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Date:	Tue, 24 Jul 2007 22:15:22 +0200
From:	Miklos Szeredi <miklos@...redi.hu>
To:	linux-ext4@...r.kernel.org
CC:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] ext2: show all mount options

From: Miklos Szeredi <mszeredi@...e.cz>

Using mtab is problematic for various reasons, one of them is that
unprivileged mounts won't turn up in there.  So we want to get rid of
it, and use /proc/mounts instead.

But most filesystems are lazy, and are not showing all mount options.
Which means, that without mtab, the user won't be able to see some or
all of the options.

It would be nice if the generic code could remember the mount options,
and show them without the need to add extra code to filesystems.  But
this is not easy, because different filesystems handle mount options
differently.  For example on remount, ext* will overwrite only the
given options, and not tough the rest.  This is not taken into account
by mount(8) either, so /etc/mtab will be broken in this case.

This series fixes up ->show_options() in ext[234].

Signed-off-by: Miklos Szeredi <mszeredi@...e.cz>
---

Index: linux-2.6/fs/ext2/super.c
===================================================================
--- linux-2.6.orig/fs/ext2/super.c	2007-07-23 17:41:29.000000000 +0200
+++ linux-2.6/fs/ext2/super.c	2007-07-23 18:02:38.000000000 +0200
@@ -203,10 +203,66 @@ static void ext2_clear_inode(struct inod
 
 static int ext2_show_options(struct seq_file *seq, struct vfsmount *vfs)
 {
-	struct ext2_sb_info *sbi = EXT2_SB(vfs->mnt_sb);
+	struct super_block *sb = vfs->mnt_sb;
+	struct ext2_sb_info *sbi = EXT2_SB(sb);
+	struct ext2_super_block *es = sbi->s_es;
+	unsigned long def_mount_opts;
+
+	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
 
-	if (sbi->s_mount_opt & EXT2_MOUNT_GRPID)
+	if (sbi->s_sb_block != 1)
+		seq_printf(seq, ",sb=%lu", sbi->s_sb_block);
+	if (test_opt(sb, MINIX_DF))
+		seq_puts(seq, ",minixdf");
+	if (test_opt(sb, GRPID))
 		seq_puts(seq, ",grpid");
+	if (!test_opt(sb, GRPID) && (def_mount_opts & EXT2_DEFM_BSDGROUPS))
+		seq_puts(seq, ",nogrpid");
+	if (sbi->s_resuid != EXT2_DEF_RESUID ||
+	    le16_to_cpu(es->s_def_resuid) != EXT2_DEF_RESUID) {
+		seq_printf(seq, ",resuid=%u", sbi->s_resuid);
+	}
+	if (sbi->s_resgid != EXT2_DEF_RESGID ||
+	    le16_to_cpu(es->s_def_resgid) != EXT2_DEF_RESGID) {
+		seq_printf(seq, ",resgid=%u", sbi->s_resgid);
+	}
+	if (test_opt(sb, ERRORS_CONT)) {
+		int def_errors = le16_to_cpu(es->s_errors);
+
+		if (def_errors == EXT2_ERRORS_PANIC ||
+		    def_errors == EXT2_ERRORS_RO) {
+			seq_puts(seq, ",errors=continue");
+		}
+	}
+	if (test_opt(sb, ERRORS_RO))
+		seq_puts(seq, ",errors=remount-ro");
+	if (test_opt(sb, ERRORS_PANIC))
+		seq_puts(seq, ",errors=panic");
+	if (test_opt(sb, NO_UID32))
+		seq_puts(seq, ",nouid32");
+	if (test_opt(sb, DEBUG))
+		seq_puts(seq, ",debug");
+	if (test_opt(sb, OLDALLOC))
+		seq_puts(seq, ",oldalloc");
+
+#ifdef CONFIG_EXT2_FS_XATTR
+	if (test_opt(sb, XATTR_USER))
+		seq_puts(seq, ",user_xattr");
+	if (!test_opt(sb, XATTR_USER) &&
+	    (def_mount_opts & EXT2_DEFM_XATTR_USER)) {
+		seq_puts(seq, ",nouser_xattr");
+	}
+#endif
+
+#ifdef CONFIG_EXT2_FS_POSIX_ACL
+	if (test_opt(sb, POSIX_ACL))
+		seq_puts(seq, ",acl");
+	if (!test_opt(sb, POSIX_ACL) && (def_mount_opts & EXT2_DEFM_ACL))
+		seq_puts(seq, ",noacl");
+#endif
+
+	if (test_opt(sb, NOBH))
+		seq_puts(seq, ",nobh");
 
 #if defined(CONFIG_QUOTA)
 	if (sbi->s_mount_opt & EXT2_MOUNT_USRQUOTA)
@@ -658,6 +714,7 @@ static int ext2_fill_super(struct super_
 	if (!sbi)
 		return -ENOMEM;
 	sb->s_fs_info = sbi;
+	sbi->s_sb_block = sb_block;
 
 	/*
 	 * See what the current blocksize for the device is, and
Index: linux-2.6/include/linux/ext2_fs_sb.h
===================================================================
--- linux-2.6.orig/include/linux/ext2_fs_sb.h	2007-07-23 17:41:29.000000000 +0200
+++ linux-2.6/include/linux/ext2_fs_sb.h	2007-07-23 18:01:40.000000000 +0200
@@ -39,6 +39,7 @@ struct ext2_sb_info {
 	struct ext2_super_block * s_es;	/* Pointer to the super block in the buffer */
 	struct buffer_head ** s_group_desc;
 	unsigned long  s_mount_opt;
+	unsigned long s_sb_block;
 	uid_t s_resuid;
 	gid_t s_resgid;
 	unsigned short s_mount_state;
-
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