Hi,
On Thu, Jul 13, 2023 at 1:08 PM Alexander Aring <aahri...@redhat.com> wrote:
>
> This patch implements DLM_PLOCK_OP_CANCEL to try to delete waiters for a
> lock request which are waiting to being granted. If the waiter can be
> deleted the reply to the kernel will be replaced from
> DLM_PLOCK_OP_LOCK to the sent DLM_PLOCK_OP_CANCEL and clearing the
> DLM_PLOCK_FL_NO_REPLY flag.
> ---
> dlm_controld/plock.c | 47 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
> diff --git a/dlm_controld/plock.c b/dlm_controld/plock.c
> index ab19e8d7..fd2bd2cf 100644
> --- a/dlm_controld/plock.c
> +++ b/dlm_controld/plock.c
> @@ -9,6 +9,10 @@
> #include "dlm_daemon.h"
> #include <linux/dlm_plock.h>
>
> +#ifndef DLM_PLOCK_OP_CANCEL
> +#define DLM_PLOCK_OP_CANCEL 4
> +#endif
> +
> #ifndef DLM_PLOCK_FL_NO_REPLY
> #define DLM_PLOCK_FL_NO_REPLY 2
> #endif
> @@ -136,6 +140,8 @@ static const char *op_str(int optype)
> switch (optype) {
> case DLM_PLOCK_OP_LOCK:
> return "LK";
> + case DLM_PLOCK_OP_CANCEL:
> + return "CL";
> case DLM_PLOCK_OP_UNLOCK:
> return "UN";
> case DLM_PLOCK_OP_GET:
> @@ -751,6 +757,43 @@ static void do_lock(struct lockspace *ls, struct
> dlm_plock_info *in,
> put_resource(ls, r);
> }
>
> +static int remove_waiter(const struct resource *r, struct dlm_plock_info *in)
> +{
> + struct lock_waiter *w;
> +
> + list_for_each_entry(w, &r->waiters, list) {
> + if (w->info.nodeid == in->nodeid &&
> + w->info.fsid == in->fsid &&
> + w->info.number == in->number &&
> + w->info.owner == in->owner &&
> + w->info.pid == in->pid &&
> + w->info.start == in->start &&
> + w->info.end == in->end &&
> + w->info.ex == in->ex) {
> + list_del(&w->list);
> + free(w);
> + return 0;
> + }
> + }
> +
> + return -ENOENT;
> +}
> +
> +static void do_cancel(struct lockspace *ls, struct dlm_plock_info *in,
> + struct resource *r)
> +{
> + int rv;
> +
> + rv = remove_waiter(r, in);
> + if (in->nodeid == our_nodeid && rv == 0) {
> + /* we replacing a reply because we canceled waiter */
> + in->flags &= ~DLM_PLOCK_FL_NO_REPLY;
I think we should do a copy of "in" here and then clear the flag... it
can have side effects if the ongoing processing will then call
write_result().
At some point dlm_plock_info should be const here...
- Alex
