ldlm_mode_t req_mode = req->l_req_mode;
__u64 req_start = req->l_req_extent.start;
__u64 req_end = req->l_req_extent.end;
+ int conflicting = 0;
ENTRY;
lockmode_verify(req_mode);
if (req == lock)
continue;
+ /* Locks are compatible, overlap doesn't matter */
+ /* Until bug 20 is fixed, try to avoid granting overlapping
+ * locks on one client (they take a long time to cancel) */
+ if (lockmode_compat(lock->l_req_mode, req_mode) &&
+ lock->l_export != req->l_export)
+ continue;
+
+ /* If this is a high-traffic lock, don't grow downwards at all
+ * or grow upwards too much */
+ ++conflicting;
+ if (conflicting > 4)
+ new_ex->start = req_start;
+
/* If lock doesn't overlap new_ex, skip it. */
if (l_extent->end < new_ex->start ||
l_extent->start > new_ex->end)
continue;
- /* Locks are compatible, overlap doesn't matter */
- if (lockmode_compat(lock->l_req_mode, req_mode))
- continue;
-
/* Locks conflicting in requested extents and we can't satisfy
* both locks, so ignore it. Either we will ping-pong this
* extent (we would regardless of what extent we granted) or
/* We grow extents downwards only as far as they don't overlap
* with already-granted locks, on the assumtion that clients
* will be writing beyond the initial requested end and would
- * then need to enqueue a new lock beyond the previous request.
- * We don't grow downwards if there are lots of lockers. */
- if (l_extent->start < req_start) {
- if (atomic_read(&req->l_resource->lr_refcount) > 20)
+ * then need to enqueue a new lock beyond previous request.
+ * l_req_extent->end strictly < req_start, checked above. */
+ if (l_extent->start < req_start && new_ex->start != req_start) {
+ if (l_extent->end >= req_start)
new_ex->start = req_start;
else
new_ex->start = min(l_extent->end+1, req_start);
new_ex->end = max(l_extent->start - 1, req_end);
}
}
+
+#define LDLM_MAX_GROWN_EXTENT (32 * 1024 * 1024 - 1)
+ if (conflicting > 32 && (req_mode == LCK_PW || req_mode == LCK_CW)) {
+ if (req_end < req_start + LDLM_MAX_GROWN_EXTENT)
+ new_ex->end = min(req_start + LDLM_MAX_GROWN_EXTENT,
+ new_ex->end);
+ }
EXIT;
}
{
struct ldlm_extent new_ex = { .start = 0, .end = ~0};
+ if (lock->l_req_mode == LCK_GROUP)
+ return;
+
ldlm_extent_internal_policy(&res->lr_granted, lock, &new_ex);
ldlm_extent_internal_policy(&res->lr_waiting, lock, &new_ex);
*/
static int
ldlm_extent_compat_queue(struct list_head *queue, struct ldlm_lock *req,
- int send_cbs, int *flags, ldlm_error_t *err)
+ int *flags, struct list_head *work_list,
+ struct list_head **insertp)
{
struct list_head *tmp;
- struct ldlm_lock *lock;
+ struct list_head *save = NULL;
+ struct ldlm_lock *lock = NULL;
ldlm_mode_t req_mode = req->l_req_mode;
- __u64 req_start = req->l_req_extent.start;
- __u64 req_end = req->l_req_extent.end;
int compat = 1;
+ int found = 0;
ENTRY;
lockmode_verify(req_mode);
+ /* Extent locks are only queued once. We can get back here with
+ * insertp != NULL if the blocking ASTs returned -ERESTART. */
+ if (!list_empty(&req->l_res_link))
+ insertp = NULL;
+
+ if (req->l_req_mode != LCK_GROUP) {
+ __u64 req_start = req->l_req_extent.start;
+ __u64 req_end = req->l_req_extent.end;
+
+ list_for_each(tmp, queue) {
+ lock = list_entry(tmp, struct ldlm_lock, l_res_link);
+ if (req == lock)
+ break;
+
+ if (lock->l_req_mode == LCK_GROUP) {
+ if (*flags & LDLM_FL_BLOCK_NOWAIT)
+ RETURN(-EWOULDBLOCK);
+
+ /* No blocking ASTs are sent for group locks. */
+ compat = 0;
+
+ /* there's a blocking group lock in front
+ * of us on the queue. It can be held
+ * indefinitely, so don't timeout. */
+ if (insertp) {
+ *flags |= LDLM_FL_NO_TIMEOUT;
+ /* lock_bitlock(req) is held here. */
+ req->l_flags |= LDLM_FL_NO_TIMEOUT;
+ }
+
+ if (work_list)
+ continue;
+ else
+ break;
+ }
+
+ /* locks are compatible, overlap doesn't matter */
+ if (lockmode_compat(lock->l_req_mode, req_mode))
+ continue;
+
+ if (lock->l_policy_data.l_extent.end < req_start ||
+ lock->l_policy_data.l_extent.start > req_end)
+ continue;
+
+ compat = 0;
+
+ if (!work_list)
+ break;
+
+ if (lock->l_blocking_ast)
+ ldlm_add_ast_work_item(lock, req, work_list);
+ }
+
+ if (insertp)
+ *insertp = queue;
+
+ RETURN(compat);
+ }
+
list_for_each(tmp, queue) {
lock = list_entry(tmp, struct ldlm_lock, l_res_link);
-
if (req == lock)
- RETURN(compat);
+ break;
+
+ if (lock->l_req_mode != LCK_GROUP) {
+ if (lock->l_req_mode != lock->l_granted_mode) {
+ /* we must be traversing the waitq. */
+
+ /* If a group lock was already found then
+ * req can be queued before any extent locks
+ * that come after the found group lock. */
+ if (found)
+ break;
+
+ if (!insertp) {
+ /* We've hit a conflicting extent lock
+ * on the waitq before hitting the req
+ * group lock. See comments below. */
+ compat = 0;
+ break;
+ }
- /* locks are compatible, overlap doesn't matter */
- if (lockmode_compat(lock->l_req_mode, req_mode)) {
- /* nonCW locks are compatible, overlap doesn't matter */
- if (req_mode != LCK_CW)
- continue;
-
- /* If we are trying to get a CW lock and there is
- another one of this kind, we need to compare gid */
- if (req->l_policy_data.l_extent.gid ==
- lock->l_policy_data.l_extent.gid) {
- if (lock->l_req_mode == lock->l_granted_mode)
- RETURN(2);
-
- /* If we are in nonblocking mode - return
- immediately */
- if (*flags & LDLM_FL_BLOCK_NOWAIT) {
- compat = -EWOULDBLOCK;
- goto destroylock;
+ /* Group locks are not normally blocked by
+ * waiting PR|PW locks. */
+
+ /* If NO_TIMEOUT was sent back to the client
+ * we can queue the group lock in front of
+ * this extent lock. */
+ if (lock->l_flags & LDLM_FL_NO_TIMEOUT) {
+ if (save == NULL)
+ save = tmp;
+ continue;
}
- /* If this group lock is compatible with another
- * group lock on the waiting list, they must be
- * together in the list, so they can be granted
- * at the same time. Otherwise the later lock
- * can get stuck behind another, incompatible,
- * lock. */
- ldlm_resource_insert_lock_after(lock, req);
- /* Because 'lock' is not granted, we can stop
- * processing this queue and return immediately.
- * There is no need to check the rest of the
- * list. */
- RETURN(0);
+
+ /* If we did NOT send NO_TIMEOUT back to the
+ * client for this extent lock then the client
+ * could possibly timeout if we queue this
+ * group lock before it, so don't. This is the
+ * only way to get a conflicting extent lock
+ * in front of a group lock on the waitq. */
+ }
+
+ compat = 0;
+ if (!work_list) {
+ LASSERT(save == NULL);
+ break;
}
- }
- if (lock->l_req_mode == LCK_CW) {
- /* If compared lock is CW, then requested is PR/PW/ =>
- * this is not compatible; extent range does not
- * matter */
- if (*flags & LDLM_FL_BLOCK_NOWAIT) {
- compat = -EWOULDBLOCK;
- goto destroylock;
- } else {
- *flags |= LDLM_FL_NO_TIMEOUT;
+ /* If we previously skipped over some extent locks
+ * because we thought we were going to queue the
+ * group lock in front of them then we need to go back
+ * and send blocking ASTs for the locks we skipped. */
+ if (save != NULL) {
+ struct ldlm_lock *lck2;
+
+ for (; save != tmp; save = save->next) {
+ lck2 = list_entry(save,
+ struct ldlm_lock,
+ l_res_link);
+
+ /* If there was a group lock after save
+ * then we would have exited this loop
+ * above. */
+ LASSERT(lck2->l_req_mode!=LCK_GROUP);
+
+ if (lck2->l_blocking_ast) {
+ ldlm_add_ast_work_item(lck2,req,
+ work_list);
+ }
+ }
+ save = NULL;
}
- } else if (lock->l_policy_data.l_extent.end < req_start ||
- lock->l_policy_data.l_extent.start > req_end) {
- /* if a non-CW lock doesn't overlap skip it */
+
+ if (lock->l_blocking_ast)
+ ldlm_add_ast_work_item(lock, req, work_list);
continue;
}
- if (!send_cbs)
- RETURN(0);
+ /* If it was safe to insert a group lock at save,
+ * i.e. save != NULL, then this group lock already
+ * on the queue would have been inserted before save. */
+ LASSERT(save == NULL);
+
+ /* Note: no blocking ASTs are sent for group locks. */
+
+ if (lock->l_policy_data.l_extent.gid ==
+ req->l_policy_data.l_extent.gid) {
+ /* group locks with this gid already on the waitq. */
+ found = 2;
+
+ if (lock->l_req_mode == lock->l_granted_mode) {
+ /* if a group lock with this gid has already
+ * been granted then grant this one. */
+ compat = 2;
+ break;
+ }
+ } else {
+ if (found == 2)
+ break;
+
+ /* group locks already exist on the queue. */
+ found = 1;
- compat = 0;
- if (lock->l_blocking_ast)
- ldlm_add_ast_work_item(lock, req, NULL, 0);
+ if (*flags & LDLM_FL_BLOCK_NOWAIT)
+ RETURN(-EWOULDBLOCK);
+
+ compat = 0;
+
+ /* there's a blocking group lock in front
+ * of us on the queue. It can be held
+ * indefinitely, so don't timeout. */
+ *flags |= LDLM_FL_NO_TIMEOUT;
+
+ /* the only reason to continue traversing the
+ * list at this point is to find the proper
+ * place to insert the lock in the waitq. */
+ if (!insertp)
+ break;
+ }
+ }
+
+ if (insertp != NULL) {
+ if (save != NULL)
+ *insertp = save;
+ else
+ *insertp = tmp;
}
- return(compat);
-destroylock:
- list_del_init(&req->l_res_link);
- ldlm_lock_destroy(req);
- *err = compat;
RETURN(compat);
}
* - the caller has NOT initialized req->lr_tmp, so we must
* - must call this function with the ns lock held once */
int ldlm_process_extent_lock(struct ldlm_lock *lock, int *flags, int first_enq,
- ldlm_error_t *err)
+ ldlm_error_t *err, struct list_head *work_list)
{
struct ldlm_resource *res = lock->l_resource;
struct list_head rpc_list = LIST_HEAD_INIT(rpc_list);
+ struct list_head *insertp = NULL;
int rc, rc2;
ENTRY;
*err = ELDLM_OK;
if (!first_enq) {
- /* Careful observers will note that we don't handle -EWOULDBLOCK
- * here, but it's ok for a non-obvious reason -- compat_queue
- * can only return -EWOULDBLOCK if (flags & BLOCK_NOWAIT).
- * flags should always be zero here, and if that ever stops
- * being true, we want to find out. */
+ /* -EWOULDBLOCK can't occur here since (flags & BLOCK_NOWAIT)
+ * lock requests would either be granted or fail on their
+ * first_enq. flags should always be zero here, and if that
+ * ever changes we want to find out. */
LASSERT(*flags == 0);
- LASSERT(res->lr_tmp != NULL);
- rc = ldlm_extent_compat_queue(&res->lr_granted, lock, 0, flags,
- err);
+ rc = ldlm_extent_compat_queue(&res->lr_granted, lock,
+ flags, NULL, NULL);
if (rc == 1) {
- rc = ldlm_extent_compat_queue(&res->lr_waiting, lock, 0,
- flags, err);
+ rc = ldlm_extent_compat_queue(&res->lr_waiting, lock,
+ flags, NULL, NULL);
}
if (rc == 0)
RETURN(LDLM_ITER_STOP);
ldlm_resource_unlink_lock(lock);
-
ldlm_extent_policy(res, lock, flags);
- ldlm_grant_lock(lock, NULL, 0, 1);
+ lock_bitlock(lock);
+ lock->l_flags &= ~LDLM_FL_NO_TIMEOUT;
+ unlock_bitlock(lock);
+ ldlm_grant_lock(lock, work_list);
RETURN(LDLM_ITER_CONTINUE);
}
restart:
- LASSERT(res->lr_tmp == NULL);
- res->lr_tmp = &rpc_list;
- rc = ldlm_extent_compat_queue(&res->lr_granted, lock, 1, flags, err);
+ rc = ldlm_extent_compat_queue(&res->lr_granted, lock, flags, &rpc_list,
+ NULL);
if (rc < 0)
- RETURN(rc); /* lock was destroyed */
+ GOTO(destroylock, rc);
if (rc == 2)
goto grant;
- rc2 = ldlm_extent_compat_queue(&res->lr_waiting, lock, 1, flags, err);
+ /* Traverse the waiting list in case there are other conflicting
+ * lock requests ahead of us in the queue and send blocking ASTs */
+ rc2 = ldlm_extent_compat_queue(&res->lr_waiting, lock, flags, &rpc_list,
+ &insertp);
if (rc2 < 0)
- RETURN(rc2); /* lock was destroyed */
- res->lr_tmp = NULL;
-
+ GOTO(destroylock, rc);
if (rc + rc2 == 2) {
- grant:
+ grant:
ldlm_extent_policy(res, lock, flags);
ldlm_resource_unlink_lock(lock);
- ldlm_grant_lock(lock, NULL, 0, 0);
+ lock->l_flags &= ~LDLM_FL_NO_TIMEOUT;
+ ldlm_grant_lock(lock, NULL);
} else {
/* If either of the compat_queue()s returned failure, then we
* have ASTs to send and must go onto the waiting list.
* terrible folly -- if we goto restart, we could get
* re-ordered! Causes deadlock, because ASTs aren't sent! */
if (list_empty(&lock->l_res_link))
- ldlm_resource_add_lock(res, &res->lr_waiting, lock);
- l_unlock(&res->lr_namespace->ns_lock);
- rc = ldlm_run_ast_work(res->lr_namespace, &rpc_list);
- l_lock(&res->lr_namespace->ns_lock);
+ ldlm_resource_add_lock(res, insertp, lock);
+ unlock_res(res);
+ rc = ldlm_run_bl_ast_work(&rpc_list);
+ lock_res(res);
if (rc == -ERESTART)
GOTO(restart, -ERESTART);
*flags |= LDLM_FL_BLOCK_GRANTED;
}
+
RETURN(0);
+
+ destroylock:
+ list_del_init(&lock->l_res_link);
+ unlock_res(res);
+ ldlm_lock_destroy(lock);
+ lock_res(res);
+ *err = rc;
+ RETURN(rc);
}
/* When a lock is cancelled by a client, the KMS may undergo change if this
* is the "highest lock". This function returns the new KMS value.
+ * Caller must hold ns_lock already.
*
* NB: A lock on [x,y] protects a KMS of up to y + 1 bytes! */
__u64 ldlm_extent_shift_kms(struct ldlm_lock *lock, __u64 old_kms)
__u64 kms = 0;
ENTRY;
- l_lock(&res->lr_namespace->ns_lock);
+ /* don't let another thread in ldlm_extent_shift_kms race in
+ * just after we finish and take our lock into account in its
+ * calculation of the kms */
+
+ lock->l_flags |= LDLM_FL_KMS_IGNORE;
+
list_for_each(tmp, &res->lr_granted) {
lck = list_entry(tmp, struct ldlm_lock, l_res_link);
- if (lock == lck)
+ if (lck->l_flags & LDLM_FL_KMS_IGNORE)
continue;
+
if (lck->l_policy_data.l_extent.end >= old_kms)
- GOTO(out, kms = old_kms);
- kms = lck->l_policy_data.l_extent.end + 1;
+ RETURN(old_kms);
+
+ /* This extent _has_ to be smaller than old_kms (checked above)
+ * so kms can only ever be smaller or the same as old_kms. */
+ if (lck->l_policy_data.l_extent.end + 1 > kms)
+ kms = lck->l_policy_data.l_extent.end + 1;
}
+ LASSERTF(kms <= old_kms, "kms "LPU64" old_kms "LPU64"\n", kms, old_kms);
- GOTO(out, kms);
- out:
- l_unlock(&res->lr_namespace->ns_lock);
- return kms;
+ RETURN(kms);
}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff