xfs deadlock in stable kernel 3.0.4

[Christoph Hellwig]

On Tue, Sep 13, 2011 at 08:04:36AM +0200, Stefan Priebe - Profihost AG wrote:
> I just reported it to the scsi list as i didn't knew where the
> problems is. But then some people told be it must be a XFS problem.
> 
> Some more informations:
> 1.) It's running with 2.6.32 and 2.6.38
> 2.) I can also write to another ext2 part on the same disk
> array(aacraid driver) while xfs stucks - so i think it must be an
> xfs problem

That points a bit more towards XFS, although we've seen storage setups
create issues depending on the exact workload.  The prime culprit for
used to be the md software RAID driver, though.

> 3.) I've also tried running 3.1-rc5 but then i'm seeing this error:
> 
> BUG: unable to handle kernel NULL pointer dereference at 000000000000012c
> IP: [] inode_dio_done+0x4/0x25

Oops, that's a bug that I actually introduced myself.  Fix below:


Index: linux-2.6/fs/xfs/xfs_aops.c
===================================================================
--- linux-2.6.orig/fs/xfs/xfs_aops.c	2011-09-13 16:38:47.141089046 -0400
+++ linux-2.6/fs/xfs/xfs_aops.c	2011-09-13 16:39:09.991647077 -0400
@@ -1300,6 +1300,7 @@ xfs_end_io_direct_write(
 	bool			is_async)
 {
 	struct xfs_ioend	*ioend = iocb->private;
+	struct inode		*inode = ioend->io_inode;
 
 	/*
 	 * blockdev_direct_IO can return an error even after the I/O
@@ -1331,7 +1332,7 @@ xfs_end_io_direct_write(
 	}
 
 	/* XXX: probably should move into the real I/O completion handler */
-	inode_dio_done(ioend->io_inode);
+	inode_dio_done(inode);
 }
 
 STATIC ssize_t