[Cluster-devel] [PATCH] unlock page lock before doing a dq

[Cluster-devel] [PATCH] unlock page lock before doing a dq

[Josef Bacik]

Hello,

There is a lockup condition where we get an error while perparing to write (such
as ENOSPC) and we go to do the gfs2_glock_dq_m and the glock has been marked
dirty.  Since we are already holding the page lock, we will deadlock because we
will try to flush all the pages back to disk and try to take the pagelock again.
Wendy you said I would be doing this in a transaction, but if there as error
inside where we started the transaction, we goto out, where we stop the
transaction first and then go on and unlock the page.  This fixes RH bz 280791.
Thank you,

Josef

--- 18.34/fs/gfs2/ops_address.c.josef	2007-09-07 15:07:03.000000000 -0400
+++ 18.34/fs/gfs2/ops_address.c	2007-09-07 15:12:45.000000000 -0400
@@ -457,8 +457,10 @@ out_alloc_put:
 			gfs2_alloc_put(ip);
 		}
 out_unlock:
+		unlock_page(page);
 		gfs2_glock_dq_m(1, &ip->i_gh);
 		gfs2_holder_uninit(&ip->i_gh);
+		lock_page(page);
 	}
 
 	return error;

[Cluster-devel] [PATCH] unlock page lock before doing a dq

[Steven Whitehouse]

Hi,

The bug has been verified not to exist on the latest kernel, so I don't
think we need this patch,

Steve.

On Sat, 2007-09-08 at 10:25 -0400, Josef Bacik wrote:
> Hello,
> 
> There is a lockup condition where we get an error while perparing to write (such
> as ENOSPC) and we go to do the gfs2_glock_dq_m and the glock has been marked
> dirty.  Since we are already holding the page lock, we will deadlock because we
> will try to flush all the pages back to disk and try to take the pagelock again.
> Wendy you said I would be doing this in a transaction, but if there as error
> inside where we started the transaction, we goto out, where we stop the
> transaction first and then go on and unlock the page.  This fixes RH bz 280791.
> Thank you,
> 
> Josef
> 
> --- 18.34/fs/gfs2/ops_address.c.josef	2007-09-07 15:07:03.000000000 -0400
> +++ 18.34/fs/gfs2/ops_address.c	2007-09-07 15:12:45.000000000 -0400
> @@ -457,8 +457,10 @@ out_alloc_put:
>  			gfs2_alloc_put(ip);
>  		}
>  out_unlock:
> +		unlock_page(page);
>  		gfs2_glock_dq_m(1, &ip->i_gh);
>  		gfs2_holder_uninit(&ip->i_gh);
> +		lock_page(page);
>  	}
>  
>  	return error;
>