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: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
This commit is contained in:
Miao Xie 2014-03-06 13:54:55 +08:00 committed by Josef Bacik
parent 8257b2dc3c
commit 8b9d83cd6b

View File

@ -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);
}
/*