From: Guoqing Jiang <guoqing.jiang@linux.dev>
To: song@kernel.org
Cc: linux-raid@vger.kernel.org, jens@chianterastutte.eu
Subject: Re: [PATCH 1/6] md/raid1: only allocate write behind bio for WriteMostly device
Date: Tue, 5 Oct 2021 09:05:30 +0800 [thread overview]
Message-ID: <f601dddd-1239-e7bd-7ce9-7c43845fbce5@linux.dev> (raw)
In-Reply-To: <20211004153453.14051-2-guoqing.jiang@linux.dev>
Now cc Jens actually.
On 10/4/21 11:34 PM, Guoqing Jiang wrote:
> Commit 6607cd319b6b91bff94e90f798a61c031650b514 ("raid1: ensure write
> behind bio has less than BIO_MAX_VECS sectors") tried to guarantee the
> size of behind bio is not bigger than BIO_MAX_VECS sectors.
>
> Unfortunately the same calltrace still could happen since an array could
> enable write-behind without write mostly device.
>
> To match the manpage of mdadm (which says "write-behind is only attempted
> on drives marked as write-mostly"), we need to check WriteMostly flag to
> avoid such unexpected behavior.
>
> [1]. https://bugzilla.kernel.org/show_bug.cgi?id=213181#c25
>
> Cc: stable@vger.kernel.org # v5.12+
> Cc: Jens Stutte <jens@chianterastutte.eu>
> Reported-by: Jens Stutte <jens@chianterastutte.eu>
> Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
> ---
> drivers/md/raid1.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
> index 19598bd38939..6ba12f0f0f03 100644
> --- a/drivers/md/raid1.c
> +++ b/drivers/md/raid1.c
> @@ -1496,7 +1496,7 @@ static void raid1_write_request(struct mddev *mddev, struct bio *bio,
> if (!r1_bio->bios[i])
> continue;
>
> - if (first_clone) {
> + if (first_clone && test_bit(WriteMostly, &rdev->flags)) {
> /* do behind I/O ?
> * Not if there are too many, or cannot
> * allocate memory, or a reader on WriteMostly
next prev parent reply other threads:[~2021-10-05 1:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-04 15:34 [PATCH 0/6] Misc changes for md Guoqing Jiang
2021-10-04 15:34 ` [PATCH 1/6] md/raid1: only allocate write behind bio for WriteMostly device Guoqing Jiang
2021-10-05 1:05 ` Guoqing Jiang [this message]
2021-10-05 5:55 ` Jens Stutte
2021-10-04 15:34 ` [PATCH 2/6] md/bitmap: don't set max_write_behind if there is no write mostly device Guoqing Jiang
2021-10-07 6:25 ` Song Liu
2021-10-07 10:20 ` Guoqing Jiang
2021-10-04 15:34 ` [PATCH 3/6] md/raid1: use rdev in raid1_write_request directly Guoqing Jiang
2021-10-04 15:34 ` [PATCH 4/6] md/raid10: add 'read_err' to raid10_read_request Guoqing Jiang
2021-10-07 6:20 ` Song Liu
2021-10-07 10:16 ` Guoqing Jiang
2021-10-04 15:34 ` [PATCH 5/6] md/raid5: call roundup_pow_of_two in raid5_run Guoqing Jiang
2021-10-04 15:34 ` [PATCH 6/6] md: remove unused argument from md_new_event Guoqing Jiang
2021-10-07 6:32 ` [PATCH 0/6] Misc changes for md Song Liu
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