1 /*
2  * Copyright (c) 2011-2015 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@dragonflybsd.org>
6  * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
7  * by Daniel Flores (GSOC 2013 - mentored by Matthew Dillon, compression)
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
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
17  *    the documentation and/or other materials provided with the
18  *    distribution.
19  * 3. Neither the name of The DragonFly Project nor the names of its
20  *    contributors may be used to endorse or promote products derived
21  *    from this software without specific, prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
26  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
27  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
28  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
29  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
31  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
32  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
33  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 /*
37  * This module handles low level logical file I/O (strategy) which backs
38  * the logical buffer cache.
39  *
40  * [De]compression, zero-block, check codes, and buffer cache operations
41  * for file data is handled here.
42  *
43  * Live dedup makes its home here as well.
44  */
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
49 #include <sys/fcntl.h>
50 #include <sys/buf.h>
51 #include <sys/proc.h>
52 #include <sys/namei.h>
53 #include <sys/mount.h>
54 #include <sys/vnode.h>
55 #include <sys/mountctl.h>
56 #include <sys/dirent.h>
57 #include <sys/uio.h>
58 #include <sys/objcache.h>
59 #include <sys/event.h>
60 #include <sys/file.h>
61 #include <vfs/fifofs/fifo.h>
62 
63 #include "hammer2.h"
64 #include "hammer2_lz4.h"
65 
66 #include "zlib/hammer2_zlib.h"
67 
68 struct objcache *cache_buffer_read;
69 struct objcache *cache_buffer_write;
70 
71 /*
72  * Strategy code (async logical file buffer I/O from system)
73  *
74  * Except for the transaction init (which should normally not block),
75  * we essentially run the strategy operation asynchronously via a XOP.
76  *
77  * XXX This isn't supposed to be able to deadlock against vfs_sync vfsync()
78  *     calls but it has in the past when multiple flushes are queued.
79  *
80  * XXX We currently terminate the transaction once we get a quorum, otherwise
81  *     the frontend can stall, but this can leave the remaining nodes with
82  *     a potential flush conflict.  We need to delay flushes on those nodes
83  *     until running transactions complete separately from the normal
84  *     transaction sequencing.  FIXME TODO.
85  */
86 static void hammer2_strategy_xop_read(hammer2_xop_t *arg, int clindex);
87 static void hammer2_strategy_xop_write(hammer2_xop_t *arg, int clindex);
88 static int hammer2_strategy_read(struct vop_strategy_args *ap);
89 static int hammer2_strategy_write(struct vop_strategy_args *ap);
90 static void hammer2_strategy_read_completion(hammer2_chain_t *chain,
91 				char *data, struct bio *bio);
92 
93 static hammer2_off_t hammer2_dedup_lookup(hammer2_dev_t *hmp,
94 			char **datap, int pblksize);
95 
96 int h2timer[32];
97 int h2last;
98 int h2lid;
99 
100 #define TIMER(which)	do {				\
101 	if (h2last) 					\
102 		h2timer[h2lid] += (int)(ticks - h2last);\
103 	h2last = ticks;					\
104 	h2lid = which;					\
105 } while(0)
106 
107 int
108 hammer2_vop_strategy(struct vop_strategy_args *ap)
109 {
110 	struct bio *biop;
111 	struct buf *bp;
112 	int error;
113 
114 	biop = ap->a_bio;
115 	bp = biop->bio_buf;
116 
117 	switch(bp->b_cmd) {
118 	case BUF_CMD_READ:
119 		error = hammer2_strategy_read(ap);
120 		++hammer2_iod_file_read;
121 		break;
122 	case BUF_CMD_WRITE:
123 		error = hammer2_strategy_write(ap);
124 		++hammer2_iod_file_write;
125 		break;
126 	default:
127 		bp->b_error = error = EINVAL;
128 		bp->b_flags |= B_ERROR;
129 		biodone(biop);
130 		break;
131 	}
132 	return (error);
133 }
134 
135 /*
136  * Return the largest contiguous physical disk range for the logical
137  * request, in bytes.
138  *
139  * (struct vnode *vp, off_t loffset, off_t *doffsetp, int *runp, int *runb)
140  *
141  * Basically disabled, the logical buffer write thread has to deal with
142  * buffers one-at-a-time.  Note that this should not prevent cluster_read()
143  * from reading-ahead, it simply prevents it from trying form a single
144  * cluster buffer for the logical request.  H2 already uses 64KB buffers!
145  */
146 int
147 hammer2_vop_bmap(struct vop_bmap_args *ap)
148 {
149 	*ap->a_doffsetp = NOOFFSET;
150 	if (ap->a_runp)
151 		*ap->a_runp = 0;
152 	if (ap->a_runb)
153 		*ap->a_runb = 0;
154 	return (EOPNOTSUPP);
155 }
156 
157 /****************************************************************************
158  *				READ SUPPORT				    *
159  ****************************************************************************/
160 /*
161  * Callback used in read path in case that a block is compressed with LZ4.
162  */
163 static
164 void
165 hammer2_decompress_LZ4_callback(const char *data, u_int bytes, struct bio *bio)
166 {
167 	struct buf *bp;
168 	char *compressed_buffer;
169 	int compressed_size;
170 	int result;
171 
172 	bp = bio->bio_buf;
173 
174 #if 0
175 	if bio->bio_caller_info2.index &&
176 	      bio->bio_caller_info1.uvalue32 !=
177 	      crc32(bp->b_data, bp->b_bufsize) --- return error
178 #endif
179 
180 	KKASSERT(bp->b_bufsize <= HAMMER2_PBUFSIZE);
181 	compressed_size = *(const int *)data;
182 	KKASSERT((uint32_t)compressed_size <= bytes - sizeof(int));
183 
184 	compressed_buffer = objcache_get(cache_buffer_read, M_INTWAIT);
185 	result = LZ4_decompress_safe(__DECONST(char *, &data[sizeof(int)]),
186 				     compressed_buffer,
187 				     compressed_size,
188 				     bp->b_bufsize);
189 	if (result < 0) {
190 		kprintf("READ PATH: Error during decompression."
191 			"bio %016jx/%d\n",
192 			(intmax_t)bio->bio_offset, bytes);
193 		/* make sure it isn't random garbage */
194 		bzero(compressed_buffer, bp->b_bufsize);
195 	}
196 	KKASSERT(result <= bp->b_bufsize);
197 	bcopy(compressed_buffer, bp->b_data, bp->b_bufsize);
198 	if (result < bp->b_bufsize)
199 		bzero(bp->b_data + result, bp->b_bufsize - result);
200 	objcache_put(cache_buffer_read, compressed_buffer);
201 	bp->b_resid = 0;
202 	bp->b_flags |= B_AGE;
203 }
204 
205 /*
206  * Callback used in read path in case that a block is compressed with ZLIB.
207  * It is almost identical to LZ4 callback, so in theory they can be unified,
208  * but we didn't want to make changes in bio structure for that.
209  */
210 static
211 void
212 hammer2_decompress_ZLIB_callback(const char *data, u_int bytes, struct bio *bio)
213 {
214 	struct buf *bp;
215 	char *compressed_buffer;
216 	z_stream strm_decompress;
217 	int result;
218 	int ret;
219 
220 	bp = bio->bio_buf;
221 
222 	KKASSERT(bp->b_bufsize <= HAMMER2_PBUFSIZE);
223 	strm_decompress.avail_in = 0;
224 	strm_decompress.next_in = Z_NULL;
225 
226 	ret = inflateInit(&strm_decompress);
227 
228 	if (ret != Z_OK)
229 		kprintf("HAMMER2 ZLIB: Fatal error in inflateInit.\n");
230 
231 	compressed_buffer = objcache_get(cache_buffer_read, M_INTWAIT);
232 	strm_decompress.next_in = __DECONST(char *, data);
233 
234 	/* XXX supply proper size, subset of device bp */
235 	strm_decompress.avail_in = bytes;
236 	strm_decompress.next_out = compressed_buffer;
237 	strm_decompress.avail_out = bp->b_bufsize;
238 
239 	ret = inflate(&strm_decompress, Z_FINISH);
240 	if (ret != Z_STREAM_END) {
241 		kprintf("HAMMER2 ZLIB: Fatar error during decompression.\n");
242 		bzero(compressed_buffer, bp->b_bufsize);
243 	}
244 	bcopy(compressed_buffer, bp->b_data, bp->b_bufsize);
245 	result = bp->b_bufsize - strm_decompress.avail_out;
246 	if (result < bp->b_bufsize)
247 		bzero(bp->b_data + result, strm_decompress.avail_out);
248 	objcache_put(cache_buffer_read, compressed_buffer);
249 	ret = inflateEnd(&strm_decompress);
250 
251 	bp->b_resid = 0;
252 	bp->b_flags |= B_AGE;
253 }
254 
255 /*
256  * Logical buffer I/O, async read.
257  */
258 static
259 int
260 hammer2_strategy_read(struct vop_strategy_args *ap)
261 {
262 	hammer2_xop_strategy_t *xop;
263 	struct buf *bp;
264 	struct bio *bio;
265 	struct bio *nbio;
266 	hammer2_inode_t *ip;
267 	hammer2_key_t lbase;
268 
269 	bio = ap->a_bio;
270 	bp = bio->bio_buf;
271 	ip = VTOI(ap->a_vp);
272 	nbio = push_bio(bio);
273 
274 	lbase = bio->bio_offset;
275 	KKASSERT(((int)lbase & HAMMER2_PBUFMASK) == 0);
276 
277 	xop = hammer2_xop_alloc(ip, HAMMER2_XOP_STRATEGY);
278 	xop->finished = 0;
279 	xop->bio = bio;
280 	xop->lbase = lbase;
281 	hammer2_mtx_init(&xop->lock, "h2bior");
282 	hammer2_xop_start(&xop->head, hammer2_strategy_xop_read);
283 	/* asynchronous completion */
284 
285 	return(0);
286 }
287 
288 /*
289  * Per-node XOP (threaded), do a synchronous lookup of the chain and
290  * its data.  The frontend is asynchronous, so we are also responsible
291  * for racing to terminate the frontend.
292  */
293 static
294 void
295 hammer2_strategy_xop_read(hammer2_xop_t *arg, int clindex)
296 {
297 	hammer2_xop_strategy_t *xop = &arg->xop_strategy;
298 	hammer2_chain_t *parent;
299 	hammer2_chain_t *chain;
300 	hammer2_key_t key_dummy;
301 	hammer2_key_t lbase;
302 	struct bio *bio;
303 	struct buf *bp;
304 	int cache_index = -1;
305 	int error;
306 
307 	TIMER(0);
308 	lbase = xop->lbase;
309 	bio = xop->bio;
310 	bp = bio->bio_buf;
311 
312 	/*
313 	 * This is difficult to optimize.  The logical buffer might be
314 	 * partially dirty (contain dummy zero-fill pages), which would
315 	 * mess up our crc calculation if we were to try a direct read.
316 	 * So for now we always double-buffer through the underlying
317 	 * storage.
318 	 *
319 	 * If not for the above problem we could conditionalize on
320 	 * (1) 64KB buffer, (2) one chain (not multi-master) and
321 	 * (3) !hammer2_double_buffer, and issue a direct read into the
322 	 * logical buffer.
323 	 */
324 	parent = hammer2_inode_chain(xop->head.ip1, clindex,
325 				     HAMMER2_RESOLVE_ALWAYS |
326 				     HAMMER2_RESOLVE_SHARED);
327 	TIMER(1);
328 	if (parent) {
329 		chain = hammer2_chain_lookup(&parent, &key_dummy,
330 					     lbase, lbase,
331 					     &cache_index,
332 					     HAMMER2_LOOKUP_ALWAYS |
333 					     HAMMER2_LOOKUP_SHARED);
334 		error = chain ? chain->error : 0;
335 	} else {
336 		error = EIO;
337 		chain = NULL;
338 	}
339 	TIMER(2);
340 	error = hammer2_xop_feed(&xop->head, chain, clindex, error);
341 	TIMER(3);
342 	if (chain) {
343 		hammer2_chain_unlock(chain);
344 		hammer2_chain_drop(chain);
345 	}
346 	if (parent) {
347 		hammer2_chain_unlock(parent);
348 		hammer2_chain_drop(parent);
349 	}
350 	chain = NULL;	/* safety */
351 	parent = NULL;	/* safety */
352 	TIMER(4);
353 
354 	/*
355 	 * Race to finish the frontend
356 	 */
357 	if (xop->finished)
358 		return;
359 	hammer2_mtx_ex(&xop->lock);
360 	if (xop->finished) {
361 		hammer2_mtx_unlock(&xop->lock);
362 		return;
363 	}
364 
365 	/*
366 	 * Async operation has not completed and we now own the lock.
367 	 * Determine if we can complete the operation by issuing the
368 	 * frontend collection non-blocking.
369 	 *
370 	 * H2 double-buffers the data, setting B_NOTMETA on the logical
371 	 * buffer hints to the OS that the logical buffer should not be
372 	 * swapcached (since the device buffer can be).
373 	 *
374 	 * Also note that even for compressed data we would rather the
375 	 * kernel cache/swapcache device buffers more and (decompressed)
376 	 * logical buffers less, since that will significantly improve
377 	 * the amount of end-user data that can be cached.
378 	 */
379 	error = hammer2_xop_collect(&xop->head, HAMMER2_XOP_COLLECT_NOWAIT);
380 	TIMER(5);
381 
382 	switch(error) {
383 	case 0:
384 		xop->finished = 1;
385 		hammer2_mtx_unlock(&xop->lock);
386 		bp->b_flags |= B_NOTMETA;
387 		chain = xop->head.cluster.focus;
388 		hammer2_strategy_read_completion(chain, (char *)chain->data,
389 						 xop->bio);
390 		biodone(bio);
391 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
392 		break;
393 	case ENOENT:
394 		xop->finished = 1;
395 		hammer2_mtx_unlock(&xop->lock);
396 		bp->b_flags |= B_NOTMETA;
397 		bp->b_resid = 0;
398 		bp->b_error = 0;
399 		bzero(bp->b_data, bp->b_bcount);
400 		biodone(bio);
401 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
402 		break;
403 	case EINPROGRESS:
404 		hammer2_mtx_unlock(&xop->lock);
405 		break;
406 	default:
407 		kprintf("strategy_xop_read: error %d loff=%016jx\n",
408 			error, bp->b_loffset);
409 		xop->finished = 1;
410 		hammer2_mtx_unlock(&xop->lock);
411 		bp->b_flags |= B_ERROR;
412 		bp->b_error = EIO;
413 		biodone(bio);
414 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
415 		break;
416 	}
417 	TIMER(6);
418 }
419 
420 static
421 void
422 hammer2_strategy_read_completion(hammer2_chain_t *chain, char *data,
423 				 struct bio *bio)
424 {
425 	struct buf *bp = bio->bio_buf;
426 
427 	if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
428 		/*
429 		 * Data is embedded in the inode (copy from inode).
430 		 */
431 		bcopy(((hammer2_inode_data_t *)data)->u.data,
432 		      bp->b_data, HAMMER2_EMBEDDED_BYTES);
433 		bzero(bp->b_data + HAMMER2_EMBEDDED_BYTES,
434 		      bp->b_bcount - HAMMER2_EMBEDDED_BYTES);
435 		bp->b_resid = 0;
436 		bp->b_error = 0;
437 	} else if (chain->bref.type == HAMMER2_BREF_TYPE_DATA) {
438 		/*
439 		 * Data is on-media, record for live dedup.  Release the
440 		 * chain (try to free it) when done.  The data is still
441 		 * cached by both the buffer cache in front and the
442 		 * block device behind us.  This leaves more room in the
443 		 * LRU chain cache for meta-data chains which we really
444 		 * want to retain.
445 		 */
446 		hammer2_dedup_record(chain, data);
447 		atomic_set_int(&chain->flags, HAMMER2_CHAIN_RELEASE);
448 
449 		/*
450 		 * Decompression and copy.
451 		 */
452 		switch (HAMMER2_DEC_COMP(chain->bref.methods)) {
453 		case HAMMER2_COMP_LZ4:
454 			hammer2_decompress_LZ4_callback(data, chain->bytes,
455 							bio);
456 			/* b_resid set by call */
457 			break;
458 		case HAMMER2_COMP_ZLIB:
459 			hammer2_decompress_ZLIB_callback(data, chain->bytes,
460 							 bio);
461 			/* b_resid set by call */
462 			break;
463 		case HAMMER2_COMP_NONE:
464 			KKASSERT(chain->bytes <= bp->b_bcount);
465 			bcopy(data, bp->b_data, chain->bytes);
466 			if (chain->bytes < bp->b_bcount) {
467 				bzero(bp->b_data + chain->bytes,
468 				      bp->b_bcount - chain->bytes);
469 			}
470 			bp->b_resid = 0;
471 			bp->b_error = 0;
472 			break;
473 		default:
474 			panic("hammer2_strategy_read: "
475 			      "unknown compression type");
476 		}
477 	} else {
478 		panic("hammer2_strategy_read: unknown bref type");
479 	}
480 }
481 
482 /****************************************************************************
483  *				WRITE SUPPORT				    *
484  ****************************************************************************/
485 
486 /*
487  * Functions for compression in threads,
488  * from hammer2_vnops.c
489  */
490 static void hammer2_write_file_core(struct buf *bp, hammer2_inode_t *ip,
491 				hammer2_chain_t **parentp,
492 				hammer2_key_t lbase, int ioflag, int pblksize,
493 				hammer2_tid_t mtid, int *errorp);
494 static void hammer2_compress_and_write(struct buf *bp, hammer2_inode_t *ip,
495 				hammer2_chain_t **parentp,
496 				hammer2_key_t lbase, int ioflag, int pblksize,
497 				hammer2_tid_t mtid, int *errorp,
498 				int comp_algo, int check_algo);
499 static void hammer2_zero_check_and_write(struct buf *bp, hammer2_inode_t *ip,
500 				hammer2_chain_t **parentp,
501 				hammer2_key_t lbase, int ioflag, int pblksize,
502 				hammer2_tid_t mtid, int *errorp,
503 				int check_algo);
504 static int test_block_zeros(const char *buf, size_t bytes);
505 static void zero_write(struct buf *bp, hammer2_inode_t *ip,
506 				hammer2_chain_t **parentp,
507 				hammer2_key_t lbase,
508 				hammer2_tid_t mtid, int *errorp);
509 static void hammer2_write_bp(hammer2_chain_t *chain, struct buf *bp,
510 				int ioflag, int pblksize,
511 				hammer2_tid_t mtid, int *errorp,
512 				int check_algo);
513 
514 static
515 int
516 hammer2_strategy_write(struct vop_strategy_args *ap)
517 {
518 	hammer2_xop_strategy_t *xop;
519 	hammer2_pfs_t *pmp;
520 	struct bio *bio;
521 	struct buf *bp;
522 	hammer2_inode_t *ip;
523 
524 	bio = ap->a_bio;
525 	bp = bio->bio_buf;
526 	ip = VTOI(ap->a_vp);
527 	pmp = ip->pmp;
528 
529 	hammer2_lwinprog_ref(pmp);
530 	hammer2_trans_assert_strategy(pmp);
531 	hammer2_trans_init(pmp, HAMMER2_TRANS_BUFCACHE);
532 
533 	xop = hammer2_xop_alloc(ip, HAMMER2_XOP_MODIFYING |
534 				    HAMMER2_XOP_STRATEGY);
535 	xop->finished = 0;
536 	xop->bio = bio;
537 	xop->lbase = bio->bio_offset;
538 	hammer2_mtx_init(&xop->lock, "h2biow");
539 	hammer2_xop_start(&xop->head, hammer2_strategy_xop_write);
540 	/* asynchronous completion */
541 
542 	hammer2_lwinprog_wait(pmp, hammer2_flush_pipe);
543 
544 	return(0);
545 }
546 
547 /*
548  * Per-node XOP (threaded).  Write the logical buffer to the media.
549  */
550 static
551 void
552 hammer2_strategy_xop_write(hammer2_xop_t *arg, int clindex)
553 {
554 	hammer2_xop_strategy_t *xop = &arg->xop_strategy;
555 	hammer2_chain_t *parent;
556 	hammer2_key_t lbase;
557 	hammer2_inode_t *ip;
558 	struct bio *bio;
559 	struct buf *bp;
560 	int error;
561 	int lblksize;
562 	int pblksize;
563 
564 	lbase = xop->lbase;
565 	bio = xop->bio;
566 	bp = bio->bio_buf;
567 	ip = xop->head.ip1;
568 
569 	/* hammer2_trans_init(parent->hmp->spmp, HAMMER2_TRANS_BUFCACHE); */
570 
571 	lblksize = hammer2_calc_logical(ip, bio->bio_offset, &lbase, NULL);
572 	pblksize = hammer2_calc_physical(ip, lbase);
573 	parent = hammer2_inode_chain(ip, clindex, HAMMER2_RESOLVE_ALWAYS);
574 	hammer2_write_file_core(bp, ip, &parent,
575 				lbase, IO_ASYNC, pblksize,
576 				xop->head.mtid, &error);
577 	if (parent) {
578 		hammer2_chain_unlock(parent);
579 		hammer2_chain_drop(parent);
580 		parent = NULL;	/* safety */
581 	}
582 	hammer2_xop_feed(&xop->head, NULL, clindex, error);
583 
584 	/*
585 	 * Race to finish the frontend
586 	 */
587 	if (xop->finished)
588 		return;
589 	hammer2_mtx_ex(&xop->lock);
590 	if (xop->finished) {
591 		hammer2_mtx_unlock(&xop->lock);
592 		return;
593 	}
594 
595 	/*
596 	 * Async operation has not completed and we now own the lock.
597 	 * Determine if we can complete the operation by issuing the
598 	 * frontend collection non-blocking.
599 	 *
600 	 * H2 double-buffers the data, setting B_NOTMETA on the logical
601 	 * buffer hints to the OS that the logical buffer should not be
602 	 * swapcached (since the device buffer can be).
603 	 */
604 	error = hammer2_xop_collect(&xop->head, HAMMER2_XOP_COLLECT_NOWAIT);
605 
606 	if (error == EINPROGRESS) {
607 		hammer2_mtx_unlock(&xop->lock);
608 		return;
609 	}
610 
611 	/*
612 	 * Async operation has completed.
613 	 */
614 	xop->finished = 1;
615 	hammer2_mtx_unlock(&xop->lock);
616 
617 	if (error == ENOENT || error == 0) {
618 		bp->b_flags |= B_NOTMETA;
619 		bp->b_resid = 0;
620 		bp->b_error = 0;
621 		biodone(bio);
622 	} else {
623 		kprintf("strategy_xop_write: error %d loff=%016jx\n",
624 			error, bp->b_loffset);
625 		bp->b_flags |= B_ERROR;
626 		bp->b_error = EIO;
627 		biodone(bio);
628 	}
629 	hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
630 	hammer2_trans_assert_strategy(ip->pmp);
631 	hammer2_lwinprog_drop(ip->pmp);
632 	hammer2_trans_done(ip->pmp);
633 }
634 
635 /*
636  * Wait for pending I/O to complete
637  */
638 void
639 hammer2_bioq_sync(hammer2_pfs_t *pmp)
640 {
641 	hammer2_lwinprog_wait(pmp, 0);
642 }
643 
644 /*
645  * Create a new cluster at (cparent, lbase) and assign physical storage,
646  * returning a cluster suitable for I/O.  The cluster will be in a modified
647  * state.
648  *
649  * cparent can wind up being anything.
650  *
651  * If datap is not NULL, *datap points to the real data we intend to write.
652  * If we can dedup the storage location we set *datap to NULL to indicate
653  * to the caller that a dedup occurred.
654  *
655  * NOTE: Special case for data embedded in inode.
656  */
657 static
658 hammer2_chain_t *
659 hammer2_assign_physical(hammer2_inode_t *ip, hammer2_chain_t **parentp,
660 			hammer2_key_t lbase, int pblksize,
661 			hammer2_tid_t mtid, char **datap, int *errorp)
662 {
663 	hammer2_chain_t *chain;
664 	hammer2_key_t key_dummy;
665 	hammer2_off_t dedup_off;
666 	int pradix = hammer2_getradix(pblksize);
667 	int cache_index = -1;
668 
669 	/*
670 	 * Locate the chain associated with lbase, return a locked chain.
671 	 * However, do not instantiate any data reference (which utilizes a
672 	 * device buffer) because we will be using direct IO via the
673 	 * logical buffer cache buffer.
674 	 */
675 	*errorp = 0;
676 	KKASSERT(pblksize >= HAMMER2_ALLOC_MIN);
677 retry:
678 	TIMER(30);
679 	chain = hammer2_chain_lookup(parentp, &key_dummy,
680 				     lbase, lbase,
681 				     &cache_index,
682 				     HAMMER2_LOOKUP_NODATA);
683 
684 	/*
685 	 * The lookup code should not return a DELETED chain to us, unless
686 	 * its a short-file embedded in the inode.  Then it is possible for
687 	 * the lookup to return a deleted inode.
688 	 */
689 	if (chain && (chain->flags & HAMMER2_CHAIN_DELETED) &&
690 	    chain->bref.type != HAMMER2_BREF_TYPE_INODE) {
691 		kprintf("assign physical deleted chain @ "
692 			"%016jx (%016jx.%02x) ip %016jx\n",
693 			lbase, chain->bref.data_off, chain->bref.type,
694 			ip->meta.inum);
695 		Debugger("bleh");
696 	}
697 
698 	if (chain == NULL) {
699 		/*
700 		 * We found a hole, create a new chain entry.
701 		 *
702 		 * NOTE: DATA chains are created without device backing
703 		 *	 store (nor do we want any).
704 		 */
705 		dedup_off = hammer2_dedup_lookup((*parentp)->hmp, datap,
706 						 pblksize);
707 		*errorp = hammer2_chain_create(parentp, &chain,
708 					       ip->pmp,
709 				       HAMMER2_ENC_CHECK(ip->meta.check_algo) |
710 				       HAMMER2_ENC_COMP(HAMMER2_COMP_NONE),
711 					       lbase, HAMMER2_PBUFRADIX,
712 					       HAMMER2_BREF_TYPE_DATA,
713 					       pblksize, mtid,
714 					       dedup_off, 0);
715 		if (chain == NULL) {
716 			panic("hammer2_chain_create: par=%p error=%d\n",
717 			      *parentp, *errorp);
718 			goto retry;
719 		}
720 		/*ip->delta_dcount += pblksize;*/
721 	} else {
722 		switch (chain->bref.type) {
723 		case HAMMER2_BREF_TYPE_INODE:
724 			/*
725 			 * The data is embedded in the inode, which requires
726 			 * a bit more finess.
727 			 */
728 			hammer2_chain_modify_ip(ip, chain, mtid, 0);
729 			break;
730 		case HAMMER2_BREF_TYPE_DATA:
731 			dedup_off = hammer2_dedup_lookup(chain->hmp, datap,
732 							 pblksize);
733 			if (chain->bytes != pblksize) {
734 				hammer2_chain_resize(ip, *parentp, chain,
735 						     mtid, dedup_off,
736 						     pradix,
737 						     HAMMER2_MODIFY_OPTDATA);
738 			}
739 
740 			/*
741 			 * DATA buffers must be marked modified whether the
742 			 * data is in a logical buffer or not.  We also have
743 			 * to make this call to fixup the chain data pointers
744 			 * after resizing in case this is an encrypted or
745 			 * compressed buffer.
746 			 */
747 			hammer2_chain_modify(chain, mtid, dedup_off,
748 					     HAMMER2_MODIFY_OPTDATA);
749 			break;
750 		default:
751 			panic("hammer2_assign_physical: bad type");
752 			/* NOT REACHED */
753 			break;
754 		}
755 	}
756 	TIMER(31);
757 	return (chain);
758 }
759 
760 /*
761  * hammer2_write_file_core() - hammer2_write_thread() helper
762  *
763  * The core write function which determines which path to take
764  * depending on compression settings.  We also have to locate the
765  * related chains so we can calculate and set the check data for
766  * the blockref.
767  */
768 static
769 void
770 hammer2_write_file_core(struct buf *bp, hammer2_inode_t *ip,
771 			hammer2_chain_t **parentp,
772 			hammer2_key_t lbase, int ioflag, int pblksize,
773 			hammer2_tid_t mtid, int *errorp)
774 {
775 	hammer2_chain_t *chain;
776 	char *data = bp->b_data;
777 
778 	*errorp = 0;
779 
780 	switch(HAMMER2_DEC_ALGO(ip->meta.comp_algo)) {
781 	case HAMMER2_COMP_NONE:
782 		/*
783 		 * We have to assign physical storage to the buffer
784 		 * we intend to dirty or write now to avoid deadlocks
785 		 * in the strategy code later.
786 		 *
787 		 * This can return NOOFFSET for inode-embedded data.
788 		 * The strategy code will take care of it in that case.
789 		 */
790 		chain = hammer2_assign_physical(ip, parentp, lbase, pblksize,
791 						mtid, &data, errorp);
792 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
793 			hammer2_inode_data_t *wipdata;
794 
795 			wipdata = &chain->data->ipdata;
796 			KKASSERT(wipdata->meta.op_flags &
797 				 HAMMER2_OPFLAG_DIRECTDATA);
798 			KKASSERT(bp->b_loffset == 0);
799 			bcopy(bp->b_data, wipdata->u.data,
800 			      HAMMER2_EMBEDDED_BYTES);
801 			++hammer2_iod_file_wembed;
802 		} else if (data == NULL) {
803 			/*
804 			 * Copy of data already present on-media.
805 			 */
806 			chain->bref.methods =
807 				HAMMER2_ENC_COMP(HAMMER2_COMP_NONE) +
808 				HAMMER2_ENC_CHECK(ip->meta.check_algo);
809 			hammer2_chain_setcheck(chain, bp->b_data);
810 		} else {
811 			hammer2_write_bp(chain, bp, ioflag, pblksize,
812 					 mtid, errorp, ip->meta.check_algo);
813 		}
814 		if (chain) {
815 			hammer2_chain_unlock(chain);
816 			hammer2_chain_drop(chain);
817 		}
818 		break;
819 	case HAMMER2_COMP_AUTOZERO:
820 		/*
821 		 * Check for zero-fill only
822 		 */
823 		hammer2_zero_check_and_write(bp, ip, parentp,
824 					     lbase, ioflag, pblksize,
825 					     mtid, errorp,
826 					     ip->meta.check_algo);
827 		break;
828 	case HAMMER2_COMP_LZ4:
829 	case HAMMER2_COMP_ZLIB:
830 	default:
831 		/*
832 		 * Check for zero-fill and attempt compression.
833 		 */
834 		hammer2_compress_and_write(bp, ip, parentp,
835 					   lbase, ioflag, pblksize,
836 					   mtid, errorp,
837 					   ip->meta.comp_algo,
838 					   ip->meta.check_algo);
839 		break;
840 	}
841 }
842 
843 /*
844  * Helper
845  *
846  * Generic function that will perform the compression in compression
847  * write path. The compression algorithm is determined by the settings
848  * obtained from inode.
849  */
850 static
851 void
852 hammer2_compress_and_write(struct buf *bp, hammer2_inode_t *ip,
853 	hammer2_chain_t **parentp,
854 	hammer2_key_t lbase, int ioflag, int pblksize,
855 	hammer2_tid_t mtid, int *errorp, int comp_algo, int check_algo)
856 {
857 	hammer2_chain_t *chain;
858 	int comp_size;
859 	int comp_block_size;
860 	char *comp_buffer;
861 	char *data;
862 
863 	if (test_block_zeros(bp->b_data, pblksize)) {
864 		zero_write(bp, ip, parentp, lbase, mtid, errorp);
865 		return;
866 	}
867 
868 	comp_size = 0;
869 	comp_buffer = NULL;
870 
871 	KKASSERT(pblksize / 2 <= 32768);
872 
873 	if (ip->comp_heuristic < 8 || (ip->comp_heuristic & 7) == 0) {
874 		z_stream strm_compress;
875 		int comp_level;
876 		int ret;
877 
878 		switch(HAMMER2_DEC_ALGO(comp_algo)) {
879 		case HAMMER2_COMP_LZ4:
880 			comp_buffer = objcache_get(cache_buffer_write,
881 						   M_INTWAIT);
882 			comp_size = LZ4_compress_limitedOutput(
883 					bp->b_data,
884 					&comp_buffer[sizeof(int)],
885 					pblksize,
886 					pblksize / 2 - sizeof(int));
887 			/*
888 			 * We need to prefix with the size, LZ4
889 			 * doesn't do it for us.  Add the related
890 			 * overhead.
891 			 */
892 			*(int *)comp_buffer = comp_size;
893 			if (comp_size)
894 				comp_size += sizeof(int);
895 			break;
896 		case HAMMER2_COMP_ZLIB:
897 			comp_level = HAMMER2_DEC_LEVEL(comp_algo);
898 			if (comp_level == 0)
899 				comp_level = 6;	/* default zlib compression */
900 			else if (comp_level < 6)
901 				comp_level = 6;
902 			else if (comp_level > 9)
903 				comp_level = 9;
904 			ret = deflateInit(&strm_compress, comp_level);
905 			if (ret != Z_OK) {
906 				kprintf("HAMMER2 ZLIB: fatal error "
907 					"on deflateInit.\n");
908 			}
909 
910 			comp_buffer = objcache_get(cache_buffer_write,
911 						   M_INTWAIT);
912 			strm_compress.next_in = bp->b_data;
913 			strm_compress.avail_in = pblksize;
914 			strm_compress.next_out = comp_buffer;
915 			strm_compress.avail_out = pblksize / 2;
916 			ret = deflate(&strm_compress, Z_FINISH);
917 			if (ret == Z_STREAM_END) {
918 				comp_size = pblksize / 2 -
919 					    strm_compress.avail_out;
920 			} else {
921 				comp_size = 0;
922 			}
923 			ret = deflateEnd(&strm_compress);
924 			break;
925 		default:
926 			kprintf("Error: Unknown compression method.\n");
927 			kprintf("Comp_method = %d.\n", comp_algo);
928 			break;
929 		}
930 	}
931 
932 	if (comp_size == 0) {
933 		/*
934 		 * compression failed or turned off
935 		 */
936 		comp_block_size = pblksize;	/* safety */
937 		if (++ip->comp_heuristic > 128)
938 			ip->comp_heuristic = 8;
939 	} else {
940 		/*
941 		 * compression succeeded
942 		 */
943 		ip->comp_heuristic = 0;
944 		if (comp_size <= 1024) {
945 			comp_block_size = 1024;
946 		} else if (comp_size <= 2048) {
947 			comp_block_size = 2048;
948 		} else if (comp_size <= 4096) {
949 			comp_block_size = 4096;
950 		} else if (comp_size <= 8192) {
951 			comp_block_size = 8192;
952 		} else if (comp_size <= 16384) {
953 			comp_block_size = 16384;
954 		} else if (comp_size <= 32768) {
955 			comp_block_size = 32768;
956 		} else {
957 			panic("hammer2: WRITE PATH: "
958 			      "Weird comp_size value.");
959 			/* NOT REACHED */
960 			comp_block_size = pblksize;
961 		}
962 
963 		/*
964 		 * Must zero the remainder or dedup (which operates on a
965 		 * physical block basis) will not find matches.
966 		 */
967 		if (comp_size < comp_block_size) {
968 			bzero(comp_buffer + comp_size,
969 			      comp_block_size - comp_size);
970 		}
971 	}
972 
973 	/*
974 	 * Assign physical storage, data will be set to NULL if a live-dedup
975 	 * was successful.
976 	 */
977 	data = comp_size ? comp_buffer : bp->b_data;
978 	chain = hammer2_assign_physical(ip, parentp, lbase, comp_block_size,
979 					mtid, &data, errorp);
980 
981 	if (*errorp) {
982 		kprintf("WRITE PATH: An error occurred while "
983 			"assigning physical space.\n");
984 		KKASSERT(chain == NULL);
985 		goto done;
986 	}
987 
988 	if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
989 		hammer2_inode_data_t *wipdata;
990 
991 		hammer2_chain_modify_ip(ip, chain, mtid, 0);
992 		wipdata = &chain->data->ipdata;
993 		KKASSERT(wipdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA);
994 		KKASSERT(bp->b_loffset == 0);
995 		bcopy(bp->b_data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
996 		++hammer2_iod_file_wembed;
997 	} else if (data == NULL) {
998 		/*
999 		 * Live deduplication, a copy of the data is already present
1000 		 * on the media.
1001 		 */
1002 		char *bdata;
1003 
1004 		if (comp_size) {
1005 			chain->bref.methods =
1006 				HAMMER2_ENC_COMP(comp_algo) +
1007 				HAMMER2_ENC_CHECK(check_algo);
1008 		} else {
1009 			chain->bref.methods =
1010 				HAMMER2_ENC_COMP(
1011 					HAMMER2_COMP_NONE) +
1012 				HAMMER2_ENC_CHECK(check_algo);
1013 		}
1014 		bdata = comp_size ? comp_buffer : bp->b_data;
1015 		hammer2_chain_setcheck(chain, bdata);
1016 		atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1017 	} else {
1018 		hammer2_io_t *dio;
1019 		char *bdata;
1020 
1021 		KKASSERT(chain->flags & HAMMER2_CHAIN_MODIFIED);
1022 
1023 		switch(chain->bref.type) {
1024 		case HAMMER2_BREF_TYPE_INODE:
1025 			panic("hammer2_write_bp: unexpected inode\n");
1026 			break;
1027 		case HAMMER2_BREF_TYPE_DATA:
1028 			/*
1029 			 * Optimize out the read-before-write
1030 			 * if possible.
1031 			 */
1032 			*errorp = hammer2_io_newnz(chain->hmp,
1033 						   chain->bref.type,
1034 						   chain->bref.data_off,
1035 						   chain->bytes,
1036 						   &dio);
1037 			if (*errorp) {
1038 				hammer2_io_brelse(&dio);
1039 				kprintf("hammer2: WRITE PATH: "
1040 					"dbp bread error\n");
1041 				break;
1042 			}
1043 			bdata = hammer2_io_data(dio, chain->bref.data_off);
1044 
1045 			/*
1046 			 * When loading the block make sure we don't
1047 			 * leave garbage after the compressed data.
1048 			 */
1049 			if (comp_size) {
1050 				chain->bref.methods =
1051 					HAMMER2_ENC_COMP(comp_algo) +
1052 					HAMMER2_ENC_CHECK(check_algo);
1053 				bcopy(comp_buffer, bdata, comp_size);
1054 			} else {
1055 				chain->bref.methods =
1056 					HAMMER2_ENC_COMP(
1057 						HAMMER2_COMP_NONE) +
1058 					HAMMER2_ENC_CHECK(check_algo);
1059 				bcopy(bp->b_data, bdata, pblksize);
1060 			}
1061 
1062 			/*
1063 			 * The flush code doesn't calculate check codes for
1064 			 * file data (doing so can result in excessive I/O),
1065 			 * so we do it here.
1066 			 */
1067 			hammer2_chain_setcheck(chain, bdata);
1068 			hammer2_dedup_record(chain, bdata);
1069 
1070 			/*
1071 			 * Device buffer is now valid, chain is no longer in
1072 			 * the initial state.
1073 			 *
1074 			 * (No blockref table worries with file data)
1075 			 */
1076 			atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1077 
1078 			/* Now write the related bdp. */
1079 			if (ioflag & IO_SYNC) {
1080 				/*
1081 				 * Synchronous I/O requested.
1082 				 */
1083 				hammer2_io_bwrite(&dio);
1084 			/*
1085 			} else if ((ioflag & IO_DIRECT) &&
1086 				   loff + n == pblksize) {
1087 				hammer2_io_bdwrite(&dio);
1088 			*/
1089 			} else if (ioflag & IO_ASYNC) {
1090 				hammer2_io_bawrite(&dio);
1091 			} else {
1092 				hammer2_io_bdwrite(&dio);
1093 			}
1094 			break;
1095 		default:
1096 			panic("hammer2_write_bp: bad chain type %d\n",
1097 				chain->bref.type);
1098 			/* NOT REACHED */
1099 			break;
1100 		}
1101 	}
1102 done:
1103 	if (chain) {
1104 		hammer2_chain_unlock(chain);
1105 		hammer2_chain_drop(chain);
1106 	}
1107 	if (comp_buffer)
1108 		objcache_put(cache_buffer_write, comp_buffer);
1109 }
1110 
1111 /*
1112  * Helper
1113  *
1114  * Function that performs zero-checking and writing without compression,
1115  * it corresponds to default zero-checking path.
1116  */
1117 static
1118 void
1119 hammer2_zero_check_and_write(struct buf *bp, hammer2_inode_t *ip,
1120 	hammer2_chain_t **parentp,
1121 	hammer2_key_t lbase, int ioflag, int pblksize,
1122 	hammer2_tid_t mtid, int *errorp,
1123 	int check_algo)
1124 {
1125 	hammer2_chain_t *chain;
1126 	char *data = bp->b_data;
1127 
1128 	if (test_block_zeros(bp->b_data, pblksize)) {
1129 		zero_write(bp, ip, parentp, lbase, mtid, errorp);
1130 	} else {
1131 		chain = hammer2_assign_physical(ip, parentp, lbase, pblksize,
1132 						mtid, &data, errorp);
1133 		if (data) {
1134 			hammer2_write_bp(chain, bp, ioflag, pblksize,
1135 					 mtid, errorp, check_algo);
1136 		} /* else dedup occurred */
1137 		if (chain) {
1138 			hammer2_chain_unlock(chain);
1139 			hammer2_chain_drop(chain);
1140 		}
1141 	}
1142 }
1143 
1144 /*
1145  * Helper
1146  *
1147  * A function to test whether a block of data contains only zeros,
1148  * returns TRUE (non-zero) if the block is all zeros.
1149  */
1150 static
1151 int
1152 test_block_zeros(const char *buf, size_t bytes)
1153 {
1154 	size_t i;
1155 
1156 	for (i = 0; i < bytes; i += sizeof(long)) {
1157 		if (*(const long *)(buf + i) != 0)
1158 			return (0);
1159 	}
1160 	return (1);
1161 }
1162 
1163 /*
1164  * Helper
1165  *
1166  * Function to "write" a block that contains only zeros.
1167  */
1168 static
1169 void
1170 zero_write(struct buf *bp, hammer2_inode_t *ip,
1171 	   hammer2_chain_t **parentp,
1172 	   hammer2_key_t lbase, hammer2_tid_t mtid, int *errorp)
1173 {
1174 	hammer2_chain_t *chain;
1175 	hammer2_key_t key_dummy;
1176 	int cache_index = -1;
1177 
1178 	*errorp = 0;
1179 	chain = hammer2_chain_lookup(parentp, &key_dummy,
1180 				     lbase, lbase,
1181 				     &cache_index,
1182 				     HAMMER2_LOOKUP_NODATA);
1183 	if (chain) {
1184 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
1185 			hammer2_inode_data_t *wipdata;
1186 
1187 			hammer2_chain_modify_ip(ip, chain, mtid, 0);
1188 			wipdata = &chain->data->ipdata;
1189 			KKASSERT(wipdata->meta.op_flags &
1190 				 HAMMER2_OPFLAG_DIRECTDATA);
1191 			KKASSERT(bp->b_loffset == 0);
1192 			bzero(wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1193 			++hammer2_iod_file_wembed;
1194 		} else {
1195 			hammer2_chain_delete(*parentp, chain,
1196 					     mtid, HAMMER2_DELETE_PERMANENT);
1197 			++hammer2_iod_file_wzero;
1198 		}
1199 		hammer2_chain_unlock(chain);
1200 		hammer2_chain_drop(chain);
1201 	} else {
1202 		++hammer2_iod_file_wzero;
1203 	}
1204 }
1205 
1206 /*
1207  * Helper
1208  *
1209  * Function to write the data as it is, without performing any sort of
1210  * compression. This function is used in path without compression and
1211  * default zero-checking path.
1212  */
1213 static
1214 void
1215 hammer2_write_bp(hammer2_chain_t *chain, struct buf *bp, int ioflag,
1216 		 int pblksize,
1217 		 hammer2_tid_t mtid, int *errorp, int check_algo)
1218 {
1219 	hammer2_inode_data_t *wipdata;
1220 	hammer2_io_t *dio;
1221 	char *bdata;
1222 	int error;
1223 
1224 	error = 0;	/* XXX TODO below */
1225 
1226 	KKASSERT(chain->flags & HAMMER2_CHAIN_MODIFIED);
1227 
1228 	switch(chain->bref.type) {
1229 	case HAMMER2_BREF_TYPE_INODE:
1230 		wipdata = &chain->data->ipdata;
1231 		KKASSERT(wipdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA);
1232 		KKASSERT(bp->b_loffset == 0);
1233 		bcopy(bp->b_data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1234 		error = 0;
1235 		++hammer2_iod_file_wembed;
1236 		break;
1237 	case HAMMER2_BREF_TYPE_DATA:
1238 		error = hammer2_io_newnz(chain->hmp,
1239 					 chain->bref.type,
1240 					 chain->bref.data_off,
1241 					 chain->bytes, &dio);
1242 		if (error) {
1243 			hammer2_io_bqrelse(&dio);
1244 			kprintf("hammer2: WRITE PATH: "
1245 				"dbp bread error\n");
1246 			break;
1247 		}
1248 		bdata = hammer2_io_data(dio, chain->bref.data_off);
1249 
1250 		chain->bref.methods = HAMMER2_ENC_COMP(HAMMER2_COMP_NONE) +
1251 				      HAMMER2_ENC_CHECK(check_algo);
1252 		bcopy(bp->b_data, bdata, chain->bytes);
1253 
1254 		/*
1255 		 * The flush code doesn't calculate check codes for
1256 		 * file data (doing so can result in excessive I/O),
1257 		 * so we do it here.
1258 		 */
1259 		hammer2_chain_setcheck(chain, bdata);
1260 		hammer2_dedup_record(chain, bdata);
1261 
1262 		/*
1263 		 * Device buffer is now valid, chain is no longer in
1264 		 * the initial state.
1265 		 *
1266 		 * (No blockref table worries with file data)
1267 		 */
1268 		atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1269 
1270 		if (ioflag & IO_SYNC) {
1271 			/*
1272 			 * Synchronous I/O requested.
1273 			 */
1274 			hammer2_io_bwrite(&dio);
1275 		/*
1276 		} else if ((ioflag & IO_DIRECT) &&
1277 			   loff + n == pblksize) {
1278 			hammer2_io_bdwrite(&dio);
1279 		*/
1280 		} else if (ioflag & IO_ASYNC) {
1281 			hammer2_io_bawrite(&dio);
1282 		} else {
1283 			hammer2_io_bdwrite(&dio);
1284 		}
1285 		break;
1286 	default:
1287 		panic("hammer2_write_bp: bad chain type %d\n",
1288 		      chain->bref.type);
1289 		/* NOT REACHED */
1290 		error = 0;
1291 		break;
1292 	}
1293 	KKASSERT(error == 0);	/* XXX TODO */
1294 	*errorp = error;
1295 }
1296 
1297 /*
1298  * LIVE DEDUP HEURISTIC
1299  *
1300  * WARNING! This code is SMP safe but the heuristic allows SMP collisions.
1301  *	    All fields must be loaded into locals and validated.
1302  *
1303  * WARNING! Should only be used for file data, hammer2_chain_modify() only
1304  *	    checks for the dedup case on data chains.  Also, dedup data can
1305  *	    only be recorded for committed chains (so NOT strategy writes
1306  *	    which can undergo further modification after the fact!).
1307  */
1308 void
1309 hammer2_dedup_record(hammer2_chain_t *chain, char *data)
1310 {
1311 	hammer2_dev_t *hmp;
1312 	hammer2_dedup_t *dedup;
1313 	uint64_t crc;
1314 	int best = 0;
1315 	int i;
1316 	int dticks;
1317 
1318 	if (hammer2_dedup_enable == 0)
1319 		return;
1320 
1321 	/*
1322 	 * Only committed data can be recorded for de-duplication, otherwise
1323 	 * the contents may change out from under us.  So, on read if the
1324 	 * chain is not modified, and on flush when the chain is committed.
1325 	 */
1326 	if ((chain->flags &
1327 	    (HAMMER2_CHAIN_MODIFIED | HAMMER2_CHAIN_INITIAL)) == 0) {
1328 		return;
1329 	}
1330 
1331 
1332 	hmp = chain->hmp;
1333 
1334 	switch(HAMMER2_DEC_CHECK(chain->bref.methods)) {
1335 	case HAMMER2_CHECK_ISCSI32:
1336 		/*
1337 		 * XXX use the built-in crc (the dedup lookup sequencing
1338 		 * needs to be fixed so the check code is already present
1339 		 * when dedup_lookup is called)
1340 		 */
1341 #if 0
1342 		crc = (uint64_t)(uint32_t)chain->bref.check.iscsi32.value;
1343 #endif
1344 		crc = XXH64(data, chain->bytes, XXH_HAMMER2_SEED);
1345 		break;
1346 	case HAMMER2_CHECK_XXHASH64:
1347 		crc = chain->bref.check.xxhash64.value;
1348 		break;
1349 	case HAMMER2_CHECK_SHA192:
1350 		/*
1351 		 * XXX use the built-in crc (the dedup lookup sequencing
1352 		 * needs to be fixed so the check code is already present
1353 		 * when dedup_lookup is called)
1354 		 */
1355 #if 0
1356 		crc = ((uint64_t *)chain->bref.check.sha192.data)[0] ^
1357 		      ((uint64_t *)chain->bref.check.sha192.data)[1] ^
1358 		      ((uint64_t *)chain->bref.check.sha192.data)[2];
1359 #endif
1360 		crc = XXH64(data, chain->bytes, XXH_HAMMER2_SEED);
1361 		break;
1362 	default:
1363 		/*
1364 		 * Cannot dedup without a check code
1365 		 *
1366 		 * NOTE: In particular, CHECK_NONE allows a sector to be
1367 		 *	 overwritten without copy-on-write, recording
1368 		 *	 a dedup block for a CHECK_NONE object would be
1369 		 *	 a disaster!
1370 		 */
1371 		return;
1372 	}
1373 	dedup = &hmp->heur_dedup[crc & (HAMMER2_DEDUP_HEUR_MASK & ~3)];
1374 	for (i = 0; i < 4; ++i) {
1375 		if (dedup[i].data_crc == crc) {
1376 			best = i;
1377 			break;
1378 		}
1379 		dticks = (int)(dedup[i].ticks - dedup[best].ticks);
1380 		if (dticks < 0 || dticks > hz * 60 * 30)
1381 			best = i;
1382 	}
1383 	dedup += best;
1384 	if (hammer2_debug & 0x40000) {
1385 		kprintf("REC %04x %016jx %016jx\n",
1386 			(int)(dedup - hmp->heur_dedup),
1387 			crc,
1388 			chain->bref.data_off);
1389 	}
1390 	dedup->ticks = ticks;
1391 	dedup->data_off = chain->bref.data_off;
1392 	dedup->data_crc = crc;
1393 	atomic_set_int(&chain->flags, HAMMER2_CHAIN_DEDUP);
1394 }
1395 
1396 static
1397 hammer2_off_t
1398 hammer2_dedup_lookup(hammer2_dev_t *hmp, char **datap, int pblksize)
1399 {
1400 	hammer2_dedup_t *dedup;
1401 	hammer2_io_t *dio;
1402 	hammer2_off_t off;
1403 	uint64_t crc;
1404 	char *data;
1405 	int i;
1406 
1407 	if (hammer2_dedup_enable == 0)
1408 		return 0;
1409 	data = *datap;
1410 	if (data == NULL)
1411 		return 0;
1412 
1413 	/*
1414 	 * XXX use the built-in crc (the dedup lookup sequencing
1415 	 * needs to be fixed so the check code is already present
1416 	 * when dedup_lookup is called)
1417 	 */
1418 	crc = XXH64(data, pblksize, XXH_HAMMER2_SEED);
1419 	dedup = &hmp->heur_dedup[crc & (HAMMER2_DEDUP_HEUR_MASK & ~3)];
1420 
1421 	if (hammer2_debug & 0x40000) {
1422 		kprintf("LOC %04x/4 %016jx\n",
1423 			(int)(dedup - hmp->heur_dedup),
1424 			crc);
1425 	}
1426 
1427 	for (i = 0; i < 4; ++i) {
1428 		off = dedup[i].data_off;
1429 		cpu_ccfence();
1430 		if (dedup[i].data_crc != crc)
1431 			continue;
1432 		if ((1 << (int)(off & HAMMER2_OFF_MASK_RADIX)) != pblksize)
1433 			continue;
1434 		dio = hammer2_io_getquick(hmp, off, pblksize);
1435 		if (dio &&
1436 		    bcmp(data, hammer2_io_data(dio, off), pblksize) == 0) {
1437 			/*
1438 			 * Make sure the INVALOK flag is cleared to prevent
1439 			 * the possibly-dirty bp from being invalidated now
1440 			 * that we are using it as part of a de-dup operation.
1441 			 */
1442 			if (hammer2_debug & 0x40000) {
1443 				kprintf("DEDUP SUCCESS %016jx\n",
1444 					(intmax_t)off);
1445 			}
1446 			atomic_clear_64(&dio->refs, HAMMER2_DIO_INVALOK);
1447 			hammer2_io_putblk(&dio);
1448 			*datap = NULL;
1449 			dedup[i].ticks = ticks;	/* update use */
1450 			++hammer2_iod_file_wdedup;
1451 
1452 			return off;		/* RETURN */
1453 		}
1454 		if (dio)
1455 			hammer2_io_putblk(&dio);
1456 	}
1457 	return 0;
1458 }
1459 
1460 /*
1461  * Poof.  Races are ok, if someone gets in and reuses a dedup offset
1462  * before or while we are clearing it they will also recover the freemap
1463  * entry (set it to fully allocated), so a bulkfree race can only set it
1464  * to a possibly-free state.
1465  *
1466  * XXX ok, well, not really sure races are ok but going to run with it
1467  *     for the moment.
1468  */
1469 void
1470 hammer2_dedup_clear(hammer2_dev_t *hmp)
1471 {
1472 	int i;
1473 
1474 	for (i = 0; i < HAMMER2_DEDUP_HEUR_SIZE; ++i) {
1475 		hmp->heur_dedup[i].data_off = 0;
1476 		hmp->heur_dedup[i].ticks = ticks - 1;
1477 	}
1478 }
1479