From: Jens Axboe <axboe@kernel.dk>
To: Christoph Hellwig <hch@infradead.org>,
Anju T Sudhakar <anju@linux.vnet.ibm.com>
Cc: darrick.wong@oracle.com, linux-xfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
willy@infradead.org, riteshh@linux.ibm.com,
linux-block@vger.kernel.org
Subject: Re: [PATCH] iomap: Fix the write_count in iomap_add_to_ioend().
Date: Fri, 21 Aug 2020 08:49:48 -0600 [thread overview]
Message-ID: <9bf274cb-15ec-f389-42b3-b8469402af3d@kernel.dk> (raw)
In-Reply-To: <20200821060710.GC31091@infradead.org>
On 8/21/20 12:07 AM, Christoph Hellwig wrote:
> On Wed, Aug 19, 2020 at 03:58:41PM +0530, Anju T Sudhakar wrote:
>> From: Ritesh Harjani <riteshh@linux.ibm.com>
>>
>> __bio_try_merge_page() may return same_page = 1 and merged = 0.
>> This could happen when bio->bi_iter.bi_size + len > UINT_MAX.
>> Handle this case in iomap_add_to_ioend() by incrementing write_count.
>> This scenario mostly happens where we have too much dirty data accumulated.
>>
>> w/o the patch we hit below kernel warning,
>
> I think this is better fixed in the block layer rather than working
> around the problem in the callers. Something like this:
>
> diff --git a/block/bio.c b/block/bio.c
> index c63ba04bd62967..ef321cd1072e4e 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -879,8 +879,10 @@ bool __bio_try_merge_page(struct bio *bio, struct page *page,
> struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];
>
> if (page_is_mergeable(bv, page, len, off, same_page)) {
> - if (bio->bi_iter.bi_size > UINT_MAX - len)
> + if (bio->bi_iter.bi_size > UINT_MAX - len) {
> + *same_page = false;
> return false;
> + }
> bv->bv_len += len;
> bio->bi_iter.bi_size += len;
> return true;
>
This looks good to me.
--
Jens Axboe
next prev parent reply other threads:[~2020-08-21 14:49 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 10:28 [PATCH] iomap: Fix the write_count in iomap_add_to_ioend() Anju T Sudhakar
2020-08-20 23:11 ` Dave Chinner
2020-08-21 4:45 ` Ritesh Harjani
2020-08-21 6:00 ` Christoph Hellwig
2020-08-21 9:09 ` Ritesh Harjani
2020-08-21 21:53 ` Dave Chinner
2020-08-22 13:13 ` Christoph Hellwig
2020-08-24 14:28 ` Brian Foster
2020-08-24 15:04 ` Christoph Hellwig
2020-08-24 15:48 ` Brian Foster
2020-08-25 0:42 ` Dave Chinner
2020-08-25 14:49 ` Brian Foster
2020-08-31 4:01 ` Ming Lei
2020-08-31 14:35 ` Brian Foster
2020-09-16 0:12 ` Darrick J. Wong
2020-09-16 8:45 ` Christoph Hellwig
2020-09-16 13:07 ` Brian Foster
2020-09-17 8:04 ` Christoph Hellwig
2020-09-17 10:42 ` Brian Foster
2020-09-17 14:48 ` Christoph Hellwig
2020-09-17 21:33 ` Darrick J. Wong
2020-09-17 23:13 ` Ming Lei
2020-08-21 6:01 ` Christoph Hellwig
2020-08-21 6:07 ` Christoph Hellwig
2020-08-21 8:53 ` Ritesh Harjani
2020-08-21 14:49 ` Jens Axboe [this message]
2020-08-21 13:31 ` Matthew Wilcox
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=9bf274cb-15ec-f389-42b3-b8469402af3d@kernel.dk \
--to=axboe@kernel.dk \
--cc=anju@linux.vnet.ibm.com \
--cc=darrick.wong@oracle.com \
--cc=hch@infradead.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-xfs@vger.kernel.org \
--cc=riteshh@linux.ibm.com \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).