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/inode.c b/fs/ceph/inode.c
index 70b6a48..d8858e9 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -1101,10 +1101,10 @@
 				goto done;
 			}
 			req->r_dentry = dn;  /* may have spliced */
-			igrab(in);
+			ihold(in);
 		} else if (ceph_ino(in) == vino.ino &&
 			   ceph_snap(in) == vino.snap) {
-			igrab(in);
+			ihold(in);
 		} else {
 			dout(" %p links to %p %llx.%llx, not %llx.%llx\n",
 			     dn, in, ceph_ino(in), ceph_snap(in),
@@ -1144,7 +1144,7 @@
 			goto done;
 		}
 		req->r_dentry = dn;  /* may have spliced */
-		igrab(in);
+		ihold(in);
 		rinfo->head->is_dentry = 1;  /* fool notrace handlers */
 	}
 
@@ -1328,7 +1328,7 @@
 	if (queue_work(ceph_inode_to_client(inode)->wb_wq,
 		       &ceph_inode(inode)->i_wb_work)) {
 		dout("ceph_queue_writeback %p\n", inode);
-		igrab(inode);
+		ihold(inode);
 	} else {
 		dout("ceph_queue_writeback %p failed\n", inode);
 	}
@@ -1353,7 +1353,7 @@
 	if (queue_work(ceph_inode_to_client(inode)->pg_inv_wq,
 		       &ceph_inode(inode)->i_pg_inv_work)) {
 		dout("ceph_queue_invalidate %p\n", inode);
-		igrab(inode);
+		ihold(inode);
 	} else {
 		dout("ceph_queue_invalidate %p failed\n", inode);
 	}
@@ -1477,7 +1477,7 @@
 	if (queue_work(ceph_sb_to_client(inode->i_sb)->trunc_wq,
 		       &ci->i_vmtruncate_work)) {
 		dout("ceph_queue_vmtruncate %p\n", inode);
-		igrab(inode);
+		ihold(inode);
 	} else {
 		dout("ceph_queue_vmtruncate %p failed, pending=%d\n",
 		     inode, ci->i_truncate_pending);
@@ -1738,7 +1738,8 @@
 		__mark_inode_dirty(inode, inode_dirty_flags);
 
 	if (mask) {
-		req->r_inode = igrab(inode);
+		req->r_inode = inode;
+		ihold(inode);
 		req->r_inode_drop = release;
 		req->r_args.setattr.mask = cpu_to_le32(mask);
 		req->r_num_caps = 1;
@@ -1779,7 +1780,8 @@
 	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, USE_ANY_MDS);
 	if (IS_ERR(req))
 		return PTR_ERR(req);
-	req->r_inode = igrab(inode);
+	req->r_inode = inode;
+	ihold(inode);
 	req->r_num_caps = 1;
 	req->r_args.getattr.mask = cpu_to_le32(mask);
 	err = ceph_mdsc_do_request(mdsc, NULL, req);