On Fri, Oct 02, 2009 at 04:24:39PM +0200, Bas Couwenberg wrote:
> Dear Christoph,
> Yesterday two of our servers (22.214.171.124 + your patch) crashed again, this
> time we have a bigger console, but not the full backtrace unfortunately.
> I did manage to get some more calltrace info from the logs, which I have
> attached together with the screenshots of the crashscreens.
> I hope this info helps you.
It helps a bit, but not so much. I suspect it could be a double free
of an inode, and I have identified a possible race window that could
explain it. But all the traces are really weird and I think only show
later symptoms of something that happened earlier. I'll come up with
a patch for the race window ASAP, but could you in the meantime turn on
CONFIG_XFS_DEBUG for the test kernel to see if it triggers somehwere
and additionally apply the tiny patch below for additional debugging?
Subject: xfs: check for not fully initialized inodes in xfs_ireclaim
From: Christoph Hellwig <hch@xxxxxx>
Add an assert for inodes not added to the inode cache in xfs_ireclaim, to make
sure we're not going to introduce something like the famous nfsd inode cache
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
--- linux-2.6.orig/fs/xfs/xfs_iget.c 2009-08-10 11:30:55.729724742 -0300
+++ linux-2.6/fs/xfs/xfs_iget.c 2009-08-10 11:40:15.271748324 -0300
@@ -535,17 +535,21 @@ xfs_ireclaim(
struct xfs_mount *mp = ip->i_mount;
struct xfs_perag *pag;
+ xfs_agino_t agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
- * Remove the inode from the per-AG radix tree. It doesn't matter
- * if it was never added to it because radix_tree_delete can deal
- * with that case just fine.
+ * Remove the inode from the per-AG radix tree.
+ * Because radix_tree_delete won't complain even if the item was never
+ * added to the tree assert that it's been there before to catch
+ * problems with the inode life time early on.
pag = xfs_get_perag(mp, ip->i_ino);
- radix_tree_delete(&pag->pag_ici_root, XFS_INO_TO_AGINO(mp, ip->i_ino));
+ ASSERT(radix_tree_lookup(&pag->pag_ici_root, agino));
+ radix_tree_delete(&pag->pag_ici_root, agino);