9p: fix fid refcount leak in v9fs_vfs_atomic_open_dotl

We need to release directory fid if we fail halfway through open

This fixes fid leaking with xfstests generic 531

Link: https://lkml.kernel.org/r/20220612085330.1451496-2-asmadeus@codewreck.org
Fixes: 6636b6d ("9p: add refcount to p9_fid struct")
Cc: stable@vger.kernel.org
Reported-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>

Author: martinetd

fs/9p/vfs_inode_dotl.c

@@ -274,6 +274,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
 	if (IS_ERR(ofid)) {
 		err = PTR_ERR(ofid);
 		p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
+		p9_client_clunk(dfid);
 		goto out;
 	}
 
@@ -285,13 +286,15 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct dentry *dentry,
 	if (err) {
 		p9_debug(P9_DEBUG_VFS, "Failed to get acl values in creat %d\n",
 			 err);
+		p9_client_clunk(dfid);
 		goto error;
 	}
 	err = p9_client_create_dotl(ofid, name, v9fs_open_to_dotl_flags(flags),
 				    mode, gid, &qid);
 	if (err < 0) {
 		p9_debug(P9_DEBUG_VFS, "p9_client_open_dotl failed in creat %d\n",
 			 err);
+		p9_client_clunk(dfid);
 		goto error;
 	}
 	v9fs_invalidate_inode_attr(dir);