X-Git-Url: https://git.whamcloud.com/?a=blobdiff_plain;f=lustre%2Flov%2Flovsub_lock.c;h=6c3a6495ad21fbf4d933a05e6cb85c8907627112;hb=a52819c3f77022ca931cac47de68d46d160ff0aa;hp=f7d54ba46be4ce029adfcac46f07a841342f6151;hpb=48d29ff71de18d8d375b072a7287ba9ecdb6cdce;p=fs%2Flustre-release.git diff --git a/lustre/lov/lovsub_lock.c b/lustre/lov/lovsub_lock.c index f7d54ba..6c3a649 100644 --- a/lustre/lov/lovsub_lock.c +++ b/lustre/lov/lovsub_lock.c @@ -1,6 +1,4 @@ -/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*- - * vim:expandtab:shiftwidth=8:tabstop=8: - * +/* * GPL HEADER START * * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. @@ -28,6 +26,8 @@ /* * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved. * Use is subject to license terms. + * + * Copyright (c) 2011, 2014, Intel Corporation. */ /* * This file is part of Lustre, http://www.lustre.org/ @@ -59,425 +59,30 @@ static void lovsub_lock_fini(const struct lu_env *env, ENTRY; lsl = cl2lovsub_lock(slice); - LASSERT(cfs_list_empty(&lsl->lss_parents)); + LASSERT(list_empty(&lsl->lss_parents)); OBD_SLAB_FREE_PTR(lsl, lovsub_lock_kmem); 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", cfs_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", cfs_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; - - cfs_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 (!cfs_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 *obj, - int stripe, struct cl_lock_descr *out) -{ - struct lov_stripe_md *lsm = lov_r0(obj)->lo_lsm; - 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 (lsm->lsm_stripe_count > 1) { - size = cl_index(lov2cl(obj), lsm->lsm_stripe_size); - skip = (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 cl_lock *child; - 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)); - - child = sublock->lss_cl.cls_lock; - 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); - lov->lls_sub[idx].sub_got = *d; - /* - * 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)); - cfs_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; - - cfs_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; - switch (parent->cll_state) { - case CLS_NEW: - case CLS_QUEUING: - case CLS_ENQUEUED: - 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); - /* - * 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"); - 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; - struct lov_lock_sub *subdata; - - restart = 0; - cfs_list_for_each_entry_safe(scan, temp, - &sub->lss_parents, lll_list) { - lov = scan->lll_super; - subdata = &lov->lls_sub[scan->lll_idx]; - lovsub_parent_lock(env, lov); - subdata->sub_got = subdata->sub_descr; - 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; - - cfs_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, - struct cl_lock *lock, const struct cl_io *io) + struct cl_lock *lock, const struct cl_io *io) { - struct lovsub_lock *lsk; - int result; - - ENTRY; - OBD_SLAB_ALLOC_PTR_GFP(lsk, lovsub_lock_kmem, CFS_ALLOC_IO); - if (lsk != NULL) { - CFS_INIT_LIST_HEAD(&lsk->lss_parents); - cl_lock_slice_add(lock, &lsk->lss_cl, obj, &lovsub_lock_ops); - result = 0; - } else - result = -ENOMEM; - RETURN(result); + struct lovsub_lock *lsk; + int result; + + ENTRY; + OBD_SLAB_ALLOC_PTR_GFP(lsk, lovsub_lock_kmem, GFP_NOFS); + if (lsk != NULL) { + INIT_LIST_HEAD(&lsk->lss_parents); + cl_lock_slice_add(lock, &lsk->lss_cl, obj, &lovsub_lock_ops); + result = 0; + } else + result = -ENOMEM; + RETURN(result); } /** @} lov */