From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [RFC] Removing b_end_io
Date: Sun, 25 Oct 2020 11:56:52 -0400 [thread overview]
Message-ID: <20201025155652.GB5691@mit.edu> (raw)
In-Reply-To: <20201025044438.GI20115@casper.infradead.org>
On Sun, Oct 25, 2020 at 04:44:38AM +0000, Matthew Wilcox wrote:
> @@ -3068,6 +3069,12 @@ static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
> }
>
> submit_bio(bio);
> +}
> +
> +static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,
> + enum rw_hint write_hint, struct writeback_control *wbc)
> +{
> + __bh_submit(bh, op | op_flags, write_hint, wbc, end_bio_bh_io_sync);
> return 0;
> }
>
I believe this will break use cases where the file system sets
bh->b_end_io and then calls submit_bh(), which then calls
submit_bh_wbc(). That's because with this change, calls to
submit_bh_wbc() --- include submit_bh() --- ignores bh->b_end_io and
results in end_bio_bh_io_sync getting used.
Filesystems that do this includes fs/ntfs, fs/resiserfs.
In this case, that can probably be fixed by changing submit_bh() to
pass in bh->b_end_io, or switching those users to use the new
bh_submit() function to prevent these breakages.
- Ted
next prev parent reply other threads:[~2020-10-25 15:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-25 4:44 [RFC] Removing b_end_io Matthew Wilcox
2020-10-25 15:56 ` Theodore Y. Ts'o [this message]
2020-10-25 18:58 ` Matthew Wilcox
2020-10-27 18:25 ` Christoph Hellwig
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