Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763555AbYBHWiV (ORCPT ); Fri, 8 Feb 2008 17:38:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759413AbYBHW1b (ORCPT ); Fri, 8 Feb 2008 17:27:31 -0500 Received: from e2.ny.us.ibm.com ([32.97.182.142]:57298 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758760AbYBHW1V (ORCPT ); Fri, 8 Feb 2008 17:27:21 -0500 Subject: [RFC][PATCH 22/30] r/o bind mounts: elevate write count for chmod/chown callers To: linux-kernel@vger.kernel.org Cc: hch@lst.de, viro@ZenIV.linux.org.uk, viro@ftp.linux.org.uk, miklos@szeredi.hu, Dave Hansen From: Dave Hansen Date: Fri, 08 Feb 2008 14:27:17 -0800 References: <20080208222641.6024A7CC@kernel> In-Reply-To: <20080208222641.6024A7CC@kernel> Message-Id: <20080208222717.73677C5A@kernel> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3850 Lines: 137 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 Acked-by: Christoph Hellwig Signed-off-by: Andrew Morton --- linux-2.6.git-dave/fs/open.c | 39 ++++++++++++++++++++++++++++++--------- 1 file changed, 30 insertions(+), 9 deletions(-) diff -puN fs/open.c~r-o-bind-mounts-elevate-writer-count-for-chown-and-friends fs/open.c --- linux-2.6.git/fs/open.c~r-o-bind-mounts-elevate-writer-count-for-chown-and-friends 2008-02-08 13:04:57.000000000 -0800 +++ linux-2.6.git-dave/fs/open.c 2008-02-08 13:04:57.000000000 -0800 @@ -571,12 +571,12 @@ asmlinkage long sys_fchmod(unsigned int audit_inode(NULL, dentry); - 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; @@ -585,6 +585,8 @@ 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: @@ -604,13 +606,13 @@ 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) @@ -620,6 +622,8 @@ 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: @@ -642,9 +646,6 @@ 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; @@ -675,7 +676,12 @@ 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; @@ -695,7 +701,12 @@ 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; @@ -709,7 +720,12 @@ 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; @@ -726,9 +742,14 @@ 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); error = chown_common(dentry, user, group); + mnt_drop_write(file->f_vfsmnt); +out_fput: fput(file); out: return error; _ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/