From mboxrd@z Thu Jan 1 00:00:00 1970 From: Valerie Aurora Subject: [PATCH 32/39] union-mount: Implement union-aware writable open() Date: Mon, 3 May 2010 16:12:31 -0700 Message-ID: <1272928358-20854-33-git-send-email-vaurora@redhat.com> References: <1272928358-20854-1-git-send-email-vaurora@redhat.com> Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Christoph Hellwig , Jan Blunck , Valerie Aurora To: Alexander Viro Return-path: Received: from mx1.redhat.com ([209.132.183.28]:25849 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932342Ab0ECXOF (ORCPT ); Mon, 3 May 2010 19:14:05 -0400 In-Reply-To: <1272928358-20854-1-git-send-email-vaurora@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Copy up a file when opened with write permissions. Does not copy up the file data when O_TRUNC is specified. --- fs/namei.c | 28 ++++++++++++++++++++++++++++ 1 files changed, 28 insertions(+), 0 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index b00ece9..78c9b87 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1937,6 +1937,24 @@ exit: return ERR_PTR(error); } +static int open_union_copyup(struct nameidata *nd, struct path *path, + int open_flag) +{ + struct vfsmount *oldmnt = path->mnt; + int error; + + if (open_flag & O_TRUNC) + error = union_copyup_len(nd, path, 0); + else + error = union_copyup(nd, path); + if (error) + return error; + if (oldmnt != path->mnt) + mntput(nd->path.mnt); + + return error; +} + static struct file *do_last(struct nameidata *nd, struct path *path, int open_flag, int acc_mode, int mode, const char *pathname) @@ -1988,6 +2006,11 @@ static struct file *do_last(struct nameidata *nd, struct path *path, if (!path->dentry->d_inode->i_op->lookup) goto exit_dput; } + if (acc_mode & MAY_WRITE) { + error = open_union_copyup(nd, path, open_flag); + if (error) + goto exit_dput; + } path_to_nameidata(path, nd); audit_inode(pathname, nd->path.dentry); goto ok; @@ -2059,6 +2082,11 @@ static struct file *do_last(struct nameidata *nd, struct path *path, if (path->dentry->d_inode->i_op->follow_link) return NULL; + if (acc_mode & MAY_WRITE) { + error = open_union_copyup(nd, path, open_flag); + if (error) + goto exit_dput; + } path_to_nameidata(path, nd); error = -EISDIR; if (S_ISDIR(path->dentry->d_inode->i_mode)) -- 1.6.3.3