1 /*
2 * Copyright (c) 2007-2008 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34 /*
35 * IO Primitives and buffer cache management
36 *
37 * All major data-tracking structures in HAMMER contain a struct hammer_io
38 * which is used to manage their backing store. We use filesystem buffers
39 * for backing store and we leave them passively associated with their
40 * HAMMER structures.
41 *
42 * If the kernel tries to destroy a passively associated buf which we cannot
43 * yet let go we set B_LOCKED in the buffer and then actively released it
44 * later when we can.
45 *
46 * The io_token is required for anything which might race bioops and bio_done
47 * callbacks, with one exception: A successful hammer_try_interlock_norefs().
48 * the fs_token will be held in all other cases.
49 */
50
51 #include <sys/buf2.h>
52
53 #include "hammer.h"
54
55 static void hammer_io_modify(hammer_io_t io, int count);
56 static void hammer_io_deallocate(struct buf *bp);
57 static void hammer_indirect_callback(struct bio *bio);
58 static void hammer_io_direct_write_complete(struct bio *nbio);
59 static int hammer_io_direct_uncache_callback(hammer_inode_t ip, void *data);
60 static void hammer_io_set_modlist(hammer_io_t io);
61 static __inline void hammer_io_flush_mark(hammer_volume_t volume);
62 static struct bio_ops hammer_bioops;
63
64 static int
hammer_mod_rb_compare(hammer_io_t io1,hammer_io_t io2)65 hammer_mod_rb_compare(hammer_io_t io1, hammer_io_t io2)
66 {
67 hammer_off_t io1_offset;
68 hammer_off_t io2_offset;
69
70 /*
71 * Encoded offsets are neither valid block device offsets
72 * nor valid zone-X offsets.
73 */
74 io1_offset = HAMMER_ENCODE(0, io1->volume->vol_no, io1->offset);
75 io2_offset = HAMMER_ENCODE(0, io2->volume->vol_no, io2->offset);
76
77 if (io1_offset < io2_offset)
78 return(-1);
79 if (io1_offset > io2_offset)
80 return(1);
81 return(0);
82 }
83
84 RB_GENERATE(hammer_mod_rb_tree, hammer_io, rb_node, hammer_mod_rb_compare);
85
86 /*
87 * Initialize a new, already-zero'd hammer_io structure, or reinitialize
88 * an existing hammer_io structure which may have switched to another type.
89 */
90 void
hammer_io_init(hammer_io_t io,hammer_volume_t volume,hammer_io_type_t type)91 hammer_io_init(hammer_io_t io, hammer_volume_t volume, hammer_io_type_t type)
92 {
93 io->volume = volume;
94 io->hmp = volume->io.hmp;
95 io->type = type;
96 }
97
98 hammer_io_type_t
hammer_zone_to_iotype(int zone)99 hammer_zone_to_iotype(int zone)
100 {
101 hammer_io_type_t iotype;
102
103 switch(zone) {
104 case HAMMER_ZONE_RAW_VOLUME_INDEX:
105 iotype = HAMMER_IOTYPE_VOLUME;
106 break;
107 case HAMMER_ZONE_RAW_BUFFER_INDEX:
108 case HAMMER_ZONE_FREEMAP_INDEX:
109 case HAMMER_ZONE_BTREE_INDEX:
110 case HAMMER_ZONE_META_INDEX:
111 iotype = HAMMER_IOTYPE_META_BUFFER;
112 break;
113 case HAMMER_ZONE_UNDO_INDEX:
114 iotype = HAMMER_IOTYPE_UNDO_BUFFER;
115 break;
116 case HAMMER_ZONE_LARGE_DATA_INDEX:
117 case HAMMER_ZONE_SMALL_DATA_INDEX:
118 iotype = HAMMER_IOTYPE_DATA_BUFFER;
119 break;
120 default:
121 iotype = HAMMER_IOTYPE_DUMMY;
122 break;
123 }
124
125 return(iotype);
126 }
127
128 static const char*
hammer_io_to_iostring(hammer_io_t io)129 hammer_io_to_iostring(hammer_io_t io)
130 {
131 const char *iostr = NULL;
132
133 switch(io->type) {
134 case HAMMER_IOTYPE_VOLUME:
135 iostr = "volume";
136 break;
137 case HAMMER_IOTYPE_META_BUFFER:
138 switch(HAMMER_ZONE(HAMMER_ITOB(io)->zoneX_offset)) {
139 case HAMMER_ZONE_RAW_BUFFER:
140 iostr = "meta/raw_buffer";
141 break;
142 case HAMMER_ZONE_FREEMAP:
143 iostr = "meta/freemap";
144 break;
145 case HAMMER_ZONE_BTREE:
146 iostr = "meta/btree";
147 break;
148 case HAMMER_ZONE_META:
149 iostr = "meta/meta";
150 break;
151 }
152 break;
153 case HAMMER_IOTYPE_UNDO_BUFFER:
154 iostr = "undo";
155 break;
156 case HAMMER_IOTYPE_DATA_BUFFER:
157 switch(HAMMER_ZONE(HAMMER_ITOB(io)->zoneX_offset)) {
158 case HAMMER_ZONE_LARGE_DATA:
159 iostr = "data/large_data";
160 break;
161 case HAMMER_ZONE_SMALL_DATA:
162 iostr = "data/small_data";
163 break;
164 }
165 break;
166 case HAMMER_IOTYPE_DUMMY:
167 iostr = "dummy";
168 break;
169 default:
170 hpanic("bad io type");
171 break;
172 }
173
174 return(iostr);
175 }
176
177 /*
178 * Helper routine to disassociate a buffer cache buffer from an I/O
179 * structure. The io must be interlocked and marked appropriately for
180 * reclamation.
181 *
182 * The io must be in a released state with the io->bp owned and
183 * locked by the caller of this function. When not called from an
184 * io_deallocate() this cannot race an io_deallocate() since the
185 * kernel would be unable to get the buffer lock in that case.
186 * (The released state in this case means we own the bp, not the
187 * hammer_io structure).
188 *
189 * The io may have 0 or 1 references depending on who called us. The
190 * caller is responsible for dealing with the refs.
191 *
192 * This call can only be made when no action is required on the buffer.
193 *
194 * This function is guaranteed not to race against anything because we
195 * own both the io lock and the bp lock and are interlocked with no
196 * references.
197 */
198 static void
hammer_io_disassociate(hammer_io_t io)199 hammer_io_disassociate(hammer_io_t io)
200 {
201 struct buf *bp = io->bp;
202
203 KKASSERT(io->released);
204 KKASSERT(io->modified == 0);
205 KKASSERT(hammer_buf_peek_io(bp) == io);
206 buf_dep_init(bp);
207 io->bp = NULL;
208
209 /*
210 * If the buffer was locked someone wanted to get rid of it.
211 */
212 if (bp->b_flags & B_LOCKED) {
213 atomic_add_int(&hammer_count_io_locked, -1);
214 bp->b_flags &= ~B_LOCKED;
215 }
216 if (io->reclaim) {
217 bp->b_flags |= B_NOCACHE|B_RELBUF;
218 io->reclaim = 0;
219 }
220
221 switch(io->type) {
222 case HAMMER_IOTYPE_VOLUME:
223 HAMMER_ITOV(io)->ondisk = NULL;
224 break;
225 case HAMMER_IOTYPE_DATA_BUFFER:
226 case HAMMER_IOTYPE_META_BUFFER:
227 case HAMMER_IOTYPE_UNDO_BUFFER:
228 HAMMER_ITOB(io)->ondisk = NULL;
229 break;
230 case HAMMER_IOTYPE_DUMMY:
231 hpanic("bad io type");
232 break;
233 }
234 }
235
236 /*
237 * Wait for any physical IO to complete
238 *
239 * XXX we aren't interlocked against a spinlock or anything so there
240 * is a small window in the interlock / io->running == 0 test.
241 */
242 void
hammer_io_wait(hammer_io_t io)243 hammer_io_wait(hammer_io_t io)
244 {
245 if (io->running) {
246 hammer_mount_t hmp = io->hmp;
247
248 lwkt_gettoken(&hmp->io_token);
249 while (io->running) {
250 io->waiting = 1;
251 tsleep_interlock(io, 0);
252 if (io->running)
253 tsleep(io, PINTERLOCKED, "hmrflw", hz);
254 }
255 lwkt_reltoken(&hmp->io_token);
256 }
257 }
258
259 /*
260 * Wait for all currently queued HAMMER-initiated I/Os to complete.
261 *
262 * This is not supposed to count direct I/O's but some can leak
263 * through (for non-full-sized direct I/Os).
264 */
265 void
hammer_io_wait_all(hammer_mount_t hmp,const char * ident,int doflush)266 hammer_io_wait_all(hammer_mount_t hmp, const char *ident, int doflush)
267 {
268 struct hammer_io iodummy;
269 hammer_io_t io;
270
271 /*
272 * Degenerate case, no I/O is running
273 */
274 lwkt_gettoken(&hmp->io_token);
275 if (TAILQ_EMPTY(&hmp->iorun_list)) {
276 lwkt_reltoken(&hmp->io_token);
277 if (doflush)
278 hammer_io_flush_sync(hmp);
279 return;
280 }
281 bzero(&iodummy, sizeof(iodummy));
282 iodummy.type = HAMMER_IOTYPE_DUMMY;
283
284 /*
285 * Add placemarker and then wait until it becomes the head of
286 * the list.
287 */
288 TAILQ_INSERT_TAIL(&hmp->iorun_list, &iodummy, iorun_entry);
289 while (TAILQ_FIRST(&hmp->iorun_list) != &iodummy) {
290 tsleep(&iodummy, 0, ident, 0);
291 }
292
293 /*
294 * Chain in case several placemarkers are present.
295 */
296 TAILQ_REMOVE(&hmp->iorun_list, &iodummy, iorun_entry);
297 io = TAILQ_FIRST(&hmp->iorun_list);
298 if (io && io->type == HAMMER_IOTYPE_DUMMY)
299 wakeup(io);
300 lwkt_reltoken(&hmp->io_token);
301
302 if (doflush)
303 hammer_io_flush_sync(hmp);
304 }
305
306 /*
307 * Clear a flagged error condition on a I/O buffer. The caller must hold
308 * its own ref on the buffer.
309 */
310 void
hammer_io_clear_error(hammer_io_t io)311 hammer_io_clear_error(hammer_io_t io)
312 {
313 hammer_mount_t hmp = io->hmp;
314
315 lwkt_gettoken(&hmp->io_token);
316 if (io->ioerror) {
317 io->ioerror = 0;
318 hammer_rel(&io->lock);
319 KKASSERT(hammer_isactive(&io->lock));
320 }
321 lwkt_reltoken(&hmp->io_token);
322 }
323
324 void
hammer_io_clear_error_noassert(hammer_io_t io)325 hammer_io_clear_error_noassert(hammer_io_t io)
326 {
327 hammer_mount_t hmp = io->hmp;
328
329 lwkt_gettoken(&hmp->io_token);
330 if (io->ioerror) {
331 io->ioerror = 0;
332 hammer_rel(&io->lock);
333 }
334 lwkt_reltoken(&hmp->io_token);
335 }
336
337 /*
338 * This is an advisory function only which tells the buffer cache
339 * the bp is not a meta-data buffer, even though it is backed by
340 * a block device.
341 *
342 * This is used by HAMMER's reblocking code to avoid trying to
343 * swapcache the filesystem's data when it is read or written
344 * by the reblocking code.
345 *
346 * The caller has a ref on the buffer preventing the bp from
347 * being disassociated from it.
348 */
349 void
hammer_io_notmeta(hammer_buffer_t buffer)350 hammer_io_notmeta(hammer_buffer_t buffer)
351 {
352 if ((buffer->io.bp->b_flags & B_NOTMETA) == 0) {
353 hammer_mount_t hmp = buffer->io.hmp;
354
355 lwkt_gettoken(&hmp->io_token);
356 buffer->io.bp->b_flags |= B_NOTMETA;
357 lwkt_reltoken(&hmp->io_token);
358 }
359 }
360
361 /*
362 * Load bp for a HAMMER structure. The io must be exclusively locked by
363 * the caller.
364 *
365 * This routine is mostly used on meta-data and small-data blocks. Generally
366 * speaking HAMMER assumes some locality of reference and will cluster.
367 *
368 * Note that the caller (hammer_ondisk.c) may place further restrictions
369 * on clusterability via the limit (in bytes). Typically large-data
370 * zones cannot be clustered due to their mixed buffer sizes. This is
371 * not an issue since such clustering occurs in hammer_vnops at the
372 * regular file layer, whereas this is the buffered block device layer.
373 *
374 * No I/O callbacks can occur while we hold the buffer locked.
375 */
376 int
hammer_io_read(struct vnode * devvp,hammer_io_t io,int limit)377 hammer_io_read(struct vnode *devvp, hammer_io_t io, int limit)
378 {
379 struct buf *bp;
380 int error;
381
382 if ((bp = io->bp) == NULL) {
383 int hce = hammer_cluster_enable;
384
385 atomic_add_long(&hammer_count_io_running_read, io->bytes);
386 if (hce && limit > io->bytes) {
387 error = cluster_read(devvp, io->offset + limit,
388 io->offset, io->bytes,
389 HAMMER_CLUSTER_SIZE,
390 HAMMER_CLUSTER_SIZE * hce,
391 &io->bp);
392 } else {
393 error = bread(devvp, io->offset, io->bytes, &io->bp);
394 }
395 hammer_stats_disk_read += io->bytes;
396 atomic_add_long(&hammer_count_io_running_read, -io->bytes);
397
398 /*
399 * The code generally assumes b_ops/b_dep has been set-up,
400 * even if we error out here.
401 */
402 bp = io->bp;
403 if ((hammer_debug_io & 0x0001) && (bp->b_flags & B_IOISSUED)) {
404 hdkprintf("zone2_offset %016jx %s\n",
405 (intmax_t)bp->b_bio2.bio_offset,
406 hammer_io_to_iostring(io));
407 }
408 bp->b_flags &= ~B_IOISSUED;
409 bp->b_ops = &hammer_bioops;
410
411 hammer_buf_attach_io(bp, io); /* locked by the io lock */
412 BUF_KERNPROC(bp);
413 KKASSERT(io->modified == 0);
414 KKASSERT(io->running == 0);
415 KKASSERT(io->waiting == 0);
416 io->released = 0; /* we hold an active lock on bp */
417 } else {
418 error = 0;
419 }
420 return(error);
421 }
422
423 /*
424 * Similar to hammer_io_read() but returns a zero'd out buffer instead.
425 * Must be called with the IO exclusively locked.
426 *
427 * vfs_bio_clrbuf() is kinda nasty, enforce serialization against background
428 * I/O by forcing the buffer to not be in a released state before calling
429 * it.
430 *
431 * This function will also mark the IO as modified but it will not
432 * increment the modify_refs count.
433 *
434 * No I/O callbacks can occur while we hold the buffer locked.
435 */
436 int
hammer_io_new(struct vnode * devvp,hammer_io_t io)437 hammer_io_new(struct vnode *devvp, hammer_io_t io)
438 {
439 struct buf *bp;
440
441 if ((bp = io->bp) == NULL) {
442 io->bp = getblk(devvp, io->offset, io->bytes, 0, 0);
443 bp = io->bp;
444 bp->b_ops = &hammer_bioops;
445
446 hammer_buf_attach_io(bp, io); /* locked by the io lock */
447 io->released = 0;
448 KKASSERT(io->running == 0);
449 io->waiting = 0;
450 BUF_KERNPROC(bp);
451 } else {
452 if (io->released) {
453 regetblk(bp);
454 BUF_KERNPROC(bp);
455 io->released = 0;
456 }
457 }
458 hammer_io_modify(io, 0);
459 vfs_bio_clrbuf(bp);
460 return(0);
461 }
462
463 /*
464 * Advance the activity count on the underlying buffer because
465 * HAMMER does not getblk/brelse on every access.
466 *
467 * The io->bp cannot go away while the buffer is referenced.
468 */
469 void
hammer_io_advance(hammer_io_t io)470 hammer_io_advance(hammer_io_t io)
471 {
472 if (io->bp)
473 buf_act_advance(io->bp);
474 }
475
476 /*
477 * Remove potential device level aliases against buffers managed by high level
478 * vnodes. Aliases can also be created due to mixed buffer sizes or via
479 * direct access to the backing store device.
480 *
481 * This is nasty because the buffers are also VMIO-backed. Even if a buffer
482 * does not exist its backing VM pages might, and we have to invalidate
483 * those as well or a getblk() will reinstate them.
484 *
485 * Buffer cache buffers associated with hammer_buffers cannot be
486 * invalidated.
487 */
488 int
hammer_io_inval(hammer_volume_t volume,hammer_off_t zone2_offset)489 hammer_io_inval(hammer_volume_t volume, hammer_off_t zone2_offset)
490 {
491 hammer_io_t io;
492 hammer_mount_t hmp;
493 hammer_off_t phys_offset;
494 struct buf *bp;
495 int error;
496
497 hmp = volume->io.hmp;
498 lwkt_gettoken(&hmp->io_token);
499
500 /*
501 * If a device buffer already exists for the specified physical
502 * offset use that, otherwise instantiate a buffer to cover any
503 * related VM pages, set BNOCACHE, and brelse().
504 */
505 phys_offset = hammer_xlate_to_phys(volume->ondisk, zone2_offset);
506 if ((bp = findblk(volume->devvp, phys_offset, 0)) != NULL)
507 bremfree(bp);
508 else
509 bp = getblk(volume->devvp, phys_offset, HAMMER_BUFSIZE, 0, 0);
510
511 if ((io = hammer_buf_peek_io(bp)) != NULL) {
512 #if 0
513 hammer_ref(&io->lock);
514 hammer_io_clear_modify(io, 1);
515 bundirty(bp);
516 io->released = 0;
517 BUF_KERNPROC(bp);
518 io->reclaim = 1;
519 io->waitdep = 1; /* XXX this is a fs_token field */
520 KKASSERT(hammer_isactive(&io->lock) == 1);
521 hammer_rel_buffer(HAMMER_ITOB(io), 0);
522 /*hammer_io_deallocate(bp);*/
523 #endif
524 bqrelse(bp);
525 error = EAGAIN;
526 } else {
527 KKASSERT((bp->b_flags & B_LOCKED) == 0);
528 bundirty(bp);
529 bp->b_flags |= B_NOCACHE|B_RELBUF;
530 brelse(bp);
531 error = 0;
532 }
533 lwkt_reltoken(&hmp->io_token);
534 return(error);
535 }
536
537 /*
538 * This routine is called on the last reference to a hammer structure.
539 * The io must be interlocked with a refcount of zero. The hammer structure
540 * will remain interlocked on return.
541 *
542 * This routine may return a non-NULL bp to the caller for dispoal.
543 * The caller typically brelse()'s the bp.
544 *
545 * The bp may or may not still be passively associated with the IO. It
546 * will remain passively associated if it is unreleasable (e.g. a modified
547 * meta-data buffer).
548 *
549 * The only requirement here is that modified meta-data and volume-header
550 * buffer may NOT be disassociated from the IO structure, and consequently
551 * we also leave such buffers actively associated with the IO if they already
552 * are (since the kernel can't do anything with them anyway). Only the
553 * flusher is allowed to write such buffers out. Modified pure-data and
554 * undo buffers are returned to the kernel but left passively associated
555 * so we can track when the kernel writes the bp out.
556 */
557 struct buf *
hammer_io_release(hammer_io_t io,int flush)558 hammer_io_release(hammer_io_t io, int flush)
559 {
560 struct buf *bp;
561
562 if ((bp = io->bp) == NULL)
563 return(NULL);
564
565 /*
566 * Try to flush a dirty IO to disk if asked to by the
567 * caller or if the kernel tried to flush the buffer in the past.
568 *
569 * Kernel-initiated flushes are only allowed for pure-data buffers.
570 * meta-data and volume buffers can only be flushed explicitly
571 * by HAMMER.
572 */
573 if (io->modified) {
574 if (flush) {
575 hammer_io_flush(io, 0);
576 } else if (bp->b_flags & B_LOCKED) {
577 switch(io->type) {
578 case HAMMER_IOTYPE_DATA_BUFFER:
579 hammer_io_flush(io, 0);
580 break;
581 case HAMMER_IOTYPE_UNDO_BUFFER:
582 hammer_io_flush(io, hammer_undo_reclaim(io));
583 break;
584 default:
585 break;
586 }
587 } /* else no explicit request to flush the buffer */
588 }
589
590 /*
591 * Wait for the IO to complete if asked to. This occurs when
592 * the buffer must be disposed of definitively during an umount
593 * or buffer invalidation.
594 */
595 if (io->waitdep && io->running) {
596 hammer_io_wait(io);
597 }
598
599 /*
600 * Return control of the buffer to the kernel (with the provisio
601 * that our bioops can override kernel decisions with regards to
602 * the buffer).
603 */
604 if ((flush || io->reclaim) && io->modified == 0 && io->running == 0) {
605 /*
606 * Always disassociate the bp if an explicit flush
607 * was requested and the IO completed with no error
608 * (so unmount can really clean up the structure).
609 */
610 if (io->released) {
611 regetblk(bp);
612 BUF_KERNPROC(bp);
613 } else {
614 io->released = 1;
615 }
616 hammer_io_disassociate(io);
617 /* return the bp */
618 } else if (io->modified) {
619 /*
620 * Only certain IO types can be released to the kernel if
621 * the buffer has been modified.
622 *
623 * volume and meta-data IO types may only be explicitly
624 * flushed by HAMMER.
625 */
626 switch(io->type) {
627 case HAMMER_IOTYPE_DATA_BUFFER:
628 case HAMMER_IOTYPE_UNDO_BUFFER:
629 if (io->released == 0) {
630 io->released = 1;
631 bp->b_flags |= B_CLUSTEROK;
632 bdwrite(bp);
633 }
634 break;
635 default:
636 break;
637 }
638 bp = NULL; /* bp left associated */
639 } else if (io->released == 0) {
640 /*
641 * Clean buffers can be generally released to the kernel.
642 * We leave the bp passively associated with the HAMMER
643 * structure and use bioops to disconnect it later on
644 * if the kernel wants to discard the buffer.
645 *
646 * We can steal the structure's ownership of the bp.
647 */
648 io->released = 1;
649 if (bp->b_flags & B_LOCKED) {
650 hammer_io_disassociate(io);
651 /* return the bp */
652 } else {
653 if (io->reclaim) {
654 hammer_io_disassociate(io);
655 /* return the bp */
656 } else {
657 /* return the bp (bp passively associated) */
658 }
659 }
660 } else {
661 /*
662 * A released buffer is passively associate with our
663 * hammer_io structure. The kernel cannot destroy it
664 * without making a bioops call. If the kernel (B_LOCKED)
665 * or we (reclaim) requested that the buffer be destroyed
666 * we destroy it, otherwise we do a quick get/release to
667 * reset its position in the kernel's LRU list.
668 *
669 * Leaving the buffer passively associated allows us to
670 * use the kernel's LRU buffer flushing mechanisms rather
671 * then rolling our own.
672 *
673 * XXX there are two ways of doing this. We can re-acquire
674 * and passively release to reset the LRU, or not.
675 */
676 if (io->running == 0) {
677 regetblk(bp);
678 if ((bp->b_flags & B_LOCKED) || io->reclaim) {
679 hammer_io_disassociate(io);
680 /* return the bp */
681 } else {
682 /* return the bp (bp passively associated) */
683 }
684 } else {
685 /*
686 * bp is left passively associated but we do not
687 * try to reacquire it. Interactions with the io
688 * structure will occur on completion of the bp's
689 * I/O.
690 */
691 bp = NULL;
692 }
693 }
694 return(bp);
695 }
696
697 /*
698 * This routine is called with a locked IO when a flush is desired and
699 * no other references to the structure exists other then ours. This
700 * routine is ONLY called when HAMMER believes it is safe to flush a
701 * potentially modified buffer out.
702 *
703 * The locked io or io reference prevents a flush from being initiated
704 * by the kernel.
705 */
706 void
hammer_io_flush(hammer_io_t io,int reclaim)707 hammer_io_flush(hammer_io_t io, int reclaim)
708 {
709 struct buf *bp;
710 hammer_mount_t hmp;
711
712 /*
713 * Degenerate case - nothing to flush if nothing is dirty.
714 */
715 if (io->modified == 0)
716 return;
717
718 KKASSERT(io->bp);
719 KKASSERT(io->modify_refs <= 0);
720
721 /*
722 * Acquire ownership of the bp, particularly before we clear our
723 * modified flag.
724 *
725 * We are going to bawrite() this bp. Don't leave a window where
726 * io->released is set, we actually own the bp rather then our
727 * buffer.
728 *
729 * The io_token should not be required here as only
730 */
731 hmp = io->hmp;
732 bp = io->bp;
733 if (io->released) {
734 regetblk(bp);
735 /* BUF_KERNPROC(io->bp); */
736 /* io->released = 0; */
737 KKASSERT(io->released);
738 KKASSERT(io->bp == bp);
739 } else {
740 io->released = 1;
741 }
742
743 if (reclaim) {
744 io->reclaim = 1;
745 if ((bp->b_flags & B_LOCKED) == 0) {
746 bp->b_flags |= B_LOCKED;
747 atomic_add_int(&hammer_count_io_locked, 1);
748 }
749 }
750
751 /*
752 * Acquire exclusive access to the bp and then clear the modified
753 * state of the buffer prior to issuing I/O to interlock any
754 * modifications made while the I/O is in progress. This shouldn't
755 * happen anyway but losing data would be worse. The modified bit
756 * will be rechecked after the IO completes.
757 *
758 * NOTE: This call also finalizes the buffer's content (inval == 0).
759 *
760 * This is only legal when lock.refs == 1 (otherwise we might clear
761 * the modified bit while there are still users of the cluster
762 * modifying the data).
763 *
764 * Do this before potentially blocking so any attempt to modify the
765 * ondisk while we are blocked blocks waiting for us.
766 */
767 hammer_ref(&io->lock);
768 hammer_io_clear_modify(io, 0);
769 hammer_rel(&io->lock);
770
771 if (hammer_debug_io & 0x0002)
772 hdkprintf("%016jx\n", bp->b_bio1.bio_offset);
773
774 /*
775 * Transfer ownership to the kernel and initiate I/O.
776 *
777 * NOTE: We do not hold io_token so an atomic op is required to
778 * update io_running_space.
779 */
780 io->running = 1;
781 atomic_add_long(&hmp->io_running_space, io->bytes);
782 atomic_add_long(&hammer_count_io_running_write, io->bytes);
783 lwkt_gettoken(&hmp->io_token);
784 TAILQ_INSERT_TAIL(&hmp->iorun_list, io, iorun_entry);
785 lwkt_reltoken(&hmp->io_token);
786 cluster_awrite(bp);
787 hammer_io_flush_mark(io->volume);
788 }
789
790 /************************************************************************
791 * BUFFER DIRTYING *
792 ************************************************************************
793 *
794 * These routines deal with dependancies created when IO buffers get
795 * modified. The caller must call hammer_modify_*() on a referenced
796 * HAMMER structure prior to modifying its on-disk data.
797 *
798 * Any intent to modify an IO buffer acquires the related bp and imposes
799 * various write ordering dependancies.
800 */
801
802 /*
803 * Mark a HAMMER structure as undergoing modification. Meta-data buffers
804 * are locked until the flusher can deal with them, pure data buffers
805 * can be written out.
806 *
807 * The referenced io prevents races.
808 */
809 static
810 void
hammer_io_modify(hammer_io_t io,int count)811 hammer_io_modify(hammer_io_t io, int count)
812 {
813 /*
814 * io->modify_refs must be >= 0
815 */
816 while (io->modify_refs < 0) {
817 io->waitmod = 1;
818 tsleep(io, 0, "hmrmod", 0);
819 }
820
821 /*
822 * Shortcut if nothing to do.
823 */
824 KKASSERT(hammer_isactive(&io->lock) && io->bp != NULL);
825 io->modify_refs += count;
826 if (io->modified && io->released == 0)
827 return;
828
829 /*
830 * NOTE: It is important not to set the modified bit
831 * until after we have acquired the bp or we risk
832 * racing against checkwrite.
833 */
834 hammer_lock_ex(&io->lock);
835 if (io->released) {
836 regetblk(io->bp);
837 BUF_KERNPROC(io->bp);
838 io->released = 0;
839 }
840 if (io->modified == 0) {
841 hammer_io_set_modlist(io);
842 io->modified = 1;
843 }
844 hammer_unlock(&io->lock);
845 }
846
847 static __inline
848 void
hammer_io_modify_done(hammer_io_t io)849 hammer_io_modify_done(hammer_io_t io)
850 {
851 KKASSERT(io->modify_refs > 0);
852 --io->modify_refs;
853 if (io->modify_refs == 0 && io->waitmod) {
854 io->waitmod = 0;
855 wakeup(io);
856 }
857 }
858
859 /*
860 * The write interlock blocks other threads trying to modify a buffer
861 * (they block in hammer_io_modify()) after us, or blocks us while other
862 * threads are in the middle of modifying a buffer.
863 *
864 * The caller also has a ref on the io, however if we are not careful
865 * we will race bioops callbacks (checkwrite). To deal with this
866 * we must at least acquire and release the io_token, and it is probably
867 * better to hold it through the setting of modify_refs.
868 */
869 void
hammer_io_write_interlock(hammer_io_t io)870 hammer_io_write_interlock(hammer_io_t io)
871 {
872 hammer_mount_t hmp = io->hmp;
873
874 lwkt_gettoken(&hmp->io_token);
875 while (io->modify_refs != 0) {
876 io->waitmod = 1;
877 tsleep(io, 0, "hmrmod", 0);
878 }
879 io->modify_refs = -1;
880 lwkt_reltoken(&hmp->io_token);
881 }
882
883 void
hammer_io_done_interlock(hammer_io_t io)884 hammer_io_done_interlock(hammer_io_t io)
885 {
886 KKASSERT(io->modify_refs == -1);
887 io->modify_refs = 0;
888 if (io->waitmod) {
889 io->waitmod = 0;
890 wakeup(io);
891 }
892 }
893
894 /*
895 * Caller intends to modify a volume's ondisk structure.
896 *
897 * This is only allowed if we are the flusher or we have a ref on the
898 * sync_lock.
899 */
900 void
hammer_modify_volume(hammer_transaction_t trans,hammer_volume_t volume,void * base,int len)901 hammer_modify_volume(hammer_transaction_t trans, hammer_volume_t volume,
902 void *base, int len)
903 {
904 KKASSERT (trans == NULL || trans->sync_lock_refs > 0);
905
906 hammer_io_modify(&volume->io, 1);
907 if (len) {
908 intptr_t rel_offset = (intptr_t)base - (intptr_t)volume->ondisk;
909 KKASSERT((rel_offset & ~(intptr_t)HAMMER_BUFMASK) == 0);
910 hammer_generate_undo(trans,
911 HAMMER_ENCODE_RAW_VOLUME(volume->vol_no, rel_offset),
912 base, len);
913 }
914 }
915
916 /*
917 * Caller intends to modify a buffer's ondisk structure.
918 *
919 * This is only allowed if we are the flusher or we have a ref on the
920 * sync_lock.
921 */
922 void
hammer_modify_buffer(hammer_transaction_t trans,hammer_buffer_t buffer,void * base,int len)923 hammer_modify_buffer(hammer_transaction_t trans, hammer_buffer_t buffer,
924 void *base, int len)
925 {
926 KKASSERT (trans == NULL || trans->sync_lock_refs > 0);
927
928 hammer_io_modify(&buffer->io, 1);
929 if (len) {
930 intptr_t rel_offset = (intptr_t)base - (intptr_t)buffer->ondisk;
931 KKASSERT((rel_offset & ~(intptr_t)HAMMER_BUFMASK) == 0);
932 hammer_generate_undo(trans,
933 buffer->zone2_offset + rel_offset,
934 base, len);
935 }
936 }
937
938 void
hammer_modify_volume_done(hammer_volume_t volume)939 hammer_modify_volume_done(hammer_volume_t volume)
940 {
941 hammer_io_modify_done(&volume->io);
942 }
943
944 void
hammer_modify_buffer_done(hammer_buffer_t buffer)945 hammer_modify_buffer_done(hammer_buffer_t buffer)
946 {
947 hammer_io_modify_done(&buffer->io);
948 }
949
950 /*
951 * Mark an entity as not being dirty any more and finalize any
952 * delayed adjustments to the buffer.
953 *
954 * Delayed adjustments are an important performance enhancement, allowing
955 * us to avoid recalculating B-Tree node CRCs over and over again when
956 * making bulk-modifications to the B-Tree.
957 *
958 * If inval is non-zero delayed adjustments are ignored.
959 *
960 * This routine may dereference related btree nodes and cause the
961 * buffer to be dereferenced. The caller must own a reference on io.
962 */
963 void
hammer_io_clear_modify(hammer_io_t io,int inval)964 hammer_io_clear_modify(hammer_io_t io, int inval)
965 {
966 hammer_mount_t hmp;
967
968 /*
969 * io_token is needed to avoid races on mod_root
970 */
971 if (io->modified == 0)
972 return;
973 hmp = io->hmp;
974 lwkt_gettoken(&hmp->io_token);
975 if (io->modified == 0) {
976 lwkt_reltoken(&hmp->io_token);
977 return;
978 }
979
980 /*
981 * Take us off the mod-list and clear the modified bit.
982 */
983 KKASSERT(io->mod_root != NULL);
984 if (io->mod_root == &io->hmp->volu_root ||
985 io->mod_root == &io->hmp->meta_root) {
986 io->hmp->locked_dirty_space -= io->bytes;
987 atomic_add_long(&hammer_count_dirtybufspace, -io->bytes);
988 }
989 RB_REMOVE(hammer_mod_rb_tree, io->mod_root, io);
990 io->mod_root = NULL;
991 io->modified = 0;
992
993 lwkt_reltoken(&hmp->io_token);
994
995 /*
996 * If this bit is not set there are no delayed adjustments.
997 */
998 if (io->gencrc == 0)
999 return;
1000 io->gencrc = 0;
1001
1002 /*
1003 * Finalize requested CRCs. The NEEDSCRC flag also holds a reference
1004 * on the node (& underlying buffer). Release the node after clearing
1005 * the flag.
1006 */
1007 if (io->type == HAMMER_IOTYPE_META_BUFFER) {
1008 hammer_buffer_t buffer = HAMMER_ITOB(io);
1009 hammer_node_t node;
1010
1011 restart:
1012 TAILQ_FOREACH(node, &buffer->node_list, entry) {
1013 if ((node->flags & HAMMER_NODE_NEEDSCRC) == 0)
1014 continue;
1015 node->flags &= ~HAMMER_NODE_NEEDSCRC;
1016 KKASSERT(node->ondisk);
1017 if (inval == 0)
1018 hammer_crc_set_btree(hmp->version, node->ondisk);
1019 hammer_rel_node(node);
1020 goto restart;
1021 }
1022 }
1023 /* caller must still have ref on io */
1024 KKASSERT(hammer_isactive(&io->lock));
1025 }
1026
1027 /*
1028 * Clear the IO's modify list. Even though the IO is no longer modified
1029 * it may still be on the lose_root. This routine is called just before
1030 * the governing hammer_buffer is destroyed.
1031 *
1032 * mod_root requires io_token protection.
1033 */
1034 void
hammer_io_clear_modlist(hammer_io_t io)1035 hammer_io_clear_modlist(hammer_io_t io)
1036 {
1037 hammer_mount_t hmp = io->hmp;
1038
1039 KKASSERT(io->modified == 0);
1040 if (io->mod_root) {
1041 lwkt_gettoken(&hmp->io_token);
1042 if (io->mod_root) {
1043 KKASSERT(io->mod_root == &io->hmp->lose_root);
1044 RB_REMOVE(hammer_mod_rb_tree, io->mod_root, io);
1045 io->mod_root = NULL;
1046 }
1047 lwkt_reltoken(&hmp->io_token);
1048 }
1049 }
1050
1051 static void
hammer_io_set_modlist(hammer_io_t io)1052 hammer_io_set_modlist(hammer_io_t io)
1053 {
1054 hammer_mount_t hmp = io->hmp;
1055
1056 lwkt_gettoken(&hmp->io_token);
1057 KKASSERT(io->mod_root == NULL);
1058
1059 switch(io->type) {
1060 case HAMMER_IOTYPE_VOLUME:
1061 io->mod_root = &hmp->volu_root;
1062 hmp->locked_dirty_space += io->bytes;
1063 atomic_add_long(&hammer_count_dirtybufspace, io->bytes);
1064 break;
1065 case HAMMER_IOTYPE_META_BUFFER:
1066 io->mod_root = &hmp->meta_root;
1067 hmp->locked_dirty_space += io->bytes;
1068 atomic_add_long(&hammer_count_dirtybufspace, io->bytes);
1069 break;
1070 case HAMMER_IOTYPE_UNDO_BUFFER:
1071 io->mod_root = &hmp->undo_root;
1072 break;
1073 case HAMMER_IOTYPE_DATA_BUFFER:
1074 io->mod_root = &hmp->data_root;
1075 break;
1076 case HAMMER_IOTYPE_DUMMY:
1077 hpanic("bad io type");
1078 break; /* NOT REACHED */
1079 }
1080 if (RB_INSERT(hammer_mod_rb_tree, io->mod_root, io)) {
1081 hpanic("duplicate entry @ %d:%015jx",
1082 io->volume->vol_no, io->offset);
1083 /* NOT REACHED */
1084 }
1085 lwkt_reltoken(&hmp->io_token);
1086 }
1087
1088 /************************************************************************
1089 * HAMMER_BIOOPS *
1090 ************************************************************************
1091 *
1092 */
1093
1094 /*
1095 * Pre-IO initiation kernel callback - cluster build only
1096 *
1097 * bioops callback - hold io_token
1098 */
1099 static void
hammer_io_start(struct buf * bp)1100 hammer_io_start(struct buf *bp)
1101 {
1102 /* nothing to do, so io_token not needed */
1103 }
1104
1105 /*
1106 * Post-IO completion kernel callback - MAY BE CALLED FROM INTERRUPT!
1107 *
1108 * NOTE: HAMMER may modify a data buffer after we have initiated write
1109 * I/O.
1110 *
1111 * NOTE: MPSAFE callback
1112 *
1113 * bioops callback - hold io_token
1114 */
1115 static void
hammer_io_complete(struct buf * bp)1116 hammer_io_complete(struct buf *bp)
1117 {
1118 hammer_io_t io = hammer_buf_peek_io(bp);
1119 hammer_mount_t hmp = io->hmp;
1120 hammer_io_t ionext;
1121
1122 lwkt_gettoken(&hmp->io_token);
1123
1124 KKASSERT(io->released == 1);
1125
1126 /*
1127 * Deal with people waiting for I/O to drain
1128 */
1129 if (io->running) {
1130 /*
1131 * Deal with critical write errors. Once a critical error
1132 * has been flagged in hmp the UNDO FIFO will not be updated.
1133 * That way crash recover will give us a consistent
1134 * filesystem.
1135 *
1136 * Because of this we can throw away failed UNDO buffers. If
1137 * we throw away META or DATA buffers we risk corrupting
1138 * the now read-only version of the filesystem visible to
1139 * the user. Clear B_ERROR so the buffer is not re-dirtied
1140 * by the kernel and ref the io so it doesn't get thrown
1141 * away.
1142 */
1143 if (bp->b_flags & B_ERROR) {
1144 lwkt_gettoken(&hmp->fs_token);
1145 hammer_critical_error(hmp, NULL, bp->b_error,
1146 "while flushing meta-data");
1147 lwkt_reltoken(&hmp->fs_token);
1148
1149 switch(io->type) {
1150 case HAMMER_IOTYPE_UNDO_BUFFER:
1151 break;
1152 default:
1153 if (io->ioerror == 0) {
1154 io->ioerror = 1;
1155 hammer_ref(&io->lock);
1156 }
1157 break;
1158 }
1159 bp->b_flags &= ~B_ERROR;
1160 bundirty(bp);
1161 #if 0
1162 hammer_io_set_modlist(io);
1163 io->modified = 1;
1164 #endif
1165 }
1166 hammer_stats_disk_write += io->bytes;
1167 atomic_add_long(&hammer_count_io_running_write, -io->bytes);
1168 atomic_add_long(&hmp->io_running_space, -io->bytes);
1169 KKASSERT(hmp->io_running_space >= 0);
1170 io->running = 0;
1171
1172 /*
1173 * Remove from iorun list and wakeup any multi-io waiter(s).
1174 */
1175 if (TAILQ_FIRST(&hmp->iorun_list) == io) {
1176 ionext = TAILQ_NEXT(io, iorun_entry);
1177 if (ionext && ionext->type == HAMMER_IOTYPE_DUMMY)
1178 wakeup(ionext);
1179 }
1180 TAILQ_REMOVE(&hmp->iorun_list, io, iorun_entry);
1181 } else {
1182 hammer_stats_disk_read += io->bytes;
1183 }
1184
1185 if (io->waiting) {
1186 io->waiting = 0;
1187 wakeup(io);
1188 }
1189
1190 /*
1191 * If B_LOCKED is set someone wanted to deallocate the bp at some
1192 * point, try to do it now. The operation will fail if there are
1193 * refs or if hammer_io_deallocate() is unable to gain the
1194 * interlock.
1195 */
1196 if (bp->b_flags & B_LOCKED) {
1197 atomic_add_int(&hammer_count_io_locked, -1);
1198 bp->b_flags &= ~B_LOCKED;
1199 hammer_io_deallocate(bp);
1200 /* structure may be dead now */
1201 }
1202 lwkt_reltoken(&hmp->io_token);
1203 }
1204
1205 /*
1206 * Callback from kernel when it wishes to deallocate a passively
1207 * associated structure. This mostly occurs with clean buffers
1208 * but it may be possible for a holding structure to be marked dirty
1209 * while its buffer is passively associated. The caller owns the bp.
1210 *
1211 * If we cannot disassociate we set B_LOCKED to prevent the buffer
1212 * from getting reused.
1213 *
1214 * WARNING: Because this can be called directly by getnewbuf we cannot
1215 * recurse into the tree. If a bp cannot be immediately disassociated
1216 * our only recourse is to set B_LOCKED.
1217 *
1218 * WARNING: This may be called from an interrupt via hammer_io_complete()
1219 *
1220 * bioops callback - hold io_token
1221 */
1222 static void
hammer_io_deallocate(struct buf * bp)1223 hammer_io_deallocate(struct buf *bp)
1224 {
1225 hammer_io_t io = hammer_buf_peek_io(bp);
1226 hammer_mount_t hmp;
1227
1228 hmp = io->hmp;
1229
1230 lwkt_gettoken(&hmp->io_token);
1231
1232 KKASSERT((bp->b_flags & B_LOCKED) == 0 && io->running == 0);
1233 if (hammer_try_interlock_norefs(&io->lock) == 0) {
1234 /*
1235 * We cannot safely disassociate a bp from a referenced
1236 * or interlocked HAMMER structure.
1237 */
1238 bp->b_flags |= B_LOCKED;
1239 atomic_add_int(&hammer_count_io_locked, 1);
1240 } else if (io->modified) {
1241 /*
1242 * It is not legal to disassociate a modified buffer. This
1243 * case really shouldn't ever occur.
1244 */
1245 bp->b_flags |= B_LOCKED;
1246 atomic_add_int(&hammer_count_io_locked, 1);
1247 hammer_put_interlock(&io->lock, 0);
1248 } else {
1249 /*
1250 * Disassociate the BP. If the io has no refs left we
1251 * have to add it to the loose list. The kernel has
1252 * locked the buffer and therefore our io must be
1253 * in a released state.
1254 */
1255 hammer_io_disassociate(io);
1256 if (io->type != HAMMER_IOTYPE_VOLUME) {
1257 KKASSERT(io->bp == NULL);
1258 KKASSERT(io->mod_root == NULL);
1259 io->mod_root = &hmp->lose_root;
1260 if (RB_INSERT(hammer_mod_rb_tree, io->mod_root, io)) {
1261 hpanic("duplicate entry @ %d:%015jx",
1262 io->volume->vol_no, io->offset);
1263 /* NOT REACHED */
1264 }
1265 }
1266 hammer_put_interlock(&io->lock, 1);
1267 }
1268 lwkt_reltoken(&hmp->io_token);
1269 }
1270
1271 /*
1272 * bioops callback - hold io_token
1273 */
1274 static int
hammer_io_fsync(struct vnode * vp)1275 hammer_io_fsync(struct vnode *vp)
1276 {
1277 /* nothing to do, so io_token not needed */
1278 return(0);
1279 }
1280
1281 /*
1282 * NOTE: will not be called unless we tell the kernel about the
1283 * bioops. Unused... we use the mount's VFS_SYNC instead.
1284 *
1285 * bioops callback - hold io_token
1286 */
1287 static int
hammer_io_sync(struct mount * mp)1288 hammer_io_sync(struct mount *mp)
1289 {
1290 /* nothing to do, so io_token not needed */
1291 return(0);
1292 }
1293
1294 /*
1295 * bioops callback - hold io_token
1296 */
1297 static void
hammer_io_movedeps(struct buf * bp1,struct buf * bp2)1298 hammer_io_movedeps(struct buf *bp1, struct buf *bp2)
1299 {
1300 /* nothing to do, so io_token not needed */
1301 }
1302
1303 /*
1304 * I/O pre-check for reading and writing. HAMMER only uses this for
1305 * B_CACHE buffers so checkread just shouldn't happen, but if it does
1306 * allow it.
1307 *
1308 * Writing is a different case. We don't want the kernel to try to write
1309 * out a buffer that HAMMER may be modifying passively or which has a
1310 * dependancy. In addition, kernel-demanded writes can only proceed for
1311 * certain types of buffers (i.e. UNDO and DATA types). Other dirty
1312 * buffer types can only be explicitly written by the flusher.
1313 *
1314 * checkwrite will only be called for bdwrite()n buffers. If we return
1315 * success the kernel is guaranteed to initiate the buffer write.
1316 *
1317 * bioops callback - hold io_token
1318 */
1319 static int
hammer_io_checkread(struct buf * bp)1320 hammer_io_checkread(struct buf *bp)
1321 {
1322 /* nothing to do, so io_token not needed */
1323 return(0);
1324 }
1325
1326 /*
1327 * The kernel is asking us whether it can write out a dirty buffer or not.
1328 *
1329 * bioops callback - hold io_token
1330 */
1331 static int
hammer_io_checkwrite(struct buf * bp)1332 hammer_io_checkwrite(struct buf *bp)
1333 {
1334 hammer_io_t io = hammer_buf_peek_io(bp);
1335 hammer_mount_t hmp = io->hmp;
1336
1337 /*
1338 * This shouldn't happen under normal operation.
1339 */
1340 lwkt_gettoken(&hmp->io_token);
1341 if (io->type == HAMMER_IOTYPE_VOLUME ||
1342 io->type == HAMMER_IOTYPE_META_BUFFER) {
1343 if (!panicstr)
1344 hpanic("illegal buffer");
1345 if ((bp->b_flags & B_LOCKED) == 0) {
1346 bp->b_flags |= B_LOCKED;
1347 atomic_add_int(&hammer_count_io_locked, 1);
1348 }
1349 lwkt_reltoken(&hmp->io_token);
1350 return(1);
1351 }
1352
1353 /*
1354 * We have to be able to interlock the IO to safely modify any
1355 * of its fields without holding the fs_token. If we can't lock
1356 * it then we are racing someone.
1357 *
1358 * Our ownership of the bp lock prevents the io from being ripped
1359 * out from under us.
1360 */
1361 if (hammer_try_interlock_norefs(&io->lock) == 0) {
1362 bp->b_flags |= B_LOCKED;
1363 atomic_add_int(&hammer_count_io_locked, 1);
1364 lwkt_reltoken(&hmp->io_token);
1365 return(1);
1366 }
1367
1368 /*
1369 * The modified bit must be cleared prior to the initiation of
1370 * any IO (returning 0 initiates the IO). Because this is a
1371 * normal data buffer hammer_io_clear_modify() runs through a
1372 * simple degenerate case.
1373 *
1374 * Return 0 will cause the kernel to initiate the IO, and we
1375 * must normally clear the modified bit before we begin. If
1376 * the io has modify_refs we do not clear the modified bit,
1377 * otherwise we may miss changes.
1378 *
1379 * Only data and undo buffers can reach here. These buffers do
1380 * not have terminal crc functions but we temporarily reference
1381 * the IO anyway, just in case.
1382 */
1383 if (io->modify_refs == 0 && io->modified) {
1384 hammer_ref(&io->lock);
1385 hammer_io_clear_modify(io, 0);
1386 hammer_rel(&io->lock);
1387 } else if (io->modified) {
1388 KKASSERT(io->type == HAMMER_IOTYPE_DATA_BUFFER);
1389 }
1390
1391 /*
1392 * The kernel is going to start the IO, set io->running.
1393 */
1394 KKASSERT(io->running == 0);
1395 io->running = 1;
1396 atomic_add_long(&io->hmp->io_running_space, io->bytes);
1397 atomic_add_long(&hammer_count_io_running_write, io->bytes);
1398 TAILQ_INSERT_TAIL(&io->hmp->iorun_list, io, iorun_entry);
1399
1400 hammer_put_interlock(&io->lock, 1);
1401 lwkt_reltoken(&hmp->io_token);
1402
1403 return(0);
1404 }
1405
1406 /*
1407 * Return non-zero if we wish to delay the kernel's attempt to flush
1408 * this buffer to disk.
1409 *
1410 * bioops callback - hold io_token
1411 */
1412 static int
hammer_io_countdeps(struct buf * bp,int n)1413 hammer_io_countdeps(struct buf *bp, int n)
1414 {
1415 /* nothing to do, so io_token not needed */
1416 return(0);
1417 }
1418
1419 static struct bio_ops hammer_bioops = {
1420 .io_start = hammer_io_start,
1421 .io_complete = hammer_io_complete,
1422 .io_deallocate = hammer_io_deallocate,
1423 .io_fsync = hammer_io_fsync,
1424 .io_sync = hammer_io_sync,
1425 .io_movedeps = hammer_io_movedeps,
1426 .io_countdeps = hammer_io_countdeps,
1427 .io_checkread = hammer_io_checkread,
1428 .io_checkwrite = hammer_io_checkwrite,
1429 };
1430
1431 /************************************************************************
1432 * DIRECT IO OPS *
1433 ************************************************************************
1434 *
1435 * These functions operate directly on the buffer cache buffer associated
1436 * with a front-end vnode rather then a back-end device vnode.
1437 */
1438
1439 /*
1440 * Read a buffer associated with a front-end vnode directly from the
1441 * disk media. The bio may be issued asynchronously. If leaf is non-NULL
1442 * we validate the CRC.
1443 *
1444 * We must check for the presence of a HAMMER buffer to handle the case
1445 * where the reblocker has rewritten the data (which it does via the HAMMER
1446 * buffer system, not via the high-level vnode buffer cache), but not yet
1447 * committed the buffer to the media.
1448 */
1449 int
hammer_io_direct_read(hammer_mount_t hmp,struct bio * bio,hammer_btree_leaf_elm_t leaf)1450 hammer_io_direct_read(hammer_mount_t hmp, struct bio *bio,
1451 hammer_btree_leaf_elm_t leaf)
1452 {
1453 hammer_off_t buf_offset;
1454 hammer_off_t zone2_offset;
1455 hammer_volume_t volume;
1456 struct buf *bp;
1457 struct bio *nbio;
1458 int vol_no;
1459 int error;
1460
1461 buf_offset = bio->bio_offset;
1462 KKASSERT(hammer_is_zone_large_data(buf_offset));
1463
1464 /*
1465 * The buffer cache may have an aliased buffer (the reblocker can
1466 * write them). If it does we have to sync any dirty data before
1467 * we can build our direct-read. This is a non-critical code path.
1468 */
1469 bp = bio->bio_buf;
1470 hammer_sync_buffers(hmp, buf_offset, bp->b_bufsize);
1471
1472 /*
1473 * Resolve to a zone-2 offset. The conversion just requires
1474 * munging the top 4 bits but we want to abstract it anyway
1475 * so the blockmap code can verify the zone assignment.
1476 */
1477 zone2_offset = hammer_blockmap_lookup(hmp, buf_offset, &error);
1478 if (error)
1479 goto done;
1480 KKASSERT(hammer_is_zone_raw_buffer(zone2_offset));
1481
1482 /*
1483 * Resolve volume and raw-offset for 3rd level bio. The
1484 * offset will be specific to the volume.
1485 */
1486 vol_no = HAMMER_VOL_DECODE(zone2_offset);
1487 volume = hammer_get_volume(hmp, vol_no, &error);
1488 if (error == 0 && zone2_offset >= volume->maxbuf_off)
1489 error = EIO;
1490
1491 if (error == 0) {
1492 /*
1493 * 3rd level bio (the caller has already pushed once)
1494 */
1495 nbio = push_bio(bio);
1496 nbio->bio_offset = hammer_xlate_to_phys(volume->ondisk,
1497 zone2_offset);
1498 hammer_stats_disk_read += bp->b_bufsize;
1499 vn_strategy(volume->devvp, nbio);
1500 }
1501 hammer_rel_volume(volume, 0);
1502 done:
1503 if (error) {
1504 hdkprintf("failed @ %016jx\n", (intmax_t)zone2_offset);
1505 bp->b_error = error;
1506 bp->b_flags |= B_ERROR;
1507 biodone(bio);
1508 }
1509 return(error);
1510 }
1511
1512 /*
1513 * This works similarly to hammer_io_direct_read() except instead of
1514 * directly reading from the device into the bio we instead indirectly
1515 * read through the device's buffer cache and then copy the data into
1516 * the bio.
1517 *
1518 * If leaf is non-NULL and validation is enabled, the CRC will be checked.
1519 *
1520 * This routine also executes asynchronously. It allows hammer strategy
1521 * calls to operate asynchronously when in double_buffer mode (in addition
1522 * to operating asynchronously when in normal mode).
1523 */
1524 int
hammer_io_indirect_read(hammer_mount_t hmp,struct bio * bio,hammer_btree_leaf_elm_t leaf)1525 hammer_io_indirect_read(hammer_mount_t hmp, struct bio *bio,
1526 hammer_btree_leaf_elm_t leaf)
1527 {
1528 hammer_off_t buf_offset;
1529 hammer_off_t zone2_offset;
1530 hammer_volume_t volume;
1531 struct buf *bp;
1532 int vol_no;
1533 int error;
1534
1535 buf_offset = bio->bio_offset;
1536 KKASSERT(hammer_is_zone_large_data(buf_offset));
1537
1538 /*
1539 * The buffer cache may have an aliased buffer (the reblocker can
1540 * write them). If it does we have to sync any dirty data before
1541 * we can build our direct-read. This is a non-critical code path.
1542 */
1543 bp = bio->bio_buf;
1544 hammer_sync_buffers(hmp, buf_offset, bp->b_bufsize);
1545
1546 /*
1547 * Resolve to a zone-2 offset. The conversion just requires
1548 * munging the top 4 bits but we want to abstract it anyway
1549 * so the blockmap code can verify the zone assignment.
1550 */
1551 zone2_offset = hammer_blockmap_lookup(hmp, buf_offset, &error);
1552 if (error)
1553 goto done;
1554 KKASSERT(hammer_is_zone_raw_buffer(zone2_offset));
1555
1556 /*
1557 * Resolve volume and raw-offset for 3rd level bio. The
1558 * offset will be specific to the volume.
1559 */
1560 vol_no = HAMMER_VOL_DECODE(zone2_offset);
1561 volume = hammer_get_volume(hmp, vol_no, &error);
1562 if (error == 0 && zone2_offset >= volume->maxbuf_off)
1563 error = EIO;
1564
1565 if (error == 0) {
1566 /*
1567 * Convert to the raw volume->devvp offset and acquire
1568 * the buf, issuing async I/O if necessary.
1569 */
1570 hammer_off_t limit;
1571 int hce;
1572
1573 buf_offset = hammer_xlate_to_phys(volume->ondisk, zone2_offset);
1574
1575 if (leaf && hammer_verify_data) {
1576 bio->bio_caller_info1.uvalue32 = leaf->data_crc;
1577 bio->bio_caller_info2.index = 1;
1578 } else {
1579 bio->bio_caller_info2.index = 0;
1580 }
1581 bio->bio_caller_info3.ptr = hmp;
1582
1583 hce = hammer_cluster_enable;
1584 if (hce > 0) {
1585 limit = HAMMER_BIGBLOCK_DOALIGN(zone2_offset);
1586 limit -= zone2_offset;
1587 cluster_readcb(volume->devvp, limit, buf_offset,
1588 bp->b_bufsize,
1589 B_NOTMETA,
1590 HAMMER_CLUSTER_SIZE,
1591 HAMMER_CLUSTER_SIZE * hce,
1592 hammer_indirect_callback,
1593 bio);
1594 } else {
1595 breadcb(volume->devvp, buf_offset, bp->b_bufsize,
1596 B_NOTMETA,
1597 hammer_indirect_callback, bio);
1598 }
1599 }
1600 hammer_rel_volume(volume, 0);
1601 done:
1602 if (error) {
1603 hdkprintf("failed @ %016jx\n", (intmax_t)zone2_offset);
1604 bp->b_error = error;
1605 bp->b_flags |= B_ERROR;
1606 biodone(bio);
1607 }
1608 return(error);
1609 }
1610
1611 /*
1612 * Indirect callback on completion. bio/bp specify the device-backed
1613 * buffer. bio->bio_caller_info1.ptr holds obio.
1614 *
1615 * obio/obp is the original regular file buffer. obio->bio_caller_info*
1616 * contains the crc specification.
1617 *
1618 * We are responsible for calling bpdone() and bqrelse() on bio/bp, and
1619 * for calling biodone() on obio.
1620 */
1621 static void
hammer_indirect_callback(struct bio * bio)1622 hammer_indirect_callback(struct bio *bio)
1623 {
1624 struct buf *bp = bio->bio_buf;
1625 struct buf *obp;
1626 struct bio *obio;
1627 hammer_mount_t hmp;
1628
1629 /*
1630 * If BIO_DONE is already set the device buffer was already
1631 * fully valid (B_CACHE). If it is not set then I/O was issued
1632 * and we have to run I/O completion as the last bio.
1633 *
1634 * Nobody is waiting for our device I/O to complete, we are
1635 * responsible for bqrelse()ing it which means we also have to do
1636 * the equivalent of biowait() and clear BIO_DONE (which breadcb()
1637 * may have set).
1638 *
1639 * Any preexisting device buffer should match the requested size,
1640 * but due to big-block recycling and other factors there is some
1641 * fragility there, so we assert that the device buffer covers
1642 * the request.
1643 */
1644 if ((bio->bio_flags & BIO_DONE) == 0)
1645 bpdone(bp, 0);
1646 bio->bio_flags &= ~(BIO_DONE | BIO_SYNC);
1647
1648 obio = bio->bio_caller_info1.ptr;
1649 obp = obio->bio_buf;
1650 hmp = obio->bio_caller_info3.ptr;
1651
1652 if (bp->b_flags & B_ERROR) {
1653 /*
1654 * Error from block device
1655 */
1656 obp->b_flags |= B_ERROR;
1657 obp->b_error = bp->b_error;
1658 } else if (obio->bio_caller_info2.index &&
1659 obio->bio_caller_info1.uvalue32 !=
1660 hammer_datacrc(hmp->version,
1661 bp->b_data, obp->b_bufsize) &&
1662 obio->bio_caller_info1.uvalue32 !=
1663 hammer_datacrc(HAMMER_VOL_VERSION_SIX,
1664 bp->b_data, obp->b_bufsize)) {
1665 /*
1666 * CRC error. First check against current hammer version,
1667 * then back-off and check against version 6 (the original
1668 * crc).
1669 */
1670 obp->b_flags |= B_ERROR;
1671 obp->b_error = EIO;
1672 } else {
1673 /*
1674 * Everything is ok
1675 */
1676 KKASSERT(bp->b_bufsize >= obp->b_bufsize);
1677 bcopy(bp->b_data, obp->b_data, obp->b_bufsize);
1678 obp->b_resid = 0;
1679 obp->b_flags |= B_AGE;
1680 }
1681 biodone(obio);
1682 bqrelse(bp);
1683 }
1684
1685 /*
1686 * Write a buffer associated with a front-end vnode directly to the
1687 * disk media. The bio may be issued asynchronously.
1688 *
1689 * The BIO is associated with the specified record and RECG_DIRECT_IO
1690 * is set. The recorded is added to its object.
1691 */
1692 int
hammer_io_direct_write(hammer_mount_t hmp,struct bio * bio,hammer_record_t record)1693 hammer_io_direct_write(hammer_mount_t hmp, struct bio *bio,
1694 hammer_record_t record)
1695 {
1696 hammer_btree_leaf_elm_t leaf = &record->leaf;
1697 hammer_off_t buf_offset;
1698 hammer_off_t zone2_offset;
1699 hammer_volume_t volume;
1700 hammer_buffer_t buffer;
1701 struct buf *bp;
1702 struct bio *nbio;
1703 char *ptr;
1704 int vol_no;
1705 int error;
1706
1707 buf_offset = leaf->data_offset;
1708
1709 KKASSERT(hammer_is_zone_record(buf_offset));
1710 KKASSERT(bio->bio_buf->b_cmd == BUF_CMD_WRITE);
1711
1712 /*
1713 * Issue or execute the I/O. The new memory record must replace
1714 * the old one before the I/O completes, otherwise a reaquisition of
1715 * the buffer will load the old media data instead of the new.
1716 */
1717 if ((buf_offset & HAMMER_BUFMASK) == 0 &&
1718 leaf->data_len >= HAMMER_BUFSIZE) {
1719 /*
1720 * We are using the vnode's bio to write directly to the
1721 * media, any hammer_buffer at the same zone-X offset will
1722 * now have stale data.
1723 */
1724 zone2_offset = hammer_blockmap_lookup(hmp, buf_offset, &error);
1725 vol_no = HAMMER_VOL_DECODE(zone2_offset);
1726 volume = hammer_get_volume(hmp, vol_no, &error);
1727
1728 if (error == 0 && zone2_offset >= volume->maxbuf_off)
1729 error = EIO;
1730 if (error == 0) {
1731 bp = bio->bio_buf;
1732 KKASSERT((bp->b_bufsize & HAMMER_BUFMASK) == 0);
1733
1734 /*
1735 * Second level bio - cached zone2 offset.
1736 *
1737 * (We can put our bio_done function in either the
1738 * 2nd or 3rd level).
1739 */
1740 nbio = push_bio(bio);
1741 nbio->bio_offset = zone2_offset;
1742 nbio->bio_done = hammer_io_direct_write_complete;
1743 nbio->bio_caller_info1.ptr = record;
1744 record->zone2_offset = zone2_offset;
1745 record->gflags |= HAMMER_RECG_DIRECT_IO |
1746 HAMMER_RECG_DIRECT_INVAL;
1747
1748 /*
1749 * Third level bio - raw offset specific to the
1750 * correct volume.
1751 */
1752 nbio = push_bio(nbio);
1753 nbio->bio_offset = hammer_xlate_to_phys(volume->ondisk,
1754 zone2_offset);
1755 hammer_stats_disk_write += bp->b_bufsize;
1756 hammer_ip_replace_bulk(hmp, record);
1757 vn_strategy(volume->devvp, nbio);
1758 hammer_io_flush_mark(volume);
1759 }
1760 hammer_rel_volume(volume, 0);
1761 } else {
1762 /*
1763 * Must fit in a standard HAMMER buffer. In this case all
1764 * consumers use the HAMMER buffer system and RECG_DIRECT_IO
1765 * does not need to be set-up.
1766 */
1767 KKASSERT(((buf_offset ^ (buf_offset + leaf->data_len - 1)) & ~HAMMER_BUFMASK64) == 0);
1768 buffer = NULL;
1769 ptr = hammer_bread(hmp, buf_offset, &error, &buffer);
1770 if (error == 0) {
1771 bp = bio->bio_buf;
1772 bp->b_flags |= B_AGE;
1773 hammer_io_modify(&buffer->io, 1);
1774 bcopy(bp->b_data, ptr, leaf->data_len);
1775 hammer_io_modify_done(&buffer->io);
1776 hammer_rel_buffer(buffer, 0);
1777 bp->b_resid = 0;
1778 hammer_ip_replace_bulk(hmp, record);
1779 biodone(bio);
1780 }
1781 }
1782 if (error) {
1783 /*
1784 * Major suckage occured. Also note: The record was
1785 * never added to the tree so we do not have to worry
1786 * about the backend.
1787 */
1788 hdkprintf("failed @ %016jx\n", (intmax_t)leaf->data_offset);
1789 bp = bio->bio_buf;
1790 bp->b_resid = 0;
1791 bp->b_error = EIO;
1792 bp->b_flags |= B_ERROR;
1793 biodone(bio);
1794 record->flags |= HAMMER_RECF_DELETED_FE;
1795 hammer_rel_mem_record(record);
1796 }
1797 return(error);
1798 }
1799
1800 /*
1801 * On completion of the BIO this callback must disconnect
1802 * it from the hammer_record and chain to the previous bio.
1803 *
1804 * An I/O error forces the mount to read-only. Data buffers
1805 * are not B_LOCKED like meta-data buffers are, so we have to
1806 * throw the buffer away to prevent the kernel from retrying.
1807 *
1808 * NOTE: MPSAFE callback, only modify fields we have explicit
1809 * access to (the bp and the record->gflags).
1810 */
1811 static
1812 void
hammer_io_direct_write_complete(struct bio * nbio)1813 hammer_io_direct_write_complete(struct bio *nbio)
1814 {
1815 struct bio *obio;
1816 struct buf *bp;
1817 hammer_record_t record;
1818 hammer_mount_t hmp;
1819
1820 record = nbio->bio_caller_info1.ptr;
1821 KKASSERT(record != NULL);
1822 hmp = record->ip->hmp;
1823
1824 lwkt_gettoken(&hmp->io_token);
1825
1826 bp = nbio->bio_buf;
1827 obio = pop_bio(nbio);
1828 if (bp->b_flags & B_ERROR) {
1829 lwkt_gettoken(&hmp->fs_token);
1830 hammer_critical_error(hmp, record->ip, bp->b_error,
1831 "while writing bulk data");
1832 lwkt_reltoken(&hmp->fs_token);
1833 bp->b_flags |= B_INVAL;
1834 }
1835
1836 KKASSERT(record->gflags & HAMMER_RECG_DIRECT_IO);
1837 if (record->gflags & HAMMER_RECG_DIRECT_WAIT) {
1838 record->gflags &= ~(HAMMER_RECG_DIRECT_IO |
1839 HAMMER_RECG_DIRECT_WAIT);
1840 /* record can disappear once DIRECT_IO flag is cleared */
1841 wakeup(&record->flags);
1842 } else {
1843 record->gflags &= ~HAMMER_RECG_DIRECT_IO;
1844 /* record can disappear once DIRECT_IO flag is cleared */
1845 }
1846
1847 lwkt_reltoken(&hmp->io_token);
1848
1849 biodone(obio);
1850 }
1851
1852
1853 /*
1854 * This is called before a record is either committed to the B-Tree
1855 * or destroyed, to resolve any associated direct-IO.
1856 *
1857 * (1) We must wait for any direct-IO related to the record to complete.
1858 *
1859 * (2) We must remove any buffer cache aliases for data accessed via
1860 * leaf->data_offset or zone2_offset so non-direct-IO consumers
1861 * (the mirroring and reblocking code) do not see stale data.
1862 */
1863 void
hammer_io_direct_wait(hammer_record_t record)1864 hammer_io_direct_wait(hammer_record_t record)
1865 {
1866 hammer_mount_t hmp = record->ip->hmp;
1867
1868 /*
1869 * Wait for I/O to complete
1870 */
1871 if (record->gflags & HAMMER_RECG_DIRECT_IO) {
1872 lwkt_gettoken(&hmp->io_token);
1873 while (record->gflags & HAMMER_RECG_DIRECT_IO) {
1874 record->gflags |= HAMMER_RECG_DIRECT_WAIT;
1875 tsleep(&record->flags, 0, "hmdiow", 0);
1876 }
1877 lwkt_reltoken(&hmp->io_token);
1878 }
1879
1880 /*
1881 * Invalidate any related buffer cache aliases associated with the
1882 * backing device. This is needed because the buffer cache buffer
1883 * for file data is associated with the file vnode, not the backing
1884 * device vnode.
1885 *
1886 * XXX I do not think this case can occur any more now that
1887 * reservations ensure that all such buffers are removed before
1888 * an area can be reused.
1889 */
1890 if (record->gflags & HAMMER_RECG_DIRECT_INVAL) {
1891 KKASSERT(record->leaf.data_offset);
1892 hammer_del_buffers(hmp, record->leaf.data_offset,
1893 record->zone2_offset, record->leaf.data_len,
1894 1);
1895 record->gflags &= ~HAMMER_RECG_DIRECT_INVAL;
1896 }
1897 }
1898
1899 /*
1900 * This is called to remove the second-level cached zone-2 offset from
1901 * frontend buffer cache buffers, now stale due to a data relocation.
1902 * These offsets are generated by cluster_read() via VOP_BMAP, or directly
1903 * by hammer_vop_strategy_read().
1904 *
1905 * This is rather nasty because here we have something like the reblocker
1906 * scanning the raw B-Tree with no held references on anything, really,
1907 * other then a shared lock on the B-Tree node, and we have to access the
1908 * frontend's buffer cache to check for and clean out the association.
1909 * Specifically, if the reblocker is moving data on the disk, these cached
1910 * offsets will become invalid.
1911 *
1912 * Only data record types associated with the large-data zone are subject
1913 * to direct-io and need to be checked.
1914 *
1915 */
1916 void
hammer_io_direct_uncache(hammer_mount_t hmp,hammer_btree_leaf_elm_t leaf)1917 hammer_io_direct_uncache(hammer_mount_t hmp, hammer_btree_leaf_elm_t leaf)
1918 {
1919 struct hammer_inode_info iinfo;
1920 int zone;
1921
1922 if (leaf->base.rec_type != HAMMER_RECTYPE_DATA)
1923 return;
1924 zone = HAMMER_ZONE_DECODE(leaf->data_offset);
1925 if (zone != HAMMER_ZONE_LARGE_DATA_INDEX)
1926 return;
1927 iinfo.obj_id = leaf->base.obj_id;
1928 iinfo.obj_asof = 0; /* unused */
1929 iinfo.obj_localization = leaf->base.localization &
1930 HAMMER_LOCALIZE_PSEUDOFS_MASK;
1931 iinfo.u.leaf = leaf;
1932 hammer_scan_inode_snapshots(hmp, &iinfo,
1933 hammer_io_direct_uncache_callback,
1934 leaf);
1935 }
1936
1937 static int
hammer_io_direct_uncache_callback(hammer_inode_t ip,void * data)1938 hammer_io_direct_uncache_callback(hammer_inode_t ip, void *data)
1939 {
1940 hammer_inode_info_t iinfo = data;
1941 hammer_off_t file_offset;
1942 struct vnode *vp;
1943 struct buf *bp;
1944 int blksize;
1945
1946 if (ip->vp == NULL)
1947 return(0);
1948 file_offset = iinfo->u.leaf->base.key - iinfo->u.leaf->data_len;
1949 blksize = iinfo->u.leaf->data_len;
1950 KKASSERT((blksize & HAMMER_BUFMASK) == 0);
1951
1952 /*
1953 * Warning: FINDBLK_TEST return stable storage but not stable
1954 * contents. It happens to be ok in this case.
1955 */
1956 hammer_ref(&ip->lock);
1957 if (hammer_get_vnode(ip, &vp) == 0) {
1958 if ((bp = findblk(ip->vp, file_offset, FINDBLK_TEST)) != NULL &&
1959 bp->b_bio2.bio_offset != NOOFFSET) {
1960 bp = getblk(ip->vp, file_offset, blksize, 0, 0);
1961 bp->b_bio2.bio_offset = NOOFFSET;
1962 brelse(bp);
1963 }
1964 vput(vp);
1965 }
1966 hammer_rel_inode(ip, 0);
1967 return(0);
1968 }
1969
1970
1971 /*
1972 * This function is called when writes may have occured on the volume,
1973 * indicating that the device may be holding cached writes.
1974 */
1975 static __inline void
hammer_io_flush_mark(hammer_volume_t volume)1976 hammer_io_flush_mark(hammer_volume_t volume)
1977 {
1978 atomic_set_int(&volume->vol_flags, HAMMER_VOLF_NEEDFLUSH);
1979 }
1980
1981 /*
1982 * This function ensures that the device has flushed any cached writes out.
1983 */
1984 void
hammer_io_flush_sync(hammer_mount_t hmp)1985 hammer_io_flush_sync(hammer_mount_t hmp)
1986 {
1987 hammer_volume_t volume;
1988 struct buf *bp_base = NULL;
1989 struct buf *bp;
1990
1991 RB_FOREACH(volume, hammer_vol_rb_tree, &hmp->rb_vols_root) {
1992 if (volume->vol_flags & HAMMER_VOLF_NEEDFLUSH) {
1993 atomic_clear_int(&volume->vol_flags,
1994 HAMMER_VOLF_NEEDFLUSH);
1995 bp = getpbuf(NULL);
1996 bp->b_bio1.bio_offset = 0;
1997 bp->b_bufsize = 0;
1998 bp->b_bcount = 0;
1999 bp->b_cmd = BUF_CMD_FLUSH;
2000 bp->b_bio1.bio_caller_info1.cluster_head = bp_base;
2001 bp->b_bio1.bio_done = biodone_sync;
2002 bp->b_bio1.bio_flags |= BIO_SYNC;
2003 bp_base = bp;
2004 vn_strategy(volume->devvp, &bp->b_bio1);
2005 }
2006 }
2007 while ((bp = bp_base) != NULL) {
2008 bp_base = bp->b_bio1.bio_caller_info1.cluster_head;
2009 biowait(&bp->b_bio1, "hmrFLS");
2010 relpbuf(bp, NULL);
2011 }
2012 }
2013
2014 /*
2015 * Limit the amount of backlog which we allow to build up
2016 */
2017 void
hammer_io_limit_backlog(hammer_mount_t hmp)2018 hammer_io_limit_backlog(hammer_mount_t hmp)
2019 {
2020 waitrunningbufspace();
2021 }
2022