Btrfs: Integrate metadata reservation with start_transaction

Besides simplify the code, this change makes sure all metadata
reservation for normal metadata operations are released after
committing transaction.

Changes since V1:

Add code that check if unlink and rmdir will free space.

Add ENOSPC handling for clone ioctl.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 3 insertions, 9 deletions

diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index 193b58f7d3f3..007fae581a04 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -154,15 +154,10 @@ int __btrfs_setxattr(struct btrfs_trans_handle *trans,
         if (trans)
                 return do_setxattr(trans, inode, name, value, size, flags);
 
-        ret = btrfs_reserve_metadata_space(root, 2);
-        if (ret)
-                return ret;
+        trans = btrfs_start_transaction(root, 2);
+        if (IS_ERR(trans))
+                return PTR_ERR(trans);
 
-        trans = btrfs_start_transaction(root, 1);
-        if (!trans) {
-                ret = -ENOMEM;
-                goto out;
-        }
         btrfs_set_trans_block_group(trans, inode);
 
         ret = do_setxattr(trans, inode, name, value, size, flags);
@@ -174,7 +169,6 @@ int __btrfs_setxattr(struct btrfs_trans_handle *trans,
         BUG_ON(ret);
 out:
         btrfs_end_transaction_throttle(trans, root);
-        btrfs_unreserve_metadata_space(root, 2);
         return ret;
 }