1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc. 4 * Copyright (c) 2008 Dave Chinner 5 * All Rights Reserved. 6 */ 7 #include "xfs.h" 8 #include "xfs_fs.h" 9 #include "xfs_shared.h" 10 #include "xfs_format.h" 11 #include "xfs_log_format.h" 12 #include "xfs_trans_resv.h" 13 #include "xfs_mount.h" 14 #include "xfs_trans.h" 15 #include "xfs_trans_priv.h" 16 #include "xfs_trace.h" 17 #include "xfs_errortag.h" 18 #include "xfs_error.h" 19 #include "xfs_log.h" 20 21 #ifdef DEBUG 22 /* 23 * Check that the list is sorted as it should be. 24 * 25 * Called with the ail lock held, but we don't want to assert fail with it 26 * held otherwise we'll lock everything up and won't be able to debug the 27 * cause. Hence we sample and check the state under the AIL lock and return if 28 * everything is fine, otherwise we drop the lock and run the ASSERT checks. 29 * Asserts may not be fatal, so pick the lock back up and continue onwards. 30 */ 31 STATIC void 32 xfs_ail_check( 33 struct xfs_ail *ailp, 34 struct xfs_log_item *lip) 35 __must_hold(&ailp->ail_lock) 36 { 37 struct xfs_log_item *prev_lip; 38 struct xfs_log_item *next_lip; 39 xfs_lsn_t prev_lsn = NULLCOMMITLSN; 40 xfs_lsn_t next_lsn = NULLCOMMITLSN; 41 xfs_lsn_t lsn; 42 bool in_ail; 43 44 45 if (list_empty(&ailp->ail_head)) 46 return; 47 48 /* 49 * Sample then check the next and previous entries are valid. 50 */ 51 in_ail = test_bit(XFS_LI_IN_AIL, &lip->li_flags); 52 prev_lip = list_entry(lip->li_ail.prev, struct xfs_log_item, li_ail); 53 if (&prev_lip->li_ail != &ailp->ail_head) 54 prev_lsn = prev_lip->li_lsn; 55 next_lip = list_entry(lip->li_ail.next, struct xfs_log_item, li_ail); 56 if (&next_lip->li_ail != &ailp->ail_head) 57 next_lsn = next_lip->li_lsn; 58 lsn = lip->li_lsn; 59 60 if (in_ail && 61 (prev_lsn == NULLCOMMITLSN || XFS_LSN_CMP(prev_lsn, lsn) <= 0) && 62 (next_lsn == NULLCOMMITLSN || XFS_LSN_CMP(next_lsn, lsn) >= 0)) 63 return; 64 65 spin_unlock(&ailp->ail_lock); 66 ASSERT(in_ail); 67 ASSERT(prev_lsn == NULLCOMMITLSN || XFS_LSN_CMP(prev_lsn, lsn) <= 0); 68 ASSERT(next_lsn == NULLCOMMITLSN || XFS_LSN_CMP(next_lsn, lsn) >= 0); 69 spin_lock(&ailp->ail_lock); 70 } 71 #else /* !DEBUG */ 72 #define xfs_ail_check(a,l) 73 #endif /* DEBUG */ 74 75 /* 76 * Return a pointer to the last item in the AIL. If the AIL is empty, then 77 * return NULL. 78 */ 79 static struct xfs_log_item * 80 xfs_ail_max( 81 struct xfs_ail *ailp) 82 { 83 if (list_empty(&ailp->ail_head)) 84 return NULL; 85 86 return list_entry(ailp->ail_head.prev, struct xfs_log_item, li_ail); 87 } 88 89 /* 90 * Return a pointer to the item which follows the given item in the AIL. If 91 * the given item is the last item in the list, then return NULL. 92 */ 93 static struct xfs_log_item * 94 xfs_ail_next( 95 struct xfs_ail *ailp, 96 struct xfs_log_item *lip) 97 { 98 if (lip->li_ail.next == &ailp->ail_head) 99 return NULL; 100 101 return list_first_entry(&lip->li_ail, struct xfs_log_item, li_ail); 102 } 103 104 /* 105 * This is called by the log manager code to determine the LSN of the tail of 106 * the log. This is exactly the LSN of the first item in the AIL. If the AIL 107 * is empty, then this function returns 0. 108 * 109 * We need the AIL lock in order to get a coherent read of the lsn of the last 110 * item in the AIL. 111 */ 112 xfs_lsn_t 113 xfs_ail_min_lsn( 114 struct xfs_ail *ailp) 115 { 116 xfs_lsn_t lsn = 0; 117 struct xfs_log_item *lip; 118 119 spin_lock(&ailp->ail_lock); 120 lip = xfs_ail_min(ailp); 121 if (lip) 122 lsn = lip->li_lsn; 123 spin_unlock(&ailp->ail_lock); 124 125 return lsn; 126 } 127 128 /* 129 * Return the maximum lsn held in the AIL, or zero if the AIL is empty. 130 */ 131 static xfs_lsn_t 132 xfs_ail_max_lsn( 133 struct xfs_ail *ailp) 134 { 135 xfs_lsn_t lsn = 0; 136 struct xfs_log_item *lip; 137 138 spin_lock(&ailp->ail_lock); 139 lip = xfs_ail_max(ailp); 140 if (lip) 141 lsn = lip->li_lsn; 142 spin_unlock(&ailp->ail_lock); 143 144 return lsn; 145 } 146 147 /* 148 * The cursor keeps track of where our current traversal is up to by tracking 149 * the next item in the list for us. However, for this to be safe, removing an 150 * object from the AIL needs to invalidate any cursor that points to it. hence 151 * the traversal cursor needs to be linked to the struct xfs_ail so that 152 * deletion can search all the active cursors for invalidation. 153 */ 154 STATIC void 155 xfs_trans_ail_cursor_init( 156 struct xfs_ail *ailp, 157 struct xfs_ail_cursor *cur) 158 { 159 cur->item = NULL; 160 list_add_tail(&cur->list, &ailp->ail_cursors); 161 } 162 163 /* 164 * Get the next item in the traversal and advance the cursor. If the cursor 165 * was invalidated (indicated by a lip of 1), restart the traversal. 166 */ 167 struct xfs_log_item * 168 xfs_trans_ail_cursor_next( 169 struct xfs_ail *ailp, 170 struct xfs_ail_cursor *cur) 171 { 172 struct xfs_log_item *lip = cur->item; 173 174 if ((uintptr_t)lip & 1) 175 lip = xfs_ail_min(ailp); 176 if (lip) 177 cur->item = xfs_ail_next(ailp, lip); 178 return lip; 179 } 180 181 /* 182 * When the traversal is complete, we need to remove the cursor from the list 183 * of traversing cursors. 184 */ 185 void 186 xfs_trans_ail_cursor_done( 187 struct xfs_ail_cursor *cur) 188 { 189 cur->item = NULL; 190 list_del_init(&cur->list); 191 } 192 193 /* 194 * Invalidate any cursor that is pointing to this item. This is called when an 195 * item is removed from the AIL. Any cursor pointing to this object is now 196 * invalid and the traversal needs to be terminated so it doesn't reference a 197 * freed object. We set the low bit of the cursor item pointer so we can 198 * distinguish between an invalidation and the end of the list when getting the 199 * next item from the cursor. 200 */ 201 STATIC void 202 xfs_trans_ail_cursor_clear( 203 struct xfs_ail *ailp, 204 struct xfs_log_item *lip) 205 { 206 struct xfs_ail_cursor *cur; 207 208 list_for_each_entry(cur, &ailp->ail_cursors, list) { 209 if (cur->item == lip) 210 cur->item = (struct xfs_log_item *) 211 ((uintptr_t)cur->item | 1); 212 } 213 } 214 215 /* 216 * Find the first item in the AIL with the given @lsn by searching in ascending 217 * LSN order and initialise the cursor to point to the next item for a 218 * ascending traversal. Pass a @lsn of zero to initialise the cursor to the 219 * first item in the AIL. Returns NULL if the list is empty. 220 */ 221 struct xfs_log_item * 222 xfs_trans_ail_cursor_first( 223 struct xfs_ail *ailp, 224 struct xfs_ail_cursor *cur, 225 xfs_lsn_t lsn) 226 { 227 struct xfs_log_item *lip; 228 229 xfs_trans_ail_cursor_init(ailp, cur); 230 231 if (lsn == 0) { 232 lip = xfs_ail_min(ailp); 233 goto out; 234 } 235 236 list_for_each_entry(lip, &ailp->ail_head, li_ail) { 237 if (XFS_LSN_CMP(lip->li_lsn, lsn) >= 0) 238 goto out; 239 } 240 return NULL; 241 242 out: 243 if (lip) 244 cur->item = xfs_ail_next(ailp, lip); 245 return lip; 246 } 247 248 static struct xfs_log_item * 249 __xfs_trans_ail_cursor_last( 250 struct xfs_ail *ailp, 251 xfs_lsn_t lsn) 252 { 253 struct xfs_log_item *lip; 254 255 list_for_each_entry_reverse(lip, &ailp->ail_head, li_ail) { 256 if (XFS_LSN_CMP(lip->li_lsn, lsn) <= 0) 257 return lip; 258 } 259 return NULL; 260 } 261 262 /* 263 * Find the last item in the AIL with the given @lsn by searching in descending 264 * LSN order and initialise the cursor to point to that item. If there is no 265 * item with the value of @lsn, then it sets the cursor to the last item with an 266 * LSN lower than @lsn. Returns NULL if the list is empty. 267 */ 268 struct xfs_log_item * 269 xfs_trans_ail_cursor_last( 270 struct xfs_ail *ailp, 271 struct xfs_ail_cursor *cur, 272 xfs_lsn_t lsn) 273 { 274 xfs_trans_ail_cursor_init(ailp, cur); 275 cur->item = __xfs_trans_ail_cursor_last(ailp, lsn); 276 return cur->item; 277 } 278 279 /* 280 * Splice the log item list into the AIL at the given LSN. We splice to the 281 * tail of the given LSN to maintain insert order for push traversals. The 282 * cursor is optional, allowing repeated updates to the same LSN to avoid 283 * repeated traversals. This should not be called with an empty list. 284 */ 285 static void 286 xfs_ail_splice( 287 struct xfs_ail *ailp, 288 struct xfs_ail_cursor *cur, 289 struct list_head *list, 290 xfs_lsn_t lsn) 291 { 292 struct xfs_log_item *lip; 293 294 ASSERT(!list_empty(list)); 295 296 /* 297 * Use the cursor to determine the insertion point if one is 298 * provided. If not, or if the one we got is not valid, 299 * find the place in the AIL where the items belong. 300 */ 301 lip = cur ? cur->item : NULL; 302 if (!lip || (uintptr_t)lip & 1) 303 lip = __xfs_trans_ail_cursor_last(ailp, lsn); 304 305 /* 306 * If a cursor is provided, we know we're processing the AIL 307 * in lsn order, and future items to be spliced in will 308 * follow the last one being inserted now. Update the 309 * cursor to point to that last item, now while we have a 310 * reliable pointer to it. 311 */ 312 if (cur) 313 cur->item = list_entry(list->prev, struct xfs_log_item, li_ail); 314 315 /* 316 * Finally perform the splice. Unless the AIL was empty, 317 * lip points to the item in the AIL _after_ which the new 318 * items should go. If lip is null the AIL was empty, so 319 * the new items go at the head of the AIL. 320 */ 321 if (lip) 322 list_splice(list, &lip->li_ail); 323 else 324 list_splice(list, &ailp->ail_head); 325 } 326 327 /* 328 * Delete the given item from the AIL. Return a pointer to the item. 329 */ 330 static void 331 xfs_ail_delete( 332 struct xfs_ail *ailp, 333 struct xfs_log_item *lip) 334 { 335 xfs_ail_check(ailp, lip); 336 list_del(&lip->li_ail); 337 xfs_trans_ail_cursor_clear(ailp, lip); 338 } 339 340 static inline uint 341 xfsaild_push_item( 342 struct xfs_ail *ailp, 343 struct xfs_log_item *lip) 344 { 345 /* 346 * If log item pinning is enabled, skip the push and track the item as 347 * pinned. This can help induce head-behind-tail conditions. 348 */ 349 if (XFS_TEST_ERROR(false, ailp->ail_mount, XFS_ERRTAG_LOG_ITEM_PIN)) 350 return XFS_ITEM_PINNED; 351 352 /* 353 * Consider the item pinned if a push callback is not defined so the 354 * caller will force the log. This should only happen for intent items 355 * as they are unpinned once the associated done item is committed to 356 * the on-disk log. 357 */ 358 if (!lip->li_ops->iop_push) 359 return XFS_ITEM_PINNED; 360 return lip->li_ops->iop_push(lip, &ailp->ail_buf_list); 361 } 362 363 static long 364 xfsaild_push( 365 struct xfs_ail *ailp) 366 { 367 xfs_mount_t *mp = ailp->ail_mount; 368 struct xfs_ail_cursor cur; 369 struct xfs_log_item *lip; 370 xfs_lsn_t lsn; 371 xfs_lsn_t target; 372 long tout; 373 int stuck = 0; 374 int flushing = 0; 375 int count = 0; 376 377 /* 378 * If we encountered pinned items or did not finish writing out all 379 * buffers the last time we ran, force the log first and wait for it 380 * before pushing again. 381 */ 382 if (ailp->ail_log_flush && ailp->ail_last_pushed_lsn == 0 && 383 (!list_empty_careful(&ailp->ail_buf_list) || 384 xfs_ail_min_lsn(ailp))) { 385 ailp->ail_log_flush = 0; 386 387 XFS_STATS_INC(mp, xs_push_ail_flush); 388 xfs_log_force(mp, XFS_LOG_SYNC); 389 } 390 391 spin_lock(&ailp->ail_lock); 392 393 /* barrier matches the ail_target update in xfs_ail_push() */ 394 smp_rmb(); 395 target = ailp->ail_target; 396 ailp->ail_target_prev = target; 397 398 lip = xfs_trans_ail_cursor_first(ailp, &cur, ailp->ail_last_pushed_lsn); 399 if (!lip) { 400 /* 401 * If the AIL is empty or our push has reached the end we are 402 * done now. 403 */ 404 xfs_trans_ail_cursor_done(&cur); 405 spin_unlock(&ailp->ail_lock); 406 goto out_done; 407 } 408 409 XFS_STATS_INC(mp, xs_push_ail); 410 411 lsn = lip->li_lsn; 412 while ((XFS_LSN_CMP(lip->li_lsn, target) <= 0)) { 413 int lock_result; 414 415 /* 416 * Note that iop_push may unlock and reacquire the AIL lock. We 417 * rely on the AIL cursor implementation to be able to deal with 418 * the dropped lock. 419 */ 420 lock_result = xfsaild_push_item(ailp, lip); 421 switch (lock_result) { 422 case XFS_ITEM_SUCCESS: 423 XFS_STATS_INC(mp, xs_push_ail_success); 424 trace_xfs_ail_push(lip); 425 426 ailp->ail_last_pushed_lsn = lsn; 427 break; 428 429 case XFS_ITEM_FLUSHING: 430 /* 431 * The item or its backing buffer is already being 432 * flushed. The typical reason for that is that an 433 * inode buffer is locked because we already pushed the 434 * updates to it as part of inode clustering. 435 * 436 * We do not want to to stop flushing just because lots 437 * of items are already being flushed, but we need to 438 * re-try the flushing relatively soon if most of the 439 * AIL is being flushed. 440 */ 441 XFS_STATS_INC(mp, xs_push_ail_flushing); 442 trace_xfs_ail_flushing(lip); 443 444 flushing++; 445 ailp->ail_last_pushed_lsn = lsn; 446 break; 447 448 case XFS_ITEM_PINNED: 449 XFS_STATS_INC(mp, xs_push_ail_pinned); 450 trace_xfs_ail_pinned(lip); 451 452 stuck++; 453 ailp->ail_log_flush++; 454 break; 455 case XFS_ITEM_LOCKED: 456 XFS_STATS_INC(mp, xs_push_ail_locked); 457 trace_xfs_ail_locked(lip); 458 459 stuck++; 460 break; 461 default: 462 ASSERT(0); 463 break; 464 } 465 466 count++; 467 468 /* 469 * Are there too many items we can't do anything with? 470 * 471 * If we we are skipping too many items because we can't flush 472 * them or they are already being flushed, we back off and 473 * given them time to complete whatever operation is being 474 * done. i.e. remove pressure from the AIL while we can't make 475 * progress so traversals don't slow down further inserts and 476 * removals to/from the AIL. 477 * 478 * The value of 100 is an arbitrary magic number based on 479 * observation. 480 */ 481 if (stuck > 100) 482 break; 483 484 lip = xfs_trans_ail_cursor_next(ailp, &cur); 485 if (lip == NULL) 486 break; 487 lsn = lip->li_lsn; 488 } 489 xfs_trans_ail_cursor_done(&cur); 490 spin_unlock(&ailp->ail_lock); 491 492 if (xfs_buf_delwri_submit_nowait(&ailp->ail_buf_list)) 493 ailp->ail_log_flush++; 494 495 if (!count || XFS_LSN_CMP(lsn, target) >= 0) { 496 out_done: 497 /* 498 * We reached the target or the AIL is empty, so wait a bit 499 * longer for I/O to complete and remove pushed items from the 500 * AIL before we start the next scan from the start of the AIL. 501 */ 502 tout = 50; 503 ailp->ail_last_pushed_lsn = 0; 504 } else if (((stuck + flushing) * 100) / count > 90) { 505 /* 506 * Either there is a lot of contention on the AIL or we are 507 * stuck due to operations in progress. "Stuck" in this case 508 * is defined as >90% of the items we tried to push were stuck. 509 * 510 * Backoff a bit more to allow some I/O to complete before 511 * restarting from the start of the AIL. This prevents us from 512 * spinning on the same items, and if they are pinned will all 513 * the restart to issue a log force to unpin the stuck items. 514 */ 515 tout = 20; 516 ailp->ail_last_pushed_lsn = 0; 517 } else { 518 /* 519 * Assume we have more work to do in a short while. 520 */ 521 tout = 10; 522 } 523 524 return tout; 525 } 526 527 static int 528 xfsaild( 529 void *data) 530 { 531 struct xfs_ail *ailp = data; 532 long tout = 0; /* milliseconds */ 533 unsigned int noreclaim_flag; 534 535 noreclaim_flag = memalloc_noreclaim_save(); 536 set_freezable(); 537 538 while (1) { 539 if (tout && tout <= 20) 540 set_current_state(TASK_KILLABLE); 541 else 542 set_current_state(TASK_INTERRUPTIBLE); 543 544 /* 545 * Check kthread_should_stop() after we set the task state to 546 * guarantee that we either see the stop bit and exit or the 547 * task state is reset to runnable such that it's not scheduled 548 * out indefinitely and detects the stop bit at next iteration. 549 * A memory barrier is included in above task state set to 550 * serialize again kthread_stop(). 551 */ 552 if (kthread_should_stop()) { 553 __set_current_state(TASK_RUNNING); 554 555 /* 556 * The caller forces out the AIL before stopping the 557 * thread in the common case, which means the delwri 558 * queue is drained. In the shutdown case, the queue may 559 * still hold relogged buffers that haven't been 560 * submitted because they were pinned since added to the 561 * queue. 562 * 563 * Log I/O error processing stales the underlying buffer 564 * and clears the delwri state, expecting the buf to be 565 * removed on the next submission attempt. That won't 566 * happen if we're shutting down, so this is the last 567 * opportunity to release such buffers from the queue. 568 */ 569 ASSERT(list_empty(&ailp->ail_buf_list) || 570 XFS_FORCED_SHUTDOWN(ailp->ail_mount)); 571 xfs_buf_delwri_cancel(&ailp->ail_buf_list); 572 break; 573 } 574 575 spin_lock(&ailp->ail_lock); 576 577 /* 578 * Idle if the AIL is empty and we are not racing with a target 579 * update. We check the AIL after we set the task to a sleep 580 * state to guarantee that we either catch an ail_target update 581 * or that a wake_up resets the state to TASK_RUNNING. 582 * Otherwise, we run the risk of sleeping indefinitely. 583 * 584 * The barrier matches the ail_target update in xfs_ail_push(). 585 */ 586 smp_rmb(); 587 if (!xfs_ail_min(ailp) && 588 ailp->ail_target == ailp->ail_target_prev) { 589 spin_unlock(&ailp->ail_lock); 590 freezable_schedule(); 591 tout = 0; 592 continue; 593 } 594 spin_unlock(&ailp->ail_lock); 595 596 if (tout) 597 freezable_schedule_timeout(msecs_to_jiffies(tout)); 598 599 __set_current_state(TASK_RUNNING); 600 601 try_to_freeze(); 602 603 tout = xfsaild_push(ailp); 604 } 605 606 memalloc_noreclaim_restore(noreclaim_flag); 607 return 0; 608 } 609 610 /* 611 * This routine is called to move the tail of the AIL forward. It does this by 612 * trying to flush items in the AIL whose lsns are below the given 613 * threshold_lsn. 614 * 615 * The push is run asynchronously in a workqueue, which means the caller needs 616 * to handle waiting on the async flush for space to become available. 617 * We don't want to interrupt any push that is in progress, hence we only queue 618 * work if we set the pushing bit appropriately. 619 * 620 * We do this unlocked - we only need to know whether there is anything in the 621 * AIL at the time we are called. We don't need to access the contents of 622 * any of the objects, so the lock is not needed. 623 */ 624 void 625 xfs_ail_push( 626 struct xfs_ail *ailp, 627 xfs_lsn_t threshold_lsn) 628 { 629 struct xfs_log_item *lip; 630 631 lip = xfs_ail_min(ailp); 632 if (!lip || XFS_FORCED_SHUTDOWN(ailp->ail_mount) || 633 XFS_LSN_CMP(threshold_lsn, ailp->ail_target) <= 0) 634 return; 635 636 /* 637 * Ensure that the new target is noticed in push code before it clears 638 * the XFS_AIL_PUSHING_BIT. 639 */ 640 smp_wmb(); 641 xfs_trans_ail_copy_lsn(ailp, &ailp->ail_target, &threshold_lsn); 642 smp_wmb(); 643 644 wake_up_process(ailp->ail_task); 645 } 646 647 /* 648 * Push out all items in the AIL immediately 649 */ 650 void 651 xfs_ail_push_all( 652 struct xfs_ail *ailp) 653 { 654 xfs_lsn_t threshold_lsn = xfs_ail_max_lsn(ailp); 655 656 if (threshold_lsn) 657 xfs_ail_push(ailp, threshold_lsn); 658 } 659 660 /* 661 * Push out all items in the AIL immediately and wait until the AIL is empty. 662 */ 663 void 664 xfs_ail_push_all_sync( 665 struct xfs_ail *ailp) 666 { 667 struct xfs_log_item *lip; 668 DEFINE_WAIT(wait); 669 670 spin_lock(&ailp->ail_lock); 671 while ((lip = xfs_ail_max(ailp)) != NULL) { 672 prepare_to_wait(&ailp->ail_empty, &wait, TASK_UNINTERRUPTIBLE); 673 ailp->ail_target = lip->li_lsn; 674 wake_up_process(ailp->ail_task); 675 spin_unlock(&ailp->ail_lock); 676 schedule(); 677 spin_lock(&ailp->ail_lock); 678 } 679 spin_unlock(&ailp->ail_lock); 680 681 finish_wait(&ailp->ail_empty, &wait); 682 } 683 684 /* 685 * xfs_trans_ail_update - bulk AIL insertion operation. 686 * 687 * @xfs_trans_ail_update takes an array of log items that all need to be 688 * positioned at the same LSN in the AIL. If an item is not in the AIL, it will 689 * be added. Otherwise, it will be repositioned by removing it and re-adding 690 * it to the AIL. If we move the first item in the AIL, update the log tail to 691 * match the new minimum LSN in the AIL. 692 * 693 * This function takes the AIL lock once to execute the update operations on 694 * all the items in the array, and as such should not be called with the AIL 695 * lock held. As a result, once we have the AIL lock, we need to check each log 696 * item LSN to confirm it needs to be moved forward in the AIL. 697 * 698 * To optimise the insert operation, we delete all the items from the AIL in 699 * the first pass, moving them into a temporary list, then splice the temporary 700 * list into the correct position in the AIL. This avoids needing to do an 701 * insert operation on every item. 702 * 703 * This function must be called with the AIL lock held. The lock is dropped 704 * before returning. 705 */ 706 void 707 xfs_trans_ail_update_bulk( 708 struct xfs_ail *ailp, 709 struct xfs_ail_cursor *cur, 710 struct xfs_log_item **log_items, 711 int nr_items, 712 xfs_lsn_t lsn) __releases(ailp->ail_lock) 713 { 714 struct xfs_log_item *mlip; 715 int mlip_changed = 0; 716 int i; 717 LIST_HEAD(tmp); 718 719 ASSERT(nr_items > 0); /* Not required, but true. */ 720 mlip = xfs_ail_min(ailp); 721 722 for (i = 0; i < nr_items; i++) { 723 struct xfs_log_item *lip = log_items[i]; 724 if (test_and_set_bit(XFS_LI_IN_AIL, &lip->li_flags)) { 725 /* check if we really need to move the item */ 726 if (XFS_LSN_CMP(lsn, lip->li_lsn) <= 0) 727 continue; 728 729 trace_xfs_ail_move(lip, lip->li_lsn, lsn); 730 xfs_ail_delete(ailp, lip); 731 if (mlip == lip) 732 mlip_changed = 1; 733 } else { 734 trace_xfs_ail_insert(lip, 0, lsn); 735 } 736 lip->li_lsn = lsn; 737 list_add(&lip->li_ail, &tmp); 738 } 739 740 if (!list_empty(&tmp)) 741 xfs_ail_splice(ailp, cur, &tmp, lsn); 742 743 if (mlip_changed) { 744 if (!XFS_FORCED_SHUTDOWN(ailp->ail_mount)) 745 xlog_assign_tail_lsn_locked(ailp->ail_mount); 746 spin_unlock(&ailp->ail_lock); 747 748 xfs_log_space_wake(ailp->ail_mount); 749 } else { 750 spin_unlock(&ailp->ail_lock); 751 } 752 } 753 754 bool 755 xfs_ail_delete_one( 756 struct xfs_ail *ailp, 757 struct xfs_log_item *lip) 758 { 759 struct xfs_log_item *mlip = xfs_ail_min(ailp); 760 761 trace_xfs_ail_delete(lip, mlip->li_lsn, lip->li_lsn); 762 xfs_ail_delete(ailp, lip); 763 xfs_clear_li_failed(lip); 764 clear_bit(XFS_LI_IN_AIL, &lip->li_flags); 765 lip->li_lsn = 0; 766 767 return mlip == lip; 768 } 769 770 /** 771 * Remove a log items from the AIL 772 * 773 * @xfs_trans_ail_delete_bulk takes an array of log items that all need to 774 * removed from the AIL. The caller is already holding the AIL lock, and done 775 * all the checks necessary to ensure the items passed in via @log_items are 776 * ready for deletion. This includes checking that the items are in the AIL. 777 * 778 * For each log item to be removed, unlink it from the AIL, clear the IN_AIL 779 * flag from the item and reset the item's lsn to 0. If we remove the first 780 * item in the AIL, update the log tail to match the new minimum LSN in the 781 * AIL. 782 * 783 * This function will not drop the AIL lock until all items are removed from 784 * the AIL to minimise the amount of lock traffic on the AIL. This does not 785 * greatly increase the AIL hold time, but does significantly reduce the amount 786 * of traffic on the lock, especially during IO completion. 787 * 788 * This function must be called with the AIL lock held. The lock is dropped 789 * before returning. 790 */ 791 void 792 xfs_trans_ail_delete( 793 struct xfs_ail *ailp, 794 struct xfs_log_item *lip, 795 int shutdown_type) __releases(ailp->ail_lock) 796 { 797 struct xfs_mount *mp = ailp->ail_mount; 798 bool mlip_changed; 799 800 if (!test_bit(XFS_LI_IN_AIL, &lip->li_flags)) { 801 spin_unlock(&ailp->ail_lock); 802 if (!XFS_FORCED_SHUTDOWN(mp)) { 803 xfs_alert_tag(mp, XFS_PTAG_AILDELETE, 804 "%s: attempting to delete a log item that is not in the AIL", 805 __func__); 806 xfs_force_shutdown(mp, shutdown_type); 807 } 808 return; 809 } 810 811 mlip_changed = xfs_ail_delete_one(ailp, lip); 812 if (mlip_changed) { 813 if (!XFS_FORCED_SHUTDOWN(mp)) 814 xlog_assign_tail_lsn_locked(mp); 815 if (list_empty(&ailp->ail_head)) 816 wake_up_all(&ailp->ail_empty); 817 } 818 819 spin_unlock(&ailp->ail_lock); 820 if (mlip_changed) 821 xfs_log_space_wake(ailp->ail_mount); 822 } 823 824 int 825 xfs_trans_ail_init( 826 xfs_mount_t *mp) 827 { 828 struct xfs_ail *ailp; 829 830 ailp = kmem_zalloc(sizeof(struct xfs_ail), KM_MAYFAIL); 831 if (!ailp) 832 return -ENOMEM; 833 834 ailp->ail_mount = mp; 835 INIT_LIST_HEAD(&ailp->ail_head); 836 INIT_LIST_HEAD(&ailp->ail_cursors); 837 spin_lock_init(&ailp->ail_lock); 838 INIT_LIST_HEAD(&ailp->ail_buf_list); 839 init_waitqueue_head(&ailp->ail_empty); 840 841 ailp->ail_task = kthread_run(xfsaild, ailp, "xfsaild/%s", 842 ailp->ail_mount->m_super->s_id); 843 if (IS_ERR(ailp->ail_task)) 844 goto out_free_ailp; 845 846 mp->m_ail = ailp; 847 return 0; 848 849 out_free_ailp: 850 kmem_free(ailp); 851 return -ENOMEM; 852 } 853 854 void 855 xfs_trans_ail_destroy( 856 xfs_mount_t *mp) 857 { 858 struct xfs_ail *ailp = mp->m_ail; 859 860 kthread_stop(ailp->ail_task); 861 kmem_free(ailp); 862 } 863