Re: xfs deadlock in stable kernel 3.0.4

Christoph Hellwig
2011-09-13T20:50:24Z

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