From: Greg KH <gregkh@linuxfoundation.org>
To: John Donnelly <John.P.donnelly@oracle.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Mike Snitzer <snitzer@redhat.com>
Subject: Re: [PATCH v2: [linux-4.14.y] ] dm cache: submit writethrough writes in parallel to origin and cache
Date: Fri, 31 Jul 2020 08:54:31 +0200 [thread overview]
Message-ID: <20200731065431.GB1518178@kroah.com> (raw)
In-Reply-To: <48659508-86e7-8107-75db-584b2896ad48@oracle.com>
On Thu, Jul 30, 2020 at 03:33:42PM -0500, John Donnelly wrote:
> From: Mike Snitzer <snitzer@redhat.com>
>
> Discontinue issuing writethrough write IO in series to the origin and
> then cache.
>
> Use bio_clone_fast() to create a new origin clone bio that will be
> mapped to the origin device and then bio_chain() it to the bio that gets
> remapped to the cache device. The origin clone bio does _not_ have a
> copy of the per_bio_data -- as such check_if_tick_bio_needed() will not
> be called.
>
> The cache bio (parent bio) will not complete until the origin bio has
> completed -- this fulfills bio_clone_fast()'s requirements as well as
> the requirement to not complete the original IO until the write IO has
> completed to both the origin and cache device.
>
> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
>
> (cherry picked from commit 2df3bae9a6543e90042291707b8db0cbfbae9ee9)
>
> Fixes: 4ec34f2196d125ff781170ddc6c3058c08ec5e73 (dm bio record:
> save/restore bi_end_io and bi_integrity )
>
> 4ec34f21 introduced a mkfs.ext4 hang on a LVM device that has been
> modified with lvconvert --cachemode=writethrough.
>
> CC:stable@vger.kernel.org for 4.14.x .
>
> Signed-off-by: John Donnelly <john.p.donnelly@oracle.com>
> Reviewed-by: Somasundaram Krishnasamy <somasundaram.krishnasamy@oracle.com>
>
> conflicts:
> drivers/md/dm-cache-target.c. - Corrected usage of
> writethrough_mode(&cache->feature) that was caught by
> compiler, and removed unused static functions : writethrough_endio(),
> defer_writethrough_bio(), wake_deferred_writethrough_worker()
> that generated warnings.
> ---
> drivers/md/dm-cache-target.c | 94
> ++++++++++++++++++--------------------------
Line wrapped?
> 1 file changed, 38 insertions(+), 56 deletions(-)
>
> diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
> index 69cdb29ef6be..2d9566bfe08b 100644
> --- a/drivers/md/dm-cache-target.c
> +++ b/drivers/md/dm-cache-target.c
> @@ -1,5 +1,5 @@
> /*
> - * Copyright (C) 2012 Red Hat. All rights reserved.
> + i Copyright (C) 2012 Red Hat. All rights reserved.
What happened here?
This patch can't be applied as-is :(
greg k-h
next prev parent reply other threads:[~2020-07-31 6:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-30 20:33 [PATCH v2: [linux-4.14.y] ] dm cache: submit writethrough writes in parallel to origin and cache John Donnelly
2020-07-31 6:54 ` Greg KH [this message]
2020-07-31 14:35 ` John Donnelly
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