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