| 1 | /* |
| 2 | * GPL HEADER START |
| 3 | * |
| 4 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 only, |
| 8 | * as published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, but |
| 11 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 13 | * General Public License version 2 for more details (a copy is included |
| 14 | * in the LICENSE file that accompanied this code). |
| 15 | * |
| 16 | * You should have received a copy of the GNU General Public License |
| 17 | * version 2 along with this program; If not, see |
| 18 | * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf |
| 19 | * |
| 20 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 21 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 22 | * have any questions. |
| 23 | * |
| 24 | * GPL HEADER END |
| 25 | */ |
| 26 | /* |
| 27 | * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved. |
| 28 | * Use is subject to license terms. |
| 29 | * |
| 30 | * Copyright (c) 2011, 2012, Intel Corporation. |
| 31 | */ |
| 32 | /* |
| 33 | * This file is part of Lustre, http://www.lustre.org/ |
| 34 | * Lustre is a trademark of Sun Microsystems, Inc. |
| 35 | * |
| 36 | * Client Extent Lock. |
| 37 | * |
| 38 | * Author: Nikita Danilov <nikita.danilov@sun.com> |
| 39 | */ |
| 40 | |
| 41 | #define DEBUG_SUBSYSTEM S_CLASS |
| 42 | |
| 43 | #include "../include/obd_class.h" |
| 44 | #include "../include/obd_support.h" |
| 45 | #include "../include/lustre_fid.h" |
| 46 | #include <linux/list.h> |
| 47 | #include "../include/cl_object.h" |
| 48 | #include "cl_internal.h" |
| 49 | |
| 50 | /** Lock class of cl_lock::cll_guard */ |
| 51 | static struct lock_class_key cl_lock_guard_class; |
| 52 | static struct kmem_cache *cl_lock_kmem; |
| 53 | |
| 54 | static struct lu_kmem_descr cl_lock_caches[] = { |
| 55 | { |
| 56 | .ckd_cache = &cl_lock_kmem, |
| 57 | .ckd_name = "cl_lock_kmem", |
| 58 | .ckd_size = sizeof (struct cl_lock) |
| 59 | }, |
| 60 | { |
| 61 | .ckd_cache = NULL |
| 62 | } |
| 63 | }; |
| 64 | |
| 65 | #define CS_LOCK_INC(o, item) |
| 66 | #define CS_LOCK_DEC(o, item) |
| 67 | #define CS_LOCKSTATE_INC(o, state) |
| 68 | #define CS_LOCKSTATE_DEC(o, state) |
| 69 | |
| 70 | /** |
| 71 | * Basic lock invariant that is maintained at all times. Caller either has a |
| 72 | * reference to \a lock, or somehow assures that \a lock cannot be freed. |
| 73 | * |
| 74 | * \see cl_lock_invariant() |
| 75 | */ |
| 76 | static int cl_lock_invariant_trusted(const struct lu_env *env, |
| 77 | const struct cl_lock *lock) |
| 78 | { |
| 79 | return ergo(lock->cll_state == CLS_FREEING, lock->cll_holds == 0) && |
| 80 | atomic_read(&lock->cll_ref) >= lock->cll_holds && |
| 81 | lock->cll_holds >= lock->cll_users && |
| 82 | lock->cll_holds >= 0 && |
| 83 | lock->cll_users >= 0 && |
| 84 | lock->cll_depth >= 0; |
| 85 | } |
| 86 | |
| 87 | /** |
| 88 | * Stronger lock invariant, checking that caller has a reference on a lock. |
| 89 | * |
| 90 | * \see cl_lock_invariant_trusted() |
| 91 | */ |
| 92 | static int cl_lock_invariant(const struct lu_env *env, |
| 93 | const struct cl_lock *lock) |
| 94 | { |
| 95 | int result; |
| 96 | |
| 97 | result = atomic_read(&lock->cll_ref) > 0 && |
| 98 | cl_lock_invariant_trusted(env, lock); |
| 99 | if (!result && env != NULL) |
| 100 | CL_LOCK_DEBUG(D_ERROR, env, lock, "invariant broken"); |
| 101 | return result; |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Returns lock "nesting": 0 for a top-lock and 1 for a sub-lock. |
| 106 | */ |
| 107 | static enum clt_nesting_level cl_lock_nesting(const struct cl_lock *lock) |
| 108 | { |
| 109 | return cl_object_header(lock->cll_descr.cld_obj)->coh_nesting; |
| 110 | } |
| 111 | |
| 112 | /** |
| 113 | * Returns a set of counters for this lock, depending on a lock nesting. |
| 114 | */ |
| 115 | static struct cl_thread_counters *cl_lock_counters(const struct lu_env *env, |
| 116 | const struct cl_lock *lock) |
| 117 | { |
| 118 | struct cl_thread_info *info; |
| 119 | enum clt_nesting_level nesting; |
| 120 | |
| 121 | info = cl_env_info(env); |
| 122 | nesting = cl_lock_nesting(lock); |
| 123 | LASSERT(nesting < ARRAY_SIZE(info->clt_counters)); |
| 124 | return &info->clt_counters[nesting]; |
| 125 | } |
| 126 | |
| 127 | static void cl_lock_trace0(int level, const struct lu_env *env, |
| 128 | const char *prefix, const struct cl_lock *lock, |
| 129 | const char *func, const int line) |
| 130 | { |
| 131 | struct cl_object_header *h = cl_object_header(lock->cll_descr.cld_obj); |
| 132 | CDEBUG(level, "%s: %p@(%d %p %d %d %d %d %d %lx)(%p/%d/%d) at %s():%d\n", |
| 133 | prefix, lock, atomic_read(&lock->cll_ref), |
| 134 | lock->cll_guarder, lock->cll_depth, |
| 135 | lock->cll_state, lock->cll_error, lock->cll_holds, |
| 136 | lock->cll_users, lock->cll_flags, |
| 137 | env, h->coh_nesting, cl_lock_nr_mutexed(env), |
| 138 | func, line); |
| 139 | } |
| 140 | #define cl_lock_trace(level, env, prefix, lock) \ |
| 141 | cl_lock_trace0(level, env, prefix, lock, __func__, __LINE__) |
| 142 | |
| 143 | #define RETIP ((unsigned long)__builtin_return_address(0)) |
| 144 | |
| 145 | #ifdef CONFIG_LOCKDEP |
| 146 | static struct lock_class_key cl_lock_key; |
| 147 | |
| 148 | static void cl_lock_lockdep_init(struct cl_lock *lock) |
| 149 | { |
| 150 | lockdep_set_class_and_name(lock, &cl_lock_key, "EXT"); |
| 151 | } |
| 152 | |
| 153 | static void cl_lock_lockdep_acquire(const struct lu_env *env, |
| 154 | struct cl_lock *lock, __u32 enqflags) |
| 155 | { |
| 156 | cl_lock_counters(env, lock)->ctc_nr_locks_acquired++; |
| 157 | lock_map_acquire(&lock->dep_map); |
| 158 | } |
| 159 | |
| 160 | static void cl_lock_lockdep_release(const struct lu_env *env, |
| 161 | struct cl_lock *lock) |
| 162 | { |
| 163 | cl_lock_counters(env, lock)->ctc_nr_locks_acquired--; |
| 164 | lock_release(&lock->dep_map, 0, RETIP); |
| 165 | } |
| 166 | |
| 167 | #else /* !CONFIG_LOCKDEP */ |
| 168 | |
| 169 | static void cl_lock_lockdep_init(struct cl_lock *lock) |
| 170 | {} |
| 171 | static void cl_lock_lockdep_acquire(const struct lu_env *env, |
| 172 | struct cl_lock *lock, __u32 enqflags) |
| 173 | {} |
| 174 | static void cl_lock_lockdep_release(const struct lu_env *env, |
| 175 | struct cl_lock *lock) |
| 176 | {} |
| 177 | |
| 178 | #endif /* !CONFIG_LOCKDEP */ |
| 179 | |
| 180 | /** |
| 181 | * Adds lock slice to the compound lock. |
| 182 | * |
| 183 | * This is called by cl_object_operations::coo_lock_init() methods to add a |
| 184 | * per-layer state to the lock. New state is added at the end of |
| 185 | * cl_lock::cll_layers list, that is, it is at the bottom of the stack. |
| 186 | * |
| 187 | * \see cl_req_slice_add(), cl_page_slice_add(), cl_io_slice_add() |
| 188 | */ |
| 189 | void cl_lock_slice_add(struct cl_lock *lock, struct cl_lock_slice *slice, |
| 190 | struct cl_object *obj, |
| 191 | const struct cl_lock_operations *ops) |
| 192 | { |
| 193 | slice->cls_lock = lock; |
| 194 | list_add_tail(&slice->cls_linkage, &lock->cll_layers); |
| 195 | slice->cls_obj = obj; |
| 196 | slice->cls_ops = ops; |
| 197 | } |
| 198 | EXPORT_SYMBOL(cl_lock_slice_add); |
| 199 | |
| 200 | /** |
| 201 | * Returns true iff a lock with the mode \a has provides at least the same |
| 202 | * guarantees as a lock with the mode \a need. |
| 203 | */ |
| 204 | int cl_lock_mode_match(enum cl_lock_mode has, enum cl_lock_mode need) |
| 205 | { |
| 206 | LINVRNT(need == CLM_READ || need == CLM_WRITE || |
| 207 | need == CLM_PHANTOM || need == CLM_GROUP); |
| 208 | LINVRNT(has == CLM_READ || has == CLM_WRITE || |
| 209 | has == CLM_PHANTOM || has == CLM_GROUP); |
| 210 | CLASSERT(CLM_PHANTOM < CLM_READ); |
| 211 | CLASSERT(CLM_READ < CLM_WRITE); |
| 212 | CLASSERT(CLM_WRITE < CLM_GROUP); |
| 213 | |
| 214 | if (has != CLM_GROUP) |
| 215 | return need <= has; |
| 216 | else |
| 217 | return need == has; |
| 218 | } |
| 219 | EXPORT_SYMBOL(cl_lock_mode_match); |
| 220 | |
| 221 | /** |
| 222 | * Returns true iff extent portions of lock descriptions match. |
| 223 | */ |
| 224 | int cl_lock_ext_match(const struct cl_lock_descr *has, |
| 225 | const struct cl_lock_descr *need) |
| 226 | { |
| 227 | return |
| 228 | has->cld_start <= need->cld_start && |
| 229 | has->cld_end >= need->cld_end && |
| 230 | cl_lock_mode_match(has->cld_mode, need->cld_mode) && |
| 231 | (has->cld_mode != CLM_GROUP || has->cld_gid == need->cld_gid); |
| 232 | } |
| 233 | EXPORT_SYMBOL(cl_lock_ext_match); |
| 234 | |
| 235 | /** |
| 236 | * Returns true iff a lock with the description \a has provides at least the |
| 237 | * same guarantees as a lock with the description \a need. |
| 238 | */ |
| 239 | int cl_lock_descr_match(const struct cl_lock_descr *has, |
| 240 | const struct cl_lock_descr *need) |
| 241 | { |
| 242 | return |
| 243 | cl_object_same(has->cld_obj, need->cld_obj) && |
| 244 | cl_lock_ext_match(has, need); |
| 245 | } |
| 246 | EXPORT_SYMBOL(cl_lock_descr_match); |
| 247 | |
| 248 | static void cl_lock_free(const struct lu_env *env, struct cl_lock *lock) |
| 249 | { |
| 250 | struct cl_object *obj = lock->cll_descr.cld_obj; |
| 251 | |
| 252 | LINVRNT(!cl_lock_is_mutexed(lock)); |
| 253 | |
| 254 | cl_lock_trace(D_DLMTRACE, env, "free lock", lock); |
| 255 | might_sleep(); |
| 256 | while (!list_empty(&lock->cll_layers)) { |
| 257 | struct cl_lock_slice *slice; |
| 258 | |
| 259 | slice = list_entry(lock->cll_layers.next, |
| 260 | struct cl_lock_slice, cls_linkage); |
| 261 | list_del_init(lock->cll_layers.next); |
| 262 | slice->cls_ops->clo_fini(env, slice); |
| 263 | } |
| 264 | CS_LOCK_DEC(obj, total); |
| 265 | CS_LOCKSTATE_DEC(obj, lock->cll_state); |
| 266 | lu_object_ref_del_at(&obj->co_lu, &lock->cll_obj_ref, "cl_lock", lock); |
| 267 | cl_object_put(env, obj); |
| 268 | lu_ref_fini(&lock->cll_reference); |
| 269 | lu_ref_fini(&lock->cll_holders); |
| 270 | mutex_destroy(&lock->cll_guard); |
| 271 | OBD_SLAB_FREE_PTR(lock, cl_lock_kmem); |
| 272 | } |
| 273 | |
| 274 | /** |
| 275 | * Releases a reference on a lock. |
| 276 | * |
| 277 | * When last reference is released, lock is returned to the cache, unless it |
| 278 | * is in cl_lock_state::CLS_FREEING state, in which case it is destroyed |
| 279 | * immediately. |
| 280 | * |
| 281 | * \see cl_object_put(), cl_page_put() |
| 282 | */ |
| 283 | void cl_lock_put(const struct lu_env *env, struct cl_lock *lock) |
| 284 | { |
| 285 | struct cl_object *obj; |
| 286 | |
| 287 | LINVRNT(cl_lock_invariant(env, lock)); |
| 288 | obj = lock->cll_descr.cld_obj; |
| 289 | LINVRNT(obj != NULL); |
| 290 | |
| 291 | CDEBUG(D_TRACE, "releasing reference: %d %p %lu\n", |
| 292 | atomic_read(&lock->cll_ref), lock, RETIP); |
| 293 | |
| 294 | if (atomic_dec_and_test(&lock->cll_ref)) { |
| 295 | if (lock->cll_state == CLS_FREEING) { |
| 296 | LASSERT(list_empty(&lock->cll_linkage)); |
| 297 | cl_lock_free(env, lock); |
| 298 | } |
| 299 | CS_LOCK_DEC(obj, busy); |
| 300 | } |
| 301 | } |
| 302 | EXPORT_SYMBOL(cl_lock_put); |
| 303 | |
| 304 | /** |
| 305 | * Acquires an additional reference to a lock. |
| 306 | * |
| 307 | * This can be called only by caller already possessing a reference to \a |
| 308 | * lock. |
| 309 | * |
| 310 | * \see cl_object_get(), cl_page_get() |
| 311 | */ |
| 312 | void cl_lock_get(struct cl_lock *lock) |
| 313 | { |
| 314 | LINVRNT(cl_lock_invariant(NULL, lock)); |
| 315 | CDEBUG(D_TRACE, "acquiring reference: %d %p %lu\n", |
| 316 | atomic_read(&lock->cll_ref), lock, RETIP); |
| 317 | atomic_inc(&lock->cll_ref); |
| 318 | } |
| 319 | EXPORT_SYMBOL(cl_lock_get); |
| 320 | |
| 321 | /** |
| 322 | * Acquires a reference to a lock. |
| 323 | * |
| 324 | * This is much like cl_lock_get(), except that this function can be used to |
| 325 | * acquire initial reference to the cached lock. Caller has to deal with all |
| 326 | * possible races. Use with care! |
| 327 | * |
| 328 | * \see cl_page_get_trust() |
| 329 | */ |
| 330 | void cl_lock_get_trust(struct cl_lock *lock) |
| 331 | { |
| 332 | CDEBUG(D_TRACE, "acquiring trusted reference: %d %p %lu\n", |
| 333 | atomic_read(&lock->cll_ref), lock, RETIP); |
| 334 | if (atomic_inc_return(&lock->cll_ref) == 1) |
| 335 | CS_LOCK_INC(lock->cll_descr.cld_obj, busy); |
| 336 | } |
| 337 | EXPORT_SYMBOL(cl_lock_get_trust); |
| 338 | |
| 339 | /** |
| 340 | * Helper function destroying the lock that wasn't completely initialized. |
| 341 | * |
| 342 | * Other threads can acquire references to the top-lock through its |
| 343 | * sub-locks. Hence, it cannot be cl_lock_free()-ed immediately. |
| 344 | */ |
| 345 | static void cl_lock_finish(const struct lu_env *env, struct cl_lock *lock) |
| 346 | { |
| 347 | cl_lock_mutex_get(env, lock); |
| 348 | cl_lock_cancel(env, lock); |
| 349 | cl_lock_delete(env, lock); |
| 350 | cl_lock_mutex_put(env, lock); |
| 351 | cl_lock_put(env, lock); |
| 352 | } |
| 353 | |
| 354 | static struct cl_lock *cl_lock_alloc(const struct lu_env *env, |
| 355 | struct cl_object *obj, |
| 356 | const struct cl_io *io, |
| 357 | const struct cl_lock_descr *descr) |
| 358 | { |
| 359 | struct cl_lock *lock; |
| 360 | struct lu_object_header *head; |
| 361 | |
| 362 | OBD_SLAB_ALLOC_PTR_GFP(lock, cl_lock_kmem, GFP_NOFS); |
| 363 | if (lock != NULL) { |
| 364 | atomic_set(&lock->cll_ref, 1); |
| 365 | lock->cll_descr = *descr; |
| 366 | lock->cll_state = CLS_NEW; |
| 367 | cl_object_get(obj); |
| 368 | lu_object_ref_add_at(&obj->co_lu, &lock->cll_obj_ref, "cl_lock", |
| 369 | lock); |
| 370 | INIT_LIST_HEAD(&lock->cll_layers); |
| 371 | INIT_LIST_HEAD(&lock->cll_linkage); |
| 372 | INIT_LIST_HEAD(&lock->cll_inclosure); |
| 373 | lu_ref_init(&lock->cll_reference); |
| 374 | lu_ref_init(&lock->cll_holders); |
| 375 | mutex_init(&lock->cll_guard); |
| 376 | lockdep_set_class(&lock->cll_guard, &cl_lock_guard_class); |
| 377 | init_waitqueue_head(&lock->cll_wq); |
| 378 | head = obj->co_lu.lo_header; |
| 379 | CS_LOCKSTATE_INC(obj, CLS_NEW); |
| 380 | CS_LOCK_INC(obj, total); |
| 381 | CS_LOCK_INC(obj, create); |
| 382 | cl_lock_lockdep_init(lock); |
| 383 | list_for_each_entry(obj, &head->loh_layers, |
| 384 | co_lu.lo_linkage) { |
| 385 | int err; |
| 386 | |
| 387 | err = obj->co_ops->coo_lock_init(env, obj, lock, io); |
| 388 | if (err != 0) { |
| 389 | cl_lock_finish(env, lock); |
| 390 | lock = ERR_PTR(err); |
| 391 | break; |
| 392 | } |
| 393 | } |
| 394 | } else |
| 395 | lock = ERR_PTR(-ENOMEM); |
| 396 | return lock; |
| 397 | } |
| 398 | |
| 399 | /** |
| 400 | * Transfer the lock into INTRANSIT state and return the original state. |
| 401 | * |
| 402 | * \pre state: CLS_CACHED, CLS_HELD or CLS_ENQUEUED |
| 403 | * \post state: CLS_INTRANSIT |
| 404 | * \see CLS_INTRANSIT |
| 405 | */ |
| 406 | enum cl_lock_state cl_lock_intransit(const struct lu_env *env, |
| 407 | struct cl_lock *lock) |
| 408 | { |
| 409 | enum cl_lock_state state = lock->cll_state; |
| 410 | |
| 411 | LASSERT(cl_lock_is_mutexed(lock)); |
| 412 | LASSERT(state != CLS_INTRANSIT); |
| 413 | LASSERTF(state >= CLS_ENQUEUED && state <= CLS_CACHED, |
| 414 | "Malformed lock state %d.\n", state); |
| 415 | |
| 416 | cl_lock_state_set(env, lock, CLS_INTRANSIT); |
| 417 | lock->cll_intransit_owner = current; |
| 418 | cl_lock_hold_add(env, lock, "intransit", current); |
| 419 | return state; |
| 420 | } |
| 421 | EXPORT_SYMBOL(cl_lock_intransit); |
| 422 | |
| 423 | /** |
| 424 | * Exit the intransit state and restore the lock state to the original state |
| 425 | */ |
| 426 | void cl_lock_extransit(const struct lu_env *env, struct cl_lock *lock, |
| 427 | enum cl_lock_state state) |
| 428 | { |
| 429 | LASSERT(cl_lock_is_mutexed(lock)); |
| 430 | LASSERT(lock->cll_state == CLS_INTRANSIT); |
| 431 | LASSERT(state != CLS_INTRANSIT); |
| 432 | LASSERT(lock->cll_intransit_owner == current); |
| 433 | |
| 434 | lock->cll_intransit_owner = NULL; |
| 435 | cl_lock_state_set(env, lock, state); |
| 436 | cl_lock_unhold(env, lock, "intransit", current); |
| 437 | } |
| 438 | EXPORT_SYMBOL(cl_lock_extransit); |
| 439 | |
| 440 | /** |
| 441 | * Checking whether the lock is intransit state |
| 442 | */ |
| 443 | int cl_lock_is_intransit(struct cl_lock *lock) |
| 444 | { |
| 445 | LASSERT(cl_lock_is_mutexed(lock)); |
| 446 | return lock->cll_state == CLS_INTRANSIT && |
| 447 | lock->cll_intransit_owner != current; |
| 448 | } |
| 449 | EXPORT_SYMBOL(cl_lock_is_intransit); |
| 450 | /** |
| 451 | * Returns true iff lock is "suitable" for given io. E.g., locks acquired by |
| 452 | * truncate and O_APPEND cannot be reused for read/non-append-write, as they |
| 453 | * cover multiple stripes and can trigger cascading timeouts. |
| 454 | */ |
| 455 | static int cl_lock_fits_into(const struct lu_env *env, |
| 456 | const struct cl_lock *lock, |
| 457 | const struct cl_lock_descr *need, |
| 458 | const struct cl_io *io) |
| 459 | { |
| 460 | const struct cl_lock_slice *slice; |
| 461 | |
| 462 | LINVRNT(cl_lock_invariant_trusted(env, lock)); |
| 463 | list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { |
| 464 | if (slice->cls_ops->clo_fits_into != NULL && |
| 465 | !slice->cls_ops->clo_fits_into(env, slice, need, io)) |
| 466 | return 0; |
| 467 | } |
| 468 | return 1; |
| 469 | } |
| 470 | |
| 471 | static struct cl_lock *cl_lock_lookup(const struct lu_env *env, |
| 472 | struct cl_object *obj, |
| 473 | const struct cl_io *io, |
| 474 | const struct cl_lock_descr *need) |
| 475 | { |
| 476 | struct cl_lock *lock; |
| 477 | struct cl_object_header *head; |
| 478 | |
| 479 | head = cl_object_header(obj); |
| 480 | assert_spin_locked(&head->coh_lock_guard); |
| 481 | CS_LOCK_INC(obj, lookup); |
| 482 | list_for_each_entry(lock, &head->coh_locks, cll_linkage) { |
| 483 | int matched; |
| 484 | |
| 485 | matched = cl_lock_ext_match(&lock->cll_descr, need) && |
| 486 | lock->cll_state < CLS_FREEING && |
| 487 | lock->cll_error == 0 && |
| 488 | !(lock->cll_flags & CLF_CANCELLED) && |
| 489 | cl_lock_fits_into(env, lock, need, io); |
| 490 | CDEBUG(D_DLMTRACE, "has: "DDESCR"(%d) need: "DDESCR": %d\n", |
| 491 | PDESCR(&lock->cll_descr), lock->cll_state, PDESCR(need), |
| 492 | matched); |
| 493 | if (matched) { |
| 494 | cl_lock_get_trust(lock); |
| 495 | CS_LOCK_INC(obj, hit); |
| 496 | return lock; |
| 497 | } |
| 498 | } |
| 499 | return NULL; |
| 500 | } |
| 501 | |
| 502 | /** |
| 503 | * Returns a lock matching description \a need. |
| 504 | * |
| 505 | * This is the main entry point into the cl_lock caching interface. First, a |
| 506 | * cache (implemented as a per-object linked list) is consulted. If lock is |
| 507 | * found there, it is returned immediately. Otherwise new lock is allocated |
| 508 | * and returned. In any case, additional reference to lock is acquired. |
| 509 | * |
| 510 | * \see cl_object_find(), cl_page_find() |
| 511 | */ |
| 512 | static struct cl_lock *cl_lock_find(const struct lu_env *env, |
| 513 | const struct cl_io *io, |
| 514 | const struct cl_lock_descr *need) |
| 515 | { |
| 516 | struct cl_object_header *head; |
| 517 | struct cl_object *obj; |
| 518 | struct cl_lock *lock; |
| 519 | |
| 520 | obj = need->cld_obj; |
| 521 | head = cl_object_header(obj); |
| 522 | |
| 523 | spin_lock(&head->coh_lock_guard); |
| 524 | lock = cl_lock_lookup(env, obj, io, need); |
| 525 | spin_unlock(&head->coh_lock_guard); |
| 526 | |
| 527 | if (lock == NULL) { |
| 528 | lock = cl_lock_alloc(env, obj, io, need); |
| 529 | if (!IS_ERR(lock)) { |
| 530 | struct cl_lock *ghost; |
| 531 | |
| 532 | spin_lock(&head->coh_lock_guard); |
| 533 | ghost = cl_lock_lookup(env, obj, io, need); |
| 534 | if (ghost == NULL) { |
| 535 | cl_lock_get_trust(lock); |
| 536 | list_add_tail(&lock->cll_linkage, |
| 537 | &head->coh_locks); |
| 538 | spin_unlock(&head->coh_lock_guard); |
| 539 | CS_LOCK_INC(obj, busy); |
| 540 | } else { |
| 541 | spin_unlock(&head->coh_lock_guard); |
| 542 | /* |
| 543 | * Other threads can acquire references to the |
| 544 | * top-lock through its sub-locks. Hence, it |
| 545 | * cannot be cl_lock_free()-ed immediately. |
| 546 | */ |
| 547 | cl_lock_finish(env, lock); |
| 548 | lock = ghost; |
| 549 | } |
| 550 | } |
| 551 | } |
| 552 | return lock; |
| 553 | } |
| 554 | |
| 555 | /** |
| 556 | * Returns existing lock matching given description. This is similar to |
| 557 | * cl_lock_find() except that no new lock is created, and returned lock is |
| 558 | * guaranteed to be in enum cl_lock_state::CLS_HELD state. |
| 559 | */ |
| 560 | struct cl_lock *cl_lock_peek(const struct lu_env *env, const struct cl_io *io, |
| 561 | const struct cl_lock_descr *need, |
| 562 | const char *scope, const void *source) |
| 563 | { |
| 564 | struct cl_object_header *head; |
| 565 | struct cl_object *obj; |
| 566 | struct cl_lock *lock; |
| 567 | |
| 568 | obj = need->cld_obj; |
| 569 | head = cl_object_header(obj); |
| 570 | |
| 571 | do { |
| 572 | spin_lock(&head->coh_lock_guard); |
| 573 | lock = cl_lock_lookup(env, obj, io, need); |
| 574 | spin_unlock(&head->coh_lock_guard); |
| 575 | if (lock == NULL) |
| 576 | return NULL; |
| 577 | |
| 578 | cl_lock_mutex_get(env, lock); |
| 579 | if (lock->cll_state == CLS_INTRANSIT) |
| 580 | /* Don't care return value. */ |
| 581 | cl_lock_state_wait(env, lock); |
| 582 | if (lock->cll_state == CLS_FREEING) { |
| 583 | cl_lock_mutex_put(env, lock); |
| 584 | cl_lock_put(env, lock); |
| 585 | lock = NULL; |
| 586 | } |
| 587 | } while (lock == NULL); |
| 588 | |
| 589 | cl_lock_hold_add(env, lock, scope, source); |
| 590 | cl_lock_user_add(env, lock); |
| 591 | if (lock->cll_state == CLS_CACHED) |
| 592 | cl_use_try(env, lock, 1); |
| 593 | if (lock->cll_state == CLS_HELD) { |
| 594 | cl_lock_mutex_put(env, lock); |
| 595 | cl_lock_lockdep_acquire(env, lock, 0); |
| 596 | cl_lock_put(env, lock); |
| 597 | } else { |
| 598 | cl_unuse_try(env, lock); |
| 599 | cl_lock_unhold(env, lock, scope, source); |
| 600 | cl_lock_mutex_put(env, lock); |
| 601 | cl_lock_put(env, lock); |
| 602 | lock = NULL; |
| 603 | } |
| 604 | |
| 605 | return lock; |
| 606 | } |
| 607 | EXPORT_SYMBOL(cl_lock_peek); |
| 608 | |
| 609 | /** |
| 610 | * Returns a slice within a lock, corresponding to the given layer in the |
| 611 | * device stack. |
| 612 | * |
| 613 | * \see cl_page_at() |
| 614 | */ |
| 615 | const struct cl_lock_slice *cl_lock_at(const struct cl_lock *lock, |
| 616 | const struct lu_device_type *dtype) |
| 617 | { |
| 618 | const struct cl_lock_slice *slice; |
| 619 | |
| 620 | LINVRNT(cl_lock_invariant_trusted(NULL, lock)); |
| 621 | |
| 622 | list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { |
| 623 | if (slice->cls_obj->co_lu.lo_dev->ld_type == dtype) |
| 624 | return slice; |
| 625 | } |
| 626 | return NULL; |
| 627 | } |
| 628 | EXPORT_SYMBOL(cl_lock_at); |
| 629 | |
| 630 | static void cl_lock_mutex_tail(const struct lu_env *env, struct cl_lock *lock) |
| 631 | { |
| 632 | struct cl_thread_counters *counters; |
| 633 | |
| 634 | counters = cl_lock_counters(env, lock); |
| 635 | lock->cll_depth++; |
| 636 | counters->ctc_nr_locks_locked++; |
| 637 | lu_ref_add(&counters->ctc_locks_locked, "cll_guard", lock); |
| 638 | cl_lock_trace(D_TRACE, env, "got mutex", lock); |
| 639 | } |
| 640 | |
| 641 | /** |
| 642 | * Locks cl_lock object. |
| 643 | * |
| 644 | * This is used to manipulate cl_lock fields, and to serialize state |
| 645 | * transitions in the lock state machine. |
| 646 | * |
| 647 | * \post cl_lock_is_mutexed(lock) |
| 648 | * |
| 649 | * \see cl_lock_mutex_put() |
| 650 | */ |
| 651 | void cl_lock_mutex_get(const struct lu_env *env, struct cl_lock *lock) |
| 652 | { |
| 653 | LINVRNT(cl_lock_invariant(env, lock)); |
| 654 | |
| 655 | if (lock->cll_guarder == current) { |
| 656 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 657 | LINVRNT(lock->cll_depth > 0); |
| 658 | } else { |
| 659 | struct cl_object_header *hdr; |
| 660 | struct cl_thread_info *info; |
| 661 | int i; |
| 662 | |
| 663 | LINVRNT(lock->cll_guarder != current); |
| 664 | hdr = cl_object_header(lock->cll_descr.cld_obj); |
| 665 | /* |
| 666 | * Check that mutices are taken in the bottom-to-top order. |
| 667 | */ |
| 668 | info = cl_env_info(env); |
| 669 | for (i = 0; i < hdr->coh_nesting; ++i) |
| 670 | LASSERT(info->clt_counters[i].ctc_nr_locks_locked == 0); |
| 671 | mutex_lock_nested(&lock->cll_guard, hdr->coh_nesting); |
| 672 | lock->cll_guarder = current; |
| 673 | LINVRNT(lock->cll_depth == 0); |
| 674 | } |
| 675 | cl_lock_mutex_tail(env, lock); |
| 676 | } |
| 677 | EXPORT_SYMBOL(cl_lock_mutex_get); |
| 678 | |
| 679 | /** |
| 680 | * Try-locks cl_lock object. |
| 681 | * |
| 682 | * \retval 0 \a lock was successfully locked |
| 683 | * |
| 684 | * \retval -EBUSY \a lock cannot be locked right now |
| 685 | * |
| 686 | * \post ergo(result == 0, cl_lock_is_mutexed(lock)) |
| 687 | * |
| 688 | * \see cl_lock_mutex_get() |
| 689 | */ |
| 690 | int cl_lock_mutex_try(const struct lu_env *env, struct cl_lock *lock) |
| 691 | { |
| 692 | int result; |
| 693 | |
| 694 | LINVRNT(cl_lock_invariant_trusted(env, lock)); |
| 695 | |
| 696 | result = 0; |
| 697 | if (lock->cll_guarder == current) { |
| 698 | LINVRNT(lock->cll_depth > 0); |
| 699 | cl_lock_mutex_tail(env, lock); |
| 700 | } else if (mutex_trylock(&lock->cll_guard)) { |
| 701 | LINVRNT(lock->cll_depth == 0); |
| 702 | lock->cll_guarder = current; |
| 703 | cl_lock_mutex_tail(env, lock); |
| 704 | } else |
| 705 | result = -EBUSY; |
| 706 | return result; |
| 707 | } |
| 708 | EXPORT_SYMBOL(cl_lock_mutex_try); |
| 709 | |
| 710 | /** |
| 711 | {* Unlocks cl_lock object. |
| 712 | * |
| 713 | * \pre cl_lock_is_mutexed(lock) |
| 714 | * |
| 715 | * \see cl_lock_mutex_get() |
| 716 | */ |
| 717 | void cl_lock_mutex_put(const struct lu_env *env, struct cl_lock *lock) |
| 718 | { |
| 719 | struct cl_thread_counters *counters; |
| 720 | |
| 721 | LINVRNT(cl_lock_invariant(env, lock)); |
| 722 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 723 | LINVRNT(lock->cll_guarder == current); |
| 724 | LINVRNT(lock->cll_depth > 0); |
| 725 | |
| 726 | counters = cl_lock_counters(env, lock); |
| 727 | LINVRNT(counters->ctc_nr_locks_locked > 0); |
| 728 | |
| 729 | cl_lock_trace(D_TRACE, env, "put mutex", lock); |
| 730 | lu_ref_del(&counters->ctc_locks_locked, "cll_guard", lock); |
| 731 | counters->ctc_nr_locks_locked--; |
| 732 | if (--lock->cll_depth == 0) { |
| 733 | lock->cll_guarder = NULL; |
| 734 | mutex_unlock(&lock->cll_guard); |
| 735 | } |
| 736 | } |
| 737 | EXPORT_SYMBOL(cl_lock_mutex_put); |
| 738 | |
| 739 | /** |
| 740 | * Returns true iff lock's mutex is owned by the current thread. |
| 741 | */ |
| 742 | int cl_lock_is_mutexed(struct cl_lock *lock) |
| 743 | { |
| 744 | return lock->cll_guarder == current; |
| 745 | } |
| 746 | EXPORT_SYMBOL(cl_lock_is_mutexed); |
| 747 | |
| 748 | /** |
| 749 | * Returns number of cl_lock mutices held by the current thread (environment). |
| 750 | */ |
| 751 | int cl_lock_nr_mutexed(const struct lu_env *env) |
| 752 | { |
| 753 | struct cl_thread_info *info; |
| 754 | int i; |
| 755 | int locked; |
| 756 | |
| 757 | /* |
| 758 | * NOTE: if summation across all nesting levels (currently 2) proves |
| 759 | * too expensive, a summary counter can be added to |
| 760 | * struct cl_thread_info. |
| 761 | */ |
| 762 | info = cl_env_info(env); |
| 763 | for (i = 0, locked = 0; i < ARRAY_SIZE(info->clt_counters); ++i) |
| 764 | locked += info->clt_counters[i].ctc_nr_locks_locked; |
| 765 | return locked; |
| 766 | } |
| 767 | EXPORT_SYMBOL(cl_lock_nr_mutexed); |
| 768 | |
| 769 | static void cl_lock_cancel0(const struct lu_env *env, struct cl_lock *lock) |
| 770 | { |
| 771 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 772 | LINVRNT(cl_lock_invariant(env, lock)); |
| 773 | if (!(lock->cll_flags & CLF_CANCELLED)) { |
| 774 | const struct cl_lock_slice *slice; |
| 775 | |
| 776 | lock->cll_flags |= CLF_CANCELLED; |
| 777 | list_for_each_entry_reverse(slice, &lock->cll_layers, |
| 778 | cls_linkage) { |
| 779 | if (slice->cls_ops->clo_cancel != NULL) |
| 780 | slice->cls_ops->clo_cancel(env, slice); |
| 781 | } |
| 782 | } |
| 783 | } |
| 784 | |
| 785 | static void cl_lock_delete0(const struct lu_env *env, struct cl_lock *lock) |
| 786 | { |
| 787 | struct cl_object_header *head; |
| 788 | const struct cl_lock_slice *slice; |
| 789 | |
| 790 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 791 | LINVRNT(cl_lock_invariant(env, lock)); |
| 792 | |
| 793 | if (lock->cll_state < CLS_FREEING) { |
| 794 | bool in_cache; |
| 795 | |
| 796 | LASSERT(lock->cll_state != CLS_INTRANSIT); |
| 797 | cl_lock_state_set(env, lock, CLS_FREEING); |
| 798 | |
| 799 | head = cl_object_header(lock->cll_descr.cld_obj); |
| 800 | |
| 801 | spin_lock(&head->coh_lock_guard); |
| 802 | in_cache = !list_empty(&lock->cll_linkage); |
| 803 | if (in_cache) |
| 804 | list_del_init(&lock->cll_linkage); |
| 805 | spin_unlock(&head->coh_lock_guard); |
| 806 | |
| 807 | if (in_cache) /* coh_locks cache holds a refcount. */ |
| 808 | cl_lock_put(env, lock); |
| 809 | |
| 810 | /* |
| 811 | * From now on, no new references to this lock can be acquired |
| 812 | * by cl_lock_lookup(). |
| 813 | */ |
| 814 | list_for_each_entry_reverse(slice, &lock->cll_layers, |
| 815 | cls_linkage) { |
| 816 | if (slice->cls_ops->clo_delete != NULL) |
| 817 | slice->cls_ops->clo_delete(env, slice); |
| 818 | } |
| 819 | /* |
| 820 | * From now on, no new references to this lock can be acquired |
| 821 | * by layer-specific means (like a pointer from struct |
| 822 | * ldlm_lock in osc, or a pointer from top-lock to sub-lock in |
| 823 | * lov). |
| 824 | * |
| 825 | * Lock will be finally freed in cl_lock_put() when last of |
| 826 | * existing references goes away. |
| 827 | */ |
| 828 | } |
| 829 | } |
| 830 | |
| 831 | /** |
| 832 | * Mod(ifie)s cl_lock::cll_holds counter for a given lock. Also, for a |
| 833 | * top-lock (nesting == 0) accounts for this modification in the per-thread |
| 834 | * debugging counters. Sub-lock holds can be released by a thread different |
| 835 | * from one that acquired it. |
| 836 | */ |
| 837 | static void cl_lock_hold_mod(const struct lu_env *env, struct cl_lock *lock, |
| 838 | int delta) |
| 839 | { |
| 840 | struct cl_thread_counters *counters; |
| 841 | enum clt_nesting_level nesting; |
| 842 | |
| 843 | lock->cll_holds += delta; |
| 844 | nesting = cl_lock_nesting(lock); |
| 845 | if (nesting == CNL_TOP) { |
| 846 | counters = &cl_env_info(env)->clt_counters[CNL_TOP]; |
| 847 | counters->ctc_nr_held += delta; |
| 848 | LASSERT(counters->ctc_nr_held >= 0); |
| 849 | } |
| 850 | } |
| 851 | |
| 852 | /** |
| 853 | * Mod(ifie)s cl_lock::cll_users counter for a given lock. See |
| 854 | * cl_lock_hold_mod() for the explanation of the debugging code. |
| 855 | */ |
| 856 | static void cl_lock_used_mod(const struct lu_env *env, struct cl_lock *lock, |
| 857 | int delta) |
| 858 | { |
| 859 | struct cl_thread_counters *counters; |
| 860 | enum clt_nesting_level nesting; |
| 861 | |
| 862 | lock->cll_users += delta; |
| 863 | nesting = cl_lock_nesting(lock); |
| 864 | if (nesting == CNL_TOP) { |
| 865 | counters = &cl_env_info(env)->clt_counters[CNL_TOP]; |
| 866 | counters->ctc_nr_used += delta; |
| 867 | LASSERT(counters->ctc_nr_used >= 0); |
| 868 | } |
| 869 | } |
| 870 | |
| 871 | void cl_lock_hold_release(const struct lu_env *env, struct cl_lock *lock, |
| 872 | const char *scope, const void *source) |
| 873 | { |
| 874 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 875 | LINVRNT(cl_lock_invariant(env, lock)); |
| 876 | LASSERT(lock->cll_holds > 0); |
| 877 | |
| 878 | cl_lock_trace(D_DLMTRACE, env, "hold release lock", lock); |
| 879 | lu_ref_del(&lock->cll_holders, scope, source); |
| 880 | cl_lock_hold_mod(env, lock, -1); |
| 881 | if (lock->cll_holds == 0) { |
| 882 | CL_LOCK_ASSERT(lock->cll_state != CLS_HELD, env, lock); |
| 883 | if (lock->cll_descr.cld_mode == CLM_PHANTOM || |
| 884 | lock->cll_descr.cld_mode == CLM_GROUP || |
| 885 | lock->cll_state != CLS_CACHED) |
| 886 | /* |
| 887 | * If lock is still phantom or grouplock when user is |
| 888 | * done with it---destroy the lock. |
| 889 | */ |
| 890 | lock->cll_flags |= CLF_CANCELPEND|CLF_DOOMED; |
| 891 | if (lock->cll_flags & CLF_CANCELPEND) { |
| 892 | lock->cll_flags &= ~CLF_CANCELPEND; |
| 893 | cl_lock_cancel0(env, lock); |
| 894 | } |
| 895 | if (lock->cll_flags & CLF_DOOMED) { |
| 896 | /* no longer doomed: it's dead... Jim. */ |
| 897 | lock->cll_flags &= ~CLF_DOOMED; |
| 898 | cl_lock_delete0(env, lock); |
| 899 | } |
| 900 | } |
| 901 | } |
| 902 | EXPORT_SYMBOL(cl_lock_hold_release); |
| 903 | |
| 904 | /** |
| 905 | * Waits until lock state is changed. |
| 906 | * |
| 907 | * This function is called with cl_lock mutex locked, atomically releases |
| 908 | * mutex and goes to sleep, waiting for a lock state change (signaled by |
| 909 | * cl_lock_signal()), and re-acquires the mutex before return. |
| 910 | * |
| 911 | * This function is used to wait until lock state machine makes some progress |
| 912 | * and to emulate synchronous operations on top of asynchronous lock |
| 913 | * interface. |
| 914 | * |
| 915 | * \retval -EINTR wait was interrupted |
| 916 | * |
| 917 | * \retval 0 wait wasn't interrupted |
| 918 | * |
| 919 | * \pre cl_lock_is_mutexed(lock) |
| 920 | * |
| 921 | * \see cl_lock_signal() |
| 922 | */ |
| 923 | int cl_lock_state_wait(const struct lu_env *env, struct cl_lock *lock) |
| 924 | { |
| 925 | wait_queue_t waiter; |
| 926 | sigset_t blocked; |
| 927 | int result; |
| 928 | |
| 929 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 930 | LINVRNT(cl_lock_invariant(env, lock)); |
| 931 | LASSERT(lock->cll_depth == 1); |
| 932 | LASSERT(lock->cll_state != CLS_FREEING); /* too late to wait */ |
| 933 | |
| 934 | cl_lock_trace(D_DLMTRACE, env, "state wait lock", lock); |
| 935 | result = lock->cll_error; |
| 936 | if (result == 0) { |
| 937 | /* To avoid being interrupted by the 'non-fatal' signals |
| 938 | * (SIGCHLD, for instance), we'd block them temporarily. |
| 939 | * LU-305 */ |
| 940 | blocked = cfs_block_sigsinv(LUSTRE_FATAL_SIGS); |
| 941 | |
| 942 | init_waitqueue_entry(&waiter, current); |
| 943 | add_wait_queue(&lock->cll_wq, &waiter); |
| 944 | set_current_state(TASK_INTERRUPTIBLE); |
| 945 | cl_lock_mutex_put(env, lock); |
| 946 | |
| 947 | LASSERT(cl_lock_nr_mutexed(env) == 0); |
| 948 | |
| 949 | /* Returning ERESTARTSYS instead of EINTR so syscalls |
| 950 | * can be restarted if signals are pending here */ |
| 951 | result = -ERESTARTSYS; |
| 952 | if (likely(!OBD_FAIL_CHECK(OBD_FAIL_LOCK_STATE_WAIT_INTR))) { |
| 953 | schedule(); |
| 954 | if (!cfs_signal_pending()) |
| 955 | result = 0; |
| 956 | } |
| 957 | |
| 958 | cl_lock_mutex_get(env, lock); |
| 959 | set_current_state(TASK_RUNNING); |
| 960 | remove_wait_queue(&lock->cll_wq, &waiter); |
| 961 | |
| 962 | /* Restore old blocked signals */ |
| 963 | cfs_restore_sigs(blocked); |
| 964 | } |
| 965 | return result; |
| 966 | } |
| 967 | EXPORT_SYMBOL(cl_lock_state_wait); |
| 968 | |
| 969 | static void cl_lock_state_signal(const struct lu_env *env, struct cl_lock *lock, |
| 970 | enum cl_lock_state state) |
| 971 | { |
| 972 | const struct cl_lock_slice *slice; |
| 973 | |
| 974 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 975 | LINVRNT(cl_lock_invariant(env, lock)); |
| 976 | |
| 977 | list_for_each_entry(slice, &lock->cll_layers, cls_linkage) |
| 978 | if (slice->cls_ops->clo_state != NULL) |
| 979 | slice->cls_ops->clo_state(env, slice, state); |
| 980 | wake_up_all(&lock->cll_wq); |
| 981 | } |
| 982 | |
| 983 | /** |
| 984 | * Notifies waiters that lock state changed. |
| 985 | * |
| 986 | * Wakes up all waiters sleeping in cl_lock_state_wait(), also notifies all |
| 987 | * layers about state change by calling cl_lock_operations::clo_state() |
| 988 | * top-to-bottom. |
| 989 | */ |
| 990 | void cl_lock_signal(const struct lu_env *env, struct cl_lock *lock) |
| 991 | { |
| 992 | cl_lock_trace(D_DLMTRACE, env, "state signal lock", lock); |
| 993 | cl_lock_state_signal(env, lock, lock->cll_state); |
| 994 | } |
| 995 | EXPORT_SYMBOL(cl_lock_signal); |
| 996 | |
| 997 | /** |
| 998 | * Changes lock state. |
| 999 | * |
| 1000 | * This function is invoked to notify layers that lock state changed, possible |
| 1001 | * as a result of an asynchronous event such as call-back reception. |
| 1002 | * |
| 1003 | * \post lock->cll_state == state |
| 1004 | * |
| 1005 | * \see cl_lock_operations::clo_state() |
| 1006 | */ |
| 1007 | void cl_lock_state_set(const struct lu_env *env, struct cl_lock *lock, |
| 1008 | enum cl_lock_state state) |
| 1009 | { |
| 1010 | LASSERT(lock->cll_state <= state || |
| 1011 | (lock->cll_state == CLS_CACHED && |
| 1012 | (state == CLS_HELD || /* lock found in cache */ |
| 1013 | state == CLS_NEW || /* sub-lock canceled */ |
| 1014 | state == CLS_INTRANSIT)) || |
| 1015 | /* lock is in transit state */ |
| 1016 | lock->cll_state == CLS_INTRANSIT); |
| 1017 | |
| 1018 | if (lock->cll_state != state) { |
| 1019 | CS_LOCKSTATE_DEC(lock->cll_descr.cld_obj, lock->cll_state); |
| 1020 | CS_LOCKSTATE_INC(lock->cll_descr.cld_obj, state); |
| 1021 | |
| 1022 | cl_lock_state_signal(env, lock, state); |
| 1023 | lock->cll_state = state; |
| 1024 | } |
| 1025 | } |
| 1026 | EXPORT_SYMBOL(cl_lock_state_set); |
| 1027 | |
| 1028 | static int cl_unuse_try_internal(const struct lu_env *env, struct cl_lock *lock) |
| 1029 | { |
| 1030 | const struct cl_lock_slice *slice; |
| 1031 | int result; |
| 1032 | |
| 1033 | do { |
| 1034 | result = 0; |
| 1035 | |
| 1036 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 1037 | LINVRNT(cl_lock_invariant(env, lock)); |
| 1038 | LASSERT(lock->cll_state == CLS_INTRANSIT); |
| 1039 | |
| 1040 | result = -ENOSYS; |
| 1041 | list_for_each_entry_reverse(slice, &lock->cll_layers, |
| 1042 | cls_linkage) { |
| 1043 | if (slice->cls_ops->clo_unuse != NULL) { |
| 1044 | result = slice->cls_ops->clo_unuse(env, slice); |
| 1045 | if (result != 0) |
| 1046 | break; |
| 1047 | } |
| 1048 | } |
| 1049 | LASSERT(result != -ENOSYS); |
| 1050 | } while (result == CLO_REPEAT); |
| 1051 | |
| 1052 | return result; |
| 1053 | } |
| 1054 | |
| 1055 | /** |
| 1056 | * Yanks lock from the cache (cl_lock_state::CLS_CACHED state) by calling |
| 1057 | * cl_lock_operations::clo_use() top-to-bottom to notify layers. |
| 1058 | * @atomic = 1, it must unuse the lock to recovery the lock to keep the |
| 1059 | * use process atomic |
| 1060 | */ |
| 1061 | int cl_use_try(const struct lu_env *env, struct cl_lock *lock, int atomic) |
| 1062 | { |
| 1063 | const struct cl_lock_slice *slice; |
| 1064 | int result; |
| 1065 | enum cl_lock_state state; |
| 1066 | |
| 1067 | cl_lock_trace(D_DLMTRACE, env, "use lock", lock); |
| 1068 | |
| 1069 | LASSERT(lock->cll_state == CLS_CACHED); |
| 1070 | if (lock->cll_error) |
| 1071 | return lock->cll_error; |
| 1072 | |
| 1073 | result = -ENOSYS; |
| 1074 | state = cl_lock_intransit(env, lock); |
| 1075 | list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { |
| 1076 | if (slice->cls_ops->clo_use != NULL) { |
| 1077 | result = slice->cls_ops->clo_use(env, slice); |
| 1078 | if (result != 0) |
| 1079 | break; |
| 1080 | } |
| 1081 | } |
| 1082 | LASSERT(result != -ENOSYS); |
| 1083 | |
| 1084 | LASSERTF(lock->cll_state == CLS_INTRANSIT, "Wrong state %d.\n", |
| 1085 | lock->cll_state); |
| 1086 | |
| 1087 | if (result == 0) { |
| 1088 | state = CLS_HELD; |
| 1089 | } else { |
| 1090 | if (result == -ESTALE) { |
| 1091 | /* |
| 1092 | * ESTALE means sublock being cancelled |
| 1093 | * at this time, and set lock state to |
| 1094 | * be NEW here and ask the caller to repeat. |
| 1095 | */ |
| 1096 | state = CLS_NEW; |
| 1097 | result = CLO_REPEAT; |
| 1098 | } |
| 1099 | |
| 1100 | /* @atomic means back-off-on-failure. */ |
| 1101 | if (atomic) { |
| 1102 | int rc; |
| 1103 | rc = cl_unuse_try_internal(env, lock); |
| 1104 | /* Vet the results. */ |
| 1105 | if (rc < 0 && result > 0) |
| 1106 | result = rc; |
| 1107 | } |
| 1108 | |
| 1109 | } |
| 1110 | cl_lock_extransit(env, lock, state); |
| 1111 | return result; |
| 1112 | } |
| 1113 | EXPORT_SYMBOL(cl_use_try); |
| 1114 | |
| 1115 | /** |
| 1116 | * Helper for cl_enqueue_try() that calls ->clo_enqueue() across all layers |
| 1117 | * top-to-bottom. |
| 1118 | */ |
| 1119 | static int cl_enqueue_kick(const struct lu_env *env, |
| 1120 | struct cl_lock *lock, |
| 1121 | struct cl_io *io, __u32 flags) |
| 1122 | { |
| 1123 | int result; |
| 1124 | const struct cl_lock_slice *slice; |
| 1125 | |
| 1126 | result = -ENOSYS; |
| 1127 | list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { |
| 1128 | if (slice->cls_ops->clo_enqueue != NULL) { |
| 1129 | result = slice->cls_ops->clo_enqueue(env, |
| 1130 | slice, io, flags); |
| 1131 | if (result != 0) |
| 1132 | break; |
| 1133 | } |
| 1134 | } |
| 1135 | LASSERT(result != -ENOSYS); |
| 1136 | return result; |
| 1137 | } |
| 1138 | |
| 1139 | /** |
| 1140 | * Tries to enqueue a lock. |
| 1141 | * |
| 1142 | * This function is called repeatedly by cl_enqueue() until either lock is |
| 1143 | * enqueued, or error occurs. This function does not block waiting for |
| 1144 | * networking communication to complete. |
| 1145 | * |
| 1146 | * \post ergo(result == 0, lock->cll_state == CLS_ENQUEUED || |
| 1147 | * lock->cll_state == CLS_HELD) |
| 1148 | * |
| 1149 | * \see cl_enqueue() cl_lock_operations::clo_enqueue() |
| 1150 | * \see cl_lock_state::CLS_ENQUEUED |
| 1151 | */ |
| 1152 | int cl_enqueue_try(const struct lu_env *env, struct cl_lock *lock, |
| 1153 | struct cl_io *io, __u32 flags) |
| 1154 | { |
| 1155 | int result; |
| 1156 | |
| 1157 | cl_lock_trace(D_DLMTRACE, env, "enqueue lock", lock); |
| 1158 | do { |
| 1159 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 1160 | |
| 1161 | result = lock->cll_error; |
| 1162 | if (result != 0) |
| 1163 | break; |
| 1164 | |
| 1165 | switch (lock->cll_state) { |
| 1166 | case CLS_NEW: |
| 1167 | cl_lock_state_set(env, lock, CLS_QUEUING); |
| 1168 | /* fall-through */ |
| 1169 | case CLS_QUEUING: |
| 1170 | /* kick layers. */ |
| 1171 | result = cl_enqueue_kick(env, lock, io, flags); |
| 1172 | /* For AGL case, the cl_lock::cll_state may |
| 1173 | * become CLS_HELD already. */ |
| 1174 | if (result == 0 && lock->cll_state == CLS_QUEUING) |
| 1175 | cl_lock_state_set(env, lock, CLS_ENQUEUED); |
| 1176 | break; |
| 1177 | case CLS_INTRANSIT: |
| 1178 | LASSERT(cl_lock_is_intransit(lock)); |
| 1179 | result = CLO_WAIT; |
| 1180 | break; |
| 1181 | case CLS_CACHED: |
| 1182 | /* yank lock from the cache. */ |
| 1183 | result = cl_use_try(env, lock, 0); |
| 1184 | break; |
| 1185 | case CLS_ENQUEUED: |
| 1186 | case CLS_HELD: |
| 1187 | result = 0; |
| 1188 | break; |
| 1189 | default: |
| 1190 | case CLS_FREEING: |
| 1191 | /* |
| 1192 | * impossible, only held locks with increased |
| 1193 | * ->cll_holds can be enqueued, and they cannot be |
| 1194 | * freed. |
| 1195 | */ |
| 1196 | LBUG(); |
| 1197 | } |
| 1198 | } while (result == CLO_REPEAT); |
| 1199 | return result; |
| 1200 | } |
| 1201 | EXPORT_SYMBOL(cl_enqueue_try); |
| 1202 | |
| 1203 | /** |
| 1204 | * Cancel the conflicting lock found during previous enqueue. |
| 1205 | * |
| 1206 | * \retval 0 conflicting lock has been canceled. |
| 1207 | * \retval -ve error code. |
| 1208 | */ |
| 1209 | int cl_lock_enqueue_wait(const struct lu_env *env, |
| 1210 | struct cl_lock *lock, |
| 1211 | int keep_mutex) |
| 1212 | { |
| 1213 | struct cl_lock *conflict; |
| 1214 | int rc = 0; |
| 1215 | |
| 1216 | LASSERT(cl_lock_is_mutexed(lock)); |
| 1217 | LASSERT(lock->cll_state == CLS_QUEUING); |
| 1218 | LASSERT(lock->cll_conflict != NULL); |
| 1219 | |
| 1220 | conflict = lock->cll_conflict; |
| 1221 | lock->cll_conflict = NULL; |
| 1222 | |
| 1223 | cl_lock_mutex_put(env, lock); |
| 1224 | LASSERT(cl_lock_nr_mutexed(env) == 0); |
| 1225 | |
| 1226 | cl_lock_mutex_get(env, conflict); |
| 1227 | cl_lock_trace(D_DLMTRACE, env, "enqueue wait", conflict); |
| 1228 | cl_lock_cancel(env, conflict); |
| 1229 | cl_lock_delete(env, conflict); |
| 1230 | |
| 1231 | while (conflict->cll_state != CLS_FREEING) { |
| 1232 | rc = cl_lock_state_wait(env, conflict); |
| 1233 | if (rc != 0) |
| 1234 | break; |
| 1235 | } |
| 1236 | cl_lock_mutex_put(env, conflict); |
| 1237 | lu_ref_del(&conflict->cll_reference, "cancel-wait", lock); |
| 1238 | cl_lock_put(env, conflict); |
| 1239 | |
| 1240 | if (keep_mutex) |
| 1241 | cl_lock_mutex_get(env, lock); |
| 1242 | |
| 1243 | LASSERT(rc <= 0); |
| 1244 | return rc; |
| 1245 | } |
| 1246 | EXPORT_SYMBOL(cl_lock_enqueue_wait); |
| 1247 | |
| 1248 | static int cl_enqueue_locked(const struct lu_env *env, struct cl_lock *lock, |
| 1249 | struct cl_io *io, __u32 enqflags) |
| 1250 | { |
| 1251 | int result; |
| 1252 | |
| 1253 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 1254 | LINVRNT(cl_lock_invariant(env, lock)); |
| 1255 | LASSERT(lock->cll_holds > 0); |
| 1256 | |
| 1257 | cl_lock_user_add(env, lock); |
| 1258 | do { |
| 1259 | result = cl_enqueue_try(env, lock, io, enqflags); |
| 1260 | if (result == CLO_WAIT) { |
| 1261 | if (lock->cll_conflict != NULL) |
| 1262 | result = cl_lock_enqueue_wait(env, lock, 1); |
| 1263 | else |
| 1264 | result = cl_lock_state_wait(env, lock); |
| 1265 | if (result == 0) |
| 1266 | continue; |
| 1267 | } |
| 1268 | break; |
| 1269 | } while (1); |
| 1270 | if (result != 0) |
| 1271 | cl_unuse_try(env, lock); |
| 1272 | LASSERT(ergo(result == 0 && !(enqflags & CEF_AGL), |
| 1273 | lock->cll_state == CLS_ENQUEUED || |
| 1274 | lock->cll_state == CLS_HELD)); |
| 1275 | return result; |
| 1276 | } |
| 1277 | |
| 1278 | /** |
| 1279 | * Enqueues a lock. |
| 1280 | * |
| 1281 | * \pre current thread or io owns a hold on lock. |
| 1282 | * |
| 1283 | * \post ergo(result == 0, lock->users increased) |
| 1284 | * \post ergo(result == 0, lock->cll_state == CLS_ENQUEUED || |
| 1285 | * lock->cll_state == CLS_HELD) |
| 1286 | */ |
| 1287 | int cl_enqueue(const struct lu_env *env, struct cl_lock *lock, |
| 1288 | struct cl_io *io, __u32 enqflags) |
| 1289 | { |
| 1290 | int result; |
| 1291 | |
| 1292 | cl_lock_lockdep_acquire(env, lock, enqflags); |
| 1293 | cl_lock_mutex_get(env, lock); |
| 1294 | result = cl_enqueue_locked(env, lock, io, enqflags); |
| 1295 | cl_lock_mutex_put(env, lock); |
| 1296 | if (result != 0) |
| 1297 | cl_lock_lockdep_release(env, lock); |
| 1298 | LASSERT(ergo(result == 0, lock->cll_state == CLS_ENQUEUED || |
| 1299 | lock->cll_state == CLS_HELD)); |
| 1300 | return result; |
| 1301 | } |
| 1302 | EXPORT_SYMBOL(cl_enqueue); |
| 1303 | |
| 1304 | /** |
| 1305 | * Tries to unlock a lock. |
| 1306 | * |
| 1307 | * This function is called to release underlying resource: |
| 1308 | * 1. for top lock, the resource is sublocks it held; |
| 1309 | * 2. for sublock, the resource is the reference to dlmlock. |
| 1310 | * |
| 1311 | * cl_unuse_try is a one-shot operation, so it must NOT return CLO_WAIT. |
| 1312 | * |
| 1313 | * \see cl_unuse() cl_lock_operations::clo_unuse() |
| 1314 | * \see cl_lock_state::CLS_CACHED |
| 1315 | */ |
| 1316 | int cl_unuse_try(const struct lu_env *env, struct cl_lock *lock) |
| 1317 | { |
| 1318 | int result; |
| 1319 | enum cl_lock_state state = CLS_NEW; |
| 1320 | |
| 1321 | cl_lock_trace(D_DLMTRACE, env, "unuse lock", lock); |
| 1322 | |
| 1323 | if (lock->cll_users > 1) { |
| 1324 | cl_lock_user_del(env, lock); |
| 1325 | return 0; |
| 1326 | } |
| 1327 | |
| 1328 | /* Only if the lock is in CLS_HELD or CLS_ENQUEUED state, it can hold |
| 1329 | * underlying resources. */ |
| 1330 | if (!(lock->cll_state == CLS_HELD || lock->cll_state == CLS_ENQUEUED)) { |
| 1331 | cl_lock_user_del(env, lock); |
| 1332 | return 0; |
| 1333 | } |
| 1334 | |
| 1335 | /* |
| 1336 | * New lock users (->cll_users) are not protecting unlocking |
| 1337 | * from proceeding. From this point, lock eventually reaches |
| 1338 | * CLS_CACHED, is reinitialized to CLS_NEW or fails into |
| 1339 | * CLS_FREEING. |
| 1340 | */ |
| 1341 | state = cl_lock_intransit(env, lock); |
| 1342 | |
| 1343 | result = cl_unuse_try_internal(env, lock); |
| 1344 | LASSERT(lock->cll_state == CLS_INTRANSIT); |
| 1345 | LASSERT(result != CLO_WAIT); |
| 1346 | cl_lock_user_del(env, lock); |
| 1347 | if (result == 0 || result == -ESTALE) { |
| 1348 | /* |
| 1349 | * Return lock back to the cache. This is the only |
| 1350 | * place where lock is moved into CLS_CACHED state. |
| 1351 | * |
| 1352 | * If one of ->clo_unuse() methods returned -ESTALE, lock |
| 1353 | * cannot be placed into cache and has to be |
| 1354 | * re-initialized. This happens e.g., when a sub-lock was |
| 1355 | * canceled while unlocking was in progress. |
| 1356 | */ |
| 1357 | if (state == CLS_HELD && result == 0) |
| 1358 | state = CLS_CACHED; |
| 1359 | else |
| 1360 | state = CLS_NEW; |
| 1361 | cl_lock_extransit(env, lock, state); |
| 1362 | |
| 1363 | /* |
| 1364 | * Hide -ESTALE error. |
| 1365 | * If the lock is a glimpse lock, and it has multiple |
| 1366 | * stripes. Assuming that one of its sublock returned -ENAVAIL, |
| 1367 | * and other sublocks are matched write locks. In this case, |
| 1368 | * we can't set this lock to error because otherwise some of |
| 1369 | * its sublocks may not be canceled. This causes some dirty |
| 1370 | * pages won't be written to OSTs. -jay |
| 1371 | */ |
| 1372 | result = 0; |
| 1373 | } else { |
| 1374 | CERROR("result = %d, this is unlikely!\n", result); |
| 1375 | state = CLS_NEW; |
| 1376 | cl_lock_extransit(env, lock, state); |
| 1377 | } |
| 1378 | return result ?: lock->cll_error; |
| 1379 | } |
| 1380 | EXPORT_SYMBOL(cl_unuse_try); |
| 1381 | |
| 1382 | static void cl_unuse_locked(const struct lu_env *env, struct cl_lock *lock) |
| 1383 | { |
| 1384 | int result; |
| 1385 | |
| 1386 | result = cl_unuse_try(env, lock); |
| 1387 | if (result) |
| 1388 | CL_LOCK_DEBUG(D_ERROR, env, lock, "unuse return %d\n", result); |
| 1389 | } |
| 1390 | |
| 1391 | /** |
| 1392 | * Unlocks a lock. |
| 1393 | */ |
| 1394 | void cl_unuse(const struct lu_env *env, struct cl_lock *lock) |
| 1395 | { |
| 1396 | cl_lock_mutex_get(env, lock); |
| 1397 | cl_unuse_locked(env, lock); |
| 1398 | cl_lock_mutex_put(env, lock); |
| 1399 | cl_lock_lockdep_release(env, lock); |
| 1400 | } |
| 1401 | EXPORT_SYMBOL(cl_unuse); |
| 1402 | |
| 1403 | /** |
| 1404 | * Tries to wait for a lock. |
| 1405 | * |
| 1406 | * This function is called repeatedly by cl_wait() until either lock is |
| 1407 | * granted, or error occurs. This function does not block waiting for network |
| 1408 | * communication to complete. |
| 1409 | * |
| 1410 | * \see cl_wait() cl_lock_operations::clo_wait() |
| 1411 | * \see cl_lock_state::CLS_HELD |
| 1412 | */ |
| 1413 | int cl_wait_try(const struct lu_env *env, struct cl_lock *lock) |
| 1414 | { |
| 1415 | const struct cl_lock_slice *slice; |
| 1416 | int result; |
| 1417 | |
| 1418 | cl_lock_trace(D_DLMTRACE, env, "wait lock try", lock); |
| 1419 | do { |
| 1420 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 1421 | LINVRNT(cl_lock_invariant(env, lock)); |
| 1422 | LASSERTF(lock->cll_state == CLS_QUEUING || |
| 1423 | lock->cll_state == CLS_ENQUEUED || |
| 1424 | lock->cll_state == CLS_HELD || |
| 1425 | lock->cll_state == CLS_INTRANSIT, |
| 1426 | "lock state: %d\n", lock->cll_state); |
| 1427 | LASSERT(lock->cll_users > 0); |
| 1428 | LASSERT(lock->cll_holds > 0); |
| 1429 | |
| 1430 | result = lock->cll_error; |
| 1431 | if (result != 0) |
| 1432 | break; |
| 1433 | |
| 1434 | if (cl_lock_is_intransit(lock)) { |
| 1435 | result = CLO_WAIT; |
| 1436 | break; |
| 1437 | } |
| 1438 | |
| 1439 | if (lock->cll_state == CLS_HELD) |
| 1440 | /* nothing to do */ |
| 1441 | break; |
| 1442 | |
| 1443 | result = -ENOSYS; |
| 1444 | list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { |
| 1445 | if (slice->cls_ops->clo_wait != NULL) { |
| 1446 | result = slice->cls_ops->clo_wait(env, slice); |
| 1447 | if (result != 0) |
| 1448 | break; |
| 1449 | } |
| 1450 | } |
| 1451 | LASSERT(result != -ENOSYS); |
| 1452 | if (result == 0) { |
| 1453 | LASSERT(lock->cll_state != CLS_INTRANSIT); |
| 1454 | cl_lock_state_set(env, lock, CLS_HELD); |
| 1455 | } |
| 1456 | } while (result == CLO_REPEAT); |
| 1457 | return result; |
| 1458 | } |
| 1459 | EXPORT_SYMBOL(cl_wait_try); |
| 1460 | |
| 1461 | /** |
| 1462 | * Waits until enqueued lock is granted. |
| 1463 | * |
| 1464 | * \pre current thread or io owns a hold on the lock |
| 1465 | * \pre ergo(result == 0, lock->cll_state == CLS_ENQUEUED || |
| 1466 | * lock->cll_state == CLS_HELD) |
| 1467 | * |
| 1468 | * \post ergo(result == 0, lock->cll_state == CLS_HELD) |
| 1469 | */ |
| 1470 | int cl_wait(const struct lu_env *env, struct cl_lock *lock) |
| 1471 | { |
| 1472 | int result; |
| 1473 | |
| 1474 | cl_lock_mutex_get(env, lock); |
| 1475 | |
| 1476 | LINVRNT(cl_lock_invariant(env, lock)); |
| 1477 | LASSERTF(lock->cll_state == CLS_ENQUEUED || lock->cll_state == CLS_HELD, |
| 1478 | "Wrong state %d \n", lock->cll_state); |
| 1479 | LASSERT(lock->cll_holds > 0); |
| 1480 | |
| 1481 | do { |
| 1482 | result = cl_wait_try(env, lock); |
| 1483 | if (result == CLO_WAIT) { |
| 1484 | result = cl_lock_state_wait(env, lock); |
| 1485 | if (result == 0) |
| 1486 | continue; |
| 1487 | } |
| 1488 | break; |
| 1489 | } while (1); |
| 1490 | if (result < 0) { |
| 1491 | cl_unuse_try(env, lock); |
| 1492 | cl_lock_lockdep_release(env, lock); |
| 1493 | } |
| 1494 | cl_lock_trace(D_DLMTRACE, env, "wait lock", lock); |
| 1495 | cl_lock_mutex_put(env, lock); |
| 1496 | LASSERT(ergo(result == 0, lock->cll_state == CLS_HELD)); |
| 1497 | return result; |
| 1498 | } |
| 1499 | EXPORT_SYMBOL(cl_wait); |
| 1500 | |
| 1501 | /** |
| 1502 | * Executes cl_lock_operations::clo_weigh(), and sums results to estimate lock |
| 1503 | * value. |
| 1504 | */ |
| 1505 | unsigned long cl_lock_weigh(const struct lu_env *env, struct cl_lock *lock) |
| 1506 | { |
| 1507 | const struct cl_lock_slice *slice; |
| 1508 | unsigned long pound; |
| 1509 | unsigned long ounce; |
| 1510 | |
| 1511 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 1512 | LINVRNT(cl_lock_invariant(env, lock)); |
| 1513 | |
| 1514 | pound = 0; |
| 1515 | list_for_each_entry_reverse(slice, &lock->cll_layers, cls_linkage) { |
| 1516 | if (slice->cls_ops->clo_weigh != NULL) { |
| 1517 | ounce = slice->cls_ops->clo_weigh(env, slice); |
| 1518 | pound += ounce; |
| 1519 | if (pound < ounce) /* over-weight^Wflow */ |
| 1520 | pound = ~0UL; |
| 1521 | } |
| 1522 | } |
| 1523 | return pound; |
| 1524 | } |
| 1525 | EXPORT_SYMBOL(cl_lock_weigh); |
| 1526 | |
| 1527 | /** |
| 1528 | * Notifies layers that lock description changed. |
| 1529 | * |
| 1530 | * The server can grant client a lock different from one that was requested |
| 1531 | * (e.g., larger in extent). This method is called when actually granted lock |
| 1532 | * description becomes known to let layers to accommodate for changed lock |
| 1533 | * description. |
| 1534 | * |
| 1535 | * \see cl_lock_operations::clo_modify() |
| 1536 | */ |
| 1537 | int cl_lock_modify(const struct lu_env *env, struct cl_lock *lock, |
| 1538 | const struct cl_lock_descr *desc) |
| 1539 | { |
| 1540 | const struct cl_lock_slice *slice; |
| 1541 | struct cl_object *obj = lock->cll_descr.cld_obj; |
| 1542 | struct cl_object_header *hdr = cl_object_header(obj); |
| 1543 | int result; |
| 1544 | |
| 1545 | cl_lock_trace(D_DLMTRACE, env, "modify lock", lock); |
| 1546 | /* don't allow object to change */ |
| 1547 | LASSERT(obj == desc->cld_obj); |
| 1548 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 1549 | LINVRNT(cl_lock_invariant(env, lock)); |
| 1550 | |
| 1551 | list_for_each_entry_reverse(slice, &lock->cll_layers, cls_linkage) { |
| 1552 | if (slice->cls_ops->clo_modify != NULL) { |
| 1553 | result = slice->cls_ops->clo_modify(env, slice, desc); |
| 1554 | if (result != 0) |
| 1555 | return result; |
| 1556 | } |
| 1557 | } |
| 1558 | CL_LOCK_DEBUG(D_DLMTRACE, env, lock, " -> "DDESCR"@"DFID"\n", |
| 1559 | PDESCR(desc), PFID(lu_object_fid(&desc->cld_obj->co_lu))); |
| 1560 | /* |
| 1561 | * Just replace description in place. Nothing more is needed for |
| 1562 | * now. If locks were indexed according to their extent and/or mode, |
| 1563 | * that index would have to be updated here. |
| 1564 | */ |
| 1565 | spin_lock(&hdr->coh_lock_guard); |
| 1566 | lock->cll_descr = *desc; |
| 1567 | spin_unlock(&hdr->coh_lock_guard); |
| 1568 | return 0; |
| 1569 | } |
| 1570 | EXPORT_SYMBOL(cl_lock_modify); |
| 1571 | |
| 1572 | /** |
| 1573 | * Initializes lock closure with a given origin. |
| 1574 | * |
| 1575 | * \see cl_lock_closure |
| 1576 | */ |
| 1577 | void cl_lock_closure_init(const struct lu_env *env, |
| 1578 | struct cl_lock_closure *closure, |
| 1579 | struct cl_lock *origin, int wait) |
| 1580 | { |
| 1581 | LINVRNT(cl_lock_is_mutexed(origin)); |
| 1582 | LINVRNT(cl_lock_invariant(env, origin)); |
| 1583 | |
| 1584 | INIT_LIST_HEAD(&closure->clc_list); |
| 1585 | closure->clc_origin = origin; |
| 1586 | closure->clc_wait = wait; |
| 1587 | closure->clc_nr = 0; |
| 1588 | } |
| 1589 | EXPORT_SYMBOL(cl_lock_closure_init); |
| 1590 | |
| 1591 | /** |
| 1592 | * Builds a closure of \a lock. |
| 1593 | * |
| 1594 | * Building of a closure consists of adding initial lock (\a lock) into it, |
| 1595 | * and calling cl_lock_operations::clo_closure() methods of \a lock. These |
| 1596 | * methods might call cl_lock_closure_build() recursively again, adding more |
| 1597 | * locks to the closure, etc. |
| 1598 | * |
| 1599 | * \see cl_lock_closure |
| 1600 | */ |
| 1601 | int cl_lock_closure_build(const struct lu_env *env, struct cl_lock *lock, |
| 1602 | struct cl_lock_closure *closure) |
| 1603 | { |
| 1604 | const struct cl_lock_slice *slice; |
| 1605 | int result; |
| 1606 | |
| 1607 | LINVRNT(cl_lock_is_mutexed(closure->clc_origin)); |
| 1608 | LINVRNT(cl_lock_invariant(env, closure->clc_origin)); |
| 1609 | |
| 1610 | result = cl_lock_enclosure(env, lock, closure); |
| 1611 | if (result == 0) { |
| 1612 | list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { |
| 1613 | if (slice->cls_ops->clo_closure != NULL) { |
| 1614 | result = slice->cls_ops->clo_closure(env, slice, |
| 1615 | closure); |
| 1616 | if (result != 0) |
| 1617 | break; |
| 1618 | } |
| 1619 | } |
| 1620 | } |
| 1621 | if (result != 0) |
| 1622 | cl_lock_disclosure(env, closure); |
| 1623 | return result; |
| 1624 | } |
| 1625 | EXPORT_SYMBOL(cl_lock_closure_build); |
| 1626 | |
| 1627 | /** |
| 1628 | * Adds new lock to a closure. |
| 1629 | * |
| 1630 | * Try-locks \a lock and if succeeded, adds it to the closure (never more than |
| 1631 | * once). If try-lock failed, returns CLO_REPEAT, after optionally waiting |
| 1632 | * until next try-lock is likely to succeed. |
| 1633 | */ |
| 1634 | int cl_lock_enclosure(const struct lu_env *env, struct cl_lock *lock, |
| 1635 | struct cl_lock_closure *closure) |
| 1636 | { |
| 1637 | int result = 0; |
| 1638 | |
| 1639 | cl_lock_trace(D_DLMTRACE, env, "enclosure lock", lock); |
| 1640 | if (!cl_lock_mutex_try(env, lock)) { |
| 1641 | /* |
| 1642 | * If lock->cll_inclosure is not empty, lock is already in |
| 1643 | * this closure. |
| 1644 | */ |
| 1645 | if (list_empty(&lock->cll_inclosure)) { |
| 1646 | cl_lock_get_trust(lock); |
| 1647 | lu_ref_add(&lock->cll_reference, "closure", closure); |
| 1648 | list_add(&lock->cll_inclosure, &closure->clc_list); |
| 1649 | closure->clc_nr++; |
| 1650 | } else |
| 1651 | cl_lock_mutex_put(env, lock); |
| 1652 | result = 0; |
| 1653 | } else { |
| 1654 | cl_lock_disclosure(env, closure); |
| 1655 | if (closure->clc_wait) { |
| 1656 | cl_lock_get_trust(lock); |
| 1657 | lu_ref_add(&lock->cll_reference, "closure-w", closure); |
| 1658 | cl_lock_mutex_put(env, closure->clc_origin); |
| 1659 | |
| 1660 | LASSERT(cl_lock_nr_mutexed(env) == 0); |
| 1661 | cl_lock_mutex_get(env, lock); |
| 1662 | cl_lock_mutex_put(env, lock); |
| 1663 | |
| 1664 | cl_lock_mutex_get(env, closure->clc_origin); |
| 1665 | lu_ref_del(&lock->cll_reference, "closure-w", closure); |
| 1666 | cl_lock_put(env, lock); |
| 1667 | } |
| 1668 | result = CLO_REPEAT; |
| 1669 | } |
| 1670 | return result; |
| 1671 | } |
| 1672 | EXPORT_SYMBOL(cl_lock_enclosure); |
| 1673 | |
| 1674 | /** Releases mutices of enclosed locks. */ |
| 1675 | void cl_lock_disclosure(const struct lu_env *env, |
| 1676 | struct cl_lock_closure *closure) |
| 1677 | { |
| 1678 | struct cl_lock *scan; |
| 1679 | struct cl_lock *temp; |
| 1680 | |
| 1681 | cl_lock_trace(D_DLMTRACE, env, "disclosure lock", closure->clc_origin); |
| 1682 | list_for_each_entry_safe(scan, temp, &closure->clc_list, |
| 1683 | cll_inclosure){ |
| 1684 | list_del_init(&scan->cll_inclosure); |
| 1685 | cl_lock_mutex_put(env, scan); |
| 1686 | lu_ref_del(&scan->cll_reference, "closure", closure); |
| 1687 | cl_lock_put(env, scan); |
| 1688 | closure->clc_nr--; |
| 1689 | } |
| 1690 | LASSERT(closure->clc_nr == 0); |
| 1691 | } |
| 1692 | EXPORT_SYMBOL(cl_lock_disclosure); |
| 1693 | |
| 1694 | /** Finalizes a closure. */ |
| 1695 | void cl_lock_closure_fini(struct cl_lock_closure *closure) |
| 1696 | { |
| 1697 | LASSERT(closure->clc_nr == 0); |
| 1698 | LASSERT(list_empty(&closure->clc_list)); |
| 1699 | } |
| 1700 | EXPORT_SYMBOL(cl_lock_closure_fini); |
| 1701 | |
| 1702 | /** |
| 1703 | * Destroys this lock. Notifies layers (bottom-to-top) that lock is being |
| 1704 | * destroyed, then destroy the lock. If there are holds on the lock, postpone |
| 1705 | * destruction until all holds are released. This is called when a decision is |
| 1706 | * made to destroy the lock in the future. E.g., when a blocking AST is |
| 1707 | * received on it, or fatal communication error happens. |
| 1708 | * |
| 1709 | * Caller must have a reference on this lock to prevent a situation, when |
| 1710 | * deleted lock lingers in memory for indefinite time, because nobody calls |
| 1711 | * cl_lock_put() to finish it. |
| 1712 | * |
| 1713 | * \pre atomic_read(&lock->cll_ref) > 0 |
| 1714 | * \pre ergo(cl_lock_nesting(lock) == CNL_TOP, |
| 1715 | * cl_lock_nr_mutexed(env) == 1) |
| 1716 | * [i.e., if a top-lock is deleted, mutices of no other locks can be |
| 1717 | * held, as deletion of sub-locks might require releasing a top-lock |
| 1718 | * mutex] |
| 1719 | * |
| 1720 | * \see cl_lock_operations::clo_delete() |
| 1721 | * \see cl_lock::cll_holds |
| 1722 | */ |
| 1723 | void cl_lock_delete(const struct lu_env *env, struct cl_lock *lock) |
| 1724 | { |
| 1725 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 1726 | LINVRNT(cl_lock_invariant(env, lock)); |
| 1727 | LASSERT(ergo(cl_lock_nesting(lock) == CNL_TOP, |
| 1728 | cl_lock_nr_mutexed(env) == 1)); |
| 1729 | |
| 1730 | cl_lock_trace(D_DLMTRACE, env, "delete lock", lock); |
| 1731 | if (lock->cll_holds == 0) |
| 1732 | cl_lock_delete0(env, lock); |
| 1733 | else |
| 1734 | lock->cll_flags |= CLF_DOOMED; |
| 1735 | } |
| 1736 | EXPORT_SYMBOL(cl_lock_delete); |
| 1737 | |
| 1738 | /** |
| 1739 | * Mark lock as irrecoverably failed, and mark it for destruction. This |
| 1740 | * happens when, e.g., server fails to grant a lock to us, or networking |
| 1741 | * time-out happens. |
| 1742 | * |
| 1743 | * \pre atomic_read(&lock->cll_ref) > 0 |
| 1744 | * |
| 1745 | * \see clo_lock_delete() |
| 1746 | * \see cl_lock::cll_holds |
| 1747 | */ |
| 1748 | void cl_lock_error(const struct lu_env *env, struct cl_lock *lock, int error) |
| 1749 | { |
| 1750 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 1751 | LINVRNT(cl_lock_invariant(env, lock)); |
| 1752 | |
| 1753 | if (lock->cll_error == 0 && error != 0) { |
| 1754 | cl_lock_trace(D_DLMTRACE, env, "set lock error", lock); |
| 1755 | lock->cll_error = error; |
| 1756 | cl_lock_signal(env, lock); |
| 1757 | cl_lock_cancel(env, lock); |
| 1758 | cl_lock_delete(env, lock); |
| 1759 | } |
| 1760 | } |
| 1761 | EXPORT_SYMBOL(cl_lock_error); |
| 1762 | |
| 1763 | /** |
| 1764 | * Cancels this lock. Notifies layers |
| 1765 | * (bottom-to-top) that lock is being cancelled, then destroy the lock. If |
| 1766 | * there are holds on the lock, postpone cancellation until |
| 1767 | * all holds are released. |
| 1768 | * |
| 1769 | * Cancellation notification is delivered to layers at most once. |
| 1770 | * |
| 1771 | * \see cl_lock_operations::clo_cancel() |
| 1772 | * \see cl_lock::cll_holds |
| 1773 | */ |
| 1774 | void cl_lock_cancel(const struct lu_env *env, struct cl_lock *lock) |
| 1775 | { |
| 1776 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 1777 | LINVRNT(cl_lock_invariant(env, lock)); |
| 1778 | |
| 1779 | cl_lock_trace(D_DLMTRACE, env, "cancel lock", lock); |
| 1780 | if (lock->cll_holds == 0) |
| 1781 | cl_lock_cancel0(env, lock); |
| 1782 | else |
| 1783 | lock->cll_flags |= CLF_CANCELPEND; |
| 1784 | } |
| 1785 | EXPORT_SYMBOL(cl_lock_cancel); |
| 1786 | |
| 1787 | /** |
| 1788 | * Finds an existing lock covering given index and optionally different from a |
| 1789 | * given \a except lock. |
| 1790 | */ |
| 1791 | struct cl_lock *cl_lock_at_pgoff(const struct lu_env *env, |
| 1792 | struct cl_object *obj, pgoff_t index, |
| 1793 | struct cl_lock *except, |
| 1794 | int pending, int canceld) |
| 1795 | { |
| 1796 | struct cl_object_header *head; |
| 1797 | struct cl_lock *scan; |
| 1798 | struct cl_lock *lock; |
| 1799 | struct cl_lock_descr *need; |
| 1800 | |
| 1801 | head = cl_object_header(obj); |
| 1802 | need = &cl_env_info(env)->clt_descr; |
| 1803 | lock = NULL; |
| 1804 | |
| 1805 | need->cld_mode = CLM_READ; /* CLM_READ matches both READ & WRITE, but |
| 1806 | * not PHANTOM */ |
| 1807 | need->cld_start = need->cld_end = index; |
| 1808 | need->cld_enq_flags = 0; |
| 1809 | |
| 1810 | spin_lock(&head->coh_lock_guard); |
| 1811 | /* It is fine to match any group lock since there could be only one |
| 1812 | * with a uniq gid and it conflicts with all other lock modes too */ |
| 1813 | list_for_each_entry(scan, &head->coh_locks, cll_linkage) { |
| 1814 | if (scan != except && |
| 1815 | (scan->cll_descr.cld_mode == CLM_GROUP || |
| 1816 | cl_lock_ext_match(&scan->cll_descr, need)) && |
| 1817 | scan->cll_state >= CLS_HELD && |
| 1818 | scan->cll_state < CLS_FREEING && |
| 1819 | /* |
| 1820 | * This check is racy as the lock can be canceled right |
| 1821 | * after it is done, but this is fine, because page exists |
| 1822 | * already. |
| 1823 | */ |
| 1824 | (canceld || !(scan->cll_flags & CLF_CANCELLED)) && |
| 1825 | (pending || !(scan->cll_flags & CLF_CANCELPEND))) { |
| 1826 | /* Don't increase cs_hit here since this |
| 1827 | * is just a helper function. */ |
| 1828 | cl_lock_get_trust(scan); |
| 1829 | lock = scan; |
| 1830 | break; |
| 1831 | } |
| 1832 | } |
| 1833 | spin_unlock(&head->coh_lock_guard); |
| 1834 | return lock; |
| 1835 | } |
| 1836 | EXPORT_SYMBOL(cl_lock_at_pgoff); |
| 1837 | |
| 1838 | /** |
| 1839 | * Calculate the page offset at the layer of @lock. |
| 1840 | * At the time of this writing, @page is top page and @lock is sub lock. |
| 1841 | */ |
| 1842 | static pgoff_t pgoff_at_lock(struct cl_page *page, struct cl_lock *lock) |
| 1843 | { |
| 1844 | struct lu_device_type *dtype; |
| 1845 | const struct cl_page_slice *slice; |
| 1846 | |
| 1847 | dtype = lock->cll_descr.cld_obj->co_lu.lo_dev->ld_type; |
| 1848 | slice = cl_page_at(page, dtype); |
| 1849 | LASSERT(slice != NULL); |
| 1850 | return slice->cpl_page->cp_index; |
| 1851 | } |
| 1852 | |
| 1853 | /** |
| 1854 | * Check if page @page is covered by an extra lock or discard it. |
| 1855 | */ |
| 1856 | static int check_and_discard_cb(const struct lu_env *env, struct cl_io *io, |
| 1857 | struct cl_page *page, void *cbdata) |
| 1858 | { |
| 1859 | struct cl_thread_info *info = cl_env_info(env); |
| 1860 | struct cl_lock *lock = cbdata; |
| 1861 | pgoff_t index = pgoff_at_lock(page, lock); |
| 1862 | |
| 1863 | if (index >= info->clt_fn_index) { |
| 1864 | struct cl_lock *tmp; |
| 1865 | |
| 1866 | /* refresh non-overlapped index */ |
| 1867 | tmp = cl_lock_at_pgoff(env, lock->cll_descr.cld_obj, index, |
| 1868 | lock, 1, 0); |
| 1869 | if (tmp != NULL) { |
| 1870 | /* Cache the first-non-overlapped index so as to skip |
| 1871 | * all pages within [index, clt_fn_index). This |
| 1872 | * is safe because if tmp lock is canceled, it will |
| 1873 | * discard these pages. */ |
| 1874 | info->clt_fn_index = tmp->cll_descr.cld_end + 1; |
| 1875 | if (tmp->cll_descr.cld_end == CL_PAGE_EOF) |
| 1876 | info->clt_fn_index = CL_PAGE_EOF; |
| 1877 | cl_lock_put(env, tmp); |
| 1878 | } else if (cl_page_own(env, io, page) == 0) { |
| 1879 | /* discard the page */ |
| 1880 | cl_page_unmap(env, io, page); |
| 1881 | cl_page_discard(env, io, page); |
| 1882 | cl_page_disown(env, io, page); |
| 1883 | } else { |
| 1884 | LASSERT(page->cp_state == CPS_FREEING); |
| 1885 | } |
| 1886 | } |
| 1887 | |
| 1888 | info->clt_next_index = index + 1; |
| 1889 | return CLP_GANG_OKAY; |
| 1890 | } |
| 1891 | |
| 1892 | static int discard_cb(const struct lu_env *env, struct cl_io *io, |
| 1893 | struct cl_page *page, void *cbdata) |
| 1894 | { |
| 1895 | struct cl_thread_info *info = cl_env_info(env); |
| 1896 | struct cl_lock *lock = cbdata; |
| 1897 | |
| 1898 | LASSERT(lock->cll_descr.cld_mode >= CLM_WRITE); |
| 1899 | KLASSERT(ergo(page->cp_type == CPT_CACHEABLE, |
| 1900 | !PageWriteback(cl_page_vmpage(env, page)))); |
| 1901 | KLASSERT(ergo(page->cp_type == CPT_CACHEABLE, |
| 1902 | !PageDirty(cl_page_vmpage(env, page)))); |
| 1903 | |
| 1904 | info->clt_next_index = pgoff_at_lock(page, lock) + 1; |
| 1905 | if (cl_page_own(env, io, page) == 0) { |
| 1906 | /* discard the page */ |
| 1907 | cl_page_unmap(env, io, page); |
| 1908 | cl_page_discard(env, io, page); |
| 1909 | cl_page_disown(env, io, page); |
| 1910 | } else { |
| 1911 | LASSERT(page->cp_state == CPS_FREEING); |
| 1912 | } |
| 1913 | |
| 1914 | return CLP_GANG_OKAY; |
| 1915 | } |
| 1916 | |
| 1917 | /** |
| 1918 | * Discard pages protected by the given lock. This function traverses radix |
| 1919 | * tree to find all covering pages and discard them. If a page is being covered |
| 1920 | * by other locks, it should remain in cache. |
| 1921 | * |
| 1922 | * If error happens on any step, the process continues anyway (the reasoning |
| 1923 | * behind this being that lock cancellation cannot be delayed indefinitely). |
| 1924 | */ |
| 1925 | int cl_lock_discard_pages(const struct lu_env *env, struct cl_lock *lock) |
| 1926 | { |
| 1927 | struct cl_thread_info *info = cl_env_info(env); |
| 1928 | struct cl_io *io = &info->clt_io; |
| 1929 | struct cl_lock_descr *descr = &lock->cll_descr; |
| 1930 | cl_page_gang_cb_t cb; |
| 1931 | int res; |
| 1932 | int result; |
| 1933 | |
| 1934 | LINVRNT(cl_lock_invariant(env, lock)); |
| 1935 | |
| 1936 | io->ci_obj = cl_object_top(descr->cld_obj); |
| 1937 | io->ci_ignore_layout = 1; |
| 1938 | result = cl_io_init(env, io, CIT_MISC, io->ci_obj); |
| 1939 | if (result != 0) |
| 1940 | goto out; |
| 1941 | |
| 1942 | cb = descr->cld_mode == CLM_READ ? check_and_discard_cb : discard_cb; |
| 1943 | info->clt_fn_index = info->clt_next_index = descr->cld_start; |
| 1944 | do { |
| 1945 | res = cl_page_gang_lookup(env, descr->cld_obj, io, |
| 1946 | info->clt_next_index, descr->cld_end, |
| 1947 | cb, (void *)lock); |
| 1948 | if (info->clt_next_index > descr->cld_end) |
| 1949 | break; |
| 1950 | |
| 1951 | if (res == CLP_GANG_RESCHED) |
| 1952 | cond_resched(); |
| 1953 | } while (res != CLP_GANG_OKAY); |
| 1954 | out: |
| 1955 | cl_io_fini(env, io); |
| 1956 | return result; |
| 1957 | } |
| 1958 | EXPORT_SYMBOL(cl_lock_discard_pages); |
| 1959 | |
| 1960 | /** |
| 1961 | * Eliminate all locks for a given object. |
| 1962 | * |
| 1963 | * Caller has to guarantee that no lock is in active use. |
| 1964 | * |
| 1965 | * \param cancel when this is set, cl_locks_prune() cancels locks before |
| 1966 | * destroying. |
| 1967 | */ |
| 1968 | void cl_locks_prune(const struct lu_env *env, struct cl_object *obj, int cancel) |
| 1969 | { |
| 1970 | struct cl_object_header *head; |
| 1971 | struct cl_lock *lock; |
| 1972 | |
| 1973 | head = cl_object_header(obj); |
| 1974 | /* |
| 1975 | * If locks are destroyed without cancellation, all pages must be |
| 1976 | * already destroyed (as otherwise they will be left unprotected). |
| 1977 | */ |
| 1978 | LASSERT(ergo(!cancel, |
| 1979 | head->coh_tree.rnode == NULL && head->coh_pages == 0)); |
| 1980 | |
| 1981 | spin_lock(&head->coh_lock_guard); |
| 1982 | while (!list_empty(&head->coh_locks)) { |
| 1983 | lock = container_of(head->coh_locks.next, |
| 1984 | struct cl_lock, cll_linkage); |
| 1985 | cl_lock_get_trust(lock); |
| 1986 | spin_unlock(&head->coh_lock_guard); |
| 1987 | lu_ref_add(&lock->cll_reference, "prune", current); |
| 1988 | |
| 1989 | again: |
| 1990 | cl_lock_mutex_get(env, lock); |
| 1991 | if (lock->cll_state < CLS_FREEING) { |
| 1992 | LASSERT(lock->cll_users <= 1); |
| 1993 | if (unlikely(lock->cll_users == 1)) { |
| 1994 | struct l_wait_info lwi = { 0 }; |
| 1995 | |
| 1996 | cl_lock_mutex_put(env, lock); |
| 1997 | l_wait_event(lock->cll_wq, |
| 1998 | lock->cll_users == 0, |
| 1999 | &lwi); |
| 2000 | goto again; |
| 2001 | } |
| 2002 | |
| 2003 | if (cancel) |
| 2004 | cl_lock_cancel(env, lock); |
| 2005 | cl_lock_delete(env, lock); |
| 2006 | } |
| 2007 | cl_lock_mutex_put(env, lock); |
| 2008 | lu_ref_del(&lock->cll_reference, "prune", current); |
| 2009 | cl_lock_put(env, lock); |
| 2010 | spin_lock(&head->coh_lock_guard); |
| 2011 | } |
| 2012 | spin_unlock(&head->coh_lock_guard); |
| 2013 | } |
| 2014 | EXPORT_SYMBOL(cl_locks_prune); |
| 2015 | |
| 2016 | static struct cl_lock *cl_lock_hold_mutex(const struct lu_env *env, |
| 2017 | const struct cl_io *io, |
| 2018 | const struct cl_lock_descr *need, |
| 2019 | const char *scope, const void *source) |
| 2020 | { |
| 2021 | struct cl_lock *lock; |
| 2022 | |
| 2023 | while (1) { |
| 2024 | lock = cl_lock_find(env, io, need); |
| 2025 | if (IS_ERR(lock)) |
| 2026 | break; |
| 2027 | cl_lock_mutex_get(env, lock); |
| 2028 | if (lock->cll_state < CLS_FREEING && |
| 2029 | !(lock->cll_flags & CLF_CANCELLED)) { |
| 2030 | cl_lock_hold_mod(env, lock, 1); |
| 2031 | lu_ref_add(&lock->cll_holders, scope, source); |
| 2032 | lu_ref_add(&lock->cll_reference, scope, source); |
| 2033 | break; |
| 2034 | } |
| 2035 | cl_lock_mutex_put(env, lock); |
| 2036 | cl_lock_put(env, lock); |
| 2037 | } |
| 2038 | return lock; |
| 2039 | } |
| 2040 | |
| 2041 | /** |
| 2042 | * Returns a lock matching \a need description with a reference and a hold on |
| 2043 | * it. |
| 2044 | * |
| 2045 | * This is much like cl_lock_find(), except that cl_lock_hold() additionally |
| 2046 | * guarantees that lock is not in the CLS_FREEING state on return. |
| 2047 | */ |
| 2048 | struct cl_lock *cl_lock_hold(const struct lu_env *env, const struct cl_io *io, |
| 2049 | const struct cl_lock_descr *need, |
| 2050 | const char *scope, const void *source) |
| 2051 | { |
| 2052 | struct cl_lock *lock; |
| 2053 | |
| 2054 | lock = cl_lock_hold_mutex(env, io, need, scope, source); |
| 2055 | if (!IS_ERR(lock)) |
| 2056 | cl_lock_mutex_put(env, lock); |
| 2057 | return lock; |
| 2058 | } |
| 2059 | EXPORT_SYMBOL(cl_lock_hold); |
| 2060 | |
| 2061 | /** |
| 2062 | * Main high-level entry point of cl_lock interface that finds existing or |
| 2063 | * enqueues new lock matching given description. |
| 2064 | */ |
| 2065 | struct cl_lock *cl_lock_request(const struct lu_env *env, struct cl_io *io, |
| 2066 | const struct cl_lock_descr *need, |
| 2067 | const char *scope, const void *source) |
| 2068 | { |
| 2069 | struct cl_lock *lock; |
| 2070 | int rc; |
| 2071 | __u32 enqflags = need->cld_enq_flags; |
| 2072 | |
| 2073 | do { |
| 2074 | lock = cl_lock_hold_mutex(env, io, need, scope, source); |
| 2075 | if (IS_ERR(lock)) |
| 2076 | break; |
| 2077 | |
| 2078 | rc = cl_enqueue_locked(env, lock, io, enqflags); |
| 2079 | if (rc == 0) { |
| 2080 | if (cl_lock_fits_into(env, lock, need, io)) { |
| 2081 | if (!(enqflags & CEF_AGL)) { |
| 2082 | cl_lock_mutex_put(env, lock); |
| 2083 | cl_lock_lockdep_acquire(env, lock, |
| 2084 | enqflags); |
| 2085 | break; |
| 2086 | } |
| 2087 | rc = 1; |
| 2088 | } |
| 2089 | cl_unuse_locked(env, lock); |
| 2090 | } |
| 2091 | cl_lock_trace(D_DLMTRACE, env, |
| 2092 | rc <= 0 ? "enqueue failed" : "agl succeed", lock); |
| 2093 | cl_lock_hold_release(env, lock, scope, source); |
| 2094 | cl_lock_mutex_put(env, lock); |
| 2095 | lu_ref_del(&lock->cll_reference, scope, source); |
| 2096 | cl_lock_put(env, lock); |
| 2097 | if (rc > 0) { |
| 2098 | LASSERT(enqflags & CEF_AGL); |
| 2099 | lock = NULL; |
| 2100 | } else if (rc != 0) { |
| 2101 | lock = ERR_PTR(rc); |
| 2102 | } |
| 2103 | } while (rc == 0); |
| 2104 | return lock; |
| 2105 | } |
| 2106 | EXPORT_SYMBOL(cl_lock_request); |
| 2107 | |
| 2108 | /** |
| 2109 | * Adds a hold to a known lock. |
| 2110 | */ |
| 2111 | void cl_lock_hold_add(const struct lu_env *env, struct cl_lock *lock, |
| 2112 | const char *scope, const void *source) |
| 2113 | { |
| 2114 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 2115 | LINVRNT(cl_lock_invariant(env, lock)); |
| 2116 | LASSERT(lock->cll_state != CLS_FREEING); |
| 2117 | |
| 2118 | cl_lock_hold_mod(env, lock, 1); |
| 2119 | cl_lock_get(lock); |
| 2120 | lu_ref_add(&lock->cll_holders, scope, source); |
| 2121 | lu_ref_add(&lock->cll_reference, scope, source); |
| 2122 | } |
| 2123 | EXPORT_SYMBOL(cl_lock_hold_add); |
| 2124 | |
| 2125 | /** |
| 2126 | * Releases a hold and a reference on a lock, on which caller acquired a |
| 2127 | * mutex. |
| 2128 | */ |
| 2129 | void cl_lock_unhold(const struct lu_env *env, struct cl_lock *lock, |
| 2130 | const char *scope, const void *source) |
| 2131 | { |
| 2132 | LINVRNT(cl_lock_invariant(env, lock)); |
| 2133 | cl_lock_hold_release(env, lock, scope, source); |
| 2134 | lu_ref_del(&lock->cll_reference, scope, source); |
| 2135 | cl_lock_put(env, lock); |
| 2136 | } |
| 2137 | EXPORT_SYMBOL(cl_lock_unhold); |
| 2138 | |
| 2139 | /** |
| 2140 | * Releases a hold and a reference on a lock, obtained by cl_lock_hold(). |
| 2141 | */ |
| 2142 | void cl_lock_release(const struct lu_env *env, struct cl_lock *lock, |
| 2143 | const char *scope, const void *source) |
| 2144 | { |
| 2145 | LINVRNT(cl_lock_invariant(env, lock)); |
| 2146 | cl_lock_trace(D_DLMTRACE, env, "release lock", lock); |
| 2147 | cl_lock_mutex_get(env, lock); |
| 2148 | cl_lock_hold_release(env, lock, scope, source); |
| 2149 | cl_lock_mutex_put(env, lock); |
| 2150 | lu_ref_del(&lock->cll_reference, scope, source); |
| 2151 | cl_lock_put(env, lock); |
| 2152 | } |
| 2153 | EXPORT_SYMBOL(cl_lock_release); |
| 2154 | |
| 2155 | void cl_lock_user_add(const struct lu_env *env, struct cl_lock *lock) |
| 2156 | { |
| 2157 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 2158 | LINVRNT(cl_lock_invariant(env, lock)); |
| 2159 | |
| 2160 | cl_lock_used_mod(env, lock, 1); |
| 2161 | } |
| 2162 | EXPORT_SYMBOL(cl_lock_user_add); |
| 2163 | |
| 2164 | void cl_lock_user_del(const struct lu_env *env, struct cl_lock *lock) |
| 2165 | { |
| 2166 | LINVRNT(cl_lock_is_mutexed(lock)); |
| 2167 | LINVRNT(cl_lock_invariant(env, lock)); |
| 2168 | LASSERT(lock->cll_users > 0); |
| 2169 | |
| 2170 | cl_lock_used_mod(env, lock, -1); |
| 2171 | if (lock->cll_users == 0) |
| 2172 | wake_up_all(&lock->cll_wq); |
| 2173 | } |
| 2174 | EXPORT_SYMBOL(cl_lock_user_del); |
| 2175 | |
| 2176 | const char *cl_lock_mode_name(const enum cl_lock_mode mode) |
| 2177 | { |
| 2178 | static const char *names[] = { |
| 2179 | [CLM_PHANTOM] = "P", |
| 2180 | [CLM_READ] = "R", |
| 2181 | [CLM_WRITE] = "W", |
| 2182 | [CLM_GROUP] = "G" |
| 2183 | }; |
| 2184 | if (0 <= mode && mode < ARRAY_SIZE(names)) |
| 2185 | return names[mode]; |
| 2186 | else |
| 2187 | return "U"; |
| 2188 | } |
| 2189 | EXPORT_SYMBOL(cl_lock_mode_name); |
| 2190 | |
| 2191 | /** |
| 2192 | * Prints human readable representation of a lock description. |
| 2193 | */ |
| 2194 | void cl_lock_descr_print(const struct lu_env *env, void *cookie, |
| 2195 | lu_printer_t printer, |
| 2196 | const struct cl_lock_descr *descr) |
| 2197 | { |
| 2198 | const struct lu_fid *fid; |
| 2199 | |
| 2200 | fid = lu_object_fid(&descr->cld_obj->co_lu); |
| 2201 | (*printer)(env, cookie, DDESCR"@"DFID, PDESCR(descr), PFID(fid)); |
| 2202 | } |
| 2203 | EXPORT_SYMBOL(cl_lock_descr_print); |
| 2204 | |
| 2205 | /** |
| 2206 | * Prints human readable representation of \a lock to the \a f. |
| 2207 | */ |
| 2208 | void cl_lock_print(const struct lu_env *env, void *cookie, |
| 2209 | lu_printer_t printer, const struct cl_lock *lock) |
| 2210 | { |
| 2211 | const struct cl_lock_slice *slice; |
| 2212 | (*printer)(env, cookie, "lock@%p[%d %d %d %d %d %08lx] ", |
| 2213 | lock, atomic_read(&lock->cll_ref), |
| 2214 | lock->cll_state, lock->cll_error, lock->cll_holds, |
| 2215 | lock->cll_users, lock->cll_flags); |
| 2216 | cl_lock_descr_print(env, cookie, printer, &lock->cll_descr); |
| 2217 | (*printer)(env, cookie, " {\n"); |
| 2218 | |
| 2219 | list_for_each_entry(slice, &lock->cll_layers, cls_linkage) { |
| 2220 | (*printer)(env, cookie, " %s@%p: ", |
| 2221 | slice->cls_obj->co_lu.lo_dev->ld_type->ldt_name, |
| 2222 | slice); |
| 2223 | if (slice->cls_ops->clo_print != NULL) |
| 2224 | slice->cls_ops->clo_print(env, cookie, printer, slice); |
| 2225 | (*printer)(env, cookie, "\n"); |
| 2226 | } |
| 2227 | (*printer)(env, cookie, "} lock@%p\n", lock); |
| 2228 | } |
| 2229 | EXPORT_SYMBOL(cl_lock_print); |
| 2230 | |
| 2231 | int cl_lock_init(void) |
| 2232 | { |
| 2233 | return lu_kmem_init(cl_lock_caches); |
| 2234 | } |
| 2235 | |
| 2236 | void cl_lock_fini(void) |
| 2237 | { |
| 2238 | lu_kmem_fini(cl_lock_caches); |
| 2239 | } |