Btrfs: fix block_rsv and space_info lock ordering

may_commit_transaction() calls
        spin_lock(&space_info->lock);
        spin_lock(&delayed_rsv->lock);
and update_global_block_rsv() calls
        spin_lock(&block_rsv->lock);
        spin_lock(&sinfo->lock);

Lockdep complains about this at run time.
Everywhere except in update_global_block_rsv(), the space_info lock is
the outer lock, therefore the locking order in update_global_block_rsv()
is changed.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 84497f8eb043..6fc2e6f5aab8 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -4214,8 +4214,8 @@ static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
 
         num_bytes = calc_global_metadata_size(fs_info);
 
-        spin_lock(&block_rsv->lock);
         spin_lock(&sinfo->lock);
+        spin_lock(&block_rsv->lock);
 
         block_rsv->size = num_bytes;
 
@@ -4241,8 +4241,8 @@ static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
                 block_rsv->full = 1;
         }
 
-        spin_unlock(&sinfo->lock);
         spin_unlock(&block_rsv->lock);
+        spin_unlock(&sinfo->lock);
 }
 
 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)