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usb: renesas_usbhs: disable TX IRQ before starting TX DMAC transfer
[linux/fpc-iii.git] / fs / xfs / xfs_extent_busy.c
blobfd22f69049d49861ff1f853ec11a2d23e3eef03f
1 /*
2 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
3 * Copyright (c) 2010 David Chinner.
4 * Copyright (c) 2011 Christoph Hellwig.
5 * All Rights Reserved.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it would be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20 #include "xfs.h"
21 #include "xfs_fs.h"
22 #include "xfs_format.h"
23 #include "xfs_log_format.h"
24 #include "xfs_shared.h"
25 #include "xfs_trans_resv.h"
26 #include "xfs_sb.h"
27 #include "xfs_ag.h"
28 #include "xfs_mount.h"
29 #include "xfs_alloc.h"
30 #include "xfs_extent_busy.h"
31 #include "xfs_trace.h"
32 #include "xfs_trans.h"
33 #include "xfs_log.h"
34
35 void
36 xfs_extent_busy_insert(
37 struct xfs_trans *tp,
38 xfs_agnumber_t agno,
39 xfs_agblock_t bno,
40 xfs_extlen_t len,
41 unsigned int flags)
42 {
43 struct xfs_extent_busy *new;
44 struct xfs_extent_busy *busyp;
45 struct xfs_perag *pag;
46 struct rb_node **rbp;
47 struct rb_node *parent = NULL;
48
49 new = kmem_zalloc(sizeof(struct xfs_extent_busy), KM_MAYFAIL);
50 if (!new) {
51 /*
52 * No Memory! Since it is now not possible to track the free
53 * block, make this a synchronous transaction to insure that
54 * the block is not reused before this transaction commits.
55 */
56 trace_xfs_extent_busy_enomem(tp->t_mountp, agno, bno, len);
57 xfs_trans_set_sync(tp);
58 return;
59 }
60
61 new->agno = agno;
62 new->bno = bno;
63 new->length = len;
64 INIT_LIST_HEAD(&new->list);
65 new->flags = flags;
66
67 /* trace before insert to be able to see failed inserts */
68 trace_xfs_extent_busy(tp->t_mountp, agno, bno, len);
69
70 pag = xfs_perag_get(tp->t_mountp, new->agno);
71 spin_lock(&pag->pagb_lock);
72 rbp = &pag->pagb_tree.rb_node;
73 while (*rbp) {
74 parent = *rbp;
75 busyp = rb_entry(parent, struct xfs_extent_busy, rb_node);
76
77 if (new->bno < busyp->bno) {
78 rbp = &(*rbp)->rb_left;
79 ASSERT(new->bno + new->length <= busyp->bno);
80 } else if (new->bno > busyp->bno) {
81 rbp = &(*rbp)->rb_right;
82 ASSERT(bno >= busyp->bno + busyp->length);
83 } else {
84 ASSERT(0);
85 }
86 }
87
88 rb_link_node(&new->rb_node, parent, rbp);
89 rb_insert_color(&new->rb_node, &pag->pagb_tree);
90
91 list_add(&new->list, &tp->t_busy);
92 spin_unlock(&pag->pagb_lock);
93 xfs_perag_put(pag);
94 }
95
96 /*
97 * Search for a busy extent within the range of the extent we are about to
98 * allocate. You need to be holding the busy extent tree lock when calling
99 * xfs_extent_busy_search(). This function returns 0 for no overlapping busy
100 * extent, -1 for an overlapping but not exact busy extent, and 1 for an exact
101 * match. This is done so that a non-zero return indicates an overlap that
102 * will require a synchronous transaction, but it can still be
103 * used to distinguish between a partial or exact match.
104 */
105 int
106 xfs_extent_busy_search(
107 struct xfs_mount *mp,
108 xfs_agnumber_t agno,
109 xfs_agblock_t bno,
110 xfs_extlen_t len)
111 {
112 struct xfs_perag *pag;
113 struct rb_node *rbp;
114 struct xfs_extent_busy *busyp;
115 int match = 0;
116
117 pag = xfs_perag_get(mp, agno);
118 spin_lock(&pag->pagb_lock);
119
120 rbp = pag->pagb_tree.rb_node;
121
122 /* find closest start bno overlap */
123 while (rbp) {
124 busyp = rb_entry(rbp, struct xfs_extent_busy, rb_node);
125 if (bno < busyp->bno) {
126 /* may overlap, but exact start block is lower */
127 if (bno + len > busyp->bno)
128 match = -1;
129 rbp = rbp->rb_left;
130 } else if (bno > busyp->bno) {
131 /* may overlap, but exact start block is higher */
132 if (bno < busyp->bno + busyp->length)
133 match = -1;
134 rbp = rbp->rb_right;
135 } else {
136 /* bno matches busyp, length determines exact match */
137 match = (busyp->length == len) ? 1 : -1;
138 break;
139 }
140 }
141 spin_unlock(&pag->pagb_lock);
142 xfs_perag_put(pag);
143 return match;
144 }
145
146 /*
147 * The found free extent [fbno, fend] overlaps part or all of the given busy
148 * extent. If the overlap covers the beginning, the end, or all of the busy
149 * extent, the overlapping portion can be made unbusy and used for the
150 * allocation. We can't split a busy extent because we can't modify a
151 * transaction/CIL context busy list, but we can update an entry's block
152 * number or length.
153 *
154 * Returns true if the extent can safely be reused, or false if the search
155 * needs to be restarted.
156 */
157 STATIC bool
158 xfs_extent_busy_update_extent(
159 struct xfs_mount *mp,
160 struct xfs_perag *pag,
161 struct xfs_extent_busy *busyp,
162 xfs_agblock_t fbno,
163 xfs_extlen_t flen,
164 bool userdata) __releases(&pag->pagb_lock)
165 __acquires(&pag->pagb_lock)
166 {
167 xfs_agblock_t fend = fbno + flen;
168 xfs_agblock_t bbno = busyp->bno;
169 xfs_agblock_t bend = bbno + busyp->length;
170
171 /*
172 * This extent is currently being discarded. Give the thread
173 * performing the discard a chance to mark the extent unbusy
174 * and retry.
175 */
176 if (busyp->flags & XFS_EXTENT_BUSY_DISCARDED) {
177 spin_unlock(&pag->pagb_lock);
178 delay(1);
179 spin_lock(&pag->pagb_lock);
180 return false;
181 }
182
183 /*
184 * If there is a busy extent overlapping a user allocation, we have
185 * no choice but to force the log and retry the search.
186 *
187 * Fortunately this does not happen during normal operation, but
188 * only if the filesystem is very low on space and has to dip into
189 * the AGFL for normal allocations.
190 */
191 if (userdata)
192 goto out_force_log;
193
194 if (bbno < fbno && bend > fend) {
195 /*
196 * Case 1:
197 * bbno bend
198 * +BBBBBBBBBBBBBBBBB+
199 * +---------+
200 * fbno fend
201 */
202
203 /*
204 * We would have to split the busy extent to be able to track
205 * it correct, which we cannot do because we would have to
206 * modify the list of busy extents attached to the transaction
207 * or CIL context, which is immutable.
208 *
209 * Force out the log to clear the busy extent and retry the
210 * search.
211 */
212 goto out_force_log;
213 } else if (bbno >= fbno && bend <= fend) {
214 /*
215 * Case 2:
216 * bbno bend
217 * +BBBBBBBBBBBBBBBBB+
218 * +-----------------+
219 * fbno fend
220 *
221 * Case 3:
222 * bbno bend
223 * +BBBBBBBBBBBBBBBBB+
224 * +--------------------------+
225 * fbno fend
226 *
227 * Case 4:
228 * bbno bend
229 * +BBBBBBBBBBBBBBBBB+
230 * +--------------------------+
231 * fbno fend
232 *
233 * Case 5:
234 * bbno bend
235 * +BBBBBBBBBBBBBBBBB+
236 * +-----------------------------------+
237 * fbno fend
238 *
239 */
240
241 /*
242 * The busy extent is fully covered by the extent we are
243 * allocating, and can simply be removed from the rbtree.
244 * However we cannot remove it from the immutable list
245 * tracking busy extents in the transaction or CIL context,
246 * so set the length to zero to mark it invalid.
247 *
248 * We also need to restart the busy extent search from the
249 * tree root, because erasing the node can rearrange the
250 * tree topology.
251 */
252 rb_erase(&busyp->rb_node, &pag->pagb_tree);
253 busyp->length = 0;
254 return false;
255 } else if (fend < bend) {
256 /*
257 * Case 6:
258 * bbno bend
259 * +BBBBBBBBBBBBBBBBB+
260 * +---------+
261 * fbno fend
262 *
263 * Case 7:
264 * bbno bend
265 * +BBBBBBBBBBBBBBBBB+
266 * +------------------+
267 * fbno fend
268 *
269 */
270 busyp->bno = fend;
271 } else if (bbno < fbno) {
272 /*
273 * Case 8:
274 * bbno bend
275 * +BBBBBBBBBBBBBBBBB+
276 * +-------------+
277 * fbno fend
278 *
279 * Case 9:
280 * bbno bend
281 * +BBBBBBBBBBBBBBBBB+
282 * +----------------------+
283 * fbno fend
284 */
285 busyp->length = fbno - busyp->bno;
286 } else {
287 ASSERT(0);
288 }
289
290 trace_xfs_extent_busy_reuse(mp, pag->pag_agno, fbno, flen);
291 return true;
292
293 out_force_log:
294 spin_unlock(&pag->pagb_lock);
295 xfs_log_force(mp, XFS_LOG_SYNC);
296 trace_xfs_extent_busy_force(mp, pag->pag_agno, fbno, flen);
297 spin_lock(&pag->pagb_lock);
298 return false;
299 }
300
301
302 /*
303 * For a given extent [fbno, flen], make sure we can reuse it safely.
304 */
305 void
306 xfs_extent_busy_reuse(
307 struct xfs_mount *mp,
308 xfs_agnumber_t agno,
309 xfs_agblock_t fbno,
310 xfs_extlen_t flen,
311 bool userdata)
312 {
313 struct xfs_perag *pag;
314 struct rb_node *rbp;
315
316 ASSERT(flen > 0);
317
318 pag = xfs_perag_get(mp, agno);
319 spin_lock(&pag->pagb_lock);
320 restart:
321 rbp = pag->pagb_tree.rb_node;
322 while (rbp) {
323 struct xfs_extent_busy *busyp =
324 rb_entry(rbp, struct xfs_extent_busy, rb_node);
325 xfs_agblock_t bbno = busyp->bno;
326 xfs_agblock_t bend = bbno + busyp->length;
327
328 if (fbno + flen <= bbno) {
329 rbp = rbp->rb_left;
330 continue;
331 } else if (fbno >= bend) {
332 rbp = rbp->rb_right;
333 continue;
334 }
335
336 if (!xfs_extent_busy_update_extent(mp, pag, busyp, fbno, flen,
337 userdata))
338 goto restart;
339 }
340 spin_unlock(&pag->pagb_lock);
341 xfs_perag_put(pag);
342 }
343
344 /*
345 * For a given extent [fbno, flen], search the busy extent list to find a
346 * subset of the extent that is not busy. If *rlen is smaller than
347 * args->minlen no suitable extent could be found, and the higher level
348 * code needs to force out the log and retry the allocation.
349 */
350 void
351 xfs_extent_busy_trim(
352 struct xfs_alloc_arg *args,
353 xfs_agblock_t bno,
354 xfs_extlen_t len,
355 xfs_agblock_t *rbno,
356 xfs_extlen_t *rlen)
357 {
358 xfs_agblock_t fbno;
359 xfs_extlen_t flen;
360 struct rb_node *rbp;
361
362 ASSERT(len > 0);
363
364 spin_lock(&args->pag->pagb_lock);
365 restart:
366 fbno = bno;
367 flen = len;
368 rbp = args->pag->pagb_tree.rb_node;
369 while (rbp && flen >= args->minlen) {
370 struct xfs_extent_busy *busyp =
371 rb_entry(rbp, struct xfs_extent_busy, rb_node);
372 xfs_agblock_t fend = fbno + flen;
373 xfs_agblock_t bbno = busyp->bno;
374 xfs_agblock_t bend = bbno + busyp->length;
375
376 if (fend <= bbno) {
377 rbp = rbp->rb_left;
378 continue;
379 } else if (fbno >= bend) {
380 rbp = rbp->rb_right;
381 continue;
382 }
383
384 /*
385 * If this is a metadata allocation, try to reuse the busy
386 * extent instead of trimming the allocation.
387 */
388 if (!args->userdata &&
389 !(busyp->flags & XFS_EXTENT_BUSY_DISCARDED)) {
390 if (!xfs_extent_busy_update_extent(args->mp, args->pag,
391 busyp, fbno, flen,
392 false))
393 goto restart;
394 continue;
395 }
396
397 if (bbno <= fbno) {
398 /* start overlap */
399
400 /*
401 * Case 1:
402 * bbno bend
403 * +BBBBBBBBBBBBBBBBB+
404 * +---------+
405 * fbno fend
406 *
407 * Case 2:
408 * bbno bend
409 * +BBBBBBBBBBBBBBBBB+
410 * +-------------+
411 * fbno fend
412 *
413 * Case 3:
414 * bbno bend
415 * +BBBBBBBBBBBBBBBBB+
416 * +-------------+
417 * fbno fend
418 *
419 * Case 4:
420 * bbno bend
421 * +BBBBBBBBBBBBBBBBB+
422 * +-----------------+
423 * fbno fend
424 *
425 * No unbusy region in extent, return failure.
426 */
427 if (fend <= bend)
428 goto fail;
429
430 /*
431 * Case 5:
432 * bbno bend
433 * +BBBBBBBBBBBBBBBBB+
434 * +----------------------+
435 * fbno fend
436 *
437 * Case 6:
438 * bbno bend
439 * +BBBBBBBBBBBBBBBBB+
440 * +--------------------------+
441 * fbno fend
442 *
443 * Needs to be trimmed to:
444 * +-------+
445 * fbno fend
446 */
447 fbno = bend;
448 } else if (bend >= fend) {
449 /* end overlap */
450
451 /*
452 * Case 7:
453 * bbno bend
454 * +BBBBBBBBBBBBBBBBB+
455 * +------------------+
456 * fbno fend
457 *
458 * Case 8:
459 * bbno bend
460 * +BBBBBBBBBBBBBBBBB+
461 * +--------------------------+
462 * fbno fend
463 *
464 * Needs to be trimmed to:
465 * +-------+
466 * fbno fend
467 */
468 fend = bbno;
469 } else {
470 /* middle overlap */
471
472 /*
473 * Case 9:
474 * bbno bend
475 * +BBBBBBBBBBBBBBBBB+
476 * +-----------------------------------+
477 * fbno fend
478 *
479 * Can be trimmed to:
480 * +-------+ OR +-------+
481 * fbno fend fbno fend
482 *
483 * Backward allocation leads to significant
484 * fragmentation of directories, which degrades
485 * directory performance, therefore we always want to
486 * choose the option that produces forward allocation
487 * patterns.
488 * Preferring the lower bno extent will make the next
489 * request use "fend" as the start of the next
490 * allocation; if the segment is no longer busy at
491 * that point, we'll get a contiguous allocation, but
492 * even if it is still busy, we will get a forward
493 * allocation.
494 * We try to avoid choosing the segment at "bend",
495 * because that can lead to the next allocation
496 * taking the segment at "fbno", which would be a
497 * backward allocation. We only use the segment at
498 * "fbno" if it is much larger than the current
499 * requested size, because in that case there's a
500 * good chance subsequent allocations will be
501 * contiguous.
502 */
503 if (bbno - fbno >= args->maxlen) {
504 /* left candidate fits perfect */
505 fend = bbno;
506 } else if (fend - bend >= args->maxlen * 4) {
507 /* right candidate has enough free space */
508 fbno = bend;
509 } else if (bbno - fbno >= args->minlen) {
510 /* left candidate fits minimum requirement */
511 fend = bbno;
512 } else {
513 goto fail;
514 }
515 }
516
517 flen = fend - fbno;
518 }
519 spin_unlock(&args->pag->pagb_lock);
520
521 if (fbno != bno || flen != len) {
522 trace_xfs_extent_busy_trim(args->mp, args->agno, bno, len,
523 fbno, flen);
524 }
525 *rbno = fbno;
526 *rlen = flen;
527 return;
528 fail:
529 /*
530 * Return a zero extent length as failure indications. All callers
531 * re-check if the trimmed extent satisfies the minlen requirement.
532 */
533 spin_unlock(&args->pag->pagb_lock);
534 trace_xfs_extent_busy_trim(args->mp, args->agno, bno, len, fbno, 0);
535 *rbno = fbno;
536 *rlen = 0;
537 }
538
539 STATIC void
540 xfs_extent_busy_clear_one(
541 struct xfs_mount *mp,
542 struct xfs_perag *pag,
543 struct xfs_extent_busy *busyp)
544 {
545 if (busyp->length) {
546 trace_xfs_extent_busy_clear(mp, busyp->agno, busyp->bno,
547 busyp->length);
548 rb_erase(&busyp->rb_node, &pag->pagb_tree);
549 }
550
551 list_del_init(&busyp->list);
552 kmem_free(busyp);
553 }
554
555 /*
556 * Remove all extents on the passed in list from the busy extents tree.
557 * If do_discard is set skip extents that need to be discarded, and mark
558 * these as undergoing a discard operation instead.
559 */
560 void
561 xfs_extent_busy_clear(
562 struct xfs_mount *mp,
563 struct list_head *list,
564 bool do_discard)
565 {
566 struct xfs_extent_busy *busyp, *n;
567 struct xfs_perag *pag = NULL;
568 xfs_agnumber_t agno = NULLAGNUMBER;
569
570 list_for_each_entry_safe(busyp, n, list, list) {
571 if (busyp->agno != agno) {
572 if (pag) {
573 spin_unlock(&pag->pagb_lock);
574 xfs_perag_put(pag);
575 }
576 pag = xfs_perag_get(mp, busyp->agno);
577 spin_lock(&pag->pagb_lock);
578 agno = busyp->agno;
579 }
580
581 if (do_discard && busyp->length &&
582 !(busyp->flags & XFS_EXTENT_BUSY_SKIP_DISCARD))
583 busyp->flags = XFS_EXTENT_BUSY_DISCARDED;
584 else
585 xfs_extent_busy_clear_one(mp, pag, busyp);
586 }
587
588 if (pag) {
589 spin_unlock(&pag->pagb_lock);
590 xfs_perag_put(pag);
591 }
592 }
593
594 /*
595 * Callback for list_sort to sort busy extents by the AG they reside in.
596 */
597 int
598 xfs_extent_busy_ag_cmp(
599 void *priv,
600 struct list_head *a,
601 struct list_head *b)
602 {
603 return container_of(a, struct xfs_extent_busy, list)->agno -
604 container_of(b, struct xfs_extent_busy, list)->agno;
605 }
Linux with added FPC-III support