From 21d9ac1a5376d949199398848006f6b14649f533 Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Tue, 30 Nov 2021 14:47:16 -0500 Subject: [PATCH] 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: Alexander Aring Signed-off-by: David Teigland --- fs/dlm/dlm_internal.h | 1 + fs/dlm/lock.c | 19 ++++++++++++------- fs/dlm/lockspace.c | 1 + 3 files changed, 14 insertions(+), 7 deletions(-) diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h index 019931804af9..74a9590a4dd5 100644 --- a/fs/dlm/dlm_internal.h +++ b/fs/dlm/dlm_internal.h @@ -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; diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c index 54705d367076..bdb51d209ba2 100644 --- a/fs/dlm/lock.c +++ b/fs/dlm/lock.c @@ -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); diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c index 2e51bd2bdacc..31384e7d6f90 100644 --- a/fs/dlm/lockspace.c +++ b/fs/dlm/lockspace.c @@ -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,