blob: 2d3c297259c252bd17e268fc8ca7c05c3691d468 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Nathan Scott7b718762005-11-02 14:58:39 +11002 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
3 * All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 *
Nathan Scott7b718762005-11-02 14:58:39 +11005 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * published by the Free Software Foundation.
8 *
Nathan Scott7b718762005-11-02 14:58:39 +11009 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 *
Nathan Scott7b718762005-11-02 14:58:39 +110014 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Linus Torvalds1da177e2005-04-16 15:20:36 -070017 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include "xfs.h"
Nathan Scotta844f452005-11-02 14:38:42 +110019#include "xfs_fs.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include "xfs_types.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include "xfs_log.h"
Nathan Scotta844f452005-11-02 14:38:42 +110022#include "xfs_inum.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include "xfs_trans.h"
24#include "xfs_sb.h"
David Chinnerda353b02007-08-28 14:00:13 +100025#include "xfs_ag.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include "xfs_dmapi.h"
27#include "xfs_mount.h"
28#include "xfs_trans_priv.h"
29#include "xfs_error.h"
30
31STATIC void xfs_ail_insert(xfs_ail_entry_t *, xfs_log_item_t *);
32STATIC xfs_log_item_t * xfs_ail_delete(xfs_ail_entry_t *, xfs_log_item_t *);
33STATIC xfs_log_item_t * xfs_ail_min(xfs_ail_entry_t *);
34STATIC xfs_log_item_t * xfs_ail_next(xfs_ail_entry_t *, xfs_log_item_t *);
35
36#ifdef DEBUG
37STATIC void xfs_ail_check(xfs_ail_entry_t *);
38#else
39#define xfs_ail_check(a)
40#endif /* DEBUG */
41
42
43/*
44 * This is called by the log manager code to determine the LSN
45 * of the tail of the log. This is exactly the LSN of the first
46 * item in the AIL. If the AIL is empty, then this function
47 * returns 0.
48 *
49 * We need the AIL lock in order to get a coherent read of the
50 * lsn of the last item in the AIL.
51 */
52xfs_lsn_t
53xfs_trans_tail_ail(
54 xfs_mount_t *mp)
55{
56 xfs_lsn_t lsn;
57 xfs_log_item_t *lip;
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Donald Douwsma287f3da2007-10-11 17:36:05 +100059 spin_lock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070060 lip = xfs_ail_min(&(mp->m_ail));
61 if (lip == NULL) {
62 lsn = (xfs_lsn_t)0;
63 } else {
64 lsn = lip->li_lsn;
65 }
Donald Douwsma287f3da2007-10-11 17:36:05 +100066 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
68 return lsn;
69}
70
71/*
72 * xfs_trans_push_ail
73 *
74 * This routine is called to move the tail of the AIL
75 * forward. It does this by trying to flush items in the AIL
76 * whose lsns are below the given threshold_lsn.
77 *
78 * The routine returns the lsn of the tail of the log.
79 */
80xfs_lsn_t
81xfs_trans_push_ail(
82 xfs_mount_t *mp,
83 xfs_lsn_t threshold_lsn)
84{
85 xfs_lsn_t lsn;
86 xfs_log_item_t *lip;
87 int gen;
88 int restarts;
89 int lock_result;
90 int flush_log;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091
Vlad Apostolov7666ab52007-02-10 18:35:52 +110092#define XFS_TRANS_PUSH_AIL_RESTARTS 1000
Linus Torvalds1da177e2005-04-16 15:20:36 -070093
Donald Douwsma287f3da2007-10-11 17:36:05 +100094 spin_lock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 lip = xfs_trans_first_ail(mp, &gen);
96 if (lip == NULL || XFS_FORCED_SHUTDOWN(mp)) {
97 /*
98 * Just return if the AIL is empty.
99 */
Donald Douwsma287f3da2007-10-11 17:36:05 +1000100 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 return (xfs_lsn_t)0;
102 }
103
104 XFS_STATS_INC(xs_push_ail);
105
106 /*
107 * While the item we are looking at is below the given threshold
108 * try to flush it out. Make sure to limit the number of times
109 * we allow xfs_trans_next_ail() to restart scanning from the
110 * beginning of the list. We'd like not to stop until we've at least
111 * tried to push on everything in the AIL with an LSN less than
112 * the given threshold. However, we may give up before that if
Donald Douwsma287f3da2007-10-11 17:36:05 +1000113 * we realize that we've been holding the AIL lock for 'too long',
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 * blocking interrupts. Currently, too long is < 500us roughly.
115 */
116 flush_log = 0;
117 restarts = 0;
118 while (((restarts < XFS_TRANS_PUSH_AIL_RESTARTS) &&
119 (XFS_LSN_CMP(lip->li_lsn, threshold_lsn) < 0))) {
120 /*
121 * If we can lock the item without sleeping, unlock
122 * the AIL lock and flush the item. Then re-grab the
123 * AIL lock so we can look for the next item on the
124 * AIL. Since we unlock the AIL while we flush the
125 * item, the next routine may start over again at the
126 * the beginning of the list if anything has changed.
127 * That is what the generation count is for.
128 *
129 * If we can't lock the item, either its holder will flush
130 * it or it is already being flushed or it is being relogged.
131 * In any of these case it is being taken care of and we
132 * can just skip to the next item in the list.
133 */
134 lock_result = IOP_TRYLOCK(lip);
135 switch (lock_result) {
136 case XFS_ITEM_SUCCESS:
Donald Douwsma287f3da2007-10-11 17:36:05 +1000137 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 XFS_STATS_INC(xs_push_ail_success);
139 IOP_PUSH(lip);
Donald Douwsma287f3da2007-10-11 17:36:05 +1000140 spin_lock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 break;
142
143 case XFS_ITEM_PUSHBUF:
Donald Douwsma287f3da2007-10-11 17:36:05 +1000144 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145 XFS_STATS_INC(xs_push_ail_pushbuf);
146#ifdef XFSRACEDEBUG
147 delay_for_intr();
148 delay(300);
149#endif
150 ASSERT(lip->li_ops->iop_pushbuf);
151 ASSERT(lip);
152 IOP_PUSHBUF(lip);
Donald Douwsma287f3da2007-10-11 17:36:05 +1000153 spin_lock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 break;
155
156 case XFS_ITEM_PINNED:
157 XFS_STATS_INC(xs_push_ail_pinned);
158 flush_log = 1;
159 break;
160
161 case XFS_ITEM_LOCKED:
162 XFS_STATS_INC(xs_push_ail_locked);
163 break;
164
165 case XFS_ITEM_FLUSHING:
166 XFS_STATS_INC(xs_push_ail_flushing);
167 break;
168
169 default:
170 ASSERT(0);
171 break;
172 }
173
174 lip = xfs_trans_next_ail(mp, lip, &gen, &restarts);
175 if (lip == NULL) {
176 break;
177 }
178 if (XFS_FORCED_SHUTDOWN(mp)) {
179 /*
180 * Just return if we shut down during the last try.
181 */
Donald Douwsma287f3da2007-10-11 17:36:05 +1000182 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183 return (xfs_lsn_t)0;
184 }
185
186 }
187
188 if (flush_log) {
189 /*
190 * If something we need to push out was pinned, then
191 * push out the log so it will become unpinned and
192 * move forward in the AIL.
193 */
Donald Douwsma287f3da2007-10-11 17:36:05 +1000194 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 XFS_STATS_INC(xs_push_ail_flush);
196 xfs_log_force(mp, (xfs_lsn_t)0, XFS_LOG_FORCE);
Donald Douwsma287f3da2007-10-11 17:36:05 +1000197 spin_lock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198 }
199
200 lip = xfs_ail_min(&(mp->m_ail));
201 if (lip == NULL) {
202 lsn = (xfs_lsn_t)0;
203 } else {
204 lsn = lip->li_lsn;
205 }
206
Donald Douwsma287f3da2007-10-11 17:36:05 +1000207 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 return lsn;
209} /* xfs_trans_push_ail */
210
211
212/*
213 * This is to be called when an item is unlocked that may have
214 * been in the AIL. It will wake up the first member of the AIL
215 * wait list if this item's unlocking might allow it to progress.
216 * If the item is in the AIL, then we need to get the AIL lock
217 * while doing our checking so we don't race with someone going
218 * to sleep waiting for this event in xfs_trans_push_ail().
219 */
220void
221xfs_trans_unlocked_item(
222 xfs_mount_t *mp,
223 xfs_log_item_t *lip)
224{
225 xfs_log_item_t *min_lip;
226
227 /*
228 * If we're forcibly shutting down, we may have
229 * unlocked log items arbitrarily. The last thing
230 * we want to do is to move the tail of the log
231 * over some potentially valid data.
232 */
233 if (!(lip->li_flags & XFS_LI_IN_AIL) ||
234 XFS_FORCED_SHUTDOWN(mp)) {
235 return;
236 }
237
238 /*
239 * This is the one case where we can call into xfs_ail_min()
240 * without holding the AIL lock because we only care about the
241 * case where we are at the tail of the AIL. If the object isn't
242 * at the tail, it doesn't matter what result we get back. This
243 * is slightly racy because since we were just unlocked, we could
244 * go to sleep between the call to xfs_ail_min and the call to
245 * xfs_log_move_tail, have someone else lock us, commit to us disk,
246 * move us out of the tail of the AIL, and then we wake up. However,
247 * the call to xfs_log_move_tail() doesn't do anything if there's
248 * not enough free space to wake people up so we're safe calling it.
249 */
250 min_lip = xfs_ail_min(&mp->m_ail);
251
252 if (min_lip == lip)
253 xfs_log_move_tail(mp, 1);
254} /* xfs_trans_unlocked_item */
255
256
257/*
258 * Update the position of the item in the AIL with the new
259 * lsn. If it is not yet in the AIL, add it. Otherwise, move
260 * it to its new position by removing it and re-adding it.
261 *
262 * Wakeup anyone with an lsn less than the item's lsn. If the item
263 * we move in the AIL is the minimum one, update the tail lsn in the
264 * log manager.
265 *
266 * Increment the AIL's generation count to indicate that the tree
267 * has changed.
268 *
269 * This function must be called with the AIL lock held. The lock
Donald Douwsma287f3da2007-10-11 17:36:05 +1000270 * is dropped before returning.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 */
272void
273xfs_trans_update_ail(
274 xfs_mount_t *mp,
275 xfs_log_item_t *lip,
Donald Douwsma287f3da2007-10-11 17:36:05 +1000276 xfs_lsn_t lsn) __releases(mp->m_ail_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277{
278 xfs_ail_entry_t *ailp;
279 xfs_log_item_t *dlip=NULL;
280 xfs_log_item_t *mlip; /* ptr to minimum lip */
281
282 ailp = &(mp->m_ail);
283 mlip = xfs_ail_min(ailp);
284
285 if (lip->li_flags & XFS_LI_IN_AIL) {
286 dlip = xfs_ail_delete(ailp, lip);
287 ASSERT(dlip == lip);
288 } else {
289 lip->li_flags |= XFS_LI_IN_AIL;
290 }
291
292 lip->li_lsn = lsn;
293
294 xfs_ail_insert(ailp, lip);
295 mp->m_ail_gen++;
296
297 if (mlip == dlip) {
298 mlip = xfs_ail_min(&(mp->m_ail));
Donald Douwsma287f3da2007-10-11 17:36:05 +1000299 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 xfs_log_move_tail(mp, mlip->li_lsn);
301 } else {
Donald Douwsma287f3da2007-10-11 17:36:05 +1000302 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303 }
304
305
306} /* xfs_trans_update_ail */
307
308/*
309 * Delete the given item from the AIL. It must already be in
310 * the AIL.
311 *
312 * Wakeup anyone with an lsn less than item's lsn. If the item
313 * we delete in the AIL is the minimum one, update the tail lsn in the
314 * log manager.
315 *
316 * Clear the IN_AIL flag from the item, reset its lsn to 0, and
317 * bump the AIL's generation count to indicate that the tree
318 * has changed.
319 *
320 * This function must be called with the AIL lock held. The lock
Donald Douwsma287f3da2007-10-11 17:36:05 +1000321 * is dropped before returning.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 */
323void
324xfs_trans_delete_ail(
325 xfs_mount_t *mp,
Donald Douwsma287f3da2007-10-11 17:36:05 +1000326 xfs_log_item_t *lip) __releases(mp->m_ail_lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327{
328 xfs_ail_entry_t *ailp;
329 xfs_log_item_t *dlip;
330 xfs_log_item_t *mlip;
331
332 if (lip->li_flags & XFS_LI_IN_AIL) {
333 ailp = &(mp->m_ail);
334 mlip = xfs_ail_min(ailp);
335 dlip = xfs_ail_delete(ailp, lip);
336 ASSERT(dlip == lip);
337
338
339 lip->li_flags &= ~XFS_LI_IN_AIL;
340 lip->li_lsn = 0;
341 mp->m_ail_gen++;
342
343 if (mlip == dlip) {
344 mlip = xfs_ail_min(&(mp->m_ail));
Donald Douwsma287f3da2007-10-11 17:36:05 +1000345 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 xfs_log_move_tail(mp, (mlip ? mlip->li_lsn : 0));
347 } else {
Donald Douwsma287f3da2007-10-11 17:36:05 +1000348 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 }
350 }
351 else {
352 /*
353 * If the file system is not being shutdown, we are in
354 * serious trouble if we get to this stage.
355 */
356 if (XFS_FORCED_SHUTDOWN(mp))
Donald Douwsma287f3da2007-10-11 17:36:05 +1000357 spin_unlock(&mp->m_ail_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 else {
359 xfs_cmn_err(XFS_PTAG_AILDELETE, CE_ALERT, mp,
Nathan Scott7d04a332006-06-09 14:58:38 +1000360 "%s: attempting to delete a log item that is not in the AIL",
361 __FUNCTION__);
Donald Douwsma287f3da2007-10-11 17:36:05 +1000362 spin_unlock(&mp->m_ail_lock);
Nathan Scott7d04a332006-06-09 14:58:38 +1000363 xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 }
365 }
366}
367
368
369
370/*
371 * Return the item in the AIL with the smallest lsn.
372 * Return the current tree generation number for use
373 * in calls to xfs_trans_next_ail().
374 */
375xfs_log_item_t *
376xfs_trans_first_ail(
377 xfs_mount_t *mp,
378 int *gen)
379{
380 xfs_log_item_t *lip;
381
382 lip = xfs_ail_min(&(mp->m_ail));
383 *gen = (int)mp->m_ail_gen;
384
385 return (lip);
386}
387
388/*
389 * If the generation count of the tree has not changed since the
390 * caller last took something from the AIL, then return the elmt
391 * in the tree which follows the one given. If the count has changed,
392 * then return the minimum elmt of the AIL and bump the restarts counter
393 * if one is given.
394 */
395xfs_log_item_t *
396xfs_trans_next_ail(
397 xfs_mount_t *mp,
398 xfs_log_item_t *lip,
399 int *gen,
400 int *restarts)
401{
402 xfs_log_item_t *nlip;
403
404 ASSERT(mp && lip && gen);
405 if (mp->m_ail_gen == *gen) {
406 nlip = xfs_ail_next(&(mp->m_ail), lip);
407 } else {
408 nlip = xfs_ail_min(&(mp->m_ail));
409 *gen = (int)mp->m_ail_gen;
410 if (restarts != NULL) {
411 XFS_STATS_INC(xs_push_ail_restarts);
412 (*restarts)++;
413 }
414 }
415
416 return (nlip);
417}
418
419
420/*
421 * The active item list (AIL) is a doubly linked list of log
422 * items sorted by ascending lsn. The base of the list is
423 * a forw/back pointer pair embedded in the xfs mount structure.
424 * The base is initialized with both pointers pointing to the
425 * base. This case always needs to be distinguished, because
426 * the base has no lsn to look at. We almost always insert
427 * at the end of the list, so on inserts we search from the
428 * end of the list to find where the new item belongs.
429 */
430
431/*
432 * Initialize the doubly linked list to point only to itself.
433 */
434void
435xfs_trans_ail_init(
436 xfs_mount_t *mp)
437{
438 mp->m_ail.ail_forw = (xfs_log_item_t*)&(mp->m_ail);
439 mp->m_ail.ail_back = (xfs_log_item_t*)&(mp->m_ail);
440}
441
442/*
443 * Insert the given log item into the AIL.
444 * We almost always insert at the end of the list, so on inserts
445 * we search from the end of the list to find where the
446 * new item belongs.
447 */
448STATIC void
449xfs_ail_insert(
450 xfs_ail_entry_t *base,
451 xfs_log_item_t *lip)
452/* ARGSUSED */
453{
454 xfs_log_item_t *next_lip;
455
456 /*
457 * If the list is empty, just insert the item.
458 */
459 if (base->ail_back == (xfs_log_item_t*)base) {
460 base->ail_forw = lip;
461 base->ail_back = lip;
462 lip->li_ail.ail_forw = (xfs_log_item_t*)base;
463 lip->li_ail.ail_back = (xfs_log_item_t*)base;
464 return;
465 }
466
467 next_lip = base->ail_back;
468 while ((next_lip != (xfs_log_item_t*)base) &&
469 (XFS_LSN_CMP(next_lip->li_lsn, lip->li_lsn) > 0)) {
470 next_lip = next_lip->li_ail.ail_back;
471 }
472 ASSERT((next_lip == (xfs_log_item_t*)base) ||
473 (XFS_LSN_CMP(next_lip->li_lsn, lip->li_lsn) <= 0));
474 lip->li_ail.ail_forw = next_lip->li_ail.ail_forw;
475 lip->li_ail.ail_back = next_lip;
476 next_lip->li_ail.ail_forw = lip;
477 lip->li_ail.ail_forw->li_ail.ail_back = lip;
478
479 xfs_ail_check(base);
480 return;
481}
482
483/*
484 * Delete the given item from the AIL. Return a pointer to the item.
485 */
486/*ARGSUSED*/
487STATIC xfs_log_item_t *
488xfs_ail_delete(
489 xfs_ail_entry_t *base,
490 xfs_log_item_t *lip)
491/* ARGSUSED */
492{
493 lip->li_ail.ail_forw->li_ail.ail_back = lip->li_ail.ail_back;
494 lip->li_ail.ail_back->li_ail.ail_forw = lip->li_ail.ail_forw;
495 lip->li_ail.ail_forw = NULL;
496 lip->li_ail.ail_back = NULL;
497
498 xfs_ail_check(base);
499 return lip;
500}
501
502/*
503 * Return a pointer to the first item in the AIL.
504 * If the AIL is empty, then return NULL.
505 */
506STATIC xfs_log_item_t *
507xfs_ail_min(
508 xfs_ail_entry_t *base)
509/* ARGSUSED */
510{
511 register xfs_log_item_t *forw = base->ail_forw;
512 if (forw == (xfs_log_item_t*)base) {
513 return NULL;
514 }
515 return forw;
516}
517
518/*
519 * Return a pointer to the item which follows
520 * the given item in the AIL. If the given item
521 * is the last item in the list, then return NULL.
522 */
523STATIC xfs_log_item_t *
524xfs_ail_next(
525 xfs_ail_entry_t *base,
526 xfs_log_item_t *lip)
527/* ARGSUSED */
528{
529 if (lip->li_ail.ail_forw == (xfs_log_item_t*)base) {
530 return NULL;
531 }
532 return lip->li_ail.ail_forw;
533
534}
535
536#ifdef DEBUG
537/*
538 * Check that the list is sorted as it should be.
539 */
540STATIC void
541xfs_ail_check(
542 xfs_ail_entry_t *base)
543{
544 xfs_log_item_t *lip;
545 xfs_log_item_t *prev_lip;
546
547 lip = base->ail_forw;
548 if (lip == (xfs_log_item_t*)base) {
549 /*
550 * Make sure the pointers are correct when the list
551 * is empty.
552 */
553 ASSERT(base->ail_back == (xfs_log_item_t*)base);
554 return;
555 }
556
557 /*
558 * Walk the list checking forward and backward pointers,
559 * lsn ordering, and that every entry has the XFS_LI_IN_AIL
560 * flag set.
561 */
562 prev_lip = (xfs_log_item_t*)base;
563 while (lip != (xfs_log_item_t*)base) {
564 if (prev_lip != (xfs_log_item_t*)base) {
565 ASSERT(prev_lip->li_ail.ail_forw == lip);
566 ASSERT(XFS_LSN_CMP(prev_lip->li_lsn, lip->li_lsn) <= 0);
567 }
568 ASSERT(lip->li_ail.ail_back == prev_lip);
569 ASSERT((lip->li_flags & XFS_LI_IN_AIL) != 0);
570 prev_lip = lip;
571 lip = lip->li_ail.ail_forw;
572 }
573 ASSERT(lip == (xfs_log_item_t*)base);
574 ASSERT(base->ail_back == prev_lip);
575}
576#endif /* DEBUG */