From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f177.google.com (mail-ie0-f177.google.com [209.85.223.177]) by kanga.kvack.org (Postfix) with ESMTP id 648716B0031 for ; Thu, 17 Apr 2014 23:56:46 -0400 (EDT) Received: by mail-ie0-f177.google.com with SMTP id rl12so1223124iec.36 for ; Thu, 17 Apr 2014 20:56:46 -0700 (PDT) Received: from mail-ie0-x22f.google.com (mail-ie0-x22f.google.com [2607:f8b0:4001:c03::22f]) by mx.google.com with ESMTPS id nz8si17672259icb.33.2014.04.17.20.56.45 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 17 Apr 2014 20:56:45 -0700 (PDT) Received: by mail-ie0-f175.google.com with SMTP id to1so1219413ieb.34 for ; Thu, 17 Apr 2014 20:56:45 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <000c01cf1b47$ce280170$6a780450$%yang@samsung.com> <20140203153628.5e186b0e4e81400773faa7ac@linux-foundation.org> Date: Fri, 18 Apr 2014 11:56:45 +0800 Message-ID: Subject: Re: [PATCH 3/8] mm/swap: prevent concurrent swapon on the same S_ISBLK blockdev From: Weijie Yang Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: Andrew Morton , Weijie Yang , Minchan Kim , shli@kernel.org, Bob Liu , Seth Jennings , Heesub Shin , mquzik@redhat.com, Linux-MM , linux-kernel On Tue, Feb 4, 2014 at 12:20 PM, Hugh Dickins wrote: > On Mon, 3 Feb 2014, Andrew Morton wrote: >> On Mon, 27 Jan 2014 18:03:04 +0800 Weijie Yang 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? > > That answer makes me sad: we can't be bothered to get it right, > even when Weijie goes to the trouble of presenting a series to do so. > But I sure don't deserve a vote until I've actually looked through it. > Hi, This is a ping email. Could I get some options about these patch series? Thanks. > Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org