ceph: do not chain inode updates to parent fsync

The fsync(dirfd) only covers namespace operations, not inode updates.
We do not need to cover setattr variants or O_TRUNC.

Reported-by: Al Viro <viro@xeniv.linux.org.uk>
Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 32d519d..8bf2384 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1627,7 +1627,6 @@
 {
 	struct inode *inode = dentry->d_inode;
 	struct ceph_inode_info *ci = ceph_inode(inode);
-	struct inode *parent_inode;
 	const unsigned int ia_valid = attr->ia_valid;
 	struct ceph_mds_request *req;
 	struct ceph_mds_client *mdsc = ceph_sb_to_client(dentry->d_sb)->mdsc;
@@ -1819,9 +1818,7 @@
 		req->r_inode_drop = release;
 		req->r_args.setattr.mask = cpu_to_le32(mask);
 		req->r_num_caps = 1;
-		parent_inode = ceph_get_dentry_parent_inode(dentry);
-		err = ceph_mdsc_do_request(mdsc, parent_inode, req);
-		iput(parent_inode);
+		err = ceph_mdsc_do_request(mdsc, NULL, req);
 	}
 	dout("setattr %p result=%d (%s locally, %d remote)\n", inode, err,
 	     ceph_cap_string(dirtied), mask);