Commit 2d30d31e authored Apr 29, 2013 by Jerome Marchand Committed by Linus Torvalds Apr 29, 2013

swap: redirty page if page write fails on swap file



Since commit 62c230bc ("mm: add support for a filesystem to activate
swap files and use direct_IO for writing swap pages"), swap_writepage()
calls direct_IO on swap files.  However, in that case the page isn't
redirtied if I/O fails, and is therefore handled afterwards as if it has
been successfully written to the swap file, leading to memory corruption
when the page is eventually swapped back in.

This patch sets the page dirty when direct_IO() fails.  It fixes a
memory corruption that happened while using swap-over-NFS.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>	[3.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 465adcf1

mm/page_io.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -231,6 +231,8 @@ int __swap_writepage(struct page page, struct writeback_control wbc,
		if (ret == PAGE_SIZE) {
		count_vm_event(PSWPOUT);
		ret = 0;
		} else {
		set_page_dirty(page);
		}
		return ret;
		}

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