Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946131AbXBIWyF (ORCPT ); Fri, 9 Feb 2007 17:54:05 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946143AbXBIWyC (ORCPT ); Fri, 9 Feb 2007 17:54:02 -0500 Received: from e2.ny.us.ibm.com ([32.97.182.142]:52036 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423377AbXBIWxs (ORCPT ); Fri, 9 Feb 2007 17:53:48 -0500 Subject: [PATCH 21/22] honor r/w changes at do_remount() time To: linux-kernel@vger.kernel.org Cc: akpm@osdl.org, hch@infradead.org, Dave Hansen From: Dave Hansen Date: Fri, 09 Feb 2007 14:53:44 -0800 References: <20070209225329.27619A62@localhost.localdomain> In-Reply-To: <20070209225329.27619A62@localhost.localdomain> Message-Id: <20070209225344.93A75D35@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2837 Lines: 84 Originally from: Herbert Poetzl This is the core of the read-only bind mount patch set. Note that this does _not_ add a "ro" option directly to the bind mount operation. If you require such a mount, you must first do the bind, then follow it up with a 'mount -o remount,ro' operation. Signed-off-by: Dave Hansen --- lxc-dave/fs/namespace.c | 24 ++++++++++++++++++++++-- lxc-dave/fs/open.c | 2 +- 2 files changed, 23 insertions(+), 3 deletions(-) diff -puN fs/namespace.c~23-24-honor-r-w-changes-at-do-remount-time fs/namespace.c --- lxc/fs/namespace.c~23-24-honor-r-w-changes-at-do-remount-time 2007-02-09 14:27:00.000000000 -0800 +++ lxc-dave/fs/namespace.c 2007-02-09 14:27:00.000000000 -0800 @@ -443,7 +443,7 @@ static int show_vfsmnt(struct seq_file * seq_path(m, mnt, mnt->mnt_root, " \t\n\\"); seq_putc(m, ' '); mangle(m, mnt->mnt_sb->s_type->name); - seq_puts(m, mnt->mnt_sb->s_flags & MS_RDONLY ? " ro" : " rw"); + seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw"); for (fs_infop = fs_info; fs_infop->flag; fs_infop++) { if (mnt->mnt_sb->s_flags & fs_infop->flag) seq_puts(m, fs_infop->str); @@ -1017,6 +1017,23 @@ out: return err; } +static int change_mount_flags(struct vfsmount *mnt, int ms_flags) +{ + int error = 0; + int readonly_request = 0; + + if (ms_flags & MS_RDONLY) + readonly_request = 1; + if (readonly_request == __mnt_is_readonly(mnt)) + return 0; + + if (readonly_request) + error = mnt_make_readonly(mnt); + else + __mnt_unmake_readonly(mnt); + return error; +} + /* * change filesystem flags. dir should be a physical root of filesystem. * If you've mounted a non-root directory somewhere and want to do remount @@ -1038,7 +1055,10 @@ static int do_remount(struct nameidata * return -EINVAL; down_write(&sb->s_umount); - err = do_remount_sb(sb, flags, data, 0); + if (flags & MS_BIND) + err = change_mount_flags(nd->mnt, flags); + else + err = do_remount_sb(sb, flags, data, 0); if (!err) nd->mnt->mnt_flags = mnt_flags; up_write(&sb->s_umount); diff -puN fs/open.c~23-24-honor-r-w-changes-at-do-remount-time fs/open.c --- lxc/fs/open.c~23-24-honor-r-w-changes-at-do-remount-time 2007-02-09 14:27:00.000000000 -0800 +++ lxc-dave/fs/open.c 2007-02-09 14:27:00.000000000 -0800 @@ -401,7 +401,7 @@ asmlinkage long sys_faccessat(int dfd, c special_file(nd.dentry->d_inode->i_mode)) goto out_path_release; - if(IS_RDONLY(nd.dentry->d_inode)) + if(__mnt_is_readonly(nd.mnt) || IS_RDONLY(nd.dentry->d_inode)) res = -EROFS; out_path_release: _ - 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/