xref: /netbsd-src/sys/kern/vfs_wapbl.c (revision 9573673d78c64ea1eac42d7f2e9521be89932ae5)
1 /*	$NetBSD: vfs_wapbl.c,v 1.64 2015/11/15 03:09:39 pgoyette Exp $	*/
2 
3 /*-
4  * Copyright (c) 2003, 2008, 2009 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Wasabi Systems, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29  * POSSIBILITY OF SUCH DAMAGE.
30  */
31 
32 /*
33  * This implements file system independent write ahead filesystem logging.
34  */
35 
36 #define WAPBL_INTERNAL
37 
38 #include <sys/cdefs.h>
39 __KERNEL_RCSID(0, "$NetBSD: vfs_wapbl.c,v 1.64 2015/11/15 03:09:39 pgoyette Exp $");
40 
41 #include <sys/param.h>
42 #include <sys/bitops.h>
43 
44 #ifdef _KERNEL
45 #include <sys/param.h>
46 #include <sys/namei.h>
47 #include <sys/proc.h>
48 #include <sys/sysctl.h>
49 #include <sys/uio.h>
50 #include <sys/vnode.h>
51 #include <sys/file.h>
52 #include <sys/module.h>
53 #include <sys/resourcevar.h>
54 #include <sys/conf.h>
55 #include <sys/mount.h>
56 #include <sys/kernel.h>
57 #include <sys/kauth.h>
58 #include <sys/mutex.h>
59 #include <sys/atomic.h>
60 #include <sys/wapbl.h>
61 #include <sys/wapbl_replay.h>
62 
63 #include <miscfs/specfs/specdev.h>
64 
65 #define	wapbl_alloc(s) kmem_alloc((s), KM_SLEEP)
66 #define	wapbl_free(a, s) kmem_free((a), (s))
67 #define	wapbl_calloc(n, s) kmem_zalloc((n)*(s), KM_SLEEP)
68 
69 static struct sysctllog *wapbl_sysctl;
70 static int wapbl_flush_disk_cache = 1;
71 static int wapbl_verbose_commit = 0;
72 
73 static inline size_t wapbl_space_free(size_t, off_t, off_t);
74 
75 #else /* !_KERNEL */
76 #include <assert.h>
77 #include <errno.h>
78 #include <stdio.h>
79 #include <stdbool.h>
80 #include <stdlib.h>
81 #include <string.h>
82 
83 #include <sys/time.h>
84 #include <sys/wapbl.h>
85 #include <sys/wapbl_replay.h>
86 
87 #define	KDASSERT(x) assert(x)
88 #define	KASSERT(x) assert(x)
89 #define	wapbl_alloc(s) malloc(s)
90 #define	wapbl_free(a, s) free(a)
91 #define	wapbl_calloc(n, s) calloc((n), (s))
92 
93 #endif /* !_KERNEL */
94 
95 /*
96  * INTERNAL DATA STRUCTURES
97  */
98 
99 /*
100  * This structure holds per-mount log information.
101  *
102  * Legend:	a = atomic access only
103  *		r = read-only after init
104  *		l = rwlock held
105  *		m = mutex held
106  *		lm = rwlock held writing or mutex held
107  *		u = unlocked access ok
108  *		b = bufcache_lock held
109  */
110 LIST_HEAD(wapbl_ino_head, wapbl_ino);
111 struct wapbl {
112 	struct vnode *wl_logvp;	/* r:	log here */
113 	struct vnode *wl_devvp;	/* r:	log on this device */
114 	struct mount *wl_mount;	/* r:	mountpoint wl is associated with */
115 	daddr_t wl_logpbn;	/* r:	Physical block number of start of log */
116 	int wl_log_dev_bshift;	/* r:	logarithm of device block size of log
117 					device */
118 	int wl_fs_dev_bshift;	/* r:	logarithm of device block size of
119 					filesystem device */
120 
121 	unsigned wl_lock_count;	/* m:	Count of transactions in progress */
122 
123 	size_t wl_circ_size; 	/* r:	Number of bytes in buffer of log */
124 	size_t wl_circ_off;	/* r:	Number of bytes reserved at start */
125 
126 	size_t wl_bufcount_max;	/* r:	Number of buffers reserved for log */
127 	size_t wl_bufbytes_max;	/* r:	Number of buf bytes reserved for log */
128 
129 	off_t wl_head;		/* l:	Byte offset of log head */
130 	off_t wl_tail;		/* l:	Byte offset of log tail */
131 	/*
132 	 * head == tail == 0 means log is empty
133 	 * head == tail != 0 means log is full
134 	 * see assertions in wapbl_advance() for other boundary conditions.
135 	 * only truncate moves the tail, except when flush sets it to
136 	 * wl_header_size only flush moves the head, except when truncate
137 	 * sets it to 0.
138 	 */
139 
140 	struct wapbl_wc_header *wl_wc_header;	/* l	*/
141 	void *wl_wc_scratch;	/* l:	scratch space (XXX: por que?!?) */
142 
143 	kmutex_t wl_mtx;	/* u:	short-term lock */
144 	krwlock_t wl_rwlock;	/* u:	File system transaction lock */
145 
146 	/*
147 	 * Must be held while accessing
148 	 * wl_count or wl_bufs or head or tail
149 	 */
150 
151 	/*
152 	 * Callback called from within the flush routine to flush any extra
153 	 * bits.  Note that flush may be skipped without calling this if
154 	 * there are no outstanding buffers in the transaction.
155 	 */
156 #if _KERNEL
157 	wapbl_flush_fn_t wl_flush;	/* r	*/
158 	wapbl_flush_fn_t wl_flush_abort;/* r	*/
159 #endif
160 
161 	size_t wl_bufbytes;	/* m:	Byte count of pages in wl_bufs */
162 	size_t wl_bufcount;	/* m:	Count of buffers in wl_bufs */
163 	size_t wl_bcount;	/* m:	Total bcount of wl_bufs */
164 
165 	LIST_HEAD(, buf) wl_bufs; /* m:	Buffers in current transaction */
166 
167 	kcondvar_t wl_reclaimable_cv;	/* m (obviously) */
168 	size_t wl_reclaimable_bytes; /* m:	Amount of space available for
169 						reclamation by truncate */
170 	int wl_error_count;	/* m:	# of wl_entries with errors */
171 	size_t wl_reserved_bytes; /* never truncate log smaller than this */
172 
173 #ifdef WAPBL_DEBUG_BUFBYTES
174 	size_t wl_unsynced_bufbytes; /* Byte count of unsynced buffers */
175 #endif
176 
177 	daddr_t *wl_deallocblks;/* lm:	address of block */
178 	int *wl_dealloclens;	/* lm:	size of block */
179 	int wl_dealloccnt;	/* lm:	total count */
180 	int wl_dealloclim;	/* l:	max count */
181 
182 	/* hashtable of inode numbers for allocated but unlinked inodes */
183 	/* synch ??? */
184 	struct wapbl_ino_head *wl_inohash;
185 	u_long wl_inohashmask;
186 	int wl_inohashcnt;
187 
188 	SIMPLEQ_HEAD(, wapbl_entry) wl_entries; /* On disk transaction
189 						   accounting */
190 
191 	u_char *wl_buffer;	/* l:   buffer for wapbl_buffered_write() */
192 	daddr_t wl_buffer_dblk;	/* l:   buffer disk block address */
193 	size_t wl_buffer_used;	/* l:   buffer current use */
194 };
195 
196 #ifdef WAPBL_DEBUG_PRINT
197 int wapbl_debug_print = WAPBL_DEBUG_PRINT;
198 #endif
199 
200 /****************************************************************/
201 #ifdef _KERNEL
202 
203 #ifdef WAPBL_DEBUG
204 struct wapbl *wapbl_debug_wl;
205 #endif
206 
207 static int wapbl_write_commit(struct wapbl *wl, off_t head, off_t tail);
208 static int wapbl_write_blocks(struct wapbl *wl, off_t *offp);
209 static int wapbl_write_revocations(struct wapbl *wl, off_t *offp);
210 static int wapbl_write_inodes(struct wapbl *wl, off_t *offp);
211 #endif /* _KERNEL */
212 
213 static int wapbl_replay_process(struct wapbl_replay *wr, off_t, off_t);
214 
215 static inline size_t wapbl_space_used(size_t avail, off_t head,
216 	off_t tail);
217 
218 #ifdef _KERNEL
219 
220 static struct pool wapbl_entry_pool;
221 
222 #define	WAPBL_INODETRK_SIZE 83
223 static int wapbl_ino_pool_refcount;
224 static struct pool wapbl_ino_pool;
225 struct wapbl_ino {
226 	LIST_ENTRY(wapbl_ino) wi_hash;
227 	ino_t wi_ino;
228 	mode_t wi_mode;
229 };
230 
231 static void wapbl_inodetrk_init(struct wapbl *wl, u_int size);
232 static void wapbl_inodetrk_free(struct wapbl *wl);
233 static struct wapbl_ino *wapbl_inodetrk_get(struct wapbl *wl, ino_t ino);
234 
235 static size_t wapbl_transaction_len(struct wapbl *wl);
236 static inline size_t wapbl_transaction_inodes_len(struct wapbl *wl);
237 
238 #if 0
239 int wapbl_replay_verify(struct wapbl_replay *, struct vnode *);
240 #endif
241 
242 static int wapbl_replay_isopen1(struct wapbl_replay *);
243 
244 /*
245  * This is useful for debugging.  If set, the log will
246  * only be truncated when necessary.
247  */
248 int wapbl_lazy_truncate = 0;
249 
250 struct wapbl_ops wapbl_ops = {
251 	.wo_wapbl_discard	= wapbl_discard,
252 	.wo_wapbl_replay_isopen	= wapbl_replay_isopen1,
253 	.wo_wapbl_replay_can_read = wapbl_replay_can_read,
254 	.wo_wapbl_replay_read	= wapbl_replay_read,
255 	.wo_wapbl_add_buf	= wapbl_add_buf,
256 	.wo_wapbl_remove_buf	= wapbl_remove_buf,
257 	.wo_wapbl_resize_buf	= wapbl_resize_buf,
258 	.wo_wapbl_begin		= wapbl_begin,
259 	.wo_wapbl_end		= wapbl_end,
260 	.wo_wapbl_junlock_assert= wapbl_junlock_assert,
261 
262 	/* XXX: the following is only used to say "this is a wapbl buf" */
263 	.wo_wapbl_biodone	= wapbl_biodone,
264 };
265 
266 static int
267 wapbl_sysctl_init(void)
268 {
269 	int rv;
270 	const struct sysctlnode *rnode, *cnode;
271 
272 	wapbl_sysctl = NULL;
273 
274 	rv = sysctl_createv(&wapbl_sysctl, 0, NULL, &rnode,
275 		       CTLFLAG_PERMANENT,
276 		       CTLTYPE_NODE, "wapbl",
277 		       SYSCTL_DESCR("WAPBL journaling options"),
278 		       NULL, 0, NULL, 0,
279 		       CTL_VFS, CTL_CREATE, CTL_EOL);
280 	if (rv)
281 		return rv;
282 
283 	rv = sysctl_createv(&wapbl_sysctl, 0, &rnode, &cnode,
284 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
285 		       CTLTYPE_INT, "flush_disk_cache",
286 		       SYSCTL_DESCR("flush disk cache"),
287 		       NULL, 0, &wapbl_flush_disk_cache, 0,
288 		       CTL_CREATE, CTL_EOL);
289 	if (rv)
290 		return rv;
291 
292 	rv = sysctl_createv(&wapbl_sysctl, 0, &rnode, &cnode,
293 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
294 		       CTLTYPE_INT, "verbose_commit",
295 		       SYSCTL_DESCR("show time and size of wapbl log commits"),
296 		       NULL, 0, &wapbl_verbose_commit, 0,
297 		       CTL_CREATE, CTL_EOL);
298 	return rv;
299 }
300 
301 static void
302 wapbl_init(void)
303 {
304 
305 	pool_init(&wapbl_entry_pool, sizeof(struct wapbl_entry), 0, 0, 0,
306 	    "wapblentrypl", &pool_allocator_kmem, IPL_VM);
307 
308 	wapbl_sysctl_init();
309 }
310 
311 static int
312 wapbl_fini(bool interface)
313 {
314 
315 	if (wapbl_sysctl != NULL)
316 		 sysctl_teardown(&wapbl_sysctl);
317 
318 	pool_destroy(&wapbl_entry_pool);
319 
320 	return 0;
321 }
322 
323 static int
324 wapbl_start_flush_inodes(struct wapbl *wl, struct wapbl_replay *wr)
325 {
326 	int error, i;
327 
328 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY,
329 	    ("wapbl_start: reusing log with %d inodes\n", wr->wr_inodescnt));
330 
331 	/*
332 	 * Its only valid to reuse the replay log if its
333 	 * the same as the new log we just opened.
334 	 */
335 	KDASSERT(!wapbl_replay_isopen(wr));
336 	KASSERT(wl->wl_devvp->v_type == VBLK);
337 	KASSERT(wr->wr_devvp->v_type == VBLK);
338 	KASSERT(wl->wl_devvp->v_rdev == wr->wr_devvp->v_rdev);
339 	KASSERT(wl->wl_logpbn == wr->wr_logpbn);
340 	KASSERT(wl->wl_circ_size == wr->wr_circ_size);
341 	KASSERT(wl->wl_circ_off == wr->wr_circ_off);
342 	KASSERT(wl->wl_log_dev_bshift == wr->wr_log_dev_bshift);
343 	KASSERT(wl->wl_fs_dev_bshift == wr->wr_fs_dev_bshift);
344 
345 	wl->wl_wc_header->wc_generation = wr->wr_generation + 1;
346 
347 	for (i = 0; i < wr->wr_inodescnt; i++)
348 		wapbl_register_inode(wl, wr->wr_inodes[i].wr_inumber,
349 		    wr->wr_inodes[i].wr_imode);
350 
351 	/* Make sure new transaction won't overwrite old inodes list */
352 	KDASSERT(wapbl_transaction_len(wl) <=
353 	    wapbl_space_free(wl->wl_circ_size, wr->wr_inodeshead,
354 	    wr->wr_inodestail));
355 
356 	wl->wl_head = wl->wl_tail = wr->wr_inodeshead;
357 	wl->wl_reclaimable_bytes = wl->wl_reserved_bytes =
358 	    wapbl_transaction_len(wl);
359 
360 	error = wapbl_write_inodes(wl, &wl->wl_head);
361 	if (error)
362 		return error;
363 
364 	KASSERT(wl->wl_head != wl->wl_tail);
365 	KASSERT(wl->wl_head != 0);
366 
367 	return 0;
368 }
369 
370 int
371 wapbl_start(struct wapbl ** wlp, struct mount *mp, struct vnode *vp,
372 	daddr_t off, size_t count, size_t blksize, struct wapbl_replay *wr,
373 	wapbl_flush_fn_t flushfn, wapbl_flush_fn_t flushabortfn)
374 {
375 	struct wapbl *wl;
376 	struct vnode *devvp;
377 	daddr_t logpbn;
378 	int error;
379 	int log_dev_bshift = ilog2(blksize);
380 	int fs_dev_bshift = log_dev_bshift;
381 	int run;
382 
383 	WAPBL_PRINTF(WAPBL_PRINT_OPEN, ("wapbl_start: vp=%p off=%" PRId64
384 	    " count=%zu blksize=%zu\n", vp, off, count, blksize));
385 
386 	if (log_dev_bshift > fs_dev_bshift) {
387 		WAPBL_PRINTF(WAPBL_PRINT_OPEN,
388 			("wapbl: log device's block size cannot be larger "
389 			 "than filesystem's\n"));
390 		/*
391 		 * Not currently implemented, although it could be if
392 		 * needed someday.
393 		 */
394 		return ENOSYS;
395 	}
396 
397 	if (off < 0)
398 		return EINVAL;
399 
400 	if (blksize < DEV_BSIZE)
401 		return EINVAL;
402 	if (blksize % DEV_BSIZE)
403 		return EINVAL;
404 
405 	/* XXXTODO: verify that the full load is writable */
406 
407 	/*
408 	 * XXX check for minimum log size
409 	 * minimum is governed by minimum amount of space
410 	 * to complete a transaction. (probably truncate)
411 	 */
412 	/* XXX for now pick something minimal */
413 	if ((count * blksize) < MAXPHYS) {
414 		return ENOSPC;
415 	}
416 
417 	if ((error = VOP_BMAP(vp, off, &devvp, &logpbn, &run)) != 0) {
418 		return error;
419 	}
420 
421 	wl = wapbl_calloc(1, sizeof(*wl));
422 	rw_init(&wl->wl_rwlock);
423 	mutex_init(&wl->wl_mtx, MUTEX_DEFAULT, IPL_NONE);
424 	cv_init(&wl->wl_reclaimable_cv, "wapblrec");
425 	LIST_INIT(&wl->wl_bufs);
426 	SIMPLEQ_INIT(&wl->wl_entries);
427 
428 	wl->wl_logvp = vp;
429 	wl->wl_devvp = devvp;
430 	wl->wl_mount = mp;
431 	wl->wl_logpbn = logpbn;
432 	wl->wl_log_dev_bshift = log_dev_bshift;
433 	wl->wl_fs_dev_bshift = fs_dev_bshift;
434 
435 	wl->wl_flush = flushfn;
436 	wl->wl_flush_abort = flushabortfn;
437 
438 	/* Reserve two log device blocks for the commit headers */
439 	wl->wl_circ_off = 2<<wl->wl_log_dev_bshift;
440 	wl->wl_circ_size = ((count * blksize) - wl->wl_circ_off);
441 	/* truncate the log usage to a multiple of log_dev_bshift */
442 	wl->wl_circ_size >>= wl->wl_log_dev_bshift;
443 	wl->wl_circ_size <<= wl->wl_log_dev_bshift;
444 
445 	/*
446 	 * wl_bufbytes_max limits the size of the in memory transaction space.
447 	 * - Since buffers are allocated and accounted for in units of
448 	 *   PAGE_SIZE it is required to be a multiple of PAGE_SIZE
449 	 *   (i.e. 1<<PAGE_SHIFT)
450 	 * - Since the log device has to be written in units of
451 	 *   1<<wl_log_dev_bshift it is required to be a mulitple of
452 	 *   1<<wl_log_dev_bshift.
453 	 * - Since filesystem will provide data in units of 1<<wl_fs_dev_bshift,
454 	 *   it is convenient to be a multiple of 1<<wl_fs_dev_bshift.
455 	 * Therefore it must be multiple of the least common multiple of those
456 	 * three quantities.  Fortunately, all of those quantities are
457 	 * guaranteed to be a power of two, and the least common multiple of
458 	 * a set of numbers which are all powers of two is simply the maximum
459 	 * of those numbers.  Finally, the maximum logarithm of a power of two
460 	 * is the same as the log of the maximum power of two.  So we can do
461 	 * the following operations to size wl_bufbytes_max:
462 	 */
463 
464 	/* XXX fix actual number of pages reserved per filesystem. */
465 	wl->wl_bufbytes_max = MIN(wl->wl_circ_size, buf_memcalc() / 2);
466 
467 	/* Round wl_bufbytes_max to the largest power of two constraint */
468 	wl->wl_bufbytes_max >>= PAGE_SHIFT;
469 	wl->wl_bufbytes_max <<= PAGE_SHIFT;
470 	wl->wl_bufbytes_max >>= wl->wl_log_dev_bshift;
471 	wl->wl_bufbytes_max <<= wl->wl_log_dev_bshift;
472 	wl->wl_bufbytes_max >>= wl->wl_fs_dev_bshift;
473 	wl->wl_bufbytes_max <<= wl->wl_fs_dev_bshift;
474 
475 	/* XXX maybe use filesystem fragment size instead of 1024 */
476 	/* XXX fix actual number of buffers reserved per filesystem. */
477 	wl->wl_bufcount_max = (nbuf / 2) * 1024;
478 
479 	/* XXX tie this into resource estimation */
480 	wl->wl_dealloclim = wl->wl_bufbytes_max / mp->mnt_stat.f_bsize / 2;
481 
482 	wl->wl_deallocblks = wapbl_alloc(sizeof(*wl->wl_deallocblks) *
483 	    wl->wl_dealloclim);
484 	wl->wl_dealloclens = wapbl_alloc(sizeof(*wl->wl_dealloclens) *
485 	    wl->wl_dealloclim);
486 
487 	wl->wl_buffer = wapbl_alloc(MAXPHYS);
488 	wl->wl_buffer_used = 0;
489 
490 	wapbl_inodetrk_init(wl, WAPBL_INODETRK_SIZE);
491 
492 	/* Initialize the commit header */
493 	{
494 		struct wapbl_wc_header *wc;
495 		size_t len = 1 << wl->wl_log_dev_bshift;
496 		wc = wapbl_calloc(1, len);
497 		wc->wc_type = WAPBL_WC_HEADER;
498 		wc->wc_len = len;
499 		wc->wc_circ_off = wl->wl_circ_off;
500 		wc->wc_circ_size = wl->wl_circ_size;
501 		/* XXX wc->wc_fsid */
502 		wc->wc_log_dev_bshift = wl->wl_log_dev_bshift;
503 		wc->wc_fs_dev_bshift = wl->wl_fs_dev_bshift;
504 		wl->wl_wc_header = wc;
505 		wl->wl_wc_scratch = wapbl_alloc(len);
506 	}
507 
508 	/*
509 	 * if there was an existing set of unlinked but
510 	 * allocated inodes, preserve it in the new
511 	 * log.
512 	 */
513 	if (wr && wr->wr_inodescnt) {
514 		error = wapbl_start_flush_inodes(wl, wr);
515 		if (error)
516 			goto errout;
517 	}
518 
519 	error = wapbl_write_commit(wl, wl->wl_head, wl->wl_tail);
520 	if (error) {
521 		goto errout;
522 	}
523 
524 	*wlp = wl;
525 #if defined(WAPBL_DEBUG)
526 	wapbl_debug_wl = wl;
527 #endif
528 
529 	return 0;
530  errout:
531 	wapbl_discard(wl);
532 	wapbl_free(wl->wl_wc_scratch, wl->wl_wc_header->wc_len);
533 	wapbl_free(wl->wl_wc_header, wl->wl_wc_header->wc_len);
534 	wapbl_free(wl->wl_deallocblks,
535 	    sizeof(*wl->wl_deallocblks) * wl->wl_dealloclim);
536 	wapbl_free(wl->wl_dealloclens,
537 	    sizeof(*wl->wl_dealloclens) * wl->wl_dealloclim);
538 	wapbl_free(wl->wl_buffer, MAXPHYS);
539 	wapbl_inodetrk_free(wl);
540 	wapbl_free(wl, sizeof(*wl));
541 
542 	return error;
543 }
544 
545 /*
546  * Like wapbl_flush, only discards the transaction
547  * completely
548  */
549 
550 void
551 wapbl_discard(struct wapbl *wl)
552 {
553 	struct wapbl_entry *we;
554 	struct buf *bp;
555 	int i;
556 
557 	/*
558 	 * XXX we may consider using upgrade here
559 	 * if we want to call flush from inside a transaction
560 	 */
561 	rw_enter(&wl->wl_rwlock, RW_WRITER);
562 	wl->wl_flush(wl->wl_mount, wl->wl_deallocblks, wl->wl_dealloclens,
563 	    wl->wl_dealloccnt);
564 
565 #ifdef WAPBL_DEBUG_PRINT
566 	{
567 		pid_t pid = -1;
568 		lwpid_t lid = -1;
569 		if (curproc)
570 			pid = curproc->p_pid;
571 		if (curlwp)
572 			lid = curlwp->l_lid;
573 #ifdef WAPBL_DEBUG_BUFBYTES
574 		WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
575 		    ("wapbl_discard: thread %d.%d discarding "
576 		    "transaction\n"
577 		    "\tbufcount=%zu bufbytes=%zu bcount=%zu "
578 		    "deallocs=%d inodes=%d\n"
579 		    "\terrcnt = %u, reclaimable=%zu reserved=%zu "
580 		    "unsynced=%zu\n",
581 		    pid, lid, wl->wl_bufcount, wl->wl_bufbytes,
582 		    wl->wl_bcount, wl->wl_dealloccnt,
583 		    wl->wl_inohashcnt, wl->wl_error_count,
584 		    wl->wl_reclaimable_bytes, wl->wl_reserved_bytes,
585 		    wl->wl_unsynced_bufbytes));
586 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
587 			WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
588 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
589 			     "error = %d, unsynced = %zu\n",
590 			     we->we_bufcount, we->we_reclaimable_bytes,
591 			     we->we_error, we->we_unsynced_bufbytes));
592 		}
593 #else /* !WAPBL_DEBUG_BUFBYTES */
594 		WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
595 		    ("wapbl_discard: thread %d.%d discarding transaction\n"
596 		    "\tbufcount=%zu bufbytes=%zu bcount=%zu "
597 		    "deallocs=%d inodes=%d\n"
598 		    "\terrcnt = %u, reclaimable=%zu reserved=%zu\n",
599 		    pid, lid, wl->wl_bufcount, wl->wl_bufbytes,
600 		    wl->wl_bcount, wl->wl_dealloccnt,
601 		    wl->wl_inohashcnt, wl->wl_error_count,
602 		    wl->wl_reclaimable_bytes, wl->wl_reserved_bytes));
603 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
604 			WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
605 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
606 			     "error = %d\n",
607 			     we->we_bufcount, we->we_reclaimable_bytes,
608 			     we->we_error));
609 		}
610 #endif /* !WAPBL_DEBUG_BUFBYTES */
611 	}
612 #endif /* WAPBL_DEBUG_PRINT */
613 
614 	for (i = 0; i <= wl->wl_inohashmask; i++) {
615 		struct wapbl_ino_head *wih;
616 		struct wapbl_ino *wi;
617 
618 		wih = &wl->wl_inohash[i];
619 		while ((wi = LIST_FIRST(wih)) != NULL) {
620 			LIST_REMOVE(wi, wi_hash);
621 			pool_put(&wapbl_ino_pool, wi);
622 			KASSERT(wl->wl_inohashcnt > 0);
623 			wl->wl_inohashcnt--;
624 		}
625 	}
626 
627 	/*
628 	 * clean buffer list
629 	 */
630 	mutex_enter(&bufcache_lock);
631 	mutex_enter(&wl->wl_mtx);
632 	while ((bp = LIST_FIRST(&wl->wl_bufs)) != NULL) {
633 		if (bbusy(bp, 0, 0, &wl->wl_mtx) == 0) {
634 			/*
635 			 * The buffer will be unlocked and
636 			 * removed from the transaction in brelse
637 			 */
638 			mutex_exit(&wl->wl_mtx);
639 			brelsel(bp, 0);
640 			mutex_enter(&wl->wl_mtx);
641 		}
642 	}
643 	mutex_exit(&wl->wl_mtx);
644 	mutex_exit(&bufcache_lock);
645 
646 	/*
647 	 * Remove references to this wl from wl_entries, free any which
648 	 * no longer have buffers, others will be freed in wapbl_biodone
649 	 * when they no longer have any buffers.
650 	 */
651 	while ((we = SIMPLEQ_FIRST(&wl->wl_entries)) != NULL) {
652 		SIMPLEQ_REMOVE_HEAD(&wl->wl_entries, we_entries);
653 		/* XXX should we be accumulating wl_error_count
654 		 * and increasing reclaimable bytes ? */
655 		we->we_wapbl = NULL;
656 		if (we->we_bufcount == 0) {
657 #ifdef WAPBL_DEBUG_BUFBYTES
658 			KASSERT(we->we_unsynced_bufbytes == 0);
659 #endif
660 			pool_put(&wapbl_entry_pool, we);
661 		}
662 	}
663 
664 	/* Discard list of deallocs */
665 	wl->wl_dealloccnt = 0;
666 	/* XXX should we clear wl_reserved_bytes? */
667 
668 	KASSERT(wl->wl_bufbytes == 0);
669 	KASSERT(wl->wl_bcount == 0);
670 	KASSERT(wl->wl_bufcount == 0);
671 	KASSERT(LIST_EMPTY(&wl->wl_bufs));
672 	KASSERT(SIMPLEQ_EMPTY(&wl->wl_entries));
673 	KASSERT(wl->wl_inohashcnt == 0);
674 
675 	rw_exit(&wl->wl_rwlock);
676 }
677 
678 int
679 wapbl_stop(struct wapbl *wl, int force)
680 {
681 	int error;
682 
683 	WAPBL_PRINTF(WAPBL_PRINT_OPEN, ("wapbl_stop called\n"));
684 	error = wapbl_flush(wl, 1);
685 	if (error) {
686 		if (force)
687 			wapbl_discard(wl);
688 		else
689 			return error;
690 	}
691 
692 	/* Unlinked inodes persist after a flush */
693 	if (wl->wl_inohashcnt) {
694 		if (force) {
695 			wapbl_discard(wl);
696 		} else {
697 			return EBUSY;
698 		}
699 	}
700 
701 	KASSERT(wl->wl_bufbytes == 0);
702 	KASSERT(wl->wl_bcount == 0);
703 	KASSERT(wl->wl_bufcount == 0);
704 	KASSERT(LIST_EMPTY(&wl->wl_bufs));
705 	KASSERT(wl->wl_dealloccnt == 0);
706 	KASSERT(SIMPLEQ_EMPTY(&wl->wl_entries));
707 	KASSERT(wl->wl_inohashcnt == 0);
708 
709 	wapbl_free(wl->wl_wc_scratch, wl->wl_wc_header->wc_len);
710 	wapbl_free(wl->wl_wc_header, wl->wl_wc_header->wc_len);
711 	wapbl_free(wl->wl_deallocblks,
712 	    sizeof(*wl->wl_deallocblks) * wl->wl_dealloclim);
713 	wapbl_free(wl->wl_dealloclens,
714 	    sizeof(*wl->wl_dealloclens) * wl->wl_dealloclim);
715 	wapbl_free(wl->wl_buffer, MAXPHYS);
716 	wapbl_inodetrk_free(wl);
717 
718 	cv_destroy(&wl->wl_reclaimable_cv);
719 	mutex_destroy(&wl->wl_mtx);
720 	rw_destroy(&wl->wl_rwlock);
721 	wapbl_free(wl, sizeof(*wl));
722 
723 	return 0;
724 }
725 
726 static int
727 wapbl_doio(void *data, size_t len, struct vnode *devvp, daddr_t pbn, int flags)
728 {
729 	struct pstats *pstats = curlwp->l_proc->p_stats;
730 	struct buf *bp;
731 	int error;
732 
733 	KASSERT((flags & ~(B_WRITE | B_READ)) == 0);
734 	KASSERT(devvp->v_type == VBLK);
735 
736 	if ((flags & (B_WRITE | B_READ)) == B_WRITE) {
737 		mutex_enter(devvp->v_interlock);
738 		devvp->v_numoutput++;
739 		mutex_exit(devvp->v_interlock);
740 		pstats->p_ru.ru_oublock++;
741 	} else {
742 		pstats->p_ru.ru_inblock++;
743 	}
744 
745 	bp = getiobuf(devvp, true);
746 	bp->b_flags = flags;
747 	bp->b_cflags = BC_BUSY; /* silly & dubious */
748 	bp->b_dev = devvp->v_rdev;
749 	bp->b_data = data;
750 	bp->b_bufsize = bp->b_resid = bp->b_bcount = len;
751 	bp->b_blkno = pbn;
752 	BIO_SETPRIO(bp, BPRIO_TIMECRITICAL);
753 
754 	WAPBL_PRINTF(WAPBL_PRINT_IO,
755 	    ("wapbl_doio: %s %d bytes at block %"PRId64" on dev 0x%"PRIx64"\n",
756 	    BUF_ISWRITE(bp) ? "write" : "read", bp->b_bcount,
757 	    bp->b_blkno, bp->b_dev));
758 
759 	VOP_STRATEGY(devvp, bp);
760 
761 	error = biowait(bp);
762 	putiobuf(bp);
763 
764 	if (error) {
765 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
766 		    ("wapbl_doio: %s %zu bytes at block %" PRId64
767 		    " on dev 0x%"PRIx64" failed with error %d\n",
768 		    (((flags & (B_WRITE | B_READ)) == B_WRITE) ?
769 		     "write" : "read"),
770 		    len, pbn, devvp->v_rdev, error));
771 	}
772 
773 	return error;
774 }
775 
776 int
777 wapbl_write(void *data, size_t len, struct vnode *devvp, daddr_t pbn)
778 {
779 
780 	return wapbl_doio(data, len, devvp, pbn, B_WRITE);
781 }
782 
783 int
784 wapbl_read(void *data, size_t len, struct vnode *devvp, daddr_t pbn)
785 {
786 
787 	return wapbl_doio(data, len, devvp, pbn, B_READ);
788 }
789 
790 /*
791  * Flush buffered data if any.
792  */
793 static int
794 wapbl_buffered_flush(struct wapbl *wl)
795 {
796 	int error;
797 
798 	if (wl->wl_buffer_used == 0)
799 		return 0;
800 
801 	error = wapbl_doio(wl->wl_buffer, wl->wl_buffer_used,
802 	    wl->wl_devvp, wl->wl_buffer_dblk, B_WRITE);
803 	wl->wl_buffer_used = 0;
804 
805 	return error;
806 }
807 
808 /*
809  * Write data to the log.
810  * Try to coalesce writes and emit MAXPHYS aligned blocks.
811  */
812 static int
813 wapbl_buffered_write(void *data, size_t len, struct wapbl *wl, daddr_t pbn)
814 {
815 	int error;
816 	size_t resid;
817 
818 	/*
819 	 * If not adjacent to buffered data flush first.  Disk block
820 	 * address is always valid for non-empty buffer.
821 	 */
822 	if (wl->wl_buffer_used > 0 &&
823 	    pbn != wl->wl_buffer_dblk + btodb(wl->wl_buffer_used)) {
824 		error = wapbl_buffered_flush(wl);
825 		if (error)
826 			return error;
827 	}
828 	/*
829 	 * If this write goes to an empty buffer we have to
830 	 * save the disk block address first.
831 	 */
832 	if (wl->wl_buffer_used == 0)
833 		wl->wl_buffer_dblk = pbn;
834 	/*
835 	 * Remaining space so this buffer ends on a MAXPHYS boundary.
836 	 *
837 	 * Cannot become less or equal zero as the buffer would have been
838 	 * flushed on the last call then.
839 	 */
840 	resid = MAXPHYS - dbtob(wl->wl_buffer_dblk % btodb(MAXPHYS)) -
841 	    wl->wl_buffer_used;
842 	KASSERT(resid > 0);
843 	KASSERT(dbtob(btodb(resid)) == resid);
844 	if (len >= resid) {
845 		memcpy(wl->wl_buffer + wl->wl_buffer_used, data, resid);
846 		wl->wl_buffer_used += resid;
847 		error = wapbl_doio(wl->wl_buffer, wl->wl_buffer_used,
848 		    wl->wl_devvp, wl->wl_buffer_dblk, B_WRITE);
849 		data = (uint8_t *)data + resid;
850 		len -= resid;
851 		wl->wl_buffer_dblk = pbn + btodb(resid);
852 		wl->wl_buffer_used = 0;
853 		if (error)
854 			return error;
855 	}
856 	KASSERT(len < MAXPHYS);
857 	if (len > 0) {
858 		memcpy(wl->wl_buffer + wl->wl_buffer_used, data, len);
859 		wl->wl_buffer_used += len;
860 	}
861 
862 	return 0;
863 }
864 
865 /*
866  * Off is byte offset returns new offset for next write
867  * handles log wraparound
868  */
869 static int
870 wapbl_circ_write(struct wapbl *wl, void *data, size_t len, off_t *offp)
871 {
872 	size_t slen;
873 	off_t off = *offp;
874 	int error;
875 	daddr_t pbn;
876 
877 	KDASSERT(((len >> wl->wl_log_dev_bshift) <<
878 	    wl->wl_log_dev_bshift) == len);
879 
880 	if (off < wl->wl_circ_off)
881 		off = wl->wl_circ_off;
882 	slen = wl->wl_circ_off + wl->wl_circ_size - off;
883 	if (slen < len) {
884 		pbn = wl->wl_logpbn + (off >> wl->wl_log_dev_bshift);
885 #ifdef _KERNEL
886 		pbn = btodb(pbn << wl->wl_log_dev_bshift);
887 #endif
888 		error = wapbl_buffered_write(data, slen, wl, pbn);
889 		if (error)
890 			return error;
891 		data = (uint8_t *)data + slen;
892 		len -= slen;
893 		off = wl->wl_circ_off;
894 	}
895 	pbn = wl->wl_logpbn + (off >> wl->wl_log_dev_bshift);
896 #ifdef _KERNEL
897 	pbn = btodb(pbn << wl->wl_log_dev_bshift);
898 #endif
899 	error = wapbl_buffered_write(data, len, wl, pbn);
900 	if (error)
901 		return error;
902 	off += len;
903 	if (off >= wl->wl_circ_off + wl->wl_circ_size)
904 		off = wl->wl_circ_off;
905 	*offp = off;
906 	return 0;
907 }
908 
909 /****************************************************************/
910 
911 int
912 wapbl_begin(struct wapbl *wl, const char *file, int line)
913 {
914 	int doflush;
915 	unsigned lockcount;
916 
917 	KDASSERT(wl);
918 
919 	/*
920 	 * XXX this needs to be made much more sophisticated.
921 	 * perhaps each wapbl_begin could reserve a specified
922 	 * number of buffers and bytes.
923 	 */
924 	mutex_enter(&wl->wl_mtx);
925 	lockcount = wl->wl_lock_count;
926 	doflush = ((wl->wl_bufbytes + (lockcount * MAXPHYS)) >
927 		   wl->wl_bufbytes_max / 2) ||
928 		  ((wl->wl_bufcount + (lockcount * 10)) >
929 		   wl->wl_bufcount_max / 2) ||
930 		  (wapbl_transaction_len(wl) > wl->wl_circ_size / 2) ||
931 		  (wl->wl_dealloccnt >= (wl->wl_dealloclim / 2));
932 	mutex_exit(&wl->wl_mtx);
933 
934 	if (doflush) {
935 		WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
936 		    ("force flush lockcnt=%d bufbytes=%zu "
937 		    "(max=%zu) bufcount=%zu (max=%zu) "
938 		    "dealloccnt %d (lim=%d)\n",
939 		    lockcount, wl->wl_bufbytes,
940 		    wl->wl_bufbytes_max, wl->wl_bufcount,
941 		    wl->wl_bufcount_max,
942 		    wl->wl_dealloccnt, wl->wl_dealloclim));
943 	}
944 
945 	if (doflush) {
946 		int error = wapbl_flush(wl, 0);
947 		if (error)
948 			return error;
949 	}
950 
951 	rw_enter(&wl->wl_rwlock, RW_READER);
952 	mutex_enter(&wl->wl_mtx);
953 	wl->wl_lock_count++;
954 	mutex_exit(&wl->wl_mtx);
955 
956 #if defined(WAPBL_DEBUG_PRINT)
957 	WAPBL_PRINTF(WAPBL_PRINT_TRANSACTION,
958 	    ("wapbl_begin thread %d.%d with bufcount=%zu "
959 	    "bufbytes=%zu bcount=%zu at %s:%d\n",
960 	    curproc->p_pid, curlwp->l_lid, wl->wl_bufcount,
961 	    wl->wl_bufbytes, wl->wl_bcount, file, line));
962 #endif
963 
964 	return 0;
965 }
966 
967 void
968 wapbl_end(struct wapbl *wl)
969 {
970 
971 #if defined(WAPBL_DEBUG_PRINT)
972 	WAPBL_PRINTF(WAPBL_PRINT_TRANSACTION,
973 	     ("wapbl_end thread %d.%d with bufcount=%zu "
974 	      "bufbytes=%zu bcount=%zu\n",
975 	      curproc->p_pid, curlwp->l_lid, wl->wl_bufcount,
976 	      wl->wl_bufbytes, wl->wl_bcount));
977 #endif
978 
979 #ifdef DIAGNOSTIC
980 	size_t flushsize = wapbl_transaction_len(wl);
981 	if (flushsize > (wl->wl_circ_size - wl->wl_reserved_bytes)) {
982 		/*
983 		 * XXX this could be handled more gracefully, perhaps place
984 		 * only a partial transaction in the log and allow the
985 		 * remaining to flush without the protection of the journal.
986 		 */
987 		panic("wapbl_end: current transaction too big to flush\n");
988 	}
989 #endif
990 
991 	mutex_enter(&wl->wl_mtx);
992 	KASSERT(wl->wl_lock_count > 0);
993 	wl->wl_lock_count--;
994 	mutex_exit(&wl->wl_mtx);
995 
996 	rw_exit(&wl->wl_rwlock);
997 }
998 
999 void
1000 wapbl_add_buf(struct wapbl *wl, struct buf * bp)
1001 {
1002 
1003 	KASSERT(bp->b_cflags & BC_BUSY);
1004 	KASSERT(bp->b_vp);
1005 
1006 	wapbl_jlock_assert(wl);
1007 
1008 #if 0
1009 	/*
1010 	 * XXX this might be an issue for swapfiles.
1011 	 * see uvm_swap.c:1702
1012 	 *
1013 	 * XXX2 why require it then?  leap of semantics?
1014 	 */
1015 	KASSERT((bp->b_cflags & BC_NOCACHE) == 0);
1016 #endif
1017 
1018 	mutex_enter(&wl->wl_mtx);
1019 	if (bp->b_flags & B_LOCKED) {
1020 		LIST_REMOVE(bp, b_wapbllist);
1021 		WAPBL_PRINTF(WAPBL_PRINT_BUFFER2,
1022 		   ("wapbl_add_buf thread %d.%d re-adding buf %p "
1023 		    "with %d bytes %d bcount\n",
1024 		    curproc->p_pid, curlwp->l_lid, bp, bp->b_bufsize,
1025 		    bp->b_bcount));
1026 	} else {
1027 		/* unlocked by dirty buffers shouldn't exist */
1028 		KASSERT(!(bp->b_oflags & BO_DELWRI));
1029 		wl->wl_bufbytes += bp->b_bufsize;
1030 		wl->wl_bcount += bp->b_bcount;
1031 		wl->wl_bufcount++;
1032 		WAPBL_PRINTF(WAPBL_PRINT_BUFFER,
1033 		   ("wapbl_add_buf thread %d.%d adding buf %p "
1034 		    "with %d bytes %d bcount\n",
1035 		    curproc->p_pid, curlwp->l_lid, bp, bp->b_bufsize,
1036 		    bp->b_bcount));
1037 	}
1038 	LIST_INSERT_HEAD(&wl->wl_bufs, bp, b_wapbllist);
1039 	mutex_exit(&wl->wl_mtx);
1040 
1041 	bp->b_flags |= B_LOCKED;
1042 }
1043 
1044 static void
1045 wapbl_remove_buf_locked(struct wapbl * wl, struct buf *bp)
1046 {
1047 
1048 	KASSERT(mutex_owned(&wl->wl_mtx));
1049 	KASSERT(bp->b_cflags & BC_BUSY);
1050 	wapbl_jlock_assert(wl);
1051 
1052 #if 0
1053 	/*
1054 	 * XXX this might be an issue for swapfiles.
1055 	 * see uvm_swap.c:1725
1056 	 *
1057 	 * XXXdeux: see above
1058 	 */
1059 	KASSERT((bp->b_flags & BC_NOCACHE) == 0);
1060 #endif
1061 	KASSERT(bp->b_flags & B_LOCKED);
1062 
1063 	WAPBL_PRINTF(WAPBL_PRINT_BUFFER,
1064 	   ("wapbl_remove_buf thread %d.%d removing buf %p with "
1065 	    "%d bytes %d bcount\n",
1066 	    curproc->p_pid, curlwp->l_lid, bp, bp->b_bufsize, bp->b_bcount));
1067 
1068 	KASSERT(wl->wl_bufbytes >= bp->b_bufsize);
1069 	wl->wl_bufbytes -= bp->b_bufsize;
1070 	KASSERT(wl->wl_bcount >= bp->b_bcount);
1071 	wl->wl_bcount -= bp->b_bcount;
1072 	KASSERT(wl->wl_bufcount > 0);
1073 	wl->wl_bufcount--;
1074 	KASSERT((wl->wl_bufcount == 0) == (wl->wl_bufbytes == 0));
1075 	KASSERT((wl->wl_bufcount == 0) == (wl->wl_bcount == 0));
1076 	LIST_REMOVE(bp, b_wapbllist);
1077 
1078 	bp->b_flags &= ~B_LOCKED;
1079 }
1080 
1081 /* called from brelsel() in vfs_bio among other places */
1082 void
1083 wapbl_remove_buf(struct wapbl * wl, struct buf *bp)
1084 {
1085 
1086 	mutex_enter(&wl->wl_mtx);
1087 	wapbl_remove_buf_locked(wl, bp);
1088 	mutex_exit(&wl->wl_mtx);
1089 }
1090 
1091 void
1092 wapbl_resize_buf(struct wapbl *wl, struct buf *bp, long oldsz, long oldcnt)
1093 {
1094 
1095 	KASSERT(bp->b_cflags & BC_BUSY);
1096 
1097 	/*
1098 	 * XXX: why does this depend on B_LOCKED?  otherwise the buf
1099 	 * is not for a transaction?  if so, why is this called in the
1100 	 * first place?
1101 	 */
1102 	if (bp->b_flags & B_LOCKED) {
1103 		mutex_enter(&wl->wl_mtx);
1104 		wl->wl_bufbytes += bp->b_bufsize - oldsz;
1105 		wl->wl_bcount += bp->b_bcount - oldcnt;
1106 		mutex_exit(&wl->wl_mtx);
1107 	}
1108 }
1109 
1110 #endif /* _KERNEL */
1111 
1112 /****************************************************************/
1113 /* Some utility inlines */
1114 
1115 static inline size_t
1116 wapbl_space_used(size_t avail, off_t head, off_t tail)
1117 {
1118 
1119 	if (tail == 0) {
1120 		KASSERT(head == 0);
1121 		return 0;
1122 	}
1123 	return ((head + (avail - 1) - tail) % avail) + 1;
1124 }
1125 
1126 #ifdef _KERNEL
1127 /* This is used to advance the pointer at old to new value at old+delta */
1128 static inline off_t
1129 wapbl_advance(size_t size, size_t off, off_t oldoff, size_t delta)
1130 {
1131 	off_t newoff;
1132 
1133 	/* Define acceptable ranges for inputs. */
1134 	KASSERT(delta <= (size_t)size);
1135 	KASSERT((oldoff == 0) || ((size_t)oldoff >= off));
1136 	KASSERT(oldoff < (off_t)(size + off));
1137 
1138 	if ((oldoff == 0) && (delta != 0))
1139 		newoff = off + delta;
1140 	else if ((oldoff + delta) < (size + off))
1141 		newoff = oldoff + delta;
1142 	else
1143 		newoff = (oldoff + delta) - size;
1144 
1145 	/* Note some interesting axioms */
1146 	KASSERT((delta != 0) || (newoff == oldoff));
1147 	KASSERT((delta == 0) || (newoff != 0));
1148 	KASSERT((delta != (size)) || (newoff == oldoff));
1149 
1150 	/* Define acceptable ranges for output. */
1151 	KASSERT((newoff == 0) || ((size_t)newoff >= off));
1152 	KASSERT((size_t)newoff < (size + off));
1153 	return newoff;
1154 }
1155 
1156 static inline size_t
1157 wapbl_space_free(size_t avail, off_t head, off_t tail)
1158 {
1159 
1160 	return avail - wapbl_space_used(avail, head, tail);
1161 }
1162 
1163 static inline void
1164 wapbl_advance_head(size_t size, size_t off, size_t delta, off_t *headp,
1165 		   off_t *tailp)
1166 {
1167 	off_t head = *headp;
1168 	off_t tail = *tailp;
1169 
1170 	KASSERT(delta <= wapbl_space_free(size, head, tail));
1171 	head = wapbl_advance(size, off, head, delta);
1172 	if ((tail == 0) && (head != 0))
1173 		tail = off;
1174 	*headp = head;
1175 	*tailp = tail;
1176 }
1177 
1178 static inline void
1179 wapbl_advance_tail(size_t size, size_t off, size_t delta, off_t *headp,
1180 		   off_t *tailp)
1181 {
1182 	off_t head = *headp;
1183 	off_t tail = *tailp;
1184 
1185 	KASSERT(delta <= wapbl_space_used(size, head, tail));
1186 	tail = wapbl_advance(size, off, tail, delta);
1187 	if (head == tail) {
1188 		head = tail = 0;
1189 	}
1190 	*headp = head;
1191 	*tailp = tail;
1192 }
1193 
1194 
1195 /****************************************************************/
1196 
1197 /*
1198  * Remove transactions whose buffers are completely flushed to disk.
1199  * Will block until at least minfree space is available.
1200  * only intended to be called from inside wapbl_flush and therefore
1201  * does not protect against commit races with itself or with flush.
1202  */
1203 static int
1204 wapbl_truncate(struct wapbl *wl, size_t minfree, int waitonly)
1205 {
1206 	size_t delta;
1207 	size_t avail;
1208 	off_t head;
1209 	off_t tail;
1210 	int error = 0;
1211 
1212 	KASSERT(minfree <= (wl->wl_circ_size - wl->wl_reserved_bytes));
1213 	KASSERT(rw_write_held(&wl->wl_rwlock));
1214 
1215 	mutex_enter(&wl->wl_mtx);
1216 
1217 	/*
1218 	 * First check to see if we have to do a commit
1219 	 * at all.
1220 	 */
1221 	avail = wapbl_space_free(wl->wl_circ_size, wl->wl_head, wl->wl_tail);
1222 	if (minfree < avail) {
1223 		mutex_exit(&wl->wl_mtx);
1224 		return 0;
1225 	}
1226 	minfree -= avail;
1227 	while ((wl->wl_error_count == 0) &&
1228 	    (wl->wl_reclaimable_bytes < minfree)) {
1229         	WAPBL_PRINTF(WAPBL_PRINT_TRUNCATE,
1230                    ("wapbl_truncate: sleeping on %p wl=%p bytes=%zd "
1231 		    "minfree=%zd\n",
1232                     &wl->wl_reclaimable_bytes, wl, wl->wl_reclaimable_bytes,
1233 		    minfree));
1234 
1235 		cv_wait(&wl->wl_reclaimable_cv, &wl->wl_mtx);
1236 	}
1237 	if (wl->wl_reclaimable_bytes < minfree) {
1238 		KASSERT(wl->wl_error_count);
1239 		/* XXX maybe get actual error from buffer instead someday? */
1240 		error = EIO;
1241 	}
1242 	head = wl->wl_head;
1243 	tail = wl->wl_tail;
1244 	delta = wl->wl_reclaimable_bytes;
1245 
1246 	/* If all of of the entries are flushed, then be sure to keep
1247 	 * the reserved bytes reserved.  Watch out for discarded transactions,
1248 	 * which could leave more bytes reserved than are reclaimable.
1249 	 */
1250 	if (SIMPLEQ_EMPTY(&wl->wl_entries) &&
1251 	    (delta >= wl->wl_reserved_bytes)) {
1252 		delta -= wl->wl_reserved_bytes;
1253 	}
1254 	wapbl_advance_tail(wl->wl_circ_size, wl->wl_circ_off, delta, &head,
1255 			   &tail);
1256 	KDASSERT(wl->wl_reserved_bytes <=
1257 		wapbl_space_used(wl->wl_circ_size, head, tail));
1258 	mutex_exit(&wl->wl_mtx);
1259 
1260 	if (error)
1261 		return error;
1262 
1263 	if (waitonly)
1264 		return 0;
1265 
1266 	/*
1267 	 * This is where head, tail and delta are unprotected
1268 	 * from races against itself or flush.  This is ok since
1269 	 * we only call this routine from inside flush itself.
1270 	 *
1271 	 * XXX: how can it race against itself when accessed only
1272 	 * from behind the write-locked rwlock?
1273 	 */
1274 	error = wapbl_write_commit(wl, head, tail);
1275 	if (error)
1276 		return error;
1277 
1278 	wl->wl_head = head;
1279 	wl->wl_tail = tail;
1280 
1281 	mutex_enter(&wl->wl_mtx);
1282 	KASSERT(wl->wl_reclaimable_bytes >= delta);
1283 	wl->wl_reclaimable_bytes -= delta;
1284 	mutex_exit(&wl->wl_mtx);
1285 	WAPBL_PRINTF(WAPBL_PRINT_TRUNCATE,
1286 	    ("wapbl_truncate thread %d.%d truncating %zu bytes\n",
1287 	    curproc->p_pid, curlwp->l_lid, delta));
1288 
1289 	return 0;
1290 }
1291 
1292 /****************************************************************/
1293 
1294 void
1295 wapbl_biodone(struct buf *bp)
1296 {
1297 	struct wapbl_entry *we = bp->b_private;
1298 	struct wapbl *wl = we->we_wapbl;
1299 #ifdef WAPBL_DEBUG_BUFBYTES
1300 	const int bufsize = bp->b_bufsize;
1301 #endif
1302 
1303 	/*
1304 	 * Handle possible flushing of buffers after log has been
1305 	 * decomissioned.
1306 	 */
1307 	if (!wl) {
1308 		KASSERT(we->we_bufcount > 0);
1309 		we->we_bufcount--;
1310 #ifdef WAPBL_DEBUG_BUFBYTES
1311 		KASSERT(we->we_unsynced_bufbytes >= bufsize);
1312 		we->we_unsynced_bufbytes -= bufsize;
1313 #endif
1314 
1315 		if (we->we_bufcount == 0) {
1316 #ifdef WAPBL_DEBUG_BUFBYTES
1317 			KASSERT(we->we_unsynced_bufbytes == 0);
1318 #endif
1319 			pool_put(&wapbl_entry_pool, we);
1320 		}
1321 
1322 		brelse(bp, 0);
1323 		return;
1324 	}
1325 
1326 #ifdef ohbother
1327 	KDASSERT(bp->b_oflags & BO_DONE);
1328 	KDASSERT(!(bp->b_oflags & BO_DELWRI));
1329 	KDASSERT(bp->b_flags & B_ASYNC);
1330 	KDASSERT(bp->b_cflags & BC_BUSY);
1331 	KDASSERT(!(bp->b_flags & B_LOCKED));
1332 	KDASSERT(!(bp->b_flags & B_READ));
1333 	KDASSERT(!(bp->b_cflags & BC_INVAL));
1334 	KDASSERT(!(bp->b_cflags & BC_NOCACHE));
1335 #endif
1336 
1337 	if (bp->b_error) {
1338 #ifdef notyet /* Can't currently handle possible dirty buffer reuse */
1339 		/*
1340 		 * XXXpooka: interfaces not fully updated
1341 		 * Note: this was not enabled in the original patch
1342 		 * against netbsd4 either.  I don't know if comment
1343 		 * above is true or not.
1344 		 */
1345 
1346 		/*
1347 		 * If an error occurs, report the error and leave the
1348 		 * buffer as a delayed write on the LRU queue.
1349 		 * restarting the write would likely result in
1350 		 * an error spinloop, so let it be done harmlessly
1351 		 * by the syncer.
1352 		 */
1353 		bp->b_flags &= ~(B_DONE);
1354 		simple_unlock(&bp->b_interlock);
1355 
1356 		if (we->we_error == 0) {
1357 			mutex_enter(&wl->wl_mtx);
1358 			wl->wl_error_count++;
1359 			mutex_exit(&wl->wl_mtx);
1360 			cv_broadcast(&wl->wl_reclaimable_cv);
1361 		}
1362 		we->we_error = bp->b_error;
1363 		bp->b_error = 0;
1364 		brelse(bp);
1365 		return;
1366 #else
1367 		/* For now, just mark the log permanently errored out */
1368 
1369 		mutex_enter(&wl->wl_mtx);
1370 		if (wl->wl_error_count == 0) {
1371 			wl->wl_error_count++;
1372 			cv_broadcast(&wl->wl_reclaimable_cv);
1373 		}
1374 		mutex_exit(&wl->wl_mtx);
1375 #endif
1376 	}
1377 
1378 	/*
1379 	 * Release the buffer here. wapbl_flush() may wait for the
1380 	 * log to become empty and we better unbusy the buffer before
1381 	 * wapbl_flush() returns.
1382 	 */
1383 	brelse(bp, 0);
1384 
1385 	mutex_enter(&wl->wl_mtx);
1386 
1387 	KASSERT(we->we_bufcount > 0);
1388 	we->we_bufcount--;
1389 #ifdef WAPBL_DEBUG_BUFBYTES
1390 	KASSERT(we->we_unsynced_bufbytes >= bufsize);
1391 	we->we_unsynced_bufbytes -= bufsize;
1392 	KASSERT(wl->wl_unsynced_bufbytes >= bufsize);
1393 	wl->wl_unsynced_bufbytes -= bufsize;
1394 #endif
1395 
1396 	/*
1397 	 * If the current transaction can be reclaimed, start
1398 	 * at the beginning and reclaim any consecutive reclaimable
1399 	 * transactions.  If we successfully reclaim anything,
1400 	 * then wakeup anyone waiting for the reclaim.
1401 	 */
1402 	if (we->we_bufcount == 0) {
1403 		size_t delta = 0;
1404 		int errcnt = 0;
1405 #ifdef WAPBL_DEBUG_BUFBYTES
1406 		KDASSERT(we->we_unsynced_bufbytes == 0);
1407 #endif
1408 		/*
1409 		 * clear any posted error, since the buffer it came from
1410 		 * has successfully flushed by now
1411 		 */
1412 		while ((we = SIMPLEQ_FIRST(&wl->wl_entries)) &&
1413 		       (we->we_bufcount == 0)) {
1414 			delta += we->we_reclaimable_bytes;
1415 			if (we->we_error)
1416 				errcnt++;
1417 			SIMPLEQ_REMOVE_HEAD(&wl->wl_entries, we_entries);
1418 			pool_put(&wapbl_entry_pool, we);
1419 		}
1420 
1421 		if (delta) {
1422 			wl->wl_reclaimable_bytes += delta;
1423 			KASSERT(wl->wl_error_count >= errcnt);
1424 			wl->wl_error_count -= errcnt;
1425 			cv_broadcast(&wl->wl_reclaimable_cv);
1426 		}
1427 	}
1428 
1429 	mutex_exit(&wl->wl_mtx);
1430 }
1431 
1432 /*
1433  * Write transactions to disk + start I/O for contents
1434  */
1435 int
1436 wapbl_flush(struct wapbl *wl, int waitfor)
1437 {
1438 	struct buf *bp;
1439 	struct wapbl_entry *we;
1440 	off_t off;
1441 	off_t head;
1442 	off_t tail;
1443 	size_t delta = 0;
1444 	size_t flushsize;
1445 	size_t reserved;
1446 	int error = 0;
1447 
1448 	/*
1449 	 * Do a quick check to see if a full flush can be skipped
1450 	 * This assumes that the flush callback does not need to be called
1451 	 * unless there are other outstanding bufs.
1452 	 */
1453 	if (!waitfor) {
1454 		size_t nbufs;
1455 		mutex_enter(&wl->wl_mtx);	/* XXX need mutex here to
1456 						   protect the KASSERTS */
1457 		nbufs = wl->wl_bufcount;
1458 		KASSERT((wl->wl_bufcount == 0) == (wl->wl_bufbytes == 0));
1459 		KASSERT((wl->wl_bufcount == 0) == (wl->wl_bcount == 0));
1460 		mutex_exit(&wl->wl_mtx);
1461 		if (nbufs == 0)
1462 			return 0;
1463 	}
1464 
1465 	/*
1466 	 * XXX we may consider using LK_UPGRADE here
1467 	 * if we want to call flush from inside a transaction
1468 	 */
1469 	rw_enter(&wl->wl_rwlock, RW_WRITER);
1470 	wl->wl_flush(wl->wl_mount, wl->wl_deallocblks, wl->wl_dealloclens,
1471 	    wl->wl_dealloccnt);
1472 
1473 	/*
1474 	 * Now that we are fully locked and flushed,
1475 	 * do another check for nothing to do.
1476 	 */
1477 	if (wl->wl_bufcount == 0) {
1478 		goto out;
1479 	}
1480 
1481 #if 0
1482 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
1483 		     ("wapbl_flush thread %d.%d flushing entries with "
1484 		      "bufcount=%zu bufbytes=%zu\n",
1485 		      curproc->p_pid, curlwp->l_lid, wl->wl_bufcount,
1486 		      wl->wl_bufbytes));
1487 #endif
1488 
1489 	/* Calculate amount of space needed to flush */
1490 	flushsize = wapbl_transaction_len(wl);
1491 	if (wapbl_verbose_commit) {
1492 		struct timespec ts;
1493 		getnanotime(&ts);
1494 		printf("%s: %lld.%09ld this transaction = %zu bytes\n",
1495 		    __func__, (long long)ts.tv_sec,
1496 		    (long)ts.tv_nsec, flushsize);
1497 	}
1498 
1499 	if (flushsize > (wl->wl_circ_size - wl->wl_reserved_bytes)) {
1500 		/*
1501 		 * XXX this could be handled more gracefully, perhaps place
1502 		 * only a partial transaction in the log and allow the
1503 		 * remaining to flush without the protection of the journal.
1504 		 */
1505 		panic("wapbl_flush: current transaction too big to flush\n");
1506 	}
1507 
1508 	error = wapbl_truncate(wl, flushsize, 0);
1509 	if (error)
1510 		goto out2;
1511 
1512 	off = wl->wl_head;
1513 	KASSERT((off == 0) || ((off >= wl->wl_circ_off) &&
1514 	                      (off < wl->wl_circ_off + wl->wl_circ_size)));
1515 	error = wapbl_write_blocks(wl, &off);
1516 	if (error)
1517 		goto out2;
1518 	error = wapbl_write_revocations(wl, &off);
1519 	if (error)
1520 		goto out2;
1521 	error = wapbl_write_inodes(wl, &off);
1522 	if (error)
1523 		goto out2;
1524 
1525 	reserved = 0;
1526 	if (wl->wl_inohashcnt)
1527 		reserved = wapbl_transaction_inodes_len(wl);
1528 
1529 	head = wl->wl_head;
1530 	tail = wl->wl_tail;
1531 
1532 	wapbl_advance_head(wl->wl_circ_size, wl->wl_circ_off, flushsize,
1533 	    &head, &tail);
1534 #ifdef WAPBL_DEBUG
1535 	if (head != off) {
1536 		panic("lost head! head=%"PRIdMAX" tail=%" PRIdMAX
1537 		      " off=%"PRIdMAX" flush=%zu\n",
1538 		      (intmax_t)head, (intmax_t)tail, (intmax_t)off,
1539 		      flushsize);
1540 	}
1541 #else
1542 	KASSERT(head == off);
1543 #endif
1544 
1545 	/* Opportunistically move the tail forward if we can */
1546 	if (!wapbl_lazy_truncate) {
1547 		mutex_enter(&wl->wl_mtx);
1548 		delta = wl->wl_reclaimable_bytes;
1549 		mutex_exit(&wl->wl_mtx);
1550 		wapbl_advance_tail(wl->wl_circ_size, wl->wl_circ_off, delta,
1551 		    &head, &tail);
1552 	}
1553 
1554 	error = wapbl_write_commit(wl, head, tail);
1555 	if (error)
1556 		goto out2;
1557 
1558 	we = pool_get(&wapbl_entry_pool, PR_WAITOK);
1559 
1560 #ifdef WAPBL_DEBUG_BUFBYTES
1561 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
1562 		("wapbl_flush: thread %d.%d head+=%zu tail+=%zu used=%zu"
1563 		 " unsynced=%zu"
1564 		 "\n\tbufcount=%zu bufbytes=%zu bcount=%zu deallocs=%d "
1565 		 "inodes=%d\n",
1566 		 curproc->p_pid, curlwp->l_lid, flushsize, delta,
1567 		 wapbl_space_used(wl->wl_circ_size, head, tail),
1568 		 wl->wl_unsynced_bufbytes, wl->wl_bufcount,
1569 		 wl->wl_bufbytes, wl->wl_bcount, wl->wl_dealloccnt,
1570 		 wl->wl_inohashcnt));
1571 #else
1572 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
1573 		("wapbl_flush: thread %d.%d head+=%zu tail+=%zu used=%zu"
1574 		 "\n\tbufcount=%zu bufbytes=%zu bcount=%zu deallocs=%d "
1575 		 "inodes=%d\n",
1576 		 curproc->p_pid, curlwp->l_lid, flushsize, delta,
1577 		 wapbl_space_used(wl->wl_circ_size, head, tail),
1578 		 wl->wl_bufcount, wl->wl_bufbytes, wl->wl_bcount,
1579 		 wl->wl_dealloccnt, wl->wl_inohashcnt));
1580 #endif
1581 
1582 
1583 	mutex_enter(&bufcache_lock);
1584 	mutex_enter(&wl->wl_mtx);
1585 
1586 	wl->wl_reserved_bytes = reserved;
1587 	wl->wl_head = head;
1588 	wl->wl_tail = tail;
1589 	KASSERT(wl->wl_reclaimable_bytes >= delta);
1590 	wl->wl_reclaimable_bytes -= delta;
1591 	wl->wl_dealloccnt = 0;
1592 #ifdef WAPBL_DEBUG_BUFBYTES
1593 	wl->wl_unsynced_bufbytes += wl->wl_bufbytes;
1594 #endif
1595 
1596 	we->we_wapbl = wl;
1597 	we->we_bufcount = wl->wl_bufcount;
1598 #ifdef WAPBL_DEBUG_BUFBYTES
1599 	we->we_unsynced_bufbytes = wl->wl_bufbytes;
1600 #endif
1601 	we->we_reclaimable_bytes = flushsize;
1602 	we->we_error = 0;
1603 	SIMPLEQ_INSERT_TAIL(&wl->wl_entries, we, we_entries);
1604 
1605 	/*
1606 	 * this flushes bufs in reverse order than they were queued
1607 	 * it shouldn't matter, but if we care we could use TAILQ instead.
1608 	 * XXX Note they will get put on the lru queue when they flush
1609 	 * so we might actually want to change this to preserve order.
1610 	 */
1611 	while ((bp = LIST_FIRST(&wl->wl_bufs)) != NULL) {
1612 		if (bbusy(bp, 0, 0, &wl->wl_mtx)) {
1613 			continue;
1614 		}
1615 		bp->b_iodone = wapbl_biodone;
1616 		bp->b_private = we;
1617 		bremfree(bp);
1618 		wapbl_remove_buf_locked(wl, bp);
1619 		mutex_exit(&wl->wl_mtx);
1620 		mutex_exit(&bufcache_lock);
1621 		bawrite(bp);
1622 		mutex_enter(&bufcache_lock);
1623 		mutex_enter(&wl->wl_mtx);
1624 	}
1625 	mutex_exit(&wl->wl_mtx);
1626 	mutex_exit(&bufcache_lock);
1627 
1628 #if 0
1629 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
1630 		     ("wapbl_flush thread %d.%d done flushing entries...\n",
1631 		     curproc->p_pid, curlwp->l_lid));
1632 #endif
1633 
1634  out:
1635 
1636 	/*
1637 	 * If the waitfor flag is set, don't return until everything is
1638 	 * fully flushed and the on disk log is empty.
1639 	 */
1640 	if (waitfor) {
1641 		error = wapbl_truncate(wl, wl->wl_circ_size -
1642 			wl->wl_reserved_bytes, wapbl_lazy_truncate);
1643 	}
1644 
1645  out2:
1646 	if (error) {
1647 		wl->wl_flush_abort(wl->wl_mount, wl->wl_deallocblks,
1648 		    wl->wl_dealloclens, wl->wl_dealloccnt);
1649 	}
1650 
1651 #ifdef WAPBL_DEBUG_PRINT
1652 	if (error) {
1653 		pid_t pid = -1;
1654 		lwpid_t lid = -1;
1655 		if (curproc)
1656 			pid = curproc->p_pid;
1657 		if (curlwp)
1658 			lid = curlwp->l_lid;
1659 		mutex_enter(&wl->wl_mtx);
1660 #ifdef WAPBL_DEBUG_BUFBYTES
1661 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
1662 		    ("wapbl_flush: thread %d.%d aborted flush: "
1663 		    "error = %d\n"
1664 		    "\tbufcount=%zu bufbytes=%zu bcount=%zu "
1665 		    "deallocs=%d inodes=%d\n"
1666 		    "\terrcnt = %d, reclaimable=%zu reserved=%zu "
1667 		    "unsynced=%zu\n",
1668 		    pid, lid, error, wl->wl_bufcount,
1669 		    wl->wl_bufbytes, wl->wl_bcount,
1670 		    wl->wl_dealloccnt, wl->wl_inohashcnt,
1671 		    wl->wl_error_count, wl->wl_reclaimable_bytes,
1672 		    wl->wl_reserved_bytes, wl->wl_unsynced_bufbytes));
1673 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
1674 			WAPBL_PRINTF(WAPBL_PRINT_ERROR,
1675 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
1676 			     "error = %d, unsynced = %zu\n",
1677 			     we->we_bufcount, we->we_reclaimable_bytes,
1678 			     we->we_error, we->we_unsynced_bufbytes));
1679 		}
1680 #else
1681 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
1682 		    ("wapbl_flush: thread %d.%d aborted flush: "
1683 		     "error = %d\n"
1684 		     "\tbufcount=%zu bufbytes=%zu bcount=%zu "
1685 		     "deallocs=%d inodes=%d\n"
1686 		     "\terrcnt = %d, reclaimable=%zu reserved=%zu\n",
1687 		     pid, lid, error, wl->wl_bufcount,
1688 		     wl->wl_bufbytes, wl->wl_bcount,
1689 		     wl->wl_dealloccnt, wl->wl_inohashcnt,
1690 		     wl->wl_error_count, wl->wl_reclaimable_bytes,
1691 		     wl->wl_reserved_bytes));
1692 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
1693 			WAPBL_PRINTF(WAPBL_PRINT_ERROR,
1694 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
1695 			     "error = %d\n", we->we_bufcount,
1696 			     we->we_reclaimable_bytes, we->we_error));
1697 		}
1698 #endif
1699 		mutex_exit(&wl->wl_mtx);
1700 	}
1701 #endif
1702 
1703 	rw_exit(&wl->wl_rwlock);
1704 	return error;
1705 }
1706 
1707 /****************************************************************/
1708 
1709 void
1710 wapbl_jlock_assert(struct wapbl *wl)
1711 {
1712 
1713 	KASSERT(rw_lock_held(&wl->wl_rwlock));
1714 }
1715 
1716 void
1717 wapbl_junlock_assert(struct wapbl *wl)
1718 {
1719 
1720 	KASSERT(!rw_write_held(&wl->wl_rwlock));
1721 }
1722 
1723 /****************************************************************/
1724 
1725 /* locks missing */
1726 void
1727 wapbl_print(struct wapbl *wl,
1728 		int full,
1729 		void (*pr)(const char *, ...))
1730 {
1731 	struct buf *bp;
1732 	struct wapbl_entry *we;
1733 	(*pr)("wapbl %p", wl);
1734 	(*pr)("\nlogvp = %p, devvp = %p, logpbn = %"PRId64"\n",
1735 	      wl->wl_logvp, wl->wl_devvp, wl->wl_logpbn);
1736 	(*pr)("circ = %zu, header = %zu, head = %"PRIdMAX" tail = %"PRIdMAX"\n",
1737 	      wl->wl_circ_size, wl->wl_circ_off,
1738 	      (intmax_t)wl->wl_head, (intmax_t)wl->wl_tail);
1739 	(*pr)("fs_dev_bshift = %d, log_dev_bshift = %d\n",
1740 	      wl->wl_log_dev_bshift, wl->wl_fs_dev_bshift);
1741 #ifdef WAPBL_DEBUG_BUFBYTES
1742 	(*pr)("bufcount = %zu, bufbytes = %zu bcount = %zu reclaimable = %zu "
1743 	      "reserved = %zu errcnt = %d unsynced = %zu\n",
1744 	      wl->wl_bufcount, wl->wl_bufbytes, wl->wl_bcount,
1745 	      wl->wl_reclaimable_bytes, wl->wl_reserved_bytes,
1746 				wl->wl_error_count, wl->wl_unsynced_bufbytes);
1747 #else
1748 	(*pr)("bufcount = %zu, bufbytes = %zu bcount = %zu reclaimable = %zu "
1749 	      "reserved = %zu errcnt = %d\n", wl->wl_bufcount, wl->wl_bufbytes,
1750 	      wl->wl_bcount, wl->wl_reclaimable_bytes, wl->wl_reserved_bytes,
1751 				wl->wl_error_count);
1752 #endif
1753 	(*pr)("\tdealloccnt = %d, dealloclim = %d\n",
1754 	      wl->wl_dealloccnt, wl->wl_dealloclim);
1755 	(*pr)("\tinohashcnt = %d, inohashmask = 0x%08x\n",
1756 	      wl->wl_inohashcnt, wl->wl_inohashmask);
1757 	(*pr)("entries:\n");
1758 	SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
1759 #ifdef WAPBL_DEBUG_BUFBYTES
1760 		(*pr)("\tbufcount = %zu, reclaimable = %zu, error = %d, "
1761 		      "unsynced = %zu\n",
1762 		      we->we_bufcount, we->we_reclaimable_bytes,
1763 		      we->we_error, we->we_unsynced_bufbytes);
1764 #else
1765 		(*pr)("\tbufcount = %zu, reclaimable = %zu, error = %d\n",
1766 		      we->we_bufcount, we->we_reclaimable_bytes, we->we_error);
1767 #endif
1768 	}
1769 	if (full) {
1770 		int cnt = 0;
1771 		(*pr)("bufs =");
1772 		LIST_FOREACH(bp, &wl->wl_bufs, b_wapbllist) {
1773 			if (!LIST_NEXT(bp, b_wapbllist)) {
1774 				(*pr)(" %p", bp);
1775 			} else if ((++cnt % 6) == 0) {
1776 				(*pr)(" %p,\n\t", bp);
1777 			} else {
1778 				(*pr)(" %p,", bp);
1779 			}
1780 		}
1781 		(*pr)("\n");
1782 
1783 		(*pr)("dealloced blks = ");
1784 		{
1785 			int i;
1786 			cnt = 0;
1787 			for (i = 0; i < wl->wl_dealloccnt; i++) {
1788 				(*pr)(" %"PRId64":%d,",
1789 				      wl->wl_deallocblks[i],
1790 				      wl->wl_dealloclens[i]);
1791 				if ((++cnt % 4) == 0) {
1792 					(*pr)("\n\t");
1793 				}
1794 			}
1795 		}
1796 		(*pr)("\n");
1797 
1798 		(*pr)("registered inodes = ");
1799 		{
1800 			int i;
1801 			cnt = 0;
1802 			for (i = 0; i <= wl->wl_inohashmask; i++) {
1803 				struct wapbl_ino_head *wih;
1804 				struct wapbl_ino *wi;
1805 
1806 				wih = &wl->wl_inohash[i];
1807 				LIST_FOREACH(wi, wih, wi_hash) {
1808 					if (wi->wi_ino == 0)
1809 						continue;
1810 					(*pr)(" %"PRIu64"/0%06"PRIo32",",
1811 					    wi->wi_ino, wi->wi_mode);
1812 					if ((++cnt % 4) == 0) {
1813 						(*pr)("\n\t");
1814 					}
1815 				}
1816 			}
1817 			(*pr)("\n");
1818 		}
1819 	}
1820 }
1821 
1822 #if defined(WAPBL_DEBUG) || defined(DDB)
1823 void
1824 wapbl_dump(struct wapbl *wl)
1825 {
1826 #if defined(WAPBL_DEBUG)
1827 	if (!wl)
1828 		wl = wapbl_debug_wl;
1829 #endif
1830 	if (!wl)
1831 		return;
1832 	wapbl_print(wl, 1, printf);
1833 }
1834 #endif
1835 
1836 /****************************************************************/
1837 
1838 void
1839 wapbl_register_deallocation(struct wapbl *wl, daddr_t blk, int len)
1840 {
1841 
1842 	wapbl_jlock_assert(wl);
1843 
1844 	mutex_enter(&wl->wl_mtx);
1845 	/* XXX should eventually instead tie this into resource estimation */
1846 	/*
1847 	 * XXX this panic needs locking/mutex analysis and the
1848 	 * ability to cope with the failure.
1849 	 */
1850 	/* XXX this XXX doesn't have enough XXX */
1851 	if (__predict_false(wl->wl_dealloccnt >= wl->wl_dealloclim))
1852 		panic("wapbl_register_deallocation: out of resources");
1853 
1854 	wl->wl_deallocblks[wl->wl_dealloccnt] = blk;
1855 	wl->wl_dealloclens[wl->wl_dealloccnt] = len;
1856 	wl->wl_dealloccnt++;
1857 	WAPBL_PRINTF(WAPBL_PRINT_ALLOC,
1858 	    ("wapbl_register_deallocation: blk=%"PRId64" len=%d\n", blk, len));
1859 	mutex_exit(&wl->wl_mtx);
1860 }
1861 
1862 /****************************************************************/
1863 
1864 static void
1865 wapbl_inodetrk_init(struct wapbl *wl, u_int size)
1866 {
1867 
1868 	wl->wl_inohash = hashinit(size, HASH_LIST, true, &wl->wl_inohashmask);
1869 	if (atomic_inc_uint_nv(&wapbl_ino_pool_refcount) == 1) {
1870 		pool_init(&wapbl_ino_pool, sizeof(struct wapbl_ino), 0, 0, 0,
1871 		    "wapblinopl", &pool_allocator_nointr, IPL_NONE);
1872 	}
1873 }
1874 
1875 static void
1876 wapbl_inodetrk_free(struct wapbl *wl)
1877 {
1878 
1879 	/* XXX this KASSERT needs locking/mutex analysis */
1880 	KASSERT(wl->wl_inohashcnt == 0);
1881 	hashdone(wl->wl_inohash, HASH_LIST, wl->wl_inohashmask);
1882 	if (atomic_dec_uint_nv(&wapbl_ino_pool_refcount) == 0) {
1883 		pool_destroy(&wapbl_ino_pool);
1884 	}
1885 }
1886 
1887 static struct wapbl_ino *
1888 wapbl_inodetrk_get(struct wapbl *wl, ino_t ino)
1889 {
1890 	struct wapbl_ino_head *wih;
1891 	struct wapbl_ino *wi;
1892 
1893 	KASSERT(mutex_owned(&wl->wl_mtx));
1894 
1895 	wih = &wl->wl_inohash[ino & wl->wl_inohashmask];
1896 	LIST_FOREACH(wi, wih, wi_hash) {
1897 		if (ino == wi->wi_ino)
1898 			return wi;
1899 	}
1900 	return 0;
1901 }
1902 
1903 void
1904 wapbl_register_inode(struct wapbl *wl, ino_t ino, mode_t mode)
1905 {
1906 	struct wapbl_ino_head *wih;
1907 	struct wapbl_ino *wi;
1908 
1909 	wi = pool_get(&wapbl_ino_pool, PR_WAITOK);
1910 
1911 	mutex_enter(&wl->wl_mtx);
1912 	if (wapbl_inodetrk_get(wl, ino) == NULL) {
1913 		wi->wi_ino = ino;
1914 		wi->wi_mode = mode;
1915 		wih = &wl->wl_inohash[ino & wl->wl_inohashmask];
1916 		LIST_INSERT_HEAD(wih, wi, wi_hash);
1917 		wl->wl_inohashcnt++;
1918 		WAPBL_PRINTF(WAPBL_PRINT_INODE,
1919 		    ("wapbl_register_inode: ino=%"PRId64"\n", ino));
1920 		mutex_exit(&wl->wl_mtx);
1921 	} else {
1922 		mutex_exit(&wl->wl_mtx);
1923 		pool_put(&wapbl_ino_pool, wi);
1924 	}
1925 }
1926 
1927 void
1928 wapbl_unregister_inode(struct wapbl *wl, ino_t ino, mode_t mode)
1929 {
1930 	struct wapbl_ino *wi;
1931 
1932 	mutex_enter(&wl->wl_mtx);
1933 	wi = wapbl_inodetrk_get(wl, ino);
1934 	if (wi) {
1935 		WAPBL_PRINTF(WAPBL_PRINT_INODE,
1936 		    ("wapbl_unregister_inode: ino=%"PRId64"\n", ino));
1937 		KASSERT(wl->wl_inohashcnt > 0);
1938 		wl->wl_inohashcnt--;
1939 		LIST_REMOVE(wi, wi_hash);
1940 		mutex_exit(&wl->wl_mtx);
1941 
1942 		pool_put(&wapbl_ino_pool, wi);
1943 	} else {
1944 		mutex_exit(&wl->wl_mtx);
1945 	}
1946 }
1947 
1948 /****************************************************************/
1949 
1950 static inline size_t
1951 wapbl_transaction_inodes_len(struct wapbl *wl)
1952 {
1953 	int blocklen = 1<<wl->wl_log_dev_bshift;
1954 	int iph;
1955 
1956 	/* Calculate number of inodes described in a inodelist header */
1957 	iph = (blocklen - offsetof(struct wapbl_wc_inodelist, wc_inodes)) /
1958 	    sizeof(((struct wapbl_wc_inodelist *)0)->wc_inodes[0]);
1959 
1960 	KASSERT(iph > 0);
1961 
1962 	return MAX(1, howmany(wl->wl_inohashcnt, iph)) * blocklen;
1963 }
1964 
1965 
1966 /* Calculate amount of space a transaction will take on disk */
1967 static size_t
1968 wapbl_transaction_len(struct wapbl *wl)
1969 {
1970 	int blocklen = 1<<wl->wl_log_dev_bshift;
1971 	size_t len;
1972 	int bph;
1973 
1974 	/* Calculate number of blocks described in a blocklist header */
1975 	bph = (blocklen - offsetof(struct wapbl_wc_blocklist, wc_blocks)) /
1976 	    sizeof(((struct wapbl_wc_blocklist *)0)->wc_blocks[0]);
1977 
1978 	KASSERT(bph > 0);
1979 
1980 	len = wl->wl_bcount;
1981 	len += howmany(wl->wl_bufcount, bph) * blocklen;
1982 	len += howmany(wl->wl_dealloccnt, bph) * blocklen;
1983 	len += wapbl_transaction_inodes_len(wl);
1984 
1985 	return len;
1986 }
1987 
1988 /*
1989  * wapbl_cache_sync: issue DIOCCACHESYNC
1990  */
1991 static int
1992 wapbl_cache_sync(struct wapbl *wl, const char *msg)
1993 {
1994 	const bool verbose = wapbl_verbose_commit >= 2;
1995 	struct bintime start_time;
1996 	int force = 1;
1997 	int error;
1998 
1999 	if (!wapbl_flush_disk_cache) {
2000 		return 0;
2001 	}
2002 	if (verbose) {
2003 		bintime(&start_time);
2004 	}
2005 	error = VOP_IOCTL(wl->wl_devvp, DIOCCACHESYNC, &force,
2006 	    FWRITE, FSCRED);
2007 	if (error) {
2008 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
2009 		    ("wapbl_cache_sync: DIOCCACHESYNC on dev 0x%x "
2010 		    "returned %d\n", wl->wl_devvp->v_rdev, error));
2011 	}
2012 	if (verbose) {
2013 		struct bintime d;
2014 		struct timespec ts;
2015 
2016 		bintime(&d);
2017 		bintime_sub(&d, &start_time);
2018 		bintime2timespec(&d, &ts);
2019 		printf("wapbl_cache_sync: %s: dev 0x%jx %ju.%09lu\n",
2020 		    msg, (uintmax_t)wl->wl_devvp->v_rdev,
2021 		    (uintmax_t)ts.tv_sec, ts.tv_nsec);
2022 	}
2023 	return error;
2024 }
2025 
2026 /*
2027  * Perform commit operation
2028  *
2029  * Note that generation number incrementation needs to
2030  * be protected against racing with other invocations
2031  * of wapbl_write_commit.  This is ok since this routine
2032  * is only invoked from wapbl_flush
2033  */
2034 static int
2035 wapbl_write_commit(struct wapbl *wl, off_t head, off_t tail)
2036 {
2037 	struct wapbl_wc_header *wc = wl->wl_wc_header;
2038 	struct timespec ts;
2039 	int error;
2040 	daddr_t pbn;
2041 
2042 	error = wapbl_buffered_flush(wl);
2043 	if (error)
2044 		return error;
2045 	/*
2046 	 * flush disk cache to ensure that blocks we've written are actually
2047 	 * written to the stable storage before the commit header.
2048 	 *
2049 	 * XXX Calc checksum here, instead we do this for now
2050 	 */
2051 	wapbl_cache_sync(wl, "1");
2052 
2053 	wc->wc_head = head;
2054 	wc->wc_tail = tail;
2055 	wc->wc_checksum = 0;
2056 	wc->wc_version = 1;
2057 	getnanotime(&ts);
2058 	wc->wc_time = ts.tv_sec;
2059 	wc->wc_timensec = ts.tv_nsec;
2060 
2061 	WAPBL_PRINTF(WAPBL_PRINT_WRITE,
2062 	    ("wapbl_write_commit: head = %"PRIdMAX "tail = %"PRIdMAX"\n",
2063 	    (intmax_t)head, (intmax_t)tail));
2064 
2065 	/*
2066 	 * write the commit header.
2067 	 *
2068 	 * XXX if generation will rollover, then first zero
2069 	 * over second commit header before trying to write both headers.
2070 	 */
2071 
2072 	pbn = wl->wl_logpbn + (wc->wc_generation % 2);
2073 #ifdef _KERNEL
2074 	pbn = btodb(pbn << wc->wc_log_dev_bshift);
2075 #endif
2076 	error = wapbl_buffered_write(wc, wc->wc_len, wl, pbn);
2077 	if (error)
2078 		return error;
2079 	error = wapbl_buffered_flush(wl);
2080 	if (error)
2081 		return error;
2082 
2083 	/*
2084 	 * flush disk cache to ensure that the commit header is actually
2085 	 * written before meta data blocks.
2086 	 */
2087 	wapbl_cache_sync(wl, "2");
2088 
2089 	/*
2090 	 * If the generation number was zero, write it out a second time.
2091 	 * This handles initialization and generation number rollover
2092 	 */
2093 	if (wc->wc_generation++ == 0) {
2094 		error = wapbl_write_commit(wl, head, tail);
2095 		/*
2096 		 * This panic should be able to be removed if we do the
2097 		 * zero'ing mentioned above, and we are certain to roll
2098 		 * back generation number on failure.
2099 		 */
2100 		if (error)
2101 			panic("wapbl_write_commit: error writing duplicate "
2102 			      "log header: %d\n", error);
2103 	}
2104 	return 0;
2105 }
2106 
2107 /* Returns new offset value */
2108 static int
2109 wapbl_write_blocks(struct wapbl *wl, off_t *offp)
2110 {
2111 	struct wapbl_wc_blocklist *wc =
2112 	    (struct wapbl_wc_blocklist *)wl->wl_wc_scratch;
2113 	int blocklen = 1<<wl->wl_log_dev_bshift;
2114 	int bph;
2115 	struct buf *bp;
2116 	off_t off = *offp;
2117 	int error;
2118 	size_t padding;
2119 
2120 	KASSERT(rw_write_held(&wl->wl_rwlock));
2121 
2122 	bph = (blocklen - offsetof(struct wapbl_wc_blocklist, wc_blocks)) /
2123 	    sizeof(((struct wapbl_wc_blocklist *)0)->wc_blocks[0]);
2124 
2125 	bp = LIST_FIRST(&wl->wl_bufs);
2126 
2127 	while (bp) {
2128 		int cnt;
2129 		struct buf *obp = bp;
2130 
2131 		KASSERT(bp->b_flags & B_LOCKED);
2132 
2133 		wc->wc_type = WAPBL_WC_BLOCKS;
2134 		wc->wc_len = blocklen;
2135 		wc->wc_blkcount = 0;
2136 		while (bp && (wc->wc_blkcount < bph)) {
2137 			/*
2138 			 * Make sure all the physical block numbers are up to
2139 			 * date.  If this is not always true on a given
2140 			 * filesystem, then VOP_BMAP must be called.  We
2141 			 * could call VOP_BMAP here, or else in the filesystem
2142 			 * specific flush callback, although neither of those
2143 			 * solutions allow us to take the vnode lock.  If a
2144 			 * filesystem requires that we must take the vnode lock
2145 			 * to call VOP_BMAP, then we can probably do it in
2146 			 * bwrite when the vnode lock should already be held
2147 			 * by the invoking code.
2148 			 */
2149 			KASSERT((bp->b_vp->v_type == VBLK) ||
2150 				 (bp->b_blkno != bp->b_lblkno));
2151 			KASSERT(bp->b_blkno > 0);
2152 
2153 			wc->wc_blocks[wc->wc_blkcount].wc_daddr = bp->b_blkno;
2154 			wc->wc_blocks[wc->wc_blkcount].wc_dlen = bp->b_bcount;
2155 			wc->wc_len += bp->b_bcount;
2156 			wc->wc_blkcount++;
2157 			bp = LIST_NEXT(bp, b_wapbllist);
2158 		}
2159 		if (wc->wc_len % blocklen != 0) {
2160 			padding = blocklen - wc->wc_len % blocklen;
2161 			wc->wc_len += padding;
2162 		} else {
2163 			padding = 0;
2164 		}
2165 
2166 		WAPBL_PRINTF(WAPBL_PRINT_WRITE,
2167 		    ("wapbl_write_blocks: len = %u (padding %zu) off = %"PRIdMAX"\n",
2168 		    wc->wc_len, padding, (intmax_t)off));
2169 
2170 		error = wapbl_circ_write(wl, wc, blocklen, &off);
2171 		if (error)
2172 			return error;
2173 		bp = obp;
2174 		cnt = 0;
2175 		while (bp && (cnt++ < bph)) {
2176 			error = wapbl_circ_write(wl, bp->b_data,
2177 			    bp->b_bcount, &off);
2178 			if (error)
2179 				return error;
2180 			bp = LIST_NEXT(bp, b_wapbllist);
2181 		}
2182 		if (padding) {
2183 			void *zero;
2184 
2185 			zero = wapbl_alloc(padding);
2186 			memset(zero, 0, padding);
2187 			error = wapbl_circ_write(wl, zero, padding, &off);
2188 			wapbl_free(zero, padding);
2189 			if (error)
2190 				return error;
2191 		}
2192 	}
2193 	*offp = off;
2194 	return 0;
2195 }
2196 
2197 static int
2198 wapbl_write_revocations(struct wapbl *wl, off_t *offp)
2199 {
2200 	struct wapbl_wc_blocklist *wc =
2201 	    (struct wapbl_wc_blocklist *)wl->wl_wc_scratch;
2202 	int i;
2203 	int blocklen = 1<<wl->wl_log_dev_bshift;
2204 	int bph;
2205 	off_t off = *offp;
2206 	int error;
2207 
2208 	if (wl->wl_dealloccnt == 0)
2209 		return 0;
2210 
2211 	bph = (blocklen - offsetof(struct wapbl_wc_blocklist, wc_blocks)) /
2212 	    sizeof(((struct wapbl_wc_blocklist *)0)->wc_blocks[0]);
2213 
2214 	i = 0;
2215 	while (i < wl->wl_dealloccnt) {
2216 		wc->wc_type = WAPBL_WC_REVOCATIONS;
2217 		wc->wc_len = blocklen;
2218 		wc->wc_blkcount = 0;
2219 		while ((i < wl->wl_dealloccnt) && (wc->wc_blkcount < bph)) {
2220 			wc->wc_blocks[wc->wc_blkcount].wc_daddr =
2221 			    wl->wl_deallocblks[i];
2222 			wc->wc_blocks[wc->wc_blkcount].wc_dlen =
2223 			    wl->wl_dealloclens[i];
2224 			wc->wc_blkcount++;
2225 			i++;
2226 		}
2227 		WAPBL_PRINTF(WAPBL_PRINT_WRITE,
2228 		    ("wapbl_write_revocations: len = %u off = %"PRIdMAX"\n",
2229 		    wc->wc_len, (intmax_t)off));
2230 		error = wapbl_circ_write(wl, wc, blocklen, &off);
2231 		if (error)
2232 			return error;
2233 	}
2234 	*offp = off;
2235 	return 0;
2236 }
2237 
2238 static int
2239 wapbl_write_inodes(struct wapbl *wl, off_t *offp)
2240 {
2241 	struct wapbl_wc_inodelist *wc =
2242 	    (struct wapbl_wc_inodelist *)wl->wl_wc_scratch;
2243 	int i;
2244 	int blocklen = 1 << wl->wl_log_dev_bshift;
2245 	off_t off = *offp;
2246 	int error;
2247 
2248 	struct wapbl_ino_head *wih;
2249 	struct wapbl_ino *wi;
2250 	int iph;
2251 
2252 	iph = (blocklen - offsetof(struct wapbl_wc_inodelist, wc_inodes)) /
2253 	    sizeof(((struct wapbl_wc_inodelist *)0)->wc_inodes[0]);
2254 
2255 	i = 0;
2256 	wih = &wl->wl_inohash[0];
2257 	wi = 0;
2258 	do {
2259 		wc->wc_type = WAPBL_WC_INODES;
2260 		wc->wc_len = blocklen;
2261 		wc->wc_inocnt = 0;
2262 		wc->wc_clear = (i == 0);
2263 		while ((i < wl->wl_inohashcnt) && (wc->wc_inocnt < iph)) {
2264 			while (!wi) {
2265 				KASSERT((wih - &wl->wl_inohash[0])
2266 				    <= wl->wl_inohashmask);
2267 				wi = LIST_FIRST(wih++);
2268 			}
2269 			wc->wc_inodes[wc->wc_inocnt].wc_inumber = wi->wi_ino;
2270 			wc->wc_inodes[wc->wc_inocnt].wc_imode = wi->wi_mode;
2271 			wc->wc_inocnt++;
2272 			i++;
2273 			wi = LIST_NEXT(wi, wi_hash);
2274 		}
2275 		WAPBL_PRINTF(WAPBL_PRINT_WRITE,
2276 		    ("wapbl_write_inodes: len = %u off = %"PRIdMAX"\n",
2277 		    wc->wc_len, (intmax_t)off));
2278 		error = wapbl_circ_write(wl, wc, blocklen, &off);
2279 		if (error)
2280 			return error;
2281 	} while (i < wl->wl_inohashcnt);
2282 
2283 	*offp = off;
2284 	return 0;
2285 }
2286 
2287 #endif /* _KERNEL */
2288 
2289 /****************************************************************/
2290 
2291 struct wapbl_blk {
2292 	LIST_ENTRY(wapbl_blk) wb_hash;
2293 	daddr_t wb_blk;
2294 	off_t wb_off; /* Offset of this block in the log */
2295 };
2296 #define	WAPBL_BLKPOOL_MIN 83
2297 
2298 static void
2299 wapbl_blkhash_init(struct wapbl_replay *wr, u_int size)
2300 {
2301 	if (size < WAPBL_BLKPOOL_MIN)
2302 		size = WAPBL_BLKPOOL_MIN;
2303 	KASSERT(wr->wr_blkhash == 0);
2304 #ifdef _KERNEL
2305 	wr->wr_blkhash = hashinit(size, HASH_LIST, true, &wr->wr_blkhashmask);
2306 #else /* ! _KERNEL */
2307 	/* Manually implement hashinit */
2308 	{
2309 		unsigned long i, hashsize;
2310 		for (hashsize = 1; hashsize < size; hashsize <<= 1)
2311 			continue;
2312 		wr->wr_blkhash = wapbl_alloc(hashsize * sizeof(*wr->wr_blkhash));
2313 		for (i = 0; i < hashsize; i++)
2314 			LIST_INIT(&wr->wr_blkhash[i]);
2315 		wr->wr_blkhashmask = hashsize - 1;
2316 	}
2317 #endif /* ! _KERNEL */
2318 }
2319 
2320 static void
2321 wapbl_blkhash_free(struct wapbl_replay *wr)
2322 {
2323 	KASSERT(wr->wr_blkhashcnt == 0);
2324 #ifdef _KERNEL
2325 	hashdone(wr->wr_blkhash, HASH_LIST, wr->wr_blkhashmask);
2326 #else /* ! _KERNEL */
2327 	wapbl_free(wr->wr_blkhash,
2328 	    (wr->wr_blkhashmask + 1) * sizeof(*wr->wr_blkhash));
2329 #endif /* ! _KERNEL */
2330 }
2331 
2332 static struct wapbl_blk *
2333 wapbl_blkhash_get(struct wapbl_replay *wr, daddr_t blk)
2334 {
2335 	struct wapbl_blk_head *wbh;
2336 	struct wapbl_blk *wb;
2337 	wbh = &wr->wr_blkhash[blk & wr->wr_blkhashmask];
2338 	LIST_FOREACH(wb, wbh, wb_hash) {
2339 		if (blk == wb->wb_blk)
2340 			return wb;
2341 	}
2342 	return 0;
2343 }
2344 
2345 static void
2346 wapbl_blkhash_ins(struct wapbl_replay *wr, daddr_t blk, off_t off)
2347 {
2348 	struct wapbl_blk_head *wbh;
2349 	struct wapbl_blk *wb;
2350 	wb = wapbl_blkhash_get(wr, blk);
2351 	if (wb) {
2352 		KASSERT(wb->wb_blk == blk);
2353 		wb->wb_off = off;
2354 	} else {
2355 		wb = wapbl_alloc(sizeof(*wb));
2356 		wb->wb_blk = blk;
2357 		wb->wb_off = off;
2358 		wbh = &wr->wr_blkhash[blk & wr->wr_blkhashmask];
2359 		LIST_INSERT_HEAD(wbh, wb, wb_hash);
2360 		wr->wr_blkhashcnt++;
2361 	}
2362 }
2363 
2364 static void
2365 wapbl_blkhash_rem(struct wapbl_replay *wr, daddr_t blk)
2366 {
2367 	struct wapbl_blk *wb = wapbl_blkhash_get(wr, blk);
2368 	if (wb) {
2369 		KASSERT(wr->wr_blkhashcnt > 0);
2370 		wr->wr_blkhashcnt--;
2371 		LIST_REMOVE(wb, wb_hash);
2372 		wapbl_free(wb, sizeof(*wb));
2373 	}
2374 }
2375 
2376 static void
2377 wapbl_blkhash_clear(struct wapbl_replay *wr)
2378 {
2379 	unsigned long i;
2380 	for (i = 0; i <= wr->wr_blkhashmask; i++) {
2381 		struct wapbl_blk *wb;
2382 
2383 		while ((wb = LIST_FIRST(&wr->wr_blkhash[i]))) {
2384 			KASSERT(wr->wr_blkhashcnt > 0);
2385 			wr->wr_blkhashcnt--;
2386 			LIST_REMOVE(wb, wb_hash);
2387 			wapbl_free(wb, sizeof(*wb));
2388 		}
2389 	}
2390 	KASSERT(wr->wr_blkhashcnt == 0);
2391 }
2392 
2393 /****************************************************************/
2394 
2395 static int
2396 wapbl_circ_read(struct wapbl_replay *wr, void *data, size_t len, off_t *offp)
2397 {
2398 	size_t slen;
2399 	off_t off = *offp;
2400 	int error;
2401 	daddr_t pbn;
2402 
2403 	KASSERT(((len >> wr->wr_log_dev_bshift) <<
2404 	    wr->wr_log_dev_bshift) == len);
2405 
2406 	if (off < wr->wr_circ_off)
2407 		off = wr->wr_circ_off;
2408 	slen = wr->wr_circ_off + wr->wr_circ_size - off;
2409 	if (slen < len) {
2410 		pbn = wr->wr_logpbn + (off >> wr->wr_log_dev_bshift);
2411 #ifdef _KERNEL
2412 		pbn = btodb(pbn << wr->wr_log_dev_bshift);
2413 #endif
2414 		error = wapbl_read(data, slen, wr->wr_devvp, pbn);
2415 		if (error)
2416 			return error;
2417 		data = (uint8_t *)data + slen;
2418 		len -= slen;
2419 		off = wr->wr_circ_off;
2420 	}
2421 	pbn = wr->wr_logpbn + (off >> wr->wr_log_dev_bshift);
2422 #ifdef _KERNEL
2423 	pbn = btodb(pbn << wr->wr_log_dev_bshift);
2424 #endif
2425 	error = wapbl_read(data, len, wr->wr_devvp, pbn);
2426 	if (error)
2427 		return error;
2428 	off += len;
2429 	if (off >= wr->wr_circ_off + wr->wr_circ_size)
2430 		off = wr->wr_circ_off;
2431 	*offp = off;
2432 	return 0;
2433 }
2434 
2435 static void
2436 wapbl_circ_advance(struct wapbl_replay *wr, size_t len, off_t *offp)
2437 {
2438 	size_t slen;
2439 	off_t off = *offp;
2440 
2441 	KASSERT(((len >> wr->wr_log_dev_bshift) <<
2442 	    wr->wr_log_dev_bshift) == len);
2443 
2444 	if (off < wr->wr_circ_off)
2445 		off = wr->wr_circ_off;
2446 	slen = wr->wr_circ_off + wr->wr_circ_size - off;
2447 	if (slen < len) {
2448 		len -= slen;
2449 		off = wr->wr_circ_off;
2450 	}
2451 	off += len;
2452 	if (off >= wr->wr_circ_off + wr->wr_circ_size)
2453 		off = wr->wr_circ_off;
2454 	*offp = off;
2455 }
2456 
2457 /****************************************************************/
2458 
2459 int
2460 wapbl_replay_start(struct wapbl_replay **wrp, struct vnode *vp,
2461 	daddr_t off, size_t count, size_t blksize)
2462 {
2463 	struct wapbl_replay *wr;
2464 	int error;
2465 	struct vnode *devvp;
2466 	daddr_t logpbn;
2467 	uint8_t *scratch;
2468 	struct wapbl_wc_header *wch;
2469 	struct wapbl_wc_header *wch2;
2470 	/* Use this until we read the actual log header */
2471 	int log_dev_bshift = ilog2(blksize);
2472 	size_t used;
2473 	daddr_t pbn;
2474 
2475 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY,
2476 	    ("wapbl_replay_start: vp=%p off=%"PRId64 " count=%zu blksize=%zu\n",
2477 	    vp, off, count, blksize));
2478 
2479 	if (off < 0)
2480 		return EINVAL;
2481 
2482 	if (blksize < DEV_BSIZE)
2483 		return EINVAL;
2484 	if (blksize % DEV_BSIZE)
2485 		return EINVAL;
2486 
2487 #ifdef _KERNEL
2488 #if 0
2489 	/* XXX vp->v_size isn't reliably set for VBLK devices,
2490 	 * especially root.  However, we might still want to verify
2491 	 * that the full load is readable */
2492 	if ((off + count) * blksize > vp->v_size)
2493 		return EINVAL;
2494 #endif
2495 	if ((error = VOP_BMAP(vp, off, &devvp, &logpbn, 0)) != 0) {
2496 		return error;
2497 	}
2498 #else /* ! _KERNEL */
2499 	devvp = vp;
2500 	logpbn = off;
2501 #endif /* ! _KERNEL */
2502 
2503 	scratch = wapbl_alloc(MAXBSIZE);
2504 
2505 	pbn = logpbn;
2506 #ifdef _KERNEL
2507 	pbn = btodb(pbn << log_dev_bshift);
2508 #endif
2509 	error = wapbl_read(scratch, 2<<log_dev_bshift, devvp, pbn);
2510 	if (error)
2511 		goto errout;
2512 
2513 	wch = (struct wapbl_wc_header *)scratch;
2514 	wch2 =
2515 	    (struct wapbl_wc_header *)(scratch + (1<<log_dev_bshift));
2516 	/* XXX verify checksums and magic numbers */
2517 	if (wch->wc_type != WAPBL_WC_HEADER) {
2518 		printf("Unrecognized wapbl magic: 0x%08x\n", wch->wc_type);
2519 		error = EFTYPE;
2520 		goto errout;
2521 	}
2522 
2523 	if (wch2->wc_generation > wch->wc_generation)
2524 		wch = wch2;
2525 
2526 	wr = wapbl_calloc(1, sizeof(*wr));
2527 
2528 	wr->wr_logvp = vp;
2529 	wr->wr_devvp = devvp;
2530 	wr->wr_logpbn = logpbn;
2531 
2532 	wr->wr_scratch = scratch;
2533 
2534 	wr->wr_log_dev_bshift = wch->wc_log_dev_bshift;
2535 	wr->wr_fs_dev_bshift = wch->wc_fs_dev_bshift;
2536 	wr->wr_circ_off = wch->wc_circ_off;
2537 	wr->wr_circ_size = wch->wc_circ_size;
2538 	wr->wr_generation = wch->wc_generation;
2539 
2540 	used = wapbl_space_used(wch->wc_circ_size, wch->wc_head, wch->wc_tail);
2541 
2542 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY,
2543 	    ("wapbl_replay: head=%"PRId64" tail=%"PRId64" off=%"PRId64
2544 	    " len=%"PRId64" used=%zu\n",
2545 	    wch->wc_head, wch->wc_tail, wch->wc_circ_off,
2546 	    wch->wc_circ_size, used));
2547 
2548 	wapbl_blkhash_init(wr, (used >> wch->wc_fs_dev_bshift));
2549 
2550 	error = wapbl_replay_process(wr, wch->wc_head, wch->wc_tail);
2551 	if (error) {
2552 		wapbl_replay_stop(wr);
2553 		wapbl_replay_free(wr);
2554 		return error;
2555 	}
2556 
2557 	*wrp = wr;
2558 	return 0;
2559 
2560  errout:
2561 	wapbl_free(scratch, MAXBSIZE);
2562 	return error;
2563 }
2564 
2565 void
2566 wapbl_replay_stop(struct wapbl_replay *wr)
2567 {
2568 
2569 	if (!wapbl_replay_isopen(wr))
2570 		return;
2571 
2572 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY, ("wapbl_replay_stop called\n"));
2573 
2574 	wapbl_free(wr->wr_scratch, MAXBSIZE);
2575 	wr->wr_scratch = NULL;
2576 
2577 	wr->wr_logvp = NULL;
2578 
2579 	wapbl_blkhash_clear(wr);
2580 	wapbl_blkhash_free(wr);
2581 }
2582 
2583 void
2584 wapbl_replay_free(struct wapbl_replay *wr)
2585 {
2586 
2587 	KDASSERT(!wapbl_replay_isopen(wr));
2588 
2589 	if (wr->wr_inodes)
2590 		wapbl_free(wr->wr_inodes,
2591 		    wr->wr_inodescnt * sizeof(wr->wr_inodes[0]));
2592 	wapbl_free(wr, sizeof(*wr));
2593 }
2594 
2595 #ifdef _KERNEL
2596 int
2597 wapbl_replay_isopen1(struct wapbl_replay *wr)
2598 {
2599 
2600 	return wapbl_replay_isopen(wr);
2601 }
2602 #endif
2603 
2604 /*
2605  * calculate the disk address for the i'th block in the wc_blockblist
2606  * offset by j blocks of size blen.
2607  *
2608  * wc_daddr is always a kernel disk address in DEV_BSIZE units that
2609  * was written to the journal.
2610  *
2611  * The kernel needs that address plus the offset in DEV_BSIZE units.
2612  *
2613  * Userland needs that address plus the offset in blen units.
2614  *
2615  */
2616 static daddr_t
2617 wapbl_block_daddr(struct wapbl_wc_blocklist *wc, int i, int j, int blen)
2618 {
2619 	daddr_t pbn;
2620 
2621 #ifdef _KERNEL
2622 	pbn = wc->wc_blocks[i].wc_daddr + btodb(j * blen);
2623 #else
2624 	pbn = dbtob(wc->wc_blocks[i].wc_daddr) / blen + j;
2625 #endif
2626 
2627 	return pbn;
2628 }
2629 
2630 static void
2631 wapbl_replay_process_blocks(struct wapbl_replay *wr, off_t *offp)
2632 {
2633 	struct wapbl_wc_blocklist *wc =
2634 	    (struct wapbl_wc_blocklist *)wr->wr_scratch;
2635 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
2636 	int i, j, n;
2637 
2638 	for (i = 0; i < wc->wc_blkcount; i++) {
2639 		/*
2640 		 * Enter each physical block into the hashtable independently.
2641 		 */
2642 		n = wc->wc_blocks[i].wc_dlen >> wr->wr_fs_dev_bshift;
2643 		for (j = 0; j < n; j++) {
2644 			wapbl_blkhash_ins(wr, wapbl_block_daddr(wc, i, j, fsblklen),
2645 			    *offp);
2646 			wapbl_circ_advance(wr, fsblklen, offp);
2647 		}
2648 	}
2649 }
2650 
2651 static void
2652 wapbl_replay_process_revocations(struct wapbl_replay *wr)
2653 {
2654 	struct wapbl_wc_blocklist *wc =
2655 	    (struct wapbl_wc_blocklist *)wr->wr_scratch;
2656 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
2657 	int i, j, n;
2658 
2659 	for (i = 0; i < wc->wc_blkcount; i++) {
2660 		/*
2661 		 * Remove any blocks found from the hashtable.
2662 		 */
2663 		n = wc->wc_blocks[i].wc_dlen >> wr->wr_fs_dev_bshift;
2664 		for (j = 0; j < n; j++)
2665 			wapbl_blkhash_rem(wr, wapbl_block_daddr(wc, i, j, fsblklen));
2666 	}
2667 }
2668 
2669 static void
2670 wapbl_replay_process_inodes(struct wapbl_replay *wr, off_t oldoff, off_t newoff)
2671 {
2672 	struct wapbl_wc_inodelist *wc =
2673 	    (struct wapbl_wc_inodelist *)wr->wr_scratch;
2674 	void *new_inodes;
2675 	const size_t oldsize = wr->wr_inodescnt * sizeof(wr->wr_inodes[0]);
2676 
2677 	KASSERT(sizeof(wr->wr_inodes[0]) == sizeof(wc->wc_inodes[0]));
2678 
2679 	/*
2680 	 * Keep track of where we found this so location won't be
2681 	 * overwritten.
2682 	 */
2683 	if (wc->wc_clear) {
2684 		wr->wr_inodestail = oldoff;
2685 		wr->wr_inodescnt = 0;
2686 		if (wr->wr_inodes != NULL) {
2687 			wapbl_free(wr->wr_inodes, oldsize);
2688 			wr->wr_inodes = NULL;
2689 		}
2690 	}
2691 	wr->wr_inodeshead = newoff;
2692 	if (wc->wc_inocnt == 0)
2693 		return;
2694 
2695 	new_inodes = wapbl_alloc((wr->wr_inodescnt + wc->wc_inocnt) *
2696 	    sizeof(wr->wr_inodes[0]));
2697 	if (wr->wr_inodes != NULL) {
2698 		memcpy(new_inodes, wr->wr_inodes, oldsize);
2699 		wapbl_free(wr->wr_inodes, oldsize);
2700 	}
2701 	wr->wr_inodes = new_inodes;
2702 	memcpy(&wr->wr_inodes[wr->wr_inodescnt], wc->wc_inodes,
2703 	    wc->wc_inocnt * sizeof(wr->wr_inodes[0]));
2704 	wr->wr_inodescnt += wc->wc_inocnt;
2705 }
2706 
2707 static int
2708 wapbl_replay_process(struct wapbl_replay *wr, off_t head, off_t tail)
2709 {
2710 	off_t off;
2711 	int error;
2712 
2713 	int logblklen = 1 << wr->wr_log_dev_bshift;
2714 
2715 	wapbl_blkhash_clear(wr);
2716 
2717 	off = tail;
2718 	while (off != head) {
2719 		struct wapbl_wc_null *wcn;
2720 		off_t saveoff = off;
2721 		error = wapbl_circ_read(wr, wr->wr_scratch, logblklen, &off);
2722 		if (error)
2723 			goto errout;
2724 		wcn = (struct wapbl_wc_null *)wr->wr_scratch;
2725 		switch (wcn->wc_type) {
2726 		case WAPBL_WC_BLOCKS:
2727 			wapbl_replay_process_blocks(wr, &off);
2728 			break;
2729 
2730 		case WAPBL_WC_REVOCATIONS:
2731 			wapbl_replay_process_revocations(wr);
2732 			break;
2733 
2734 		case WAPBL_WC_INODES:
2735 			wapbl_replay_process_inodes(wr, saveoff, off);
2736 			break;
2737 
2738 		default:
2739 			printf("Unrecognized wapbl type: 0x%08x\n",
2740 			       wcn->wc_type);
2741  			error = EFTYPE;
2742 			goto errout;
2743 		}
2744 		wapbl_circ_advance(wr, wcn->wc_len, &saveoff);
2745 		if (off != saveoff) {
2746 			printf("wapbl_replay: corrupted records\n");
2747 			error = EFTYPE;
2748 			goto errout;
2749 		}
2750 	}
2751 	return 0;
2752 
2753  errout:
2754 	wapbl_blkhash_clear(wr);
2755 	return error;
2756 }
2757 
2758 #if 0
2759 int
2760 wapbl_replay_verify(struct wapbl_replay *wr, struct vnode *fsdevvp)
2761 {
2762 	off_t off;
2763 	int mismatchcnt = 0;
2764 	int logblklen = 1 << wr->wr_log_dev_bshift;
2765 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
2766 	void *scratch1 = wapbl_alloc(MAXBSIZE);
2767 	void *scratch2 = wapbl_alloc(MAXBSIZE);
2768 	int error = 0;
2769 
2770 	KDASSERT(wapbl_replay_isopen(wr));
2771 
2772 	off = wch->wc_tail;
2773 	while (off != wch->wc_head) {
2774 		struct wapbl_wc_null *wcn;
2775 #ifdef DEBUG
2776 		off_t saveoff = off;
2777 #endif
2778 		error = wapbl_circ_read(wr, wr->wr_scratch, logblklen, &off);
2779 		if (error)
2780 			goto out;
2781 		wcn = (struct wapbl_wc_null *)wr->wr_scratch;
2782 		switch (wcn->wc_type) {
2783 		case WAPBL_WC_BLOCKS:
2784 			{
2785 				struct wapbl_wc_blocklist *wc =
2786 				    (struct wapbl_wc_blocklist *)wr->wr_scratch;
2787 				int i;
2788 				for (i = 0; i < wc->wc_blkcount; i++) {
2789 					int foundcnt = 0;
2790 					int dirtycnt = 0;
2791 					int j, n;
2792 					/*
2793 					 * Check each physical block into the
2794 					 * hashtable independently
2795 					 */
2796 					n = wc->wc_blocks[i].wc_dlen >>
2797 					    wch->wc_fs_dev_bshift;
2798 					for (j = 0; j < n; j++) {
2799 						struct wapbl_blk *wb =
2800 						   wapbl_blkhash_get(wr,
2801 						   wapbl_block_daddr(wc, i, j, fsblklen));
2802 						if (wb && (wb->wb_off == off)) {
2803 							foundcnt++;
2804 							error =
2805 							    wapbl_circ_read(wr,
2806 							    scratch1, fsblklen,
2807 							    &off);
2808 							if (error)
2809 								goto out;
2810 							error =
2811 							    wapbl_read(scratch2,
2812 							    fsblklen, fsdevvp,
2813 							    wb->wb_blk);
2814 							if (error)
2815 								goto out;
2816 							if (memcmp(scratch1,
2817 								   scratch2,
2818 								   fsblklen)) {
2819 								printf(
2820 		"wapbl_verify: mismatch block %"PRId64" at off %"PRIdMAX"\n",
2821 		wb->wb_blk, (intmax_t)off);
2822 								dirtycnt++;
2823 								mismatchcnt++;
2824 							}
2825 						} else {
2826 							wapbl_circ_advance(wr,
2827 							    fsblklen, &off);
2828 						}
2829 					}
2830 #if 0
2831 					/*
2832 					 * If all of the blocks in an entry
2833 					 * are clean, then remove all of its
2834 					 * blocks from the hashtable since they
2835 					 * never will need replay.
2836 					 */
2837 					if ((foundcnt != 0) &&
2838 					    (dirtycnt == 0)) {
2839 						off = saveoff;
2840 						wapbl_circ_advance(wr,
2841 						    logblklen, &off);
2842 						for (j = 0; j < n; j++) {
2843 							struct wapbl_blk *wb =
2844 							   wapbl_blkhash_get(wr,
2845 							   wapbl_block_daddr(wc, i, j, fsblklen));
2846 							if (wb &&
2847 							  (wb->wb_off == off)) {
2848 								wapbl_blkhash_rem(wr, wb->wb_blk);
2849 							}
2850 							wapbl_circ_advance(wr,
2851 							    fsblklen, &off);
2852 						}
2853 					}
2854 #endif
2855 				}
2856 			}
2857 			break;
2858 		case WAPBL_WC_REVOCATIONS:
2859 		case WAPBL_WC_INODES:
2860 			break;
2861 		default:
2862 			KASSERT(0);
2863 		}
2864 #ifdef DEBUG
2865 		wapbl_circ_advance(wr, wcn->wc_len, &saveoff);
2866 		KASSERT(off == saveoff);
2867 #endif
2868 	}
2869  out:
2870 	wapbl_free(scratch1, MAXBSIZE);
2871 	wapbl_free(scratch2, MAXBSIZE);
2872 	if (!error && mismatchcnt)
2873 		error = EFTYPE;
2874 	return error;
2875 }
2876 #endif
2877 
2878 int
2879 wapbl_replay_write(struct wapbl_replay *wr, struct vnode *fsdevvp)
2880 {
2881 	struct wapbl_blk *wb;
2882 	size_t i;
2883 	off_t off;
2884 	void *scratch;
2885 	int error = 0;
2886 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
2887 
2888 	KDASSERT(wapbl_replay_isopen(wr));
2889 
2890 	scratch = wapbl_alloc(MAXBSIZE);
2891 
2892 	for (i = 0; i <= wr->wr_blkhashmask; ++i) {
2893 		LIST_FOREACH(wb, &wr->wr_blkhash[i], wb_hash) {
2894 			off = wb->wb_off;
2895 			error = wapbl_circ_read(wr, scratch, fsblklen, &off);
2896 			if (error)
2897 				break;
2898 			error = wapbl_write(scratch, fsblklen, fsdevvp,
2899 			    wb->wb_blk);
2900 			if (error)
2901 				break;
2902 		}
2903 	}
2904 
2905 	wapbl_free(scratch, MAXBSIZE);
2906 	return error;
2907 }
2908 
2909 int
2910 wapbl_replay_can_read(struct wapbl_replay *wr, daddr_t blk, long len)
2911 {
2912 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
2913 
2914 	KDASSERT(wapbl_replay_isopen(wr));
2915 	KASSERT((len % fsblklen) == 0);
2916 
2917 	while (len != 0) {
2918 		struct wapbl_blk *wb = wapbl_blkhash_get(wr, blk);
2919 		if (wb)
2920 			return 1;
2921 		len -= fsblklen;
2922 	}
2923 	return 0;
2924 }
2925 
2926 int
2927 wapbl_replay_read(struct wapbl_replay *wr, void *data, daddr_t blk, long len)
2928 {
2929 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
2930 
2931 	KDASSERT(wapbl_replay_isopen(wr));
2932 
2933 	KASSERT((len % fsblklen) == 0);
2934 
2935 	while (len != 0) {
2936 		struct wapbl_blk *wb = wapbl_blkhash_get(wr, blk);
2937 		if (wb) {
2938 			off_t off = wb->wb_off;
2939 			int error;
2940 			error = wapbl_circ_read(wr, data, fsblklen, &off);
2941 			if (error)
2942 				return error;
2943 		}
2944 		data = (uint8_t *)data + fsblklen;
2945 		len -= fsblklen;
2946 		blk++;
2947 	}
2948 	return 0;
2949 }
2950 
2951 #ifdef _KERNEL
2952 
2953 MODULE(MODULE_CLASS_VFS, wapbl, NULL);
2954 
2955 static int
2956 wapbl_modcmd(modcmd_t cmd, void *arg)
2957 {
2958 
2959 	switch (cmd) {
2960 	case MODULE_CMD_INIT:
2961 		wapbl_init();
2962 		return 0;
2963 	case MODULE_CMD_FINI:
2964 		return wapbl_fini(true);
2965 	default:
2966 		return ENOTTY;
2967 	}
2968 }
2969 #endif /* _KERNEL */
2970