This patch removes the ls_remove_wait waitqueue handling. The current
handling tries to wait before a lookup is send out for a identically
resource name which is going to be removed. Hereby the remove message
should be send out before the new lookup message. The reason is that
after a lookup request and response will actually use the specific
remote rsb. A followed remove message would delete the rsb on the remote
side but it's still being used.
To reach a similar behaviour we simple send the remove message out while
the rsb lookup lock is held and the rsb is removed from the toss list.
Other find_rsb() calls would never have the change to get a rsb back to
live while a remove message will be send out (without holding the lock).
This behaviour requires a non-sleepable context which should be provided
now and might be the reason why it was not implemented so in the first
place.
Signed-off-by: Alexander Aring <aahri...@redhat.com>
---
fs/dlm/dlm_internal.h | 4 ----
fs/dlm/lock.c | 56 ++-----------------------------------------
fs/dlm/lockspace.c | 3 ---
3 files changed, 2 insertions(+), 61 deletions(-)
diff --git a/fs/dlm/dlm_internal.h b/fs/dlm/dlm_internal.h
index 0f32c780ce2c..a2cd4f291fd5 100644
--- a/fs/dlm/dlm_internal.h
+++ b/fs/dlm/dlm_internal.h
@@ -592,11 +592,7 @@ struct dlm_ls {
int ls_new_rsb_count;
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;
int ls_remove_lens[DLM_REMOVE_NAMES_MAX];
struct list_head ls_nodes; /* current nodes in ls */
diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 52bdaca400f4..3454fe3971a2 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -1590,37 +1590,6 @@ static int remove_from_waiters_ms(struct dlm_lkb *lkb,
struct dlm_message *ms)
return error;
}
-/* If there's an rsb for the same resource being removed, ensure
- * 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 (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);
- wait_event(ls->ls_remove_wait, !DLM_WAIT_PENDING_COND(ls, r));
- goto restart;
- }
- spin_unlock(&ls->ls_remove_spin);
-}
-
-/*
- * ls_remove_spin protects ls_remove_name and ls_remove_len which are
- * read by other threads in wait_pending_remove. ls_remove_names
- * and ls_remove_lens are only used by the scan thread, so they do
- * not need protection.
- */
-
static void shrink_bucket(struct dlm_ls *ls, int b)
{
struct rb_node *n, *next;
@@ -1702,11 +1671,6 @@ static void shrink_bucket(struct dlm_ls *ls, int b)
* list and sending the removal. Keeping this gap small is
* important to keep us (the master node) from being out of sync
* with the remote dir node for very long.
- *
- * From the time the rsb is removed from toss until just after
- * send_remove, the rsb name is saved in ls_remove_name. A new
- * lookup checks this to ensure that a new lookup message for the
- * same resource name is not sent just before the remove message.
*/
for (i = 0; i < remote_count; i++) {
@@ -1753,22 +1717,8 @@ static void shrink_bucket(struct dlm_ls *ls, int b)
}
rb_erase(&r->res_hashnode, &ls->ls_rsbtbl[b].toss);
-
- /* block lookup of same name until we've sent remove */
- spin_lock(&ls->ls_remove_spin);
- ls->ls_remove_len = len;
- memcpy(ls->ls_remove_name, name, DLM_RESNAME_MAXLEN);
- spin_unlock(&ls->ls_remove_spin);
- spin_unlock(&ls->ls_rsbtbl[b].lock);
-
send_remove(r);
-
- /* allow lookup of name again */
- spin_lock(&ls->ls_remove_spin);
- ls->ls_remove_len = 0;
- memset(ls->ls_remove_name, 0, DLM_RESNAME_MAXLEN);
- spin_unlock(&ls->ls_remove_spin);
- wake_up(&ls->ls_remove_wait);
+ spin_unlock(&ls->ls_rsbtbl[b].lock);
dlm_free_rsb(r);
}
@@ -2719,8 +2669,6 @@ static int set_master(struct dlm_rsb *r, struct dlm_lkb
*lkb)
return 0;
}
- wait_pending_remove(r);
-
r->res_first_lkid = lkb->lkb_id;
send_lookup(r, lkb);
return 1;
@@ -3814,7 +3762,7 @@ static int send_remove(struct dlm_rsb *r)
to_nodeid = dlm_dir_nodeid(r);
error = create_message(r, NULL, to_nodeid, DLM_MSG_REMOVE, &ms, &mh,
- GFP_NOFS);
+ GFP_ATOMIC);
if (error)
goto out;
diff --git a/fs/dlm/lockspace.c b/fs/dlm/lockspace.c
index 72fa8a9d7a40..c438b909f221 100644
--- a/fs/dlm/lockspace.c
+++ b/fs/dlm/lockspace.c
@@ -524,9 +524,6 @@ static int new_lockspace(const char *name, const char
*cluster,
spin_lock_init(&ls->ls_rsbtbl[i].lock);
}
- 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,
GFP_KERNEL);
--
2.31.1
