From: Andrew Morton <akpm@linux-foundation.org>
To: Weijie Yang <weijie.yang@samsung.com>
Cc: hughd@google.com, 'Minchan Kim' <minchan@kernel.org>,
shli@kernel.org, 'Bob Liu' <bob.liu@oracle.com>,
weijie.yang.kh@gmail.com,
'Seth Jennings' <sjennings@variantweb.net>,
'Heesub Shin' <heesub.shin@samsung.com>,
mquzik@redhat.com, 'Linux-MM' <linux-mm@kvack.org>,
'linux-kernel' <linux-kernel@vger.kernel.org>,
stable@vger.kernel.org
Subject: Re: [PATCH 3/8] mm/swap: prevent concurrent swapon on the same S_ISBLK blockdev
Date: Mon, 3 Feb 2014 15:36:28 -0800 [thread overview]
Message-ID: <20140203153628.5e186b0e4e81400773faa7ac@linux-foundation.org> (raw)
In-Reply-To: <000c01cf1b47$ce280170$6a780450$%yang@samsung.com>
On Mon, 27 Jan 2014 18:03:04 +0800 Weijie Yang <weijie.yang@samsung.com> wrote:
> When swapon the same S_ISBLK blockdev concurrent, the allocated two
> swap_info could hold the same block_device, because claim_swapfile()
> allow the same holder(here, it is sys_swapon function).
>
> To prevent this situation, This patch adds swap_lock protect to ensure
> we can find this situation and return -EBUSY for one swapon call.
>
> As for S_ISREG swapfile, claim_swapfile() already prevent this scenario
> by holding inode->i_mutex.
>
> This patch is just for a rare scenario, aim to correct of code.
>
hm, OK. Would it be saner to pass a unique `holder' to
claim_swapfile()? Say, `p'?
Truly, I am fed up with silly swapon/swapoff races. How often does
anyone call these things? Let's slap a huge lock around the whole
thing and be done with it?
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next prev parent reply other threads:[~2014-02-03 23:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-27 10:03 Weijie Yang
2014-02-03 23:36 ` Andrew Morton [this message]
2014-02-04 4:20 ` Hugh Dickins
2014-04-18 3:56 ` Weijie Yang
2014-04-18 20:01 ` Hugh Dickins
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