Home | History | Annotate | Line # | Download | only in kern
vfs_wapbl.c revision 1.61.2.5
      1 /*	$NetBSD: vfs_wapbl.c,v 1.61.2.5 2016/12/05 10:55:26 skrll 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 1.61.2.5 2016/12/05 10:55:26 skrll Exp $");
     40 
     41 #include <sys/param.h>
     42 #include <sys/bitops.h>
     43 #include <sys/time.h>
     44 #include <sys/wapbl.h>
     45 #include <sys/wapbl_replay.h>
     46 
     47 #ifdef _KERNEL
     48 
     49 #include <sys/atomic.h>
     50 #include <sys/conf.h>
     51 #include <sys/file.h>
     52 #include <sys/kauth.h>
     53 #include <sys/kernel.h>
     54 #include <sys/module.h>
     55 #include <sys/mount.h>
     56 #include <sys/mutex.h>
     57 #include <sys/namei.h>
     58 #include <sys/proc.h>
     59 #include <sys/resourcevar.h>
     60 #include <sys/sysctl.h>
     61 #include <sys/uio.h>
     62 #include <sys/vnode.h>
     63 
     64 #include <miscfs/specfs/specdev.h>
     65 
     66 #define	wapbl_alloc(s) kmem_alloc((s), KM_SLEEP)
     67 #define	wapbl_free(a, s) kmem_free((a), (s))
     68 #define	wapbl_calloc(n, s) kmem_zalloc((n)*(s), KM_SLEEP)
     69 
     70 static struct sysctllog *wapbl_sysctl;
     71 static int wapbl_flush_disk_cache = 1;
     72 static int wapbl_verbose_commit = 0;
     73 
     74 static inline size_t wapbl_space_free(size_t, off_t, off_t);
     75 
     76 #else /* !_KERNEL */
     77 
     78 #include <assert.h>
     79 #include <errno.h>
     80 #include <stdbool.h>
     81 #include <stdio.h>
     82 #include <stdlib.h>
     83 #include <string.h>
     84 
     85 #define	KDASSERT(x) assert(x)
     86 #define	KASSERT(x) assert(x)
     87 #define	wapbl_alloc(s) malloc(s)
     88 #define	wapbl_free(a, s) free(a)
     89 #define	wapbl_calloc(n, s) calloc((n), (s))
     90 
     91 #endif /* !_KERNEL */
     92 
     93 /*
     94  * INTERNAL DATA STRUCTURES
     95  */
     96 
     97 /*
     98  * This structure holds per-mount log information.
     99  *
    100  * Legend:	a = atomic access only
    101  *		r = read-only after init
    102  *		l = rwlock held
    103  *		m = mutex held
    104  *		lm = rwlock held writing or mutex held
    105  *		u = unlocked access ok
    106  *		b = bufcache_lock held
    107  */
    108 LIST_HEAD(wapbl_ino_head, wapbl_ino);
    109 struct wapbl {
    110 	struct vnode *wl_logvp;	/* r:	log here */
    111 	struct vnode *wl_devvp;	/* r:	log on this device */
    112 	struct mount *wl_mount;	/* r:	mountpoint wl is associated with */
    113 	daddr_t wl_logpbn;	/* r:	Physical block number of start of log */
    114 	int wl_log_dev_bshift;	/* r:	logarithm of device block size of log
    115 					device */
    116 	int wl_fs_dev_bshift;	/* r:	logarithm of device block size of
    117 					filesystem device */
    118 
    119 	unsigned wl_lock_count;	/* m:	Count of transactions in progress */
    120 
    121 	size_t wl_circ_size; 	/* r:	Number of bytes in buffer of log */
    122 	size_t wl_circ_off;	/* r:	Number of bytes reserved at start */
    123 
    124 	size_t wl_bufcount_max;	/* r:	Number of buffers reserved for log */
    125 	size_t wl_bufbytes_max;	/* r:	Number of buf bytes reserved for log */
    126 
    127 	off_t wl_head;		/* l:	Byte offset of log head */
    128 	off_t wl_tail;		/* l:	Byte offset of log tail */
    129 	/*
    130 	 * WAPBL log layout, stored on wl_devvp at wl_logpbn:
    131 	 *
    132 	 *  ___________________ wl_circ_size __________________
    133 	 * /                                                   \
    134 	 * +---------+---------+-------+--------------+--------+
    135 	 * [ commit0 | commit1 | CCWCW | EEEEEEEEEEEE | CCCWCW ]
    136 	 * +---------+---------+-------+--------------+--------+
    137 	 *       wl_circ_off --^       ^-- wl_head    ^-- wl_tail
    138 	 *
    139 	 * commit0 and commit1 are commit headers.  A commit header has
    140 	 * a generation number, indicating which of the two headers is
    141 	 * more recent, and an assignment of head and tail pointers.
    142 	 * The rest is a circular queue of log records, starting at
    143 	 * the byte offset wl_circ_off.
    144 	 *
    145 	 * E marks empty space for records.
    146 	 * W marks records for block writes issued but waiting.
    147 	 * C marks completed records.
    148 	 *
    149 	 * wapbl_flush writes new records to empty `E' spaces after
    150 	 * wl_head from the current transaction in memory.
    151 	 *
    152 	 * wapbl_truncate advances wl_tail past any completed `C'
    153 	 * records, freeing them up for use.
    154 	 *
    155 	 * head == tail == 0 means log is empty.
    156 	 * head == tail != 0 means log is full.
    157 	 *
    158 	 * See assertions in wapbl_advance() for other boundary
    159 	 * conditions.
    160 	 *
    161 	 * Only wapbl_flush moves the head, except when wapbl_truncate
    162 	 * sets it to 0 to indicate that the log is empty.
    163 	 *
    164 	 * Only wapbl_truncate moves the tail, except when wapbl_flush
    165 	 * sets it to wl_circ_off to indicate that the log is full.
    166 	 */
    167 
    168 	struct wapbl_wc_header *wl_wc_header;	/* l	*/
    169 	void *wl_wc_scratch;	/* l:	scratch space (XXX: por que?!?) */
    170 
    171 	kmutex_t wl_mtx;	/* u:	short-term lock */
    172 	krwlock_t wl_rwlock;	/* u:	File system transaction lock */
    173 
    174 	/*
    175 	 * Must be held while accessing
    176 	 * wl_count or wl_bufs or head or tail
    177 	 */
    178 
    179 	/*
    180 	 * Callback called from within the flush routine to flush any extra
    181 	 * bits.  Note that flush may be skipped without calling this if
    182 	 * there are no outstanding buffers in the transaction.
    183 	 */
    184 #if _KERNEL
    185 	wapbl_flush_fn_t wl_flush;	/* r	*/
    186 	wapbl_flush_fn_t wl_flush_abort;/* r	*/
    187 #endif
    188 
    189 	size_t wl_bufbytes;	/* m:	Byte count of pages in wl_bufs */
    190 	size_t wl_bufcount;	/* m:	Count of buffers in wl_bufs */
    191 	size_t wl_bcount;	/* m:	Total bcount of wl_bufs */
    192 
    193 	LIST_HEAD(, buf) wl_bufs; /* m:	Buffers in current transaction */
    194 
    195 	kcondvar_t wl_reclaimable_cv;	/* m (obviously) */
    196 	size_t wl_reclaimable_bytes; /* m:	Amount of space available for
    197 						reclamation by truncate */
    198 	int wl_error_count;	/* m:	# of wl_entries with errors */
    199 	size_t wl_reserved_bytes; /* never truncate log smaller than this */
    200 
    201 #ifdef WAPBL_DEBUG_BUFBYTES
    202 	size_t wl_unsynced_bufbytes; /* Byte count of unsynced buffers */
    203 #endif
    204 
    205 #if _KERNEL
    206 	int wl_brperjblock;	/* r Block records per journal block */
    207 #endif
    208 
    209 	TAILQ_HEAD(, wapbl_dealloc) wl_dealloclist;	/* lm:	list head */
    210 	int wl_dealloccnt;				/* lm:	total count */
    211 	int wl_dealloclim;				/* r:	max count */
    212 
    213 	/* hashtable of inode numbers for allocated but unlinked inodes */
    214 	/* synch ??? */
    215 	struct wapbl_ino_head *wl_inohash;
    216 	u_long wl_inohashmask;
    217 	int wl_inohashcnt;
    218 
    219 	SIMPLEQ_HEAD(, wapbl_entry) wl_entries; /* On disk transaction
    220 						   accounting */
    221 
    222 	u_char *wl_buffer;	/* l:   buffer for wapbl_buffered_write() */
    223 	daddr_t wl_buffer_dblk;	/* l:   buffer disk block address */
    224 	size_t wl_buffer_used;	/* l:   buffer current use */
    225 };
    226 
    227 #ifdef WAPBL_DEBUG_PRINT
    228 int wapbl_debug_print = WAPBL_DEBUG_PRINT;
    229 #endif
    230 
    231 /****************************************************************/
    232 #ifdef _KERNEL
    233 
    234 #ifdef WAPBL_DEBUG
    235 struct wapbl *wapbl_debug_wl;
    236 #endif
    237 
    238 static int wapbl_write_commit(struct wapbl *wl, off_t head, off_t tail);
    239 static int wapbl_write_blocks(struct wapbl *wl, off_t *offp);
    240 static int wapbl_write_revocations(struct wapbl *wl, off_t *offp);
    241 static int wapbl_write_inodes(struct wapbl *wl, off_t *offp);
    242 #endif /* _KERNEL */
    243 
    244 static int wapbl_replay_process(struct wapbl_replay *wr, off_t, off_t);
    245 
    246 static inline size_t wapbl_space_used(size_t avail, off_t head,
    247 	off_t tail);
    248 
    249 #ifdef _KERNEL
    250 
    251 static struct pool wapbl_entry_pool;
    252 static struct pool wapbl_dealloc_pool;
    253 
    254 #define	WAPBL_INODETRK_SIZE 83
    255 static int wapbl_ino_pool_refcount;
    256 static struct pool wapbl_ino_pool;
    257 struct wapbl_ino {
    258 	LIST_ENTRY(wapbl_ino) wi_hash;
    259 	ino_t wi_ino;
    260 	mode_t wi_mode;
    261 };
    262 
    263 static void wapbl_inodetrk_init(struct wapbl *wl, u_int size);
    264 static void wapbl_inodetrk_free(struct wapbl *wl);
    265 static struct wapbl_ino *wapbl_inodetrk_get(struct wapbl *wl, ino_t ino);
    266 
    267 static size_t wapbl_transaction_len(struct wapbl *wl);
    268 static inline size_t wapbl_transaction_inodes_len(struct wapbl *wl);
    269 
    270 static void wapbl_deallocation_free(struct wapbl *, struct wapbl_dealloc *,
    271 	bool);
    272 
    273 #if 0
    274 int wapbl_replay_verify(struct wapbl_replay *, struct vnode *);
    275 #endif
    276 
    277 static int wapbl_replay_isopen1(struct wapbl_replay *);
    278 
    279 struct wapbl_ops wapbl_ops = {
    280 	.wo_wapbl_discard	= wapbl_discard,
    281 	.wo_wapbl_replay_isopen	= wapbl_replay_isopen1,
    282 	.wo_wapbl_replay_can_read = wapbl_replay_can_read,
    283 	.wo_wapbl_replay_read	= wapbl_replay_read,
    284 	.wo_wapbl_add_buf	= wapbl_add_buf,
    285 	.wo_wapbl_remove_buf	= wapbl_remove_buf,
    286 	.wo_wapbl_resize_buf	= wapbl_resize_buf,
    287 	.wo_wapbl_begin		= wapbl_begin,
    288 	.wo_wapbl_end		= wapbl_end,
    289 	.wo_wapbl_junlock_assert= wapbl_junlock_assert,
    290 
    291 	/* XXX: the following is only used to say "this is a wapbl buf" */
    292 	.wo_wapbl_biodone	= wapbl_biodone,
    293 };
    294 
    295 static int
    296 wapbl_sysctl_init(void)
    297 {
    298 	int rv;
    299 	const struct sysctlnode *rnode, *cnode;
    300 
    301 	wapbl_sysctl = NULL;
    302 
    303 	rv = sysctl_createv(&wapbl_sysctl, 0, NULL, &rnode,
    304 		       CTLFLAG_PERMANENT,
    305 		       CTLTYPE_NODE, "wapbl",
    306 		       SYSCTL_DESCR("WAPBL journaling options"),
    307 		       NULL, 0, NULL, 0,
    308 		       CTL_VFS, CTL_CREATE, CTL_EOL);
    309 	if (rv)
    310 		return rv;
    311 
    312 	rv = sysctl_createv(&wapbl_sysctl, 0, &rnode, &cnode,
    313 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
    314 		       CTLTYPE_INT, "flush_disk_cache",
    315 		       SYSCTL_DESCR("flush disk cache"),
    316 		       NULL, 0, &wapbl_flush_disk_cache, 0,
    317 		       CTL_CREATE, CTL_EOL);
    318 	if (rv)
    319 		return rv;
    320 
    321 	rv = sysctl_createv(&wapbl_sysctl, 0, &rnode, &cnode,
    322 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
    323 		       CTLTYPE_INT, "verbose_commit",
    324 		       SYSCTL_DESCR("show time and size of wapbl log commits"),
    325 		       NULL, 0, &wapbl_verbose_commit, 0,
    326 		       CTL_CREATE, CTL_EOL);
    327 	return rv;
    328 }
    329 
    330 static void
    331 wapbl_init(void)
    332 {
    333 
    334 	pool_init(&wapbl_entry_pool, sizeof(struct wapbl_entry), 0, 0, 0,
    335 	    "wapblentrypl", &pool_allocator_kmem, IPL_VM);
    336 	pool_init(&wapbl_dealloc_pool, sizeof(struct wapbl_dealloc), 0, 0, 0,
    337 	    "wapbldealloc", &pool_allocator_nointr, IPL_NONE);
    338 
    339 	wapbl_sysctl_init();
    340 }
    341 
    342 static int
    343 wapbl_fini(void)
    344 {
    345 
    346 	if (wapbl_sysctl != NULL)
    347 		 sysctl_teardown(&wapbl_sysctl);
    348 
    349 	pool_destroy(&wapbl_dealloc_pool);
    350 	pool_destroy(&wapbl_entry_pool);
    351 
    352 	return 0;
    353 }
    354 
    355 static int
    356 wapbl_start_flush_inodes(struct wapbl *wl, struct wapbl_replay *wr)
    357 {
    358 	int error, i;
    359 
    360 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY,
    361 	    ("wapbl_start: reusing log with %d inodes\n", wr->wr_inodescnt));
    362 
    363 	/*
    364 	 * Its only valid to reuse the replay log if its
    365 	 * the same as the new log we just opened.
    366 	 */
    367 	KDASSERT(!wapbl_replay_isopen(wr));
    368 	KASSERT(wl->wl_devvp->v_type == VBLK);
    369 	KASSERT(wr->wr_devvp->v_type == VBLK);
    370 	KASSERT(wl->wl_devvp->v_rdev == wr->wr_devvp->v_rdev);
    371 	KASSERT(wl->wl_logpbn == wr->wr_logpbn);
    372 	KASSERT(wl->wl_circ_size == wr->wr_circ_size);
    373 	KASSERT(wl->wl_circ_off == wr->wr_circ_off);
    374 	KASSERT(wl->wl_log_dev_bshift == wr->wr_log_dev_bshift);
    375 	KASSERT(wl->wl_fs_dev_bshift == wr->wr_fs_dev_bshift);
    376 
    377 	wl->wl_wc_header->wc_generation = wr->wr_generation + 1;
    378 
    379 	for (i = 0; i < wr->wr_inodescnt; i++)
    380 		wapbl_register_inode(wl, wr->wr_inodes[i].wr_inumber,
    381 		    wr->wr_inodes[i].wr_imode);
    382 
    383 	/* Make sure new transaction won't overwrite old inodes list */
    384 	KDASSERT(wapbl_transaction_len(wl) <=
    385 	    wapbl_space_free(wl->wl_circ_size, wr->wr_inodeshead,
    386 	    wr->wr_inodestail));
    387 
    388 	wl->wl_head = wl->wl_tail = wr->wr_inodeshead;
    389 	wl->wl_reclaimable_bytes = wl->wl_reserved_bytes =
    390 	    wapbl_transaction_len(wl);
    391 
    392 	error = wapbl_write_inodes(wl, &wl->wl_head);
    393 	if (error)
    394 		return error;
    395 
    396 	KASSERT(wl->wl_head != wl->wl_tail);
    397 	KASSERT(wl->wl_head != 0);
    398 
    399 	return 0;
    400 }
    401 
    402 int
    403 wapbl_start(struct wapbl ** wlp, struct mount *mp, struct vnode *vp,
    404 	daddr_t off, size_t count, size_t blksize, struct wapbl_replay *wr,
    405 	wapbl_flush_fn_t flushfn, wapbl_flush_fn_t flushabortfn)
    406 {
    407 	struct wapbl *wl;
    408 	struct vnode *devvp;
    409 	daddr_t logpbn;
    410 	int error;
    411 	int log_dev_bshift = ilog2(blksize);
    412 	int fs_dev_bshift = log_dev_bshift;
    413 	int run;
    414 
    415 	WAPBL_PRINTF(WAPBL_PRINT_OPEN, ("wapbl_start: vp=%p off=%" PRId64
    416 	    " count=%zu blksize=%zu\n", vp, off, count, blksize));
    417 
    418 	if (log_dev_bshift > fs_dev_bshift) {
    419 		WAPBL_PRINTF(WAPBL_PRINT_OPEN,
    420 			("wapbl: log device's block size cannot be larger "
    421 			 "than filesystem's\n"));
    422 		/*
    423 		 * Not currently implemented, although it could be if
    424 		 * needed someday.
    425 		 */
    426 		return ENOSYS;
    427 	}
    428 
    429 	if (off < 0)
    430 		return EINVAL;
    431 
    432 	if (blksize < DEV_BSIZE)
    433 		return EINVAL;
    434 	if (blksize % DEV_BSIZE)
    435 		return EINVAL;
    436 
    437 	/* XXXTODO: verify that the full load is writable */
    438 
    439 	/*
    440 	 * XXX check for minimum log size
    441 	 * minimum is governed by minimum amount of space
    442 	 * to complete a transaction. (probably truncate)
    443 	 */
    444 	/* XXX for now pick something minimal */
    445 	if ((count * blksize) < MAXPHYS) {
    446 		return ENOSPC;
    447 	}
    448 
    449 	if ((error = VOP_BMAP(vp, off, &devvp, &logpbn, &run)) != 0) {
    450 		return error;
    451 	}
    452 
    453 	wl = wapbl_calloc(1, sizeof(*wl));
    454 	rw_init(&wl->wl_rwlock);
    455 	mutex_init(&wl->wl_mtx, MUTEX_DEFAULT, IPL_NONE);
    456 	cv_init(&wl->wl_reclaimable_cv, "wapblrec");
    457 	LIST_INIT(&wl->wl_bufs);
    458 	SIMPLEQ_INIT(&wl->wl_entries);
    459 
    460 	wl->wl_logvp = vp;
    461 	wl->wl_devvp = devvp;
    462 	wl->wl_mount = mp;
    463 	wl->wl_logpbn = logpbn;
    464 	wl->wl_log_dev_bshift = log_dev_bshift;
    465 	wl->wl_fs_dev_bshift = fs_dev_bshift;
    466 
    467 	wl->wl_flush = flushfn;
    468 	wl->wl_flush_abort = flushabortfn;
    469 
    470 	/* Reserve two log device blocks for the commit headers */
    471 	wl->wl_circ_off = 2<<wl->wl_log_dev_bshift;
    472 	wl->wl_circ_size = ((count * blksize) - wl->wl_circ_off);
    473 	/* truncate the log usage to a multiple of log_dev_bshift */
    474 	wl->wl_circ_size >>= wl->wl_log_dev_bshift;
    475 	wl->wl_circ_size <<= wl->wl_log_dev_bshift;
    476 
    477 	/*
    478 	 * wl_bufbytes_max limits the size of the in memory transaction space.
    479 	 * - Since buffers are allocated and accounted for in units of
    480 	 *   PAGE_SIZE it is required to be a multiple of PAGE_SIZE
    481 	 *   (i.e. 1<<PAGE_SHIFT)
    482 	 * - Since the log device has to be written in units of
    483 	 *   1<<wl_log_dev_bshift it is required to be a mulitple of
    484 	 *   1<<wl_log_dev_bshift.
    485 	 * - Since filesystem will provide data in units of 1<<wl_fs_dev_bshift,
    486 	 *   it is convenient to be a multiple of 1<<wl_fs_dev_bshift.
    487 	 * Therefore it must be multiple of the least common multiple of those
    488 	 * three quantities.  Fortunately, all of those quantities are
    489 	 * guaranteed to be a power of two, and the least common multiple of
    490 	 * a set of numbers which are all powers of two is simply the maximum
    491 	 * of those numbers.  Finally, the maximum logarithm of a power of two
    492 	 * is the same as the log of the maximum power of two.  So we can do
    493 	 * the following operations to size wl_bufbytes_max:
    494 	 */
    495 
    496 	/* XXX fix actual number of pages reserved per filesystem. */
    497 	wl->wl_bufbytes_max = MIN(wl->wl_circ_size, buf_memcalc() / 2);
    498 
    499 	/* Round wl_bufbytes_max to the largest power of two constraint */
    500 	wl->wl_bufbytes_max >>= PAGE_SHIFT;
    501 	wl->wl_bufbytes_max <<= PAGE_SHIFT;
    502 	wl->wl_bufbytes_max >>= wl->wl_log_dev_bshift;
    503 	wl->wl_bufbytes_max <<= wl->wl_log_dev_bshift;
    504 	wl->wl_bufbytes_max >>= wl->wl_fs_dev_bshift;
    505 	wl->wl_bufbytes_max <<= wl->wl_fs_dev_bshift;
    506 
    507 	/* XXX maybe use filesystem fragment size instead of 1024 */
    508 	/* XXX fix actual number of buffers reserved per filesystem. */
    509 	wl->wl_bufcount_max = (nbuf / 2) * 1024;
    510 
    511 	wl->wl_brperjblock = ((1<<wl->wl_log_dev_bshift)
    512 	    - offsetof(struct wapbl_wc_blocklist, wc_blocks)) /
    513 	    sizeof(((struct wapbl_wc_blocklist *)0)->wc_blocks[0]);
    514 	KASSERT(wl->wl_brperjblock > 0);
    515 
    516 	/* XXX tie this into resource estimation */
    517 	wl->wl_dealloclim = wl->wl_bufbytes_max / mp->mnt_stat.f_bsize / 2;
    518 	TAILQ_INIT(&wl->wl_dealloclist);
    519 
    520 	wl->wl_buffer = wapbl_alloc(MAXPHYS);
    521 	wl->wl_buffer_used = 0;
    522 
    523 	wapbl_inodetrk_init(wl, WAPBL_INODETRK_SIZE);
    524 
    525 	/* Initialize the commit header */
    526 	{
    527 		struct wapbl_wc_header *wc;
    528 		size_t len = 1 << wl->wl_log_dev_bshift;
    529 		wc = wapbl_calloc(1, len);
    530 		wc->wc_type = WAPBL_WC_HEADER;
    531 		wc->wc_len = len;
    532 		wc->wc_circ_off = wl->wl_circ_off;
    533 		wc->wc_circ_size = wl->wl_circ_size;
    534 		/* XXX wc->wc_fsid */
    535 		wc->wc_log_dev_bshift = wl->wl_log_dev_bshift;
    536 		wc->wc_fs_dev_bshift = wl->wl_fs_dev_bshift;
    537 		wl->wl_wc_header = wc;
    538 		wl->wl_wc_scratch = wapbl_alloc(len);
    539 	}
    540 
    541 	/*
    542 	 * if there was an existing set of unlinked but
    543 	 * allocated inodes, preserve it in the new
    544 	 * log.
    545 	 */
    546 	if (wr && wr->wr_inodescnt) {
    547 		error = wapbl_start_flush_inodes(wl, wr);
    548 		if (error)
    549 			goto errout;
    550 	}
    551 
    552 	error = wapbl_write_commit(wl, wl->wl_head, wl->wl_tail);
    553 	if (error) {
    554 		goto errout;
    555 	}
    556 
    557 	*wlp = wl;
    558 #if defined(WAPBL_DEBUG)
    559 	wapbl_debug_wl = wl;
    560 #endif
    561 
    562 	return 0;
    563  errout:
    564 	wapbl_discard(wl);
    565 	wapbl_free(wl->wl_wc_scratch, wl->wl_wc_header->wc_len);
    566 	wapbl_free(wl->wl_wc_header, wl->wl_wc_header->wc_len);
    567 	wapbl_free(wl->wl_buffer, MAXPHYS);
    568 	wapbl_inodetrk_free(wl);
    569 	wapbl_free(wl, sizeof(*wl));
    570 
    571 	return error;
    572 }
    573 
    574 /*
    575  * Like wapbl_flush, only discards the transaction
    576  * completely
    577  */
    578 
    579 void
    580 wapbl_discard(struct wapbl *wl)
    581 {
    582 	struct wapbl_entry *we;
    583 	struct wapbl_dealloc *wd;
    584 	struct buf *bp;
    585 	int i;
    586 
    587 	/*
    588 	 * XXX we may consider using upgrade here
    589 	 * if we want to call flush from inside a transaction
    590 	 */
    591 	rw_enter(&wl->wl_rwlock, RW_WRITER);
    592 	wl->wl_flush(wl->wl_mount, TAILQ_FIRST(&wl->wl_dealloclist));
    593 
    594 #ifdef WAPBL_DEBUG_PRINT
    595 	{
    596 		pid_t pid = -1;
    597 		lwpid_t lid = -1;
    598 		if (curproc)
    599 			pid = curproc->p_pid;
    600 		if (curlwp)
    601 			lid = curlwp->l_lid;
    602 #ifdef WAPBL_DEBUG_BUFBYTES
    603 		WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
    604 		    ("wapbl_discard: thread %d.%d discarding "
    605 		    "transaction\n"
    606 		    "\tbufcount=%zu bufbytes=%zu bcount=%zu "
    607 		    "deallocs=%d inodes=%d\n"
    608 		    "\terrcnt = %u, reclaimable=%zu reserved=%zu "
    609 		    "unsynced=%zu\n",
    610 		    pid, lid, wl->wl_bufcount, wl->wl_bufbytes,
    611 		    wl->wl_bcount, wl->wl_dealloccnt,
    612 		    wl->wl_inohashcnt, wl->wl_error_count,
    613 		    wl->wl_reclaimable_bytes, wl->wl_reserved_bytes,
    614 		    wl->wl_unsynced_bufbytes));
    615 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
    616 			WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
    617 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
    618 			     "error = %d, unsynced = %zu\n",
    619 			     we->we_bufcount, we->we_reclaimable_bytes,
    620 			     we->we_error, we->we_unsynced_bufbytes));
    621 		}
    622 #else /* !WAPBL_DEBUG_BUFBYTES */
    623 		WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
    624 		    ("wapbl_discard: thread %d.%d discarding transaction\n"
    625 		    "\tbufcount=%zu bufbytes=%zu bcount=%zu "
    626 		    "deallocs=%d inodes=%d\n"
    627 		    "\terrcnt = %u, reclaimable=%zu reserved=%zu\n",
    628 		    pid, lid, wl->wl_bufcount, wl->wl_bufbytes,
    629 		    wl->wl_bcount, wl->wl_dealloccnt,
    630 		    wl->wl_inohashcnt, wl->wl_error_count,
    631 		    wl->wl_reclaimable_bytes, wl->wl_reserved_bytes));
    632 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
    633 			WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
    634 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
    635 			     "error = %d\n",
    636 			     we->we_bufcount, we->we_reclaimable_bytes,
    637 			     we->we_error));
    638 		}
    639 #endif /* !WAPBL_DEBUG_BUFBYTES */
    640 	}
    641 #endif /* WAPBL_DEBUG_PRINT */
    642 
    643 	for (i = 0; i <= wl->wl_inohashmask; i++) {
    644 		struct wapbl_ino_head *wih;
    645 		struct wapbl_ino *wi;
    646 
    647 		wih = &wl->wl_inohash[i];
    648 		while ((wi = LIST_FIRST(wih)) != NULL) {
    649 			LIST_REMOVE(wi, wi_hash);
    650 			pool_put(&wapbl_ino_pool, wi);
    651 			KASSERT(wl->wl_inohashcnt > 0);
    652 			wl->wl_inohashcnt--;
    653 		}
    654 	}
    655 
    656 	/*
    657 	 * clean buffer list
    658 	 */
    659 	mutex_enter(&bufcache_lock);
    660 	mutex_enter(&wl->wl_mtx);
    661 	while ((bp = LIST_FIRST(&wl->wl_bufs)) != NULL) {
    662 		if (bbusy(bp, 0, 0, &wl->wl_mtx) == 0) {
    663 			/*
    664 			 * The buffer will be unlocked and
    665 			 * removed from the transaction in brelse
    666 			 */
    667 			mutex_exit(&wl->wl_mtx);
    668 			brelsel(bp, 0);
    669 			mutex_enter(&wl->wl_mtx);
    670 		}
    671 	}
    672 	mutex_exit(&wl->wl_mtx);
    673 	mutex_exit(&bufcache_lock);
    674 
    675 	/*
    676 	 * Remove references to this wl from wl_entries, free any which
    677 	 * no longer have buffers, others will be freed in wapbl_biodone
    678 	 * when they no longer have any buffers.
    679 	 */
    680 	while ((we = SIMPLEQ_FIRST(&wl->wl_entries)) != NULL) {
    681 		SIMPLEQ_REMOVE_HEAD(&wl->wl_entries, we_entries);
    682 		/* XXX should we be accumulating wl_error_count
    683 		 * and increasing reclaimable bytes ? */
    684 		we->we_wapbl = NULL;
    685 		if (we->we_bufcount == 0) {
    686 #ifdef WAPBL_DEBUG_BUFBYTES
    687 			KASSERT(we->we_unsynced_bufbytes == 0);
    688 #endif
    689 			pool_put(&wapbl_entry_pool, we);
    690 		}
    691 	}
    692 
    693 	/* Discard list of deallocs */
    694 	while ((wd = TAILQ_FIRST(&wl->wl_dealloclist)) != NULL)
    695 		wapbl_deallocation_free(wl, wd, true);
    696 
    697 	/* XXX should we clear wl_reserved_bytes? */
    698 
    699 	KASSERT(wl->wl_bufbytes == 0);
    700 	KASSERT(wl->wl_bcount == 0);
    701 	KASSERT(wl->wl_bufcount == 0);
    702 	KASSERT(LIST_EMPTY(&wl->wl_bufs));
    703 	KASSERT(SIMPLEQ_EMPTY(&wl->wl_entries));
    704 	KASSERT(wl->wl_inohashcnt == 0);
    705 	KASSERT(TAILQ_EMPTY(&wl->wl_dealloclist));
    706 	KASSERT(wl->wl_dealloccnt == 0);
    707 
    708 	rw_exit(&wl->wl_rwlock);
    709 }
    710 
    711 int
    712 wapbl_stop(struct wapbl *wl, int force)
    713 {
    714 	int error;
    715 
    716 	WAPBL_PRINTF(WAPBL_PRINT_OPEN, ("wapbl_stop called\n"));
    717 	error = wapbl_flush(wl, 1);
    718 	if (error) {
    719 		if (force)
    720 			wapbl_discard(wl);
    721 		else
    722 			return error;
    723 	}
    724 
    725 	/* Unlinked inodes persist after a flush */
    726 	if (wl->wl_inohashcnt) {
    727 		if (force) {
    728 			wapbl_discard(wl);
    729 		} else {
    730 			return EBUSY;
    731 		}
    732 	}
    733 
    734 	KASSERT(wl->wl_bufbytes == 0);
    735 	KASSERT(wl->wl_bcount == 0);
    736 	KASSERT(wl->wl_bufcount == 0);
    737 	KASSERT(LIST_EMPTY(&wl->wl_bufs));
    738 	KASSERT(wl->wl_dealloccnt == 0);
    739 	KASSERT(SIMPLEQ_EMPTY(&wl->wl_entries));
    740 	KASSERT(wl->wl_inohashcnt == 0);
    741 	KASSERT(TAILQ_EMPTY(&wl->wl_dealloclist));
    742 	KASSERT(wl->wl_dealloccnt == 0);
    743 
    744 	wapbl_free(wl->wl_wc_scratch, wl->wl_wc_header->wc_len);
    745 	wapbl_free(wl->wl_wc_header, wl->wl_wc_header->wc_len);
    746 	wapbl_free(wl->wl_buffer, MAXPHYS);
    747 	wapbl_inodetrk_free(wl);
    748 
    749 	cv_destroy(&wl->wl_reclaimable_cv);
    750 	mutex_destroy(&wl->wl_mtx);
    751 	rw_destroy(&wl->wl_rwlock);
    752 	wapbl_free(wl, sizeof(*wl));
    753 
    754 	return 0;
    755 }
    756 
    757 /****************************************************************/
    758 /*
    759  * Unbuffered disk I/O
    760  */
    761 
    762 static int
    763 wapbl_doio(void *data, size_t len, struct vnode *devvp, daddr_t pbn, int flags)
    764 {
    765 	struct pstats *pstats = curlwp->l_proc->p_stats;
    766 	struct buf *bp;
    767 	int error;
    768 
    769 	KASSERT((flags & ~(B_WRITE | B_READ)) == 0);
    770 	KASSERT(devvp->v_type == VBLK);
    771 
    772 	if ((flags & (B_WRITE | B_READ)) == B_WRITE) {
    773 		mutex_enter(devvp->v_interlock);
    774 		devvp->v_numoutput++;
    775 		mutex_exit(devvp->v_interlock);
    776 		pstats->p_ru.ru_oublock++;
    777 	} else {
    778 		pstats->p_ru.ru_inblock++;
    779 	}
    780 
    781 	bp = getiobuf(devvp, true);
    782 	bp->b_flags = flags;
    783 	bp->b_cflags = BC_BUSY; /* silly & dubious */
    784 	bp->b_dev = devvp->v_rdev;
    785 	bp->b_data = data;
    786 	bp->b_bufsize = bp->b_resid = bp->b_bcount = len;
    787 	bp->b_blkno = pbn;
    788 	BIO_SETPRIO(bp, BPRIO_TIMECRITICAL);
    789 
    790 	WAPBL_PRINTF(WAPBL_PRINT_IO,
    791 	    ("wapbl_doio: %s %d bytes at block %"PRId64" on dev 0x%"PRIx64"\n",
    792 	    BUF_ISWRITE(bp) ? "write" : "read", bp->b_bcount,
    793 	    bp->b_blkno, bp->b_dev));
    794 
    795 	VOP_STRATEGY(devvp, bp);
    796 
    797 	error = biowait(bp);
    798 	putiobuf(bp);
    799 
    800 	if (error) {
    801 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
    802 		    ("wapbl_doio: %s %zu bytes at block %" PRId64
    803 		    " on dev 0x%"PRIx64" failed with error %d\n",
    804 		    (((flags & (B_WRITE | B_READ)) == B_WRITE) ?
    805 		     "write" : "read"),
    806 		    len, pbn, devvp->v_rdev, error));
    807 	}
    808 
    809 	return error;
    810 }
    811 
    812 /*
    813  * wapbl_write(data, len, devvp, pbn)
    814  *
    815  *	Synchronously write len bytes from data to physical block pbn
    816  *	on devvp.
    817  */
    818 int
    819 wapbl_write(void *data, size_t len, struct vnode *devvp, daddr_t pbn)
    820 {
    821 
    822 	return wapbl_doio(data, len, devvp, pbn, B_WRITE);
    823 }
    824 
    825 /*
    826  * wapbl_read(data, len, devvp, pbn)
    827  *
    828  *	Synchronously read len bytes into data from physical block pbn
    829  *	on devvp.
    830  */
    831 int
    832 wapbl_read(void *data, size_t len, struct vnode *devvp, daddr_t pbn)
    833 {
    834 
    835 	return wapbl_doio(data, len, devvp, pbn, B_READ);
    836 }
    837 
    838 /****************************************************************/
    839 /*
    840  * Buffered disk writes -- try to coalesce writes and emit
    841  * MAXPHYS-aligned blocks.
    842  */
    843 
    844 /*
    845  * wapbl_buffered_flush(wl)
    846  *
    847  *	Flush any buffered writes from wapbl_buffered_write.
    848  */
    849 static int
    850 wapbl_buffered_flush(struct wapbl *wl)
    851 {
    852 	int error;
    853 
    854 	if (wl->wl_buffer_used == 0)
    855 		return 0;
    856 
    857 	error = wapbl_doio(wl->wl_buffer, wl->wl_buffer_used,
    858 	    wl->wl_devvp, wl->wl_buffer_dblk, B_WRITE);
    859 	wl->wl_buffer_used = 0;
    860 
    861 	return error;
    862 }
    863 
    864 /*
    865  * wapbl_buffered_write(data, len, wl, pbn)
    866  *
    867  *	Write len bytes from data to physical block pbn on
    868  *	wl->wl_devvp.  The write may not complete until
    869  *	wapbl_buffered_flush.
    870  */
    871 static int
    872 wapbl_buffered_write(void *data, size_t len, struct wapbl *wl, daddr_t pbn)
    873 {
    874 	int error;
    875 	size_t resid;
    876 
    877 	/*
    878 	 * If not adjacent to buffered data flush first.  Disk block
    879 	 * address is always valid for non-empty buffer.
    880 	 */
    881 	if (wl->wl_buffer_used > 0 &&
    882 	    pbn != wl->wl_buffer_dblk + btodb(wl->wl_buffer_used)) {
    883 		error = wapbl_buffered_flush(wl);
    884 		if (error)
    885 			return error;
    886 	}
    887 	/*
    888 	 * If this write goes to an empty buffer we have to
    889 	 * save the disk block address first.
    890 	 */
    891 	if (wl->wl_buffer_used == 0)
    892 		wl->wl_buffer_dblk = pbn;
    893 	/*
    894 	 * Remaining space so this buffer ends on a MAXPHYS boundary.
    895 	 *
    896 	 * Cannot become less or equal zero as the buffer would have been
    897 	 * flushed on the last call then.
    898 	 */
    899 	resid = MAXPHYS - dbtob(wl->wl_buffer_dblk % btodb(MAXPHYS)) -
    900 	    wl->wl_buffer_used;
    901 	KASSERT(resid > 0);
    902 	KASSERT(dbtob(btodb(resid)) == resid);
    903 	if (len >= resid) {
    904 		memcpy(wl->wl_buffer + wl->wl_buffer_used, data, resid);
    905 		wl->wl_buffer_used += resid;
    906 		error = wapbl_doio(wl->wl_buffer, wl->wl_buffer_used,
    907 		    wl->wl_devvp, wl->wl_buffer_dblk, B_WRITE);
    908 		data = (uint8_t *)data + resid;
    909 		len -= resid;
    910 		wl->wl_buffer_dblk = pbn + btodb(resid);
    911 		wl->wl_buffer_used = 0;
    912 		if (error)
    913 			return error;
    914 	}
    915 	KASSERT(len < MAXPHYS);
    916 	if (len > 0) {
    917 		memcpy(wl->wl_buffer + wl->wl_buffer_used, data, len);
    918 		wl->wl_buffer_used += len;
    919 	}
    920 
    921 	return 0;
    922 }
    923 
    924 /*
    925  * wapbl_circ_write(wl, data, len, offp)
    926  *
    927  *	Write len bytes from data to the circular queue of wl, starting
    928  *	at linear byte offset *offp, and returning the new linear byte
    929  *	offset in *offp.
    930  *
    931  *	If the starting linear byte offset precedes wl->wl_circ_off,
    932  *	the write instead begins at wl->wl_circ_off.  XXX WTF?  This
    933  *	should be a KASSERT, not a conditional.
    934  *
    935  *	The write is buffered in wl and must be flushed with
    936  *	wapbl_buffered_flush before it will be submitted to the disk.
    937  */
    938 static int
    939 wapbl_circ_write(struct wapbl *wl, void *data, size_t len, off_t *offp)
    940 {
    941 	size_t slen;
    942 	off_t off = *offp;
    943 	int error;
    944 	daddr_t pbn;
    945 
    946 	KDASSERT(((len >> wl->wl_log_dev_bshift) <<
    947 	    wl->wl_log_dev_bshift) == len);
    948 
    949 	if (off < wl->wl_circ_off)
    950 		off = wl->wl_circ_off;
    951 	slen = wl->wl_circ_off + wl->wl_circ_size - off;
    952 	if (slen < len) {
    953 		pbn = wl->wl_logpbn + (off >> wl->wl_log_dev_bshift);
    954 #ifdef _KERNEL
    955 		pbn = btodb(pbn << wl->wl_log_dev_bshift);
    956 #endif
    957 		error = wapbl_buffered_write(data, slen, wl, pbn);
    958 		if (error)
    959 			return error;
    960 		data = (uint8_t *)data + slen;
    961 		len -= slen;
    962 		off = wl->wl_circ_off;
    963 	}
    964 	pbn = wl->wl_logpbn + (off >> wl->wl_log_dev_bshift);
    965 #ifdef _KERNEL
    966 	pbn = btodb(pbn << wl->wl_log_dev_bshift);
    967 #endif
    968 	error = wapbl_buffered_write(data, len, wl, pbn);
    969 	if (error)
    970 		return error;
    971 	off += len;
    972 	if (off >= wl->wl_circ_off + wl->wl_circ_size)
    973 		off = wl->wl_circ_off;
    974 	*offp = off;
    975 	return 0;
    976 }
    977 
    978 /****************************************************************/
    979 /*
    980  * WAPBL transactions: entering, adding/removing bufs, and exiting
    981  */
    982 
    983 int
    984 wapbl_begin(struct wapbl *wl, const char *file, int line)
    985 {
    986 	int doflush;
    987 	unsigned lockcount;
    988 
    989 	KDASSERT(wl);
    990 
    991 	/*
    992 	 * XXX this needs to be made much more sophisticated.
    993 	 * perhaps each wapbl_begin could reserve a specified
    994 	 * number of buffers and bytes.
    995 	 */
    996 	mutex_enter(&wl->wl_mtx);
    997 	lockcount = wl->wl_lock_count;
    998 	doflush = ((wl->wl_bufbytes + (lockcount * MAXPHYS)) >
    999 		   wl->wl_bufbytes_max / 2) ||
   1000 		  ((wl->wl_bufcount + (lockcount * 10)) >
   1001 		   wl->wl_bufcount_max / 2) ||
   1002 		  (wapbl_transaction_len(wl) > wl->wl_circ_size / 2) ||
   1003 		  (wl->wl_dealloccnt >= (wl->wl_dealloclim / 2));
   1004 	mutex_exit(&wl->wl_mtx);
   1005 
   1006 	if (doflush) {
   1007 		WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
   1008 		    ("force flush lockcnt=%d bufbytes=%zu "
   1009 		    "(max=%zu) bufcount=%zu (max=%zu) "
   1010 		    "dealloccnt %d (lim=%d)\n",
   1011 		    lockcount, wl->wl_bufbytes,
   1012 		    wl->wl_bufbytes_max, wl->wl_bufcount,
   1013 		    wl->wl_bufcount_max,
   1014 		    wl->wl_dealloccnt, wl->wl_dealloclim));
   1015 	}
   1016 
   1017 	if (doflush) {
   1018 		int error = wapbl_flush(wl, 0);
   1019 		if (error)
   1020 			return error;
   1021 	}
   1022 
   1023 	rw_enter(&wl->wl_rwlock, RW_READER);
   1024 	mutex_enter(&wl->wl_mtx);
   1025 	wl->wl_lock_count++;
   1026 	mutex_exit(&wl->wl_mtx);
   1027 
   1028 #if defined(WAPBL_DEBUG_PRINT)
   1029 	WAPBL_PRINTF(WAPBL_PRINT_TRANSACTION,
   1030 	    ("wapbl_begin thread %d.%d with bufcount=%zu "
   1031 	    "bufbytes=%zu bcount=%zu at %s:%d\n",
   1032 	    curproc->p_pid, curlwp->l_lid, wl->wl_bufcount,
   1033 	    wl->wl_bufbytes, wl->wl_bcount, file, line));
   1034 #endif
   1035 
   1036 	return 0;
   1037 }
   1038 
   1039 void
   1040 wapbl_end(struct wapbl *wl)
   1041 {
   1042 
   1043 #if defined(WAPBL_DEBUG_PRINT)
   1044 	WAPBL_PRINTF(WAPBL_PRINT_TRANSACTION,
   1045 	     ("wapbl_end thread %d.%d with bufcount=%zu "
   1046 	      "bufbytes=%zu bcount=%zu\n",
   1047 	      curproc->p_pid, curlwp->l_lid, wl->wl_bufcount,
   1048 	      wl->wl_bufbytes, wl->wl_bcount));
   1049 #endif
   1050 
   1051 	/*
   1052 	 * XXX this could be handled more gracefully, perhaps place
   1053 	 * only a partial transaction in the log and allow the
   1054 	 * remaining to flush without the protection of the journal.
   1055 	 */
   1056 	KASSERTMSG((wapbl_transaction_len(wl) <=
   1057 		(wl->wl_circ_size - wl->wl_reserved_bytes)),
   1058 	    "wapbl_end: current transaction too big to flush");
   1059 
   1060 	mutex_enter(&wl->wl_mtx);
   1061 	KASSERT(wl->wl_lock_count > 0);
   1062 	wl->wl_lock_count--;
   1063 	mutex_exit(&wl->wl_mtx);
   1064 
   1065 	rw_exit(&wl->wl_rwlock);
   1066 }
   1067 
   1068 void
   1069 wapbl_add_buf(struct wapbl *wl, struct buf * bp)
   1070 {
   1071 
   1072 	KASSERT(bp->b_cflags & BC_BUSY);
   1073 	KASSERT(bp->b_vp);
   1074 
   1075 	wapbl_jlock_assert(wl);
   1076 
   1077 #if 0
   1078 	/*
   1079 	 * XXX this might be an issue for swapfiles.
   1080 	 * see uvm_swap.c:1702
   1081 	 *
   1082 	 * XXX2 why require it then?  leap of semantics?
   1083 	 */
   1084 	KASSERT((bp->b_cflags & BC_NOCACHE) == 0);
   1085 #endif
   1086 
   1087 	mutex_enter(&wl->wl_mtx);
   1088 	if (bp->b_flags & B_LOCKED) {
   1089 		LIST_REMOVE(bp, b_wapbllist);
   1090 		WAPBL_PRINTF(WAPBL_PRINT_BUFFER2,
   1091 		   ("wapbl_add_buf thread %d.%d re-adding buf %p "
   1092 		    "with %d bytes %d bcount\n",
   1093 		    curproc->p_pid, curlwp->l_lid, bp, bp->b_bufsize,
   1094 		    bp->b_bcount));
   1095 	} else {
   1096 		/* unlocked by dirty buffers shouldn't exist */
   1097 		KASSERT(!(bp->b_oflags & BO_DELWRI));
   1098 		wl->wl_bufbytes += bp->b_bufsize;
   1099 		wl->wl_bcount += bp->b_bcount;
   1100 		wl->wl_bufcount++;
   1101 		WAPBL_PRINTF(WAPBL_PRINT_BUFFER,
   1102 		   ("wapbl_add_buf thread %d.%d adding buf %p "
   1103 		    "with %d bytes %d bcount\n",
   1104 		    curproc->p_pid, curlwp->l_lid, bp, bp->b_bufsize,
   1105 		    bp->b_bcount));
   1106 	}
   1107 	LIST_INSERT_HEAD(&wl->wl_bufs, bp, b_wapbllist);
   1108 	mutex_exit(&wl->wl_mtx);
   1109 
   1110 	bp->b_flags |= B_LOCKED;
   1111 }
   1112 
   1113 static void
   1114 wapbl_remove_buf_locked(struct wapbl * wl, struct buf *bp)
   1115 {
   1116 
   1117 	KASSERT(mutex_owned(&wl->wl_mtx));
   1118 	KASSERT(bp->b_cflags & BC_BUSY);
   1119 	wapbl_jlock_assert(wl);
   1120 
   1121 #if 0
   1122 	/*
   1123 	 * XXX this might be an issue for swapfiles.
   1124 	 * see uvm_swap.c:1725
   1125 	 *
   1126 	 * XXXdeux: see above
   1127 	 */
   1128 	KASSERT((bp->b_flags & BC_NOCACHE) == 0);
   1129 #endif
   1130 	KASSERT(bp->b_flags & B_LOCKED);
   1131 
   1132 	WAPBL_PRINTF(WAPBL_PRINT_BUFFER,
   1133 	   ("wapbl_remove_buf thread %d.%d removing buf %p with "
   1134 	    "%d bytes %d bcount\n",
   1135 	    curproc->p_pid, curlwp->l_lid, bp, bp->b_bufsize, bp->b_bcount));
   1136 
   1137 	KASSERT(wl->wl_bufbytes >= bp->b_bufsize);
   1138 	wl->wl_bufbytes -= bp->b_bufsize;
   1139 	KASSERT(wl->wl_bcount >= bp->b_bcount);
   1140 	wl->wl_bcount -= bp->b_bcount;
   1141 	KASSERT(wl->wl_bufcount > 0);
   1142 	wl->wl_bufcount--;
   1143 	KASSERT((wl->wl_bufcount == 0) == (wl->wl_bufbytes == 0));
   1144 	KASSERT((wl->wl_bufcount == 0) == (wl->wl_bcount == 0));
   1145 	LIST_REMOVE(bp, b_wapbllist);
   1146 
   1147 	bp->b_flags &= ~B_LOCKED;
   1148 }
   1149 
   1150 /* called from brelsel() in vfs_bio among other places */
   1151 void
   1152 wapbl_remove_buf(struct wapbl * wl, struct buf *bp)
   1153 {
   1154 
   1155 	mutex_enter(&wl->wl_mtx);
   1156 	wapbl_remove_buf_locked(wl, bp);
   1157 	mutex_exit(&wl->wl_mtx);
   1158 }
   1159 
   1160 void
   1161 wapbl_resize_buf(struct wapbl *wl, struct buf *bp, long oldsz, long oldcnt)
   1162 {
   1163 
   1164 	KASSERT(bp->b_cflags & BC_BUSY);
   1165 
   1166 	/*
   1167 	 * XXX: why does this depend on B_LOCKED?  otherwise the buf
   1168 	 * is not for a transaction?  if so, why is this called in the
   1169 	 * first place?
   1170 	 */
   1171 	if (bp->b_flags & B_LOCKED) {
   1172 		mutex_enter(&wl->wl_mtx);
   1173 		wl->wl_bufbytes += bp->b_bufsize - oldsz;
   1174 		wl->wl_bcount += bp->b_bcount - oldcnt;
   1175 		mutex_exit(&wl->wl_mtx);
   1176 	}
   1177 }
   1178 
   1179 #endif /* _KERNEL */
   1180 
   1181 /****************************************************************/
   1182 /* Some utility inlines */
   1183 
   1184 /*
   1185  * wapbl_space_used(avail, head, tail)
   1186  *
   1187  *	Number of bytes used in a circular queue of avail total bytes,
   1188  *	from tail to head.
   1189  */
   1190 static inline size_t
   1191 wapbl_space_used(size_t avail, off_t head, off_t tail)
   1192 {
   1193 
   1194 	if (tail == 0) {
   1195 		KASSERT(head == 0);
   1196 		return 0;
   1197 	}
   1198 	return ((head + (avail - 1) - tail) % avail) + 1;
   1199 }
   1200 
   1201 #ifdef _KERNEL
   1202 /*
   1203  * wapbl_advance(size, off, oldoff, delta)
   1204  *
   1205  *	Given a byte offset oldoff into a circular queue of size bytes
   1206  *	starting at off, return a new byte offset oldoff + delta into
   1207  *	the circular queue.
   1208  */
   1209 static inline off_t
   1210 wapbl_advance(size_t size, size_t off, off_t oldoff, size_t delta)
   1211 {
   1212 	off_t newoff;
   1213 
   1214 	/* Define acceptable ranges for inputs. */
   1215 	KASSERT(delta <= (size_t)size);
   1216 	KASSERT((oldoff == 0) || ((size_t)oldoff >= off));
   1217 	KASSERT(oldoff < (off_t)(size + off));
   1218 
   1219 	if ((oldoff == 0) && (delta != 0))
   1220 		newoff = off + delta;
   1221 	else if ((oldoff + delta) < (size + off))
   1222 		newoff = oldoff + delta;
   1223 	else
   1224 		newoff = (oldoff + delta) - size;
   1225 
   1226 	/* Note some interesting axioms */
   1227 	KASSERT((delta != 0) || (newoff == oldoff));
   1228 	KASSERT((delta == 0) || (newoff != 0));
   1229 	KASSERT((delta != (size)) || (newoff == oldoff));
   1230 
   1231 	/* Define acceptable ranges for output. */
   1232 	KASSERT((newoff == 0) || ((size_t)newoff >= off));
   1233 	KASSERT((size_t)newoff < (size + off));
   1234 	return newoff;
   1235 }
   1236 
   1237 /*
   1238  * wapbl_space_free(avail, head, tail)
   1239  *
   1240  *	Number of bytes free in a circular queue of avail total bytes,
   1241  *	in which everything from tail to head is used.
   1242  */
   1243 static inline size_t
   1244 wapbl_space_free(size_t avail, off_t head, off_t tail)
   1245 {
   1246 
   1247 	return avail - wapbl_space_used(avail, head, tail);
   1248 }
   1249 
   1250 /*
   1251  * wapbl_advance_head(size, off, delta, headp, tailp)
   1252  *
   1253  *	In a circular queue of size bytes starting at off, given the
   1254  *	old head and tail offsets *headp and *tailp, store the new head
   1255  *	and tail offsets in *headp and *tailp resulting from adding
   1256  *	delta bytes of data to the head.
   1257  */
   1258 static inline void
   1259 wapbl_advance_head(size_t size, size_t off, size_t delta, off_t *headp,
   1260 		   off_t *tailp)
   1261 {
   1262 	off_t head = *headp;
   1263 	off_t tail = *tailp;
   1264 
   1265 	KASSERT(delta <= wapbl_space_free(size, head, tail));
   1266 	head = wapbl_advance(size, off, head, delta);
   1267 	if ((tail == 0) && (head != 0))
   1268 		tail = off;
   1269 	*headp = head;
   1270 	*tailp = tail;
   1271 }
   1272 
   1273 /*
   1274  * wapbl_advance_tail(size, off, delta, headp, tailp)
   1275  *
   1276  *	In a circular queue of size bytes starting at off, given the
   1277  *	old head and tail offsets *headp and *tailp, store the new head
   1278  *	and tail offsets in *headp and *tailp resulting from removing
   1279  *	delta bytes of data from the tail.
   1280  */
   1281 static inline void
   1282 wapbl_advance_tail(size_t size, size_t off, size_t delta, off_t *headp,
   1283 		   off_t *tailp)
   1284 {
   1285 	off_t head = *headp;
   1286 	off_t tail = *tailp;
   1287 
   1288 	KASSERT(delta <= wapbl_space_used(size, head, tail));
   1289 	tail = wapbl_advance(size, off, tail, delta);
   1290 	if (head == tail) {
   1291 		head = tail = 0;
   1292 	}
   1293 	*headp = head;
   1294 	*tailp = tail;
   1295 }
   1296 
   1297 
   1298 /****************************************************************/
   1299 
   1300 /*
   1301  * wapbl_truncate(wl, minfree)
   1302  *
   1303  *	Wait until at least minfree bytes are available in the log.
   1304  *
   1305  *	If it was necessary to wait for writes to complete,
   1306  *	advance the circular queue tail to reflect the new write
   1307  *	completions and issue a write commit to the log.
   1308  *
   1309  *	=> Caller must hold wl->wl_rwlock writer lock.
   1310  */
   1311 static int
   1312 wapbl_truncate(struct wapbl *wl, size_t minfree)
   1313 {
   1314 	size_t delta;
   1315 	size_t avail;
   1316 	off_t head;
   1317 	off_t tail;
   1318 	int error = 0;
   1319 
   1320 	KASSERT(minfree <= (wl->wl_circ_size - wl->wl_reserved_bytes));
   1321 	KASSERT(rw_write_held(&wl->wl_rwlock));
   1322 
   1323 	mutex_enter(&wl->wl_mtx);
   1324 
   1325 	/*
   1326 	 * First check to see if we have to do a commit
   1327 	 * at all.
   1328 	 */
   1329 	avail = wapbl_space_free(wl->wl_circ_size, wl->wl_head, wl->wl_tail);
   1330 	if (minfree < avail) {
   1331 		mutex_exit(&wl->wl_mtx);
   1332 		return 0;
   1333 	}
   1334 	minfree -= avail;
   1335 	while ((wl->wl_error_count == 0) &&
   1336 	    (wl->wl_reclaimable_bytes < minfree)) {
   1337         	WAPBL_PRINTF(WAPBL_PRINT_TRUNCATE,
   1338                    ("wapbl_truncate: sleeping on %p wl=%p bytes=%zd "
   1339 		    "minfree=%zd\n",
   1340                     &wl->wl_reclaimable_bytes, wl, wl->wl_reclaimable_bytes,
   1341 		    minfree));
   1342 
   1343 		cv_wait(&wl->wl_reclaimable_cv, &wl->wl_mtx);
   1344 	}
   1345 	if (wl->wl_reclaimable_bytes < minfree) {
   1346 		KASSERT(wl->wl_error_count);
   1347 		/* XXX maybe get actual error from buffer instead someday? */
   1348 		error = EIO;
   1349 	}
   1350 	head = wl->wl_head;
   1351 	tail = wl->wl_tail;
   1352 	delta = wl->wl_reclaimable_bytes;
   1353 
   1354 	/* If all of of the entries are flushed, then be sure to keep
   1355 	 * the reserved bytes reserved.  Watch out for discarded transactions,
   1356 	 * which could leave more bytes reserved than are reclaimable.
   1357 	 */
   1358 	if (SIMPLEQ_EMPTY(&wl->wl_entries) &&
   1359 	    (delta >= wl->wl_reserved_bytes)) {
   1360 		delta -= wl->wl_reserved_bytes;
   1361 	}
   1362 	wapbl_advance_tail(wl->wl_circ_size, wl->wl_circ_off, delta, &head,
   1363 			   &tail);
   1364 	KDASSERT(wl->wl_reserved_bytes <=
   1365 		wapbl_space_used(wl->wl_circ_size, head, tail));
   1366 	mutex_exit(&wl->wl_mtx);
   1367 
   1368 	if (error)
   1369 		return error;
   1370 
   1371 	/*
   1372 	 * This is where head, tail and delta are unprotected
   1373 	 * from races against itself or flush.  This is ok since
   1374 	 * we only call this routine from inside flush itself.
   1375 	 *
   1376 	 * XXX: how can it race against itself when accessed only
   1377 	 * from behind the write-locked rwlock?
   1378 	 */
   1379 	error = wapbl_write_commit(wl, head, tail);
   1380 	if (error)
   1381 		return error;
   1382 
   1383 	wl->wl_head = head;
   1384 	wl->wl_tail = tail;
   1385 
   1386 	mutex_enter(&wl->wl_mtx);
   1387 	KASSERT(wl->wl_reclaimable_bytes >= delta);
   1388 	wl->wl_reclaimable_bytes -= delta;
   1389 	mutex_exit(&wl->wl_mtx);
   1390 	WAPBL_PRINTF(WAPBL_PRINT_TRUNCATE,
   1391 	    ("wapbl_truncate thread %d.%d truncating %zu bytes\n",
   1392 	    curproc->p_pid, curlwp->l_lid, delta));
   1393 
   1394 	return 0;
   1395 }
   1396 
   1397 /****************************************************************/
   1398 
   1399 void
   1400 wapbl_biodone(struct buf *bp)
   1401 {
   1402 	struct wapbl_entry *we = bp->b_private;
   1403 	struct wapbl *wl = we->we_wapbl;
   1404 #ifdef WAPBL_DEBUG_BUFBYTES
   1405 	const int bufsize = bp->b_bufsize;
   1406 #endif
   1407 
   1408 	/*
   1409 	 * Handle possible flushing of buffers after log has been
   1410 	 * decomissioned.
   1411 	 */
   1412 	if (!wl) {
   1413 		KASSERT(we->we_bufcount > 0);
   1414 		we->we_bufcount--;
   1415 #ifdef WAPBL_DEBUG_BUFBYTES
   1416 		KASSERT(we->we_unsynced_bufbytes >= bufsize);
   1417 		we->we_unsynced_bufbytes -= bufsize;
   1418 #endif
   1419 
   1420 		if (we->we_bufcount == 0) {
   1421 #ifdef WAPBL_DEBUG_BUFBYTES
   1422 			KASSERT(we->we_unsynced_bufbytes == 0);
   1423 #endif
   1424 			pool_put(&wapbl_entry_pool, we);
   1425 		}
   1426 
   1427 		brelse(bp, 0);
   1428 		return;
   1429 	}
   1430 
   1431 #ifdef ohbother
   1432 	KDASSERT(bp->b_oflags & BO_DONE);
   1433 	KDASSERT(!(bp->b_oflags & BO_DELWRI));
   1434 	KDASSERT(bp->b_flags & B_ASYNC);
   1435 	KDASSERT(bp->b_cflags & BC_BUSY);
   1436 	KDASSERT(!(bp->b_flags & B_LOCKED));
   1437 	KDASSERT(!(bp->b_flags & B_READ));
   1438 	KDASSERT(!(bp->b_cflags & BC_INVAL));
   1439 	KDASSERT(!(bp->b_cflags & BC_NOCACHE));
   1440 #endif
   1441 
   1442 	if (bp->b_error) {
   1443 		/*
   1444 		 * If an error occurs, it would be nice to leave the buffer
   1445 		 * as a delayed write on the LRU queue so that we can retry
   1446 		 * it later. But buffercache(9) can't handle dirty buffer
   1447 		 * reuse, so just mark the log permanently errored out.
   1448 		 */
   1449 		mutex_enter(&wl->wl_mtx);
   1450 		if (wl->wl_error_count == 0) {
   1451 			wl->wl_error_count++;
   1452 			cv_broadcast(&wl->wl_reclaimable_cv);
   1453 		}
   1454 		mutex_exit(&wl->wl_mtx);
   1455 	}
   1456 
   1457 	/*
   1458 	 * Release the buffer here. wapbl_flush() may wait for the
   1459 	 * log to become empty and we better unbusy the buffer before
   1460 	 * wapbl_flush() returns.
   1461 	 */
   1462 	brelse(bp, 0);
   1463 
   1464 	mutex_enter(&wl->wl_mtx);
   1465 
   1466 	KASSERT(we->we_bufcount > 0);
   1467 	we->we_bufcount--;
   1468 #ifdef WAPBL_DEBUG_BUFBYTES
   1469 	KASSERT(we->we_unsynced_bufbytes >= bufsize);
   1470 	we->we_unsynced_bufbytes -= bufsize;
   1471 	KASSERT(wl->wl_unsynced_bufbytes >= bufsize);
   1472 	wl->wl_unsynced_bufbytes -= bufsize;
   1473 #endif
   1474 
   1475 	/*
   1476 	 * If the current transaction can be reclaimed, start
   1477 	 * at the beginning and reclaim any consecutive reclaimable
   1478 	 * transactions.  If we successfully reclaim anything,
   1479 	 * then wakeup anyone waiting for the reclaim.
   1480 	 */
   1481 	if (we->we_bufcount == 0) {
   1482 		size_t delta = 0;
   1483 		int errcnt = 0;
   1484 #ifdef WAPBL_DEBUG_BUFBYTES
   1485 		KDASSERT(we->we_unsynced_bufbytes == 0);
   1486 #endif
   1487 		/*
   1488 		 * clear any posted error, since the buffer it came from
   1489 		 * has successfully flushed by now
   1490 		 */
   1491 		while ((we = SIMPLEQ_FIRST(&wl->wl_entries)) &&
   1492 		       (we->we_bufcount == 0)) {
   1493 			delta += we->we_reclaimable_bytes;
   1494 			if (we->we_error)
   1495 				errcnt++;
   1496 			SIMPLEQ_REMOVE_HEAD(&wl->wl_entries, we_entries);
   1497 			pool_put(&wapbl_entry_pool, we);
   1498 		}
   1499 
   1500 		if (delta) {
   1501 			wl->wl_reclaimable_bytes += delta;
   1502 			KASSERT(wl->wl_error_count >= errcnt);
   1503 			wl->wl_error_count -= errcnt;
   1504 			cv_broadcast(&wl->wl_reclaimable_cv);
   1505 		}
   1506 	}
   1507 
   1508 	mutex_exit(&wl->wl_mtx);
   1509 }
   1510 
   1511 /*
   1512  * wapbl_flush(wl, wait)
   1513  *
   1514  *	Flush pending block writes, deallocations, and inodes from
   1515  *	the current transaction in memory to the log on disk:
   1516  *
   1517  *	1. Call the file system's wl_flush callback to flush any
   1518  *	   per-file-system pending updates.
   1519  *	2. Wait for enough space in the log for the current transaction.
   1520  *	3. Synchronously write the new log records, advancing the
   1521  *	   circular queue head.
   1522  *	4. Issue the pending block writes asynchronously, now that they
   1523  *	   are recorded in the log and can be replayed after crash.
   1524  *	5. If wait is true, wait for all writes to complete and for the
   1525  *	   log to become empty.
   1526  *
   1527  *	On failure, call the file system's wl_flush_abort callback.
   1528  */
   1529 int
   1530 wapbl_flush(struct wapbl *wl, int waitfor)
   1531 {
   1532 	struct buf *bp;
   1533 	struct wapbl_entry *we;
   1534 	off_t off;
   1535 	off_t head;
   1536 	off_t tail;
   1537 	size_t delta = 0;
   1538 	size_t flushsize;
   1539 	size_t reserved;
   1540 	int error = 0;
   1541 
   1542 	/*
   1543 	 * Do a quick check to see if a full flush can be skipped
   1544 	 * This assumes that the flush callback does not need to be called
   1545 	 * unless there are other outstanding bufs.
   1546 	 */
   1547 	if (!waitfor) {
   1548 		size_t nbufs;
   1549 		mutex_enter(&wl->wl_mtx);	/* XXX need mutex here to
   1550 						   protect the KASSERTS */
   1551 		nbufs = wl->wl_bufcount;
   1552 		KASSERT((wl->wl_bufcount == 0) == (wl->wl_bufbytes == 0));
   1553 		KASSERT((wl->wl_bufcount == 0) == (wl->wl_bcount == 0));
   1554 		mutex_exit(&wl->wl_mtx);
   1555 		if (nbufs == 0)
   1556 			return 0;
   1557 	}
   1558 
   1559 	/*
   1560 	 * XXX we may consider using LK_UPGRADE here
   1561 	 * if we want to call flush from inside a transaction
   1562 	 */
   1563 	rw_enter(&wl->wl_rwlock, RW_WRITER);
   1564 	wl->wl_flush(wl->wl_mount, TAILQ_FIRST(&wl->wl_dealloclist));
   1565 
   1566 	/*
   1567 	 * Now that we are exclusively locked and the file system has
   1568 	 * issued any deferred block writes for this transaction, check
   1569 	 * whether there are any blocks to write to the log.  If not,
   1570 	 * skip waiting for space or writing any log entries.
   1571 	 *
   1572 	 * XXX Shouldn't this also check wl_dealloccnt and
   1573 	 * wl_inohashcnt?  Perhaps wl_dealloccnt doesn't matter if the
   1574 	 * file system didn't produce any blocks as a consequence of
   1575 	 * it, but the same does not seem to be so of wl_inohashcnt.
   1576 	 */
   1577 	if (wl->wl_bufcount == 0) {
   1578 		goto wait_out;
   1579 	}
   1580 
   1581 #if 0
   1582 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
   1583 		     ("wapbl_flush thread %d.%d flushing entries with "
   1584 		      "bufcount=%zu bufbytes=%zu\n",
   1585 		      curproc->p_pid, curlwp->l_lid, wl->wl_bufcount,
   1586 		      wl->wl_bufbytes));
   1587 #endif
   1588 
   1589 	/* Calculate amount of space needed to flush */
   1590 	flushsize = wapbl_transaction_len(wl);
   1591 	if (wapbl_verbose_commit) {
   1592 		struct timespec ts;
   1593 		getnanotime(&ts);
   1594 		printf("%s: %lld.%09ld this transaction = %zu bytes\n",
   1595 		    __func__, (long long)ts.tv_sec,
   1596 		    (long)ts.tv_nsec, flushsize);
   1597 	}
   1598 
   1599 	if (flushsize > (wl->wl_circ_size - wl->wl_reserved_bytes)) {
   1600 		/*
   1601 		 * XXX this could be handled more gracefully, perhaps place
   1602 		 * only a partial transaction in the log and allow the
   1603 		 * remaining to flush without the protection of the journal.
   1604 		 */
   1605 		panic("wapbl_flush: current transaction too big to flush");
   1606 	}
   1607 
   1608 	error = wapbl_truncate(wl, flushsize);
   1609 	if (error)
   1610 		goto out;
   1611 
   1612 	off = wl->wl_head;
   1613 	KASSERT((off == 0) || (off >= wl->wl_circ_off));
   1614 	KASSERT((off == 0) || (off < wl->wl_circ_off + wl->wl_circ_size));
   1615 	error = wapbl_write_blocks(wl, &off);
   1616 	if (error)
   1617 		goto out;
   1618 	error = wapbl_write_revocations(wl, &off);
   1619 	if (error)
   1620 		goto out;
   1621 	error = wapbl_write_inodes(wl, &off);
   1622 	if (error)
   1623 		goto out;
   1624 
   1625 	reserved = 0;
   1626 	if (wl->wl_inohashcnt)
   1627 		reserved = wapbl_transaction_inodes_len(wl);
   1628 
   1629 	head = wl->wl_head;
   1630 	tail = wl->wl_tail;
   1631 
   1632 	wapbl_advance_head(wl->wl_circ_size, wl->wl_circ_off, flushsize,
   1633 	    &head, &tail);
   1634 
   1635 	KASSERTMSG(head == off,
   1636 	    "lost head! head=%"PRIdMAX" tail=%" PRIdMAX
   1637 	    " off=%"PRIdMAX" flush=%zu",
   1638 	    (intmax_t)head, (intmax_t)tail, (intmax_t)off,
   1639 	    flushsize);
   1640 
   1641 	/* Opportunistically move the tail forward if we can */
   1642 	mutex_enter(&wl->wl_mtx);
   1643 	delta = wl->wl_reclaimable_bytes;
   1644 	mutex_exit(&wl->wl_mtx);
   1645 	wapbl_advance_tail(wl->wl_circ_size, wl->wl_circ_off, delta,
   1646 	    &head, &tail);
   1647 
   1648 	error = wapbl_write_commit(wl, head, tail);
   1649 	if (error)
   1650 		goto out;
   1651 
   1652 	we = pool_get(&wapbl_entry_pool, PR_WAITOK);
   1653 
   1654 #ifdef WAPBL_DEBUG_BUFBYTES
   1655 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
   1656 		("wapbl_flush: thread %d.%d head+=%zu tail+=%zu used=%zu"
   1657 		 " unsynced=%zu"
   1658 		 "\n\tbufcount=%zu bufbytes=%zu bcount=%zu deallocs=%d "
   1659 		 "inodes=%d\n",
   1660 		 curproc->p_pid, curlwp->l_lid, flushsize, delta,
   1661 		 wapbl_space_used(wl->wl_circ_size, head, tail),
   1662 		 wl->wl_unsynced_bufbytes, wl->wl_bufcount,
   1663 		 wl->wl_bufbytes, wl->wl_bcount, wl->wl_dealloccnt,
   1664 		 wl->wl_inohashcnt));
   1665 #else
   1666 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
   1667 		("wapbl_flush: thread %d.%d head+=%zu tail+=%zu used=%zu"
   1668 		 "\n\tbufcount=%zu bufbytes=%zu bcount=%zu deallocs=%d "
   1669 		 "inodes=%d\n",
   1670 		 curproc->p_pid, curlwp->l_lid, flushsize, delta,
   1671 		 wapbl_space_used(wl->wl_circ_size, head, tail),
   1672 		 wl->wl_bufcount, wl->wl_bufbytes, wl->wl_bcount,
   1673 		 wl->wl_dealloccnt, wl->wl_inohashcnt));
   1674 #endif
   1675 
   1676 
   1677 	mutex_enter(&bufcache_lock);
   1678 	mutex_enter(&wl->wl_mtx);
   1679 
   1680 	wl->wl_reserved_bytes = reserved;
   1681 	wl->wl_head = head;
   1682 	wl->wl_tail = tail;
   1683 	KASSERT(wl->wl_reclaimable_bytes >= delta);
   1684 	wl->wl_reclaimable_bytes -= delta;
   1685 	KDASSERT(wl->wl_dealloccnt == 0);
   1686 #ifdef WAPBL_DEBUG_BUFBYTES
   1687 	wl->wl_unsynced_bufbytes += wl->wl_bufbytes;
   1688 #endif
   1689 
   1690 	we->we_wapbl = wl;
   1691 	we->we_bufcount = wl->wl_bufcount;
   1692 #ifdef WAPBL_DEBUG_BUFBYTES
   1693 	we->we_unsynced_bufbytes = wl->wl_bufbytes;
   1694 #endif
   1695 	we->we_reclaimable_bytes = flushsize;
   1696 	we->we_error = 0;
   1697 	SIMPLEQ_INSERT_TAIL(&wl->wl_entries, we, we_entries);
   1698 
   1699 	/*
   1700 	 * this flushes bufs in reverse order than they were queued
   1701 	 * it shouldn't matter, but if we care we could use TAILQ instead.
   1702 	 * XXX Note they will get put on the lru queue when they flush
   1703 	 * so we might actually want to change this to preserve order.
   1704 	 */
   1705 	while ((bp = LIST_FIRST(&wl->wl_bufs)) != NULL) {
   1706 		if (bbusy(bp, 0, 0, &wl->wl_mtx)) {
   1707 			continue;
   1708 		}
   1709 		bp->b_iodone = wapbl_biodone;
   1710 		bp->b_private = we;
   1711 		bremfree(bp);
   1712 		wapbl_remove_buf_locked(wl, bp);
   1713 		mutex_exit(&wl->wl_mtx);
   1714 		mutex_exit(&bufcache_lock);
   1715 		bawrite(bp);
   1716 		mutex_enter(&bufcache_lock);
   1717 		mutex_enter(&wl->wl_mtx);
   1718 	}
   1719 	mutex_exit(&wl->wl_mtx);
   1720 	mutex_exit(&bufcache_lock);
   1721 
   1722 #if 0
   1723 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
   1724 		     ("wapbl_flush thread %d.%d done flushing entries...\n",
   1725 		     curproc->p_pid, curlwp->l_lid));
   1726 #endif
   1727 
   1728  wait_out:
   1729 
   1730 	/*
   1731 	 * If the waitfor flag is set, don't return until everything is
   1732 	 * fully flushed and the on disk log is empty.
   1733 	 */
   1734 	if (waitfor) {
   1735 		error = wapbl_truncate(wl, wl->wl_circ_size -
   1736 			wl->wl_reserved_bytes);
   1737 	}
   1738 
   1739  out:
   1740 	if (error) {
   1741 		wl->wl_flush_abort(wl->wl_mount,
   1742 		    TAILQ_FIRST(&wl->wl_dealloclist));
   1743 	}
   1744 
   1745 #ifdef WAPBL_DEBUG_PRINT
   1746 	if (error) {
   1747 		pid_t pid = -1;
   1748 		lwpid_t lid = -1;
   1749 		if (curproc)
   1750 			pid = curproc->p_pid;
   1751 		if (curlwp)
   1752 			lid = curlwp->l_lid;
   1753 		mutex_enter(&wl->wl_mtx);
   1754 #ifdef WAPBL_DEBUG_BUFBYTES
   1755 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
   1756 		    ("wapbl_flush: thread %d.%d aborted flush: "
   1757 		    "error = %d\n"
   1758 		    "\tbufcount=%zu bufbytes=%zu bcount=%zu "
   1759 		    "deallocs=%d inodes=%d\n"
   1760 		    "\terrcnt = %d, reclaimable=%zu reserved=%zu "
   1761 		    "unsynced=%zu\n",
   1762 		    pid, lid, error, wl->wl_bufcount,
   1763 		    wl->wl_bufbytes, wl->wl_bcount,
   1764 		    wl->wl_dealloccnt, wl->wl_inohashcnt,
   1765 		    wl->wl_error_count, wl->wl_reclaimable_bytes,
   1766 		    wl->wl_reserved_bytes, wl->wl_unsynced_bufbytes));
   1767 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
   1768 			WAPBL_PRINTF(WAPBL_PRINT_ERROR,
   1769 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
   1770 			     "error = %d, unsynced = %zu\n",
   1771 			     we->we_bufcount, we->we_reclaimable_bytes,
   1772 			     we->we_error, we->we_unsynced_bufbytes));
   1773 		}
   1774 #else
   1775 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
   1776 		    ("wapbl_flush: thread %d.%d aborted flush: "
   1777 		     "error = %d\n"
   1778 		     "\tbufcount=%zu bufbytes=%zu bcount=%zu "
   1779 		     "deallocs=%d inodes=%d\n"
   1780 		     "\terrcnt = %d, reclaimable=%zu reserved=%zu\n",
   1781 		     pid, lid, error, wl->wl_bufcount,
   1782 		     wl->wl_bufbytes, wl->wl_bcount,
   1783 		     wl->wl_dealloccnt, wl->wl_inohashcnt,
   1784 		     wl->wl_error_count, wl->wl_reclaimable_bytes,
   1785 		     wl->wl_reserved_bytes));
   1786 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
   1787 			WAPBL_PRINTF(WAPBL_PRINT_ERROR,
   1788 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
   1789 			     "error = %d\n", we->we_bufcount,
   1790 			     we->we_reclaimable_bytes, we->we_error));
   1791 		}
   1792 #endif
   1793 		mutex_exit(&wl->wl_mtx);
   1794 	}
   1795 #endif
   1796 
   1797 	rw_exit(&wl->wl_rwlock);
   1798 	return error;
   1799 }
   1800 
   1801 /****************************************************************/
   1802 
   1803 void
   1804 wapbl_jlock_assert(struct wapbl *wl)
   1805 {
   1806 
   1807 	KASSERT(rw_lock_held(&wl->wl_rwlock));
   1808 }
   1809 
   1810 void
   1811 wapbl_junlock_assert(struct wapbl *wl)
   1812 {
   1813 
   1814 	KASSERT(!rw_write_held(&wl->wl_rwlock));
   1815 }
   1816 
   1817 /****************************************************************/
   1818 
   1819 /* locks missing */
   1820 void
   1821 wapbl_print(struct wapbl *wl,
   1822 		int full,
   1823 		void (*pr)(const char *, ...))
   1824 {
   1825 	struct buf *bp;
   1826 	struct wapbl_entry *we;
   1827 	(*pr)("wapbl %p", wl);
   1828 	(*pr)("\nlogvp = %p, devvp = %p, logpbn = %"PRId64"\n",
   1829 	      wl->wl_logvp, wl->wl_devvp, wl->wl_logpbn);
   1830 	(*pr)("circ = %zu, header = %zu, head = %"PRIdMAX" tail = %"PRIdMAX"\n",
   1831 	      wl->wl_circ_size, wl->wl_circ_off,
   1832 	      (intmax_t)wl->wl_head, (intmax_t)wl->wl_tail);
   1833 	(*pr)("fs_dev_bshift = %d, log_dev_bshift = %d\n",
   1834 	      wl->wl_log_dev_bshift, wl->wl_fs_dev_bshift);
   1835 #ifdef WAPBL_DEBUG_BUFBYTES
   1836 	(*pr)("bufcount = %zu, bufbytes = %zu bcount = %zu reclaimable = %zu "
   1837 	      "reserved = %zu errcnt = %d unsynced = %zu\n",
   1838 	      wl->wl_bufcount, wl->wl_bufbytes, wl->wl_bcount,
   1839 	      wl->wl_reclaimable_bytes, wl->wl_reserved_bytes,
   1840 				wl->wl_error_count, wl->wl_unsynced_bufbytes);
   1841 #else
   1842 	(*pr)("bufcount = %zu, bufbytes = %zu bcount = %zu reclaimable = %zu "
   1843 	      "reserved = %zu errcnt = %d\n", wl->wl_bufcount, wl->wl_bufbytes,
   1844 	      wl->wl_bcount, wl->wl_reclaimable_bytes, wl->wl_reserved_bytes,
   1845 				wl->wl_error_count);
   1846 #endif
   1847 	(*pr)("\tdealloccnt = %d, dealloclim = %d\n",
   1848 	      wl->wl_dealloccnt, wl->wl_dealloclim);
   1849 	(*pr)("\tinohashcnt = %d, inohashmask = 0x%08x\n",
   1850 	      wl->wl_inohashcnt, wl->wl_inohashmask);
   1851 	(*pr)("entries:\n");
   1852 	SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
   1853 #ifdef WAPBL_DEBUG_BUFBYTES
   1854 		(*pr)("\tbufcount = %zu, reclaimable = %zu, error = %d, "
   1855 		      "unsynced = %zu\n",
   1856 		      we->we_bufcount, we->we_reclaimable_bytes,
   1857 		      we->we_error, we->we_unsynced_bufbytes);
   1858 #else
   1859 		(*pr)("\tbufcount = %zu, reclaimable = %zu, error = %d\n",
   1860 		      we->we_bufcount, we->we_reclaimable_bytes, we->we_error);
   1861 #endif
   1862 	}
   1863 	if (full) {
   1864 		int cnt = 0;
   1865 		(*pr)("bufs =");
   1866 		LIST_FOREACH(bp, &wl->wl_bufs, b_wapbllist) {
   1867 			if (!LIST_NEXT(bp, b_wapbllist)) {
   1868 				(*pr)(" %p", bp);
   1869 			} else if ((++cnt % 6) == 0) {
   1870 				(*pr)(" %p,\n\t", bp);
   1871 			} else {
   1872 				(*pr)(" %p,", bp);
   1873 			}
   1874 		}
   1875 		(*pr)("\n");
   1876 
   1877 		(*pr)("dealloced blks = ");
   1878 		{
   1879 			struct wapbl_dealloc *wd;
   1880 			cnt = 0;
   1881 			TAILQ_FOREACH(wd, &wl->wl_dealloclist, wd_entries) {
   1882 				(*pr)(" %"PRId64":%d,",
   1883 				      wd->wd_blkno,
   1884 				      wd->wd_len);
   1885 				if ((++cnt % 4) == 0) {
   1886 					(*pr)("\n\t");
   1887 				}
   1888 			}
   1889 		}
   1890 		(*pr)("\n");
   1891 
   1892 		(*pr)("registered inodes = ");
   1893 		{
   1894 			int i;
   1895 			cnt = 0;
   1896 			for (i = 0; i <= wl->wl_inohashmask; i++) {
   1897 				struct wapbl_ino_head *wih;
   1898 				struct wapbl_ino *wi;
   1899 
   1900 				wih = &wl->wl_inohash[i];
   1901 				LIST_FOREACH(wi, wih, wi_hash) {
   1902 					if (wi->wi_ino == 0)
   1903 						continue;
   1904 					(*pr)(" %"PRIu64"/0%06"PRIo32",",
   1905 					    wi->wi_ino, wi->wi_mode);
   1906 					if ((++cnt % 4) == 0) {
   1907 						(*pr)("\n\t");
   1908 					}
   1909 				}
   1910 			}
   1911 			(*pr)("\n");
   1912 		}
   1913 	}
   1914 }
   1915 
   1916 #if defined(WAPBL_DEBUG) || defined(DDB)
   1917 void
   1918 wapbl_dump(struct wapbl *wl)
   1919 {
   1920 #if defined(WAPBL_DEBUG)
   1921 	if (!wl)
   1922 		wl = wapbl_debug_wl;
   1923 #endif
   1924 	if (!wl)
   1925 		return;
   1926 	wapbl_print(wl, 1, printf);
   1927 }
   1928 #endif
   1929 
   1930 /****************************************************************/
   1931 
   1932 int
   1933 wapbl_register_deallocation(struct wapbl *wl, daddr_t blk, int len, bool force,
   1934     void **cookiep)
   1935 {
   1936 	struct wapbl_dealloc *wd;
   1937 	int error = 0;
   1938 
   1939 	wapbl_jlock_assert(wl);
   1940 
   1941 	mutex_enter(&wl->wl_mtx);
   1942 
   1943 	if (__predict_false(wl->wl_dealloccnt >= wl->wl_dealloclim)) {
   1944 		if (!force) {
   1945 			error = EAGAIN;
   1946 			goto out;
   1947 		}
   1948 
   1949 		/*
   1950 		 * Forced registration can only be used when:
   1951 		 * 1) the caller can't cope with failure
   1952 		 * 2) the path can be triggered only bounded, small
   1953 		 *    times per transaction
   1954 		 * If this is not fullfilled, and the path would be triggered
   1955 		 * many times, this could overflow maximum transaction size
   1956 		 * and panic later.
   1957 		 */
   1958 		printf("%s: forced dealloc registration over limit: %d >= %d\n",
   1959 			wl->wl_mount->mnt_stat.f_mntonname,
   1960 			wl->wl_dealloccnt, wl->wl_dealloclim);
   1961 	}
   1962 
   1963 	wl->wl_dealloccnt++;
   1964 	mutex_exit(&wl->wl_mtx);
   1965 
   1966 	wd = pool_get(&wapbl_dealloc_pool, PR_WAITOK);
   1967 	wd->wd_blkno = blk;
   1968 	wd->wd_len = len;
   1969 
   1970 	mutex_enter(&wl->wl_mtx);
   1971 	TAILQ_INSERT_TAIL(&wl->wl_dealloclist, wd, wd_entries);
   1972 
   1973 	if (cookiep)
   1974 		*cookiep = wd;
   1975 
   1976  out:
   1977 	mutex_exit(&wl->wl_mtx);
   1978 
   1979 	WAPBL_PRINTF(WAPBL_PRINT_ALLOC,
   1980 	    ("wapbl_register_deallocation: blk=%"PRId64" len=%d error=%d\n",
   1981 	    blk, len, error));
   1982 
   1983 	return error;
   1984 }
   1985 
   1986 static void
   1987 wapbl_deallocation_free(struct wapbl *wl, struct wapbl_dealloc *wd,
   1988 	bool locked)
   1989 {
   1990 	KASSERT(!locked
   1991 	    || rw_lock_held(&wl->wl_rwlock) || mutex_owned(&wl->wl_mtx));
   1992 
   1993 	if (!locked)
   1994 		mutex_enter(&wl->wl_mtx);
   1995 
   1996 	TAILQ_REMOVE(&wl->wl_dealloclist, wd, wd_entries);
   1997 	wl->wl_dealloccnt--;
   1998 
   1999 	if (!locked)
   2000 		mutex_exit(&wl->wl_mtx);
   2001 
   2002 	pool_put(&wapbl_dealloc_pool, wd);
   2003 }
   2004 
   2005 void
   2006 wapbl_unregister_deallocation(struct wapbl *wl, void *cookie)
   2007 {
   2008 	KASSERT(cookie != NULL);
   2009 	wapbl_deallocation_free(wl, cookie, false);
   2010 }
   2011 
   2012 /****************************************************************/
   2013 
   2014 static void
   2015 wapbl_inodetrk_init(struct wapbl *wl, u_int size)
   2016 {
   2017 
   2018 	wl->wl_inohash = hashinit(size, HASH_LIST, true, &wl->wl_inohashmask);
   2019 	if (atomic_inc_uint_nv(&wapbl_ino_pool_refcount) == 1) {
   2020 		pool_init(&wapbl_ino_pool, sizeof(struct wapbl_ino), 0, 0, 0,
   2021 		    "wapblinopl", &pool_allocator_nointr, IPL_NONE);
   2022 	}
   2023 }
   2024 
   2025 static void
   2026 wapbl_inodetrk_free(struct wapbl *wl)
   2027 {
   2028 
   2029 	/* XXX this KASSERT needs locking/mutex analysis */
   2030 	KASSERT(wl->wl_inohashcnt == 0);
   2031 	hashdone(wl->wl_inohash, HASH_LIST, wl->wl_inohashmask);
   2032 	if (atomic_dec_uint_nv(&wapbl_ino_pool_refcount) == 0) {
   2033 		pool_destroy(&wapbl_ino_pool);
   2034 	}
   2035 }
   2036 
   2037 static struct wapbl_ino *
   2038 wapbl_inodetrk_get(struct wapbl *wl, ino_t ino)
   2039 {
   2040 	struct wapbl_ino_head *wih;
   2041 	struct wapbl_ino *wi;
   2042 
   2043 	KASSERT(mutex_owned(&wl->wl_mtx));
   2044 
   2045 	wih = &wl->wl_inohash[ino & wl->wl_inohashmask];
   2046 	LIST_FOREACH(wi, wih, wi_hash) {
   2047 		if (ino == wi->wi_ino)
   2048 			return wi;
   2049 	}
   2050 	return 0;
   2051 }
   2052 
   2053 void
   2054 wapbl_register_inode(struct wapbl *wl, ino_t ino, mode_t mode)
   2055 {
   2056 	struct wapbl_ino_head *wih;
   2057 	struct wapbl_ino *wi;
   2058 
   2059 	wi = pool_get(&wapbl_ino_pool, PR_WAITOK);
   2060 
   2061 	mutex_enter(&wl->wl_mtx);
   2062 	if (wapbl_inodetrk_get(wl, ino) == NULL) {
   2063 		wi->wi_ino = ino;
   2064 		wi->wi_mode = mode;
   2065 		wih = &wl->wl_inohash[ino & wl->wl_inohashmask];
   2066 		LIST_INSERT_HEAD(wih, wi, wi_hash);
   2067 		wl->wl_inohashcnt++;
   2068 		WAPBL_PRINTF(WAPBL_PRINT_INODE,
   2069 		    ("wapbl_register_inode: ino=%"PRId64"\n", ino));
   2070 		mutex_exit(&wl->wl_mtx);
   2071 	} else {
   2072 		mutex_exit(&wl->wl_mtx);
   2073 		pool_put(&wapbl_ino_pool, wi);
   2074 	}
   2075 }
   2076 
   2077 void
   2078 wapbl_unregister_inode(struct wapbl *wl, ino_t ino, mode_t mode)
   2079 {
   2080 	struct wapbl_ino *wi;
   2081 
   2082 	mutex_enter(&wl->wl_mtx);
   2083 	wi = wapbl_inodetrk_get(wl, ino);
   2084 	if (wi) {
   2085 		WAPBL_PRINTF(WAPBL_PRINT_INODE,
   2086 		    ("wapbl_unregister_inode: ino=%"PRId64"\n", ino));
   2087 		KASSERT(wl->wl_inohashcnt > 0);
   2088 		wl->wl_inohashcnt--;
   2089 		LIST_REMOVE(wi, wi_hash);
   2090 		mutex_exit(&wl->wl_mtx);
   2091 
   2092 		pool_put(&wapbl_ino_pool, wi);
   2093 	} else {
   2094 		mutex_exit(&wl->wl_mtx);
   2095 	}
   2096 }
   2097 
   2098 /****************************************************************/
   2099 
   2100 /*
   2101  * wapbl_transaction_inodes_len(wl)
   2102  *
   2103  *	Calculate the number of bytes required for inode registration
   2104  *	log records in wl.
   2105  */
   2106 static inline size_t
   2107 wapbl_transaction_inodes_len(struct wapbl *wl)
   2108 {
   2109 	int blocklen = 1<<wl->wl_log_dev_bshift;
   2110 	int iph;
   2111 
   2112 	/* Calculate number of inodes described in a inodelist header */
   2113 	iph = (blocklen - offsetof(struct wapbl_wc_inodelist, wc_inodes)) /
   2114 	    sizeof(((struct wapbl_wc_inodelist *)0)->wc_inodes[0]);
   2115 
   2116 	KASSERT(iph > 0);
   2117 
   2118 	return MAX(1, howmany(wl->wl_inohashcnt, iph)) * blocklen;
   2119 }
   2120 
   2121 
   2122 /*
   2123  * wapbl_transaction_len(wl)
   2124  *
   2125  *	Calculate number of bytes required for all log records in wl.
   2126  */
   2127 static size_t
   2128 wapbl_transaction_len(struct wapbl *wl)
   2129 {
   2130 	int blocklen = 1<<wl->wl_log_dev_bshift;
   2131 	size_t len;
   2132 
   2133 	/* Calculate number of blocks described in a blocklist header */
   2134 	len = wl->wl_bcount;
   2135 	len += howmany(wl->wl_bufcount, wl->wl_brperjblock) * blocklen;
   2136 	len += howmany(wl->wl_dealloccnt, wl->wl_brperjblock) * blocklen;
   2137 	len += wapbl_transaction_inodes_len(wl);
   2138 
   2139 	return len;
   2140 }
   2141 
   2142 /*
   2143  * wapbl_cache_sync(wl, msg)
   2144  *
   2145  *	Issue DIOCCACHESYNC to wl->wl_devvp.
   2146  *
   2147  *	If sysctl(vfs.wapbl.verbose_commit) >= 2, print a message
   2148  *	including msg about the duration of the cache sync.
   2149  */
   2150 static int
   2151 wapbl_cache_sync(struct wapbl *wl, const char *msg)
   2152 {
   2153 	const bool verbose = wapbl_verbose_commit >= 2;
   2154 	struct bintime start_time;
   2155 	int force = 1;
   2156 	int error;
   2157 
   2158 	if (!wapbl_flush_disk_cache) {
   2159 		return 0;
   2160 	}
   2161 	if (verbose) {
   2162 		bintime(&start_time);
   2163 	}
   2164 	error = VOP_IOCTL(wl->wl_devvp, DIOCCACHESYNC, &force,
   2165 	    FWRITE, FSCRED);
   2166 	if (error) {
   2167 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
   2168 		    ("wapbl_cache_sync: DIOCCACHESYNC on dev 0x%jx "
   2169 		    "returned %d\n", (uintmax_t)wl->wl_devvp->v_rdev, error));
   2170 	}
   2171 	if (verbose) {
   2172 		struct bintime d;
   2173 		struct timespec ts;
   2174 
   2175 		bintime(&d);
   2176 		bintime_sub(&d, &start_time);
   2177 		bintime2timespec(&d, &ts);
   2178 		printf("wapbl_cache_sync: %s: dev 0x%jx %ju.%09lu\n",
   2179 		    msg, (uintmax_t)wl->wl_devvp->v_rdev,
   2180 		    (uintmax_t)ts.tv_sec, ts.tv_nsec);
   2181 	}
   2182 	return error;
   2183 }
   2184 
   2185 /*
   2186  * wapbl_write_commit(wl, head, tail)
   2187  *
   2188  *	Issue a disk cache sync to wait for all pending writes to the
   2189  *	log to complete, and then synchronously commit the current
   2190  *	circular queue head and tail to the log, in the next of two
   2191  *	locations for commit headers on disk.
   2192  *
   2193  *	Increment the generation number.  If the generation number
   2194  *	rolls over to zero, then a subsequent commit would appear to
   2195  *	have an older generation than this one -- in that case, issue a
   2196  *	duplicate commit to avoid this.
   2197  *
   2198  *	=> Caller must have exclusive access to wl, either by holding
   2199  *	wl->wl_rwlock for writer or by being wapbl_start before anyone
   2200  *	else has seen wl.
   2201  */
   2202 static int
   2203 wapbl_write_commit(struct wapbl *wl, off_t head, off_t tail)
   2204 {
   2205 	struct wapbl_wc_header *wc = wl->wl_wc_header;
   2206 	struct timespec ts;
   2207 	int error;
   2208 	daddr_t pbn;
   2209 
   2210 	error = wapbl_buffered_flush(wl);
   2211 	if (error)
   2212 		return error;
   2213 	/*
   2214 	 * flush disk cache to ensure that blocks we've written are actually
   2215 	 * written to the stable storage before the commit header.
   2216 	 *
   2217 	 * XXX Calc checksum here, instead we do this for now
   2218 	 */
   2219 	wapbl_cache_sync(wl, "1");
   2220 
   2221 	wc->wc_head = head;
   2222 	wc->wc_tail = tail;
   2223 	wc->wc_checksum = 0;
   2224 	wc->wc_version = 1;
   2225 	getnanotime(&ts);
   2226 	wc->wc_time = ts.tv_sec;
   2227 	wc->wc_timensec = ts.tv_nsec;
   2228 
   2229 	WAPBL_PRINTF(WAPBL_PRINT_WRITE,
   2230 	    ("wapbl_write_commit: head = %"PRIdMAX "tail = %"PRIdMAX"\n",
   2231 	    (intmax_t)head, (intmax_t)tail));
   2232 
   2233 	/*
   2234 	 * write the commit header.
   2235 	 *
   2236 	 * XXX if generation will rollover, then first zero
   2237 	 * over second commit header before trying to write both headers.
   2238 	 */
   2239 
   2240 	pbn = wl->wl_logpbn + (wc->wc_generation % 2);
   2241 #ifdef _KERNEL
   2242 	pbn = btodb(pbn << wc->wc_log_dev_bshift);
   2243 #endif
   2244 	error = wapbl_buffered_write(wc, wc->wc_len, wl, pbn);
   2245 	if (error)
   2246 		return error;
   2247 	error = wapbl_buffered_flush(wl);
   2248 	if (error)
   2249 		return error;
   2250 
   2251 	/*
   2252 	 * flush disk cache to ensure that the commit header is actually
   2253 	 * written before meta data blocks.
   2254 	 */
   2255 	wapbl_cache_sync(wl, "2");
   2256 
   2257 	/*
   2258 	 * If the generation number was zero, write it out a second time.
   2259 	 * This handles initialization and generation number rollover
   2260 	 */
   2261 	if (wc->wc_generation++ == 0) {
   2262 		error = wapbl_write_commit(wl, head, tail);
   2263 		/*
   2264 		 * This panic should be able to be removed if we do the
   2265 		 * zero'ing mentioned above, and we are certain to roll
   2266 		 * back generation number on failure.
   2267 		 */
   2268 		if (error)
   2269 			panic("wapbl_write_commit: error writing duplicate "
   2270 			      "log header: %d", error);
   2271 	}
   2272 	return 0;
   2273 }
   2274 
   2275 /*
   2276  * wapbl_write_blocks(wl, offp)
   2277  *
   2278  *	Write all pending physical blocks in the current transaction
   2279  *	from wapbl_add_buf to the log on disk, adding to the circular
   2280  *	queue head at byte offset *offp, and returning the new head's
   2281  *	byte offset in *offp.
   2282  */
   2283 static int
   2284 wapbl_write_blocks(struct wapbl *wl, off_t *offp)
   2285 {
   2286 	struct wapbl_wc_blocklist *wc =
   2287 	    (struct wapbl_wc_blocklist *)wl->wl_wc_scratch;
   2288 	int blocklen = 1<<wl->wl_log_dev_bshift;
   2289 	struct buf *bp;
   2290 	off_t off = *offp;
   2291 	int error;
   2292 	size_t padding;
   2293 
   2294 	KASSERT(rw_write_held(&wl->wl_rwlock));
   2295 
   2296 	bp = LIST_FIRST(&wl->wl_bufs);
   2297 
   2298 	while (bp) {
   2299 		int cnt;
   2300 		struct buf *obp = bp;
   2301 
   2302 		KASSERT(bp->b_flags & B_LOCKED);
   2303 
   2304 		wc->wc_type = WAPBL_WC_BLOCKS;
   2305 		wc->wc_len = blocklen;
   2306 		wc->wc_blkcount = 0;
   2307 		while (bp && (wc->wc_blkcount < wl->wl_brperjblock)) {
   2308 			/*
   2309 			 * Make sure all the physical block numbers are up to
   2310 			 * date.  If this is not always true on a given
   2311 			 * filesystem, then VOP_BMAP must be called.  We
   2312 			 * could call VOP_BMAP here, or else in the filesystem
   2313 			 * specific flush callback, although neither of those
   2314 			 * solutions allow us to take the vnode lock.  If a
   2315 			 * filesystem requires that we must take the vnode lock
   2316 			 * to call VOP_BMAP, then we can probably do it in
   2317 			 * bwrite when the vnode lock should already be held
   2318 			 * by the invoking code.
   2319 			 */
   2320 			KASSERT((bp->b_vp->v_type == VBLK) ||
   2321 				 (bp->b_blkno != bp->b_lblkno));
   2322 			KASSERT(bp->b_blkno > 0);
   2323 
   2324 			wc->wc_blocks[wc->wc_blkcount].wc_daddr = bp->b_blkno;
   2325 			wc->wc_blocks[wc->wc_blkcount].wc_dlen = bp->b_bcount;
   2326 			wc->wc_len += bp->b_bcount;
   2327 			wc->wc_blkcount++;
   2328 			bp = LIST_NEXT(bp, b_wapbllist);
   2329 		}
   2330 		if (wc->wc_len % blocklen != 0) {
   2331 			padding = blocklen - wc->wc_len % blocklen;
   2332 			wc->wc_len += padding;
   2333 		} else {
   2334 			padding = 0;
   2335 		}
   2336 
   2337 		WAPBL_PRINTF(WAPBL_PRINT_WRITE,
   2338 		    ("wapbl_write_blocks: len = %u (padding %zu) off = %"PRIdMAX"\n",
   2339 		    wc->wc_len, padding, (intmax_t)off));
   2340 
   2341 		error = wapbl_circ_write(wl, wc, blocklen, &off);
   2342 		if (error)
   2343 			return error;
   2344 		bp = obp;
   2345 		cnt = 0;
   2346 		while (bp && (cnt++ < wl->wl_brperjblock)) {
   2347 			error = wapbl_circ_write(wl, bp->b_data,
   2348 			    bp->b_bcount, &off);
   2349 			if (error)
   2350 				return error;
   2351 			bp = LIST_NEXT(bp, b_wapbllist);
   2352 		}
   2353 		if (padding) {
   2354 			void *zero;
   2355 
   2356 			zero = wapbl_alloc(padding);
   2357 			memset(zero, 0, padding);
   2358 			error = wapbl_circ_write(wl, zero, padding, &off);
   2359 			wapbl_free(zero, padding);
   2360 			if (error)
   2361 				return error;
   2362 		}
   2363 	}
   2364 	*offp = off;
   2365 	return 0;
   2366 }
   2367 
   2368 /*
   2369  * wapbl_write_revocations(wl, offp)
   2370  *
   2371  *	Write all pending deallocations in the current transaction from
   2372  *	wapbl_register_deallocation to the log on disk, adding to the
   2373  *	circular queue's head at byte offset *offp, and returning the
   2374  *	new head's byte offset in *offp.
   2375  */
   2376 static int
   2377 wapbl_write_revocations(struct wapbl *wl, off_t *offp)
   2378 {
   2379 	struct wapbl_wc_blocklist *wc =
   2380 	    (struct wapbl_wc_blocklist *)wl->wl_wc_scratch;
   2381 	struct wapbl_dealloc *wd, *lwd;
   2382 	int blocklen = 1<<wl->wl_log_dev_bshift;
   2383 	off_t off = *offp;
   2384 	int error;
   2385 
   2386 	if (wl->wl_dealloccnt == 0)
   2387 		return 0;
   2388 
   2389 	while ((wd = TAILQ_FIRST(&wl->wl_dealloclist)) != NULL) {
   2390 		wc->wc_type = WAPBL_WC_REVOCATIONS;
   2391 		wc->wc_len = blocklen;
   2392 		wc->wc_blkcount = 0;
   2393 		while (wd && (wc->wc_blkcount < wl->wl_brperjblock)) {
   2394 			wc->wc_blocks[wc->wc_blkcount].wc_daddr =
   2395 			    wd->wd_blkno;
   2396 			wc->wc_blocks[wc->wc_blkcount].wc_dlen =
   2397 			    wd->wd_len;
   2398 			wc->wc_blkcount++;
   2399 
   2400 			wd = TAILQ_NEXT(wd, wd_entries);
   2401 		}
   2402 		WAPBL_PRINTF(WAPBL_PRINT_WRITE,
   2403 		    ("wapbl_write_revocations: len = %u off = %"PRIdMAX"\n",
   2404 		    wc->wc_len, (intmax_t)off));
   2405 		error = wapbl_circ_write(wl, wc, blocklen, &off);
   2406 		if (error)
   2407 			return error;
   2408 
   2409 		/* free all successfully written deallocs */
   2410 		lwd = wd;
   2411 		while ((wd = TAILQ_FIRST(&wl->wl_dealloclist)) != NULL) {
   2412 			if (wd == lwd)
   2413 				break;
   2414 			wapbl_deallocation_free(wl, wd, true);
   2415 		}
   2416 	}
   2417 	*offp = off;
   2418 	return 0;
   2419 }
   2420 
   2421 /*
   2422  * wapbl_write_inodes(wl, offp)
   2423  *
   2424  *	Write all pending inode allocations in the current transaction
   2425  *	from wapbl_register_inode to the log on disk, adding to the
   2426  *	circular queue's head at byte offset *offp and returning the
   2427  *	new head's byte offset in *offp.
   2428  */
   2429 static int
   2430 wapbl_write_inodes(struct wapbl *wl, off_t *offp)
   2431 {
   2432 	struct wapbl_wc_inodelist *wc =
   2433 	    (struct wapbl_wc_inodelist *)wl->wl_wc_scratch;
   2434 	int i;
   2435 	int blocklen = 1 << wl->wl_log_dev_bshift;
   2436 	off_t off = *offp;
   2437 	int error;
   2438 
   2439 	struct wapbl_ino_head *wih;
   2440 	struct wapbl_ino *wi;
   2441 	int iph;
   2442 
   2443 	iph = (blocklen - offsetof(struct wapbl_wc_inodelist, wc_inodes)) /
   2444 	    sizeof(((struct wapbl_wc_inodelist *)0)->wc_inodes[0]);
   2445 
   2446 	i = 0;
   2447 	wih = &wl->wl_inohash[0];
   2448 	wi = 0;
   2449 	do {
   2450 		wc->wc_type = WAPBL_WC_INODES;
   2451 		wc->wc_len = blocklen;
   2452 		wc->wc_inocnt = 0;
   2453 		wc->wc_clear = (i == 0);
   2454 		while ((i < wl->wl_inohashcnt) && (wc->wc_inocnt < iph)) {
   2455 			while (!wi) {
   2456 				KASSERT((wih - &wl->wl_inohash[0])
   2457 				    <= wl->wl_inohashmask);
   2458 				wi = LIST_FIRST(wih++);
   2459 			}
   2460 			wc->wc_inodes[wc->wc_inocnt].wc_inumber = wi->wi_ino;
   2461 			wc->wc_inodes[wc->wc_inocnt].wc_imode = wi->wi_mode;
   2462 			wc->wc_inocnt++;
   2463 			i++;
   2464 			wi = LIST_NEXT(wi, wi_hash);
   2465 		}
   2466 		WAPBL_PRINTF(WAPBL_PRINT_WRITE,
   2467 		    ("wapbl_write_inodes: len = %u off = %"PRIdMAX"\n",
   2468 		    wc->wc_len, (intmax_t)off));
   2469 		error = wapbl_circ_write(wl, wc, blocklen, &off);
   2470 		if (error)
   2471 			return error;
   2472 	} while (i < wl->wl_inohashcnt);
   2473 
   2474 	*offp = off;
   2475 	return 0;
   2476 }
   2477 
   2478 #endif /* _KERNEL */
   2479 
   2480 /****************************************************************/
   2481 
   2482 struct wapbl_blk {
   2483 	LIST_ENTRY(wapbl_blk) wb_hash;
   2484 	daddr_t wb_blk;
   2485 	off_t wb_off; /* Offset of this block in the log */
   2486 };
   2487 #define	WAPBL_BLKPOOL_MIN 83
   2488 
   2489 static void
   2490 wapbl_blkhash_init(struct wapbl_replay *wr, u_int size)
   2491 {
   2492 	if (size < WAPBL_BLKPOOL_MIN)
   2493 		size = WAPBL_BLKPOOL_MIN;
   2494 	KASSERT(wr->wr_blkhash == 0);
   2495 #ifdef _KERNEL
   2496 	wr->wr_blkhash = hashinit(size, HASH_LIST, true, &wr->wr_blkhashmask);
   2497 #else /* ! _KERNEL */
   2498 	/* Manually implement hashinit */
   2499 	{
   2500 		unsigned long i, hashsize;
   2501 		for (hashsize = 1; hashsize < size; hashsize <<= 1)
   2502 			continue;
   2503 		wr->wr_blkhash = wapbl_alloc(hashsize * sizeof(*wr->wr_blkhash));
   2504 		for (i = 0; i < hashsize; i++)
   2505 			LIST_INIT(&wr->wr_blkhash[i]);
   2506 		wr->wr_blkhashmask = hashsize - 1;
   2507 	}
   2508 #endif /* ! _KERNEL */
   2509 }
   2510 
   2511 static void
   2512 wapbl_blkhash_free(struct wapbl_replay *wr)
   2513 {
   2514 	KASSERT(wr->wr_blkhashcnt == 0);
   2515 #ifdef _KERNEL
   2516 	hashdone(wr->wr_blkhash, HASH_LIST, wr->wr_blkhashmask);
   2517 #else /* ! _KERNEL */
   2518 	wapbl_free(wr->wr_blkhash,
   2519 	    (wr->wr_blkhashmask + 1) * sizeof(*wr->wr_blkhash));
   2520 #endif /* ! _KERNEL */
   2521 }
   2522 
   2523 static struct wapbl_blk *
   2524 wapbl_blkhash_get(struct wapbl_replay *wr, daddr_t blk)
   2525 {
   2526 	struct wapbl_blk_head *wbh;
   2527 	struct wapbl_blk *wb;
   2528 	wbh = &wr->wr_blkhash[blk & wr->wr_blkhashmask];
   2529 	LIST_FOREACH(wb, wbh, wb_hash) {
   2530 		if (blk == wb->wb_blk)
   2531 			return wb;
   2532 	}
   2533 	return 0;
   2534 }
   2535 
   2536 static void
   2537 wapbl_blkhash_ins(struct wapbl_replay *wr, daddr_t blk, off_t off)
   2538 {
   2539 	struct wapbl_blk_head *wbh;
   2540 	struct wapbl_blk *wb;
   2541 	wb = wapbl_blkhash_get(wr, blk);
   2542 	if (wb) {
   2543 		KASSERT(wb->wb_blk == blk);
   2544 		wb->wb_off = off;
   2545 	} else {
   2546 		wb = wapbl_alloc(sizeof(*wb));
   2547 		wb->wb_blk = blk;
   2548 		wb->wb_off = off;
   2549 		wbh = &wr->wr_blkhash[blk & wr->wr_blkhashmask];
   2550 		LIST_INSERT_HEAD(wbh, wb, wb_hash);
   2551 		wr->wr_blkhashcnt++;
   2552 	}
   2553 }
   2554 
   2555 static void
   2556 wapbl_blkhash_rem(struct wapbl_replay *wr, daddr_t blk)
   2557 {
   2558 	struct wapbl_blk *wb = wapbl_blkhash_get(wr, blk);
   2559 	if (wb) {
   2560 		KASSERT(wr->wr_blkhashcnt > 0);
   2561 		wr->wr_blkhashcnt--;
   2562 		LIST_REMOVE(wb, wb_hash);
   2563 		wapbl_free(wb, sizeof(*wb));
   2564 	}
   2565 }
   2566 
   2567 static void
   2568 wapbl_blkhash_clear(struct wapbl_replay *wr)
   2569 {
   2570 	unsigned long i;
   2571 	for (i = 0; i <= wr->wr_blkhashmask; i++) {
   2572 		struct wapbl_blk *wb;
   2573 
   2574 		while ((wb = LIST_FIRST(&wr->wr_blkhash[i]))) {
   2575 			KASSERT(wr->wr_blkhashcnt > 0);
   2576 			wr->wr_blkhashcnt--;
   2577 			LIST_REMOVE(wb, wb_hash);
   2578 			wapbl_free(wb, sizeof(*wb));
   2579 		}
   2580 	}
   2581 	KASSERT(wr->wr_blkhashcnt == 0);
   2582 }
   2583 
   2584 /****************************************************************/
   2585 
   2586 /*
   2587  * wapbl_circ_read(wr, data, len, offp)
   2588  *
   2589  *	Read len bytes into data from the circular queue of wr,
   2590  *	starting at the linear byte offset *offp, and returning the new
   2591  *	linear byte offset in *offp.
   2592  *
   2593  *	If the starting linear byte offset precedes wr->wr_circ_off,
   2594  *	the read instead begins at wr->wr_circ_off.  XXX WTF?  This
   2595  *	should be a KASSERT, not a conditional.
   2596  */
   2597 static int
   2598 wapbl_circ_read(struct wapbl_replay *wr, void *data, size_t len, off_t *offp)
   2599 {
   2600 	size_t slen;
   2601 	off_t off = *offp;
   2602 	int error;
   2603 	daddr_t pbn;
   2604 
   2605 	KASSERT(((len >> wr->wr_log_dev_bshift) <<
   2606 	    wr->wr_log_dev_bshift) == len);
   2607 
   2608 	if (off < wr->wr_circ_off)
   2609 		off = wr->wr_circ_off;
   2610 	slen = wr->wr_circ_off + wr->wr_circ_size - off;
   2611 	if (slen < len) {
   2612 		pbn = wr->wr_logpbn + (off >> wr->wr_log_dev_bshift);
   2613 #ifdef _KERNEL
   2614 		pbn = btodb(pbn << wr->wr_log_dev_bshift);
   2615 #endif
   2616 		error = wapbl_read(data, slen, wr->wr_devvp, pbn);
   2617 		if (error)
   2618 			return error;
   2619 		data = (uint8_t *)data + slen;
   2620 		len -= slen;
   2621 		off = wr->wr_circ_off;
   2622 	}
   2623 	pbn = wr->wr_logpbn + (off >> wr->wr_log_dev_bshift);
   2624 #ifdef _KERNEL
   2625 	pbn = btodb(pbn << wr->wr_log_dev_bshift);
   2626 #endif
   2627 	error = wapbl_read(data, len, wr->wr_devvp, pbn);
   2628 	if (error)
   2629 		return error;
   2630 	off += len;
   2631 	if (off >= wr->wr_circ_off + wr->wr_circ_size)
   2632 		off = wr->wr_circ_off;
   2633 	*offp = off;
   2634 	return 0;
   2635 }
   2636 
   2637 /*
   2638  * wapbl_circ_advance(wr, len, offp)
   2639  *
   2640  *	Compute the linear byte offset of the circular queue of wr that
   2641  *	is len bytes past *offp, and store it in *offp.
   2642  *
   2643  *	This is as if wapbl_circ_read, but without actually reading
   2644  *	anything.
   2645  *
   2646  *	If the starting linear byte offset precedes wr->wr_circ_off, it
   2647  *	is taken to be wr->wr_circ_off instead.  XXX WTF?  This should
   2648  *	be a KASSERT, not a conditional.
   2649  */
   2650 static void
   2651 wapbl_circ_advance(struct wapbl_replay *wr, size_t len, off_t *offp)
   2652 {
   2653 	size_t slen;
   2654 	off_t off = *offp;
   2655 
   2656 	KASSERT(((len >> wr->wr_log_dev_bshift) <<
   2657 	    wr->wr_log_dev_bshift) == len);
   2658 
   2659 	if (off < wr->wr_circ_off)
   2660 		off = wr->wr_circ_off;
   2661 	slen = wr->wr_circ_off + wr->wr_circ_size - off;
   2662 	if (slen < len) {
   2663 		len -= slen;
   2664 		off = wr->wr_circ_off;
   2665 	}
   2666 	off += len;
   2667 	if (off >= wr->wr_circ_off + wr->wr_circ_size)
   2668 		off = wr->wr_circ_off;
   2669 	*offp = off;
   2670 }
   2671 
   2672 /****************************************************************/
   2673 
   2674 int
   2675 wapbl_replay_start(struct wapbl_replay **wrp, struct vnode *vp,
   2676 	daddr_t off, size_t count, size_t blksize)
   2677 {
   2678 	struct wapbl_replay *wr;
   2679 	int error;
   2680 	struct vnode *devvp;
   2681 	daddr_t logpbn;
   2682 	uint8_t *scratch;
   2683 	struct wapbl_wc_header *wch;
   2684 	struct wapbl_wc_header *wch2;
   2685 	/* Use this until we read the actual log header */
   2686 	int log_dev_bshift = ilog2(blksize);
   2687 	size_t used;
   2688 	daddr_t pbn;
   2689 
   2690 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY,
   2691 	    ("wapbl_replay_start: vp=%p off=%"PRId64 " count=%zu blksize=%zu\n",
   2692 	    vp, off, count, blksize));
   2693 
   2694 	if (off < 0)
   2695 		return EINVAL;
   2696 
   2697 	if (blksize < DEV_BSIZE)
   2698 		return EINVAL;
   2699 	if (blksize % DEV_BSIZE)
   2700 		return EINVAL;
   2701 
   2702 #ifdef _KERNEL
   2703 #if 0
   2704 	/* XXX vp->v_size isn't reliably set for VBLK devices,
   2705 	 * especially root.  However, we might still want to verify
   2706 	 * that the full load is readable */
   2707 	if ((off + count) * blksize > vp->v_size)
   2708 		return EINVAL;
   2709 #endif
   2710 	if ((error = VOP_BMAP(vp, off, &devvp, &logpbn, 0)) != 0) {
   2711 		return error;
   2712 	}
   2713 #else /* ! _KERNEL */
   2714 	devvp = vp;
   2715 	logpbn = off;
   2716 #endif /* ! _KERNEL */
   2717 
   2718 	scratch = wapbl_alloc(MAXBSIZE);
   2719 
   2720 	pbn = logpbn;
   2721 #ifdef _KERNEL
   2722 	pbn = btodb(pbn << log_dev_bshift);
   2723 #endif
   2724 	error = wapbl_read(scratch, 2<<log_dev_bshift, devvp, pbn);
   2725 	if (error)
   2726 		goto errout;
   2727 
   2728 	wch = (struct wapbl_wc_header *)scratch;
   2729 	wch2 =
   2730 	    (struct wapbl_wc_header *)(scratch + (1<<log_dev_bshift));
   2731 	/* XXX verify checksums and magic numbers */
   2732 	if (wch->wc_type != WAPBL_WC_HEADER) {
   2733 		printf("Unrecognized wapbl magic: 0x%08x\n", wch->wc_type);
   2734 		error = EFTYPE;
   2735 		goto errout;
   2736 	}
   2737 
   2738 	if (wch2->wc_generation > wch->wc_generation)
   2739 		wch = wch2;
   2740 
   2741 	wr = wapbl_calloc(1, sizeof(*wr));
   2742 
   2743 	wr->wr_logvp = vp;
   2744 	wr->wr_devvp = devvp;
   2745 	wr->wr_logpbn = logpbn;
   2746 
   2747 	wr->wr_scratch = scratch;
   2748 
   2749 	wr->wr_log_dev_bshift = wch->wc_log_dev_bshift;
   2750 	wr->wr_fs_dev_bshift = wch->wc_fs_dev_bshift;
   2751 	wr->wr_circ_off = wch->wc_circ_off;
   2752 	wr->wr_circ_size = wch->wc_circ_size;
   2753 	wr->wr_generation = wch->wc_generation;
   2754 
   2755 	used = wapbl_space_used(wch->wc_circ_size, wch->wc_head, wch->wc_tail);
   2756 
   2757 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY,
   2758 	    ("wapbl_replay: head=%"PRId64" tail=%"PRId64" off=%"PRId64
   2759 	    " len=%"PRId64" used=%zu\n",
   2760 	    wch->wc_head, wch->wc_tail, wch->wc_circ_off,
   2761 	    wch->wc_circ_size, used));
   2762 
   2763 	wapbl_blkhash_init(wr, (used >> wch->wc_fs_dev_bshift));
   2764 
   2765 	error = wapbl_replay_process(wr, wch->wc_head, wch->wc_tail);
   2766 	if (error) {
   2767 		wapbl_replay_stop(wr);
   2768 		wapbl_replay_free(wr);
   2769 		return error;
   2770 	}
   2771 
   2772 	*wrp = wr;
   2773 	return 0;
   2774 
   2775  errout:
   2776 	wapbl_free(scratch, MAXBSIZE);
   2777 	return error;
   2778 }
   2779 
   2780 void
   2781 wapbl_replay_stop(struct wapbl_replay *wr)
   2782 {
   2783 
   2784 	if (!wapbl_replay_isopen(wr))
   2785 		return;
   2786 
   2787 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY, ("wapbl_replay_stop called\n"));
   2788 
   2789 	wapbl_free(wr->wr_scratch, MAXBSIZE);
   2790 	wr->wr_scratch = NULL;
   2791 
   2792 	wr->wr_logvp = NULL;
   2793 
   2794 	wapbl_blkhash_clear(wr);
   2795 	wapbl_blkhash_free(wr);
   2796 }
   2797 
   2798 void
   2799 wapbl_replay_free(struct wapbl_replay *wr)
   2800 {
   2801 
   2802 	KDASSERT(!wapbl_replay_isopen(wr));
   2803 
   2804 	if (wr->wr_inodes)
   2805 		wapbl_free(wr->wr_inodes,
   2806 		    wr->wr_inodescnt * sizeof(wr->wr_inodes[0]));
   2807 	wapbl_free(wr, sizeof(*wr));
   2808 }
   2809 
   2810 #ifdef _KERNEL
   2811 int
   2812 wapbl_replay_isopen1(struct wapbl_replay *wr)
   2813 {
   2814 
   2815 	return wapbl_replay_isopen(wr);
   2816 }
   2817 #endif
   2818 
   2819 /*
   2820  * calculate the disk address for the i'th block in the wc_blockblist
   2821  * offset by j blocks of size blen.
   2822  *
   2823  * wc_daddr is always a kernel disk address in DEV_BSIZE units that
   2824  * was written to the journal.
   2825  *
   2826  * The kernel needs that address plus the offset in DEV_BSIZE units.
   2827  *
   2828  * Userland needs that address plus the offset in blen units.
   2829  *
   2830  */
   2831 static daddr_t
   2832 wapbl_block_daddr(struct wapbl_wc_blocklist *wc, int i, int j, int blen)
   2833 {
   2834 	daddr_t pbn;
   2835 
   2836 #ifdef _KERNEL
   2837 	pbn = wc->wc_blocks[i].wc_daddr + btodb(j * blen);
   2838 #else
   2839 	pbn = dbtob(wc->wc_blocks[i].wc_daddr) / blen + j;
   2840 #endif
   2841 
   2842 	return pbn;
   2843 }
   2844 
   2845 static void
   2846 wapbl_replay_process_blocks(struct wapbl_replay *wr, off_t *offp)
   2847 {
   2848 	struct wapbl_wc_blocklist *wc =
   2849 	    (struct wapbl_wc_blocklist *)wr->wr_scratch;
   2850 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   2851 	int i, j, n;
   2852 
   2853 	for (i = 0; i < wc->wc_blkcount; i++) {
   2854 		/*
   2855 		 * Enter each physical block into the hashtable independently.
   2856 		 */
   2857 		n = wc->wc_blocks[i].wc_dlen >> wr->wr_fs_dev_bshift;
   2858 		for (j = 0; j < n; j++) {
   2859 			wapbl_blkhash_ins(wr, wapbl_block_daddr(wc, i, j, fsblklen),
   2860 			    *offp);
   2861 			wapbl_circ_advance(wr, fsblklen, offp);
   2862 		}
   2863 	}
   2864 }
   2865 
   2866 static void
   2867 wapbl_replay_process_revocations(struct wapbl_replay *wr)
   2868 {
   2869 	struct wapbl_wc_blocklist *wc =
   2870 	    (struct wapbl_wc_blocklist *)wr->wr_scratch;
   2871 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   2872 	int i, j, n;
   2873 
   2874 	for (i = 0; i < wc->wc_blkcount; i++) {
   2875 		/*
   2876 		 * Remove any blocks found from the hashtable.
   2877 		 */
   2878 		n = wc->wc_blocks[i].wc_dlen >> wr->wr_fs_dev_bshift;
   2879 		for (j = 0; j < n; j++)
   2880 			wapbl_blkhash_rem(wr, wapbl_block_daddr(wc, i, j, fsblklen));
   2881 	}
   2882 }
   2883 
   2884 static void
   2885 wapbl_replay_process_inodes(struct wapbl_replay *wr, off_t oldoff, off_t newoff)
   2886 {
   2887 	struct wapbl_wc_inodelist *wc =
   2888 	    (struct wapbl_wc_inodelist *)wr->wr_scratch;
   2889 	void *new_inodes;
   2890 	const size_t oldsize = wr->wr_inodescnt * sizeof(wr->wr_inodes[0]);
   2891 
   2892 	KASSERT(sizeof(wr->wr_inodes[0]) == sizeof(wc->wc_inodes[0]));
   2893 
   2894 	/*
   2895 	 * Keep track of where we found this so location won't be
   2896 	 * overwritten.
   2897 	 */
   2898 	if (wc->wc_clear) {
   2899 		wr->wr_inodestail = oldoff;
   2900 		wr->wr_inodescnt = 0;
   2901 		if (wr->wr_inodes != NULL) {
   2902 			wapbl_free(wr->wr_inodes, oldsize);
   2903 			wr->wr_inodes = NULL;
   2904 		}
   2905 	}
   2906 	wr->wr_inodeshead = newoff;
   2907 	if (wc->wc_inocnt == 0)
   2908 		return;
   2909 
   2910 	new_inodes = wapbl_alloc((wr->wr_inodescnt + wc->wc_inocnt) *
   2911 	    sizeof(wr->wr_inodes[0]));
   2912 	if (wr->wr_inodes != NULL) {
   2913 		memcpy(new_inodes, wr->wr_inodes, oldsize);
   2914 		wapbl_free(wr->wr_inodes, oldsize);
   2915 	}
   2916 	wr->wr_inodes = new_inodes;
   2917 	memcpy(&wr->wr_inodes[wr->wr_inodescnt], wc->wc_inodes,
   2918 	    wc->wc_inocnt * sizeof(wr->wr_inodes[0]));
   2919 	wr->wr_inodescnt += wc->wc_inocnt;
   2920 }
   2921 
   2922 static int
   2923 wapbl_replay_process(struct wapbl_replay *wr, off_t head, off_t tail)
   2924 {
   2925 	off_t off;
   2926 	int error;
   2927 
   2928 	int logblklen = 1 << wr->wr_log_dev_bshift;
   2929 
   2930 	wapbl_blkhash_clear(wr);
   2931 
   2932 	off = tail;
   2933 	while (off != head) {
   2934 		struct wapbl_wc_null *wcn;
   2935 		off_t saveoff = off;
   2936 		error = wapbl_circ_read(wr, wr->wr_scratch, logblklen, &off);
   2937 		if (error)
   2938 			goto errout;
   2939 		wcn = (struct wapbl_wc_null *)wr->wr_scratch;
   2940 		switch (wcn->wc_type) {
   2941 		case WAPBL_WC_BLOCKS:
   2942 			wapbl_replay_process_blocks(wr, &off);
   2943 			break;
   2944 
   2945 		case WAPBL_WC_REVOCATIONS:
   2946 			wapbl_replay_process_revocations(wr);
   2947 			break;
   2948 
   2949 		case WAPBL_WC_INODES:
   2950 			wapbl_replay_process_inodes(wr, saveoff, off);
   2951 			break;
   2952 
   2953 		default:
   2954 			printf("Unrecognized wapbl type: 0x%08x\n",
   2955 			       wcn->wc_type);
   2956  			error = EFTYPE;
   2957 			goto errout;
   2958 		}
   2959 		wapbl_circ_advance(wr, wcn->wc_len, &saveoff);
   2960 		if (off != saveoff) {
   2961 			printf("wapbl_replay: corrupted records\n");
   2962 			error = EFTYPE;
   2963 			goto errout;
   2964 		}
   2965 	}
   2966 	return 0;
   2967 
   2968  errout:
   2969 	wapbl_blkhash_clear(wr);
   2970 	return error;
   2971 }
   2972 
   2973 #if 0
   2974 int
   2975 wapbl_replay_verify(struct wapbl_replay *wr, struct vnode *fsdevvp)
   2976 {
   2977 	off_t off;
   2978 	int mismatchcnt = 0;
   2979 	int logblklen = 1 << wr->wr_log_dev_bshift;
   2980 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   2981 	void *scratch1 = wapbl_alloc(MAXBSIZE);
   2982 	void *scratch2 = wapbl_alloc(MAXBSIZE);
   2983 	int error = 0;
   2984 
   2985 	KDASSERT(wapbl_replay_isopen(wr));
   2986 
   2987 	off = wch->wc_tail;
   2988 	while (off != wch->wc_head) {
   2989 		struct wapbl_wc_null *wcn;
   2990 #ifdef DEBUG
   2991 		off_t saveoff = off;
   2992 #endif
   2993 		error = wapbl_circ_read(wr, wr->wr_scratch, logblklen, &off);
   2994 		if (error)
   2995 			goto out;
   2996 		wcn = (struct wapbl_wc_null *)wr->wr_scratch;
   2997 		switch (wcn->wc_type) {
   2998 		case WAPBL_WC_BLOCKS:
   2999 			{
   3000 				struct wapbl_wc_blocklist *wc =
   3001 				    (struct wapbl_wc_blocklist *)wr->wr_scratch;
   3002 				int i;
   3003 				for (i = 0; i < wc->wc_blkcount; i++) {
   3004 					int foundcnt = 0;
   3005 					int dirtycnt = 0;
   3006 					int j, n;
   3007 					/*
   3008 					 * Check each physical block into the
   3009 					 * hashtable independently
   3010 					 */
   3011 					n = wc->wc_blocks[i].wc_dlen >>
   3012 					    wch->wc_fs_dev_bshift;
   3013 					for (j = 0; j < n; j++) {
   3014 						struct wapbl_blk *wb =
   3015 						   wapbl_blkhash_get(wr,
   3016 						   wapbl_block_daddr(wc, i, j, fsblklen));
   3017 						if (wb && (wb->wb_off == off)) {
   3018 							foundcnt++;
   3019 							error =
   3020 							    wapbl_circ_read(wr,
   3021 							    scratch1, fsblklen,
   3022 							    &off);
   3023 							if (error)
   3024 								goto out;
   3025 							error =
   3026 							    wapbl_read(scratch2,
   3027 							    fsblklen, fsdevvp,
   3028 							    wb->wb_blk);
   3029 							if (error)
   3030 								goto out;
   3031 							if (memcmp(scratch1,
   3032 								   scratch2,
   3033 								   fsblklen)) {
   3034 								printf(
   3035 		"wapbl_verify: mismatch block %"PRId64" at off %"PRIdMAX"\n",
   3036 		wb->wb_blk, (intmax_t)off);
   3037 								dirtycnt++;
   3038 								mismatchcnt++;
   3039 							}
   3040 						} else {
   3041 							wapbl_circ_advance(wr,
   3042 							    fsblklen, &off);
   3043 						}
   3044 					}
   3045 #if 0
   3046 					/*
   3047 					 * If all of the blocks in an entry
   3048 					 * are clean, then remove all of its
   3049 					 * blocks from the hashtable since they
   3050 					 * never will need replay.
   3051 					 */
   3052 					if ((foundcnt != 0) &&
   3053 					    (dirtycnt == 0)) {
   3054 						off = saveoff;
   3055 						wapbl_circ_advance(wr,
   3056 						    logblklen, &off);
   3057 						for (j = 0; j < n; j++) {
   3058 							struct wapbl_blk *wb =
   3059 							   wapbl_blkhash_get(wr,
   3060 							   wapbl_block_daddr(wc, i, j, fsblklen));
   3061 							if (wb &&
   3062 							  (wb->wb_off == off)) {
   3063 								wapbl_blkhash_rem(wr, wb->wb_blk);
   3064 							}
   3065 							wapbl_circ_advance(wr,
   3066 							    fsblklen, &off);
   3067 						}
   3068 					}
   3069 #endif
   3070 				}
   3071 			}
   3072 			break;
   3073 		case WAPBL_WC_REVOCATIONS:
   3074 		case WAPBL_WC_INODES:
   3075 			break;
   3076 		default:
   3077 			KASSERT(0);
   3078 		}
   3079 #ifdef DEBUG
   3080 		wapbl_circ_advance(wr, wcn->wc_len, &saveoff);
   3081 		KASSERT(off == saveoff);
   3082 #endif
   3083 	}
   3084  out:
   3085 	wapbl_free(scratch1, MAXBSIZE);
   3086 	wapbl_free(scratch2, MAXBSIZE);
   3087 	if (!error && mismatchcnt)
   3088 		error = EFTYPE;
   3089 	return error;
   3090 }
   3091 #endif
   3092 
   3093 int
   3094 wapbl_replay_write(struct wapbl_replay *wr, struct vnode *fsdevvp)
   3095 {
   3096 	struct wapbl_blk *wb;
   3097 	size_t i;
   3098 	off_t off;
   3099 	void *scratch;
   3100 	int error = 0;
   3101 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   3102 
   3103 	KDASSERT(wapbl_replay_isopen(wr));
   3104 
   3105 	scratch = wapbl_alloc(MAXBSIZE);
   3106 
   3107 	for (i = 0; i <= wr->wr_blkhashmask; ++i) {
   3108 		LIST_FOREACH(wb, &wr->wr_blkhash[i], wb_hash) {
   3109 			off = wb->wb_off;
   3110 			error = wapbl_circ_read(wr, scratch, fsblklen, &off);
   3111 			if (error)
   3112 				break;
   3113 			error = wapbl_write(scratch, fsblklen, fsdevvp,
   3114 			    wb->wb_blk);
   3115 			if (error)
   3116 				break;
   3117 		}
   3118 	}
   3119 
   3120 	wapbl_free(scratch, MAXBSIZE);
   3121 	return error;
   3122 }
   3123 
   3124 int
   3125 wapbl_replay_can_read(struct wapbl_replay *wr, daddr_t blk, long len)
   3126 {
   3127 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   3128 
   3129 	KDASSERT(wapbl_replay_isopen(wr));
   3130 	KASSERT((len % fsblklen) == 0);
   3131 
   3132 	while (len != 0) {
   3133 		struct wapbl_blk *wb = wapbl_blkhash_get(wr, blk);
   3134 		if (wb)
   3135 			return 1;
   3136 		len -= fsblklen;
   3137 	}
   3138 	return 0;
   3139 }
   3140 
   3141 int
   3142 wapbl_replay_read(struct wapbl_replay *wr, void *data, daddr_t blk, long len)
   3143 {
   3144 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   3145 
   3146 	KDASSERT(wapbl_replay_isopen(wr));
   3147 
   3148 	KASSERT((len % fsblklen) == 0);
   3149 
   3150 	while (len != 0) {
   3151 		struct wapbl_blk *wb = wapbl_blkhash_get(wr, blk);
   3152 		if (wb) {
   3153 			off_t off = wb->wb_off;
   3154 			int error;
   3155 			error = wapbl_circ_read(wr, data, fsblklen, &off);
   3156 			if (error)
   3157 				return error;
   3158 		}
   3159 		data = (uint8_t *)data + fsblklen;
   3160 		len -= fsblklen;
   3161 		blk++;
   3162 	}
   3163 	return 0;
   3164 }
   3165 
   3166 #ifdef _KERNEL
   3167 
   3168 MODULE(MODULE_CLASS_VFS, wapbl, NULL);
   3169 
   3170 static int
   3171 wapbl_modcmd(modcmd_t cmd, void *arg)
   3172 {
   3173 
   3174 	switch (cmd) {
   3175 	case MODULE_CMD_INIT:
   3176 		wapbl_init();
   3177 		return 0;
   3178 	case MODULE_CMD_FINI:
   3179 		return wapbl_fini();
   3180 	default:
   3181 		return ENOTTY;
   3182 	}
   3183 }
   3184 #endif /* _KERNEL */
   3185