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fs: dlm: use event based wait for pending remove

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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: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>
This commit is contained in:
Alexander Aring 2021-11-30 14:47:16 -05:00 committed by David Teigland
parent bcbfea41e1
commit 21d9ac1a53
3 changed files with 14 additions and 7 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
fs/dlm/dlm_internal.h
View file

@ -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;

19
fs/dlm/lock.c
View file

@ -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);
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);

1
fs/dlm/lockspace.c
View file

@ -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,