[Cluster-devel] [GFS2] Fix bz 231380, unlock page before dequeing glocks in gfs2_commit_write
Steven Whitehouse
swhiteho at redhat.com
Wed Mar 14 14:50:34 UTC 2007
Hi,
Now applied to the -nmw git tree. I think this is the right fix, at
least for now,
Steve.
On Mon, 2007-03-12 at 16:55 -0500, Josef Whiter wrote:
> Hello,
>
> I'm not entirely sure if this is the best fix for this problem, so I'm open for
> suggetions. If we are writing a file, and in the middle of writing the file
> another node attempts to get a shared lock on that file (by doing a du for
> example) the process doing the writing will hang waiting on lock_page. The
> reason for this is because when we have waiters on a exclusive glock, we will go
> through and flush out all dirty pages associated with that inode and release the
> lock. The problem is that when we flush the dirty pages, we could hit a page
> that we have locked durring the generic_file_buffered_write part of this
> operation. This patch unlocks the page before we go to dequeue the lock and
> locks it immediatly afterwards, since generic_file_buffered_write needs the page
> locked when the commit_write is completed. This patch resolves the problem,
> however if somebody sees a better way to do this please don't hesistate to yell.
> Thank you,
>
> Josef
>
>
> Signed-off-by: Josef Whiter <jwhiter at redhat.com>
>
>
> --- gfs2-2.6-nmw/fs/gfs2/ops_address.c.josef 2007-03-08 15:04:10.000000000 -0500
> +++ gfs2-2.6-nmw/fs/gfs2/ops_address.c 2007-03-12 17:23:24.000000000 -0400
> @@ -507,7 +507,9 @@
> gfs2_quota_unlock(ip);
> gfs2_alloc_put(ip);
> }
> + unlock_page(page);
> gfs2_glock_dq_m(1, &ip->i_gh);
> + lock_page(page);
> gfs2_holder_uninit(&ip->i_gh);
> return 0;
>
> @@ -520,7 +522,9 @@
> gfs2_quota_unlock(ip);
> gfs2_alloc_put(ip);
> }
> + unlock_page(page);
> gfs2_glock_dq_m(1, &ip->i_gh);
> + lock_page(page);
> gfs2_holder_uninit(&ip->i_gh);
> fail_nounlock:
> ClearPageUptodate(page);
>
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