Btrfs: move d_instantiate outside the transaction during mksubvol

Dave Sterba triggered a lockdep complaint about lock ordering
between the sb_internal lock and the cleaner semaphore.

btrfs_lookup_dentry() checks for orphans if we're looking up
the inode for a subvolume, and subvolume creation is triggering
the lookup with a transaction running.

This commit moves the d_instantiate after the transaction closes.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index afbf3ac2079d..a31cd931d36e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -515,7 +515,6 @@ static noinline int create_subvol(struct btrfs_root *root,
 
         BUG_ON(ret);
 
-        d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
 fail:
         if (async_transid) {
                 *async_transid = trans->transid;
@@ -525,6 +524,10 @@ fail:
         }
         if (err && !ret)
                 ret = err;
+
+        if (!ret)
+                d_instantiate(dentry, btrfs_lookup_dentry(dir, dentry));
+
         return ret;
 }