xref: /dragonfly/sys/vfs/hammer/hammer_ondisk.c (revision 768af85b)
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  * $DragonFly: src/sys/vfs/hammer/hammer_ondisk.c,v 1.76 2008/08/29 20:19:08 dillon Exp $
35  */
36 /*
37  * Manage HAMMER's on-disk structures.  These routines are primarily
38  * responsible for interfacing with the kernel's I/O subsystem and for
39  * managing in-memory structures.
40  */
41 
42 #include "hammer.h"
43 #include <sys/fcntl.h>
44 #include <sys/nlookup.h>
45 #include <sys/buf.h>
46 #include <sys/buf2.h>
47 
48 static void hammer_free_volume(hammer_volume_t volume);
49 static int hammer_load_volume(hammer_volume_t volume);
50 static int hammer_load_buffer(hammer_buffer_t buffer, int isnew);
51 static int hammer_load_node(hammer_transaction_t trans,
52 				hammer_node_t node, int isnew);
53 
54 static int
55 hammer_vol_rb_compare(hammer_volume_t vol1, hammer_volume_t vol2)
56 {
57 	if (vol1->vol_no < vol2->vol_no)
58 		return(-1);
59 	if (vol1->vol_no > vol2->vol_no)
60 		return(1);
61 	return(0);
62 }
63 
64 /*
65  * hammer_buffer structures are indexed via their zoneX_offset, not
66  * their zone2_offset.
67  */
68 static int
69 hammer_buf_rb_compare(hammer_buffer_t buf1, hammer_buffer_t buf2)
70 {
71 	if (buf1->zoneX_offset < buf2->zoneX_offset)
72 		return(-1);
73 	if (buf1->zoneX_offset > buf2->zoneX_offset)
74 		return(1);
75 	return(0);
76 }
77 
78 static int
79 hammer_nod_rb_compare(hammer_node_t node1, hammer_node_t node2)
80 {
81 	if (node1->node_offset < node2->node_offset)
82 		return(-1);
83 	if (node1->node_offset > node2->node_offset)
84 		return(1);
85 	return(0);
86 }
87 
88 RB_GENERATE2(hammer_vol_rb_tree, hammer_volume, rb_node,
89 	     hammer_vol_rb_compare, int32_t, vol_no);
90 RB_GENERATE2(hammer_buf_rb_tree, hammer_buffer, rb_node,
91 	     hammer_buf_rb_compare, hammer_off_t, zoneX_offset);
92 RB_GENERATE2(hammer_nod_rb_tree, hammer_node, rb_node,
93 	     hammer_nod_rb_compare, hammer_off_t, node_offset);
94 
95 /************************************************************************
96  *				VOLUMES					*
97  ************************************************************************
98  *
99  * Load a HAMMER volume by name.  Returns 0 on success or a positive error
100  * code on failure.  Volumes must be loaded at mount time, get_volume() will
101  * not load a new volume.
102  *
103  * Calls made to hammer_load_volume() or single-threaded
104  */
105 int
106 hammer_install_volume(struct hammer_mount *hmp, const char *volname,
107 		      struct vnode *devvp)
108 {
109 	struct mount *mp;
110 	hammer_volume_t volume;
111 	struct hammer_volume_ondisk *ondisk;
112 	struct nlookupdata nd;
113 	struct buf *bp = NULL;
114 	int error;
115 	int ronly;
116 	int setmp = 0;
117 
118 	mp = hmp->mp;
119 	ronly = ((mp->mnt_flag & MNT_RDONLY) ? 1 : 0);
120 
121 	/*
122 	 * Allocate a volume structure
123 	 */
124 	++hammer_count_volumes;
125 	volume = kmalloc(sizeof(*volume), hmp->m_misc, M_WAITOK|M_ZERO);
126 	volume->vol_name = kstrdup(volname, hmp->m_misc);
127 	volume->io.hmp = hmp;	/* bootstrap */
128 	hammer_io_init(&volume->io, volume, HAMMER_STRUCTURE_VOLUME);
129 	volume->io.offset = 0LL;
130 	volume->io.bytes = HAMMER_BUFSIZE;
131 
132 	/*
133 	 * Get the device vnode
134 	 */
135 	if (devvp == NULL) {
136 		error = nlookup_init(&nd, volume->vol_name, UIO_SYSSPACE, NLC_FOLLOW);
137 		if (error == 0)
138 			error = nlookup(&nd);
139 		if (error == 0)
140 			error = cache_vref(&nd.nl_nch, nd.nl_cred, &volume->devvp);
141 		nlookup_done(&nd);
142 	} else {
143 		error = 0;
144 		volume->devvp = devvp;
145 	}
146 
147 	if (error == 0) {
148 		if (vn_isdisk(volume->devvp, &error)) {
149 			error = vfs_mountedon(volume->devvp);
150 		}
151 	}
152 	if (error == 0 && vcount(volume->devvp) > 0)
153 		error = EBUSY;
154 	if (error == 0) {
155 		vn_lock(volume->devvp, LK_EXCLUSIVE | LK_RETRY);
156 		error = vinvalbuf(volume->devvp, V_SAVE, 0, 0);
157 		if (error == 0) {
158 			error = VOP_OPEN(volume->devvp,
159 					 (ronly ? FREAD : FREAD|FWRITE),
160 					 FSCRED, NULL);
161 		}
162 		vn_unlock(volume->devvp);
163 	}
164 	if (error) {
165 		hammer_free_volume(volume);
166 		return(error);
167 	}
168 	volume->devvp->v_rdev->si_mountpoint = mp;
169 	setmp = 1;
170 
171 	/*
172 	 * Extract the volume number from the volume header and do various
173 	 * sanity checks.
174 	 */
175 	error = bread(volume->devvp, 0LL, HAMMER_BUFSIZE, &bp);
176 	if (error)
177 		goto late_failure;
178 	ondisk = (void *)bp->b_data;
179 	if (ondisk->vol_signature != HAMMER_FSBUF_VOLUME) {
180 		kprintf("hammer_mount: volume %s has an invalid header\n",
181 			volume->vol_name);
182 		error = EFTYPE;
183 		goto late_failure;
184 	}
185 	volume->vol_no = ondisk->vol_no;
186 	volume->buffer_base = ondisk->vol_buf_beg;
187 	volume->vol_flags = ondisk->vol_flags;
188 	volume->nblocks = ondisk->vol_nblocks;
189 	volume->maxbuf_off = HAMMER_ENCODE_RAW_BUFFER(volume->vol_no,
190 				    ondisk->vol_buf_end - ondisk->vol_buf_beg);
191 	volume->maxraw_off = ondisk->vol_buf_end;
192 
193 	if (RB_EMPTY(&hmp->rb_vols_root)) {
194 		hmp->fsid = ondisk->vol_fsid;
195 	} else if (bcmp(&hmp->fsid, &ondisk->vol_fsid, sizeof(uuid_t))) {
196 		kprintf("hammer_mount: volume %s's fsid does not match "
197 			"other volumes\n", volume->vol_name);
198 		error = EFTYPE;
199 		goto late_failure;
200 	}
201 
202 	/*
203 	 * Insert the volume structure into the red-black tree.
204 	 */
205 	if (RB_INSERT(hammer_vol_rb_tree, &hmp->rb_vols_root, volume)) {
206 		kprintf("hammer_mount: volume %s has a duplicate vol_no %d\n",
207 			volume->vol_name, volume->vol_no);
208 		error = EEXIST;
209 	}
210 
211 	/*
212 	 * Set the root volume .  HAMMER special cases rootvol the structure.
213 	 * We do not hold a ref because this would prevent related I/O
214 	 * from being flushed.
215 	 */
216 	if (error == 0 && ondisk->vol_rootvol == ondisk->vol_no) {
217 		hmp->rootvol = volume;
218 		hmp->nvolumes = ondisk->vol_count;
219 		if (bp) {
220 			brelse(bp);
221 			bp = NULL;
222 		}
223 		hmp->mp->mnt_stat.f_blocks += ondisk->vol0_stat_bigblocks *
224 			(HAMMER_LARGEBLOCK_SIZE / HAMMER_BUFSIZE);
225 		hmp->mp->mnt_vstat.f_blocks += ondisk->vol0_stat_bigblocks *
226 			(HAMMER_LARGEBLOCK_SIZE / HAMMER_BUFSIZE);
227 	}
228 late_failure:
229 	if (bp)
230 		brelse(bp);
231 	if (error) {
232 		/*vinvalbuf(volume->devvp, V_SAVE, 0, 0);*/
233 		if (setmp)
234 			volume->devvp->v_rdev->si_mountpoint = NULL;
235 		VOP_CLOSE(volume->devvp, ronly ? FREAD : FREAD|FWRITE);
236 		hammer_free_volume(volume);
237 	}
238 	return (error);
239 }
240 
241 /*
242  * This is called for each volume when updating the mount point from
243  * read-write to read-only or vise-versa.
244  */
245 int
246 hammer_adjust_volume_mode(hammer_volume_t volume, void *data __unused)
247 {
248 	if (volume->devvp) {
249 		vn_lock(volume->devvp, LK_EXCLUSIVE | LK_RETRY);
250 		if (volume->io.hmp->ronly) {
251 			/* do not call vinvalbuf */
252 			VOP_OPEN(volume->devvp, FREAD, FSCRED, NULL);
253 			VOP_CLOSE(volume->devvp, FREAD|FWRITE);
254 		} else {
255 			/* do not call vinvalbuf */
256 			VOP_OPEN(volume->devvp, FREAD|FWRITE, FSCRED, NULL);
257 			VOP_CLOSE(volume->devvp, FREAD);
258 		}
259 		vn_unlock(volume->devvp);
260 	}
261 	return(0);
262 }
263 
264 /*
265  * Unload and free a HAMMER volume.  Must return >= 0 to continue scan
266  * so returns -1 on failure.
267  */
268 int
269 hammer_unload_volume(hammer_volume_t volume, void *data __unused)
270 {
271 	hammer_mount_t hmp = volume->io.hmp;
272 	int ronly = ((hmp->mp->mnt_flag & MNT_RDONLY) ? 1 : 0);
273 
274 	/*
275 	 * Clean up the root volume pointer, which is held unlocked in hmp.
276 	 */
277 	if (hmp->rootvol == volume)
278 		hmp->rootvol = NULL;
279 
280 	/*
281 	 * We must not flush a dirty buffer to disk on umount.  It should
282 	 * have already been dealt with by the flusher, or we may be in
283 	 * catastrophic failure.
284 	 */
285 	hammer_io_clear_modify(&volume->io, 1);
286 	volume->io.waitdep = 1;
287 
288 	/*
289 	 * Clean up the persistent ref ioerror might have on the volume
290 	 */
291 	if (volume->io.ioerror) {
292 		volume->io.ioerror = 0;
293 		hammer_unref(&volume->io.lock);
294 	}
295 
296 	/*
297 	 * This should release the bp.
298 	 */
299 	KKASSERT(volume->io.lock.refs == 0);
300 	hammer_ref(&volume->io.lock);
301 	hammer_rel_volume(volume, 1);
302 	KKASSERT(volume->io.bp == NULL);
303 
304 	/*
305 	 * There should be no references on the volume, no clusters, and
306 	 * no super-clusters.
307 	 */
308 	KKASSERT(volume->io.lock.refs == 0);
309 
310 	volume->ondisk = NULL;
311 	if (volume->devvp) {
312 		if (volume->devvp->v_rdev &&
313 		    volume->devvp->v_rdev->si_mountpoint == hmp->mp
314 		) {
315 			volume->devvp->v_rdev->si_mountpoint = NULL;
316 		}
317 		if (ronly) {
318 			/*
319 			 * Make sure we don't sync anything to disk if we
320 			 * are in read-only mode (1) or critically-errored
321 			 * (2).  Note that there may be dirty buffers in
322 			 * normal read-only mode from crash recovery.
323 			 */
324 			vinvalbuf(volume->devvp, 0, 0, 0);
325 			VOP_CLOSE(volume->devvp, FREAD);
326 		} else {
327 			/*
328 			 * Normal termination, save any dirty buffers
329 			 * (XXX there really shouldn't be any).
330 			 */
331 			vinvalbuf(volume->devvp, V_SAVE, 0, 0);
332 			VOP_CLOSE(volume->devvp, FREAD|FWRITE);
333 		}
334 	}
335 
336 	/*
337 	 * Destroy the structure
338 	 */
339 	RB_REMOVE(hammer_vol_rb_tree, &hmp->rb_vols_root, volume);
340 	hammer_free_volume(volume);
341 	return(0);
342 }
343 
344 static
345 void
346 hammer_free_volume(hammer_volume_t volume)
347 {
348 	hammer_mount_t hmp = volume->io.hmp;
349 
350 	if (volume->vol_name) {
351 		kfree(volume->vol_name, hmp->m_misc);
352 		volume->vol_name = NULL;
353 	}
354 	if (volume->devvp) {
355 		vrele(volume->devvp);
356 		volume->devvp = NULL;
357 	}
358 	--hammer_count_volumes;
359 	kfree(volume, hmp->m_misc);
360 }
361 
362 /*
363  * Get a HAMMER volume.  The volume must already exist.
364  */
365 hammer_volume_t
366 hammer_get_volume(struct hammer_mount *hmp, int32_t vol_no, int *errorp)
367 {
368 	struct hammer_volume *volume;
369 
370 	/*
371 	 * Locate the volume structure
372 	 */
373 	volume = RB_LOOKUP(hammer_vol_rb_tree, &hmp->rb_vols_root, vol_no);
374 	if (volume == NULL) {
375 		*errorp = ENOENT;
376 		return(NULL);
377 	}
378 	hammer_ref(&volume->io.lock);
379 
380 	/*
381 	 * Deal with on-disk info
382 	 */
383 	if (volume->ondisk == NULL || volume->io.loading) {
384 		*errorp = hammer_load_volume(volume);
385 		if (*errorp) {
386 			hammer_rel_volume(volume, 1);
387 			volume = NULL;
388 		}
389 	} else {
390 		*errorp = 0;
391 	}
392 	return(volume);
393 }
394 
395 int
396 hammer_ref_volume(hammer_volume_t volume)
397 {
398 	int error;
399 
400 	hammer_ref(&volume->io.lock);
401 
402 	/*
403 	 * Deal with on-disk info
404 	 */
405 	if (volume->ondisk == NULL || volume->io.loading) {
406 		error = hammer_load_volume(volume);
407 		if (error)
408 			hammer_rel_volume(volume, 1);
409 	} else {
410 		error = 0;
411 	}
412 	return (error);
413 }
414 
415 hammer_volume_t
416 hammer_get_root_volume(struct hammer_mount *hmp, int *errorp)
417 {
418 	hammer_volume_t volume;
419 
420 	volume = hmp->rootvol;
421 	KKASSERT(volume != NULL);
422 	hammer_ref(&volume->io.lock);
423 
424 	/*
425 	 * Deal with on-disk info
426 	 */
427 	if (volume->ondisk == NULL || volume->io.loading) {
428 		*errorp = hammer_load_volume(volume);
429 		if (*errorp) {
430 			hammer_rel_volume(volume, 1);
431 			volume = NULL;
432 		}
433 	} else {
434 		*errorp = 0;
435 	}
436 	return (volume);
437 }
438 
439 /*
440  * Load a volume's on-disk information.  The volume must be referenced and
441  * not locked.  We temporarily acquire an exclusive lock to interlock
442  * against releases or multiple get's.
443  */
444 static int
445 hammer_load_volume(hammer_volume_t volume)
446 {
447 	int error;
448 
449 	++volume->io.loading;
450 	hammer_lock_ex(&volume->io.lock);
451 
452 	if (volume->ondisk == NULL) {
453 		error = hammer_io_read(volume->devvp, &volume->io,
454 				       volume->maxraw_off);
455 		if (error == 0)
456 			volume->ondisk = (void *)volume->io.bp->b_data;
457 	} else {
458 		error = 0;
459 	}
460 	--volume->io.loading;
461 	hammer_unlock(&volume->io.lock);
462 	return(error);
463 }
464 
465 /*
466  * Release a volume.  Call hammer_io_release on the last reference.  We have
467  * to acquire an exclusive lock to interlock against volume->ondisk tests
468  * in hammer_load_volume(), and hammer_io_release() also expects an exclusive
469  * lock to be held.
470  *
471  * Volumes are not unloaded from memory during normal operation.
472  */
473 void
474 hammer_rel_volume(hammer_volume_t volume, int flush)
475 {
476 	struct buf *bp = NULL;
477 
478 	crit_enter();
479 	if (volume->io.lock.refs == 1) {
480 		++volume->io.loading;
481 		hammer_lock_ex(&volume->io.lock);
482 		if (volume->io.lock.refs == 1) {
483 			volume->ondisk = NULL;
484 			bp = hammer_io_release(&volume->io, flush);
485 		}
486 		--volume->io.loading;
487 		hammer_unlock(&volume->io.lock);
488 	}
489 	hammer_unref(&volume->io.lock);
490 	if (bp)
491 		brelse(bp);
492 	crit_exit();
493 }
494 
495 int
496 hammer_mountcheck_volumes(struct hammer_mount *hmp)
497 {
498 	hammer_volume_t vol;
499 	int i;
500 
501 	for (i = 0; i < hmp->nvolumes; ++i) {
502 		vol = RB_LOOKUP(hammer_vol_rb_tree, &hmp->rb_vols_root, i);
503 		if (vol == NULL)
504 			return(EINVAL);
505 	}
506 	return(0);
507 }
508 
509 /************************************************************************
510  *				BUFFERS					*
511  ************************************************************************
512  *
513  * Manage buffers.  Currently most blockmap-backed zones are direct-mapped
514  * to zone-2 buffer offsets, without a translation stage.  However, the
515  * hammer_buffer structure is indexed by its zoneX_offset, not its
516  * zone2_offset.
517  *
518  * The proper zone must be maintained throughout the code-base all the way
519  * through to the big-block allocator, or routines like hammer_del_buffers()
520  * will not be able to locate all potentially conflicting buffers.
521  */
522 hammer_buffer_t
523 hammer_get_buffer(hammer_mount_t hmp, hammer_off_t buf_offset,
524 		  int bytes, int isnew, int *errorp)
525 {
526 	hammer_buffer_t buffer;
527 	hammer_volume_t volume;
528 	hammer_off_t	zone2_offset;
529 	hammer_io_type_t iotype;
530 	int vol_no;
531 	int zone;
532 
533 	buf_offset &= ~HAMMER_BUFMASK64;
534 again:
535 	/*
536 	 * Shortcut if the buffer is already cached
537 	 */
538 	buffer = RB_LOOKUP(hammer_buf_rb_tree, &hmp->rb_bufs_root, buf_offset);
539 	if (buffer) {
540 		if (buffer->io.lock.refs == 0)
541 			++hammer_count_refedbufs;
542 		hammer_ref(&buffer->io.lock);
543 
544 		/*
545 		 * Once refed the ondisk field will not be cleared by
546 		 * any other action.
547 		 */
548 		if (buffer->ondisk && buffer->io.loading == 0) {
549 			*errorp = 0;
550 			hammer_io_advance(&buffer->io);
551 			return(buffer);
552 		}
553 
554 		/*
555 		 * The buffer is no longer loose if it has a ref, and
556 		 * cannot become loose once it gains a ref.  Loose
557 		 * buffers will never be in a modified state.  This should
558 		 * only occur on the 0->1 transition of refs.
559 		 *
560 		 * lose_list can be modified via a biodone() interrupt.
561 		 */
562 		if (buffer->io.mod_list == &hmp->lose_list) {
563 			crit_enter();	/* biodone race against list */
564 			TAILQ_REMOVE(buffer->io.mod_list, &buffer->io,
565 				     mod_entry);
566 			crit_exit();
567 			buffer->io.mod_list = NULL;
568 			KKASSERT(buffer->io.modified == 0);
569 		}
570 		goto found;
571 	}
572 
573 	/*
574 	 * What is the buffer class?
575 	 */
576 	zone = HAMMER_ZONE_DECODE(buf_offset);
577 
578 	switch(zone) {
579 	case HAMMER_ZONE_LARGE_DATA_INDEX:
580 	case HAMMER_ZONE_SMALL_DATA_INDEX:
581 		iotype = HAMMER_STRUCTURE_DATA_BUFFER;
582 		break;
583 	case HAMMER_ZONE_UNDO_INDEX:
584 		iotype = HAMMER_STRUCTURE_UNDO_BUFFER;
585 		break;
586 	case HAMMER_ZONE_META_INDEX:
587 	default:
588 		/*
589 		 * NOTE: inode data and directory entries are placed in this
590 		 * zone.  inode atime/mtime is updated in-place and thus
591 		 * buffers containing inodes must be synchronized as
592 		 * meta-buffers, same as buffers containing B-Tree info.
593 		 */
594 		iotype = HAMMER_STRUCTURE_META_BUFFER;
595 		break;
596 	}
597 
598 	/*
599 	 * Handle blockmap offset translations
600 	 */
601 	if (zone >= HAMMER_ZONE_BTREE_INDEX) {
602 		zone2_offset = hammer_blockmap_lookup(hmp, buf_offset, errorp);
603 	} else if (zone == HAMMER_ZONE_UNDO_INDEX) {
604 		zone2_offset = hammer_undo_lookup(hmp, buf_offset, errorp);
605 	} else {
606 		KKASSERT(zone == HAMMER_ZONE_RAW_BUFFER_INDEX);
607 		zone2_offset = buf_offset;
608 		*errorp = 0;
609 	}
610 	if (*errorp)
611 		return(NULL);
612 
613 	/*
614 	 * NOTE: zone2_offset and maxbuf_off are both full zone-2 offset
615 	 * specifications.
616 	 */
617 	KKASSERT((zone2_offset & HAMMER_OFF_ZONE_MASK) ==
618 		 HAMMER_ZONE_RAW_BUFFER);
619 	vol_no = HAMMER_VOL_DECODE(zone2_offset);
620 	volume = hammer_get_volume(hmp, vol_no, errorp);
621 	if (volume == NULL)
622 		return(NULL);
623 
624 	KKASSERT(zone2_offset < volume->maxbuf_off);
625 
626 	/*
627 	 * Allocate a new buffer structure.  We will check for races later.
628 	 */
629 	++hammer_count_buffers;
630 	buffer = kmalloc(sizeof(*buffer), hmp->m_misc,
631 			 M_WAITOK|M_ZERO|M_USE_RESERVE);
632 	buffer->zone2_offset = zone2_offset;
633 	buffer->zoneX_offset = buf_offset;
634 
635 	hammer_io_init(&buffer->io, volume, iotype);
636 	buffer->io.offset = volume->ondisk->vol_buf_beg +
637 			    (zone2_offset & HAMMER_OFF_SHORT_MASK);
638 	buffer->io.bytes = bytes;
639 	TAILQ_INIT(&buffer->clist);
640 	hammer_ref(&buffer->io.lock);
641 
642 	/*
643 	 * Insert the buffer into the RB tree and handle late collisions.
644 	 */
645 	if (RB_INSERT(hammer_buf_rb_tree, &hmp->rb_bufs_root, buffer)) {
646 		hammer_rel_volume(volume, 0);
647 		buffer->io.volume = NULL;	/* safety */
648 		hammer_unref(&buffer->io.lock);	/* safety */
649 		--hammer_count_buffers;
650 		kfree(buffer, hmp->m_misc);
651 		goto again;
652 	}
653 	++hammer_count_refedbufs;
654 found:
655 
656 	/*
657 	 * Deal with on-disk info and loading races.
658 	 */
659 	if (buffer->ondisk == NULL || buffer->io.loading) {
660 		*errorp = hammer_load_buffer(buffer, isnew);
661 		if (*errorp) {
662 			hammer_rel_buffer(buffer, 1);
663 			buffer = NULL;
664 		} else {
665 			hammer_io_advance(&buffer->io);
666 		}
667 	} else {
668 		*errorp = 0;
669 		hammer_io_advance(&buffer->io);
670 	}
671 	return(buffer);
672 }
673 
674 /*
675  * This is used by the direct-read code to deal with large-data buffers
676  * created by the reblocker and mirror-write code.  The direct-read code
677  * bypasses the HAMMER buffer subsystem and so any aliased dirty or write-
678  * running hammer buffers must be fully synced to disk before we can issue
679  * the direct-read.
680  *
681  * This code path is not considered critical as only the rebocker and
682  * mirror-write code will create large-data buffers via the HAMMER buffer
683  * subsystem.  They do that because they operate at the B-Tree level and
684  * do not access the vnode/inode structures.
685  */
686 void
687 hammer_sync_buffers(hammer_mount_t hmp, hammer_off_t base_offset, int bytes)
688 {
689 	hammer_buffer_t buffer;
690 	int error;
691 
692 	KKASSERT((base_offset & HAMMER_OFF_ZONE_MASK) ==
693 		 HAMMER_ZONE_LARGE_DATA);
694 
695 	while (bytes > 0) {
696 		buffer = RB_LOOKUP(hammer_buf_rb_tree, &hmp->rb_bufs_root,
697 				   base_offset);
698 		if (buffer && (buffer->io.modified || buffer->io.running)) {
699 			error = hammer_ref_buffer(buffer);
700 			if (error == 0) {
701 				hammer_io_wait(&buffer->io);
702 				if (buffer->io.modified) {
703 					hammer_io_write_interlock(&buffer->io);
704 					hammer_io_flush(&buffer->io, 0);
705 					hammer_io_done_interlock(&buffer->io);
706 					hammer_io_wait(&buffer->io);
707 				}
708 				hammer_rel_buffer(buffer, 0);
709 			}
710 		}
711 		base_offset += HAMMER_BUFSIZE;
712 		bytes -= HAMMER_BUFSIZE;
713 	}
714 }
715 
716 /*
717  * Destroy all buffers covering the specified zoneX offset range.  This
718  * is called when the related blockmap layer2 entry is freed or when
719  * a direct write bypasses our buffer/buffer-cache subsystem.
720  *
721  * The buffers may be referenced by the caller itself.  Setting reclaim
722  * will cause the buffer to be destroyed when it's ref count reaches zero.
723  *
724  * Return 0 on success, EAGAIN if some buffers could not be destroyed due
725  * to additional references held by other threads, or some other (typically
726  * fatal) error.
727  */
728 int
729 hammer_del_buffers(hammer_mount_t hmp, hammer_off_t base_offset,
730 		   hammer_off_t zone2_offset, int bytes,
731 		   int report_conflicts)
732 {
733 	hammer_buffer_t buffer;
734 	hammer_volume_t volume;
735 	int vol_no;
736 	int error;
737 	int ret_error;
738 
739 	vol_no = HAMMER_VOL_DECODE(zone2_offset);
740 	volume = hammer_get_volume(hmp, vol_no, &ret_error);
741 	KKASSERT(ret_error == 0);
742 
743 	while (bytes > 0) {
744 		buffer = RB_LOOKUP(hammer_buf_rb_tree, &hmp->rb_bufs_root,
745 				   base_offset);
746 		if (buffer) {
747 			error = hammer_ref_buffer(buffer);
748 			if (error == 0 && buffer->io.lock.refs != 1) {
749 				error = EAGAIN;
750 				hammer_rel_buffer(buffer, 0);
751 			}
752 			if (error == 0) {
753 				KKASSERT(buffer->zone2_offset == zone2_offset);
754 				hammer_io_clear_modify(&buffer->io, 1);
755 				buffer->io.reclaim = 1;
756 				buffer->io.waitdep = 1;
757 				KKASSERT(buffer->io.volume == volume);
758 				hammer_rel_buffer(buffer, 0);
759 			}
760 		} else {
761 			error = hammer_io_inval(volume, zone2_offset);
762 		}
763 		if (error) {
764 			ret_error = error;
765 			if (report_conflicts ||
766 			    (hammer_debug_general & 0x8000)) {
767 				kprintf("hammer_del_buffers: unable to "
768 					"invalidate %016llx buffer=%p rep=%d\n",
769 					(long long)base_offset,
770 					buffer, report_conflicts);
771 			}
772 		}
773 		base_offset += HAMMER_BUFSIZE;
774 		zone2_offset += HAMMER_BUFSIZE;
775 		bytes -= HAMMER_BUFSIZE;
776 	}
777 	hammer_rel_volume(volume, 0);
778 	return (ret_error);
779 }
780 
781 static int
782 hammer_load_buffer(hammer_buffer_t buffer, int isnew)
783 {
784 	hammer_volume_t volume;
785 	int error;
786 
787 	/*
788 	 * Load the buffer's on-disk info
789 	 */
790 	volume = buffer->io.volume;
791 	++buffer->io.loading;
792 	hammer_lock_ex(&buffer->io.lock);
793 
794 	if (hammer_debug_io & 0x0001) {
795 		kprintf("load_buffer %016llx %016llx isnew=%d od=%p\n",
796 			(long long)buffer->zoneX_offset,
797 			(long long)buffer->zone2_offset,
798 			isnew, buffer->ondisk);
799 	}
800 
801 	if (buffer->ondisk == NULL) {
802 		if (isnew) {
803 			error = hammer_io_new(volume->devvp, &buffer->io);
804 		} else {
805 			error = hammer_io_read(volume->devvp, &buffer->io,
806 					       volume->maxraw_off);
807 		}
808 		if (error == 0)
809 			buffer->ondisk = (void *)buffer->io.bp->b_data;
810 	} else if (isnew) {
811 		error = hammer_io_new(volume->devvp, &buffer->io);
812 	} else {
813 		error = 0;
814 	}
815 	--buffer->io.loading;
816 	hammer_unlock(&buffer->io.lock);
817 	return (error);
818 }
819 
820 /*
821  * NOTE: Called from RB_SCAN, must return >= 0 for scan to continue.
822  * This routine is only called during unmount or when a volume is
823  * removed.
824  *
825  * If data != NULL, it specifies a volume whoose buffers should
826  * be unloaded.
827  */
828 int
829 hammer_unload_buffer(hammer_buffer_t buffer, void *data)
830 {
831 	struct hammer_volume *volume = (struct hammer_volume *) data;
832 
833 	if (volume != NULL && volume != buffer->io.volume) {
834 		/*
835 		 * We are only interested in unloading buffers of volume,
836 		 * so skip it
837 		 */
838 		return 0;
839 	}
840 
841 	/*
842 	 * Clean up the persistent ref ioerror might have on the buffer
843 	 * and acquire a ref (steal ioerror's if we can).
844 	 */
845 	if (buffer->io.ioerror) {
846 		buffer->io.ioerror = 0;
847 	} else {
848 		if (buffer->io.lock.refs == 0)
849 			++hammer_count_refedbufs;
850 		hammer_ref(&buffer->io.lock);
851 	}
852 
853 	/*
854 	 * We must not flush a dirty buffer to disk on umount.  It should
855 	 * have already been dealt with by the flusher, or we may be in
856 	 * catastrophic failure.
857 	 *
858 	 * We must set waitdep to ensure that a running buffer is waited
859 	 * on and released prior to us trying to unload the volume.
860 	 */
861 	hammer_io_clear_modify(&buffer->io, 1);
862 	hammer_flush_buffer_nodes(buffer);
863 	KKASSERT(buffer->io.lock.refs == 1);
864 	buffer->io.waitdep = 1;
865 	hammer_rel_buffer(buffer, 2);
866 	return(0);
867 }
868 
869 /*
870  * Reference a buffer that is either already referenced or via a specially
871  * handled pointer (aka cursor->buffer).
872  */
873 int
874 hammer_ref_buffer(hammer_buffer_t buffer)
875 {
876 	int error;
877 
878 	if (buffer->io.lock.refs == 0)
879 		++hammer_count_refedbufs;
880 	hammer_ref(&buffer->io.lock);
881 
882 	/*
883 	 * At this point a biodone() will not touch the buffer other then
884 	 * incidental bits.  However, lose_list can be modified via
885 	 * a biodone() interrupt.
886 	 *
887 	 * No longer loose
888 	 */
889 	if (buffer->io.mod_list == &buffer->io.hmp->lose_list) {
890 		crit_enter();
891 		TAILQ_REMOVE(buffer->io.mod_list, &buffer->io, mod_entry);
892 		buffer->io.mod_list = NULL;
893 		crit_exit();
894 	}
895 
896 	if (buffer->ondisk == NULL || buffer->io.loading) {
897 		error = hammer_load_buffer(buffer, 0);
898 		if (error) {
899 			hammer_rel_buffer(buffer, 1);
900 			/*
901 			 * NOTE: buffer pointer can become stale after
902 			 * the above release.
903 			 */
904 		}
905 	} else {
906 		error = 0;
907 	}
908 	return(error);
909 }
910 
911 /*
912  * Release a buffer.  We have to deal with several places where
913  * another thread can ref the buffer.
914  *
915  * Only destroy the structure itself if the related buffer cache buffer
916  * was disassociated from it.  This ties the management of the structure
917  * to the buffer cache subsystem.  buffer->ondisk determines whether the
918  * embedded io is referenced or not.
919  */
920 void
921 hammer_rel_buffer(hammer_buffer_t buffer, int flush)
922 {
923 	hammer_volume_t volume;
924 	hammer_mount_t hmp;
925 	struct buf *bp = NULL;
926 	int freeme = 0;
927 
928 	hmp = buffer->io.hmp;
929 
930 	crit_enter();
931 	if (buffer->io.lock.refs == 1) {
932 		++buffer->io.loading;	/* force interlock check */
933 		hammer_lock_ex(&buffer->io.lock);
934 		if (buffer->io.lock.refs == 1) {
935 			bp = hammer_io_release(&buffer->io, flush);
936 
937 			if (buffer->io.lock.refs == 1)
938 				--hammer_count_refedbufs;
939 
940 			if (buffer->io.bp == NULL &&
941 			    buffer->io.lock.refs == 1) {
942 				/*
943 				 * Final cleanup
944 				 *
945 				 * NOTE: It is impossible for any associated
946 				 * B-Tree nodes to have refs if the buffer
947 				 * has no additional refs.
948 				 */
949 				RB_REMOVE(hammer_buf_rb_tree,
950 					  &buffer->io.hmp->rb_bufs_root,
951 					  buffer);
952 				volume = buffer->io.volume;
953 				buffer->io.volume = NULL; /* sanity */
954 				hammer_rel_volume(volume, 0);
955 				hammer_io_clear_modlist(&buffer->io);
956 				hammer_flush_buffer_nodes(buffer);
957 				KKASSERT(TAILQ_EMPTY(&buffer->clist));
958 				freeme = 1;
959 			}
960 		}
961 		--buffer->io.loading;
962 		hammer_unlock(&buffer->io.lock);
963 	}
964 	hammer_unref(&buffer->io.lock);
965 	crit_exit();
966 	if (bp)
967 		brelse(bp);
968 	if (freeme) {
969 		--hammer_count_buffers;
970 		kfree(buffer, hmp->m_misc);
971 	}
972 }
973 
974 /*
975  * Access the filesystem buffer containing the specified hammer offset.
976  * buf_offset is a conglomeration of the volume number and vol_buf_beg
977  * relative buffer offset.  It must also have bit 55 set to be valid.
978  * (see hammer_off_t in hammer_disk.h).
979  *
980  * Any prior buffer in *bufferp will be released and replaced by the
981  * requested buffer.
982  *
983  * NOTE: The buffer is indexed via its zoneX_offset but we allow the
984  * passed cached *bufferp to match against either zoneX or zone2.
985  */
986 static __inline
987 void *
988 _hammer_bread(hammer_mount_t hmp, hammer_off_t buf_offset, int bytes,
989 	     int *errorp, struct hammer_buffer **bufferp)
990 {
991 	hammer_buffer_t buffer;
992 	int32_t xoff = (int32_t)buf_offset & HAMMER_BUFMASK;
993 
994 	buf_offset &= ~HAMMER_BUFMASK64;
995 	KKASSERT((buf_offset & HAMMER_OFF_ZONE_MASK) != 0);
996 
997 	buffer = *bufferp;
998 	if (buffer == NULL || (buffer->zone2_offset != buf_offset &&
999 			       buffer->zoneX_offset != buf_offset)) {
1000 		if (buffer)
1001 			hammer_rel_buffer(buffer, 0);
1002 		buffer = hammer_get_buffer(hmp, buf_offset, bytes, 0, errorp);
1003 		*bufferp = buffer;
1004 	} else {
1005 		*errorp = 0;
1006 	}
1007 
1008 	/*
1009 	 * Return a pointer to the buffer data.
1010 	 */
1011 	if (buffer == NULL)
1012 		return(NULL);
1013 	else
1014 		return((char *)buffer->ondisk + xoff);
1015 }
1016 
1017 void *
1018 hammer_bread(hammer_mount_t hmp, hammer_off_t buf_offset,
1019 	     int *errorp, struct hammer_buffer **bufferp)
1020 {
1021 	return(_hammer_bread(hmp, buf_offset, HAMMER_BUFSIZE, errorp, bufferp));
1022 }
1023 
1024 void *
1025 hammer_bread_ext(hammer_mount_t hmp, hammer_off_t buf_offset, int bytes,
1026 	         int *errorp, struct hammer_buffer **bufferp)
1027 {
1028 	bytes = (bytes + HAMMER_BUFMASK) & ~HAMMER_BUFMASK;
1029 	return(_hammer_bread(hmp, buf_offset, bytes, errorp, bufferp));
1030 }
1031 
1032 /*
1033  * Access the filesystem buffer containing the specified hammer offset.
1034  * No disk read operation occurs.  The result buffer may contain garbage.
1035  *
1036  * Any prior buffer in *bufferp will be released and replaced by the
1037  * requested buffer.
1038  *
1039  * This function marks the buffer dirty but does not increment its
1040  * modify_refs count.
1041  */
1042 static __inline
1043 void *
1044 _hammer_bnew(hammer_mount_t hmp, hammer_off_t buf_offset, int bytes,
1045 	     int *errorp, struct hammer_buffer **bufferp)
1046 {
1047 	hammer_buffer_t buffer;
1048 	int32_t xoff = (int32_t)buf_offset & HAMMER_BUFMASK;
1049 
1050 	buf_offset &= ~HAMMER_BUFMASK64;
1051 
1052 	buffer = *bufferp;
1053 	if (buffer == NULL || (buffer->zone2_offset != buf_offset &&
1054 			       buffer->zoneX_offset != buf_offset)) {
1055 		if (buffer)
1056 			hammer_rel_buffer(buffer, 0);
1057 		buffer = hammer_get_buffer(hmp, buf_offset, bytes, 1, errorp);
1058 		*bufferp = buffer;
1059 	} else {
1060 		*errorp = 0;
1061 	}
1062 
1063 	/*
1064 	 * Return a pointer to the buffer data.
1065 	 */
1066 	if (buffer == NULL)
1067 		return(NULL);
1068 	else
1069 		return((char *)buffer->ondisk + xoff);
1070 }
1071 
1072 void *
1073 hammer_bnew(hammer_mount_t hmp, hammer_off_t buf_offset,
1074 	     int *errorp, struct hammer_buffer **bufferp)
1075 {
1076 	return(_hammer_bnew(hmp, buf_offset, HAMMER_BUFSIZE, errorp, bufferp));
1077 }
1078 
1079 void *
1080 hammer_bnew_ext(hammer_mount_t hmp, hammer_off_t buf_offset, int bytes,
1081 		int *errorp, struct hammer_buffer **bufferp)
1082 {
1083 	bytes = (bytes + HAMMER_BUFMASK) & ~HAMMER_BUFMASK;
1084 	return(_hammer_bnew(hmp, buf_offset, bytes, errorp, bufferp));
1085 }
1086 
1087 /************************************************************************
1088  *				NODES					*
1089  ************************************************************************
1090  *
1091  * Manage B-Tree nodes.  B-Tree nodes represent the primary indexing
1092  * method used by the HAMMER filesystem.
1093  *
1094  * Unlike other HAMMER structures, a hammer_node can be PASSIVELY
1095  * associated with its buffer, and will only referenced the buffer while
1096  * the node itself is referenced.
1097  *
1098  * A hammer_node can also be passively associated with other HAMMER
1099  * structures, such as inodes, while retaining 0 references.  These
1100  * associations can be cleared backwards using a pointer-to-pointer in
1101  * the hammer_node.
1102  *
1103  * This allows the HAMMER implementation to cache hammer_nodes long-term
1104  * and short-cut a great deal of the infrastructure's complexity.  In
1105  * most cases a cached node can be reacquired without having to dip into
1106  * either the buffer or cluster management code.
1107  *
1108  * The caller must pass a referenced cluster on call and will retain
1109  * ownership of the reference on return.  The node will acquire its own
1110  * additional references, if necessary.
1111  */
1112 hammer_node_t
1113 hammer_get_node(hammer_transaction_t trans, hammer_off_t node_offset,
1114 		int isnew, int *errorp)
1115 {
1116 	hammer_mount_t hmp = trans->hmp;
1117 	hammer_node_t node;
1118 
1119 	KKASSERT((node_offset & HAMMER_OFF_ZONE_MASK) == HAMMER_ZONE_BTREE);
1120 
1121 	/*
1122 	 * Locate the structure, allocating one if necessary.
1123 	 */
1124 again:
1125 	node = RB_LOOKUP(hammer_nod_rb_tree, &hmp->rb_nods_root, node_offset);
1126 	if (node == NULL) {
1127 		++hammer_count_nodes;
1128 		node = kmalloc(sizeof(*node), hmp->m_misc, M_WAITOK|M_ZERO|M_USE_RESERVE);
1129 		node->node_offset = node_offset;
1130 		node->hmp = hmp;
1131 		TAILQ_INIT(&node->cursor_list);
1132 		TAILQ_INIT(&node->cache_list);
1133 		if (RB_INSERT(hammer_nod_rb_tree, &hmp->rb_nods_root, node)) {
1134 			--hammer_count_nodes;
1135 			kfree(node, hmp->m_misc);
1136 			goto again;
1137 		}
1138 	}
1139 	hammer_ref(&node->lock);
1140 	if (node->ondisk) {
1141 		*errorp = 0;
1142 		hammer_io_advance(&node->buffer->io);
1143 	} else {
1144 		*errorp = hammer_load_node(trans, node, isnew);
1145 		trans->flags |= HAMMER_TRANSF_DIDIO;
1146 	}
1147 	if (*errorp) {
1148 		hammer_rel_node(node);
1149 		node = NULL;
1150 	}
1151 	return(node);
1152 }
1153 
1154 /*
1155  * Reference an already-referenced node.
1156  */
1157 void
1158 hammer_ref_node(hammer_node_t node)
1159 {
1160 	KKASSERT(node->lock.refs > 0 && node->ondisk != NULL);
1161 	hammer_ref(&node->lock);
1162 }
1163 
1164 /*
1165  * Load a node's on-disk data reference.
1166  */
1167 static int
1168 hammer_load_node(hammer_transaction_t trans, hammer_node_t node, int isnew)
1169 {
1170 	hammer_buffer_t buffer;
1171 	hammer_off_t buf_offset;
1172 	int error;
1173 
1174 	error = 0;
1175 	++node->loading;
1176 	hammer_lock_ex(&node->lock);
1177 	if (node->ondisk == NULL) {
1178 		/*
1179 		 * This is a little confusing but the jist is that
1180 		 * node->buffer determines whether the node is on
1181 		 * the buffer's clist and node->ondisk determines
1182 		 * whether the buffer is referenced.
1183 		 *
1184 		 * We could be racing a buffer release, in which case
1185 		 * node->buffer may become NULL while we are blocked
1186 		 * referencing the buffer.
1187 		 */
1188 		if ((buffer = node->buffer) != NULL) {
1189 			error = hammer_ref_buffer(buffer);
1190 			if (error == 0 && node->buffer == NULL) {
1191 				TAILQ_INSERT_TAIL(&buffer->clist,
1192 						  node, entry);
1193 				node->buffer = buffer;
1194 			}
1195 		} else {
1196 			buf_offset = node->node_offset & ~HAMMER_BUFMASK64;
1197 			buffer = hammer_get_buffer(node->hmp, buf_offset,
1198 						   HAMMER_BUFSIZE, 0, &error);
1199 			if (buffer) {
1200 				KKASSERT(error == 0);
1201 				TAILQ_INSERT_TAIL(&buffer->clist,
1202 						  node, entry);
1203 				node->buffer = buffer;
1204 			}
1205 		}
1206 		if (error)
1207 			goto failed;
1208 		node->ondisk = (void *)((char *)buffer->ondisk +
1209 				        (node->node_offset & HAMMER_BUFMASK));
1210 
1211 		/*
1212 		 * Check CRC.  NOTE: Neither flag is set and the CRC is not
1213 		 * generated on new B-Tree nodes.
1214 		 */
1215 		if (isnew == 0 &&
1216 		    (node->flags & HAMMER_NODE_CRCANY) == 0) {
1217 			if (hammer_crc_test_btree(node->ondisk) == 0) {
1218 				if (hammer_debug_critical)
1219 					Debugger("CRC FAILED: B-TREE NODE");
1220 				node->flags |= HAMMER_NODE_CRCBAD;
1221 			} else {
1222 				node->flags |= HAMMER_NODE_CRCGOOD;
1223 			}
1224 		}
1225 	}
1226 	if (node->flags & HAMMER_NODE_CRCBAD) {
1227 		if (trans->flags & HAMMER_TRANSF_CRCDOM)
1228 			error = EDOM;
1229 		else
1230 			error = EIO;
1231 	}
1232 failed:
1233 	--node->loading;
1234 	hammer_unlock(&node->lock);
1235 	return (error);
1236 }
1237 
1238 /*
1239  * Safely reference a node, interlock against flushes via the IO subsystem.
1240  */
1241 hammer_node_t
1242 hammer_ref_node_safe(hammer_transaction_t trans, hammer_node_cache_t cache,
1243 		     int *errorp)
1244 {
1245 	hammer_node_t node;
1246 
1247 	node = cache->node;
1248 	if (node != NULL) {
1249 		hammer_ref(&node->lock);
1250 		if (node->ondisk) {
1251 			if (node->flags & HAMMER_NODE_CRCBAD) {
1252 				if (trans->flags & HAMMER_TRANSF_CRCDOM)
1253 					*errorp = EDOM;
1254 				else
1255 					*errorp = EIO;
1256 			} else {
1257 				*errorp = 0;
1258 			}
1259 		} else {
1260 			*errorp = hammer_load_node(trans, node, 0);
1261 		}
1262 		if (*errorp) {
1263 			hammer_rel_node(node);
1264 			node = NULL;
1265 		}
1266 	} else {
1267 		*errorp = ENOENT;
1268 	}
1269 	return(node);
1270 }
1271 
1272 /*
1273  * Release a hammer_node.  On the last release the node dereferences
1274  * its underlying buffer and may or may not be destroyed.
1275  */
1276 void
1277 hammer_rel_node(hammer_node_t node)
1278 {
1279 	hammer_buffer_t buffer;
1280 
1281 	/*
1282 	 * If this isn't the last ref just decrement the ref count and
1283 	 * return.
1284 	 */
1285 	if (node->lock.refs > 1) {
1286 		hammer_unref(&node->lock);
1287 		return;
1288 	}
1289 
1290 	/*
1291 	 * If there is no ondisk info or no buffer the node failed to load,
1292 	 * remove the last reference and destroy the node.
1293 	 */
1294 	if (node->ondisk == NULL) {
1295 		hammer_unref(&node->lock);
1296 		hammer_flush_node(node);
1297 		/* node is stale now */
1298 		return;
1299 	}
1300 
1301 	/*
1302 	 * Do not disassociate the node from the buffer if it represents
1303 	 * a modified B-Tree node that still needs its crc to be generated.
1304 	 */
1305 	if (node->flags & HAMMER_NODE_NEEDSCRC)
1306 		return;
1307 
1308 	/*
1309 	 * Do final cleanups and then either destroy the node and leave it
1310 	 * passively cached.  The buffer reference is removed regardless.
1311 	 */
1312 	buffer = node->buffer;
1313 	node->ondisk = NULL;
1314 
1315 	if ((node->flags & HAMMER_NODE_FLUSH) == 0) {
1316 		hammer_unref(&node->lock);
1317 		hammer_rel_buffer(buffer, 0);
1318 		return;
1319 	}
1320 
1321 	/*
1322 	 * Destroy the node.
1323 	 */
1324 	hammer_unref(&node->lock);
1325 	hammer_flush_node(node);
1326 	/* node is stale */
1327 	hammer_rel_buffer(buffer, 0);
1328 }
1329 
1330 /*
1331  * Free space on-media associated with a B-Tree node.
1332  */
1333 void
1334 hammer_delete_node(hammer_transaction_t trans, hammer_node_t node)
1335 {
1336 	KKASSERT((node->flags & HAMMER_NODE_DELETED) == 0);
1337 	node->flags |= HAMMER_NODE_DELETED;
1338 	hammer_blockmap_free(trans, node->node_offset, sizeof(*node->ondisk));
1339 }
1340 
1341 /*
1342  * Passively cache a referenced hammer_node.  The caller may release
1343  * the node on return.
1344  */
1345 void
1346 hammer_cache_node(hammer_node_cache_t cache, hammer_node_t node)
1347 {
1348 	/*
1349 	 * If the node doesn't exist, or is being deleted, don't cache it!
1350 	 *
1351 	 * The node can only ever be NULL in the I/O failure path.
1352 	 */
1353 	if (node == NULL || (node->flags & HAMMER_NODE_DELETED))
1354 		return;
1355 	if (cache->node == node)
1356 		return;
1357 	while (cache->node)
1358 		hammer_uncache_node(cache);
1359 	if (node->flags & HAMMER_NODE_DELETED)
1360 		return;
1361 	cache->node = node;
1362 	TAILQ_INSERT_TAIL(&node->cache_list, cache, entry);
1363 }
1364 
1365 void
1366 hammer_uncache_node(hammer_node_cache_t cache)
1367 {
1368 	hammer_node_t node;
1369 
1370 	if ((node = cache->node) != NULL) {
1371 		TAILQ_REMOVE(&node->cache_list, cache, entry);
1372 		cache->node = NULL;
1373 		if (TAILQ_EMPTY(&node->cache_list))
1374 			hammer_flush_node(node);
1375 	}
1376 }
1377 
1378 /*
1379  * Remove a node's cache references and destroy the node if it has no
1380  * other references or backing store.
1381  */
1382 void
1383 hammer_flush_node(hammer_node_t node)
1384 {
1385 	hammer_node_cache_t cache;
1386 	hammer_buffer_t buffer;
1387 	hammer_mount_t hmp = node->hmp;
1388 
1389 	while ((cache = TAILQ_FIRST(&node->cache_list)) != NULL) {
1390 		TAILQ_REMOVE(&node->cache_list, cache, entry);
1391 		cache->node = NULL;
1392 	}
1393 	if (node->lock.refs == 0 && node->ondisk == NULL) {
1394 		KKASSERT((node->flags & HAMMER_NODE_NEEDSCRC) == 0);
1395 		RB_REMOVE(hammer_nod_rb_tree, &node->hmp->rb_nods_root, node);
1396 		if ((buffer = node->buffer) != NULL) {
1397 			node->buffer = NULL;
1398 			TAILQ_REMOVE(&buffer->clist, node, entry);
1399 			/* buffer is unreferenced because ondisk is NULL */
1400 		}
1401 		--hammer_count_nodes;
1402 		kfree(node, hmp->m_misc);
1403 	}
1404 }
1405 
1406 /*
1407  * Flush passively cached B-Tree nodes associated with this buffer.
1408  * This is only called when the buffer is about to be destroyed, so
1409  * none of the nodes should have any references.  The buffer is locked.
1410  *
1411  * We may be interlocked with the buffer.
1412  */
1413 void
1414 hammer_flush_buffer_nodes(hammer_buffer_t buffer)
1415 {
1416 	hammer_node_t node;
1417 
1418 	while ((node = TAILQ_FIRST(&buffer->clist)) != NULL) {
1419 		KKASSERT(node->ondisk == NULL);
1420 		KKASSERT((node->flags & HAMMER_NODE_NEEDSCRC) == 0);
1421 
1422 		if (node->lock.refs == 0) {
1423 			hammer_ref(&node->lock);
1424 			node->flags |= HAMMER_NODE_FLUSH;
1425 			hammer_rel_node(node);
1426 		} else {
1427 			KKASSERT(node->loading != 0);
1428 			KKASSERT(node->buffer != NULL);
1429 			buffer = node->buffer;
1430 			node->buffer = NULL;
1431 			TAILQ_REMOVE(&buffer->clist, node, entry);
1432 			/* buffer is unreferenced because ondisk is NULL */
1433 		}
1434 	}
1435 }
1436 
1437 
1438 /************************************************************************
1439  *				ALLOCATORS				*
1440  ************************************************************************/
1441 
1442 /*
1443  * Allocate a B-Tree node.
1444  */
1445 hammer_node_t
1446 hammer_alloc_btree(hammer_transaction_t trans, hammer_off_t hint, int *errorp)
1447 {
1448 	hammer_buffer_t buffer = NULL;
1449 	hammer_node_t node = NULL;
1450 	hammer_off_t node_offset;
1451 
1452 	node_offset = hammer_blockmap_alloc(trans, HAMMER_ZONE_BTREE_INDEX,
1453 					    sizeof(struct hammer_node_ondisk),
1454 					    hint, errorp);
1455 	if (*errorp == 0) {
1456 		node = hammer_get_node(trans, node_offset, 1, errorp);
1457 		hammer_modify_node_noundo(trans, node);
1458 		bzero(node->ondisk, sizeof(*node->ondisk));
1459 		hammer_modify_node_done(node);
1460 	}
1461 	if (buffer)
1462 		hammer_rel_buffer(buffer, 0);
1463 	return(node);
1464 }
1465 
1466 /*
1467  * Allocate data.  If the address of a data buffer is supplied then
1468  * any prior non-NULL *data_bufferp will be released and *data_bufferp
1469  * will be set to the related buffer.  The caller must release it when
1470  * finally done.  The initial *data_bufferp should be set to NULL by
1471  * the caller.
1472  *
1473  * The caller is responsible for making hammer_modify*() calls on the
1474  * *data_bufferp.
1475  */
1476 void *
1477 hammer_alloc_data(hammer_transaction_t trans, int32_t data_len,
1478 		  u_int16_t rec_type, hammer_off_t *data_offsetp,
1479 		  struct hammer_buffer **data_bufferp,
1480 		  hammer_off_t hint, int *errorp)
1481 {
1482 	void *data;
1483 	int zone;
1484 
1485 	/*
1486 	 * Allocate data
1487 	 */
1488 	if (data_len) {
1489 		switch(rec_type) {
1490 		case HAMMER_RECTYPE_INODE:
1491 		case HAMMER_RECTYPE_DIRENTRY:
1492 		case HAMMER_RECTYPE_EXT:
1493 		case HAMMER_RECTYPE_FIX:
1494 		case HAMMER_RECTYPE_PFS:
1495 		case HAMMER_RECTYPE_SNAPSHOT:
1496 		case HAMMER_RECTYPE_CONFIG:
1497 			zone = HAMMER_ZONE_META_INDEX;
1498 			break;
1499 		case HAMMER_RECTYPE_DATA:
1500 		case HAMMER_RECTYPE_DB:
1501 			if (data_len <= HAMMER_BUFSIZE / 2) {
1502 				zone = HAMMER_ZONE_SMALL_DATA_INDEX;
1503 			} else {
1504 				data_len = (data_len + HAMMER_BUFMASK) &
1505 					   ~HAMMER_BUFMASK;
1506 				zone = HAMMER_ZONE_LARGE_DATA_INDEX;
1507 			}
1508 			break;
1509 		default:
1510 			panic("hammer_alloc_data: rec_type %04x unknown",
1511 			      rec_type);
1512 			zone = 0;	/* NOT REACHED */
1513 			break;
1514 		}
1515 		*data_offsetp = hammer_blockmap_alloc(trans, zone, data_len,
1516 						      hint, errorp);
1517 	} else {
1518 		*data_offsetp = 0;
1519 	}
1520 	if (*errorp == 0 && data_bufferp) {
1521 		if (data_len) {
1522 			data = hammer_bread_ext(trans->hmp, *data_offsetp,
1523 						data_len, errorp, data_bufferp);
1524 		} else {
1525 			data = NULL;
1526 		}
1527 	} else {
1528 		data = NULL;
1529 	}
1530 	return(data);
1531 }
1532 
1533 /*
1534  * Sync dirty buffers to the media and clean-up any loose ends.
1535  *
1536  * These functions do not start the flusher going, they simply
1537  * queue everything up to the flusher.
1538  */
1539 static int hammer_sync_scan1(struct mount *mp, struct vnode *vp, void *data);
1540 static int hammer_sync_scan2(struct mount *mp, struct vnode *vp, void *data);
1541 
1542 int
1543 hammer_queue_inodes_flusher(hammer_mount_t hmp, int waitfor)
1544 {
1545 	struct hammer_sync_info info;
1546 
1547 	info.error = 0;
1548 	info.waitfor = waitfor;
1549 	if (waitfor == MNT_WAIT) {
1550 		vmntvnodescan(hmp->mp, VMSC_GETVP|VMSC_ONEPASS,
1551 			      hammer_sync_scan1, hammer_sync_scan2, &info);
1552 	} else {
1553 		vmntvnodescan(hmp->mp, VMSC_GETVP|VMSC_ONEPASS|VMSC_NOWAIT,
1554 			      hammer_sync_scan1, hammer_sync_scan2, &info);
1555 	}
1556 	return(info.error);
1557 }
1558 
1559 /*
1560  * Filesystem sync.  If doing a synchronous sync make a second pass on
1561  * the vnodes in case any were already flushing during the first pass,
1562  * and activate the flusher twice (the second time brings the UNDO FIFO's
1563  * start position up to the end position after the first call).
1564  */
1565 int
1566 hammer_sync_hmp(hammer_mount_t hmp, int waitfor)
1567 {
1568 	struct hammer_sync_info info;
1569 
1570 	info.error = 0;
1571 	info.waitfor = MNT_NOWAIT;
1572 	vmntvnodescan(hmp->mp, VMSC_GETVP|VMSC_NOWAIT,
1573 		      hammer_sync_scan1, hammer_sync_scan2, &info);
1574 	if (info.error == 0 && waitfor == MNT_WAIT) {
1575 		info.waitfor = waitfor;
1576 		vmntvnodescan(hmp->mp, VMSC_GETVP,
1577 			      hammer_sync_scan1, hammer_sync_scan2, &info);
1578 	}
1579         if (waitfor == MNT_WAIT) {
1580                 hammer_flusher_sync(hmp);
1581                 hammer_flusher_sync(hmp);
1582 	} else {
1583                 hammer_flusher_async(hmp, NULL);
1584                 hammer_flusher_async(hmp, NULL);
1585 	}
1586 	return(info.error);
1587 }
1588 
1589 static int
1590 hammer_sync_scan1(struct mount *mp, struct vnode *vp, void *data)
1591 {
1592 	struct hammer_inode *ip;
1593 
1594 	ip = VTOI(vp);
1595 	if (vp->v_type == VNON || ip == NULL ||
1596 	    ((ip->flags & HAMMER_INODE_MODMASK) == 0 &&
1597 	     RB_EMPTY(&vp->v_rbdirty_tree))) {
1598 		return(-1);
1599 	}
1600 	return(0);
1601 }
1602 
1603 static int
1604 hammer_sync_scan2(struct mount *mp, struct vnode *vp, void *data)
1605 {
1606 	struct hammer_sync_info *info = data;
1607 	struct hammer_inode *ip;
1608 	int error;
1609 
1610 	ip = VTOI(vp);
1611 	if (vp->v_type == VNON || vp->v_type == VBAD ||
1612 	    ((ip->flags & HAMMER_INODE_MODMASK) == 0 &&
1613 	     RB_EMPTY(&vp->v_rbdirty_tree))) {
1614 		return(0);
1615 	}
1616 	error = VOP_FSYNC(vp, MNT_NOWAIT, 0);
1617 	if (error)
1618 		info->error = error;
1619 	return(0);
1620 }
1621 
1622