On Wed, Oct 22, 2008 at 06:58:38PM +1100, Dave Chinner wrote:
> On Tue, Oct 21, 2008 at 03:42:16PM +0400, Alexander Beregalov wrote:
> > Bisected to:
> > dd509097cb0b76d3836385f80d6b2d6fd3b97757 is first bad commit
> > commit dd509097cb0b76d3836385f80d6b2d6fd3b97757
> > Author: Lachlan McIlroy <lachlan@xxxxxxx>
> > Date: Mon Sep 29 14:56:40 2008 +1000
> >
> > [XFS] Unlock inode before calling xfs_idestroy()
> >
> > Lock debugging reported the ilock was being destroyed without being
> > unlocked. We don't need to lock the inode until we are going to insert it
> > into the radix tree.
>
> Ah, OK, I see the problem, though I don't understand why I'm not
> seeing the might_sleep() triggering all the time given that I always
> build with:
>
> $ grep SLEEP .config
> CONFIG_DEBUG_SPINLOCK_SLEEP=y
>
> Basically the above commit moved xfs_ilock() inside
> radix_tree_preload()/radix_tree_preload_end(), which means we are
> taking a rwsem() while we have an elevated preempt count. I'll
> get a patch out to fix it.
Patch below (against the xfs master/linux-next branch) should fix the
regression. I've just started QA on it. Can you please check that
it works for you, Alexander?
Cheers,
Dave.
--
Dave Chinner
david@xxxxxxxxxxxxx
XFS: Can't lock inodes in radix tree preload region
When we are inside a radix tree preload region, we cannot
sleep. Recently we moved the inode locking inside the
preload region for the inode radix tree. Fix that,
and fix a missed unlock in another error path in the
same code at the same time.
Signed-off-by: Dave Chinner <david@xxxxxxxxxxxxx>
---
fs/xfs/xfs_iget.c | 18 +++++++++++-------
1 files changed, 11 insertions(+), 7 deletions(-)
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index fbc6088..837cae7 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -159,18 +159,19 @@ xfs_iget_cache_miss(
goto out_destroy;
}
+ if (lock_flags)
+ xfs_ilock(ip, lock_flags);
+
/*
* Preload the radix tree so we can insert safely under the
- * write spinlock.
+ * write spinlock. Note that we cannot sleep inside the preload
+ * region.
*/
if (radix_tree_preload(GFP_KERNEL)) {
error = EAGAIN;
- goto out_destroy;
+ goto out_unlock;
}
- if (lock_flags)
- xfs_ilock(ip, lock_flags);
-
mask = ~(((XFS_INODE_CLUSTER_SIZE(mp) >> mp->m_sb.sb_inodelog)) - 1);
first_index = agino & mask;
write_lock(&pag->pag_ici_lock);
@@ -181,7 +182,7 @@ xfs_iget_cache_miss(
WARN_ON(error != -EEXIST);
XFS_STATS_INC(xs_ig_dup);
error = EAGAIN;
- goto out_unlock;
+ goto out_preload_end;
}
/* These values _must_ be set before releasing the radix tree lock! */
@@ -193,9 +194,12 @@ xfs_iget_cache_miss(
*ipp = ip;
return 0;
-out_unlock:
+out_preload_end:
write_unlock(&pag->pag_ici_lock);
radix_tree_preload_end();
+out_unlock:
+ if (lock_flags)
+ xfs_iunlock(ip, lock_flags);
out_destroy:
xfs_destroy_inode(ip);
return error;
--
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