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vfs_wapbl.c revision 1.90
      1 /*	$NetBSD: vfs_wapbl.c,v 1.90 2017/03/17 03:16:29 riastradh 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 1.90 2017/03/17 03:16:29 riastradh 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/evcnt.h>
     52 #include <sys/file.h>
     53 #include <sys/kauth.h>
     54 #include <sys/kernel.h>
     55 #include <sys/module.h>
     56 #include <sys/mount.h>
     57 #include <sys/mutex.h>
     58 #include <sys/namei.h>
     59 #include <sys/proc.h>
     60 #include <sys/resourcevar.h>
     61 #include <sys/sysctl.h>
     62 #include <sys/uio.h>
     63 #include <sys/vnode.h>
     64 
     65 #include <miscfs/specfs/specdev.h>
     66 
     67 #define	wapbl_alloc(s) kmem_alloc((s), KM_SLEEP)
     68 #define	wapbl_free(a, s) kmem_free((a), (s))
     69 #define	wapbl_calloc(n, s) kmem_zalloc((n)*(s), KM_SLEEP)
     70 
     71 static struct sysctllog *wapbl_sysctl;
     72 static int wapbl_flush_disk_cache = 1;
     73 static int wapbl_verbose_commit = 0;
     74 
     75 static inline size_t wapbl_space_free(size_t, off_t, off_t);
     76 
     77 #else /* !_KERNEL */
     78 
     79 #include <assert.h>
     80 #include <errno.h>
     81 #include <stdbool.h>
     82 #include <stdio.h>
     83 #include <stdlib.h>
     84 #include <string.h>
     85 
     86 #define	KDASSERT(x) assert(x)
     87 #define	KASSERT(x) assert(x)
     88 #define	wapbl_alloc(s) malloc(s)
     89 #define	wapbl_free(a, s) free(a)
     90 #define	wapbl_calloc(n, s) calloc((n), (s))
     91 
     92 #endif /* !_KERNEL */
     93 
     94 /*
     95  * INTERNAL DATA STRUCTURES
     96  */
     97 
     98 /*
     99  * This structure holds per-mount log information.
    100  *
    101  * Legend:	a = atomic access only
    102  *		r = read-only after init
    103  *		l = rwlock held
    104  *		m = mutex held
    105  *		lm = rwlock held writing or mutex held
    106  *		u = unlocked access ok
    107  *		b = bufcache_lock held
    108  */
    109 LIST_HEAD(wapbl_ino_head, wapbl_ino);
    110 struct wapbl {
    111 	struct vnode *wl_logvp;	/* r:	log here */
    112 	struct vnode *wl_devvp;	/* r:	log on this device */
    113 	struct mount *wl_mount;	/* r:	mountpoint wl is associated with */
    114 	daddr_t wl_logpbn;	/* r:	Physical block number of start of log */
    115 	int wl_log_dev_bshift;	/* r:	logarithm of device block size of log
    116 					device */
    117 	int wl_fs_dev_bshift;	/* r:	logarithm of device block size of
    118 					filesystem device */
    119 
    120 	unsigned wl_lock_count;	/* m:	Count of transactions in progress */
    121 
    122 	size_t wl_circ_size; 	/* r:	Number of bytes in buffer of log */
    123 	size_t wl_circ_off;	/* r:	Number of bytes reserved at start */
    124 
    125 	size_t wl_bufcount_max;	/* r:	Number of buffers reserved for log */
    126 	size_t wl_bufbytes_max;	/* r:	Number of buf bytes reserved for log */
    127 
    128 	off_t wl_head;		/* l:	Byte offset of log head */
    129 	off_t wl_tail;		/* l:	Byte offset of log tail */
    130 	/*
    131 	 * WAPBL log layout, stored on wl_devvp at wl_logpbn:
    132 	 *
    133 	 *  ___________________ wl_circ_size __________________
    134 	 * /                                                   \
    135 	 * +---------+---------+-------+--------------+--------+
    136 	 * [ commit0 | commit1 | CCWCW | EEEEEEEEEEEE | CCCWCW ]
    137 	 * +---------+---------+-------+--------------+--------+
    138 	 *       wl_circ_off --^       ^-- wl_head    ^-- wl_tail
    139 	 *
    140 	 * commit0 and commit1 are commit headers.  A commit header has
    141 	 * a generation number, indicating which of the two headers is
    142 	 * more recent, and an assignment of head and tail pointers.
    143 	 * The rest is a circular queue of log records, starting at
    144 	 * the byte offset wl_circ_off.
    145 	 *
    146 	 * E marks empty space for records.
    147 	 * W marks records for block writes issued but waiting.
    148 	 * C marks completed records.
    149 	 *
    150 	 * wapbl_flush writes new records to empty `E' spaces after
    151 	 * wl_head from the current transaction in memory.
    152 	 *
    153 	 * wapbl_truncate advances wl_tail past any completed `C'
    154 	 * records, freeing them up for use.
    155 	 *
    156 	 * head == tail == 0 means log is empty.
    157 	 * head == tail != 0 means log is full.
    158 	 *
    159 	 * See assertions in wapbl_advance() for other boundary
    160 	 * conditions.
    161 	 *
    162 	 * Only wapbl_flush moves the head, except when wapbl_truncate
    163 	 * sets it to 0 to indicate that the log is empty.
    164 	 *
    165 	 * Only wapbl_truncate moves the tail, except when wapbl_flush
    166 	 * sets it to wl_circ_off to indicate that the log is full.
    167 	 */
    168 
    169 	struct wapbl_wc_header *wl_wc_header;	/* l	*/
    170 	void *wl_wc_scratch;	/* l:	scratch space (XXX: por que?!?) */
    171 
    172 	kmutex_t wl_mtx;	/* u:	short-term lock */
    173 	krwlock_t wl_rwlock;	/* u:	File system transaction lock */
    174 
    175 	/*
    176 	 * Must be held while accessing
    177 	 * wl_count or wl_bufs or head or tail
    178 	 */
    179 
    180 #if _KERNEL
    181 	/*
    182 	 * Callback called from within the flush routine to flush any extra
    183 	 * bits.  Note that flush may be skipped without calling this if
    184 	 * there are no outstanding buffers in the transaction.
    185 	 */
    186 	wapbl_flush_fn_t wl_flush;	/* r	*/
    187 	wapbl_flush_fn_t wl_flush_abort;/* r	*/
    188 
    189 	/* Event counters */
    190 	char wl_ev_group[EVCNT_STRING_MAX];	/* r	*/
    191 	struct evcnt wl_ev_commit;		/* l	*/
    192 	struct evcnt wl_ev_journalwrite;	/* l	*/
    193 	struct evcnt wl_ev_metawrite;		/* lm	*/
    194 	struct evcnt wl_ev_cacheflush;		/* l	*/
    195 #endif
    196 
    197 	size_t wl_bufbytes;	/* m:	Byte count of pages in wl_bufs */
    198 	size_t wl_bufcount;	/* m:	Count of buffers in wl_bufs */
    199 	size_t wl_bcount;	/* m:	Total bcount of wl_bufs */
    200 
    201 	LIST_HEAD(, buf) wl_bufs; /* m:	Buffers in current transaction */
    202 
    203 	kcondvar_t wl_reclaimable_cv;	/* m (obviously) */
    204 	size_t wl_reclaimable_bytes; /* m:	Amount of space available for
    205 						reclamation by truncate */
    206 	int wl_error_count;	/* m:	# of wl_entries with errors */
    207 	size_t wl_reserved_bytes; /* never truncate log smaller than this */
    208 
    209 #ifdef WAPBL_DEBUG_BUFBYTES
    210 	size_t wl_unsynced_bufbytes; /* Byte count of unsynced buffers */
    211 #endif
    212 
    213 #if _KERNEL
    214 	int wl_brperjblock;	/* r Block records per journal block */
    215 #endif
    216 
    217 	TAILQ_HEAD(, wapbl_dealloc) wl_dealloclist;	/* lm:	list head */
    218 	int wl_dealloccnt;				/* lm:	total count */
    219 	int wl_dealloclim;				/* r:	max count */
    220 
    221 	/* hashtable of inode numbers for allocated but unlinked inodes */
    222 	/* synch ??? */
    223 	struct wapbl_ino_head *wl_inohash;
    224 	u_long wl_inohashmask;
    225 	int wl_inohashcnt;
    226 
    227 	SIMPLEQ_HEAD(, wapbl_entry) wl_entries; /* On disk transaction
    228 						   accounting */
    229 
    230 	u_char *wl_buffer;	/* l:   buffer for wapbl_buffered_write() */
    231 	daddr_t wl_buffer_dblk;	/* l:   buffer disk block address */
    232 	size_t wl_buffer_used;	/* l:   buffer current use */
    233 };
    234 
    235 #ifdef WAPBL_DEBUG_PRINT
    236 int wapbl_debug_print = WAPBL_DEBUG_PRINT;
    237 #endif
    238 
    239 /****************************************************************/
    240 #ifdef _KERNEL
    241 
    242 #ifdef WAPBL_DEBUG
    243 struct wapbl *wapbl_debug_wl;
    244 #endif
    245 
    246 static int wapbl_write_commit(struct wapbl *wl, off_t head, off_t tail);
    247 static int wapbl_write_blocks(struct wapbl *wl, off_t *offp);
    248 static int wapbl_write_revocations(struct wapbl *wl, off_t *offp);
    249 static int wapbl_write_inodes(struct wapbl *wl, off_t *offp);
    250 #endif /* _KERNEL */
    251 
    252 static int wapbl_replay_process(struct wapbl_replay *wr, off_t, off_t);
    253 
    254 static inline size_t wapbl_space_used(size_t avail, off_t head,
    255 	off_t tail);
    256 
    257 #ifdef _KERNEL
    258 
    259 static struct pool wapbl_entry_pool;
    260 static struct pool wapbl_dealloc_pool;
    261 
    262 #define	WAPBL_INODETRK_SIZE 83
    263 static int wapbl_ino_pool_refcount;
    264 static struct pool wapbl_ino_pool;
    265 struct wapbl_ino {
    266 	LIST_ENTRY(wapbl_ino) wi_hash;
    267 	ino_t wi_ino;
    268 	mode_t wi_mode;
    269 };
    270 
    271 static void wapbl_inodetrk_init(struct wapbl *wl, u_int size);
    272 static void wapbl_inodetrk_free(struct wapbl *wl);
    273 static struct wapbl_ino *wapbl_inodetrk_get(struct wapbl *wl, ino_t ino);
    274 
    275 static size_t wapbl_transaction_len(struct wapbl *wl);
    276 static inline size_t wapbl_transaction_inodes_len(struct wapbl *wl);
    277 
    278 static void wapbl_deallocation_free(struct wapbl *, struct wapbl_dealloc *,
    279 	bool);
    280 
    281 static void wapbl_evcnt_init(struct wapbl *);
    282 static void wapbl_evcnt_free(struct wapbl *);
    283 
    284 #if 0
    285 int wapbl_replay_verify(struct wapbl_replay *, struct vnode *);
    286 #endif
    287 
    288 static int wapbl_replay_isopen1(struct wapbl_replay *);
    289 
    290 struct wapbl_ops wapbl_ops = {
    291 	.wo_wapbl_discard	= wapbl_discard,
    292 	.wo_wapbl_replay_isopen	= wapbl_replay_isopen1,
    293 	.wo_wapbl_replay_can_read = wapbl_replay_can_read,
    294 	.wo_wapbl_replay_read	= wapbl_replay_read,
    295 	.wo_wapbl_add_buf	= wapbl_add_buf,
    296 	.wo_wapbl_remove_buf	= wapbl_remove_buf,
    297 	.wo_wapbl_resize_buf	= wapbl_resize_buf,
    298 	.wo_wapbl_begin		= wapbl_begin,
    299 	.wo_wapbl_end		= wapbl_end,
    300 	.wo_wapbl_junlock_assert= wapbl_junlock_assert,
    301 
    302 	/* XXX: the following is only used to say "this is a wapbl buf" */
    303 	.wo_wapbl_biodone	= wapbl_biodone,
    304 };
    305 
    306 static int
    307 wapbl_sysctl_init(void)
    308 {
    309 	int rv;
    310 	const struct sysctlnode *rnode, *cnode;
    311 
    312 	wapbl_sysctl = NULL;
    313 
    314 	rv = sysctl_createv(&wapbl_sysctl, 0, NULL, &rnode,
    315 		       CTLFLAG_PERMANENT,
    316 		       CTLTYPE_NODE, "wapbl",
    317 		       SYSCTL_DESCR("WAPBL journaling options"),
    318 		       NULL, 0, NULL, 0,
    319 		       CTL_VFS, CTL_CREATE, CTL_EOL);
    320 	if (rv)
    321 		return rv;
    322 
    323 	rv = sysctl_createv(&wapbl_sysctl, 0, &rnode, &cnode,
    324 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
    325 		       CTLTYPE_INT, "flush_disk_cache",
    326 		       SYSCTL_DESCR("flush disk cache"),
    327 		       NULL, 0, &wapbl_flush_disk_cache, 0,
    328 		       CTL_CREATE, CTL_EOL);
    329 	if (rv)
    330 		return rv;
    331 
    332 	rv = sysctl_createv(&wapbl_sysctl, 0, &rnode, &cnode,
    333 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
    334 		       CTLTYPE_INT, "verbose_commit",
    335 		       SYSCTL_DESCR("show time and size of wapbl log commits"),
    336 		       NULL, 0, &wapbl_verbose_commit, 0,
    337 		       CTL_CREATE, CTL_EOL);
    338 	return rv;
    339 }
    340 
    341 static void
    342 wapbl_init(void)
    343 {
    344 
    345 	pool_init(&wapbl_entry_pool, sizeof(struct wapbl_entry), 0, 0, 0,
    346 	    "wapblentrypl", &pool_allocator_kmem, IPL_VM);
    347 	pool_init(&wapbl_dealloc_pool, sizeof(struct wapbl_dealloc), 0, 0, 0,
    348 	    "wapbldealloc", &pool_allocator_nointr, IPL_NONE);
    349 
    350 	wapbl_sysctl_init();
    351 }
    352 
    353 static int
    354 wapbl_fini(void)
    355 {
    356 
    357 	if (wapbl_sysctl != NULL)
    358 		 sysctl_teardown(&wapbl_sysctl);
    359 
    360 	pool_destroy(&wapbl_dealloc_pool);
    361 	pool_destroy(&wapbl_entry_pool);
    362 
    363 	return 0;
    364 }
    365 
    366 static void
    367 wapbl_evcnt_init(struct wapbl *wl)
    368 {
    369 	snprintf(wl->wl_ev_group, sizeof(wl->wl_ev_group),
    370 	    "wapbl fsid 0x%x/0x%x",
    371 	    wl->wl_mount->mnt_stat.f_fsidx.__fsid_val[0],
    372 	    wl->wl_mount->mnt_stat.f_fsidx.__fsid_val[1]
    373 	);
    374 
    375 	evcnt_attach_dynamic(&wl->wl_ev_commit, EVCNT_TYPE_MISC,
    376 	    NULL, wl->wl_ev_group, "commit");
    377 	evcnt_attach_dynamic(&wl->wl_ev_journalwrite, EVCNT_TYPE_MISC,
    378 	    NULL, wl->wl_ev_group, "journal sync block write");
    379 	evcnt_attach_dynamic(&wl->wl_ev_metawrite, EVCNT_TYPE_MISC,
    380 	    NULL, wl->wl_ev_group, "metadata finished block write");
    381 	evcnt_attach_dynamic(&wl->wl_ev_cacheflush, EVCNT_TYPE_MISC,
    382 	    NULL, wl->wl_ev_group, "cache flush");
    383 }
    384 
    385 static void
    386 wapbl_evcnt_free(struct wapbl *wl)
    387 {
    388 	evcnt_detach(&wl->wl_ev_commit);
    389 	evcnt_detach(&wl->wl_ev_journalwrite);
    390 	evcnt_detach(&wl->wl_ev_metawrite);
    391 	evcnt_detach(&wl->wl_ev_cacheflush);
    392 }
    393 
    394 static int
    395 wapbl_start_flush_inodes(struct wapbl *wl, struct wapbl_replay *wr)
    396 {
    397 	int error, i;
    398 
    399 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY,
    400 	    ("wapbl_start: reusing log with %d inodes\n", wr->wr_inodescnt));
    401 
    402 	/*
    403 	 * Its only valid to reuse the replay log if its
    404 	 * the same as the new log we just opened.
    405 	 */
    406 	KDASSERT(!wapbl_replay_isopen(wr));
    407 	KASSERT(wl->wl_devvp->v_type == VBLK);
    408 	KASSERT(wr->wr_devvp->v_type == VBLK);
    409 	KASSERT(wl->wl_devvp->v_rdev == wr->wr_devvp->v_rdev);
    410 	KASSERT(wl->wl_logpbn == wr->wr_logpbn);
    411 	KASSERT(wl->wl_circ_size == wr->wr_circ_size);
    412 	KASSERT(wl->wl_circ_off == wr->wr_circ_off);
    413 	KASSERT(wl->wl_log_dev_bshift == wr->wr_log_dev_bshift);
    414 	KASSERT(wl->wl_fs_dev_bshift == wr->wr_fs_dev_bshift);
    415 
    416 	wl->wl_wc_header->wc_generation = wr->wr_generation + 1;
    417 
    418 	for (i = 0; i < wr->wr_inodescnt; i++)
    419 		wapbl_register_inode(wl, wr->wr_inodes[i].wr_inumber,
    420 		    wr->wr_inodes[i].wr_imode);
    421 
    422 	/* Make sure new transaction won't overwrite old inodes list */
    423 	KDASSERT(wapbl_transaction_len(wl) <=
    424 	    wapbl_space_free(wl->wl_circ_size, wr->wr_inodeshead,
    425 	    wr->wr_inodestail));
    426 
    427 	wl->wl_head = wl->wl_tail = wr->wr_inodeshead;
    428 	wl->wl_reclaimable_bytes = wl->wl_reserved_bytes =
    429 	    wapbl_transaction_len(wl);
    430 
    431 	error = wapbl_write_inodes(wl, &wl->wl_head);
    432 	if (error)
    433 		return error;
    434 
    435 	KASSERT(wl->wl_head != wl->wl_tail);
    436 	KASSERT(wl->wl_head != 0);
    437 
    438 	return 0;
    439 }
    440 
    441 int
    442 wapbl_start(struct wapbl ** wlp, struct mount *mp, struct vnode *vp,
    443 	daddr_t off, size_t count, size_t blksize, struct wapbl_replay *wr,
    444 	wapbl_flush_fn_t flushfn, wapbl_flush_fn_t flushabortfn)
    445 {
    446 	struct wapbl *wl;
    447 	struct vnode *devvp;
    448 	daddr_t logpbn;
    449 	int error;
    450 	int log_dev_bshift = ilog2(blksize);
    451 	int fs_dev_bshift = log_dev_bshift;
    452 	int run;
    453 
    454 	WAPBL_PRINTF(WAPBL_PRINT_OPEN, ("wapbl_start: vp=%p off=%" PRId64
    455 	    " count=%zu blksize=%zu\n", vp, off, count, blksize));
    456 
    457 	if (log_dev_bshift > fs_dev_bshift) {
    458 		WAPBL_PRINTF(WAPBL_PRINT_OPEN,
    459 			("wapbl: log device's block size cannot be larger "
    460 			 "than filesystem's\n"));
    461 		/*
    462 		 * Not currently implemented, although it could be if
    463 		 * needed someday.
    464 		 */
    465 		return ENOSYS;
    466 	}
    467 
    468 	if (off < 0)
    469 		return EINVAL;
    470 
    471 	if (blksize < DEV_BSIZE)
    472 		return EINVAL;
    473 	if (blksize % DEV_BSIZE)
    474 		return EINVAL;
    475 
    476 	/* XXXTODO: verify that the full load is writable */
    477 
    478 	/*
    479 	 * XXX check for minimum log size
    480 	 * minimum is governed by minimum amount of space
    481 	 * to complete a transaction. (probably truncate)
    482 	 */
    483 	/* XXX for now pick something minimal */
    484 	if ((count * blksize) < MAXPHYS) {
    485 		return ENOSPC;
    486 	}
    487 
    488 	if ((error = VOP_BMAP(vp, off, &devvp, &logpbn, &run)) != 0) {
    489 		return error;
    490 	}
    491 
    492 	wl = wapbl_calloc(1, sizeof(*wl));
    493 	rw_init(&wl->wl_rwlock);
    494 	mutex_init(&wl->wl_mtx, MUTEX_DEFAULT, IPL_NONE);
    495 	cv_init(&wl->wl_reclaimable_cv, "wapblrec");
    496 	LIST_INIT(&wl->wl_bufs);
    497 	SIMPLEQ_INIT(&wl->wl_entries);
    498 
    499 	wl->wl_logvp = vp;
    500 	wl->wl_devvp = devvp;
    501 	wl->wl_mount = mp;
    502 	wl->wl_logpbn = logpbn;
    503 	wl->wl_log_dev_bshift = log_dev_bshift;
    504 	wl->wl_fs_dev_bshift = fs_dev_bshift;
    505 
    506 	wl->wl_flush = flushfn;
    507 	wl->wl_flush_abort = flushabortfn;
    508 
    509 	/* Reserve two log device blocks for the commit headers */
    510 	wl->wl_circ_off = 2<<wl->wl_log_dev_bshift;
    511 	wl->wl_circ_size = ((count * blksize) - wl->wl_circ_off);
    512 	/* truncate the log usage to a multiple of log_dev_bshift */
    513 	wl->wl_circ_size >>= wl->wl_log_dev_bshift;
    514 	wl->wl_circ_size <<= wl->wl_log_dev_bshift;
    515 
    516 	/*
    517 	 * wl_bufbytes_max limits the size of the in memory transaction space.
    518 	 * - Since buffers are allocated and accounted for in units of
    519 	 *   PAGE_SIZE it is required to be a multiple of PAGE_SIZE
    520 	 *   (i.e. 1<<PAGE_SHIFT)
    521 	 * - Since the log device has to be written in units of
    522 	 *   1<<wl_log_dev_bshift it is required to be a mulitple of
    523 	 *   1<<wl_log_dev_bshift.
    524 	 * - Since filesystem will provide data in units of 1<<wl_fs_dev_bshift,
    525 	 *   it is convenient to be a multiple of 1<<wl_fs_dev_bshift.
    526 	 * Therefore it must be multiple of the least common multiple of those
    527 	 * three quantities.  Fortunately, all of those quantities are
    528 	 * guaranteed to be a power of two, and the least common multiple of
    529 	 * a set of numbers which are all powers of two is simply the maximum
    530 	 * of those numbers.  Finally, the maximum logarithm of a power of two
    531 	 * is the same as the log of the maximum power of two.  So we can do
    532 	 * the following operations to size wl_bufbytes_max:
    533 	 */
    534 
    535 	/* XXX fix actual number of pages reserved per filesystem. */
    536 	wl->wl_bufbytes_max = MIN(wl->wl_circ_size, buf_memcalc() / 2);
    537 
    538 	/* Round wl_bufbytes_max to the largest power of two constraint */
    539 	wl->wl_bufbytes_max >>= PAGE_SHIFT;
    540 	wl->wl_bufbytes_max <<= PAGE_SHIFT;
    541 	wl->wl_bufbytes_max >>= wl->wl_log_dev_bshift;
    542 	wl->wl_bufbytes_max <<= wl->wl_log_dev_bshift;
    543 	wl->wl_bufbytes_max >>= wl->wl_fs_dev_bshift;
    544 	wl->wl_bufbytes_max <<= wl->wl_fs_dev_bshift;
    545 
    546 	/* XXX maybe use filesystem fragment size instead of 1024 */
    547 	/* XXX fix actual number of buffers reserved per filesystem. */
    548 	wl->wl_bufcount_max = (nbuf / 2) * 1024;
    549 
    550 	wl->wl_brperjblock = ((1<<wl->wl_log_dev_bshift)
    551 	    - offsetof(struct wapbl_wc_blocklist, wc_blocks)) /
    552 	    sizeof(((struct wapbl_wc_blocklist *)0)->wc_blocks[0]);
    553 	KASSERT(wl->wl_brperjblock > 0);
    554 
    555 	/* XXX tie this into resource estimation */
    556 	wl->wl_dealloclim = wl->wl_bufbytes_max / mp->mnt_stat.f_bsize / 2;
    557 	TAILQ_INIT(&wl->wl_dealloclist);
    558 
    559 	wl->wl_buffer = wapbl_alloc(MAXPHYS);
    560 	wl->wl_buffer_used = 0;
    561 
    562 	wapbl_inodetrk_init(wl, WAPBL_INODETRK_SIZE);
    563 
    564 	wapbl_evcnt_init(wl);
    565 
    566 	/* Initialize the commit header */
    567 	{
    568 		struct wapbl_wc_header *wc;
    569 		size_t len = 1 << wl->wl_log_dev_bshift;
    570 		wc = wapbl_calloc(1, len);
    571 		wc->wc_type = WAPBL_WC_HEADER;
    572 		wc->wc_len = len;
    573 		wc->wc_circ_off = wl->wl_circ_off;
    574 		wc->wc_circ_size = wl->wl_circ_size;
    575 		/* XXX wc->wc_fsid */
    576 		wc->wc_log_dev_bshift = wl->wl_log_dev_bshift;
    577 		wc->wc_fs_dev_bshift = wl->wl_fs_dev_bshift;
    578 		wl->wl_wc_header = wc;
    579 		wl->wl_wc_scratch = wapbl_alloc(len);
    580 	}
    581 
    582 	/*
    583 	 * if there was an existing set of unlinked but
    584 	 * allocated inodes, preserve it in the new
    585 	 * log.
    586 	 */
    587 	if (wr && wr->wr_inodescnt) {
    588 		error = wapbl_start_flush_inodes(wl, wr);
    589 		if (error)
    590 			goto errout;
    591 	}
    592 
    593 	error = wapbl_write_commit(wl, wl->wl_head, wl->wl_tail);
    594 	if (error) {
    595 		goto errout;
    596 	}
    597 
    598 	*wlp = wl;
    599 #if defined(WAPBL_DEBUG)
    600 	wapbl_debug_wl = wl;
    601 #endif
    602 
    603 	return 0;
    604  errout:
    605 	wapbl_discard(wl);
    606 	wapbl_free(wl->wl_wc_scratch, wl->wl_wc_header->wc_len);
    607 	wapbl_free(wl->wl_wc_header, wl->wl_wc_header->wc_len);
    608 	wapbl_free(wl->wl_buffer, MAXPHYS);
    609 	wapbl_inodetrk_free(wl);
    610 	wapbl_free(wl, sizeof(*wl));
    611 
    612 	return error;
    613 }
    614 
    615 /*
    616  * Like wapbl_flush, only discards the transaction
    617  * completely
    618  */
    619 
    620 void
    621 wapbl_discard(struct wapbl *wl)
    622 {
    623 	struct wapbl_entry *we;
    624 	struct wapbl_dealloc *wd;
    625 	struct buf *bp;
    626 	int i;
    627 
    628 	/*
    629 	 * XXX we may consider using upgrade here
    630 	 * if we want to call flush from inside a transaction
    631 	 */
    632 	rw_enter(&wl->wl_rwlock, RW_WRITER);
    633 	wl->wl_flush(wl->wl_mount, TAILQ_FIRST(&wl->wl_dealloclist));
    634 
    635 #ifdef WAPBL_DEBUG_PRINT
    636 	{
    637 		pid_t pid = -1;
    638 		lwpid_t lid = -1;
    639 		if (curproc)
    640 			pid = curproc->p_pid;
    641 		if (curlwp)
    642 			lid = curlwp->l_lid;
    643 #ifdef WAPBL_DEBUG_BUFBYTES
    644 		WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
    645 		    ("wapbl_discard: thread %d.%d discarding "
    646 		    "transaction\n"
    647 		    "\tbufcount=%zu bufbytes=%zu bcount=%zu "
    648 		    "deallocs=%d inodes=%d\n"
    649 		    "\terrcnt = %u, reclaimable=%zu reserved=%zu "
    650 		    "unsynced=%zu\n",
    651 		    pid, lid, wl->wl_bufcount, wl->wl_bufbytes,
    652 		    wl->wl_bcount, wl->wl_dealloccnt,
    653 		    wl->wl_inohashcnt, wl->wl_error_count,
    654 		    wl->wl_reclaimable_bytes, wl->wl_reserved_bytes,
    655 		    wl->wl_unsynced_bufbytes));
    656 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
    657 			WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
    658 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
    659 			     "error = %d, unsynced = %zu\n",
    660 			     we->we_bufcount, we->we_reclaimable_bytes,
    661 			     we->we_error, we->we_unsynced_bufbytes));
    662 		}
    663 #else /* !WAPBL_DEBUG_BUFBYTES */
    664 		WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
    665 		    ("wapbl_discard: thread %d.%d discarding transaction\n"
    666 		    "\tbufcount=%zu bufbytes=%zu bcount=%zu "
    667 		    "deallocs=%d inodes=%d\n"
    668 		    "\terrcnt = %u, reclaimable=%zu reserved=%zu\n",
    669 		    pid, lid, wl->wl_bufcount, wl->wl_bufbytes,
    670 		    wl->wl_bcount, wl->wl_dealloccnt,
    671 		    wl->wl_inohashcnt, wl->wl_error_count,
    672 		    wl->wl_reclaimable_bytes, wl->wl_reserved_bytes));
    673 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
    674 			WAPBL_PRINTF(WAPBL_PRINT_DISCARD,
    675 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
    676 			     "error = %d\n",
    677 			     we->we_bufcount, we->we_reclaimable_bytes,
    678 			     we->we_error));
    679 		}
    680 #endif /* !WAPBL_DEBUG_BUFBYTES */
    681 	}
    682 #endif /* WAPBL_DEBUG_PRINT */
    683 
    684 	for (i = 0; i <= wl->wl_inohashmask; i++) {
    685 		struct wapbl_ino_head *wih;
    686 		struct wapbl_ino *wi;
    687 
    688 		wih = &wl->wl_inohash[i];
    689 		while ((wi = LIST_FIRST(wih)) != NULL) {
    690 			LIST_REMOVE(wi, wi_hash);
    691 			pool_put(&wapbl_ino_pool, wi);
    692 			KASSERT(wl->wl_inohashcnt > 0);
    693 			wl->wl_inohashcnt--;
    694 		}
    695 	}
    696 
    697 	/*
    698 	 * clean buffer list
    699 	 */
    700 	mutex_enter(&bufcache_lock);
    701 	mutex_enter(&wl->wl_mtx);
    702 	while ((bp = LIST_FIRST(&wl->wl_bufs)) != NULL) {
    703 		if (bbusy(bp, 0, 0, &wl->wl_mtx) == 0) {
    704 			/*
    705 			 * The buffer will be unlocked and
    706 			 * removed from the transaction in brelse
    707 			 */
    708 			mutex_exit(&wl->wl_mtx);
    709 			brelsel(bp, 0);
    710 			mutex_enter(&wl->wl_mtx);
    711 		}
    712 	}
    713 	mutex_exit(&wl->wl_mtx);
    714 	mutex_exit(&bufcache_lock);
    715 
    716 	/*
    717 	 * Remove references to this wl from wl_entries, free any which
    718 	 * no longer have buffers, others will be freed in wapbl_biodone
    719 	 * when they no longer have any buffers.
    720 	 */
    721 	while ((we = SIMPLEQ_FIRST(&wl->wl_entries)) != NULL) {
    722 		SIMPLEQ_REMOVE_HEAD(&wl->wl_entries, we_entries);
    723 		/* XXX should we be accumulating wl_error_count
    724 		 * and increasing reclaimable bytes ? */
    725 		we->we_wapbl = NULL;
    726 		if (we->we_bufcount == 0) {
    727 #ifdef WAPBL_DEBUG_BUFBYTES
    728 			KASSERT(we->we_unsynced_bufbytes == 0);
    729 #endif
    730 			pool_put(&wapbl_entry_pool, we);
    731 		}
    732 	}
    733 
    734 	/* Discard list of deallocs */
    735 	while ((wd = TAILQ_FIRST(&wl->wl_dealloclist)) != NULL)
    736 		wapbl_deallocation_free(wl, wd, true);
    737 
    738 	/* XXX should we clear wl_reserved_bytes? */
    739 
    740 	KASSERT(wl->wl_bufbytes == 0);
    741 	KASSERT(wl->wl_bcount == 0);
    742 	KASSERT(wl->wl_bufcount == 0);
    743 	KASSERT(LIST_EMPTY(&wl->wl_bufs));
    744 	KASSERT(SIMPLEQ_EMPTY(&wl->wl_entries));
    745 	KASSERT(wl->wl_inohashcnt == 0);
    746 	KASSERT(TAILQ_EMPTY(&wl->wl_dealloclist));
    747 	KASSERT(wl->wl_dealloccnt == 0);
    748 
    749 	rw_exit(&wl->wl_rwlock);
    750 }
    751 
    752 int
    753 wapbl_stop(struct wapbl *wl, int force)
    754 {
    755 	int error;
    756 
    757 	WAPBL_PRINTF(WAPBL_PRINT_OPEN, ("wapbl_stop called\n"));
    758 	error = wapbl_flush(wl, 1);
    759 	if (error) {
    760 		if (force)
    761 			wapbl_discard(wl);
    762 		else
    763 			return error;
    764 	}
    765 
    766 	/* Unlinked inodes persist after a flush */
    767 	if (wl->wl_inohashcnt) {
    768 		if (force) {
    769 			wapbl_discard(wl);
    770 		} else {
    771 			return EBUSY;
    772 		}
    773 	}
    774 
    775 	KASSERT(wl->wl_bufbytes == 0);
    776 	KASSERT(wl->wl_bcount == 0);
    777 	KASSERT(wl->wl_bufcount == 0);
    778 	KASSERT(LIST_EMPTY(&wl->wl_bufs));
    779 	KASSERT(wl->wl_dealloccnt == 0);
    780 	KASSERT(SIMPLEQ_EMPTY(&wl->wl_entries));
    781 	KASSERT(wl->wl_inohashcnt == 0);
    782 	KASSERT(TAILQ_EMPTY(&wl->wl_dealloclist));
    783 	KASSERT(wl->wl_dealloccnt == 0);
    784 
    785 	wapbl_free(wl->wl_wc_scratch, wl->wl_wc_header->wc_len);
    786 	wapbl_free(wl->wl_wc_header, wl->wl_wc_header->wc_len);
    787 	wapbl_free(wl->wl_buffer, MAXPHYS);
    788 	wapbl_inodetrk_free(wl);
    789 
    790 	wapbl_evcnt_free(wl);
    791 
    792 	cv_destroy(&wl->wl_reclaimable_cv);
    793 	mutex_destroy(&wl->wl_mtx);
    794 	rw_destroy(&wl->wl_rwlock);
    795 	wapbl_free(wl, sizeof(*wl));
    796 
    797 	return 0;
    798 }
    799 
    800 /****************************************************************/
    801 /*
    802  * Unbuffered disk I/O
    803  */
    804 
    805 static int
    806 wapbl_doio(void *data, size_t len, struct vnode *devvp, daddr_t pbn, int flags)
    807 {
    808 	struct pstats *pstats = curlwp->l_proc->p_stats;
    809 	struct buf *bp;
    810 	int error;
    811 
    812 	KASSERT((flags & ~(B_WRITE | B_READ)) == 0);
    813 	KASSERT(devvp->v_type == VBLK);
    814 
    815 	if ((flags & (B_WRITE | B_READ)) == B_WRITE) {
    816 		mutex_enter(devvp->v_interlock);
    817 		devvp->v_numoutput++;
    818 		mutex_exit(devvp->v_interlock);
    819 		pstats->p_ru.ru_oublock++;
    820 	} else {
    821 		pstats->p_ru.ru_inblock++;
    822 	}
    823 
    824 	bp = getiobuf(devvp, true);
    825 	bp->b_flags = flags;
    826 	bp->b_cflags = BC_BUSY; /* silly & dubious */
    827 	bp->b_dev = devvp->v_rdev;
    828 	bp->b_data = data;
    829 	bp->b_bufsize = bp->b_resid = bp->b_bcount = len;
    830 	bp->b_blkno = pbn;
    831 	BIO_SETPRIO(bp, BPRIO_TIMECRITICAL);
    832 
    833 	WAPBL_PRINTF(WAPBL_PRINT_IO,
    834 	    ("wapbl_doio: %s %d bytes at block %"PRId64" on dev 0x%"PRIx64"\n",
    835 	    BUF_ISWRITE(bp) ? "write" : "read", bp->b_bcount,
    836 	    bp->b_blkno, bp->b_dev));
    837 
    838 	VOP_STRATEGY(devvp, bp);
    839 
    840 	error = biowait(bp);
    841 	putiobuf(bp);
    842 
    843 	if (error) {
    844 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
    845 		    ("wapbl_doio: %s %zu bytes at block %" PRId64
    846 		    " on dev 0x%"PRIx64" failed with error %d\n",
    847 		    (((flags & (B_WRITE | B_READ)) == B_WRITE) ?
    848 		     "write" : "read"),
    849 		    len, pbn, devvp->v_rdev, error));
    850 	}
    851 
    852 	return error;
    853 }
    854 
    855 /*
    856  * wapbl_write(data, len, devvp, pbn)
    857  *
    858  *	Synchronously write len bytes from data to physical block pbn
    859  *	on devvp.
    860  */
    861 int
    862 wapbl_write(void *data, size_t len, struct vnode *devvp, daddr_t pbn)
    863 {
    864 
    865 	return wapbl_doio(data, len, devvp, pbn, B_WRITE);
    866 }
    867 
    868 /*
    869  * wapbl_read(data, len, devvp, pbn)
    870  *
    871  *	Synchronously read len bytes into data from physical block pbn
    872  *	on devvp.
    873  */
    874 int
    875 wapbl_read(void *data, size_t len, struct vnode *devvp, daddr_t pbn)
    876 {
    877 
    878 	return wapbl_doio(data, len, devvp, pbn, B_READ);
    879 }
    880 
    881 /****************************************************************/
    882 /*
    883  * Buffered disk writes -- try to coalesce writes and emit
    884  * MAXPHYS-aligned blocks.
    885  */
    886 
    887 /*
    888  * wapbl_buffered_flush(wl)
    889  *
    890  *	Flush any buffered writes from wapbl_buffered_write.
    891  */
    892 static int
    893 wapbl_buffered_flush(struct wapbl *wl)
    894 {
    895 	int error;
    896 
    897 	if (wl->wl_buffer_used == 0)
    898 		return 0;
    899 
    900 	error = wapbl_doio(wl->wl_buffer, wl->wl_buffer_used,
    901 	    wl->wl_devvp, wl->wl_buffer_dblk, B_WRITE);
    902 	wl->wl_buffer_used = 0;
    903 
    904 	wl->wl_ev_journalwrite.ev_count++;
    905 
    906 	return error;
    907 }
    908 
    909 /*
    910  * wapbl_buffered_write(data, len, wl, pbn)
    911  *
    912  *	Write len bytes from data to physical block pbn on
    913  *	wl->wl_devvp.  The write may not complete until
    914  *	wapbl_buffered_flush.
    915  */
    916 static int
    917 wapbl_buffered_write(void *data, size_t len, struct wapbl *wl, daddr_t pbn)
    918 {
    919 	int error;
    920 	size_t resid;
    921 
    922 	/*
    923 	 * If not adjacent to buffered data flush first.  Disk block
    924 	 * address is always valid for non-empty buffer.
    925 	 */
    926 	if (wl->wl_buffer_used > 0 &&
    927 	    pbn != wl->wl_buffer_dblk + btodb(wl->wl_buffer_used)) {
    928 		error = wapbl_buffered_flush(wl);
    929 		if (error)
    930 			return error;
    931 	}
    932 	/*
    933 	 * If this write goes to an empty buffer we have to
    934 	 * save the disk block address first.
    935 	 */
    936 	if (wl->wl_buffer_used == 0)
    937 		wl->wl_buffer_dblk = pbn;
    938 	/*
    939 	 * Remaining space so this buffer ends on a MAXPHYS boundary.
    940 	 *
    941 	 * Cannot become less or equal zero as the buffer would have been
    942 	 * flushed on the last call then.
    943 	 */
    944 	resid = MAXPHYS - dbtob(wl->wl_buffer_dblk % btodb(MAXPHYS)) -
    945 	    wl->wl_buffer_used;
    946 	KASSERT(resid > 0);
    947 	KASSERT(dbtob(btodb(resid)) == resid);
    948 	if (len >= resid) {
    949 		memcpy(wl->wl_buffer + wl->wl_buffer_used, data, resid);
    950 		wl->wl_buffer_used += resid;
    951 		error = wapbl_doio(wl->wl_buffer, wl->wl_buffer_used,
    952 		    wl->wl_devvp, wl->wl_buffer_dblk, B_WRITE);
    953 		data = (uint8_t *)data + resid;
    954 		len -= resid;
    955 		wl->wl_buffer_dblk = pbn + btodb(resid);
    956 		wl->wl_buffer_used = 0;
    957 		if (error)
    958 			return error;
    959 	}
    960 	KASSERT(len < MAXPHYS);
    961 	if (len > 0) {
    962 		memcpy(wl->wl_buffer + wl->wl_buffer_used, data, len);
    963 		wl->wl_buffer_used += len;
    964 	}
    965 
    966 	return 0;
    967 }
    968 
    969 /*
    970  * wapbl_circ_write(wl, data, len, offp)
    971  *
    972  *	Write len bytes from data to the circular queue of wl, starting
    973  *	at linear byte offset *offp, and returning the new linear byte
    974  *	offset in *offp.
    975  *
    976  *	If the starting linear byte offset precedes wl->wl_circ_off,
    977  *	the write instead begins at wl->wl_circ_off.  XXX WTF?  This
    978  *	should be a KASSERT, not a conditional.
    979  *
    980  *	The write is buffered in wl and must be flushed with
    981  *	wapbl_buffered_flush before it will be submitted to the disk.
    982  */
    983 static int
    984 wapbl_circ_write(struct wapbl *wl, void *data, size_t len, off_t *offp)
    985 {
    986 	size_t slen;
    987 	off_t off = *offp;
    988 	int error;
    989 	daddr_t pbn;
    990 
    991 	KDASSERT(((len >> wl->wl_log_dev_bshift) <<
    992 	    wl->wl_log_dev_bshift) == len);
    993 
    994 	if (off < wl->wl_circ_off)
    995 		off = wl->wl_circ_off;
    996 	slen = wl->wl_circ_off + wl->wl_circ_size - off;
    997 	if (slen < len) {
    998 		pbn = wl->wl_logpbn + (off >> wl->wl_log_dev_bshift);
    999 #ifdef _KERNEL
   1000 		pbn = btodb(pbn << wl->wl_log_dev_bshift);
   1001 #endif
   1002 		error = wapbl_buffered_write(data, slen, wl, pbn);
   1003 		if (error)
   1004 			return error;
   1005 		data = (uint8_t *)data + slen;
   1006 		len -= slen;
   1007 		off = wl->wl_circ_off;
   1008 	}
   1009 	pbn = wl->wl_logpbn + (off >> wl->wl_log_dev_bshift);
   1010 #ifdef _KERNEL
   1011 	pbn = btodb(pbn << wl->wl_log_dev_bshift);
   1012 #endif
   1013 	error = wapbl_buffered_write(data, len, wl, pbn);
   1014 	if (error)
   1015 		return error;
   1016 	off += len;
   1017 	if (off >= wl->wl_circ_off + wl->wl_circ_size)
   1018 		off = wl->wl_circ_off;
   1019 	*offp = off;
   1020 	return 0;
   1021 }
   1022 
   1023 /****************************************************************/
   1024 /*
   1025  * WAPBL transactions: entering, adding/removing bufs, and exiting
   1026  */
   1027 
   1028 int
   1029 wapbl_begin(struct wapbl *wl, const char *file, int line)
   1030 {
   1031 	int doflush;
   1032 	unsigned lockcount;
   1033 
   1034 	KDASSERT(wl);
   1035 
   1036 	/*
   1037 	 * XXX this needs to be made much more sophisticated.
   1038 	 * perhaps each wapbl_begin could reserve a specified
   1039 	 * number of buffers and bytes.
   1040 	 */
   1041 	mutex_enter(&wl->wl_mtx);
   1042 	lockcount = wl->wl_lock_count;
   1043 	doflush = ((wl->wl_bufbytes + (lockcount * MAXPHYS)) >
   1044 		   wl->wl_bufbytes_max / 2) ||
   1045 		  ((wl->wl_bufcount + (lockcount * 10)) >
   1046 		   wl->wl_bufcount_max / 2) ||
   1047 		  (wapbl_transaction_len(wl) > wl->wl_circ_size / 2) ||
   1048 		  (wl->wl_dealloccnt >= (wl->wl_dealloclim / 2));
   1049 	mutex_exit(&wl->wl_mtx);
   1050 
   1051 	if (doflush) {
   1052 		WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
   1053 		    ("force flush lockcnt=%d bufbytes=%zu "
   1054 		    "(max=%zu) bufcount=%zu (max=%zu) "
   1055 		    "dealloccnt %d (lim=%d)\n",
   1056 		    lockcount, wl->wl_bufbytes,
   1057 		    wl->wl_bufbytes_max, wl->wl_bufcount,
   1058 		    wl->wl_bufcount_max,
   1059 		    wl->wl_dealloccnt, wl->wl_dealloclim));
   1060 	}
   1061 
   1062 	if (doflush) {
   1063 		int error = wapbl_flush(wl, 0);
   1064 		if (error)
   1065 			return error;
   1066 	}
   1067 
   1068 	rw_enter(&wl->wl_rwlock, RW_READER);
   1069 	mutex_enter(&wl->wl_mtx);
   1070 	wl->wl_lock_count++;
   1071 	mutex_exit(&wl->wl_mtx);
   1072 
   1073 #if defined(WAPBL_DEBUG_PRINT)
   1074 	WAPBL_PRINTF(WAPBL_PRINT_TRANSACTION,
   1075 	    ("wapbl_begin thread %d.%d with bufcount=%zu "
   1076 	    "bufbytes=%zu bcount=%zu at %s:%d\n",
   1077 	    curproc->p_pid, curlwp->l_lid, wl->wl_bufcount,
   1078 	    wl->wl_bufbytes, wl->wl_bcount, file, line));
   1079 #endif
   1080 
   1081 	return 0;
   1082 }
   1083 
   1084 void
   1085 wapbl_end(struct wapbl *wl)
   1086 {
   1087 
   1088 #if defined(WAPBL_DEBUG_PRINT)
   1089 	WAPBL_PRINTF(WAPBL_PRINT_TRANSACTION,
   1090 	     ("wapbl_end thread %d.%d with bufcount=%zu "
   1091 	      "bufbytes=%zu bcount=%zu\n",
   1092 	      curproc->p_pid, curlwp->l_lid, wl->wl_bufcount,
   1093 	      wl->wl_bufbytes, wl->wl_bcount));
   1094 #endif
   1095 
   1096 	/*
   1097 	 * XXX this could be handled more gracefully, perhaps place
   1098 	 * only a partial transaction in the log and allow the
   1099 	 * remaining to flush without the protection of the journal.
   1100 	 */
   1101 	KASSERTMSG((wapbl_transaction_len(wl) <=
   1102 		(wl->wl_circ_size - wl->wl_reserved_bytes)),
   1103 	    "wapbl_end: current transaction too big to flush");
   1104 
   1105 	mutex_enter(&wl->wl_mtx);
   1106 	KASSERT(wl->wl_lock_count > 0);
   1107 	wl->wl_lock_count--;
   1108 	mutex_exit(&wl->wl_mtx);
   1109 
   1110 	rw_exit(&wl->wl_rwlock);
   1111 }
   1112 
   1113 void
   1114 wapbl_add_buf(struct wapbl *wl, struct buf * bp)
   1115 {
   1116 
   1117 	KASSERT(bp->b_cflags & BC_BUSY);
   1118 	KASSERT(bp->b_vp);
   1119 
   1120 	wapbl_jlock_assert(wl);
   1121 
   1122 #if 0
   1123 	/*
   1124 	 * XXX this might be an issue for swapfiles.
   1125 	 * see uvm_swap.c:1702
   1126 	 *
   1127 	 * XXX2 why require it then?  leap of semantics?
   1128 	 */
   1129 	KASSERT((bp->b_cflags & BC_NOCACHE) == 0);
   1130 #endif
   1131 
   1132 	mutex_enter(&wl->wl_mtx);
   1133 	if (bp->b_flags & B_LOCKED) {
   1134 		LIST_REMOVE(bp, b_wapbllist);
   1135 		WAPBL_PRINTF(WAPBL_PRINT_BUFFER2,
   1136 		   ("wapbl_add_buf thread %d.%d re-adding buf %p "
   1137 		    "with %d bytes %d bcount\n",
   1138 		    curproc->p_pid, curlwp->l_lid, bp, bp->b_bufsize,
   1139 		    bp->b_bcount));
   1140 	} else {
   1141 		/* unlocked by dirty buffers shouldn't exist */
   1142 		KASSERT(!(bp->b_oflags & BO_DELWRI));
   1143 		wl->wl_bufbytes += bp->b_bufsize;
   1144 		wl->wl_bcount += bp->b_bcount;
   1145 		wl->wl_bufcount++;
   1146 		WAPBL_PRINTF(WAPBL_PRINT_BUFFER,
   1147 		   ("wapbl_add_buf thread %d.%d adding buf %p "
   1148 		    "with %d bytes %d bcount\n",
   1149 		    curproc->p_pid, curlwp->l_lid, bp, bp->b_bufsize,
   1150 		    bp->b_bcount));
   1151 	}
   1152 	LIST_INSERT_HEAD(&wl->wl_bufs, bp, b_wapbllist);
   1153 	mutex_exit(&wl->wl_mtx);
   1154 
   1155 	bp->b_flags |= B_LOCKED;
   1156 }
   1157 
   1158 static void
   1159 wapbl_remove_buf_locked(struct wapbl * wl, struct buf *bp)
   1160 {
   1161 
   1162 	KASSERT(mutex_owned(&wl->wl_mtx));
   1163 	KASSERT(bp->b_cflags & BC_BUSY);
   1164 	wapbl_jlock_assert(wl);
   1165 
   1166 #if 0
   1167 	/*
   1168 	 * XXX this might be an issue for swapfiles.
   1169 	 * see uvm_swap.c:1725
   1170 	 *
   1171 	 * XXXdeux: see above
   1172 	 */
   1173 	KASSERT((bp->b_flags & BC_NOCACHE) == 0);
   1174 #endif
   1175 	KASSERT(bp->b_flags & B_LOCKED);
   1176 
   1177 	WAPBL_PRINTF(WAPBL_PRINT_BUFFER,
   1178 	   ("wapbl_remove_buf thread %d.%d removing buf %p with "
   1179 	    "%d bytes %d bcount\n",
   1180 	    curproc->p_pid, curlwp->l_lid, bp, bp->b_bufsize, bp->b_bcount));
   1181 
   1182 	KASSERT(wl->wl_bufbytes >= bp->b_bufsize);
   1183 	wl->wl_bufbytes -= bp->b_bufsize;
   1184 	KASSERT(wl->wl_bcount >= bp->b_bcount);
   1185 	wl->wl_bcount -= bp->b_bcount;
   1186 	KASSERT(wl->wl_bufcount > 0);
   1187 	wl->wl_bufcount--;
   1188 	KASSERT((wl->wl_bufcount == 0) == (wl->wl_bufbytes == 0));
   1189 	KASSERT((wl->wl_bufcount == 0) == (wl->wl_bcount == 0));
   1190 	LIST_REMOVE(bp, b_wapbllist);
   1191 
   1192 	bp->b_flags &= ~B_LOCKED;
   1193 }
   1194 
   1195 /* called from brelsel() in vfs_bio among other places */
   1196 void
   1197 wapbl_remove_buf(struct wapbl * wl, struct buf *bp)
   1198 {
   1199 
   1200 	mutex_enter(&wl->wl_mtx);
   1201 	wapbl_remove_buf_locked(wl, bp);
   1202 	mutex_exit(&wl->wl_mtx);
   1203 }
   1204 
   1205 void
   1206 wapbl_resize_buf(struct wapbl *wl, struct buf *bp, long oldsz, long oldcnt)
   1207 {
   1208 
   1209 	KASSERT(bp->b_cflags & BC_BUSY);
   1210 
   1211 	/*
   1212 	 * XXX: why does this depend on B_LOCKED?  otherwise the buf
   1213 	 * is not for a transaction?  if so, why is this called in the
   1214 	 * first place?
   1215 	 */
   1216 	if (bp->b_flags & B_LOCKED) {
   1217 		mutex_enter(&wl->wl_mtx);
   1218 		wl->wl_bufbytes += bp->b_bufsize - oldsz;
   1219 		wl->wl_bcount += bp->b_bcount - oldcnt;
   1220 		mutex_exit(&wl->wl_mtx);
   1221 	}
   1222 }
   1223 
   1224 #endif /* _KERNEL */
   1225 
   1226 /****************************************************************/
   1227 /* Some utility inlines */
   1228 
   1229 /*
   1230  * wapbl_space_used(avail, head, tail)
   1231  *
   1232  *	Number of bytes used in a circular queue of avail total bytes,
   1233  *	from tail to head.
   1234  */
   1235 static inline size_t
   1236 wapbl_space_used(size_t avail, off_t head, off_t tail)
   1237 {
   1238 
   1239 	if (tail == 0) {
   1240 		KASSERT(head == 0);
   1241 		return 0;
   1242 	}
   1243 	return ((head + (avail - 1) - tail) % avail) + 1;
   1244 }
   1245 
   1246 #ifdef _KERNEL
   1247 /*
   1248  * wapbl_advance(size, off, oldoff, delta)
   1249  *
   1250  *	Given a byte offset oldoff into a circular queue of size bytes
   1251  *	starting at off, return a new byte offset oldoff + delta into
   1252  *	the circular queue.
   1253  */
   1254 static inline off_t
   1255 wapbl_advance(size_t size, size_t off, off_t oldoff, size_t delta)
   1256 {
   1257 	off_t newoff;
   1258 
   1259 	/* Define acceptable ranges for inputs. */
   1260 	KASSERT(delta <= (size_t)size);
   1261 	KASSERT((oldoff == 0) || ((size_t)oldoff >= off));
   1262 	KASSERT(oldoff < (off_t)(size + off));
   1263 
   1264 	if ((oldoff == 0) && (delta != 0))
   1265 		newoff = off + delta;
   1266 	else if ((oldoff + delta) < (size + off))
   1267 		newoff = oldoff + delta;
   1268 	else
   1269 		newoff = (oldoff + delta) - size;
   1270 
   1271 	/* Note some interesting axioms */
   1272 	KASSERT((delta != 0) || (newoff == oldoff));
   1273 	KASSERT((delta == 0) || (newoff != 0));
   1274 	KASSERT((delta != (size)) || (newoff == oldoff));
   1275 
   1276 	/* Define acceptable ranges for output. */
   1277 	KASSERT((newoff == 0) || ((size_t)newoff >= off));
   1278 	KASSERT((size_t)newoff < (size + off));
   1279 	return newoff;
   1280 }
   1281 
   1282 /*
   1283  * wapbl_space_free(avail, head, tail)
   1284  *
   1285  *	Number of bytes free in a circular queue of avail total bytes,
   1286  *	in which everything from tail to head is used.
   1287  */
   1288 static inline size_t
   1289 wapbl_space_free(size_t avail, off_t head, off_t tail)
   1290 {
   1291 
   1292 	return avail - wapbl_space_used(avail, head, tail);
   1293 }
   1294 
   1295 /*
   1296  * wapbl_advance_head(size, off, delta, headp, tailp)
   1297  *
   1298  *	In a circular queue of size bytes starting at off, given the
   1299  *	old head and tail offsets *headp and *tailp, store the new head
   1300  *	and tail offsets in *headp and *tailp resulting from adding
   1301  *	delta bytes of data to the head.
   1302  */
   1303 static inline void
   1304 wapbl_advance_head(size_t size, size_t off, size_t delta, off_t *headp,
   1305 		   off_t *tailp)
   1306 {
   1307 	off_t head = *headp;
   1308 	off_t tail = *tailp;
   1309 
   1310 	KASSERT(delta <= wapbl_space_free(size, head, tail));
   1311 	head = wapbl_advance(size, off, head, delta);
   1312 	if ((tail == 0) && (head != 0))
   1313 		tail = off;
   1314 	*headp = head;
   1315 	*tailp = tail;
   1316 }
   1317 
   1318 /*
   1319  * wapbl_advance_tail(size, off, delta, headp, tailp)
   1320  *
   1321  *	In a circular queue of size bytes starting at off, given the
   1322  *	old head and tail offsets *headp and *tailp, store the new head
   1323  *	and tail offsets in *headp and *tailp resulting from removing
   1324  *	delta bytes of data from the tail.
   1325  */
   1326 static inline void
   1327 wapbl_advance_tail(size_t size, size_t off, size_t delta, off_t *headp,
   1328 		   off_t *tailp)
   1329 {
   1330 	off_t head = *headp;
   1331 	off_t tail = *tailp;
   1332 
   1333 	KASSERT(delta <= wapbl_space_used(size, head, tail));
   1334 	tail = wapbl_advance(size, off, tail, delta);
   1335 	if (head == tail) {
   1336 		head = tail = 0;
   1337 	}
   1338 	*headp = head;
   1339 	*tailp = tail;
   1340 }
   1341 
   1342 
   1343 /****************************************************************/
   1344 
   1345 /*
   1346  * wapbl_truncate(wl, minfree)
   1347  *
   1348  *	Wait until at least minfree bytes are available in the log.
   1349  *
   1350  *	If it was necessary to wait for writes to complete,
   1351  *	advance the circular queue tail to reflect the new write
   1352  *	completions and issue a write commit to the log.
   1353  *
   1354  *	=> Caller must hold wl->wl_rwlock writer lock.
   1355  */
   1356 static int
   1357 wapbl_truncate(struct wapbl *wl, size_t minfree)
   1358 {
   1359 	size_t delta;
   1360 	size_t avail;
   1361 	off_t head;
   1362 	off_t tail;
   1363 	int error = 0;
   1364 
   1365 	KASSERT(minfree <= (wl->wl_circ_size - wl->wl_reserved_bytes));
   1366 	KASSERT(rw_write_held(&wl->wl_rwlock));
   1367 
   1368 	mutex_enter(&wl->wl_mtx);
   1369 
   1370 	/*
   1371 	 * First check to see if we have to do a commit
   1372 	 * at all.
   1373 	 */
   1374 	avail = wapbl_space_free(wl->wl_circ_size, wl->wl_head, wl->wl_tail);
   1375 	if (minfree < avail) {
   1376 		mutex_exit(&wl->wl_mtx);
   1377 		return 0;
   1378 	}
   1379 	minfree -= avail;
   1380 	while ((wl->wl_error_count == 0) &&
   1381 	    (wl->wl_reclaimable_bytes < minfree)) {
   1382         	WAPBL_PRINTF(WAPBL_PRINT_TRUNCATE,
   1383                    ("wapbl_truncate: sleeping on %p wl=%p bytes=%zd "
   1384 		    "minfree=%zd\n",
   1385                     &wl->wl_reclaimable_bytes, wl, wl->wl_reclaimable_bytes,
   1386 		    minfree));
   1387 
   1388 		cv_wait(&wl->wl_reclaimable_cv, &wl->wl_mtx);
   1389 	}
   1390 	if (wl->wl_reclaimable_bytes < minfree) {
   1391 		KASSERT(wl->wl_error_count);
   1392 		/* XXX maybe get actual error from buffer instead someday? */
   1393 		error = EIO;
   1394 	}
   1395 	head = wl->wl_head;
   1396 	tail = wl->wl_tail;
   1397 	delta = wl->wl_reclaimable_bytes;
   1398 
   1399 	/* If all of of the entries are flushed, then be sure to keep
   1400 	 * the reserved bytes reserved.  Watch out for discarded transactions,
   1401 	 * which could leave more bytes reserved than are reclaimable.
   1402 	 */
   1403 	if (SIMPLEQ_EMPTY(&wl->wl_entries) &&
   1404 	    (delta >= wl->wl_reserved_bytes)) {
   1405 		delta -= wl->wl_reserved_bytes;
   1406 	}
   1407 	wapbl_advance_tail(wl->wl_circ_size, wl->wl_circ_off, delta, &head,
   1408 			   &tail);
   1409 	KDASSERT(wl->wl_reserved_bytes <=
   1410 		wapbl_space_used(wl->wl_circ_size, head, tail));
   1411 	mutex_exit(&wl->wl_mtx);
   1412 
   1413 	if (error)
   1414 		return error;
   1415 
   1416 	/*
   1417 	 * This is where head, tail and delta are unprotected
   1418 	 * from races against itself or flush.  This is ok since
   1419 	 * we only call this routine from inside flush itself.
   1420 	 *
   1421 	 * XXX: how can it race against itself when accessed only
   1422 	 * from behind the write-locked rwlock?
   1423 	 */
   1424 	error = wapbl_write_commit(wl, head, tail);
   1425 	if (error)
   1426 		return error;
   1427 
   1428 	wl->wl_head = head;
   1429 	wl->wl_tail = tail;
   1430 
   1431 	mutex_enter(&wl->wl_mtx);
   1432 	KASSERT(wl->wl_reclaimable_bytes >= delta);
   1433 	wl->wl_reclaimable_bytes -= delta;
   1434 	mutex_exit(&wl->wl_mtx);
   1435 	WAPBL_PRINTF(WAPBL_PRINT_TRUNCATE,
   1436 	    ("wapbl_truncate thread %d.%d truncating %zu bytes\n",
   1437 	    curproc->p_pid, curlwp->l_lid, delta));
   1438 
   1439 	return 0;
   1440 }
   1441 
   1442 /****************************************************************/
   1443 
   1444 void
   1445 wapbl_biodone(struct buf *bp)
   1446 {
   1447 	struct wapbl_entry *we = bp->b_private;
   1448 	struct wapbl *wl = we->we_wapbl;
   1449 #ifdef WAPBL_DEBUG_BUFBYTES
   1450 	const int bufsize = bp->b_bufsize;
   1451 #endif
   1452 
   1453 	/*
   1454 	 * Handle possible flushing of buffers after log has been
   1455 	 * decomissioned.
   1456 	 */
   1457 	if (!wl) {
   1458 		KASSERT(we->we_bufcount > 0);
   1459 		we->we_bufcount--;
   1460 #ifdef WAPBL_DEBUG_BUFBYTES
   1461 		KASSERT(we->we_unsynced_bufbytes >= bufsize);
   1462 		we->we_unsynced_bufbytes -= bufsize;
   1463 #endif
   1464 
   1465 		if (we->we_bufcount == 0) {
   1466 #ifdef WAPBL_DEBUG_BUFBYTES
   1467 			KASSERT(we->we_unsynced_bufbytes == 0);
   1468 #endif
   1469 			pool_put(&wapbl_entry_pool, we);
   1470 		}
   1471 
   1472 		brelse(bp, 0);
   1473 		return;
   1474 	}
   1475 
   1476 #ifdef ohbother
   1477 	KDASSERT(bp->b_oflags & BO_DONE);
   1478 	KDASSERT(!(bp->b_oflags & BO_DELWRI));
   1479 	KDASSERT(bp->b_flags & B_ASYNC);
   1480 	KDASSERT(bp->b_cflags & BC_BUSY);
   1481 	KDASSERT(!(bp->b_flags & B_LOCKED));
   1482 	KDASSERT(!(bp->b_flags & B_READ));
   1483 	KDASSERT(!(bp->b_cflags & BC_INVAL));
   1484 	KDASSERT(!(bp->b_cflags & BC_NOCACHE));
   1485 #endif
   1486 
   1487 	if (bp->b_error) {
   1488 		/*
   1489 		 * If an error occurs, it would be nice to leave the buffer
   1490 		 * as a delayed write on the LRU queue so that we can retry
   1491 		 * it later. But buffercache(9) can't handle dirty buffer
   1492 		 * reuse, so just mark the log permanently errored out.
   1493 		 */
   1494 		mutex_enter(&wl->wl_mtx);
   1495 		if (wl->wl_error_count == 0) {
   1496 			wl->wl_error_count++;
   1497 			cv_broadcast(&wl->wl_reclaimable_cv);
   1498 		}
   1499 		mutex_exit(&wl->wl_mtx);
   1500 	}
   1501 
   1502 	/*
   1503 	 * Release the buffer here. wapbl_flush() may wait for the
   1504 	 * log to become empty and we better unbusy the buffer before
   1505 	 * wapbl_flush() returns.
   1506 	 */
   1507 	brelse(bp, 0);
   1508 
   1509 	mutex_enter(&wl->wl_mtx);
   1510 
   1511 	KASSERT(we->we_bufcount > 0);
   1512 	we->we_bufcount--;
   1513 #ifdef WAPBL_DEBUG_BUFBYTES
   1514 	KASSERT(we->we_unsynced_bufbytes >= bufsize);
   1515 	we->we_unsynced_bufbytes -= bufsize;
   1516 	KASSERT(wl->wl_unsynced_bufbytes >= bufsize);
   1517 	wl->wl_unsynced_bufbytes -= bufsize;
   1518 #endif
   1519 	wl->wl_ev_metawrite.ev_count++;
   1520 
   1521 	/*
   1522 	 * If the current transaction can be reclaimed, start
   1523 	 * at the beginning and reclaim any consecutive reclaimable
   1524 	 * transactions.  If we successfully reclaim anything,
   1525 	 * then wakeup anyone waiting for the reclaim.
   1526 	 */
   1527 	if (we->we_bufcount == 0) {
   1528 		size_t delta = 0;
   1529 		int errcnt = 0;
   1530 #ifdef WAPBL_DEBUG_BUFBYTES
   1531 		KDASSERT(we->we_unsynced_bufbytes == 0);
   1532 #endif
   1533 		/*
   1534 		 * clear any posted error, since the buffer it came from
   1535 		 * has successfully flushed by now
   1536 		 */
   1537 		while ((we = SIMPLEQ_FIRST(&wl->wl_entries)) &&
   1538 		       (we->we_bufcount == 0)) {
   1539 			delta += we->we_reclaimable_bytes;
   1540 			if (we->we_error)
   1541 				errcnt++;
   1542 			SIMPLEQ_REMOVE_HEAD(&wl->wl_entries, we_entries);
   1543 			pool_put(&wapbl_entry_pool, we);
   1544 		}
   1545 
   1546 		if (delta) {
   1547 			wl->wl_reclaimable_bytes += delta;
   1548 			KASSERT(wl->wl_error_count >= errcnt);
   1549 			wl->wl_error_count -= errcnt;
   1550 			cv_broadcast(&wl->wl_reclaimable_cv);
   1551 		}
   1552 	}
   1553 
   1554 	mutex_exit(&wl->wl_mtx);
   1555 }
   1556 
   1557 /*
   1558  * wapbl_flush(wl, wait)
   1559  *
   1560  *	Flush pending block writes, deallocations, and inodes from
   1561  *	the current transaction in memory to the log on disk:
   1562  *
   1563  *	1. Call the file system's wl_flush callback to flush any
   1564  *	   per-file-system pending updates.
   1565  *	2. Wait for enough space in the log for the current transaction.
   1566  *	3. Synchronously write the new log records, advancing the
   1567  *	   circular queue head.
   1568  *	4. Issue the pending block writes asynchronously, now that they
   1569  *	   are recorded in the log and can be replayed after crash.
   1570  *	5. If wait is true, wait for all writes to complete and for the
   1571  *	   log to become empty.
   1572  *
   1573  *	On failure, call the file system's wl_flush_abort callback.
   1574  */
   1575 int
   1576 wapbl_flush(struct wapbl *wl, int waitfor)
   1577 {
   1578 	struct buf *bp;
   1579 	struct wapbl_entry *we;
   1580 	off_t off;
   1581 	off_t head;
   1582 	off_t tail;
   1583 	size_t delta = 0;
   1584 	size_t flushsize;
   1585 	size_t reserved;
   1586 	int error = 0;
   1587 
   1588 	/*
   1589 	 * Do a quick check to see if a full flush can be skipped
   1590 	 * This assumes that the flush callback does not need to be called
   1591 	 * unless there are other outstanding bufs.
   1592 	 */
   1593 	if (!waitfor) {
   1594 		size_t nbufs;
   1595 		mutex_enter(&wl->wl_mtx);	/* XXX need mutex here to
   1596 						   protect the KASSERTS */
   1597 		nbufs = wl->wl_bufcount;
   1598 		KASSERT((wl->wl_bufcount == 0) == (wl->wl_bufbytes == 0));
   1599 		KASSERT((wl->wl_bufcount == 0) == (wl->wl_bcount == 0));
   1600 		mutex_exit(&wl->wl_mtx);
   1601 		if (nbufs == 0)
   1602 			return 0;
   1603 	}
   1604 
   1605 	/*
   1606 	 * XXX we may consider using LK_UPGRADE here
   1607 	 * if we want to call flush from inside a transaction
   1608 	 */
   1609 	rw_enter(&wl->wl_rwlock, RW_WRITER);
   1610 	wl->wl_flush(wl->wl_mount, TAILQ_FIRST(&wl->wl_dealloclist));
   1611 
   1612 	/*
   1613 	 * Now that we are exclusively locked and the file system has
   1614 	 * issued any deferred block writes for this transaction, check
   1615 	 * whether there are any blocks to write to the log.  If not,
   1616 	 * skip waiting for space or writing any log entries.
   1617 	 *
   1618 	 * XXX Shouldn't this also check wl_dealloccnt and
   1619 	 * wl_inohashcnt?  Perhaps wl_dealloccnt doesn't matter if the
   1620 	 * file system didn't produce any blocks as a consequence of
   1621 	 * it, but the same does not seem to be so of wl_inohashcnt.
   1622 	 */
   1623 	if (wl->wl_bufcount == 0) {
   1624 		goto wait_out;
   1625 	}
   1626 
   1627 #if 0
   1628 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
   1629 		     ("wapbl_flush thread %d.%d flushing entries with "
   1630 		      "bufcount=%zu bufbytes=%zu\n",
   1631 		      curproc->p_pid, curlwp->l_lid, wl->wl_bufcount,
   1632 		      wl->wl_bufbytes));
   1633 #endif
   1634 
   1635 	/* Calculate amount of space needed to flush */
   1636 	flushsize = wapbl_transaction_len(wl);
   1637 	if (wapbl_verbose_commit) {
   1638 		struct timespec ts;
   1639 		getnanotime(&ts);
   1640 		printf("%s: %lld.%09ld this transaction = %zu bytes\n",
   1641 		    __func__, (long long)ts.tv_sec,
   1642 		    (long)ts.tv_nsec, flushsize);
   1643 	}
   1644 
   1645 	if (flushsize > (wl->wl_circ_size - wl->wl_reserved_bytes)) {
   1646 		/*
   1647 		 * XXX this could be handled more gracefully, perhaps place
   1648 		 * only a partial transaction in the log and allow the
   1649 		 * remaining to flush without the protection of the journal.
   1650 		 */
   1651 		panic("wapbl_flush: current transaction too big to flush");
   1652 	}
   1653 
   1654 	error = wapbl_truncate(wl, flushsize);
   1655 	if (error)
   1656 		goto out;
   1657 
   1658 	off = wl->wl_head;
   1659 	KASSERT((off == 0) || (off >= wl->wl_circ_off));
   1660 	KASSERT((off == 0) || (off < wl->wl_circ_off + wl->wl_circ_size));
   1661 	error = wapbl_write_blocks(wl, &off);
   1662 	if (error)
   1663 		goto out;
   1664 	error = wapbl_write_revocations(wl, &off);
   1665 	if (error)
   1666 		goto out;
   1667 	error = wapbl_write_inodes(wl, &off);
   1668 	if (error)
   1669 		goto out;
   1670 
   1671 	reserved = 0;
   1672 	if (wl->wl_inohashcnt)
   1673 		reserved = wapbl_transaction_inodes_len(wl);
   1674 
   1675 	head = wl->wl_head;
   1676 	tail = wl->wl_tail;
   1677 
   1678 	wapbl_advance_head(wl->wl_circ_size, wl->wl_circ_off, flushsize,
   1679 	    &head, &tail);
   1680 
   1681 	KASSERTMSG(head == off,
   1682 	    "lost head! head=%"PRIdMAX" tail=%" PRIdMAX
   1683 	    " off=%"PRIdMAX" flush=%zu",
   1684 	    (intmax_t)head, (intmax_t)tail, (intmax_t)off,
   1685 	    flushsize);
   1686 
   1687 	/* Opportunistically move the tail forward if we can */
   1688 	mutex_enter(&wl->wl_mtx);
   1689 	delta = wl->wl_reclaimable_bytes;
   1690 	mutex_exit(&wl->wl_mtx);
   1691 	wapbl_advance_tail(wl->wl_circ_size, wl->wl_circ_off, delta,
   1692 	    &head, &tail);
   1693 
   1694 	error = wapbl_write_commit(wl, head, tail);
   1695 	if (error)
   1696 		goto out;
   1697 
   1698 	we = pool_get(&wapbl_entry_pool, PR_WAITOK);
   1699 
   1700 #ifdef WAPBL_DEBUG_BUFBYTES
   1701 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
   1702 		("wapbl_flush: thread %d.%d head+=%zu tail+=%zu used=%zu"
   1703 		 " unsynced=%zu"
   1704 		 "\n\tbufcount=%zu bufbytes=%zu bcount=%zu deallocs=%d "
   1705 		 "inodes=%d\n",
   1706 		 curproc->p_pid, curlwp->l_lid, flushsize, delta,
   1707 		 wapbl_space_used(wl->wl_circ_size, head, tail),
   1708 		 wl->wl_unsynced_bufbytes, wl->wl_bufcount,
   1709 		 wl->wl_bufbytes, wl->wl_bcount, wl->wl_dealloccnt,
   1710 		 wl->wl_inohashcnt));
   1711 #else
   1712 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
   1713 		("wapbl_flush: thread %d.%d head+=%zu tail+=%zu used=%zu"
   1714 		 "\n\tbufcount=%zu bufbytes=%zu bcount=%zu deallocs=%d "
   1715 		 "inodes=%d\n",
   1716 		 curproc->p_pid, curlwp->l_lid, flushsize, delta,
   1717 		 wapbl_space_used(wl->wl_circ_size, head, tail),
   1718 		 wl->wl_bufcount, wl->wl_bufbytes, wl->wl_bcount,
   1719 		 wl->wl_dealloccnt, wl->wl_inohashcnt));
   1720 #endif
   1721 
   1722 
   1723 	mutex_enter(&bufcache_lock);
   1724 	mutex_enter(&wl->wl_mtx);
   1725 
   1726 	wl->wl_reserved_bytes = reserved;
   1727 	wl->wl_head = head;
   1728 	wl->wl_tail = tail;
   1729 	KASSERT(wl->wl_reclaimable_bytes >= delta);
   1730 	wl->wl_reclaimable_bytes -= delta;
   1731 	KDASSERT(wl->wl_dealloccnt == 0);
   1732 #ifdef WAPBL_DEBUG_BUFBYTES
   1733 	wl->wl_unsynced_bufbytes += wl->wl_bufbytes;
   1734 #endif
   1735 
   1736 	we->we_wapbl = wl;
   1737 	we->we_bufcount = wl->wl_bufcount;
   1738 #ifdef WAPBL_DEBUG_BUFBYTES
   1739 	we->we_unsynced_bufbytes = wl->wl_bufbytes;
   1740 #endif
   1741 	we->we_reclaimable_bytes = flushsize;
   1742 	we->we_error = 0;
   1743 	SIMPLEQ_INSERT_TAIL(&wl->wl_entries, we, we_entries);
   1744 
   1745 	/*
   1746 	 * this flushes bufs in reverse order than they were queued
   1747 	 * it shouldn't matter, but if we care we could use TAILQ instead.
   1748 	 * XXX Note they will get put on the lru queue when they flush
   1749 	 * so we might actually want to change this to preserve order.
   1750 	 */
   1751 	while ((bp = LIST_FIRST(&wl->wl_bufs)) != NULL) {
   1752 		if (bbusy(bp, 0, 0, &wl->wl_mtx)) {
   1753 			continue;
   1754 		}
   1755 		bp->b_iodone = wapbl_biodone;
   1756 		bp->b_private = we;
   1757 		bremfree(bp);
   1758 		wapbl_remove_buf_locked(wl, bp);
   1759 		mutex_exit(&wl->wl_mtx);
   1760 		mutex_exit(&bufcache_lock);
   1761 		bawrite(bp);
   1762 		mutex_enter(&bufcache_lock);
   1763 		mutex_enter(&wl->wl_mtx);
   1764 	}
   1765 	mutex_exit(&wl->wl_mtx);
   1766 	mutex_exit(&bufcache_lock);
   1767 
   1768 #if 0
   1769 	WAPBL_PRINTF(WAPBL_PRINT_FLUSH,
   1770 		     ("wapbl_flush thread %d.%d done flushing entries...\n",
   1771 		     curproc->p_pid, curlwp->l_lid));
   1772 #endif
   1773 
   1774  wait_out:
   1775 
   1776 	/*
   1777 	 * If the waitfor flag is set, don't return until everything is
   1778 	 * fully flushed and the on disk log is empty.
   1779 	 */
   1780 	if (waitfor) {
   1781 		error = wapbl_truncate(wl, wl->wl_circ_size -
   1782 			wl->wl_reserved_bytes);
   1783 	}
   1784 
   1785  out:
   1786 	if (error) {
   1787 		wl->wl_flush_abort(wl->wl_mount,
   1788 		    TAILQ_FIRST(&wl->wl_dealloclist));
   1789 	}
   1790 
   1791 #ifdef WAPBL_DEBUG_PRINT
   1792 	if (error) {
   1793 		pid_t pid = -1;
   1794 		lwpid_t lid = -1;
   1795 		if (curproc)
   1796 			pid = curproc->p_pid;
   1797 		if (curlwp)
   1798 			lid = curlwp->l_lid;
   1799 		mutex_enter(&wl->wl_mtx);
   1800 #ifdef WAPBL_DEBUG_BUFBYTES
   1801 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
   1802 		    ("wapbl_flush: thread %d.%d aborted flush: "
   1803 		    "error = %d\n"
   1804 		    "\tbufcount=%zu bufbytes=%zu bcount=%zu "
   1805 		    "deallocs=%d inodes=%d\n"
   1806 		    "\terrcnt = %d, reclaimable=%zu reserved=%zu "
   1807 		    "unsynced=%zu\n",
   1808 		    pid, lid, error, wl->wl_bufcount,
   1809 		    wl->wl_bufbytes, wl->wl_bcount,
   1810 		    wl->wl_dealloccnt, wl->wl_inohashcnt,
   1811 		    wl->wl_error_count, wl->wl_reclaimable_bytes,
   1812 		    wl->wl_reserved_bytes, wl->wl_unsynced_bufbytes));
   1813 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
   1814 			WAPBL_PRINTF(WAPBL_PRINT_ERROR,
   1815 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
   1816 			     "error = %d, unsynced = %zu\n",
   1817 			     we->we_bufcount, we->we_reclaimable_bytes,
   1818 			     we->we_error, we->we_unsynced_bufbytes));
   1819 		}
   1820 #else
   1821 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
   1822 		    ("wapbl_flush: thread %d.%d aborted flush: "
   1823 		     "error = %d\n"
   1824 		     "\tbufcount=%zu bufbytes=%zu bcount=%zu "
   1825 		     "deallocs=%d inodes=%d\n"
   1826 		     "\terrcnt = %d, reclaimable=%zu reserved=%zu\n",
   1827 		     pid, lid, error, wl->wl_bufcount,
   1828 		     wl->wl_bufbytes, wl->wl_bcount,
   1829 		     wl->wl_dealloccnt, wl->wl_inohashcnt,
   1830 		     wl->wl_error_count, wl->wl_reclaimable_bytes,
   1831 		     wl->wl_reserved_bytes));
   1832 		SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
   1833 			WAPBL_PRINTF(WAPBL_PRINT_ERROR,
   1834 			    ("\tentry: bufcount = %zu, reclaimable = %zu, "
   1835 			     "error = %d\n", we->we_bufcount,
   1836 			     we->we_reclaimable_bytes, we->we_error));
   1837 		}
   1838 #endif
   1839 		mutex_exit(&wl->wl_mtx);
   1840 	}
   1841 #endif
   1842 
   1843 	rw_exit(&wl->wl_rwlock);
   1844 	return error;
   1845 }
   1846 
   1847 /****************************************************************/
   1848 
   1849 void
   1850 wapbl_jlock_assert(struct wapbl *wl)
   1851 {
   1852 
   1853 	KASSERT(rw_lock_held(&wl->wl_rwlock));
   1854 }
   1855 
   1856 void
   1857 wapbl_junlock_assert(struct wapbl *wl)
   1858 {
   1859 
   1860 	KASSERT(!rw_write_held(&wl->wl_rwlock));
   1861 }
   1862 
   1863 /****************************************************************/
   1864 
   1865 /* locks missing */
   1866 void
   1867 wapbl_print(struct wapbl *wl,
   1868 		int full,
   1869 		void (*pr)(const char *, ...))
   1870 {
   1871 	struct buf *bp;
   1872 	struct wapbl_entry *we;
   1873 	(*pr)("wapbl %p", wl);
   1874 	(*pr)("\nlogvp = %p, devvp = %p, logpbn = %"PRId64"\n",
   1875 	      wl->wl_logvp, wl->wl_devvp, wl->wl_logpbn);
   1876 	(*pr)("circ = %zu, header = %zu, head = %"PRIdMAX" tail = %"PRIdMAX"\n",
   1877 	      wl->wl_circ_size, wl->wl_circ_off,
   1878 	      (intmax_t)wl->wl_head, (intmax_t)wl->wl_tail);
   1879 	(*pr)("fs_dev_bshift = %d, log_dev_bshift = %d\n",
   1880 	      wl->wl_log_dev_bshift, wl->wl_fs_dev_bshift);
   1881 #ifdef WAPBL_DEBUG_BUFBYTES
   1882 	(*pr)("bufcount = %zu, bufbytes = %zu bcount = %zu reclaimable = %zu "
   1883 	      "reserved = %zu errcnt = %d unsynced = %zu\n",
   1884 	      wl->wl_bufcount, wl->wl_bufbytes, wl->wl_bcount,
   1885 	      wl->wl_reclaimable_bytes, wl->wl_reserved_bytes,
   1886 				wl->wl_error_count, wl->wl_unsynced_bufbytes);
   1887 #else
   1888 	(*pr)("bufcount = %zu, bufbytes = %zu bcount = %zu reclaimable = %zu "
   1889 	      "reserved = %zu errcnt = %d\n", wl->wl_bufcount, wl->wl_bufbytes,
   1890 	      wl->wl_bcount, wl->wl_reclaimable_bytes, wl->wl_reserved_bytes,
   1891 				wl->wl_error_count);
   1892 #endif
   1893 	(*pr)("\tdealloccnt = %d, dealloclim = %d\n",
   1894 	      wl->wl_dealloccnt, wl->wl_dealloclim);
   1895 	(*pr)("\tinohashcnt = %d, inohashmask = 0x%08x\n",
   1896 	      wl->wl_inohashcnt, wl->wl_inohashmask);
   1897 	(*pr)("entries:\n");
   1898 	SIMPLEQ_FOREACH(we, &wl->wl_entries, we_entries) {
   1899 #ifdef WAPBL_DEBUG_BUFBYTES
   1900 		(*pr)("\tbufcount = %zu, reclaimable = %zu, error = %d, "
   1901 		      "unsynced = %zu\n",
   1902 		      we->we_bufcount, we->we_reclaimable_bytes,
   1903 		      we->we_error, we->we_unsynced_bufbytes);
   1904 #else
   1905 		(*pr)("\tbufcount = %zu, reclaimable = %zu, error = %d\n",
   1906 		      we->we_bufcount, we->we_reclaimable_bytes, we->we_error);
   1907 #endif
   1908 	}
   1909 	if (full) {
   1910 		int cnt = 0;
   1911 		(*pr)("bufs =");
   1912 		LIST_FOREACH(bp, &wl->wl_bufs, b_wapbllist) {
   1913 			if (!LIST_NEXT(bp, b_wapbllist)) {
   1914 				(*pr)(" %p", bp);
   1915 			} else if ((++cnt % 6) == 0) {
   1916 				(*pr)(" %p,\n\t", bp);
   1917 			} else {
   1918 				(*pr)(" %p,", bp);
   1919 			}
   1920 		}
   1921 		(*pr)("\n");
   1922 
   1923 		(*pr)("dealloced blks = ");
   1924 		{
   1925 			struct wapbl_dealloc *wd;
   1926 			cnt = 0;
   1927 			TAILQ_FOREACH(wd, &wl->wl_dealloclist, wd_entries) {
   1928 				(*pr)(" %"PRId64":%d,",
   1929 				      wd->wd_blkno,
   1930 				      wd->wd_len);
   1931 				if ((++cnt % 4) == 0) {
   1932 					(*pr)("\n\t");
   1933 				}
   1934 			}
   1935 		}
   1936 		(*pr)("\n");
   1937 
   1938 		(*pr)("registered inodes = ");
   1939 		{
   1940 			int i;
   1941 			cnt = 0;
   1942 			for (i = 0; i <= wl->wl_inohashmask; i++) {
   1943 				struct wapbl_ino_head *wih;
   1944 				struct wapbl_ino *wi;
   1945 
   1946 				wih = &wl->wl_inohash[i];
   1947 				LIST_FOREACH(wi, wih, wi_hash) {
   1948 					if (wi->wi_ino == 0)
   1949 						continue;
   1950 					(*pr)(" %"PRIu64"/0%06"PRIo32",",
   1951 					    wi->wi_ino, wi->wi_mode);
   1952 					if ((++cnt % 4) == 0) {
   1953 						(*pr)("\n\t");
   1954 					}
   1955 				}
   1956 			}
   1957 			(*pr)("\n");
   1958 		}
   1959 	}
   1960 }
   1961 
   1962 #if defined(WAPBL_DEBUG) || defined(DDB)
   1963 void
   1964 wapbl_dump(struct wapbl *wl)
   1965 {
   1966 #if defined(WAPBL_DEBUG)
   1967 	if (!wl)
   1968 		wl = wapbl_debug_wl;
   1969 #endif
   1970 	if (!wl)
   1971 		return;
   1972 	wapbl_print(wl, 1, printf);
   1973 }
   1974 #endif
   1975 
   1976 /****************************************************************/
   1977 
   1978 int
   1979 wapbl_register_deallocation(struct wapbl *wl, daddr_t blk, int len, bool force,
   1980     void **cookiep)
   1981 {
   1982 	struct wapbl_dealloc *wd;
   1983 	int error = 0;
   1984 
   1985 	wapbl_jlock_assert(wl);
   1986 
   1987 	mutex_enter(&wl->wl_mtx);
   1988 
   1989 	if (__predict_false(wl->wl_dealloccnt >= wl->wl_dealloclim)) {
   1990 		if (!force) {
   1991 			error = EAGAIN;
   1992 			goto out;
   1993 		}
   1994 
   1995 		/*
   1996 		 * Forced registration can only be used when:
   1997 		 * 1) the caller can't cope with failure
   1998 		 * 2) the path can be triggered only bounded, small
   1999 		 *    times per transaction
   2000 		 * If this is not fullfilled, and the path would be triggered
   2001 		 * many times, this could overflow maximum transaction size
   2002 		 * and panic later.
   2003 		 */
   2004 		printf("%s: forced dealloc registration over limit: %d >= %d\n",
   2005 			wl->wl_mount->mnt_stat.f_mntonname,
   2006 			wl->wl_dealloccnt, wl->wl_dealloclim);
   2007 	}
   2008 
   2009 	wl->wl_dealloccnt++;
   2010 	mutex_exit(&wl->wl_mtx);
   2011 
   2012 	wd = pool_get(&wapbl_dealloc_pool, PR_WAITOK);
   2013 	wd->wd_blkno = blk;
   2014 	wd->wd_len = len;
   2015 
   2016 	mutex_enter(&wl->wl_mtx);
   2017 	TAILQ_INSERT_TAIL(&wl->wl_dealloclist, wd, wd_entries);
   2018 
   2019 	if (cookiep)
   2020 		*cookiep = wd;
   2021 
   2022  out:
   2023 	mutex_exit(&wl->wl_mtx);
   2024 
   2025 	WAPBL_PRINTF(WAPBL_PRINT_ALLOC,
   2026 	    ("wapbl_register_deallocation: blk=%"PRId64" len=%d error=%d\n",
   2027 	    blk, len, error));
   2028 
   2029 	return error;
   2030 }
   2031 
   2032 static void
   2033 wapbl_deallocation_free(struct wapbl *wl, struct wapbl_dealloc *wd,
   2034 	bool locked)
   2035 {
   2036 	KASSERT(!locked
   2037 	    || rw_lock_held(&wl->wl_rwlock) || mutex_owned(&wl->wl_mtx));
   2038 
   2039 	if (!locked)
   2040 		mutex_enter(&wl->wl_mtx);
   2041 
   2042 	TAILQ_REMOVE(&wl->wl_dealloclist, wd, wd_entries);
   2043 	wl->wl_dealloccnt--;
   2044 
   2045 	if (!locked)
   2046 		mutex_exit(&wl->wl_mtx);
   2047 
   2048 	pool_put(&wapbl_dealloc_pool, wd);
   2049 }
   2050 
   2051 void
   2052 wapbl_unregister_deallocation(struct wapbl *wl, void *cookie)
   2053 {
   2054 	KASSERT(cookie != NULL);
   2055 	wapbl_deallocation_free(wl, cookie, false);
   2056 }
   2057 
   2058 /****************************************************************/
   2059 
   2060 static void
   2061 wapbl_inodetrk_init(struct wapbl *wl, u_int size)
   2062 {
   2063 
   2064 	wl->wl_inohash = hashinit(size, HASH_LIST, true, &wl->wl_inohashmask);
   2065 	if (atomic_inc_uint_nv(&wapbl_ino_pool_refcount) == 1) {
   2066 		pool_init(&wapbl_ino_pool, sizeof(struct wapbl_ino), 0, 0, 0,
   2067 		    "wapblinopl", &pool_allocator_nointr, IPL_NONE);
   2068 	}
   2069 }
   2070 
   2071 static void
   2072 wapbl_inodetrk_free(struct wapbl *wl)
   2073 {
   2074 
   2075 	/* XXX this KASSERT needs locking/mutex analysis */
   2076 	KASSERT(wl->wl_inohashcnt == 0);
   2077 	hashdone(wl->wl_inohash, HASH_LIST, wl->wl_inohashmask);
   2078 	if (atomic_dec_uint_nv(&wapbl_ino_pool_refcount) == 0) {
   2079 		pool_destroy(&wapbl_ino_pool);
   2080 	}
   2081 }
   2082 
   2083 static struct wapbl_ino *
   2084 wapbl_inodetrk_get(struct wapbl *wl, ino_t ino)
   2085 {
   2086 	struct wapbl_ino_head *wih;
   2087 	struct wapbl_ino *wi;
   2088 
   2089 	KASSERT(mutex_owned(&wl->wl_mtx));
   2090 
   2091 	wih = &wl->wl_inohash[ino & wl->wl_inohashmask];
   2092 	LIST_FOREACH(wi, wih, wi_hash) {
   2093 		if (ino == wi->wi_ino)
   2094 			return wi;
   2095 	}
   2096 	return 0;
   2097 }
   2098 
   2099 void
   2100 wapbl_register_inode(struct wapbl *wl, ino_t ino, mode_t mode)
   2101 {
   2102 	struct wapbl_ino_head *wih;
   2103 	struct wapbl_ino *wi;
   2104 
   2105 	wi = pool_get(&wapbl_ino_pool, PR_WAITOK);
   2106 
   2107 	mutex_enter(&wl->wl_mtx);
   2108 	if (wapbl_inodetrk_get(wl, ino) == NULL) {
   2109 		wi->wi_ino = ino;
   2110 		wi->wi_mode = mode;
   2111 		wih = &wl->wl_inohash[ino & wl->wl_inohashmask];
   2112 		LIST_INSERT_HEAD(wih, wi, wi_hash);
   2113 		wl->wl_inohashcnt++;
   2114 		WAPBL_PRINTF(WAPBL_PRINT_INODE,
   2115 		    ("wapbl_register_inode: ino=%"PRId64"\n", ino));
   2116 		mutex_exit(&wl->wl_mtx);
   2117 	} else {
   2118 		mutex_exit(&wl->wl_mtx);
   2119 		pool_put(&wapbl_ino_pool, wi);
   2120 	}
   2121 }
   2122 
   2123 void
   2124 wapbl_unregister_inode(struct wapbl *wl, ino_t ino, mode_t mode)
   2125 {
   2126 	struct wapbl_ino *wi;
   2127 
   2128 	mutex_enter(&wl->wl_mtx);
   2129 	wi = wapbl_inodetrk_get(wl, ino);
   2130 	if (wi) {
   2131 		WAPBL_PRINTF(WAPBL_PRINT_INODE,
   2132 		    ("wapbl_unregister_inode: ino=%"PRId64"\n", ino));
   2133 		KASSERT(wl->wl_inohashcnt > 0);
   2134 		wl->wl_inohashcnt--;
   2135 		LIST_REMOVE(wi, wi_hash);
   2136 		mutex_exit(&wl->wl_mtx);
   2137 
   2138 		pool_put(&wapbl_ino_pool, wi);
   2139 	} else {
   2140 		mutex_exit(&wl->wl_mtx);
   2141 	}
   2142 }
   2143 
   2144 /****************************************************************/
   2145 
   2146 /*
   2147  * wapbl_transaction_inodes_len(wl)
   2148  *
   2149  *	Calculate the number of bytes required for inode registration
   2150  *	log records in wl.
   2151  */
   2152 static inline size_t
   2153 wapbl_transaction_inodes_len(struct wapbl *wl)
   2154 {
   2155 	int blocklen = 1<<wl->wl_log_dev_bshift;
   2156 	int iph;
   2157 
   2158 	/* Calculate number of inodes described in a inodelist header */
   2159 	iph = (blocklen - offsetof(struct wapbl_wc_inodelist, wc_inodes)) /
   2160 	    sizeof(((struct wapbl_wc_inodelist *)0)->wc_inodes[0]);
   2161 
   2162 	KASSERT(iph > 0);
   2163 
   2164 	return MAX(1, howmany(wl->wl_inohashcnt, iph)) * blocklen;
   2165 }
   2166 
   2167 
   2168 /*
   2169  * wapbl_transaction_len(wl)
   2170  *
   2171  *	Calculate number of bytes required for all log records in wl.
   2172  */
   2173 static size_t
   2174 wapbl_transaction_len(struct wapbl *wl)
   2175 {
   2176 	int blocklen = 1<<wl->wl_log_dev_bshift;
   2177 	size_t len;
   2178 
   2179 	/* Calculate number of blocks described in a blocklist header */
   2180 	len = wl->wl_bcount;
   2181 	len += howmany(wl->wl_bufcount, wl->wl_brperjblock) * blocklen;
   2182 	len += howmany(wl->wl_dealloccnt, wl->wl_brperjblock) * blocklen;
   2183 	len += wapbl_transaction_inodes_len(wl);
   2184 
   2185 	return len;
   2186 }
   2187 
   2188 /*
   2189  * wapbl_cache_sync(wl, msg)
   2190  *
   2191  *	Issue DIOCCACHESYNC to wl->wl_devvp.
   2192  *
   2193  *	If sysctl(vfs.wapbl.verbose_commit) >= 2, print a message
   2194  *	including msg about the duration of the cache sync.
   2195  */
   2196 static int
   2197 wapbl_cache_sync(struct wapbl *wl, const char *msg)
   2198 {
   2199 	const bool verbose = wapbl_verbose_commit >= 2;
   2200 	struct bintime start_time;
   2201 	int force = 1;
   2202 	int error;
   2203 
   2204 	if (!wapbl_flush_disk_cache) {
   2205 		return 0;
   2206 	}
   2207 	if (verbose) {
   2208 		bintime(&start_time);
   2209 	}
   2210 	error = VOP_IOCTL(wl->wl_devvp, DIOCCACHESYNC, &force,
   2211 	    FWRITE, FSCRED);
   2212 	if (error) {
   2213 		WAPBL_PRINTF(WAPBL_PRINT_ERROR,
   2214 		    ("wapbl_cache_sync: DIOCCACHESYNC on dev 0x%jx "
   2215 		    "returned %d\n", (uintmax_t)wl->wl_devvp->v_rdev, error));
   2216 	}
   2217 	if (verbose) {
   2218 		struct bintime d;
   2219 		struct timespec ts;
   2220 
   2221 		bintime(&d);
   2222 		bintime_sub(&d, &start_time);
   2223 		bintime2timespec(&d, &ts);
   2224 		printf("wapbl_cache_sync: %s: dev 0x%jx %ju.%09lu\n",
   2225 		    msg, (uintmax_t)wl->wl_devvp->v_rdev,
   2226 		    (uintmax_t)ts.tv_sec, ts.tv_nsec);
   2227 	}
   2228 
   2229 	wl->wl_ev_cacheflush.ev_count++;
   2230 
   2231 	return error;
   2232 }
   2233 
   2234 /*
   2235  * wapbl_write_commit(wl, head, tail)
   2236  *
   2237  *	Issue a disk cache sync to wait for all pending writes to the
   2238  *	log to complete, and then synchronously commit the current
   2239  *	circular queue head and tail to the log, in the next of two
   2240  *	locations for commit headers on disk.
   2241  *
   2242  *	Increment the generation number.  If the generation number
   2243  *	rolls over to zero, then a subsequent commit would appear to
   2244  *	have an older generation than this one -- in that case, issue a
   2245  *	duplicate commit to avoid this.
   2246  *
   2247  *	=> Caller must have exclusive access to wl, either by holding
   2248  *	wl->wl_rwlock for writer or by being wapbl_start before anyone
   2249  *	else has seen wl.
   2250  */
   2251 static int
   2252 wapbl_write_commit(struct wapbl *wl, off_t head, off_t tail)
   2253 {
   2254 	struct wapbl_wc_header *wc = wl->wl_wc_header;
   2255 	struct timespec ts;
   2256 	int error;
   2257 	daddr_t pbn;
   2258 
   2259 	error = wapbl_buffered_flush(wl);
   2260 	if (error)
   2261 		return error;
   2262 	/*
   2263 	 * flush disk cache to ensure that blocks we've written are actually
   2264 	 * written to the stable storage before the commit header.
   2265 	 *
   2266 	 * XXX Calc checksum here, instead we do this for now
   2267 	 */
   2268 	wapbl_cache_sync(wl, "1");
   2269 
   2270 	wc->wc_head = head;
   2271 	wc->wc_tail = tail;
   2272 	wc->wc_checksum = 0;
   2273 	wc->wc_version = 1;
   2274 	getnanotime(&ts);
   2275 	wc->wc_time = ts.tv_sec;
   2276 	wc->wc_timensec = ts.tv_nsec;
   2277 
   2278 	WAPBL_PRINTF(WAPBL_PRINT_WRITE,
   2279 	    ("wapbl_write_commit: head = %"PRIdMAX "tail = %"PRIdMAX"\n",
   2280 	    (intmax_t)head, (intmax_t)tail));
   2281 
   2282 	/*
   2283 	 * write the commit header.
   2284 	 *
   2285 	 * XXX if generation will rollover, then first zero
   2286 	 * over second commit header before trying to write both headers.
   2287 	 */
   2288 
   2289 	pbn = wl->wl_logpbn + (wc->wc_generation % 2);
   2290 #ifdef _KERNEL
   2291 	pbn = btodb(pbn << wc->wc_log_dev_bshift);
   2292 #endif
   2293 	error = wapbl_buffered_write(wc, wc->wc_len, wl, pbn);
   2294 	if (error)
   2295 		return error;
   2296 	error = wapbl_buffered_flush(wl);
   2297 	if (error)
   2298 		return error;
   2299 
   2300 	/*
   2301 	 * flush disk cache to ensure that the commit header is actually
   2302 	 * written before meta data blocks.
   2303 	 */
   2304 	wapbl_cache_sync(wl, "2");
   2305 
   2306 	/*
   2307 	 * If the generation number was zero, write it out a second time.
   2308 	 * This handles initialization and generation number rollover
   2309 	 */
   2310 	if (wc->wc_generation++ == 0) {
   2311 		error = wapbl_write_commit(wl, head, tail);
   2312 		/*
   2313 		 * This panic should be able to be removed if we do the
   2314 		 * zero'ing mentioned above, and we are certain to roll
   2315 		 * back generation number on failure.
   2316 		 */
   2317 		if (error)
   2318 			panic("wapbl_write_commit: error writing duplicate "
   2319 			      "log header: %d", error);
   2320 	}
   2321 
   2322 	wl->wl_ev_commit.ev_count++;
   2323 
   2324 	return 0;
   2325 }
   2326 
   2327 /*
   2328  * wapbl_write_blocks(wl, offp)
   2329  *
   2330  *	Write all pending physical blocks in the current transaction
   2331  *	from wapbl_add_buf to the log on disk, adding to the circular
   2332  *	queue head at byte offset *offp, and returning the new head's
   2333  *	byte offset in *offp.
   2334  */
   2335 static int
   2336 wapbl_write_blocks(struct wapbl *wl, off_t *offp)
   2337 {
   2338 	struct wapbl_wc_blocklist *wc =
   2339 	    (struct wapbl_wc_blocklist *)wl->wl_wc_scratch;
   2340 	int blocklen = 1<<wl->wl_log_dev_bshift;
   2341 	struct buf *bp;
   2342 	off_t off = *offp;
   2343 	int error;
   2344 	size_t padding;
   2345 
   2346 	KASSERT(rw_write_held(&wl->wl_rwlock));
   2347 
   2348 	bp = LIST_FIRST(&wl->wl_bufs);
   2349 
   2350 	while (bp) {
   2351 		int cnt;
   2352 		struct buf *obp = bp;
   2353 
   2354 		KASSERT(bp->b_flags & B_LOCKED);
   2355 
   2356 		wc->wc_type = WAPBL_WC_BLOCKS;
   2357 		wc->wc_len = blocklen;
   2358 		wc->wc_blkcount = 0;
   2359 		while (bp && (wc->wc_blkcount < wl->wl_brperjblock)) {
   2360 			/*
   2361 			 * Make sure all the physical block numbers are up to
   2362 			 * date.  If this is not always true on a given
   2363 			 * filesystem, then VOP_BMAP must be called.  We
   2364 			 * could call VOP_BMAP here, or else in the filesystem
   2365 			 * specific flush callback, although neither of those
   2366 			 * solutions allow us to take the vnode lock.  If a
   2367 			 * filesystem requires that we must take the vnode lock
   2368 			 * to call VOP_BMAP, then we can probably do it in
   2369 			 * bwrite when the vnode lock should already be held
   2370 			 * by the invoking code.
   2371 			 */
   2372 			KASSERT((bp->b_vp->v_type == VBLK) ||
   2373 				 (bp->b_blkno != bp->b_lblkno));
   2374 			KASSERT(bp->b_blkno > 0);
   2375 
   2376 			wc->wc_blocks[wc->wc_blkcount].wc_daddr = bp->b_blkno;
   2377 			wc->wc_blocks[wc->wc_blkcount].wc_dlen = bp->b_bcount;
   2378 			wc->wc_len += bp->b_bcount;
   2379 			wc->wc_blkcount++;
   2380 			bp = LIST_NEXT(bp, b_wapbllist);
   2381 		}
   2382 		if (wc->wc_len % blocklen != 0) {
   2383 			padding = blocklen - wc->wc_len % blocklen;
   2384 			wc->wc_len += padding;
   2385 		} else {
   2386 			padding = 0;
   2387 		}
   2388 
   2389 		WAPBL_PRINTF(WAPBL_PRINT_WRITE,
   2390 		    ("wapbl_write_blocks: len = %u (padding %zu) off = %"PRIdMAX"\n",
   2391 		    wc->wc_len, padding, (intmax_t)off));
   2392 
   2393 		error = wapbl_circ_write(wl, wc, blocklen, &off);
   2394 		if (error)
   2395 			return error;
   2396 		bp = obp;
   2397 		cnt = 0;
   2398 		while (bp && (cnt++ < wl->wl_brperjblock)) {
   2399 			error = wapbl_circ_write(wl, bp->b_data,
   2400 			    bp->b_bcount, &off);
   2401 			if (error)
   2402 				return error;
   2403 			bp = LIST_NEXT(bp, b_wapbllist);
   2404 		}
   2405 		if (padding) {
   2406 			void *zero;
   2407 
   2408 			zero = wapbl_alloc(padding);
   2409 			memset(zero, 0, padding);
   2410 			error = wapbl_circ_write(wl, zero, padding, &off);
   2411 			wapbl_free(zero, padding);
   2412 			if (error)
   2413 				return error;
   2414 		}
   2415 	}
   2416 	*offp = off;
   2417 	return 0;
   2418 }
   2419 
   2420 /*
   2421  * wapbl_write_revocations(wl, offp)
   2422  *
   2423  *	Write all pending deallocations in the current transaction from
   2424  *	wapbl_register_deallocation to the log on disk, adding to the
   2425  *	circular queue's head at byte offset *offp, and returning the
   2426  *	new head's byte offset in *offp.
   2427  */
   2428 static int
   2429 wapbl_write_revocations(struct wapbl *wl, off_t *offp)
   2430 {
   2431 	struct wapbl_wc_blocklist *wc =
   2432 	    (struct wapbl_wc_blocklist *)wl->wl_wc_scratch;
   2433 	struct wapbl_dealloc *wd, *lwd;
   2434 	int blocklen = 1<<wl->wl_log_dev_bshift;
   2435 	off_t off = *offp;
   2436 	int error;
   2437 
   2438 	KASSERT(rw_write_held(&wl->wl_rwlock));
   2439 
   2440 	if (wl->wl_dealloccnt == 0)
   2441 		return 0;
   2442 
   2443 	while ((wd = TAILQ_FIRST(&wl->wl_dealloclist)) != NULL) {
   2444 		wc->wc_type = WAPBL_WC_REVOCATIONS;
   2445 		wc->wc_len = blocklen;
   2446 		wc->wc_blkcount = 0;
   2447 		while (wd && (wc->wc_blkcount < wl->wl_brperjblock)) {
   2448 			wc->wc_blocks[wc->wc_blkcount].wc_daddr =
   2449 			    wd->wd_blkno;
   2450 			wc->wc_blocks[wc->wc_blkcount].wc_dlen =
   2451 			    wd->wd_len;
   2452 			wc->wc_blkcount++;
   2453 
   2454 			wd = TAILQ_NEXT(wd, wd_entries);
   2455 		}
   2456 		WAPBL_PRINTF(WAPBL_PRINT_WRITE,
   2457 		    ("wapbl_write_revocations: len = %u off = %"PRIdMAX"\n",
   2458 		    wc->wc_len, (intmax_t)off));
   2459 		error = wapbl_circ_write(wl, wc, blocklen, &off);
   2460 		if (error)
   2461 			return error;
   2462 
   2463 		/* free all successfully written deallocs */
   2464 		lwd = wd;
   2465 		while ((wd = TAILQ_FIRST(&wl->wl_dealloclist)) != NULL) {
   2466 			if (wd == lwd)
   2467 				break;
   2468 			wapbl_deallocation_free(wl, wd, true);
   2469 		}
   2470 	}
   2471 	*offp = off;
   2472 	return 0;
   2473 }
   2474 
   2475 /*
   2476  * wapbl_write_inodes(wl, offp)
   2477  *
   2478  *	Write all pending inode allocations in the current transaction
   2479  *	from wapbl_register_inode to the log on disk, adding to the
   2480  *	circular queue's head at byte offset *offp and returning the
   2481  *	new head's byte offset in *offp.
   2482  */
   2483 static int
   2484 wapbl_write_inodes(struct wapbl *wl, off_t *offp)
   2485 {
   2486 	struct wapbl_wc_inodelist *wc =
   2487 	    (struct wapbl_wc_inodelist *)wl->wl_wc_scratch;
   2488 	int i;
   2489 	int blocklen = 1 << wl->wl_log_dev_bshift;
   2490 	off_t off = *offp;
   2491 	int error;
   2492 
   2493 	struct wapbl_ino_head *wih;
   2494 	struct wapbl_ino *wi;
   2495 	int iph;
   2496 
   2497 	KASSERT(rw_write_held(&wl->wl_rwlock));
   2498 
   2499 	iph = (blocklen - offsetof(struct wapbl_wc_inodelist, wc_inodes)) /
   2500 	    sizeof(((struct wapbl_wc_inodelist *)0)->wc_inodes[0]);
   2501 
   2502 	i = 0;
   2503 	wih = &wl->wl_inohash[0];
   2504 	wi = 0;
   2505 	do {
   2506 		wc->wc_type = WAPBL_WC_INODES;
   2507 		wc->wc_len = blocklen;
   2508 		wc->wc_inocnt = 0;
   2509 		wc->wc_clear = (i == 0);
   2510 		while ((i < wl->wl_inohashcnt) && (wc->wc_inocnt < iph)) {
   2511 			while (!wi) {
   2512 				KASSERT((wih - &wl->wl_inohash[0])
   2513 				    <= wl->wl_inohashmask);
   2514 				wi = LIST_FIRST(wih++);
   2515 			}
   2516 			wc->wc_inodes[wc->wc_inocnt].wc_inumber = wi->wi_ino;
   2517 			wc->wc_inodes[wc->wc_inocnt].wc_imode = wi->wi_mode;
   2518 			wc->wc_inocnt++;
   2519 			i++;
   2520 			wi = LIST_NEXT(wi, wi_hash);
   2521 		}
   2522 		WAPBL_PRINTF(WAPBL_PRINT_WRITE,
   2523 		    ("wapbl_write_inodes: len = %u off = %"PRIdMAX"\n",
   2524 		    wc->wc_len, (intmax_t)off));
   2525 		error = wapbl_circ_write(wl, wc, blocklen, &off);
   2526 		if (error)
   2527 			return error;
   2528 	} while (i < wl->wl_inohashcnt);
   2529 
   2530 	*offp = off;
   2531 	return 0;
   2532 }
   2533 
   2534 #endif /* _KERNEL */
   2535 
   2536 /****************************************************************/
   2537 
   2538 struct wapbl_blk {
   2539 	LIST_ENTRY(wapbl_blk) wb_hash;
   2540 	daddr_t wb_blk;
   2541 	off_t wb_off; /* Offset of this block in the log */
   2542 };
   2543 #define	WAPBL_BLKPOOL_MIN 83
   2544 
   2545 static void
   2546 wapbl_blkhash_init(struct wapbl_replay *wr, u_int size)
   2547 {
   2548 	if (size < WAPBL_BLKPOOL_MIN)
   2549 		size = WAPBL_BLKPOOL_MIN;
   2550 	KASSERT(wr->wr_blkhash == 0);
   2551 #ifdef _KERNEL
   2552 	wr->wr_blkhash = hashinit(size, HASH_LIST, true, &wr->wr_blkhashmask);
   2553 #else /* ! _KERNEL */
   2554 	/* Manually implement hashinit */
   2555 	{
   2556 		unsigned long i, hashsize;
   2557 		for (hashsize = 1; hashsize < size; hashsize <<= 1)
   2558 			continue;
   2559 		wr->wr_blkhash = wapbl_alloc(hashsize * sizeof(*wr->wr_blkhash));
   2560 		for (i = 0; i < hashsize; i++)
   2561 			LIST_INIT(&wr->wr_blkhash[i]);
   2562 		wr->wr_blkhashmask = hashsize - 1;
   2563 	}
   2564 #endif /* ! _KERNEL */
   2565 }
   2566 
   2567 static void
   2568 wapbl_blkhash_free(struct wapbl_replay *wr)
   2569 {
   2570 	KASSERT(wr->wr_blkhashcnt == 0);
   2571 #ifdef _KERNEL
   2572 	hashdone(wr->wr_blkhash, HASH_LIST, wr->wr_blkhashmask);
   2573 #else /* ! _KERNEL */
   2574 	wapbl_free(wr->wr_blkhash,
   2575 	    (wr->wr_blkhashmask + 1) * sizeof(*wr->wr_blkhash));
   2576 #endif /* ! _KERNEL */
   2577 }
   2578 
   2579 static struct wapbl_blk *
   2580 wapbl_blkhash_get(struct wapbl_replay *wr, daddr_t blk)
   2581 {
   2582 	struct wapbl_blk_head *wbh;
   2583 	struct wapbl_blk *wb;
   2584 	wbh = &wr->wr_blkhash[blk & wr->wr_blkhashmask];
   2585 	LIST_FOREACH(wb, wbh, wb_hash) {
   2586 		if (blk == wb->wb_blk)
   2587 			return wb;
   2588 	}
   2589 	return 0;
   2590 }
   2591 
   2592 static void
   2593 wapbl_blkhash_ins(struct wapbl_replay *wr, daddr_t blk, off_t off)
   2594 {
   2595 	struct wapbl_blk_head *wbh;
   2596 	struct wapbl_blk *wb;
   2597 	wb = wapbl_blkhash_get(wr, blk);
   2598 	if (wb) {
   2599 		KASSERT(wb->wb_blk == blk);
   2600 		wb->wb_off = off;
   2601 	} else {
   2602 		wb = wapbl_alloc(sizeof(*wb));
   2603 		wb->wb_blk = blk;
   2604 		wb->wb_off = off;
   2605 		wbh = &wr->wr_blkhash[blk & wr->wr_blkhashmask];
   2606 		LIST_INSERT_HEAD(wbh, wb, wb_hash);
   2607 		wr->wr_blkhashcnt++;
   2608 	}
   2609 }
   2610 
   2611 static void
   2612 wapbl_blkhash_rem(struct wapbl_replay *wr, daddr_t blk)
   2613 {
   2614 	struct wapbl_blk *wb = wapbl_blkhash_get(wr, blk);
   2615 	if (wb) {
   2616 		KASSERT(wr->wr_blkhashcnt > 0);
   2617 		wr->wr_blkhashcnt--;
   2618 		LIST_REMOVE(wb, wb_hash);
   2619 		wapbl_free(wb, sizeof(*wb));
   2620 	}
   2621 }
   2622 
   2623 static void
   2624 wapbl_blkhash_clear(struct wapbl_replay *wr)
   2625 {
   2626 	unsigned long i;
   2627 	for (i = 0; i <= wr->wr_blkhashmask; i++) {
   2628 		struct wapbl_blk *wb;
   2629 
   2630 		while ((wb = LIST_FIRST(&wr->wr_blkhash[i]))) {
   2631 			KASSERT(wr->wr_blkhashcnt > 0);
   2632 			wr->wr_blkhashcnt--;
   2633 			LIST_REMOVE(wb, wb_hash);
   2634 			wapbl_free(wb, sizeof(*wb));
   2635 		}
   2636 	}
   2637 	KASSERT(wr->wr_blkhashcnt == 0);
   2638 }
   2639 
   2640 /****************************************************************/
   2641 
   2642 /*
   2643  * wapbl_circ_read(wr, data, len, offp)
   2644  *
   2645  *	Read len bytes into data from the circular queue of wr,
   2646  *	starting at the linear byte offset *offp, and returning the new
   2647  *	linear byte offset in *offp.
   2648  *
   2649  *	If the starting linear byte offset precedes wr->wr_circ_off,
   2650  *	the read instead begins at wr->wr_circ_off.  XXX WTF?  This
   2651  *	should be a KASSERT, not a conditional.
   2652  */
   2653 static int
   2654 wapbl_circ_read(struct wapbl_replay *wr, void *data, size_t len, off_t *offp)
   2655 {
   2656 	size_t slen;
   2657 	off_t off = *offp;
   2658 	int error;
   2659 	daddr_t pbn;
   2660 
   2661 	KASSERT(((len >> wr->wr_log_dev_bshift) <<
   2662 	    wr->wr_log_dev_bshift) == len);
   2663 
   2664 	if (off < wr->wr_circ_off)
   2665 		off = wr->wr_circ_off;
   2666 	slen = wr->wr_circ_off + wr->wr_circ_size - off;
   2667 	if (slen < len) {
   2668 		pbn = wr->wr_logpbn + (off >> wr->wr_log_dev_bshift);
   2669 #ifdef _KERNEL
   2670 		pbn = btodb(pbn << wr->wr_log_dev_bshift);
   2671 #endif
   2672 		error = wapbl_read(data, slen, wr->wr_devvp, pbn);
   2673 		if (error)
   2674 			return error;
   2675 		data = (uint8_t *)data + slen;
   2676 		len -= slen;
   2677 		off = wr->wr_circ_off;
   2678 	}
   2679 	pbn = wr->wr_logpbn + (off >> wr->wr_log_dev_bshift);
   2680 #ifdef _KERNEL
   2681 	pbn = btodb(pbn << wr->wr_log_dev_bshift);
   2682 #endif
   2683 	error = wapbl_read(data, len, wr->wr_devvp, pbn);
   2684 	if (error)
   2685 		return error;
   2686 	off += len;
   2687 	if (off >= wr->wr_circ_off + wr->wr_circ_size)
   2688 		off = wr->wr_circ_off;
   2689 	*offp = off;
   2690 	return 0;
   2691 }
   2692 
   2693 /*
   2694  * wapbl_circ_advance(wr, len, offp)
   2695  *
   2696  *	Compute the linear byte offset of the circular queue of wr that
   2697  *	is len bytes past *offp, and store it in *offp.
   2698  *
   2699  *	This is as if wapbl_circ_read, but without actually reading
   2700  *	anything.
   2701  *
   2702  *	If the starting linear byte offset precedes wr->wr_circ_off, it
   2703  *	is taken to be wr->wr_circ_off instead.  XXX WTF?  This should
   2704  *	be a KASSERT, not a conditional.
   2705  */
   2706 static void
   2707 wapbl_circ_advance(struct wapbl_replay *wr, size_t len, off_t *offp)
   2708 {
   2709 	size_t slen;
   2710 	off_t off = *offp;
   2711 
   2712 	KASSERT(((len >> wr->wr_log_dev_bshift) <<
   2713 	    wr->wr_log_dev_bshift) == len);
   2714 
   2715 	if (off < wr->wr_circ_off)
   2716 		off = wr->wr_circ_off;
   2717 	slen = wr->wr_circ_off + wr->wr_circ_size - off;
   2718 	if (slen < len) {
   2719 		len -= slen;
   2720 		off = wr->wr_circ_off;
   2721 	}
   2722 	off += len;
   2723 	if (off >= wr->wr_circ_off + wr->wr_circ_size)
   2724 		off = wr->wr_circ_off;
   2725 	*offp = off;
   2726 }
   2727 
   2728 /****************************************************************/
   2729 
   2730 int
   2731 wapbl_replay_start(struct wapbl_replay **wrp, struct vnode *vp,
   2732 	daddr_t off, size_t count, size_t blksize)
   2733 {
   2734 	struct wapbl_replay *wr;
   2735 	int error;
   2736 	struct vnode *devvp;
   2737 	daddr_t logpbn;
   2738 	uint8_t *scratch;
   2739 	struct wapbl_wc_header *wch;
   2740 	struct wapbl_wc_header *wch2;
   2741 	/* Use this until we read the actual log header */
   2742 	int log_dev_bshift = ilog2(blksize);
   2743 	size_t used;
   2744 	daddr_t pbn;
   2745 
   2746 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY,
   2747 	    ("wapbl_replay_start: vp=%p off=%"PRId64 " count=%zu blksize=%zu\n",
   2748 	    vp, off, count, blksize));
   2749 
   2750 	if (off < 0)
   2751 		return EINVAL;
   2752 
   2753 	if (blksize < DEV_BSIZE)
   2754 		return EINVAL;
   2755 	if (blksize % DEV_BSIZE)
   2756 		return EINVAL;
   2757 
   2758 #ifdef _KERNEL
   2759 #if 0
   2760 	/* XXX vp->v_size isn't reliably set for VBLK devices,
   2761 	 * especially root.  However, we might still want to verify
   2762 	 * that the full load is readable */
   2763 	if ((off + count) * blksize > vp->v_size)
   2764 		return EINVAL;
   2765 #endif
   2766 	if ((error = VOP_BMAP(vp, off, &devvp, &logpbn, 0)) != 0) {
   2767 		return error;
   2768 	}
   2769 #else /* ! _KERNEL */
   2770 	devvp = vp;
   2771 	logpbn = off;
   2772 #endif /* ! _KERNEL */
   2773 
   2774 	scratch = wapbl_alloc(MAXBSIZE);
   2775 
   2776 	pbn = logpbn;
   2777 #ifdef _KERNEL
   2778 	pbn = btodb(pbn << log_dev_bshift);
   2779 #endif
   2780 	error = wapbl_read(scratch, 2<<log_dev_bshift, devvp, pbn);
   2781 	if (error)
   2782 		goto errout;
   2783 
   2784 	wch = (struct wapbl_wc_header *)scratch;
   2785 	wch2 =
   2786 	    (struct wapbl_wc_header *)(scratch + (1<<log_dev_bshift));
   2787 	/* XXX verify checksums and magic numbers */
   2788 	if (wch->wc_type != WAPBL_WC_HEADER) {
   2789 		printf("Unrecognized wapbl magic: 0x%08x\n", wch->wc_type);
   2790 		error = EFTYPE;
   2791 		goto errout;
   2792 	}
   2793 
   2794 	if (wch2->wc_generation > wch->wc_generation)
   2795 		wch = wch2;
   2796 
   2797 	wr = wapbl_calloc(1, sizeof(*wr));
   2798 
   2799 	wr->wr_logvp = vp;
   2800 	wr->wr_devvp = devvp;
   2801 	wr->wr_logpbn = logpbn;
   2802 
   2803 	wr->wr_scratch = scratch;
   2804 
   2805 	wr->wr_log_dev_bshift = wch->wc_log_dev_bshift;
   2806 	wr->wr_fs_dev_bshift = wch->wc_fs_dev_bshift;
   2807 	wr->wr_circ_off = wch->wc_circ_off;
   2808 	wr->wr_circ_size = wch->wc_circ_size;
   2809 	wr->wr_generation = wch->wc_generation;
   2810 
   2811 	used = wapbl_space_used(wch->wc_circ_size, wch->wc_head, wch->wc_tail);
   2812 
   2813 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY,
   2814 	    ("wapbl_replay: head=%"PRId64" tail=%"PRId64" off=%"PRId64
   2815 	    " len=%"PRId64" used=%zu\n",
   2816 	    wch->wc_head, wch->wc_tail, wch->wc_circ_off,
   2817 	    wch->wc_circ_size, used));
   2818 
   2819 	wapbl_blkhash_init(wr, (used >> wch->wc_fs_dev_bshift));
   2820 
   2821 	error = wapbl_replay_process(wr, wch->wc_head, wch->wc_tail);
   2822 	if (error) {
   2823 		wapbl_replay_stop(wr);
   2824 		wapbl_replay_free(wr);
   2825 		return error;
   2826 	}
   2827 
   2828 	*wrp = wr;
   2829 	return 0;
   2830 
   2831  errout:
   2832 	wapbl_free(scratch, MAXBSIZE);
   2833 	return error;
   2834 }
   2835 
   2836 void
   2837 wapbl_replay_stop(struct wapbl_replay *wr)
   2838 {
   2839 
   2840 	if (!wapbl_replay_isopen(wr))
   2841 		return;
   2842 
   2843 	WAPBL_PRINTF(WAPBL_PRINT_REPLAY, ("wapbl_replay_stop called\n"));
   2844 
   2845 	wapbl_free(wr->wr_scratch, MAXBSIZE);
   2846 	wr->wr_scratch = NULL;
   2847 
   2848 	wr->wr_logvp = NULL;
   2849 
   2850 	wapbl_blkhash_clear(wr);
   2851 	wapbl_blkhash_free(wr);
   2852 }
   2853 
   2854 void
   2855 wapbl_replay_free(struct wapbl_replay *wr)
   2856 {
   2857 
   2858 	KDASSERT(!wapbl_replay_isopen(wr));
   2859 
   2860 	if (wr->wr_inodes)
   2861 		wapbl_free(wr->wr_inodes,
   2862 		    wr->wr_inodescnt * sizeof(wr->wr_inodes[0]));
   2863 	wapbl_free(wr, sizeof(*wr));
   2864 }
   2865 
   2866 #ifdef _KERNEL
   2867 int
   2868 wapbl_replay_isopen1(struct wapbl_replay *wr)
   2869 {
   2870 
   2871 	return wapbl_replay_isopen(wr);
   2872 }
   2873 #endif
   2874 
   2875 /*
   2876  * calculate the disk address for the i'th block in the wc_blockblist
   2877  * offset by j blocks of size blen.
   2878  *
   2879  * wc_daddr is always a kernel disk address in DEV_BSIZE units that
   2880  * was written to the journal.
   2881  *
   2882  * The kernel needs that address plus the offset in DEV_BSIZE units.
   2883  *
   2884  * Userland needs that address plus the offset in blen units.
   2885  *
   2886  */
   2887 static daddr_t
   2888 wapbl_block_daddr(struct wapbl_wc_blocklist *wc, int i, int j, int blen)
   2889 {
   2890 	daddr_t pbn;
   2891 
   2892 #ifdef _KERNEL
   2893 	pbn = wc->wc_blocks[i].wc_daddr + btodb(j * blen);
   2894 #else
   2895 	pbn = dbtob(wc->wc_blocks[i].wc_daddr) / blen + j;
   2896 #endif
   2897 
   2898 	return pbn;
   2899 }
   2900 
   2901 static void
   2902 wapbl_replay_process_blocks(struct wapbl_replay *wr, off_t *offp)
   2903 {
   2904 	struct wapbl_wc_blocklist *wc =
   2905 	    (struct wapbl_wc_blocklist *)wr->wr_scratch;
   2906 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   2907 	int i, j, n;
   2908 
   2909 	for (i = 0; i < wc->wc_blkcount; i++) {
   2910 		/*
   2911 		 * Enter each physical block into the hashtable independently.
   2912 		 */
   2913 		n = wc->wc_blocks[i].wc_dlen >> wr->wr_fs_dev_bshift;
   2914 		for (j = 0; j < n; j++) {
   2915 			wapbl_blkhash_ins(wr, wapbl_block_daddr(wc, i, j, fsblklen),
   2916 			    *offp);
   2917 			wapbl_circ_advance(wr, fsblklen, offp);
   2918 		}
   2919 	}
   2920 }
   2921 
   2922 static void
   2923 wapbl_replay_process_revocations(struct wapbl_replay *wr)
   2924 {
   2925 	struct wapbl_wc_blocklist *wc =
   2926 	    (struct wapbl_wc_blocklist *)wr->wr_scratch;
   2927 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   2928 	int i, j, n;
   2929 
   2930 	for (i = 0; i < wc->wc_blkcount; i++) {
   2931 		/*
   2932 		 * Remove any blocks found from the hashtable.
   2933 		 */
   2934 		n = wc->wc_blocks[i].wc_dlen >> wr->wr_fs_dev_bshift;
   2935 		for (j = 0; j < n; j++)
   2936 			wapbl_blkhash_rem(wr, wapbl_block_daddr(wc, i, j, fsblklen));
   2937 	}
   2938 }
   2939 
   2940 static void
   2941 wapbl_replay_process_inodes(struct wapbl_replay *wr, off_t oldoff, off_t newoff)
   2942 {
   2943 	struct wapbl_wc_inodelist *wc =
   2944 	    (struct wapbl_wc_inodelist *)wr->wr_scratch;
   2945 	void *new_inodes;
   2946 	const size_t oldsize = wr->wr_inodescnt * sizeof(wr->wr_inodes[0]);
   2947 
   2948 	KASSERT(sizeof(wr->wr_inodes[0]) == sizeof(wc->wc_inodes[0]));
   2949 
   2950 	/*
   2951 	 * Keep track of where we found this so location won't be
   2952 	 * overwritten.
   2953 	 */
   2954 	if (wc->wc_clear) {
   2955 		wr->wr_inodestail = oldoff;
   2956 		wr->wr_inodescnt = 0;
   2957 		if (wr->wr_inodes != NULL) {
   2958 			wapbl_free(wr->wr_inodes, oldsize);
   2959 			wr->wr_inodes = NULL;
   2960 		}
   2961 	}
   2962 	wr->wr_inodeshead = newoff;
   2963 	if (wc->wc_inocnt == 0)
   2964 		return;
   2965 
   2966 	new_inodes = wapbl_alloc((wr->wr_inodescnt + wc->wc_inocnt) *
   2967 	    sizeof(wr->wr_inodes[0]));
   2968 	if (wr->wr_inodes != NULL) {
   2969 		memcpy(new_inodes, wr->wr_inodes, oldsize);
   2970 		wapbl_free(wr->wr_inodes, oldsize);
   2971 	}
   2972 	wr->wr_inodes = new_inodes;
   2973 	memcpy(&wr->wr_inodes[wr->wr_inodescnt], wc->wc_inodes,
   2974 	    wc->wc_inocnt * sizeof(wr->wr_inodes[0]));
   2975 	wr->wr_inodescnt += wc->wc_inocnt;
   2976 }
   2977 
   2978 static int
   2979 wapbl_replay_process(struct wapbl_replay *wr, off_t head, off_t tail)
   2980 {
   2981 	off_t off;
   2982 	int error;
   2983 
   2984 	int logblklen = 1 << wr->wr_log_dev_bshift;
   2985 
   2986 	wapbl_blkhash_clear(wr);
   2987 
   2988 	off = tail;
   2989 	while (off != head) {
   2990 		struct wapbl_wc_null *wcn;
   2991 		off_t saveoff = off;
   2992 		error = wapbl_circ_read(wr, wr->wr_scratch, logblklen, &off);
   2993 		if (error)
   2994 			goto errout;
   2995 		wcn = (struct wapbl_wc_null *)wr->wr_scratch;
   2996 		switch (wcn->wc_type) {
   2997 		case WAPBL_WC_BLOCKS:
   2998 			wapbl_replay_process_blocks(wr, &off);
   2999 			break;
   3000 
   3001 		case WAPBL_WC_REVOCATIONS:
   3002 			wapbl_replay_process_revocations(wr);
   3003 			break;
   3004 
   3005 		case WAPBL_WC_INODES:
   3006 			wapbl_replay_process_inodes(wr, saveoff, off);
   3007 			break;
   3008 
   3009 		default:
   3010 			printf("Unrecognized wapbl type: 0x%08x\n",
   3011 			       wcn->wc_type);
   3012  			error = EFTYPE;
   3013 			goto errout;
   3014 		}
   3015 		wapbl_circ_advance(wr, wcn->wc_len, &saveoff);
   3016 		if (off != saveoff) {
   3017 			printf("wapbl_replay: corrupted records\n");
   3018 			error = EFTYPE;
   3019 			goto errout;
   3020 		}
   3021 	}
   3022 	return 0;
   3023 
   3024  errout:
   3025 	wapbl_blkhash_clear(wr);
   3026 	return error;
   3027 }
   3028 
   3029 #if 0
   3030 int
   3031 wapbl_replay_verify(struct wapbl_replay *wr, struct vnode *fsdevvp)
   3032 {
   3033 	off_t off;
   3034 	int mismatchcnt = 0;
   3035 	int logblklen = 1 << wr->wr_log_dev_bshift;
   3036 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   3037 	void *scratch1 = wapbl_alloc(MAXBSIZE);
   3038 	void *scratch2 = wapbl_alloc(MAXBSIZE);
   3039 	int error = 0;
   3040 
   3041 	KDASSERT(wapbl_replay_isopen(wr));
   3042 
   3043 	off = wch->wc_tail;
   3044 	while (off != wch->wc_head) {
   3045 		struct wapbl_wc_null *wcn;
   3046 #ifdef DEBUG
   3047 		off_t saveoff = off;
   3048 #endif
   3049 		error = wapbl_circ_read(wr, wr->wr_scratch, logblklen, &off);
   3050 		if (error)
   3051 			goto out;
   3052 		wcn = (struct wapbl_wc_null *)wr->wr_scratch;
   3053 		switch (wcn->wc_type) {
   3054 		case WAPBL_WC_BLOCKS:
   3055 			{
   3056 				struct wapbl_wc_blocklist *wc =
   3057 				    (struct wapbl_wc_blocklist *)wr->wr_scratch;
   3058 				int i;
   3059 				for (i = 0; i < wc->wc_blkcount; i++) {
   3060 					int foundcnt = 0;
   3061 					int dirtycnt = 0;
   3062 					int j, n;
   3063 					/*
   3064 					 * Check each physical block into the
   3065 					 * hashtable independently
   3066 					 */
   3067 					n = wc->wc_blocks[i].wc_dlen >>
   3068 					    wch->wc_fs_dev_bshift;
   3069 					for (j = 0; j < n; j++) {
   3070 						struct wapbl_blk *wb =
   3071 						   wapbl_blkhash_get(wr,
   3072 						   wapbl_block_daddr(wc, i, j, fsblklen));
   3073 						if (wb && (wb->wb_off == off)) {
   3074 							foundcnt++;
   3075 							error =
   3076 							    wapbl_circ_read(wr,
   3077 							    scratch1, fsblklen,
   3078 							    &off);
   3079 							if (error)
   3080 								goto out;
   3081 							error =
   3082 							    wapbl_read(scratch2,
   3083 							    fsblklen, fsdevvp,
   3084 							    wb->wb_blk);
   3085 							if (error)
   3086 								goto out;
   3087 							if (memcmp(scratch1,
   3088 								   scratch2,
   3089 								   fsblklen)) {
   3090 								printf(
   3091 		"wapbl_verify: mismatch block %"PRId64" at off %"PRIdMAX"\n",
   3092 		wb->wb_blk, (intmax_t)off);
   3093 								dirtycnt++;
   3094 								mismatchcnt++;
   3095 							}
   3096 						} else {
   3097 							wapbl_circ_advance(wr,
   3098 							    fsblklen, &off);
   3099 						}
   3100 					}
   3101 #if 0
   3102 					/*
   3103 					 * If all of the blocks in an entry
   3104 					 * are clean, then remove all of its
   3105 					 * blocks from the hashtable since they
   3106 					 * never will need replay.
   3107 					 */
   3108 					if ((foundcnt != 0) &&
   3109 					    (dirtycnt == 0)) {
   3110 						off = saveoff;
   3111 						wapbl_circ_advance(wr,
   3112 						    logblklen, &off);
   3113 						for (j = 0; j < n; j++) {
   3114 							struct wapbl_blk *wb =
   3115 							   wapbl_blkhash_get(wr,
   3116 							   wapbl_block_daddr(wc, i, j, fsblklen));
   3117 							if (wb &&
   3118 							  (wb->wb_off == off)) {
   3119 								wapbl_blkhash_rem(wr, wb->wb_blk);
   3120 							}
   3121 							wapbl_circ_advance(wr,
   3122 							    fsblklen, &off);
   3123 						}
   3124 					}
   3125 #endif
   3126 				}
   3127 			}
   3128 			break;
   3129 		case WAPBL_WC_REVOCATIONS:
   3130 		case WAPBL_WC_INODES:
   3131 			break;
   3132 		default:
   3133 			KASSERT(0);
   3134 		}
   3135 #ifdef DEBUG
   3136 		wapbl_circ_advance(wr, wcn->wc_len, &saveoff);
   3137 		KASSERT(off == saveoff);
   3138 #endif
   3139 	}
   3140  out:
   3141 	wapbl_free(scratch1, MAXBSIZE);
   3142 	wapbl_free(scratch2, MAXBSIZE);
   3143 	if (!error && mismatchcnt)
   3144 		error = EFTYPE;
   3145 	return error;
   3146 }
   3147 #endif
   3148 
   3149 int
   3150 wapbl_replay_write(struct wapbl_replay *wr, struct vnode *fsdevvp)
   3151 {
   3152 	struct wapbl_blk *wb;
   3153 	size_t i;
   3154 	off_t off;
   3155 	void *scratch;
   3156 	int error = 0;
   3157 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   3158 
   3159 	KDASSERT(wapbl_replay_isopen(wr));
   3160 
   3161 	scratch = wapbl_alloc(MAXBSIZE);
   3162 
   3163 	for (i = 0; i <= wr->wr_blkhashmask; ++i) {
   3164 		LIST_FOREACH(wb, &wr->wr_blkhash[i], wb_hash) {
   3165 			off = wb->wb_off;
   3166 			error = wapbl_circ_read(wr, scratch, fsblklen, &off);
   3167 			if (error)
   3168 				break;
   3169 			error = wapbl_write(scratch, fsblklen, fsdevvp,
   3170 			    wb->wb_blk);
   3171 			if (error)
   3172 				break;
   3173 		}
   3174 	}
   3175 
   3176 	wapbl_free(scratch, MAXBSIZE);
   3177 	return error;
   3178 }
   3179 
   3180 int
   3181 wapbl_replay_can_read(struct wapbl_replay *wr, daddr_t blk, long len)
   3182 {
   3183 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   3184 
   3185 	KDASSERT(wapbl_replay_isopen(wr));
   3186 	KASSERT((len % fsblklen) == 0);
   3187 
   3188 	while (len != 0) {
   3189 		struct wapbl_blk *wb = wapbl_blkhash_get(wr, blk);
   3190 		if (wb)
   3191 			return 1;
   3192 		len -= fsblklen;
   3193 	}
   3194 	return 0;
   3195 }
   3196 
   3197 int
   3198 wapbl_replay_read(struct wapbl_replay *wr, void *data, daddr_t blk, long len)
   3199 {
   3200 	int fsblklen = 1 << wr->wr_fs_dev_bshift;
   3201 
   3202 	KDASSERT(wapbl_replay_isopen(wr));
   3203 
   3204 	KASSERT((len % fsblklen) == 0);
   3205 
   3206 	while (len != 0) {
   3207 		struct wapbl_blk *wb = wapbl_blkhash_get(wr, blk);
   3208 		if (wb) {
   3209 			off_t off = wb->wb_off;
   3210 			int error;
   3211 			error = wapbl_circ_read(wr, data, fsblklen, &off);
   3212 			if (error)
   3213 				return error;
   3214 		}
   3215 		data = (uint8_t *)data + fsblklen;
   3216 		len -= fsblklen;
   3217 		blk++;
   3218 	}
   3219 	return 0;
   3220 }
   3221 
   3222 #ifdef _KERNEL
   3223 
   3224 MODULE(MODULE_CLASS_VFS, wapbl, NULL);
   3225 
   3226 static int
   3227 wapbl_modcmd(modcmd_t cmd, void *arg)
   3228 {
   3229 
   3230 	switch (cmd) {
   3231 	case MODULE_CMD_INIT:
   3232 		wapbl_init();
   3233 		return 0;
   3234 	case MODULE_CMD_FINI:
   3235 		return wapbl_fini();
   3236 	default:
   3237 		return ENOTTY;
   3238 	}
   3239 }
   3240 #endif /* _KERNEL */
   3241