From: Li Zefan <lizf@cn.fujitsu.com>
To: Sage Weil <sage@newdream.net>
Cc: "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH] Btrfs: fix pages truncation in btrfs_ioctl_clone()
Date: Mon, 19 Sep 2011 11:07:14 +0800 [thread overview]
Message-ID: <4E76B1E2.3070402@cn.fujitsu.com> (raw)
In-Reply-To: <Pine.LNX.4.64.1109160934590.11043@cobra.newdream.net>
>> Also move the function before locking extent state.
>
> Hmm, any reason? i_mutex protects us from a racing write(2), but what
> about a racing mmap()? e.g.
>
> cloner: truncates dest pages
> writer: mmap -> page_mkwrite locks extent, creates new dirty page, unlocks
> cloner: locks extent, clones, unlocks extent
>
(besides Chris' comments)
How can we avoid the race on dst file by locking src file extent state..
--
Li Zefan
prev parent reply other threads:[~2011-09-19 3:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-16 8:59 [PATCH] Btrfs: fix pages truncation in btrfs_ioctl_clone() Li Zefan
2011-09-16 16:39 ` Sage Weil
2011-09-18 15:31 ` Chris Mason
2011-09-19 5:40 ` Sage Weil
2011-09-19 3:07 ` Li Zefan [this message]
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