linux-ext4 - Re: [PATCH] ext4: don't update s_rev

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Date:   Thu, 14 Feb 2019 21:10:29 -0500
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     Andreas Dilger <adilger@...ger.ca>
CC:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH] ext4: don't update s_rev_level if not required

On Sat, Jan 12, 2019 at 05:36:40PM -0700, Andreas Dilger wrote:
> Don't update the superblock s_rev_level during mount if it isn't
> actually necessary, only if superblock features are being set by
> the kernel.  This was originally added for ext3 since it always
> set the INCOMPAT_RECOVER and HAS_JOURNAL features during mount,
> but this is not needed since no journal mode was added to ext4.
> 
> That will allow Geert to mount his 20-year-old ext2 rev 0.0 m68k
> filesystem, as a testament of the backward compatibility of ext4.
> 
> Fixes: 0390131ba84f ("ext4: Allow ext4 to run without a journal")
> Signed-off-by: Andreas Dilger <adilger@...ger.ca>

Thanks, applied.  I had to move the declaration of
ext4_update_dynamic_rev() earlier as Geert suggested.

						- Ted