ceph: use ihold when we already have an inode ref

We should use ihold whenever we already have a stable inode ref, even
when we aren't holding i_lock.  This avoids adding new and unnecessary
locking dependencies.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/ioctl.c b/fs/ceph/ioctl.c
index 8888c9ba..ef0b5f4 100644
--- a/fs/ceph/ioctl.c
+++ b/fs/ceph/ioctl.c
@@ -73,7 +73,8 @@
 				       USE_AUTH_MDS);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 	req->r_inode_drop = CEPH_CAP_FILE_SHARED | CEPH_CAP_FILE_EXCL;
 
 	req->r_args.setlayout.layout.fl_stripe_unit =
@@ -135,7 +136,8 @@
 
 	if (IS_ERR(req))
 		return PTR_ERR(req);
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 
 	req->r_args.setlayout.layout.fl_stripe_unit =
 			cpu_to_le32(l.stripe_unit);