From: Christoph Hellwig <hch@infradead.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Yu Kuai <yukuai1@huaweicloud.com>,
axboe@kernel.dk, rajeevm@hpe.com, yukuai3@huawei.com,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
yi.zhang@huawei.com, yangerkun@huawei.com,
johnny.chenyi@huawei.com, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] loop: fix zero sized loop for block special file
Date: Mon, 25 Aug 2025 02:18:09 -0700 [thread overview]
Message-ID: <aKwqUVmX-yH6_lZy@infradead.org> (raw)
In-Reply-To: <aKwlVypJuBtPH_EL@fedora>
On Mon, Aug 25, 2025 at 04:56:55PM +0800, Ming Lei wrote:
> `stat $BDEV_PATH` never works for getting bdev size, so it looks wrong
> to call vfs_getattr_nosec() with bdev path for retrieving bdev's size.
Exactly.
> So just wondering why not take the following more readable way?
>
> /* vfs_getattr() never works for retrieving bdev size */
> if (S_ISBLK(stat.mode)) {
> loopsize = i_size_read(file->f_mapping->host);
> } else {
> ret = vfs_getattr_nosec(&file->f_path, &stat, STATX_SIZE, 0);
> if (ret)
> return 0;
> loopsize = stat.size;
> }
>
> Also the above looks like how application reads file size in case of bdev
> involved.
That's not just more readable, but simply the way to go. Maybe split
it into a helper for readability, though.
next prev parent reply other threads:[~2025-08-25 9:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20250825062300.2485281-1-yukuai1@huaweicloud.com>
2025-08-25 8:56 ` [PATCH] loop: fix zero sized loop for block special file Ming Lei
2025-08-25 9:18 ` Christoph Hellwig [this message]
2025-08-25 9:36 ` Yu Kuai
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