[Cluster-devel] [PATCH] dlm: send_bast_queue() skip list loop not only sending basts to convertqueue
David Teigland
teigland at redhat.com
Tue Jan 4 21:27:38 UTC 2011
On Tue, Jan 04, 2011 at 06:06:51PM -0200, cmaiolino at redhat.com wrote:
> The resource groups got corrupted without this patch:
I could see an extraneous bast leading to confusion in gfs2 about the lock
state, but gfs2 should probably be asserting somewhere before it actually
corrupts anything...
> diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
> index 64e5f3e..565c519 100644
> --- a/fs/dlm/lock.c
> +++ b/fs/dlm/lock.c
> @@ -1847,7 +1847,7 @@ static void send_bast_queue(struct dlm_rsb *r, struct list_head *head,
>
> list_for_each_entry(gr, head, lkb_statequeue) {
> /* skip self when sending basts to convertqueue */
> - if (gr == lkb)
> + if (head == &r->res_grantqueue && gr == lkb)
> continue;
> if (gr->lkb_bastfn && modes_require_bast(gr, lkb)) {
> queue_bast(r, gr, lkb->lkb_rqmode);
I haven't been able to figure out the problem or the fix; some printk's
around the case in question would be revealing.
This is the specific case where a TRY_1CB (NOQUEUBAST) conversion fails.
Here's how I step through the code for that case:
_convert_lock(lkb)
error = do_convert(lkb)
when error equals -EAGAIN, lkb remains on grantqueue
do_convert_effects(lkb, -EAGAIN)
-EAGAIN and NOQUEUEBAST -> send_blocking_asts_all ->
send_bast_queue(grantqueue, lkb)
[lkb is expected to be here, skip sending bast to self]
send_bast_queue(convertqueue, lkb):
[lkb should not be on here, but your patch implies there
are cases where it can be? I think that would be a bug.]
Dave
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