From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: [PATCH 6/18] sanitize the interface of graft_tree(). Date: Tue, 08 Nov 2005 02:01:31 +0000 Message-ID: Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linuxram@us.ibm.com Return-path: Received: from zeniv.linux.org.uk ([195.92.253.2]:23245 "EHLO ZenIV.linux.org.uk") by vger.kernel.org with ESMTP id S965173AbVKHCBg (ORCPT ); Mon, 7 Nov 2005 21:01:36 -0500 To: torvalds@osdl.org Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org From: Ram Pai Date: 1131401789 -0500 Old semanitcs: graft_tree() grabs a reference on the vfsmount before returning success. New one: graft_tree() leaves that to caller. All the callers of graft_tree() immediately dropped that reference anyway. Changing the interface takes care of this unnecessary overhead. Idea proposed by Al-Viro. Signed-off-by: Ram Pai (linuxram@us.ibm.com) Signed-off-by: Al Viro --- fs/namespace.c | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-) e43480493368cfdc525357e242bcd01a3bfdc5db diff --git a/fs/namespace.c b/fs/namespace.c --- a/fs/namespace.c +++ b/fs/namespace.c @@ -650,7 +650,6 @@ static int graft_tree(struct vfsmount *m attach_mnt(mnt, nd); list_add_tail(&head, &mnt->mnt_list); list_splice(&head, current->namespace->list.prev); - mntget(mnt); err = 0; touch_namespace(current->namespace); } @@ -702,8 +701,7 @@ static int do_loopback(struct nameidata spin_lock(&vfsmount_lock); umount_tree(mnt); spin_unlock(&vfsmount_lock); - } else - mntput(mnt); + } out: up_write(¤t->namespace->sem); @@ -857,15 +855,17 @@ int do_add_mount(struct vfsmount *newmnt goto unlock; newmnt->mnt_flags = mnt_flags; - newmnt->mnt_namespace = current->namespace; - err = graft_tree(newmnt, nd); + if ((err = graft_tree(newmnt, nd))) + goto unlock; - if (err == 0 && fslist) { + if (fslist) { /* add to the specified expiration list */ spin_lock(&vfsmount_lock); list_add_tail(&newmnt->mnt_expire, fslist); spin_unlock(&vfsmount_lock); } + up_write(¤t->namespace->sem); + return 0; unlock: up_write(¤t->namespace->sem);