From: Jens Axboe <axboe@kernel.dk>
To: Yangtao Li <frank.li@vivo.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Lu Hongfei <luhongfei@vivo.com>,
linux-f2fs-devel@lists.sourceforge.net
Subject: [f2fs-dev] f2fs async buffered write patch
Date: Mon, 19 Jun 2023 14:43:56 -0600 [thread overview]
Message-ID: <1dc1a0f2-9be4-8ae0-da26-3c00c8a71b41@kernel.dk> (raw)
Hi,
I came across this patch in a news posting:
https://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs.git/commit/?h=dev&id=d618126911829523e35a61f4a5a4ad159b1b2c8d
which has me a bit worried. As far as I can tell, all that patch does is
set FMODE_BUF_WASYNC, and then just hope that the lower layers handle
the rest?
What happens if iocb->ki_flags & IOCB_NOWAIT is true, and now we do:
generic_perform_write(iocb, from)
...
->write_begin() <- does this block?
...
->write_end() <- or this one?
...
balance_dirty_pages_ratelimited() <- this one surely does...
If you look just one level down the latter to
balance_dirty_pages_ratelimited_flags(), you'll even see the 'flags'
argument documented there.
This looks pretty haphazard and cannot possibly work as-is, so please
get this reverted until f2fs is converted to iomap, or IOCB_NOWAIT is
handled by generic_perform_write() and below.
--
Jens Axboe
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next reply other threads:[~2023-06-19 22:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-19 20:43 Jens Axboe [this message]
2023-06-20 6:16 ` [f2fs-dev] f2fs async buffered write patch Jaegeuk Kim
2023-06-20 13:09 ` Jens Axboe
2023-06-26 7:31 ` Yangtao Li via Linux-f2fs-devel
2023-06-26 12:16 ` Matthew Wilcox
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