On Wed, 2007-07-11 at 00:38 -0500, Jose R. Santos wrote:
> On Tue, 10 Jul 2007 16:30:25 -0700
> Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> > On Sun, 01 Jul 2007 03:36:48 -0400
> > Mingming Cao <cmm@xxxxxxxxxx> wrote:
> >
> > > > On Jun 07, 2007 23:45 -0500, Jose R. Santos wrote:
> > > > > The jbd2-debug file used to be located in /proc/sys/fs/jbd2-debug, but
> > > > > create_proc_entry() does not do lookups on file names with more that one
> > > > > directory deep. This causes the entry creation to fail and hence, no proc
> > > > > file is created. This patch moves the file to /proc/jbd2-degug.
> > > > >
> > > > > The file could be move to /proc/fs/jbd2/jbd2-debug, but it would require
> > > > > some minor alterations to the jbd-stats patch.
> > > >
> > > > I don't think we really want to be adding top-level files in /proc.
> > > > What about using the "debugfs" filesystem (not to be confused with
> > > > the e2fsprogs 'debugfs' command)?
> > >
> > > How about this then? Moved the file to use debugfs as well as having
> > > the nice effect of removing more lines than what it adds.
> > >
> > > Signed-off-by: Jose R. Santos <jrs@xxxxxxxxxx>
> >
> > Please clean up the changelog.
> >
> > The changelog should include information about the location and the content
> > of these debugfs files. it should provide any instructions which users
> > will need to be able to create and use those files.
>
> Will fix.
>
> > Alternatively (and preferably) do this via an update to
> > Documentation/filesystems/ext4.txt.
>
> Seems like I also need to update the doc on Kconfig as well. Do you
> prefer this in separate patches? (current patch, kconfig patch, ext4
> doc update patch?
>
> > > fs/jbd2/journal.c | 62 20 + 42 - 0 !
> > > include/linux/jbd2.h | 2 1 + 1 - 0 !
> > > 2 files changed, 21 insertions(+), 43 deletions(-)
> >
> > Again, this patch isn't in Ted's kernel.org directory and hasn't been in -mm.
> >
> > Apart from the lack of testing and review which this causes, it means I
> > can't just do `pushpatch name-of-this-patch' and look at it in tkdiff. So
> > I squint at the diff, but that's harder when the diff wasn't prepared with
> > `diff -p'. Oh well.
>
> Will fix.
>
> >
> > > Index: linux-2.6.22-rc4/fs/jbd2/journal.c
> > > ===================================================================
> > > --- linux-2.6.22-rc4.orig/fs/jbd2/journal.c 2007-06-11 16:16:18.000000000 -0700
> > > +++ linux-2.6.22-rc4/fs/jbd2/journal.c 2007-06-11 16:36:10.000000000 -0700
> > > @@ -35,6 +35,7 @@
> > > #include <linux/kthread.h>
> > > #include <linux/poison.h>
> > > #include <linux/proc_fs.h>
> > > +#include <linux/debugfs.h>
> > >
> > > #include <asm/uaccess.h>
> > > #include <asm/page.h>
> > > @@ -1954,60 +1955,37 @@
> > > * /proc tunables
> > > */
> > > #if defined(CONFIG_JBD2_DEBUG)
> > > -int jbd2_journal_enable_debug;
> > > +u16 jbd2_journal_enable_debug;
> > > EXPORT_SYMBOL(jbd2_journal_enable_debug);
> > > #endif
> > >
> > > -#if defined(CONFIG_JBD2_DEBUG) && defined(CONFIG_PROC_FS)
> > > +#if defined(CONFIG_JBD2_DEBUG) && defined(CONFIG_DEBUG_FS)
> >
> > Has this been compile-tested with CONFIG_DEBUGFS=n?
>
> I think I did, but honestly don't remember. Will check with the new
> patch. :)
>
Yes, I remember I did, that discovered some inconsistency in ext4 code,
which has already been fixed.
> > >
> > > -#define create_jbd_proc_entry() do {} while (0)
> > > -#define jbd2_remove_jbd_proc_entry() do {} while (0)
> > > +#define jbd2_create_debugfs_entry() do {} while (0)
> > > +#define jbd2_remove_debugfs_entry() do {} while (0)
> >
> > I suggest that these be converted to (preferable) inline functions while
> > you're there.
>
> OK.
>
> > > #endif
> > >
> > > @@ -2067,7 +2045,7 @@
> > > ret = journal_init_caches();
> > > if (ret != 0)
> > > jbd2_journal_destroy_caches();
> > > - create_jbd_proc_entry();
> > > + jbd2_create_debugfs_entry();
> > > return ret;
> > > }
> > >
> > > @@ -2078,7 +2056,7 @@
> > > if (n)
> > > printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n);
> > > #endif
> > > - jbd2_remove_jbd_proc_entry();
> > > + jbd2_remove_debugfs_entry();
> > > jbd2_journal_destroy_caches();
> > > }
> > >
> > > Index: linux-2.6.22-rc4/include/linux/jbd2.h
> > > ===================================================================
> > > --- linux-2.6.22-rc4.orig/include/linux/jbd2.h 2007-06-11 16:16:18.000000000 -0700
> > > +++ linux-2.6.22-rc4/include/linux/jbd2.h 2007-06-11 16:35:25.000000000 -0700
> > > @@ -57,7 +57,7 @@
> > > * CONFIG_JBD2_DEBUG is on.
> > > */
> > > #define JBD_EXPENSIVE_CHECKING
> >
> > JBD2?
> >
> > > -extern int jbd2_journal_enable_debug;
> > > +extern u16 jbd2_journal_enable_debug;
> >
> > Why was this made 16-bit? To save 2 bytes? Could have saved 3 if we're
> > going to do that.
>
> OK.
>
> > Shoudln't all this debug info be a per-superblock thing rather than
> > kernel-wide?
>
> I don't think it is worth pursuing this feature since this seems to
> have been broken for a while now (its been there since the first git
> revission in ext3) and nobody has noticed it until now. It could be
> address on a later patch though, since the initial purpose of the patch
> was to fix the broken JBD2_DEBUG option. Of course, this may not be
> clearly express in the changelog. :)
>
> -JRS
-
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
