Commit 21d9ac1a authored by Alexander Aring's avatar Alexander Aring Committed by David Teigland
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fs: dlm: use event based wait for pending remove 



This patch will use an event based waitqueue to wait for a possible clash
with the ls_remove_name field of dlm_ls instead of doing busy waiting.

Signed-off-by: default avatarAlexander Aring <aahringo@redhat.com>
Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
parent bcbfea41

fs/dlm/dlm_internal.h

+1 −0
Original line number Diff line number Diff line
@@ -576,6 +576,7 @@ struct dlm_ls { 
	struct list_head	ls_new_rsb;	/* new rsb structs */



	spinlock_t		ls_remove_spin;

	wait_queue_head_t	ls_remove_wait;

	char			ls_remove_name[DLM_RESNAME_MAXLEN+1];

	char			*ls_remove_names[DLM_REMOVE_NAMES_MAX];

	int			ls_remove_len;

fs/dlm/lock.c

+12 −7
Original line number Diff line number Diff line
@@ -1626,21 +1626,24 @@ static int remove_from_waiters_ms(struct dlm_lkb *lkb, struct dlm_message *ms) 
}



/* If there's an rsb for the same resource being removed, ensure

   that the remove message is sent before the new lookup message.

   It should be rare to need a delay here, but if not, then it may

   be worthwhile to add a proper wait mechanism rather than a delay. */

 * that the remove message is sent before the new lookup message.

 */



#define DLM_WAIT_PENDING_COND(ls, r)		\

	(ls->ls_remove_len &&			\

	 !rsb_cmp(r, ls->ls_remove_name,	\

		  ls->ls_remove_len))



static void wait_pending_remove(struct dlm_rsb *r)

{

	struct dlm_ls *ls = r->res_ls;

 restart:

	spin_lock(&ls->ls_remove_spin);

	if (ls->ls_remove_len &&

	    !rsb_cmp(r, ls->ls_remove_name, ls->ls_remove_len)) {

	if (DLM_WAIT_PENDING_COND(ls, r)) {

		log_debug(ls, "delay lookup for remove dir %d %s",

			  r->res_dir_nodeid, r->res_name);

		spin_unlock(&ls->ls_remove_spin);

		msleep(1);

		wait_event(ls->ls_remove_wait, !DLM_WAIT_PENDING_COND(ls, r));

		goto restart;

	}

	spin_unlock(&ls->ls_remove_spin);
@@ -1792,6 +1795,7 @@ static void shrink_bucket(struct dlm_ls *ls, int b) 
		memcpy(ls->ls_remove_name, name, DLM_RESNAME_MAXLEN);

		spin_unlock(&ls->ls_remove_spin);

		spin_unlock(&ls->ls_rsbtbl[b].lock);

		wake_up(&ls->ls_remove_wait);



		send_remove(r);
@@ -4075,6 +4079,7 @@ static void send_repeat_remove(struct dlm_ls *ls, char *ms_name, int len) 
	memcpy(ls->ls_remove_name, name, DLM_RESNAME_MAXLEN);

	spin_unlock(&ls->ls_remove_spin);

	spin_unlock(&ls->ls_rsbtbl[b].lock);

	wake_up(&ls->ls_remove_wait);



	rv = _create_message(ls, sizeof(struct dlm_message) + len,

			     dir_nodeid, DLM_MSG_REMOVE, &ms, &mh);

fs/dlm/lockspace.c

+1 −0
Original line number Diff line number Diff line
@@ -512,6 +512,7 @@ static int new_lockspace(const char *name, const char *cluster, 
	}



	spin_lock_init(&ls->ls_remove_spin);

	init_waitqueue_head(&ls->ls_remove_wait);



	for (i = 0; i < DLM_REMOVE_NAMES_MAX; i++) {

		ls->ls_remove_names[i] = kzalloc(DLM_RESNAME_MAXLEN+1,