root, nr);

		done = __btrfs_wait_ordered_extents(root, nr);

		btrfs_put_fs_root(root);



		spin_lock(&fs_info->ordered_root_lock);
@@ -665,6 +675,7 @@ void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr) 
	}

	list_splice_tail(&splice, &fs_info->ordered_roots);

	spin_unlock(&fs_info->ordered_root_lock);

	mutex_unlock(&fs_info->ordered_operations_mutex);

}



/*

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