Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754674AbYAXTkp (ORCPT ); Thu, 24 Jan 2008 14:40:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756452AbYAXTew (ORCPT ); Thu, 24 Jan 2008 14:34:52 -0500 Received: from fxip-0047f.externet.hu ([88.209.222.127]:46530 "EHLO pomaz-ex.szeredi.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754494AbYAXTe3 (ORCPT ); Thu, 24 Jan 2008 14:34:29 -0500 Message-Id: <20080124193417.722190833@szeredi.hu> References: <20080124193341.166753833@szeredi.hu> User-Agent: quilt/0.45-1 Date: Thu, 24 Jan 2008 20:33:43 +0100 From: Miklos Szeredi To: akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [patch 02/26] mount options: add generic_show_options() Content-Disposition: inline; filename=generic_show_options.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3933 Lines: 128 From: Miklos Szeredi Add a new s_options field to struct super_block. Filesystems can save mount options passed to them in mount or remount. It is automatically freed when the superblock is destroyed. A new helper function, generic_show_options() is introduced, which uses this field to display the mount options in /proc/mounts. Another helper function, save_mount_options() may be used by filesystems to save the options in the super block. Signed-off-by: Miklos Szeredi --- Index: linux/fs/namespace.c =================================================================== --- linux.orig/fs/namespace.c 2008-01-24 17:07:46.000000000 +0100 +++ linux/fs/namespace.c 2008-01-24 17:34:50.000000000 +0100 @@ -575,6 +575,50 @@ void mnt_unpin(struct vfsmount *mnt) EXPORT_SYMBOL(mnt_unpin); +static inline void mangle(struct seq_file *m, const char *s) +{ + seq_escape(m, s, " \t\n\\"); +} + +/* + * Simple .show_options callback for filesystems which don't want to + * implement more complex mount option showing. + * + * See also save_mount_options(). + */ +int generic_show_options(struct seq_file *m, struct vfsmount *mnt) +{ + const char *options = mnt->mnt_sb->s_options; + + if (options != NULL && options[0]) { + seq_putc(m, ','); + mangle(m, options); + } + + return 0; +} +EXPORT_SYMBOL(generic_show_options); + +/* + * If filesystem uses generic_show_options(), this function should be + * called from the fill_super() callback. + * + * The .remount_fs callback usually needs to be handled in a special + * way, to make sure, that previous options are not overwritten if the + * remount fails. + * + * Also note, that if the filesystem's .remount_fs function doesn't + * reset all options to their default value, but changes only newly + * given options, then the displayed options will not reflect reality + * any more. + */ +void save_mount_options(struct super_block *sb, char *options) +{ + kfree(sb->s_options); + sb->s_options = kstrdup(options, GFP_KERNEL); +} +EXPORT_SYMBOL(save_mount_options); + /* iterator */ static void *m_start(struct seq_file *m, loff_t *pos) { @@ -596,11 +640,6 @@ static void m_stop(struct seq_file *m, v up_read(&namespace_sem); } -static inline void mangle(struct seq_file *m, const char *s) -{ - seq_escape(m, s, " \t\n\\"); -} - static int show_vfsmnt(struct seq_file *m, void *v) { struct vfsmount *mnt = list_entry(v, struct vfsmount, mnt_list); Index: linux/fs/super.c =================================================================== --- linux.orig/fs/super.c 2008-01-24 17:07:46.000000000 +0100 +++ linux/fs/super.c 2008-01-24 17:12:33.000000000 +0100 @@ -105,6 +105,7 @@ static inline void destroy_super(struct { security_sb_free(s); kfree(s->s_subtype); + kfree(s->s_options); kfree(s); } Index: linux/include/linux/fs.h =================================================================== --- linux.orig/include/linux/fs.h 2008-01-24 17:07:46.000000000 +0100 +++ linux/include/linux/fs.h 2008-01-24 17:12:33.000000000 +0100 @@ -1042,6 +1042,12 @@ struct super_block { * in /proc/mounts will be "type.subtype" */ char *s_subtype; + + /* + * Saved mount options for lazy filesystems using + * generic_show_options() + */ + char *s_options; }; extern struct timespec current_fs_time(struct super_block *sb); @@ -1992,6 +1998,9 @@ extern int __must_check inode_setattr(st extern void file_update_time(struct file *file); +extern int generic_show_options(struct seq_file *m, struct vfsmount *mnt); +extern void save_mount_options(struct super_block *sb, char *options); + static inline ino_t parent_ino(struct dentry *dentry) { ino_t res; -- -- 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/