From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: [PATCH 08/26] elevate writer count for chown and friends Date: Fri, 22 Jun 2007 13:03:13 -0700 Message-ID: <20070622200313.D7CF53B8@kernel> References: <20070622200303.82D9CC3A@kernel> Cc: linux-fsdevel@vger.kernel.org, hch@infradead.org, viro@ftp.linux.org.uk, Dave Hansen To: akpm@osdl.org Return-path: Received: from e33.co.us.ibm.com ([32.97.110.151]:47854 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751144AbXFVUDU (ORCPT ); Fri, 22 Jun 2007 16:03:20 -0400 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e33.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id l5MK3IOS017550 for ; Fri, 22 Jun 2007 16:03:18 -0400 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v8.3) with ESMTP id l5MK3Hbj209224 for ; Fri, 22 Jun 2007 14:03:17 -0600 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l5MK3FtC012139 for ; Fri, 22 Jun 2007 14:03:17 -0600 In-Reply-To: <20070622200303.82D9CC3A@kernel> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org chown/chmod,etc... don't call permission in the same way that the normal "open for write" calls do. They still write to the filesystem, so bump the write count during these operations. Signed-off-by: Dave Hansen --- lxc-dave/fs/open.c | 39 ++++++++++++++++++++++++++++++--------- 1 file changed, 30 insertions(+), 9 deletions(-) diff -puN fs/open.c~06-24-elevate-writer-count-for-chown-and-friends fs/open.c --- lxc/fs/open.c~06-24-elevate-writer-count-for-chown-and-friends 2007-06-21 23:23:16.000000000 -0700 +++ lxc-dave/fs/open.c 2007-06-21 23:23:16.000000000 -0700 @@ -508,12 +508,12 @@ asmlinkage long sys_fchmod(unsigned int audit_inode(NULL, inode); - err = -EROFS; - if (IS_RDONLY(inode)) + err = mnt_want_write(file->f_vfsmnt); + if (err) goto out_putf; err = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) - goto out_putf; + goto out_drop_write; mutex_lock(&inode->i_mutex); if (mode == (mode_t) -1) mode = inode->i_mode; @@ -522,6 +522,8 @@ asmlinkage long sys_fchmod(unsigned int err = notify_change(dentry, &newattrs); mutex_unlock(&inode->i_mutex); +out_drop_write: + mnt_drop_write(file->f_vfsmnt); out_putf: fput(file); out: @@ -541,13 +543,13 @@ asmlinkage long sys_fchmodat(int dfd, co goto out; inode = nd.dentry->d_inode; - error = -EROFS; - if (IS_RDONLY(inode)) + error = mnt_want_write(nd.mnt); + if (error) goto dput_and_out; error = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) - goto dput_and_out; + goto out_drop_write; mutex_lock(&inode->i_mutex); if (mode == (mode_t) -1) @@ -557,6 +559,8 @@ asmlinkage long sys_fchmodat(int dfd, co error = notify_change(nd.dentry, &newattrs); mutex_unlock(&inode->i_mutex); +out_drop_write: + mnt_drop_write(nd.mnt); dput_and_out: path_release(&nd); out: @@ -579,9 +583,6 @@ static int chown_common(struct dentry * printk(KERN_ERR "chown_common: NULL inode\n"); goto out; } - error = -EROFS; - if (IS_RDONLY(inode)) - goto out; error = -EPERM; if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) goto out; @@ -611,7 +612,12 @@ asmlinkage long sys_chown(const char __u error = user_path_walk(filename, &nd); if (error) goto out; + error = mnt_want_write(nd.mnt); + if (error) + goto out_release; error = chown_common(nd.dentry, user, group); + mnt_drop_write(nd.mnt); +out_release: path_release(&nd); out: return error; @@ -631,7 +637,12 @@ asmlinkage long sys_fchownat(int dfd, co error = __user_walk_fd(dfd, filename, follow, &nd); if (error) goto out; + error = mnt_want_write(nd.mnt); + if (error) + goto out_release; error = chown_common(nd.dentry, user, group); + mnt_drop_write(nd.mnt); +out_release: path_release(&nd); out: return error; @@ -645,7 +656,12 @@ asmlinkage long sys_lchown(const char __ error = user_path_walk_link(filename, &nd); if (error) goto out; + error = mnt_want_write(nd.mnt); + if (error) + goto out_release; error = chown_common(nd.dentry, user, group); + mnt_drop_write(nd.mnt); +out_release: path_release(&nd); out: return error; @@ -662,9 +678,14 @@ asmlinkage long sys_fchown(unsigned int if (!file) goto out; + error = mnt_want_write(file->f_vfsmnt); + if (error) + goto out_fput; dentry = file->f_path.dentry; audit_inode(NULL, dentry->d_inode); error = chown_common(dentry, user, group); + mnt_drop_write(file->f_vfsmnt); +out_fput: fput(file); out: return error; _