From: Christoph Hellwig <hch@infradead.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Vivek Goyal <vgoyal@redhat.com>,
Pei Zhang <pezhang@redhat.com>
Subject: Re: [PATCH] block: loop: set discard_granularity as PAGE_SIZE if sb->s_blocksize is 0
Date: Mon, 24 Jan 2022 06:05:07 -0800 [thread overview]
Message-ID: <Ye6yE2Ephyv+WBYY@infradead.org> (raw)
In-Reply-To: <20220124100628.1327718-1-ming.lei@redhat.com>
On Mon, Jan 24, 2022 at 06:06:28PM +0800, Ming Lei wrote:
> If backing file's filesystem has implemented ->fallocate(), we think the
> loop device can support discard, then pass sb->s_blocksize as
> discard_granularity. However, some underlying FS, such as overlayfs,
> doesn't set sb->s_blocksize, and causes discard_granularity to be set as
> zero, then the warning in __blkdev_issue_discard() is triggered.
>
> Fix the issue by setting discard_granularity as PAGE_SIZE in this case
> since PAGE_SIZE is the most common data unit for FS.
sb->s_blocksize really does not mean anything. kstat.blksize might
be a better choice, even if it someimes errs on the too large side.
next prev parent reply other threads:[~2022-01-24 14:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 10:06 [PATCH] block: loop: set discard_granularity as PAGE_SIZE if sb->s_blocksize is 0 Ming Lei
2022-01-24 13:36 ` Vivek Goyal
2022-01-24 14:05 ` Christoph Hellwig [this message]
2022-01-24 15:22 ` Vivek Goyal
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