EXIT;
}
-static void lovsub_parent_lock(const struct lu_env *env, struct lov_lock *lov)
-{
- struct cl_lock *parent;
-
- ENTRY;
- parent = lov->lls_cl.cls_lock;
- cl_lock_get(parent);
- lu_ref_add(&parent->cll_reference, "lovsub-parent", current);
- cl_lock_mutex_get(env, parent);
- EXIT;
-}
-
-static void lovsub_parent_unlock(const struct lu_env *env, struct lov_lock *lov)
-{
- struct cl_lock *parent;
-
- ENTRY;
- parent = lov->lls_cl.cls_lock;
- cl_lock_mutex_put(env, lov->lls_cl.cls_lock);
- lu_ref_del(&parent->cll_reference, "lovsub-parent", current);
- cl_lock_put(env, parent);
- EXIT;
-}
-
-/**
- * Implements cl_lock_operations::clo_state() method for lovsub layer, which
- * method is called whenever sub-lock state changes. Propagates state change
- * to the top-locks.
- */
-static void lovsub_lock_state(const struct lu_env *env,
- const struct cl_lock_slice *slice,
- enum cl_lock_state state)
-{
- struct lovsub_lock *sub = cl2lovsub_lock(slice);
- struct lov_lock_link *scan;
-
- LASSERT(cl_lock_is_mutexed(slice->cls_lock));
- ENTRY;
-
- list_for_each_entry(scan, &sub->lss_parents, lll_list) {
- struct lov_lock *lov = scan->lll_super;
- struct cl_lock *parent = lov->lls_cl.cls_lock;
-
- if (sub->lss_active != parent) {
- lovsub_parent_lock(env, lov);
- cl_lock_signal(env, parent);
- lovsub_parent_unlock(env, lov);
- }
- }
- EXIT;
-}
-
-/**
- * Implementation of cl_lock_operation::clo_weigh() estimating lock weight by
- * asking parent lock.
- */
-static unsigned long lovsub_lock_weigh(const struct lu_env *env,
- const struct cl_lock_slice *slice)
-{
- struct lovsub_lock *lock = cl2lovsub_lock(slice);
- struct lov_lock *lov;
- unsigned long dumbbell;
-
- ENTRY;
-
- LASSERT(cl_lock_is_mutexed(slice->cls_lock));
-
- if (!list_empty(&lock->lss_parents)) {
- /*
- * It is not clear whether all parents have to be asked and
- * their estimations summed, or it is enough to ask one. For
- * the current usages, one is always enough.
- */
- lov = container_of(lock->lss_parents.next,
- struct lov_lock_link, lll_list)->lll_super;
-
- lovsub_parent_lock(env, lov);
- dumbbell = cl_lock_weigh(env, lov->lls_cl.cls_lock);
- lovsub_parent_unlock(env, lov);
- } else
- dumbbell = 0;
-
- RETURN(dumbbell);
-}
-
-/**
- * Maps start/end offsets within a stripe, to offsets within a file.
- */
-static void lovsub_lock_descr_map(const struct cl_lock_descr *in,
- struct lov_object *lov,
- int stripe, struct cl_lock_descr *out)
-{
- pgoff_t size; /* stripe size in pages */
- pgoff_t skip; /* how many pages in every stripe are occupied by
- * "other" stripes */
- pgoff_t start;
- pgoff_t end;
-
- ENTRY;
- start = in->cld_start;
- end = in->cld_end;
-
- if (lov->lo_lsm->lsm_stripe_count > 1) {
- size = cl_index(lov2cl(lov), lov->lo_lsm->lsm_stripe_size);
- skip = (lov->lo_lsm->lsm_stripe_count - 1) * size;
-
- /* XXX overflow check here? */
- start += start/size * skip + stripe * size;
-
- if (end != CL_PAGE_EOF) {
- end += end/size * skip + stripe * size;
- /*
- * And check for overflow...
- */
- if (end < in->cld_end)
- end = CL_PAGE_EOF;
- }
- }
- out->cld_start = start;
- out->cld_end = end;
- EXIT;
-}
-
-/**
- * Adjusts parent lock extent when a sub-lock is attached to a parent. This is
- * called in two ways:
- *
- * - as part of receive call-back, when server returns granted extent to
- * the client, and
- *
- * - when top-lock finds existing sub-lock in the cache.
- *
- * Note, that lock mode is not propagated to the parent: i.e., if CLM_READ
- * top-lock matches CLM_WRITE sub-lock, top-lock is still CLM_READ.
- */
-int lov_sublock_modify(const struct lu_env *env, struct lov_lock *lov,
- struct lovsub_lock *sublock,
- const struct cl_lock_descr *d, int idx)
-{
- struct cl_lock *parent;
- struct lovsub_object *subobj;
- struct cl_lock_descr *pd;
- struct cl_lock_descr *parent_descr;
- int result;
-
- parent = lov->lls_cl.cls_lock;
- parent_descr = &parent->cll_descr;
- LASSERT(cl_lock_mode_match(d->cld_mode, parent_descr->cld_mode));
-
- subobj = cl2lovsub(sublock->lss_cl.cls_obj);
- pd = &lov_env_info(env)->lti_ldescr;
-
- pd->cld_obj = parent_descr->cld_obj;
- pd->cld_mode = parent_descr->cld_mode;
- pd->cld_gid = parent_descr->cld_gid;
- lovsub_lock_descr_map(d, subobj->lso_super, subobj->lso_index, pd);
-
- /* LU-3027: only update extent of lock, plus the change in
- * lovsub_lock_delete() that lock extent is modified after a sublock
- * is canceled, we can make sure that the lock extent won't be updated
- * any more. Therefore, lov_lock_fits_into() will always find feasible
- * locks */
- lov->lls_sub[idx].sub_got.cld_start = d->cld_start;
- lov->lls_sub[idx].sub_got.cld_end = d->cld_end;
- /*
- * Notify top-lock about modification, if lock description changes
- * materially.
- */
- if (!cl_lock_ext_match(parent_descr, pd))
- result = cl_lock_modify(env, parent, pd);
- else
- result = 0;
- return result;
-}
-
-static int lovsub_lock_modify(const struct lu_env *env,
- const struct cl_lock_slice *s,
- const struct cl_lock_descr *d)
-{
- struct lovsub_lock *lock = cl2lovsub_lock(s);
- struct lov_lock_link *scan;
- struct lov_lock *lov;
- int result = 0;
-
- ENTRY;
-
- LASSERT(cl_lock_mode_match(d->cld_mode,
- s->cls_lock->cll_descr.cld_mode));
- list_for_each_entry(scan, &lock->lss_parents, lll_list) {
- int rc;
-
- lov = scan->lll_super;
- lovsub_parent_lock(env, lov);
- rc = lov_sublock_modify(env, lov, lock, d, scan->lll_idx);
- lovsub_parent_unlock(env, lov);
- result = result ?: rc;
- }
- RETURN(result);
-}
-
-static int lovsub_lock_closure(const struct lu_env *env,
- const struct cl_lock_slice *slice,
- struct cl_lock_closure *closure)
-{
- struct lovsub_lock *sub;
- struct cl_lock *parent;
- struct lov_lock_link *scan;
- int result;
-
- LASSERT(cl_lock_is_mutexed(slice->cls_lock));
- ENTRY;
-
- sub = cl2lovsub_lock(slice);
- result = 0;
-
- list_for_each_entry(scan, &sub->lss_parents, lll_list) {
- parent = scan->lll_super->lls_cl.cls_lock;
- result = cl_lock_closure_build(env, parent, closure);
- if (result != 0)
- break;
- }
- RETURN(result);
-}
-
-/**
- * A helper function for lovsub_lock_delete() that deals with a given parent
- * top-lock.
- */
-static int lovsub_lock_delete_one(const struct lu_env *env,
- struct cl_lock *child, struct lov_lock *lov)
-{
- struct cl_lock *parent;
- int result;
- ENTRY;
-
- parent = lov->lls_cl.cls_lock;
- if (parent->cll_error)
- RETURN(0);
-
- result = 0;
- lov->lls_ever_canceled = 1;
- switch (parent->cll_state) {
- case CLS_ENQUEUED:
- /* See LU-1355 for the case that a glimpse lock is
- * interrupted by signal */
- LASSERT(parent->cll_flags & CLF_CANCELLED);
- break;
- case CLS_QUEUING:
- case CLS_FREEING:
- cl_lock_signal(env, parent);
- break;
- case CLS_INTRANSIT:
- /*
- * Here lies a problem: a sub-lock is canceled while top-lock
- * is being unlocked. Top-lock cannot be moved into CLS_NEW
- * state, because unlocking has to succeed eventually by
- * placing lock into CLS_CACHED (or failing it), see
- * cl_unuse_try(). Nor can top-lock be left in CLS_CACHED
- * state, because lov maintains an invariant that all
- * sub-locks exist in CLS_CACHED (this allows cached top-lock
- * to be reused immediately). Nor can we wait for top-lock
- * state to change, because this can be synchronous to the
- * current thread.
- *
- * We know for sure that lov_lock_unuse() will be called at
- * least one more time to finish un-using, so leave a mark on
- * the top-lock, that will be seen by the next call to
- * lov_lock_unuse().
- */
- if (cl_lock_is_intransit(parent))
- lov->lls_cancel_race = 1;
- break;
- case CLS_CACHED:
- /*
- * if a sub-lock is canceled move its top-lock into CLS_NEW
- * state to preserve an invariant that a top-lock in
- * CLS_CACHED is immediately ready for re-use (i.e., has all
- * sub-locks), and so that next attempt to re-use the top-lock
- * enqueues missing sub-lock.
- */
- cl_lock_state_set(env, parent, CLS_NEW);
- /* fall through */
- case CLS_NEW:
- /*
- * if last sub-lock is canceled, destroy the top-lock (which
- * is now `empty') proactively.
- */
- if (lov->lls_nr_filled == 0) {
- /* ... but unfortunately, this cannot be done easily,
- * as cancellation of a top-lock might acquire mutices
- * of its other sub-locks, violating lock ordering,
- * see cl_lock_{cancel,delete}() preconditions.
- *
- * To work around this, the mutex of this sub-lock is
- * released, top-lock is destroyed, and sub-lock mutex
- * acquired again. The list of parents has to be
- * re-scanned from the beginning after this.
- *
- * Only do this if no mutices other than on @child and
- * @parent are held by the current thread.
- *
- * TODO: The lock modal here is too complex, because
- * the lock may be canceled and deleted by voluntarily:
- * cl_lock_request
- * -> osc_lock_enqueue_wait
- * -> osc_lock_cancel_wait
- * -> cl_lock_delete
- * -> lovsub_lock_delete
- * -> cl_lock_cancel/delete
- * -> ...
- *
- * The better choice is to spawn a kernel thread for
- * this purpose. -jay
- */
- if (cl_lock_nr_mutexed(env) == 2) {
- cl_lock_mutex_put(env, child);
- cl_lock_cancel(env, parent);
- cl_lock_delete(env, parent);
- result = 1;
- }
- }
- break;
- case CLS_HELD:
- CL_LOCK_DEBUG(D_ERROR, env, parent, "Delete CLS_HELD lock\n");
- /* falling through */
- default:
- CERROR("Impossible state: %d\n", parent->cll_state);
- LBUG();
- break;
- }
-
- RETURN(result);
-}
-
-/**
- * An implementation of cl_lock_operations::clo_delete() method. This is
- * invoked in "bottom-to-top" delete, when lock destruction starts from the
- * sub-lock (e.g, as a result of ldlm lock LRU policy).
- */
-static void lovsub_lock_delete(const struct lu_env *env,
- const struct cl_lock_slice *slice)
-{
- struct cl_lock *child = slice->cls_lock;
- struct lovsub_lock *sub = cl2lovsub_lock(slice);
- int restart;
-
- LASSERT(cl_lock_is_mutexed(child));
-
- ENTRY;
- /*
- * Destruction of a sub-lock might take multiple iterations, because
- * when the last sub-lock of a given top-lock is deleted, top-lock is
- * canceled proactively, and this requires to release sub-lock
- * mutex. Once sub-lock mutex has been released, list of its parents
- * has to be re-scanned from the beginning.
- */
- do {
- struct lov_lock *lov;
- struct lov_lock_link *scan;
- struct lov_lock_link *temp;
-
- restart = 0;
- list_for_each_entry_safe(scan, temp,
- &sub->lss_parents, lll_list) {
- lov = scan->lll_super;
- lovsub_parent_lock(env, lov);
- lov_lock_unlink(env, scan, sub);
- restart = lovsub_lock_delete_one(env, child, lov);
- lovsub_parent_unlock(env, lov);
-
- if (restart) {
- cl_lock_mutex_get(env, child);
- break;
- }
- }
- } while (restart);
- EXIT;
-}
-
-static int lovsub_lock_print(const struct lu_env *env, void *cookie,
- lu_printer_t p, const struct cl_lock_slice *slice)
-{
- struct lovsub_lock *sub = cl2lovsub_lock(slice);
- struct lov_lock *lov;
- struct lov_lock_link *scan;
-
- list_for_each_entry(scan, &sub->lss_parents, lll_list) {
- lov = scan->lll_super;
- (*p)(env, cookie, "[%d %p ", scan->lll_idx, lov);
- if (lov != NULL)
- cl_lock_descr_print(env, cookie, p,
- &lov->lls_cl.cls_lock->cll_descr);
- (*p)(env, cookie, "] ");
- }
- return 0;
-}
-
static const struct cl_lock_operations lovsub_lock_ops = {
.clo_fini = lovsub_lock_fini,
- .clo_state = lovsub_lock_state,
- .clo_delete = lovsub_lock_delete,
- .clo_modify = lovsub_lock_modify,
- .clo_closure = lovsub_lock_closure,
- .clo_weigh = lovsub_lock_weigh,
- .clo_print = lovsub_lock_print
};
int lovsub_lock_init(const struct lu_env *env, struct cl_object *obj,
git://git.whamcloud.com / fs / lustre-release.git / blobdiff