Btrfs: fix sleep with spinlock held during unmount
The code to free block groups needs to drop the space info spin lock
before calling btrfs_remove_free_space_cache (which can schedule).
This is safe because at unmount time, nobody else is going to play
with the block groups.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 5258923..fe4e11b 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3157,9 +3157,13 @@
block_group = rb_entry(n, struct btrfs_block_group_cache,
cache_node);
+ spin_unlock(&info->block_group_cache_lock);
btrfs_remove_free_space_cache(block_group);
+ spin_lock(&info->block_group_cache_lock);
+
rb_erase(&block_group->cache_node,
&info->block_group_cache_tree);
+
spin_lock(&block_group->space_info->lock);
list_del(&block_group->list);
spin_unlock(&block_group->space_info->lock);