Messages in this thread | | | Date | Mon, 3 Feb 2014 15:36:28 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 3/8] mm/swap: prevent concurrent swapon on the same S_ISBLK blockdev |
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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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