[PATCH] properly show journal checksum/async options

[PATCH] properly show journal checksum/async options

[Eric Sandeen]

The journal_checksum option is not being displayed in
/proc/mounts ... add this to the show_options() output, but
only if journal_async_commit is not specified, as that enables
journal_checksum internally.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

(Aside: this reminds me that we only show non-default options
in show_options; has there been any discussion of whether
these should be defaults?)

Index: linux-2.6/fs/ext4/super.c
===================================================================
--- linux-2.6.orig/fs/ext4/super.c	2008-09-14 16:12:54.898077064 -0500
+++ linux-2.6/fs/ext4/super.c	2008-09-14 16:13:22.878077407 -0500
@@ -746,8 +746,12 @@ static int ext4_show_options(struct seq_
 	 */
 	seq_puts(seq, ",barrier=");
 	seq_puts(seq, test_opt(sb, BARRIER) ? "1" : "0");
+	/* journal_async_commit enables journal_checksum internally */
 	if (test_opt(sb, JOURNAL_ASYNC_COMMIT))
 		seq_puts(seq, ",journal_async_commit");
+	else if (test_opt(sb, JOURNAL_CHECKSUM))
+		seq_puts(seq, ",journal_checksum");
+
 	if (test_opt(sb, NOBH))
 		seq_puts(seq, ",nobh");
 	if (!test_opt(sb, EXTENTS))

Re: [PATCH] properly show journal checksum/async options

[Theodore Tso]

On Sun, Sep 14, 2008 at 02:18:59PM -0700, Eric Sandeen wrote:
> The journal_checksum option is not being displayed in
> /proc/mounts ... add this to the show_options() output, but
> only if journal_async_commit is not specified, as that enables
> journal_checksum internally.
> 
> Signed-off-by: Eric Sandeen <sandeen@redhat.com>

Acked-by: "Theodore Ts'o" <tytso@mit.edu>

I'll add it to the patch queue, probably combined with a patch to add
journal_sync_commit, and with a patch to make journal_async_commit the
default.

> (Aside: this reminds me that we only show non-default options
> in show_options; has there been any discussion of whether
> these should be defaults?)

Good point, thanks for raising the question.

The reason why journal_async_commit wasn't turned on by default
originally was because e2fsck didn't have support for journal
checksums before e2fsprogs 1.41.0.  At this point, it seems like
turning on async_commit is the obvious (and performant) thing to do;
any objections?

	    				- Ted