linux-ext4 - Re: [PATCH v3 2/5] ext4: remove ext4_buffer

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Message-ID: <20200807175307.GW7657@mit.edu>
Date:   Fri, 7 Aug 2020 13:53:07 -0400
From:   tytso@....edu
To:     "zhangyi (F)" <yi.zhang@...wei.com>
Cc:     <linux-ext4@...r.kernel.org>, <jack@...e.cz>,
        <adilger.kernel@...ger.ca>, <zhangxiaoxu5@...wei.com>,
        <linux-fsdevel@...r.kernel.org>
Subject: Re: [PATCH v3 2/5] ext4: remove ext4_buffer_uptodate()

On Sat, Jun 20, 2020 at 10:54:24AM +0800, zhangyi (F) wrote:
> After we add async write error check in ext4_journal_get_write_access(),
> we can remove the partial fix for filesystem inconsistency problem
> caused by reading old data from disk, which in commit <7963e5ac9012>
> "ext4: treat buffers with write errors as containing valid data" and
> <cf2834a5ed57> "ext4: treat buffers contining write errors as valid in
> ext4_sb_bread()".
> 
> Signed-off-by: zhangyi (F) <yi.zhang@...wei.com>

I think it's better to keep these checks (in commits 2 and 3) because
ext4_error() doens't guarantee that the file system will be aborted.
For better or for worse, there are a large number of file systems
which default to errors=continue.

So if we notice that the buffer is not up to date, due to a write
error, we can avoid some (although not all) damage if we keep this
workaround.

					- Ted