1 /*
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 2022 Tomohiro Kusumi <tkusumi@netbsd.org>
5  * Copyright (c) 2011-2022 The DragonFly Project.  All rights reserved.
6  *
7  * This code is derived from software contributed to The DragonFly Project
8  * by Matthew Dillon <dillon@dragonflybsd.org>
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  *
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in
18  *    the documentation and/or other materials provided with the
19  *    distribution.
20  * 3. Neither the name of The DragonFly Project nor the names of its
21  *    contributors may be used to endorse or promote products derived
22  *    from this software without specific, prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
27  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
28  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
29  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
30  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
31  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
32  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
33  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
34  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  */
37 /*
38  * This module handles low level logical file I/O (strategy) which backs
39  * the logical buffer cache.
40  *
41  * [De]compression, zero-block, check codes, and buffer cache operations
42  * for file data is handled here.
43  *
44  * Live dedup makes its home here as well.
45  */
46 
47 /*
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/kernel.h>
51 #include <sys/buf.h>
52 #include <sys/proc.h>
53 #include <sys/mount.h>
54 #include <sys/vnode.h>
55 #include <sys/objcache.h>
56 */
57 
58 #include "hammer2.h"
59 #include "hammer2_lz4.h"
60 
61 #include "zlib/hammer2_zlib.h"
62 
63 /*
64 struct objcache *cache_buffer_read;
65 struct objcache *cache_buffer_write;
66 */
67 
68 /*
69  * Strategy code (async logical file buffer I/O from system)
70  *
71  * Except for the transaction init (which should normally not block),
72  * we essentially run the strategy operation asynchronously via a XOP.
73  *
74  * WARNING! The XOP deals with buffer synchronization.  It is not synchronized
75  *	    to the current cpu.
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 int hammer2_strategy_read(struct vop_strategy_args *ap);
87 static int hammer2_strategy_write(struct vop_strategy_args *ap);
88 static void hammer2_strategy_read_completion(hammer2_chain_t *focus,
89 				const char *data, struct bio *bio);
90 
91 static hammer2_off_t hammer2_dedup_lookup(hammer2_dev_t *hmp,
92 			char **datap, int pblksize);
93 
94 int
95 hammer2_vop_strategy(struct vop_strategy_args *ap)
96 {
97 	struct bio *biop;
98 	struct m_buf *bp;
99 	int error;
100 
101 	biop = ap->a_bio;
102 	bp = biop->bio_buf;
103 
104 	switch(bp->b_cmd) {
105 	case BUF_CMD_READ:
106 		error = hammer2_strategy_read(ap);
107 		break;
108 	case BUF_CMD_WRITE:
109 		error = hammer2_strategy_write(ap);
110 		break;
111 	default:
112 		assert(0);
113 		/*
114 		bp->b_error = error = EINVAL;
115 		bp->b_flags |= B_ERROR;
116 		biodone(biop);
117 		*/
118 		break;
119 	}
120 	return (error);
121 }
122 
123 /*
124  * Return the largest contiguous physical disk range for the logical
125  * request, in bytes.
126  *
127  * (struct m_vnode *vp, off_t loffset, off_t *doffsetp, int *runp, int *runb)
128  *
129  * Basically disabled, the logical buffer write thread has to deal with
130  * buffers one-at-a-time.  Note that this should not prevent cluster_read()
131  * from reading-ahead, it simply prevents it from trying form a single
132  * cluster buffer for the logical request.  H2 already uses 64KB buffers!
133  */
134 int
135 hammer2_vop_bmap(struct vop_bmap_args *ap)
136 {
137 	*ap->a_doffsetp = NOOFFSET;
138 	if (ap->a_runp)
139 		*ap->a_runp = 0;
140 	if (ap->a_runb)
141 		*ap->a_runb = 0;
142 	return (EOPNOTSUPP);
143 }
144 
145 /****************************************************************************
146  *				READ SUPPORT				    *
147  ****************************************************************************/
148 /*
149  * Callback used in read path in case that a block is compressed with LZ4.
150  */
151 static
152 void
153 hammer2_decompress_LZ4_callback(const char *data, u_int bytes, struct bio *bio)
154 {
155 	struct m_buf *bp;
156 	char *compressed_buffer;
157 	int compressed_size;
158 	int result;
159 
160 	bp = bio->bio_buf;
161 
162 #if 0
163 	if bio->bio_caller_info2.index &&
164 	      bio->bio_caller_info1.uvalue32 !=
165 	      crc32(bp->b_data, bp->b_bufsize) --- return error
166 #endif
167 
168 	KKASSERT(bp->b_bufsize <= HAMMER2_PBUFSIZE);
169 	compressed_size = *(const int *)data;
170 	KKASSERT((uint32_t)compressed_size <= bytes - sizeof(int));
171 
172 	compressed_buffer = ecalloc(1, 65536);
173 	result = LZ4_decompress_safe(__DECONST(char *, &data[sizeof(int)]),
174 				     compressed_buffer,
175 				     compressed_size,
176 				     bp->b_bufsize);
177 	if (result < 0) {
178 		kprintf("READ PATH: Error during decompression."
179 			"bio %016jx/%d\n",
180 			(intmax_t)bio->bio_offset, bytes);
181 		/* make sure it isn't random garbage */
182 		bzero(compressed_buffer, bp->b_bufsize);
183 	}
184 	KKASSERT(result <= bp->b_bufsize);
185 	bcopy(compressed_buffer, bp->b_data, bp->b_bufsize);
186 	if (result < bp->b_bufsize)
187 		bzero(bp->b_data + result, bp->b_bufsize - result);
188 	free(compressed_buffer);
189 	/*
190 	bp->b_resid = 0;
191 	bp->b_flags |= B_AGE;
192 	*/
193 }
194 
195 /*
196  * Callback used in read path in case that a block is compressed with ZLIB.
197  * It is almost identical to LZ4 callback, so in theory they can be unified,
198  * but we didn't want to make changes in bio structure for that.
199  */
200 static
201 void
202 hammer2_decompress_ZLIB_callback(const char *data, u_int bytes, struct bio *bio)
203 {
204 	struct m_buf *bp;
205 	char *compressed_buffer;
206 	z_stream strm_decompress;
207 	int result;
208 	int ret;
209 
210 	bp = bio->bio_buf;
211 
212 	KKASSERT(bp->b_bufsize <= HAMMER2_PBUFSIZE);
213 	strm_decompress.avail_in = 0;
214 	strm_decompress.next_in = Z_NULL;
215 
216 	ret = inflateInit(&strm_decompress);
217 
218 	if (ret != Z_OK)
219 		kprintf("HAMMER2 ZLIB: Fatal error in inflateInit.\n");
220 
221 	compressed_buffer = ecalloc(1, 65536);
222 	strm_decompress.next_in = __DECONST(char *, data);
223 
224 	/* XXX supply proper size, subset of device bp */
225 	strm_decompress.avail_in = bytes;
226 	strm_decompress.next_out = compressed_buffer;
227 	strm_decompress.avail_out = bp->b_bufsize;
228 
229 	ret = inflate(&strm_decompress, Z_FINISH);
230 	if (ret != Z_STREAM_END) {
231 		kprintf("HAMMER2 ZLIB: Fatal error during decompression.\n");
232 		bzero(compressed_buffer, bp->b_bufsize);
233 	}
234 	bcopy(compressed_buffer, bp->b_data, bp->b_bufsize);
235 	result = bp->b_bufsize - strm_decompress.avail_out;
236 	if (result < bp->b_bufsize)
237 		bzero(bp->b_data + result, strm_decompress.avail_out);
238 	free(compressed_buffer);
239 	ret = inflateEnd(&strm_decompress);
240 
241 	/*
242 	bp->b_resid = 0;
243 	bp->b_flags |= B_AGE;
244 	*/
245 }
246 
247 /*
248  * Logical buffer I/O, async read.
249  */
250 static
251 int
252 hammer2_strategy_read(struct vop_strategy_args *ap)
253 {
254 	hammer2_xop_strategy_t *xop;
255 	struct bio *bio;
256 	hammer2_inode_t *ip;
257 	hammer2_key_t lbase;
258 
259 	bio = ap->a_bio;
260 	ip = VTOI(ap->a_vp);
261 
262 	lbase = bio->bio_offset;
263 	KKASSERT(((int)lbase & HAMMER2_PBUFMASK) == 0);
264 
265 	xop = hammer2_xop_alloc(ip, HAMMER2_XOP_STRATEGY);
266 	xop->finished = 0;
267 	xop->bio = bio;
268 	xop->lbase = lbase;
269 	hammer2_mtx_init(&xop->lock, "h2bior");
270 	hammer2_xop_start(&xop->head, &hammer2_strategy_read_desc);
271 	/* asynchronous completion */
272 
273 	return(0);
274 }
275 
276 /*
277  * Per-node XOP (threaded), do a synchronous lookup of the chain and
278  * its data.  The frontend is asynchronous, so we are also responsible
279  * for racing to terminate the frontend.
280  */
281 void
282 hammer2_xop_strategy_read(hammer2_xop_t *arg, void *scratch, int clindex)
283 {
284 	hammer2_xop_strategy_t *xop = &arg->xop_strategy;
285 	hammer2_chain_t *parent;
286 	hammer2_chain_t *chain;
287 	hammer2_chain_t *focus;
288 	hammer2_key_t key_dummy;
289 	hammer2_key_t lbase;
290 	struct bio *bio;
291 	struct m_buf *bp;
292 	const char *data;
293 	int error;
294 
295 	/*
296 	 * Note that we can race completion of the bio supplied by
297 	 * the front-end so we cannot access it until we determine
298 	 * that we are the ones finishing it up.
299 	 */
300 	lbase = xop->lbase;
301 
302 	/*
303 	 * This is difficult to optimize.  The logical buffer might be
304 	 * partially dirty (contain dummy zero-fill pages), which would
305 	 * mess up our crc calculation if we were to try a direct read.
306 	 * So for now we always double-buffer through the underlying
307 	 * storage.
308 	 *
309 	 * If not for the above problem we could conditionalize on
310 	 * (1) 64KB buffer, (2) one chain (not multi-master) and
311 	 * (3) !hammer2_double_buffer, and issue a direct read into the
312 	 * logical buffer.
313 	 */
314 	parent = hammer2_inode_chain(xop->head.ip1, clindex,
315 				     HAMMER2_RESOLVE_ALWAYS |
316 				     HAMMER2_RESOLVE_SHARED);
317 	if (parent) {
318 		chain = hammer2_chain_lookup(&parent, &key_dummy,
319 					     lbase, lbase,
320 					     &error,
321 					     HAMMER2_LOOKUP_ALWAYS |
322 					     HAMMER2_LOOKUP_SHARED);
323 		if (chain)
324 			error = chain->error;
325 	} else {
326 		error = HAMMER2_ERROR_EIO;
327 		chain = NULL;
328 	}
329 	error = hammer2_xop_feed(&xop->head, chain, clindex, error);
330 	if (chain) {
331 		hammer2_chain_unlock(chain);
332 		hammer2_chain_drop(chain);
333 	}
334 	if (parent) {
335 		hammer2_chain_unlock(parent);
336 		hammer2_chain_drop(parent);
337 	}
338 	chain = NULL;	/* safety */
339 	parent = NULL;	/* safety */
340 
341 	/*
342 	 * Race to finish the frontend.  First-to-complete.  bio is only
343 	 * valid if we are determined to be the ones able to complete
344 	 * the operation.
345 	 */
346 	if (xop->finished)
347 		return;
348 	hammer2_mtx_ex(&xop->lock);
349 	if (xop->finished) {
350 		hammer2_mtx_unlock(&xop->lock);
351 		return;
352 	}
353 	bio = xop->bio;
354 	bp = bio->bio_buf;
355 	bkvasync(bp);
356 
357 	/*
358 	 * Async operation has not completed and we now own the lock.
359 	 * Determine if we can complete the operation by issuing the
360 	 * frontend collection non-blocking.
361 	 *
362 	 * H2 double-buffers the data, setting B_NOTMETA on the logical
363 	 * buffer hints to the OS that the logical buffer should not be
364 	 * swapcached (since the device buffer can be).
365 	 *
366 	 * Also note that even for compressed data we would rather the
367 	 * kernel cache/swapcache device buffers more and (decompressed)
368 	 * logical buffers less, since that will significantly improve
369 	 * the amount of end-user data that can be cached.
370 	 *
371 	 * NOTE: The chain->data for xop->head.cluster.focus will be
372 	 *	 synchronized to the current cpu by xop_collect(),
373 	 *	 but other chains in the cluster might not be.
374 	 */
375 	error = hammer2_xop_collect(&xop->head, HAMMER2_XOP_COLLECT_NOWAIT);
376 
377 	switch(error) {
378 	case 0:
379 		xop->finished = 1;
380 		hammer2_mtx_unlock(&xop->lock);
381 		//bp->b_flags |= B_NOTMETA;
382 		focus = xop->head.cluster.focus;
383 		data = hammer2_xop_gdata(&xop->head)->buf;
384 		hammer2_strategy_read_completion(focus, data, xop->bio);
385 		hammer2_xop_pdata(&xop->head);
386 		//biodone(bio);
387 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
388 		break;
389 	case HAMMER2_ERROR_ENOENT:
390 		xop->finished = 1;
391 		hammer2_mtx_unlock(&xop->lock);
392 		/*
393 		bp->b_flags |= B_NOTMETA;
394 		bp->b_resid = 0;
395 		bp->b_error = 0;
396 		*/
397 		bzero(bp->b_data, bp->b_bcount);
398 		//biodone(bio);
399 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
400 		break;
401 	case HAMMER2_ERROR_EINPROGRESS:
402 		hammer2_mtx_unlock(&xop->lock);
403 		break;
404 	default:
405 		kprintf("xop_strategy_read: error %08x loff=%016jx\n",
406 			error, (intmax_t)bp->b_loffset);
407 		xop->finished = 1;
408 		hammer2_mtx_unlock(&xop->lock);
409 		assert(0);
410 		/*
411 		bp->b_flags |= B_ERROR;
412 		bp->b_error = EIO;
413 		biodone(bio);
414 		*/
415 		hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
416 		break;
417 	}
418 }
419 
420 static
421 void
422 hammer2_strategy_read_completion(hammer2_chain_t *focus, const char *data,
423 				 struct bio *bio)
424 {
425 	struct m_buf *bp = bio->bio_buf;
426 
427 	if (focus->bref.type == HAMMER2_BREF_TYPE_INODE) {
428 		/*
429 		 * Copy from in-memory inode structure.
430 		 */
431 		bcopy(((const 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 		/*
436 		bp->b_resid = 0;
437 		bp->b_error = 0;
438 		*/
439 	} else if (focus->bref.type == HAMMER2_BREF_TYPE_DATA) {
440 		/*
441 		 * Data is on-media, record for live dedup.  Release the
442 		 * chain (try to free it) when done.  The data is still
443 		 * cached by both the buffer cache in front and the
444 		 * block device behind us.  This leaves more room in the
445 		 * LRU chain cache for meta-data chains which we really
446 		 * want to retain.
447 		 *
448 		 * NOTE: Deduplication cannot be safely recorded for
449 		 *	 records without a check code.
450 		 */
451 		hammer2_dedup_record(focus, NULL, data);
452 		atomic_set_int(&focus->flags, HAMMER2_CHAIN_RELEASE);
453 
454 		/*
455 		 * Decompression and copy.
456 		 */
457 		switch (HAMMER2_DEC_COMP(focus->bref.methods)) {
458 		case HAMMER2_COMP_LZ4:
459 			hammer2_decompress_LZ4_callback(data, focus->bytes,
460 							bio);
461 			/* b_resid set by call */
462 			break;
463 		case HAMMER2_COMP_ZLIB:
464 			hammer2_decompress_ZLIB_callback(data, focus->bytes,
465 							 bio);
466 			/* b_resid set by call */
467 			break;
468 		case HAMMER2_COMP_NONE:
469 			KKASSERT(focus->bytes <= bp->b_bcount);
470 			bcopy(data, bp->b_data, focus->bytes);
471 			if (focus->bytes < bp->b_bcount) {
472 				bzero(bp->b_data + focus->bytes,
473 				      bp->b_bcount - focus->bytes);
474 			}
475 			/*
476 			bp->b_resid = 0;
477 			bp->b_error = 0;
478 			*/
479 			break;
480 		default:
481 			panic("hammer2_strategy_read_completion: "
482 			      "unknown compression type");
483 		}
484 	} else {
485 		panic("hammer2_strategy_read_completion: unknown bref type");
486 	}
487 }
488 
489 /****************************************************************************
490  *				WRITE SUPPORT				    *
491  ****************************************************************************/
492 
493 /*
494  * Functions for compression in threads,
495  * from hammer2_vnops.c
496  */
497 static void hammer2_write_file_core(char *data, hammer2_inode_t *ip,
498 				hammer2_chain_t **parentp,
499 				hammer2_key_t lbase, int ioflag, int pblksize,
500 				hammer2_tid_t mtid, int *errorp);
501 static void hammer2_compress_and_write(char *data, hammer2_inode_t *ip,
502 				hammer2_chain_t **parentp,
503 				hammer2_key_t lbase, int ioflag, int pblksize,
504 				hammer2_tid_t mtid, int *errorp,
505 				int comp_algo, int check_algo);
506 static void hammer2_zero_check_and_write(char *data, hammer2_inode_t *ip,
507 				hammer2_chain_t **parentp,
508 				hammer2_key_t lbase, int ioflag, int pblksize,
509 				hammer2_tid_t mtid, int *errorp,
510 				int check_algo);
511 static int test_block_zeros(const char *buf, size_t bytes);
512 static void zero_write(char *data, hammer2_inode_t *ip,
513 				hammer2_chain_t **parentp,
514 				hammer2_key_t lbase,
515 				hammer2_tid_t mtid, int *errorp);
516 static void hammer2_write_bp(hammer2_chain_t *chain, char *data,
517 				int ioflag, int pblksize,
518 				hammer2_tid_t mtid, int *errorp,
519 				int check_algo);
520 
521 int
522 hammer2_strategy_write(struct vop_strategy_args *ap)
523 {
524 	hammer2_xop_strategy_t *xop;
525 	hammer2_pfs_t *pmp;
526 	struct bio *bio;
527 	hammer2_inode_t *ip;
528 
529 	bio = ap->a_bio;
530 	ip = VTOI(ap->a_vp);
531 	pmp = ip->pmp;
532 
533 	atomic_set_int(&ip->flags, HAMMER2_INODE_DIRTYDATA);
534 	hammer2_lwinprog_ref(pmp);
535 	hammer2_trans_assert_strategy(pmp);
536 	hammer2_trans_init(pmp, HAMMER2_TRANS_BUFCACHE);
537 
538 	xop = hammer2_xop_alloc(ip, HAMMER2_XOP_MODIFYING |
539 				    HAMMER2_XOP_STRATEGY);
540 	xop->finished = 0;
541 	xop->bio = bio;
542 	xop->lbase = bio->bio_offset;
543 	hammer2_mtx_init(&xop->lock, "h2biow");
544 	hammer2_xop_start(&xop->head, &hammer2_strategy_write_desc);
545 	/* asynchronous completion */
546 
547 	hammer2_lwinprog_wait(pmp, hammer2_flush_pipe);
548 
549 	return(0);
550 }
551 
552 /*
553  * Per-node XOP (threaded).  Write the logical buffer to the media.
554  *
555  * This is a bit problematic because there may be multiple target and
556  * any of them may be able to release the bp.  In addition, if our
557  * particulr target is offline we don't want to block the bp (and thus
558  * the frontend).  To accomplish this we copy the data to the per-thr
559  * scratch buffer.
560  */
561 void
562 hammer2_xop_strategy_write(hammer2_xop_t *arg, void *scratch, int clindex)
563 {
564 	hammer2_xop_strategy_t *xop = &arg->xop_strategy;
565 	hammer2_chain_t *parent;
566 	hammer2_key_t lbase;
567 	hammer2_inode_t *ip;
568 	struct bio *bio;
569 	struct m_buf *bp;
570 	int error;
571 	int lblksize;
572 	int pblksize;
573 	char *bio_data;
574 
575 	/*
576 	 * We can only access the bp/bio if the frontend has not yet
577 	 * completed.
578 	 */
579 	if (xop->finished)
580 		return;
581 	hammer2_mtx_sh(&xop->lock);
582 	if (xop->finished) {
583 		hammer2_mtx_unlock(&xop->lock);
584 		return;
585 	}
586 
587 	lbase = xop->lbase;
588 	bio = xop->bio;			/* ephermal */
589 	bp = bio->bio_buf;		/* ephermal */
590 	ip = xop->head.ip1;		/* retained by ref */
591 	bio_data = scratch;
592 
593 	/* hammer2_trans_init(parent->hmp->spmp, HAMMER2_TRANS_BUFCACHE); */
594 
595 	lblksize = hammer2_calc_logical(ip, bio->bio_offset, &lbase, NULL);
596 	pblksize = hammer2_calc_physical(ip, lbase);
597 	bkvasync(bp);
598 	KKASSERT(lblksize <= MAXPHYS);
599 	bcopy(bp->b_data, bio_data, lblksize);
600 
601 	hammer2_mtx_unlock(&xop->lock);
602 	bp = NULL;	/* safety, illegal to access after unlock */
603 	bio = NULL;	/* safety, illegal to access after unlock */
604 
605 	/*
606 	 * Actual operation
607 	 */
608 	parent = hammer2_inode_chain(ip, clindex, HAMMER2_RESOLVE_ALWAYS);
609 	hammer2_write_file_core(bio_data, ip, &parent,
610 				lbase, IO_ASYNC, pblksize,
611 				xop->head.mtid, &error);
612 	if (parent) {
613 		hammer2_chain_unlock(parent);
614 		hammer2_chain_drop(parent);
615 		parent = NULL;	/* safety */
616 	}
617 	hammer2_xop_feed(&xop->head, NULL, clindex, error);
618 
619 	/*
620 	 * Try to complete the operation on behalf of the front-end.
621 	 */
622 	if (xop->finished)
623 		return;
624 	hammer2_mtx_ex(&xop->lock);
625 	if (xop->finished) {
626 		hammer2_mtx_unlock(&xop->lock);
627 		return;
628 	}
629 
630 	/*
631 	 * Async operation has not completed and we now own the lock.
632 	 * Determine if we can complete the operation by issuing the
633 	 * frontend collection non-blocking.
634 	 *
635 	 * H2 double-buffers the data, setting B_NOTMETA on the logical
636 	 * buffer hints to the OS that the logical buffer should not be
637 	 * swapcached (since the device buffer can be).
638 	 */
639 	error = hammer2_xop_collect(&xop->head, HAMMER2_XOP_COLLECT_NOWAIT);
640 
641 	if (error == HAMMER2_ERROR_EINPROGRESS) {
642 		hammer2_mtx_unlock(&xop->lock);
643 		return;
644 	}
645 
646 	/*
647 	 * Async operation has completed.
648 	 */
649 	xop->finished = 1;
650 	hammer2_mtx_unlock(&xop->lock);
651 
652 	bio = xop->bio;		/* now owned by us */
653 	bp = bio->bio_buf;	/* now owned by us */
654 
655 	if (error == HAMMER2_ERROR_ENOENT || error == 0) {
656 		/*
657 		bp->b_flags |= B_NOTMETA;
658 		bp->b_resid = 0;
659 		bp->b_error = 0;
660 		biodone(bio);
661 		*/
662 	} else {
663 		kprintf("xop_strategy_write: error %d loff=%016jx\n",
664 			error, (intmax_t)bp->b_loffset);
665 		assert(0);
666 		/*
667 		bp->b_flags |= B_ERROR;
668 		bp->b_error = EIO;
669 		biodone(bio);
670 		*/
671 	}
672 	hammer2_xop_retire(&xop->head, HAMMER2_XOPMASK_VOP);
673 	hammer2_trans_assert_strategy(ip->pmp);
674 	hammer2_lwinprog_drop(ip->pmp);
675 	hammer2_trans_done(ip->pmp, HAMMER2_TRANS_BUFCACHE);
676 }
677 
678 /*
679  * Wait for pending I/O to complete
680  */
681 void
682 hammer2_bioq_sync(hammer2_pfs_t *pmp)
683 {
684 	hammer2_lwinprog_wait(pmp, 0);
685 }
686 
687 /*
688  * Assign physical storage at (cparent, lbase), returning a suitable chain
689  * and setting *errorp appropriately.
690  *
691  * If no error occurs, the returned chain will be in a modified state.
692  *
693  * If an error occurs, the returned chain may or may not be NULL.  If
694  * not-null any chain->error (if not 0) will also be rolled up into *errorp.
695  * So the caller only needs to test *errorp.
696  *
697  * cparent can wind up being anything.
698  *
699  * If datap is not NULL, *datap points to the real data we intend to write.
700  * If we can dedup the storage location we set *datap to NULL to indicate
701  * to the caller that a dedup occurred.
702  *
703  * NOTE: Special case for data embedded in inode.
704  */
705 static
706 hammer2_chain_t *
707 hammer2_assign_physical(hammer2_inode_t *ip, hammer2_chain_t **parentp,
708 			hammer2_key_t lbase, int pblksize,
709 			hammer2_tid_t mtid, char **datap, int *errorp)
710 {
711 	hammer2_chain_t *chain;
712 	hammer2_key_t key_dummy;
713 	hammer2_off_t dedup_off;
714 	int pradix = hammer2_getradix(pblksize);
715 
716 	/*
717 	 * Locate the chain associated with lbase, return a locked chain.
718 	 * However, do not instantiate any data reference (which utilizes a
719 	 * device buffer) because we will be using direct IO via the
720 	 * logical buffer cache buffer.
721 	 */
722 	KKASSERT(pblksize >= HAMMER2_ALLOC_MIN);
723 
724 	chain = hammer2_chain_lookup(parentp, &key_dummy,
725 				     lbase, lbase,
726 				     errorp,
727 				     HAMMER2_LOOKUP_NODATA);
728 
729 	/*
730 	 * The lookup code should not return a DELETED chain to us, unless
731 	 * its a short-file embedded in the inode.  Then it is possible for
732 	 * the lookup to return a deleted inode.
733 	 */
734 	if (chain && (chain->flags & HAMMER2_CHAIN_DELETED) &&
735 	    chain->bref.type != HAMMER2_BREF_TYPE_INODE) {
736 		kprintf("assign physical deleted chain @ "
737 			"%016jx (%016jx.%02x) ip %016jx\n",
738 			lbase, chain->bref.data_off, chain->bref.type,
739 			ip->meta.inum);
740 		Debugger("bleh");
741 	}
742 
743 	if (chain == NULL) {
744 		/*
745 		 * We found a hole, create a new chain entry.
746 		 *
747 		 * NOTE: DATA chains are created without device backing
748 		 *	 store (nor do we want any).
749 		 */
750 		dedup_off = hammer2_dedup_lookup((*parentp)->hmp, datap,
751 						 pblksize);
752 		*errorp |= hammer2_chain_create(parentp, &chain, NULL, ip->pmp,
753 				       HAMMER2_ENC_CHECK(ip->meta.check_algo) |
754 				       HAMMER2_ENC_COMP(HAMMER2_COMP_NONE),
755 					        lbase, HAMMER2_PBUFRADIX,
756 					        HAMMER2_BREF_TYPE_DATA,
757 					        pblksize, mtid,
758 					        dedup_off, 0);
759 		if (chain == NULL)
760 			goto failed;
761 		/*ip->delta_dcount += pblksize;*/
762 	} else if (chain->error == 0) {
763 		switch (chain->bref.type) {
764 		case HAMMER2_BREF_TYPE_INODE:
765 			/*
766 			 * The data is embedded in the inode, which requires
767 			 * a bit more finess.
768 			 */
769 			*errorp |= hammer2_chain_modify_ip(ip, chain, mtid, 0);
770 			break;
771 		case HAMMER2_BREF_TYPE_DATA:
772 			dedup_off = hammer2_dedup_lookup(chain->hmp, datap,
773 							 pblksize);
774 			if (chain->bytes != pblksize) {
775 				*errorp |= hammer2_chain_resize(chain,
776 						     mtid, dedup_off,
777 						     pradix,
778 						     HAMMER2_MODIFY_OPTDATA);
779 				if (*errorp)
780 					break;
781 			}
782 
783 			/*
784 			 * DATA buffers must be marked modified whether the
785 			 * data is in a logical buffer or not.  We also have
786 			 * to make this call to fixup the chain data pointers
787 			 * after resizing in case this is an encrypted or
788 			 * compressed buffer.
789 			 */
790 			*errorp |= hammer2_chain_modify(chain, mtid, dedup_off,
791 						        HAMMER2_MODIFY_OPTDATA);
792 			break;
793 		default:
794 			panic("hammer2_assign_physical: bad type");
795 			/* NOT REACHED */
796 			break;
797 		}
798 	} else {
799 		*errorp = chain->error;
800 	}
801 	atomic_set_int(&ip->flags, HAMMER2_INODE_DIRTYDATA);
802 failed:
803 	return (chain);
804 }
805 
806 /*
807  * hammer2_write_file_core()
808  *
809  * The core write function which determines which path to take
810  * depending on compression settings.  We also have to locate the
811  * related chains so we can calculate and set the check data for
812  * the blockref.
813  */
814 static
815 void
816 hammer2_write_file_core(char *data, hammer2_inode_t *ip,
817 			hammer2_chain_t **parentp,
818 			hammer2_key_t lbase, int ioflag, int pblksize,
819 			hammer2_tid_t mtid, int *errorp)
820 {
821 	hammer2_chain_t *chain;
822 	char *bdata;
823 
824 	*errorp = 0;
825 
826 	switch(HAMMER2_DEC_ALGO(ip->meta.comp_algo)) {
827 	case HAMMER2_COMP_NONE:
828 		/*
829 		 * We have to assign physical storage to the buffer
830 		 * we intend to dirty or write now to avoid deadlocks
831 		 * in the strategy code later.
832 		 *
833 		 * This can return NOOFFSET for inode-embedded data.
834 		 * The strategy code will take care of it in that case.
835 		 */
836 		bdata = data;
837 		chain = hammer2_assign_physical(ip, parentp, lbase, pblksize,
838 						mtid, &bdata, errorp);
839 		if (*errorp) {
840 			/* skip modifications */
841 		} else if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
842 			hammer2_inode_data_t *wipdata;
843 
844 			wipdata = &chain->data->ipdata;
845 			KKASSERT(wipdata->meta.op_flags &
846 				 HAMMER2_OPFLAG_DIRECTDATA);
847 			bcopy(data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
848 			++hammer2_iod_file_wembed;
849 		} else if (bdata == NULL) {
850 			/*
851 			 * Copy of data already present on-media.
852 			 */
853 			chain->bref.methods =
854 				HAMMER2_ENC_COMP(HAMMER2_COMP_NONE) +
855 				HAMMER2_ENC_CHECK(ip->meta.check_algo);
856 			hammer2_chain_setcheck(chain, data);
857 			atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
858 		} else {
859 			hammer2_write_bp(chain, data, ioflag, pblksize,
860 					 mtid, errorp, ip->meta.check_algo);
861 		}
862 		if (chain) {
863 			hammer2_chain_unlock(chain);
864 			hammer2_chain_drop(chain);
865 		}
866 		break;
867 	case HAMMER2_COMP_AUTOZERO:
868 		/*
869 		 * Check for zero-fill only
870 		 */
871 		hammer2_zero_check_and_write(data, ip, parentp,
872 					     lbase, ioflag, pblksize,
873 					     mtid, errorp,
874 					     ip->meta.check_algo);
875 		break;
876 	case HAMMER2_COMP_LZ4:
877 	case HAMMER2_COMP_ZLIB:
878 	default:
879 		/*
880 		 * Check for zero-fill and attempt compression.
881 		 */
882 		hammer2_compress_and_write(data, ip, parentp,
883 					   lbase, ioflag, pblksize,
884 					   mtid, errorp,
885 					   ip->meta.comp_algo,
886 					   ip->meta.check_algo);
887 		break;
888 	}
889 }
890 
891 /*
892  * Helper
893  *
894  * Generic function that will perform the compression in compression
895  * write path. The compression algorithm is determined by the settings
896  * obtained from inode.
897  */
898 static
899 void
900 hammer2_compress_and_write(char *data, hammer2_inode_t *ip,
901 	hammer2_chain_t **parentp,
902 	hammer2_key_t lbase, int ioflag, int pblksize,
903 	hammer2_tid_t mtid, int *errorp, int comp_algo, int check_algo)
904 {
905 	hammer2_chain_t *chain;
906 	int comp_size;
907 	int comp_block_size;
908 	char *comp_buffer;
909 	char *bdata;
910 
911 	/*
912 	 * An all-zeros write creates a hole unless the check code
913 	 * is disabled.  When the check code is disabled all writes
914 	 * are done in-place, including any all-zeros writes.
915 	 *
916 	 * NOTE: A snapshot will still force a copy-on-write
917 	 *	 (see the HAMMER2_CHECK_NONE in hammer2_chain.c).
918 	 */
919 	if (check_algo != HAMMER2_CHECK_NONE &&
920 	    test_block_zeros(data, pblksize)) {
921 		zero_write(data, ip, parentp, lbase, mtid, errorp);
922 		return;
923 	}
924 
925 	/*
926 	 * Compression requested.  Try to compress the block.  We store
927 	 * the data normally if we cannot sufficiently compress it.
928 	 *
929 	 * We have a heuristic to detect files which are mostly
930 	 * uncompressable and avoid the compression attempt in that
931 	 * case.  If the compression heuristic is turned off, we always
932 	 * try to compress.
933 	 */
934 	comp_size = 0;
935 	comp_buffer = NULL;
936 
937 	KKASSERT(pblksize / 2 <= 32768);
938 
939 	if (ip->comp_heuristic < 8 || (ip->comp_heuristic & 7) == 0 ||
940 	    hammer2_always_compress) {
941 		z_stream strm_compress;
942 		int comp_level;
943 		int ret;
944 
945 		switch(HAMMER2_DEC_ALGO(comp_algo)) {
946 		case HAMMER2_COMP_LZ4:
947 			/*
948 			 * We need to prefix with the size, LZ4
949 			 * doesn't do it for us.  Add the related
950 			 * overhead.
951 			 *
952 			 * NOTE: The LZ4 code seems to assume at least an
953 			 *	 8-byte buffer size granularity and may
954 			 *	 overrun the buffer if given a 4-byte
955 			 *	 granularity.
956 			 */
957 			comp_buffer = ecalloc(1, 32768);
958 			comp_size = LZ4_compress_limitedOutput(
959 					data,
960 					&comp_buffer[sizeof(int)],
961 					pblksize,
962 					pblksize / 2 - sizeof(int64_t));
963 			*(int *)comp_buffer = comp_size;
964 			if (comp_size)
965 				comp_size += sizeof(int);
966 			break;
967 		case HAMMER2_COMP_ZLIB:
968 			comp_level = HAMMER2_DEC_LEVEL(comp_algo);
969 			if (comp_level == 0)
970 				comp_level = 6;	/* default zlib compression */
971 			else if (comp_level < 6)
972 				comp_level = 6;
973 			else if (comp_level > 9)
974 				comp_level = 9;
975 			ret = deflateInit(&strm_compress, comp_level);
976 			if (ret != Z_OK) {
977 				kprintf("HAMMER2 ZLIB: fatal error "
978 					"on deflateInit.\n");
979 			}
980 
981 			comp_buffer = ecalloc(1, 32768);
982 			strm_compress.next_in = data;
983 			strm_compress.avail_in = pblksize;
984 			strm_compress.next_out = comp_buffer;
985 			strm_compress.avail_out = pblksize / 2;
986 			ret = deflate(&strm_compress, Z_FINISH);
987 			if (ret == Z_STREAM_END) {
988 				comp_size = pblksize / 2 -
989 					    strm_compress.avail_out;
990 			} else {
991 				comp_size = 0;
992 			}
993 			ret = deflateEnd(&strm_compress);
994 			break;
995 		default:
996 			kprintf("Error: Unknown compression method.\n");
997 			kprintf("Comp_method = %d.\n", comp_algo);
998 			break;
999 		}
1000 	}
1001 
1002 	if (comp_size == 0) {
1003 		/*
1004 		 * compression failed or turned off
1005 		 */
1006 		comp_block_size = pblksize;	/* safety */
1007 		if (++ip->comp_heuristic > 128)
1008 			ip->comp_heuristic = 8;
1009 	} else {
1010 		/*
1011 		 * compression succeeded
1012 		 */
1013 		ip->comp_heuristic = 0;
1014 		if (comp_size <= 1024) {
1015 			comp_block_size = 1024;
1016 		} else if (comp_size <= 2048) {
1017 			comp_block_size = 2048;
1018 		} else if (comp_size <= 4096) {
1019 			comp_block_size = 4096;
1020 		} else if (comp_size <= 8192) {
1021 			comp_block_size = 8192;
1022 		} else if (comp_size <= 16384) {
1023 			comp_block_size = 16384;
1024 		} else if (comp_size <= 32768) {
1025 			comp_block_size = 32768;
1026 		} else {
1027 			panic("hammer2: WRITE PATH: "
1028 			      "Weird comp_size value.");
1029 			/* NOT REACHED */
1030 			comp_block_size = pblksize;
1031 		}
1032 
1033 		/*
1034 		 * Must zero the remainder or dedup (which operates on a
1035 		 * physical block basis) will not find matches.
1036 		 */
1037 		if (comp_size < comp_block_size) {
1038 			bzero(comp_buffer + comp_size,
1039 			      comp_block_size - comp_size);
1040 		}
1041 	}
1042 
1043 	/*
1044 	 * Assign physical storage, bdata will be set to NULL if a live-dedup
1045 	 * was successful.
1046 	 */
1047 	bdata = comp_size ? comp_buffer : data;
1048 	chain = hammer2_assign_physical(ip, parentp, lbase, comp_block_size,
1049 					mtid, &bdata, errorp);
1050 
1051 	if (*errorp) {
1052 		goto done;
1053 	}
1054 
1055 	if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
1056 		hammer2_inode_data_t *wipdata;
1057 
1058 		*errorp = hammer2_chain_modify_ip(ip, chain, mtid, 0);
1059 		if (*errorp == 0) {
1060 			wipdata = &chain->data->ipdata;
1061 			KKASSERT(wipdata->meta.op_flags &
1062 				 HAMMER2_OPFLAG_DIRECTDATA);
1063 			bcopy(data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1064 			++hammer2_iod_file_wembed;
1065 		}
1066 	} else if (bdata == NULL) {
1067 		/*
1068 		 * Live deduplication, a copy of the data is already present
1069 		 * on the media.
1070 		 */
1071 		if (comp_size) {
1072 			chain->bref.methods =
1073 				HAMMER2_ENC_COMP(comp_algo) +
1074 				HAMMER2_ENC_CHECK(check_algo);
1075 		} else {
1076 			chain->bref.methods =
1077 				HAMMER2_ENC_COMP(
1078 					HAMMER2_COMP_NONE) +
1079 				HAMMER2_ENC_CHECK(check_algo);
1080 		}
1081 		bdata = comp_size ? comp_buffer : data;
1082 		hammer2_chain_setcheck(chain, bdata);
1083 		atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1084 	} else {
1085 		hammer2_io_t *dio;
1086 
1087 		KKASSERT(chain->flags & HAMMER2_CHAIN_MODIFIED);
1088 
1089 		switch(chain->bref.type) {
1090 		case HAMMER2_BREF_TYPE_INODE:
1091 			panic("hammer2_compress_and_write: unexpected inode\n");
1092 			break;
1093 		case HAMMER2_BREF_TYPE_DATA:
1094 			/*
1095 			 * Optimize out the read-before-write
1096 			 * if possible.
1097 			 */
1098 			*errorp = hammer2_io_newnz(chain->hmp,
1099 						   chain->bref.type,
1100 						   chain->bref.data_off,
1101 						   chain->bytes,
1102 						   &dio);
1103 			if (*errorp) {
1104 				hammer2_io_brelse(&dio);
1105 				kprintf("hammer2: WRITE PATH: "
1106 					"dbp bread error\n");
1107 				break;
1108 			}
1109 			bdata = hammer2_io_data(dio, chain->bref.data_off);
1110 
1111 			/*
1112 			 * When loading the block make sure we don't
1113 			 * leave garbage after the compressed data.
1114 			 */
1115 			if (comp_size) {
1116 				chain->bref.methods =
1117 					HAMMER2_ENC_COMP(comp_algo) +
1118 					HAMMER2_ENC_CHECK(check_algo);
1119 				bcopy(comp_buffer, bdata, comp_block_size);
1120 			} else {
1121 				chain->bref.methods =
1122 					HAMMER2_ENC_COMP(
1123 						HAMMER2_COMP_NONE) +
1124 					HAMMER2_ENC_CHECK(check_algo);
1125 				bcopy(data, bdata, pblksize);
1126 			}
1127 
1128 			/*
1129 			 * The flush code doesn't calculate check codes for
1130 			 * file data (doing so can result in excessive I/O),
1131 			 * so we do it here.
1132 			 */
1133 			hammer2_chain_setcheck(chain, bdata);
1134 
1135 			/*
1136 			 * Device buffer is now valid, chain is no longer in
1137 			 * the initial state.
1138 			 *
1139 			 * (No blockref table worries with file data)
1140 			 */
1141 			atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1142 			hammer2_dedup_record(chain, dio, bdata);
1143 
1144 			/* Now write the related bdp. */
1145 			if (ioflag & IO_SYNC) {
1146 				/*
1147 				 * Synchronous I/O requested.
1148 				 */
1149 				hammer2_io_bwrite(&dio);
1150 			/*
1151 			} else if ((ioflag & IO_DIRECT) &&
1152 				   loff + n == pblksize) {
1153 				hammer2_io_bdwrite(&dio);
1154 			*/
1155 			} else if (ioflag & IO_ASYNC) {
1156 				hammer2_io_bawrite(&dio);
1157 			} else {
1158 				hammer2_io_bdwrite(&dio);
1159 			}
1160 			break;
1161 		default:
1162 			panic("hammer2_compress_and_write: bad chain type %d\n",
1163 				chain->bref.type);
1164 			/* NOT REACHED */
1165 			break;
1166 		}
1167 	}
1168 done:
1169 	if (chain) {
1170 		hammer2_chain_unlock(chain);
1171 		hammer2_chain_drop(chain);
1172 	}
1173 	if (comp_buffer)
1174 		free(comp_buffer);
1175 }
1176 
1177 /*
1178  * Helper
1179  *
1180  * Function that performs zero-checking and writing without compression,
1181  * it corresponds to default zero-checking path.
1182  */
1183 static
1184 void
1185 hammer2_zero_check_and_write(char *data, hammer2_inode_t *ip,
1186 	hammer2_chain_t **parentp,
1187 	hammer2_key_t lbase, int ioflag, int pblksize,
1188 	hammer2_tid_t mtid, int *errorp,
1189 	int check_algo)
1190 {
1191 	hammer2_chain_t *chain;
1192 	char *bdata;
1193 
1194 	if (check_algo != HAMMER2_CHECK_NONE &&
1195 	    test_block_zeros(data, pblksize)) {
1196 		/*
1197 		 * An all-zeros write creates a hole unless the check code
1198 		 * is disabled.  When the check code is disabled all writes
1199 		 * are done in-place, including any all-zeros writes.
1200 		 *
1201 		 * NOTE: A snapshot will still force a copy-on-write
1202 		 *	 (see the HAMMER2_CHECK_NONE in hammer2_chain.c).
1203 		 */
1204 		zero_write(data, ip, parentp, lbase, mtid, errorp);
1205 	} else {
1206 		/*
1207 		 * Normal write (bdata set to NULL if de-duplicated)
1208 		 */
1209 		bdata = data;
1210 		chain = hammer2_assign_physical(ip, parentp, lbase, pblksize,
1211 						mtid, &bdata, errorp);
1212 		if (*errorp) {
1213 			/* do nothing */
1214 		} else if (bdata) {
1215 			hammer2_write_bp(chain, data, ioflag, pblksize,
1216 					 mtid, errorp, check_algo);
1217 		} else {
1218 			/* dedup occurred */
1219 			chain->bref.methods =
1220 				HAMMER2_ENC_COMP(HAMMER2_COMP_NONE) +
1221 				HAMMER2_ENC_CHECK(check_algo);
1222 			hammer2_chain_setcheck(chain, data);
1223 			atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1224 		}
1225 		if (chain) {
1226 			hammer2_chain_unlock(chain);
1227 			hammer2_chain_drop(chain);
1228 		}
1229 	}
1230 }
1231 
1232 /*
1233  * Helper
1234  *
1235  * A function to test whether a block of data contains only zeros,
1236  * returns TRUE (non-zero) if the block is all zeros.
1237  */
1238 static
1239 int
1240 test_block_zeros(const char *buf, size_t bytes)
1241 {
1242 	size_t i;
1243 
1244 	for (i = 0; i < bytes; i += sizeof(long)) {
1245 		if (*(const long *)(buf + i) != 0)
1246 			return (0);
1247 	}
1248 	return (1);
1249 }
1250 
1251 /*
1252  * Helper
1253  *
1254  * Function to "write" a block that contains only zeros.
1255  */
1256 static
1257 void
1258 zero_write(char *data, hammer2_inode_t *ip,
1259 	   hammer2_chain_t **parentp,
1260 	   hammer2_key_t lbase, hammer2_tid_t mtid, int *errorp)
1261 {
1262 	hammer2_chain_t *chain;
1263 	hammer2_key_t key_dummy;
1264 
1265 	chain = hammer2_chain_lookup(parentp, &key_dummy,
1266 				     lbase, lbase,
1267 				     errorp,
1268 				     HAMMER2_LOOKUP_NODATA);
1269 	if (chain) {
1270 		if (chain->bref.type == HAMMER2_BREF_TYPE_INODE) {
1271 			hammer2_inode_data_t *wipdata;
1272 
1273 			if (*errorp == 0) {
1274 				*errorp = hammer2_chain_modify_ip(ip, chain,
1275 								  mtid, 0);
1276 			}
1277 			if (*errorp == 0) {
1278 				wipdata = &chain->data->ipdata;
1279 				KKASSERT(wipdata->meta.op_flags &
1280 					 HAMMER2_OPFLAG_DIRECTDATA);
1281 				bzero(wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1282 				++hammer2_iod_file_wembed;
1283 			}
1284 		} else {
1285 			/* chain->error ok for deletion */
1286 			hammer2_chain_delete(*parentp, chain,
1287 					     mtid, HAMMER2_DELETE_PERMANENT);
1288 			++hammer2_iod_file_wzero;
1289 		}
1290 		atomic_set_int(&ip->flags, HAMMER2_INODE_DIRTYDATA);
1291 		hammer2_chain_unlock(chain);
1292 		hammer2_chain_drop(chain);
1293 	} else {
1294 		++hammer2_iod_file_wzero;
1295 	}
1296 }
1297 
1298 /*
1299  * Helper
1300  *
1301  * Function to write the data as it is, without performing any sort of
1302  * compression. This function is used in path without compression and
1303  * default zero-checking path.
1304  */
1305 static
1306 void
1307 hammer2_write_bp(hammer2_chain_t *chain, char *data, int ioflag,
1308 		 int pblksize,
1309 		 hammer2_tid_t mtid, int *errorp, int check_algo)
1310 {
1311 	hammer2_inode_data_t *wipdata;
1312 	hammer2_io_t *dio;
1313 	char *bdata;
1314 	int error;
1315 
1316 	error = 0;	/* XXX TODO below */
1317 
1318 	KKASSERT(chain->flags & HAMMER2_CHAIN_MODIFIED);
1319 
1320 	switch(chain->bref.type) {
1321 	case HAMMER2_BREF_TYPE_INODE:
1322 		wipdata = &chain->data->ipdata;
1323 		KKASSERT(wipdata->meta.op_flags & HAMMER2_OPFLAG_DIRECTDATA);
1324 		bcopy(data, wipdata->u.data, HAMMER2_EMBEDDED_BYTES);
1325 		error = 0;
1326 		++hammer2_iod_file_wembed;
1327 		break;
1328 	case HAMMER2_BREF_TYPE_DATA:
1329 		error = hammer2_io_newnz(chain->hmp,
1330 					 chain->bref.type,
1331 					 chain->bref.data_off,
1332 					 chain->bytes, &dio);
1333 		if (error) {
1334 			hammer2_io_bqrelse(&dio);
1335 			kprintf("hammer2: WRITE PATH: "
1336 				"dbp bread error\n");
1337 			break;
1338 		}
1339 		bdata = hammer2_io_data(dio, chain->bref.data_off);
1340 
1341 		chain->bref.methods = HAMMER2_ENC_COMP(HAMMER2_COMP_NONE) +
1342 				      HAMMER2_ENC_CHECK(check_algo);
1343 		bcopy(data, bdata, chain->bytes);
1344 
1345 		/*
1346 		 * The flush code doesn't calculate check codes for
1347 		 * file data (doing so can result in excessive I/O),
1348 		 * so we do it here.
1349 		 */
1350 		hammer2_chain_setcheck(chain, bdata);
1351 
1352 		/*
1353 		 * Device buffer is now valid, chain is no longer in
1354 		 * the initial state.
1355 		 *
1356 		 * (No blockref table worries with file data)
1357 		 */
1358 		atomic_clear_int(&chain->flags, HAMMER2_CHAIN_INITIAL);
1359 		hammer2_dedup_record(chain, dio, bdata);
1360 
1361 		if (ioflag & IO_SYNC) {
1362 			/*
1363 			 * Synchronous I/O requested.
1364 			 */
1365 			hammer2_io_bwrite(&dio);
1366 		/*
1367 		} else if ((ioflag & IO_DIRECT) &&
1368 			   loff + n == pblksize) {
1369 			hammer2_io_bdwrite(&dio);
1370 		*/
1371 		} else if (ioflag & IO_ASYNC) {
1372 			hammer2_io_bawrite(&dio);
1373 		} else {
1374 			hammer2_io_bdwrite(&dio);
1375 		}
1376 		break;
1377 	default:
1378 		panic("hammer2_write_bp: bad chain type %d\n",
1379 		      chain->bref.type);
1380 		/* NOT REACHED */
1381 		error = 0;
1382 		break;
1383 	}
1384 	*errorp = error;
1385 }
1386 
1387 /*
1388  * LIVE DEDUP HEURISTICS
1389  *
1390  * Record media and crc information for possible dedup operation.  Note
1391  * that the dedup mask bits must also be set in the related DIO for a dedup
1392  * to be fully validated (which is handled in the freemap allocation code).
1393  *
1394  * WARNING! This code is SMP safe but the heuristic allows SMP collisions.
1395  *	    All fields must be loaded into locals and validated.
1396  *
1397  * WARNING! Should only be used for file data and directory entries,
1398  *	    hammer2_chain_modify() only checks for the dedup case on data
1399  *	    chains.  Also, dedup data can only be recorded for committed
1400  *	    chains (so NOT strategy writes which can undergo further
1401  *	    modification after the fact!).
1402  */
1403 void
1404 hammer2_dedup_record(hammer2_chain_t *chain, hammer2_io_t *dio,
1405 		     const char *data)
1406 {
1407 	hammer2_dev_t *hmp;
1408 	hammer2_dedup_t *dedup;
1409 	uint64_t crc;
1410 	uint64_t mask;
1411 	int best = 0;
1412 	int i;
1413 	int dticks;
1414 
1415 	/*
1416 	 * We can only record a dedup if we have media data to test against.
1417 	 * If dedup is not enabled, return early, which allows a chain to
1418 	 * remain marked MODIFIED (which might have benefits in special
1419 	 * situations, though typically it does not).
1420 	 */
1421 	if (hammer2_dedup_enable == 0)
1422 		return;
1423 	if (dio == NULL) {
1424 		dio = chain->dio;
1425 		if (dio == NULL)
1426 			return;
1427 	}
1428 
1429 	hmp = chain->hmp;
1430 
1431 	switch(HAMMER2_DEC_CHECK(chain->bref.methods)) {
1432 	case HAMMER2_CHECK_ISCSI32:
1433 		/*
1434 		 * XXX use the built-in crc (the dedup lookup sequencing
1435 		 * needs to be fixed so the check code is already present
1436 		 * when dedup_lookup is called)
1437 		 */
1438 #if 0
1439 		crc = (uint64_t)(uint32_t)chain->bref.check.iscsi32.value;
1440 #endif
1441 		crc = XXH64(data, chain->bytes, XXH_HAMMER2_SEED);
1442 		break;
1443 	case HAMMER2_CHECK_XXHASH64:
1444 		crc = chain->bref.check.xxhash64.value;
1445 		break;
1446 	case HAMMER2_CHECK_SHA192:
1447 		/*
1448 		 * XXX use the built-in crc (the dedup lookup sequencing
1449 		 * needs to be fixed so the check code is already present
1450 		 * when dedup_lookup is called)
1451 		 */
1452 #if 0
1453 		crc = ((uint64_t *)chain->bref.check.sha192.data)[0] ^
1454 		      ((uint64_t *)chain->bref.check.sha192.data)[1] ^
1455 		      ((uint64_t *)chain->bref.check.sha192.data)[2];
1456 #endif
1457 		crc = XXH64(data, chain->bytes, XXH_HAMMER2_SEED);
1458 		break;
1459 	default:
1460 		/*
1461 		 * Cannot dedup without a check code
1462 		 *
1463 		 * NOTE: In particular, CHECK_NONE allows a sector to be
1464 		 *	 overwritten without copy-on-write, recording
1465 		 *	 a dedup block for a CHECK_NONE object would be
1466 		 *	 a disaster!
1467 		 */
1468 		return;
1469 	}
1470 
1471 	atomic_set_int(&chain->flags, HAMMER2_CHAIN_DEDUPABLE);
1472 
1473 	dedup = &hmp->heur_dedup[crc & (HAMMER2_DEDUP_HEUR_MASK & ~3)];
1474 	for (i = 0; i < 4; ++i) {
1475 		if (dedup[i].data_crc == crc) {
1476 			best = i;
1477 			break;
1478 		}
1479 		dticks = (int)(dedup[i].ticks - dedup[best].ticks);
1480 		if (dticks < 0 || dticks > hz * 60 * 30)
1481 			best = i;
1482 	}
1483 	dedup += best;
1484 	if (hammer2_debug & 0x40000) {
1485 		kprintf("REC %04x %016jx %016jx\n",
1486 			(int)(dedup - hmp->heur_dedup),
1487 			crc,
1488 			chain->bref.data_off);
1489 	}
1490 	dedup->ticks = ticks;
1491 	dedup->data_off = chain->bref.data_off;
1492 	dedup->data_crc = crc;
1493 
1494 	/*
1495 	 * Set the valid bits for the dedup only after we know the data
1496 	 * buffer has been updated.  The alloc bits were set (and the valid
1497 	 * bits cleared) when the media was allocated.
1498 	 *
1499 	 * This is done in two stages becuase the bulkfree code can race
1500 	 * the gap between allocation and data population.  Both masks must
1501 	 * be set before a bcmp/dedup operation is able to use the block.
1502 	 */
1503 	mask = hammer2_dedup_mask(dio, chain->bref.data_off, chain->bytes);
1504 	atomic_set_64(&dio->dedup_valid, mask);
1505 
1506 #if 0
1507 	/*
1508 	 * XXX removed. MODIFIED is an integral part of the flush code,
1509 	 * lets not just clear it
1510 	 */
1511 	/*
1512 	 * Once we record the dedup the chain must be marked clean to
1513 	 * prevent reuse of the underlying block.   Remember that this
1514 	 * write occurs when the buffer cache is flushed (i.e. on sync(),
1515 	 * fsync(), filesystem periodic sync, or when the kernel needs to
1516 	 * flush a buffer), and not whenever the user write()s.
1517 	 */
1518 	if (chain->flags & HAMMER2_CHAIN_MODIFIED) {
1519 		atomic_clear_int(&chain->flags, HAMMER2_CHAIN_MODIFIED);
1520 		atomic_add_long(&hammer2_count_modified_chains, -1);
1521 		if (chain->pmp)
1522 			hammer2_pfs_memory_wakeup(chain->pmp, -1);
1523 	}
1524 #endif
1525 }
1526 
1527 static
1528 hammer2_off_t
1529 hammer2_dedup_lookup(hammer2_dev_t *hmp, char **datap, int pblksize)
1530 {
1531 	hammer2_dedup_t *dedup;
1532 	hammer2_io_t *dio;
1533 	hammer2_off_t off;
1534 	uint64_t crc;
1535 	uint64_t mask;
1536 	char *data;
1537 	char *dtmp;
1538 	int i;
1539 
1540 	if (hammer2_dedup_enable == 0)
1541 		return 0;
1542 	data = *datap;
1543 	if (data == NULL)
1544 		return 0;
1545 
1546 	/*
1547 	 * XXX use the built-in crc (the dedup lookup sequencing
1548 	 * needs to be fixed so the check code is already present
1549 	 * when dedup_lookup is called)
1550 	 */
1551 	crc = XXH64(data, pblksize, XXH_HAMMER2_SEED);
1552 	dedup = &hmp->heur_dedup[crc & (HAMMER2_DEDUP_HEUR_MASK & ~3)];
1553 
1554 	if (hammer2_debug & 0x40000) {
1555 		kprintf("LOC %04x/4 %016jx\n",
1556 			(int)(dedup - hmp->heur_dedup),
1557 			crc);
1558 	}
1559 
1560 	for (i = 0; i < 4; ++i) {
1561 		off = dedup[i].data_off;
1562 		cpu_ccfence();
1563 		if (dedup[i].data_crc != crc)
1564 			continue;
1565 		if ((1 << (int)(off & HAMMER2_OFF_MASK_RADIX)) != pblksize)
1566 			continue;
1567 		dio = hammer2_io_getquick(hmp, off, pblksize);
1568 		if (dio) {
1569 			dtmp = hammer2_io_data(dio, off),
1570 			mask = hammer2_dedup_mask(dio, off, pblksize);
1571 			if ((dio->dedup_alloc & mask) == mask &&
1572 			    (dio->dedup_valid & mask) == mask &&
1573 			    bcmp(data, dtmp, pblksize) == 0) {
1574 				if (hammer2_debug & 0x40000) {
1575 					kprintf("DEDUP SUCCESS %016jx\n",
1576 						(intmax_t)off);
1577 				}
1578 				hammer2_io_putblk(&dio);
1579 				*datap = NULL;
1580 				dedup[i].ticks = ticks;   /* update use */
1581 				atomic_add_long(&hammer2_iod_file_wdedup,
1582 						pblksize);
1583 
1584 				return off;		/* RETURN */
1585 			}
1586 			hammer2_io_putblk(&dio);
1587 		}
1588 	}
1589 	return 0;
1590 }
1591 
1592 /*
1593  * Poof.  Races are ok, if someone gets in and reuses a dedup offset
1594  * before or while we are clearing it they will also recover the freemap
1595  * entry (set it to fully allocated), so a bulkfree race can only set it
1596  * to a possibly-free state.
1597  *
1598  * XXX ok, well, not really sure races are ok but going to run with it
1599  *     for the moment.
1600  */
1601 void
1602 hammer2_dedup_clear(hammer2_dev_t *hmp)
1603 {
1604 	int i;
1605 
1606 	for (i = 0; i < HAMMER2_DEDUP_HEUR_SIZE; ++i) {
1607 		hmp->heur_dedup[i].data_off = 0;
1608 		hmp->heur_dedup[i].ticks = ticks - 1;
1609 	}
1610 }
1611