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From: Miklos Szeredi <mszeredi@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Amir Goldstein <amir73il@gmail.com>
Subject: Re: [PATCH 1/3] vfs: dedpue: return s64
Date: Mon, 7 May 2018 13:32:09 +0200	[thread overview]
Message-ID: <CAOssrKebppZhRbvM-3qk=S0aY57skYCEn2axknOtF9LcJcu8yA@mail.gmail.com> (raw)
In-Reply-To: <20180507111142.GA18116@bombadil.infradead.org>

On Mon, May 7, 2018 at 1:11 PM, Matthew Wilcox <willy@infradead.org> wrote:
> On Mon, May 07, 2018 at 10:21:06AM +0200, Miklos Szeredi wrote:
>> f_op->dedupe_file_range() gets a u64 length to dedup and returns an ssize_t
>> actual length deduped.  This breaks badly on 32bit archs since the returned
>> length will be truncated and possibly overflow into the sign bit (xfs and
>> ocfs2 are affected, btrfs limits actual length to 16MiB).
>>
>> Returning s64 should be good, since clone_verify_area() makes sure that the
>> supplied length doesn't overflow.
>
> Why s64 rather than loff_t?  Particularly since the next patch turns
> the paramters into loff_t.

Next patch turns the offsets into loff_t and leaves "len" as u64.  A
size is definitely not an offset, I'd consider changing the type of
"len" to loff_t a misuse.

Thanks,
Miklos

  reply	other threads:[~2018-05-07 11:32 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-07  8:21 [PATCH 0/3] vfs: dedupe: cleanup API and implementation Miklos Szeredi
2018-05-07  8:21 ` [PATCH 1/3] vfs: dedpue: return s64 Miklos Szeredi
2018-05-07 11:11   ` Matthew Wilcox
2018-05-07 11:32     ` Miklos Szeredi [this message]
2018-05-07 12:17       ` Matthew Wilcox
2018-05-07 14:26         ` Miklos Szeredi
2018-05-07  8:21 ` [PATCH 2/3] vfs: dedupe: rationalize args Miklos Szeredi
2018-05-07 11:16   ` Matthew Wilcox
2018-05-07 11:36     ` Miklos Szeredi
2018-05-07  8:21 ` [PATCH 3/3] vfs: dedupe: extract helper for a single dedup Miklos Szeredi

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