1 /* 2 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc. 3 * Copyright (c) 2008 Dave Chinner 4 * All Rights Reserved. 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation. 9 * 10 * This program is distributed in the hope that it would be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, write the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 18 */ 19 #include "xfs.h" 20 #include "xfs_fs.h" 21 #include "xfs_format.h" 22 #include "xfs_log_format.h" 23 #include "xfs_trans_resv.h" 24 #include "xfs_mount.h" 25 #include "xfs_trans.h" 26 #include "xfs_trans_priv.h" 27 #include "xfs_trace.h" 28 #include "xfs_errortag.h" 29 #include "xfs_error.h" 30 #include "xfs_log.h" 31 32 #ifdef DEBUG 33 /* 34 * Check that the list is sorted as it should be. 35 * 36 * Called with the ail lock held, but we don't want to assert fail with it 37 * held otherwise we'll lock everything up and won't be able to debug the 38 * cause. Hence we sample and check the state under the AIL lock and return if 39 * everything is fine, otherwise we drop the lock and run the ASSERT checks. 40 * Asserts may not be fatal, so pick the lock back up and continue onwards. 41 */ 42 STATIC void 43 xfs_ail_check( 44 struct xfs_ail *ailp, 45 struct xfs_log_item *lip) 46 { 47 struct xfs_log_item *prev_lip; 48 struct xfs_log_item *next_lip; 49 xfs_lsn_t prev_lsn = NULLCOMMITLSN; 50 xfs_lsn_t next_lsn = NULLCOMMITLSN; 51 xfs_lsn_t lsn; 52 bool in_ail; 53 54 55 if (list_empty(&ailp->ail_head)) 56 return; 57 58 /* 59 * Sample then check the next and previous entries are valid. 60 */ 61 in_ail = test_bit(XFS_LI_IN_AIL, &lip->li_flags); 62 prev_lip = list_entry(lip->li_ail.prev, struct xfs_log_item, li_ail); 63 if (&prev_lip->li_ail != &ailp->ail_head) 64 prev_lsn = prev_lip->li_lsn; 65 next_lip = list_entry(lip->li_ail.next, struct xfs_log_item, li_ail); 66 if (&next_lip->li_ail != &ailp->ail_head) 67 next_lsn = next_lip->li_lsn; 68 lsn = lip->li_lsn; 69 70 if (in_ail && 71 (prev_lsn == NULLCOMMITLSN || XFS_LSN_CMP(prev_lsn, lsn) <= 0) && 72 (next_lsn == NULLCOMMITLSN || XFS_LSN_CMP(next_lsn, lsn) >= 0)) 73 return; 74 75 spin_unlock(&ailp->ail_lock); 76 ASSERT(in_ail); 77 ASSERT(prev_lsn == NULLCOMMITLSN || XFS_LSN_CMP(prev_lsn, lsn) <= 0); 78 ASSERT(next_lsn == NULLCOMMITLSN || XFS_LSN_CMP(next_lsn, lsn) >= 0); 79 spin_lock(&ailp->ail_lock); 80 } 81 #else /* !DEBUG */ 82 #define xfs_ail_check(a,l) 83 #endif /* DEBUG */ 84 85 /* 86 * Return a pointer to the last item in the AIL. If the AIL is empty, then 87 * return NULL. 88 */ 89 static xfs_log_item_t * 90 xfs_ail_max( 91 struct xfs_ail *ailp) 92 { 93 if (list_empty(&ailp->ail_head)) 94 return NULL; 95 96 return list_entry(ailp->ail_head.prev, xfs_log_item_t, li_ail); 97 } 98 99 /* 100 * Return a pointer to the item which follows the given item in the AIL. If 101 * the given item is the last item in the list, then return NULL. 102 */ 103 static xfs_log_item_t * 104 xfs_ail_next( 105 struct xfs_ail *ailp, 106 xfs_log_item_t *lip) 107 { 108 if (lip->li_ail.next == &ailp->ail_head) 109 return NULL; 110 111 return list_first_entry(&lip->li_ail, xfs_log_item_t, li_ail); 112 } 113 114 /* 115 * This is called by the log manager code to determine the LSN of the tail of 116 * the log. This is exactly the LSN of the first item in the AIL. If the AIL 117 * is empty, then this function returns 0. 118 * 119 * We need the AIL lock in order to get a coherent read of the lsn of the last 120 * item in the AIL. 121 */ 122 xfs_lsn_t 123 xfs_ail_min_lsn( 124 struct xfs_ail *ailp) 125 { 126 xfs_lsn_t lsn = 0; 127 xfs_log_item_t *lip; 128 129 spin_lock(&ailp->ail_lock); 130 lip = xfs_ail_min(ailp); 131 if (lip) 132 lsn = lip->li_lsn; 133 spin_unlock(&ailp->ail_lock); 134 135 return lsn; 136 } 137 138 /* 139 * Return the maximum lsn held in the AIL, or zero if the AIL is empty. 140 */ 141 static xfs_lsn_t 142 xfs_ail_max_lsn( 143 struct xfs_ail *ailp) 144 { 145 xfs_lsn_t lsn = 0; 146 xfs_log_item_t *lip; 147 148 spin_lock(&ailp->ail_lock); 149 lip = xfs_ail_max(ailp); 150 if (lip) 151 lsn = lip->li_lsn; 152 spin_unlock(&ailp->ail_lock); 153 154 return lsn; 155 } 156 157 /* 158 * The cursor keeps track of where our current traversal is up to by tracking 159 * the next item in the list for us. However, for this to be safe, removing an 160 * object from the AIL needs to invalidate any cursor that points to it. hence 161 * the traversal cursor needs to be linked to the struct xfs_ail so that 162 * deletion can search all the active cursors for invalidation. 163 */ 164 STATIC void 165 xfs_trans_ail_cursor_init( 166 struct xfs_ail *ailp, 167 struct xfs_ail_cursor *cur) 168 { 169 cur->item = NULL; 170 list_add_tail(&cur->list, &ailp->ail_cursors); 171 } 172 173 /* 174 * Get the next item in the traversal and advance the cursor. If the cursor 175 * was invalidated (indicated by a lip of 1), restart the traversal. 176 */ 177 struct xfs_log_item * 178 xfs_trans_ail_cursor_next( 179 struct xfs_ail *ailp, 180 struct xfs_ail_cursor *cur) 181 { 182 struct xfs_log_item *lip = cur->item; 183 184 if ((uintptr_t)lip & 1) 185 lip = xfs_ail_min(ailp); 186 if (lip) 187 cur->item = xfs_ail_next(ailp, lip); 188 return lip; 189 } 190 191 /* 192 * When the traversal is complete, we need to remove the cursor from the list 193 * of traversing cursors. 194 */ 195 void 196 xfs_trans_ail_cursor_done( 197 struct xfs_ail_cursor *cur) 198 { 199 cur->item = NULL; 200 list_del_init(&cur->list); 201 } 202 203 /* 204 * Invalidate any cursor that is pointing to this item. This is called when an 205 * item is removed from the AIL. Any cursor pointing to this object is now 206 * invalid and the traversal needs to be terminated so it doesn't reference a 207 * freed object. We set the low bit of the cursor item pointer so we can 208 * distinguish between an invalidation and the end of the list when getting the 209 * next item from the cursor. 210 */ 211 STATIC void 212 xfs_trans_ail_cursor_clear( 213 struct xfs_ail *ailp, 214 struct xfs_log_item *lip) 215 { 216 struct xfs_ail_cursor *cur; 217 218 list_for_each_entry(cur, &ailp->ail_cursors, list) { 219 if (cur->item == lip) 220 cur->item = (struct xfs_log_item *) 221 ((uintptr_t)cur->item | 1); 222 } 223 } 224 225 /* 226 * Find the first item in the AIL with the given @lsn by searching in ascending 227 * LSN order and initialise the cursor to point to the next item for a 228 * ascending traversal. Pass a @lsn of zero to initialise the cursor to the 229 * first item in the AIL. Returns NULL if the list is empty. 230 */ 231 xfs_log_item_t * 232 xfs_trans_ail_cursor_first( 233 struct xfs_ail *ailp, 234 struct xfs_ail_cursor *cur, 235 xfs_lsn_t lsn) 236 { 237 xfs_log_item_t *lip; 238 239 xfs_trans_ail_cursor_init(ailp, cur); 240 241 if (lsn == 0) { 242 lip = xfs_ail_min(ailp); 243 goto out; 244 } 245 246 list_for_each_entry(lip, &ailp->ail_head, li_ail) { 247 if (XFS_LSN_CMP(lip->li_lsn, lsn) >= 0) 248 goto out; 249 } 250 return NULL; 251 252 out: 253 if (lip) 254 cur->item = xfs_ail_next(ailp, lip); 255 return lip; 256 } 257 258 static struct xfs_log_item * 259 __xfs_trans_ail_cursor_last( 260 struct xfs_ail *ailp, 261 xfs_lsn_t lsn) 262 { 263 xfs_log_item_t *lip; 264 265 list_for_each_entry_reverse(lip, &ailp->ail_head, li_ail) { 266 if (XFS_LSN_CMP(lip->li_lsn, lsn) <= 0) 267 return lip; 268 } 269 return NULL; 270 } 271 272 /* 273 * Find the last item in the AIL with the given @lsn by searching in descending 274 * LSN order and initialise the cursor to point to that item. If there is no 275 * item with the value of @lsn, then it sets the cursor to the last item with an 276 * LSN lower than @lsn. Returns NULL if the list is empty. 277 */ 278 struct xfs_log_item * 279 xfs_trans_ail_cursor_last( 280 struct xfs_ail *ailp, 281 struct xfs_ail_cursor *cur, 282 xfs_lsn_t lsn) 283 { 284 xfs_trans_ail_cursor_init(ailp, cur); 285 cur->item = __xfs_trans_ail_cursor_last(ailp, lsn); 286 return cur->item; 287 } 288 289 /* 290 * Splice the log item list into the AIL at the given LSN. We splice to the 291 * tail of the given LSN to maintain insert order for push traversals. The 292 * cursor is optional, allowing repeated updates to the same LSN to avoid 293 * repeated traversals. This should not be called with an empty list. 294 */ 295 static void 296 xfs_ail_splice( 297 struct xfs_ail *ailp, 298 struct xfs_ail_cursor *cur, 299 struct list_head *list, 300 xfs_lsn_t lsn) 301 { 302 struct xfs_log_item *lip; 303 304 ASSERT(!list_empty(list)); 305 306 /* 307 * Use the cursor to determine the insertion point if one is 308 * provided. If not, or if the one we got is not valid, 309 * find the place in the AIL where the items belong. 310 */ 311 lip = cur ? cur->item : NULL; 312 if (!lip || (uintptr_t)lip & 1) 313 lip = __xfs_trans_ail_cursor_last(ailp, lsn); 314 315 /* 316 * If a cursor is provided, we know we're processing the AIL 317 * in lsn order, and future items to be spliced in will 318 * follow the last one being inserted now. Update the 319 * cursor to point to that last item, now while we have a 320 * reliable pointer to it. 321 */ 322 if (cur) 323 cur->item = list_entry(list->prev, struct xfs_log_item, li_ail); 324 325 /* 326 * Finally perform the splice. Unless the AIL was empty, 327 * lip points to the item in the AIL _after_ which the new 328 * items should go. If lip is null the AIL was empty, so 329 * the new items go at the head of the AIL. 330 */ 331 if (lip) 332 list_splice(list, &lip->li_ail); 333 else 334 list_splice(list, &ailp->ail_head); 335 } 336 337 /* 338 * Delete the given item from the AIL. Return a pointer to the item. 339 */ 340 static void 341 xfs_ail_delete( 342 struct xfs_ail *ailp, 343 xfs_log_item_t *lip) 344 { 345 xfs_ail_check(ailp, lip); 346 list_del(&lip->li_ail); 347 xfs_trans_ail_cursor_clear(ailp, lip); 348 } 349 350 static inline uint 351 xfsaild_push_item( 352 struct xfs_ail *ailp, 353 struct xfs_log_item *lip) 354 { 355 /* 356 * If log item pinning is enabled, skip the push and track the item as 357 * pinned. This can help induce head-behind-tail conditions. 358 */ 359 if (XFS_TEST_ERROR(false, ailp->ail_mount, XFS_ERRTAG_LOG_ITEM_PIN)) 360 return XFS_ITEM_PINNED; 361 362 return lip->li_ops->iop_push(lip, &ailp->ail_buf_list); 363 } 364 365 static long 366 xfsaild_push( 367 struct xfs_ail *ailp) 368 { 369 xfs_mount_t *mp = ailp->ail_mount; 370 struct xfs_ail_cursor cur; 371 xfs_log_item_t *lip; 372 xfs_lsn_t lsn; 373 xfs_lsn_t target; 374 long tout; 375 int stuck = 0; 376 int flushing = 0; 377 int count = 0; 378 379 /* 380 * If we encountered pinned items or did not finish writing out all 381 * buffers the last time we ran, force the log first and wait for it 382 * before pushing again. 383 */ 384 if (ailp->ail_log_flush && ailp->ail_last_pushed_lsn == 0 && 385 (!list_empty_careful(&ailp->ail_buf_list) || 386 xfs_ail_min_lsn(ailp))) { 387 ailp->ail_log_flush = 0; 388 389 XFS_STATS_INC(mp, xs_push_ail_flush); 390 xfs_log_force(mp, XFS_LOG_SYNC); 391 } 392 393 spin_lock(&ailp->ail_lock); 394 395 /* barrier matches the ail_target update in xfs_ail_push() */ 396 smp_rmb(); 397 target = ailp->ail_target; 398 ailp->ail_target_prev = target; 399 400 lip = xfs_trans_ail_cursor_first(ailp, &cur, ailp->ail_last_pushed_lsn); 401 if (!lip) { 402 /* 403 * If the AIL is empty or our push has reached the end we are 404 * done now. 405 */ 406 xfs_trans_ail_cursor_done(&cur); 407 spin_unlock(&ailp->ail_lock); 408 goto out_done; 409 } 410 411 XFS_STATS_INC(mp, xs_push_ail); 412 413 lsn = lip->li_lsn; 414 while ((XFS_LSN_CMP(lip->li_lsn, target) <= 0)) { 415 int lock_result; 416 417 /* 418 * Note that iop_push may unlock and reacquire the AIL lock. We 419 * rely on the AIL cursor implementation to be able to deal with 420 * the dropped lock. 421 */ 422 lock_result = xfsaild_push_item(ailp, lip); 423 switch (lock_result) { 424 case XFS_ITEM_SUCCESS: 425 XFS_STATS_INC(mp, xs_push_ail_success); 426 trace_xfs_ail_push(lip); 427 428 ailp->ail_last_pushed_lsn = lsn; 429 break; 430 431 case XFS_ITEM_FLUSHING: 432 /* 433 * The item or its backing buffer is already beeing 434 * flushed. The typical reason for that is that an 435 * inode buffer is locked because we already pushed the 436 * updates to it as part of inode clustering. 437 * 438 * We do not want to to stop flushing just because lots 439 * of items are already beeing flushed, but we need to 440 * re-try the flushing relatively soon if most of the 441 * AIL is beeing flushed. 442 */ 443 XFS_STATS_INC(mp, xs_push_ail_flushing); 444 trace_xfs_ail_flushing(lip); 445 446 flushing++; 447 ailp->ail_last_pushed_lsn = lsn; 448 break; 449 450 case XFS_ITEM_PINNED: 451 XFS_STATS_INC(mp, xs_push_ail_pinned); 452 trace_xfs_ail_pinned(lip); 453 454 stuck++; 455 ailp->ail_log_flush++; 456 break; 457 case XFS_ITEM_LOCKED: 458 XFS_STATS_INC(mp, xs_push_ail_locked); 459 trace_xfs_ail_locked(lip); 460 461 stuck++; 462 break; 463 default: 464 ASSERT(0); 465 break; 466 } 467 468 count++; 469 470 /* 471 * Are there too many items we can't do anything with? 472 * 473 * If we we are skipping too many items because we can't flush 474 * them or they are already being flushed, we back off and 475 * given them time to complete whatever operation is being 476 * done. i.e. remove pressure from the AIL while we can't make 477 * progress so traversals don't slow down further inserts and 478 * removals to/from the AIL. 479 * 480 * The value of 100 is an arbitrary magic number based on 481 * observation. 482 */ 483 if (stuck > 100) 484 break; 485 486 lip = xfs_trans_ail_cursor_next(ailp, &cur); 487 if (lip == NULL) 488 break; 489 lsn = lip->li_lsn; 490 } 491 xfs_trans_ail_cursor_done(&cur); 492 spin_unlock(&ailp->ail_lock); 493 494 if (xfs_buf_delwri_submit_nowait(&ailp->ail_buf_list)) 495 ailp->ail_log_flush++; 496 497 if (!count || XFS_LSN_CMP(lsn, target) >= 0) { 498 out_done: 499 /* 500 * We reached the target or the AIL is empty, so wait a bit 501 * longer for I/O to complete and remove pushed items from the 502 * AIL before we start the next scan from the start of the AIL. 503 */ 504 tout = 50; 505 ailp->ail_last_pushed_lsn = 0; 506 } else if (((stuck + flushing) * 100) / count > 90) { 507 /* 508 * Either there is a lot of contention on the AIL or we are 509 * stuck due to operations in progress. "Stuck" in this case 510 * is defined as >90% of the items we tried to push were stuck. 511 * 512 * Backoff a bit more to allow some I/O to complete before 513 * restarting from the start of the AIL. This prevents us from 514 * spinning on the same items, and if they are pinned will all 515 * the restart to issue a log force to unpin the stuck items. 516 */ 517 tout = 20; 518 ailp->ail_last_pushed_lsn = 0; 519 } else { 520 /* 521 * Assume we have more work to do in a short while. 522 */ 523 tout = 10; 524 } 525 526 return tout; 527 } 528 529 static int 530 xfsaild( 531 void *data) 532 { 533 struct xfs_ail *ailp = data; 534 long tout = 0; /* milliseconds */ 535 536 current->flags |= PF_MEMALLOC; 537 set_freezable(); 538 539 while (1) { 540 if (tout && tout <= 20) 541 set_current_state(TASK_KILLABLE); 542 else 543 set_current_state(TASK_INTERRUPTIBLE); 544 545 /* 546 * Check kthread_should_stop() after we set the task state 547 * to guarantee that we either see the stop bit and exit or 548 * the task state is reset to runnable such that it's not 549 * scheduled out indefinitely and detects the stop bit at 550 * next iteration. 551 * 552 * A memory barrier is included in above task state set to 553 * serialize again kthread_stop(). 554 */ 555 if (kthread_should_stop()) { 556 __set_current_state(TASK_RUNNING); 557 break; 558 } 559 560 spin_lock(&ailp->ail_lock); 561 562 /* 563 * Idle if the AIL is empty and we are not racing with a target 564 * update. We check the AIL after we set the task to a sleep 565 * state to guarantee that we either catch an ail_target update 566 * or that a wake_up resets the state to TASK_RUNNING. 567 * Otherwise, we run the risk of sleeping indefinitely. 568 * 569 * The barrier matches the ail_target update in xfs_ail_push(). 570 */ 571 smp_rmb(); 572 if (!xfs_ail_min(ailp) && 573 ailp->ail_target == ailp->ail_target_prev) { 574 spin_unlock(&ailp->ail_lock); 575 freezable_schedule(); 576 tout = 0; 577 continue; 578 } 579 spin_unlock(&ailp->ail_lock); 580 581 if (tout) 582 freezable_schedule_timeout(msecs_to_jiffies(tout)); 583 584 __set_current_state(TASK_RUNNING); 585 586 try_to_freeze(); 587 588 tout = xfsaild_push(ailp); 589 } 590 591 return 0; 592 } 593 594 /* 595 * This routine is called to move the tail of the AIL forward. It does this by 596 * trying to flush items in the AIL whose lsns are below the given 597 * threshold_lsn. 598 * 599 * The push is run asynchronously in a workqueue, which means the caller needs 600 * to handle waiting on the async flush for space to become available. 601 * We don't want to interrupt any push that is in progress, hence we only queue 602 * work if we set the pushing bit approriately. 603 * 604 * We do this unlocked - we only need to know whether there is anything in the 605 * AIL at the time we are called. We don't need to access the contents of 606 * any of the objects, so the lock is not needed. 607 */ 608 void 609 xfs_ail_push( 610 struct xfs_ail *ailp, 611 xfs_lsn_t threshold_lsn) 612 { 613 xfs_log_item_t *lip; 614 615 lip = xfs_ail_min(ailp); 616 if (!lip || XFS_FORCED_SHUTDOWN(ailp->ail_mount) || 617 XFS_LSN_CMP(threshold_lsn, ailp->ail_target) <= 0) 618 return; 619 620 /* 621 * Ensure that the new target is noticed in push code before it clears 622 * the XFS_AIL_PUSHING_BIT. 623 */ 624 smp_wmb(); 625 xfs_trans_ail_copy_lsn(ailp, &ailp->ail_target, &threshold_lsn); 626 smp_wmb(); 627 628 wake_up_process(ailp->ail_task); 629 } 630 631 /* 632 * Push out all items in the AIL immediately 633 */ 634 void 635 xfs_ail_push_all( 636 struct xfs_ail *ailp) 637 { 638 xfs_lsn_t threshold_lsn = xfs_ail_max_lsn(ailp); 639 640 if (threshold_lsn) 641 xfs_ail_push(ailp, threshold_lsn); 642 } 643 644 /* 645 * Push out all items in the AIL immediately and wait until the AIL is empty. 646 */ 647 void 648 xfs_ail_push_all_sync( 649 struct xfs_ail *ailp) 650 { 651 struct xfs_log_item *lip; 652 DEFINE_WAIT(wait); 653 654 spin_lock(&ailp->ail_lock); 655 while ((lip = xfs_ail_max(ailp)) != NULL) { 656 prepare_to_wait(&ailp->ail_empty, &wait, TASK_UNINTERRUPTIBLE); 657 ailp->ail_target = lip->li_lsn; 658 wake_up_process(ailp->ail_task); 659 spin_unlock(&ailp->ail_lock); 660 schedule(); 661 spin_lock(&ailp->ail_lock); 662 } 663 spin_unlock(&ailp->ail_lock); 664 665 finish_wait(&ailp->ail_empty, &wait); 666 } 667 668 /* 669 * xfs_trans_ail_update - bulk AIL insertion operation. 670 * 671 * @xfs_trans_ail_update takes an array of log items that all need to be 672 * positioned at the same LSN in the AIL. If an item is not in the AIL, it will 673 * be added. Otherwise, it will be repositioned by removing it and re-adding 674 * it to the AIL. If we move the first item in the AIL, update the log tail to 675 * match the new minimum LSN in the AIL. 676 * 677 * This function takes the AIL lock once to execute the update operations on 678 * all the items in the array, and as such should not be called with the AIL 679 * lock held. As a result, once we have the AIL lock, we need to check each log 680 * item LSN to confirm it needs to be moved forward in the AIL. 681 * 682 * To optimise the insert operation, we delete all the items from the AIL in 683 * the first pass, moving them into a temporary list, then splice the temporary 684 * list into the correct position in the AIL. This avoids needing to do an 685 * insert operation on every item. 686 * 687 * This function must be called with the AIL lock held. The lock is dropped 688 * before returning. 689 */ 690 void 691 xfs_trans_ail_update_bulk( 692 struct xfs_ail *ailp, 693 struct xfs_ail_cursor *cur, 694 struct xfs_log_item **log_items, 695 int nr_items, 696 xfs_lsn_t lsn) __releases(ailp->ail_lock) 697 { 698 xfs_log_item_t *mlip; 699 int mlip_changed = 0; 700 int i; 701 LIST_HEAD(tmp); 702 703 ASSERT(nr_items > 0); /* Not required, but true. */ 704 mlip = xfs_ail_min(ailp); 705 706 for (i = 0; i < nr_items; i++) { 707 struct xfs_log_item *lip = log_items[i]; 708 if (test_and_set_bit(XFS_LI_IN_AIL, &lip->li_flags)) { 709 /* check if we really need to move the item */ 710 if (XFS_LSN_CMP(lsn, lip->li_lsn) <= 0) 711 continue; 712 713 trace_xfs_ail_move(lip, lip->li_lsn, lsn); 714 xfs_ail_delete(ailp, lip); 715 if (mlip == lip) 716 mlip_changed = 1; 717 } else { 718 trace_xfs_ail_insert(lip, 0, lsn); 719 } 720 lip->li_lsn = lsn; 721 list_add(&lip->li_ail, &tmp); 722 } 723 724 if (!list_empty(&tmp)) 725 xfs_ail_splice(ailp, cur, &tmp, lsn); 726 727 if (mlip_changed) { 728 if (!XFS_FORCED_SHUTDOWN(ailp->ail_mount)) 729 xlog_assign_tail_lsn_locked(ailp->ail_mount); 730 spin_unlock(&ailp->ail_lock); 731 732 xfs_log_space_wake(ailp->ail_mount); 733 } else { 734 spin_unlock(&ailp->ail_lock); 735 } 736 } 737 738 bool 739 xfs_ail_delete_one( 740 struct xfs_ail *ailp, 741 struct xfs_log_item *lip) 742 { 743 struct xfs_log_item *mlip = xfs_ail_min(ailp); 744 745 trace_xfs_ail_delete(lip, mlip->li_lsn, lip->li_lsn); 746 xfs_ail_delete(ailp, lip); 747 xfs_clear_li_failed(lip); 748 clear_bit(XFS_LI_IN_AIL, &lip->li_flags); 749 lip->li_lsn = 0; 750 751 return mlip == lip; 752 } 753 754 /** 755 * Remove a log items from the AIL 756 * 757 * @xfs_trans_ail_delete_bulk takes an array of log items that all need to 758 * removed from the AIL. The caller is already holding the AIL lock, and done 759 * all the checks necessary to ensure the items passed in via @log_items are 760 * ready for deletion. This includes checking that the items are in the AIL. 761 * 762 * For each log item to be removed, unlink it from the AIL, clear the IN_AIL 763 * flag from the item and reset the item's lsn to 0. If we remove the first 764 * item in the AIL, update the log tail to match the new minimum LSN in the 765 * AIL. 766 * 767 * This function will not drop the AIL lock until all items are removed from 768 * the AIL to minimise the amount of lock traffic on the AIL. This does not 769 * greatly increase the AIL hold time, but does significantly reduce the amount 770 * of traffic on the lock, especially during IO completion. 771 * 772 * This function must be called with the AIL lock held. The lock is dropped 773 * before returning. 774 */ 775 void 776 xfs_trans_ail_delete( 777 struct xfs_ail *ailp, 778 struct xfs_log_item *lip, 779 int shutdown_type) __releases(ailp->ail_lock) 780 { 781 struct xfs_mount *mp = ailp->ail_mount; 782 bool mlip_changed; 783 784 if (!test_bit(XFS_LI_IN_AIL, &lip->li_flags)) { 785 spin_unlock(&ailp->ail_lock); 786 if (!XFS_FORCED_SHUTDOWN(mp)) { 787 xfs_alert_tag(mp, XFS_PTAG_AILDELETE, 788 "%s: attempting to delete a log item that is not in the AIL", 789 __func__); 790 xfs_force_shutdown(mp, shutdown_type); 791 } 792 return; 793 } 794 795 mlip_changed = xfs_ail_delete_one(ailp, lip); 796 if (mlip_changed) { 797 if (!XFS_FORCED_SHUTDOWN(mp)) 798 xlog_assign_tail_lsn_locked(mp); 799 if (list_empty(&ailp->ail_head)) 800 wake_up_all(&ailp->ail_empty); 801 } 802 803 spin_unlock(&ailp->ail_lock); 804 if (mlip_changed) 805 xfs_log_space_wake(ailp->ail_mount); 806 } 807 808 int 809 xfs_trans_ail_init( 810 xfs_mount_t *mp) 811 { 812 struct xfs_ail *ailp; 813 814 ailp = kmem_zalloc(sizeof(struct xfs_ail), KM_MAYFAIL); 815 if (!ailp) 816 return -ENOMEM; 817 818 ailp->ail_mount = mp; 819 INIT_LIST_HEAD(&ailp->ail_head); 820 INIT_LIST_HEAD(&ailp->ail_cursors); 821 spin_lock_init(&ailp->ail_lock); 822 INIT_LIST_HEAD(&ailp->ail_buf_list); 823 init_waitqueue_head(&ailp->ail_empty); 824 825 ailp->ail_task = kthread_run(xfsaild, ailp, "xfsaild/%s", 826 ailp->ail_mount->m_fsname); 827 if (IS_ERR(ailp->ail_task)) 828 goto out_free_ailp; 829 830 mp->m_ail = ailp; 831 return 0; 832 833 out_free_ailp: 834 kmem_free(ailp); 835 return -ENOMEM; 836 } 837 838 void 839 xfs_trans_ail_destroy( 840 xfs_mount_t *mp) 841 { 842 struct xfs_ail *ailp = mp->m_ail; 843 844 kthread_stop(ailp->ail_task); 845 kmem_free(ailp); 846 } 847