This is a note to let you know that we have just queued up the patch titled
Subject: xfs: eagerly remove vmap mappings to avoid upsetting Xen
to the 2.6.23-stable tree. Its filename is
xen-xfs-unmap.patch
A git repo of this tree can be found at
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
>From [email protected] Fri Oct 12 14:33:36 2007
From: Jeremy Fitzhardinge <[email protected]>
Date: Fri, 12 Oct 2007 14:11:42 -0700
Subject: xfs: eagerly remove vmap mappings to avoid upsetting Xen
To: LKML <[email protected]>
Cc: [email protected], [email protected], Mark Williamson <[email protected]>, XFS masters <[email protected]>, Chris Wright <[email protected]>, Andi Kleen <[email protected]>, Morten Bøgeskov <[email protected]>, Andrew Morton <[email protected]>, Keir Fraser <[email protected]>, Stable kernel <[email protected]>
Message-ID: <[email protected]>
Content-Disposition: inline; filename=xen-xfs-unmap.patch
From: Jeremy Fitzhardinge <[email protected]>
patch ace2e92e193126711cb3a83a3752b2c5b8396950 in mainline.
XFS leaves stray mappings around when it vmaps memory to make it
virtually contigious. This upsets Xen if one of those pages is being
recycled into a pagetable, since it finds an extra writable mapping of
the page.
This patch solves the problem in a brute force way, by making XFS
always eagerly unmap its mappings.
[ Stable: This works around a bug in 2.6.23. We may come up with a
better solution for mainline, but this seems like a low-impact fix for
the stable kernel. ]
Signed-off-by: Jeremy Fitzhardinge <[email protected]>
Cc: XFS masters <[email protected]>
Cc: Morten =?utf-8?q?B=C3=B8geskov?= <[email protected]>
Cc: Mark Williamson <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/xfs/linux-2.6/xfs_buf.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
--- a/fs/xfs/linux-2.6/xfs_buf.c
+++ b/fs/xfs/linux-2.6/xfs_buf.c
@@ -187,6 +187,19 @@ free_address(
{
a_list_t *aentry;
+#ifdef CONFIG_XEN
+ /*
+ * Xen needs to be able to make sure it can get an exclusive
+ * RO mapping of pages it wants to turn into a pagetable. If
+ * a newly allocated page is also still being vmap()ed by xfs,
+ * it will cause pagetable construction to fail. This is a
+ * quick workaround to always eagerly unmap pages so that Xen
+ * is happy.
+ */
+ vunmap(addr);
+ return;
+#endif
+
aentry = kmalloc(sizeof(a_list_t), GFP_NOWAIT);
if (likely(aentry)) {
spin_lock(&as_lock);
Patches currently in stable-queue which might be from [email protected] are
queue-2.6.23/xen-handle-lazy-cr3-on-unpin.patch
queue-2.6.23/xen-multicall-callbacks.patch
queue-2.6.23/xen-fix-register_vcpu_info.patch
queue-2.6.23/xen-xfs-unmap.patch
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