From mboxrd@z Thu Jan 1 00:00:00 1970 From: Valerie Aurora Subject: [PATCH 69/74] union-mount: Implement union-aware truncate() Date: Tue, 22 Mar 2011 19:05:00 -0700 Message-ID: <1300845905-14433-26-git-send-email-valerie.aurora@gmail.com> References: <1300845905-14433-1-git-send-email-valerie.aurora@gmail.com> Cc: viro@zeniv.linux.org.uk, Valerie Aurora , Valerie Aurora To: linux-fsdevel@vger.kernel.org, linux@vger.kernel.org Return-path: Received: from mail-yx0-f174.google.com ([209.85.213.174]:35146 "EHLO mail-yx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755289Ab1CWCGW (ORCPT ); Tue, 22 Mar 2011 22:06:22 -0400 In-Reply-To: <1300845905-14433-1-git-send-email-valerie.aurora@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: From: Valerie Aurora Signed-off-by: Valerie Aurora --- fs/open.c | 24 ++++++++++++++++++++---- 1 files changed, 20 insertions(+), 4 deletions(-) diff --git a/fs/open.c b/fs/open.c index 2b12488..23f4b75 100644 --- a/fs/open.c +++ b/fs/open.c @@ -65,14 +65,17 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs, static long do_sys_truncate(const char __user *pathname, loff_t length) { struct path path; + struct nameidata nd; + struct vfsmount *mnt; struct inode *inode; + char *tmp; int error; error = -EINVAL; if (length < 0) /* sorry, but loff_t says... */ goto out; - error = user_path(pathname, &path); + error = user_path_nd(AT_FDCWD, pathname, 0, &nd, &path, &tmp); if (error) goto out; inode = path.dentry->d_inode; @@ -86,11 +89,16 @@ static long do_sys_truncate(const char __user *pathname, loff_t length) if (!S_ISREG(inode->i_mode)) goto dput_and_out; - error = mnt_want_write(path.mnt); + if (IS_DIR_UNIONED(nd.path.dentry)) + mnt = nd.path.mnt; + else + mnt = path.mnt; + + error = mnt_want_write(mnt); if (error) goto dput_and_out; - error = inode_permission(inode, MAY_WRITE); + error = path_permission(&path, &nd.path, MAY_WRITE); if (error) goto mnt_drop_write_and_out; @@ -98,6 +106,12 @@ static long do_sys_truncate(const char __user *pathname, loff_t length) if (IS_APPEND(inode)) goto mnt_drop_write_and_out; + error = union_copyup_len(&nd, &path, length); + if (error) + goto mnt_drop_write_and_out; + + /* path may have changed after copyup */ + inode = path.dentry->d_inode; error = get_write_access(inode); if (error) goto mnt_drop_write_and_out; @@ -119,9 +133,11 @@ static long do_sys_truncate(const char __user *pathname, loff_t length) put_write_and_out: put_write_access(inode); mnt_drop_write_and_out: - mnt_drop_write(path.mnt); + mnt_drop_write(mnt); dput_and_out: path_put(&path); + path_put(&nd.path); + putname(tmp); out: return error; } -- 1.7.0.4