xref: /titanic_52/usr/src/uts/common/fs/zfs/dmu.c (revision 0bb073995ac5a95bd35f2dd790df1ea3d8c2d507)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #include <sys/dmu.h>
27 #include <sys/dmu_impl.h>
28 #include <sys/dmu_tx.h>
29 #include <sys/dbuf.h>
30 #include <sys/dnode.h>
31 #include <sys/zfs_context.h>
32 #include <sys/dmu_objset.h>
33 #include <sys/dmu_traverse.h>
34 #include <sys/dsl_dataset.h>
35 #include <sys/dsl_dir.h>
36 #include <sys/dsl_pool.h>
37 #include <sys/dsl_synctask.h>
38 #include <sys/dsl_prop.h>
39 #include <sys/dmu_zfetch.h>
40 #include <sys/zfs_ioctl.h>
41 #include <sys/zap.h>
42 #include <sys/zio_checksum.h>
43 #ifdef _KERNEL
44 #include <sys/vmsystm.h>
45 #include <sys/zfs_znode.h>
46 #endif
47 
48 const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES] = {
49 	{	byteswap_uint8_array,	TRUE,	"unallocated"		},
50 	{	zap_byteswap,		TRUE,	"object directory"	},
51 	{	byteswap_uint64_array,	TRUE,	"object array"		},
52 	{	byteswap_uint8_array,	TRUE,	"packed nvlist"		},
53 	{	byteswap_uint64_array,	TRUE,	"packed nvlist size"	},
54 	{	byteswap_uint64_array,	TRUE,	"bplist"		},
55 	{	byteswap_uint64_array,	TRUE,	"bplist header"		},
56 	{	byteswap_uint64_array,	TRUE,	"SPA space map header"	},
57 	{	byteswap_uint64_array,	TRUE,	"SPA space map"		},
58 	{	byteswap_uint64_array,	TRUE,	"ZIL intent log"	},
59 	{	dnode_buf_byteswap,	TRUE,	"DMU dnode"		},
60 	{	dmu_objset_byteswap,	TRUE,	"DMU objset"		},
61 	{	byteswap_uint64_array,	TRUE,	"DSL directory"		},
62 	{	zap_byteswap,		TRUE,	"DSL directory child map"},
63 	{	zap_byteswap,		TRUE,	"DSL dataset snap map"	},
64 	{	zap_byteswap,		TRUE,	"DSL props"		},
65 	{	byteswap_uint64_array,	TRUE,	"DSL dataset"		},
66 	{	zfs_znode_byteswap,	TRUE,	"ZFS znode"		},
67 	{	zfs_oldacl_byteswap,	TRUE,	"ZFS V0 ACL"		},
68 	{	byteswap_uint8_array,	FALSE,	"ZFS plain file"	},
69 	{	zap_byteswap,		TRUE,	"ZFS directory"		},
70 	{	zap_byteswap,		TRUE,	"ZFS master node"	},
71 	{	zap_byteswap,		TRUE,	"ZFS delete queue"	},
72 	{	byteswap_uint8_array,	FALSE,	"zvol object"		},
73 	{	zap_byteswap,		TRUE,	"zvol prop"		},
74 	{	byteswap_uint8_array,	FALSE,	"other uint8[]"		},
75 	{	byteswap_uint64_array,	FALSE,	"other uint64[]"	},
76 	{	zap_byteswap,		TRUE,	"other ZAP"		},
77 	{	zap_byteswap,		TRUE,	"persistent error log"	},
78 	{	byteswap_uint8_array,	TRUE,	"SPA history"		},
79 	{	byteswap_uint64_array,	TRUE,	"SPA history offsets"	},
80 	{	zap_byteswap,		TRUE,	"Pool properties"	},
81 	{	zap_byteswap,		TRUE,	"DSL permissions"	},
82 	{	zfs_acl_byteswap,	TRUE,	"ZFS ACL"		},
83 	{	byteswap_uint8_array,	TRUE,	"ZFS SYSACL"		},
84 	{	byteswap_uint8_array,	TRUE,	"FUID table"		},
85 	{	byteswap_uint64_array,	TRUE,	"FUID table size"	},
86 	{	zap_byteswap,		TRUE,	"DSL dataset next clones"},
87 	{	zap_byteswap,		TRUE,	"scrub work queue"	},
88 };
89 
90 int
91 dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
92     void *tag, dmu_buf_t **dbp)
93 {
94 	dnode_t *dn;
95 	uint64_t blkid;
96 	dmu_buf_impl_t *db;
97 	int err;
98 
99 	err = dnode_hold(os->os, object, FTAG, &dn);
100 	if (err)
101 		return (err);
102 	blkid = dbuf_whichblock(dn, offset);
103 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
104 	db = dbuf_hold(dn, blkid, tag);
105 	rw_exit(&dn->dn_struct_rwlock);
106 	if (db == NULL) {
107 		err = EIO;
108 	} else {
109 		err = dbuf_read(db, NULL, DB_RF_CANFAIL);
110 		if (err) {
111 			dbuf_rele(db, tag);
112 			db = NULL;
113 		}
114 	}
115 
116 	dnode_rele(dn, FTAG);
117 	*dbp = &db->db;
118 	return (err);
119 }
120 
121 int
122 dmu_bonus_max(void)
123 {
124 	return (DN_MAX_BONUSLEN);
125 }
126 
127 int
128 dmu_set_bonus(dmu_buf_t *db, int newsize, dmu_tx_t *tx)
129 {
130 	dnode_t *dn = ((dmu_buf_impl_t *)db)->db_dnode;
131 
132 	if (dn->dn_bonus != (dmu_buf_impl_t *)db)
133 		return (EINVAL);
134 	if (newsize < 0 || newsize > db->db_size)
135 		return (EINVAL);
136 	dnode_setbonuslen(dn, newsize, tx);
137 	return (0);
138 }
139 
140 /*
141  * returns ENOENT, EIO, or 0.
142  */
143 int
144 dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **dbp)
145 {
146 	dnode_t *dn;
147 	dmu_buf_impl_t *db;
148 	int error;
149 
150 	error = dnode_hold(os->os, object, FTAG, &dn);
151 	if (error)
152 		return (error);
153 
154 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
155 	if (dn->dn_bonus == NULL) {
156 		rw_exit(&dn->dn_struct_rwlock);
157 		rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
158 		if (dn->dn_bonus == NULL)
159 			dbuf_create_bonus(dn);
160 	}
161 	db = dn->dn_bonus;
162 	rw_exit(&dn->dn_struct_rwlock);
163 
164 	/* as long as the bonus buf is held, the dnode will be held */
165 	if (refcount_add(&db->db_holds, tag) == 1)
166 		VERIFY(dnode_add_ref(dn, db));
167 
168 	dnode_rele(dn, FTAG);
169 
170 	VERIFY(0 == dbuf_read(db, NULL, DB_RF_MUST_SUCCEED));
171 
172 	*dbp = &db->db;
173 	return (0);
174 }
175 
176 /*
177  * Note: longer-term, we should modify all of the dmu_buf_*() interfaces
178  * to take a held dnode rather than <os, object> -- the lookup is wasteful,
179  * and can induce severe lock contention when writing to several files
180  * whose dnodes are in the same block.
181  */
182 static int
183 dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset,
184     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp)
185 {
186 	dsl_pool_t *dp = NULL;
187 	dmu_buf_t **dbp;
188 	uint64_t blkid, nblks, i;
189 	uint32_t flags;
190 	int err;
191 	zio_t *zio;
192 	hrtime_t start;
193 
194 	ASSERT(length <= DMU_MAX_ACCESS);
195 
196 	flags = DB_RF_CANFAIL | DB_RF_NEVERWAIT;
197 	if (length > zfetch_array_rd_sz)
198 		flags |= DB_RF_NOPREFETCH;
199 
200 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
201 	if (dn->dn_datablkshift) {
202 		int blkshift = dn->dn_datablkshift;
203 		nblks = (P2ROUNDUP(offset+length, 1ULL<<blkshift) -
204 		    P2ALIGN(offset, 1ULL<<blkshift)) >> blkshift;
205 	} else {
206 		if (offset + length > dn->dn_datablksz) {
207 			zfs_panic_recover("zfs: accessing past end of object "
208 			    "%llx/%llx (size=%u access=%llu+%llu)",
209 			    (longlong_t)dn->dn_objset->
210 			    os_dsl_dataset->ds_object,
211 			    (longlong_t)dn->dn_object, dn->dn_datablksz,
212 			    (longlong_t)offset, (longlong_t)length);
213 			return (EIO);
214 		}
215 		nblks = 1;
216 	}
217 	dbp = kmem_zalloc(sizeof (dmu_buf_t *) * nblks, KM_SLEEP);
218 
219 	if (dn->dn_objset->os_dsl_dataset)
220 		dp = dn->dn_objset->os_dsl_dataset->ds_dir->dd_pool;
221 	if (dp && dsl_pool_sync_context(dp))
222 		start = gethrtime();
223 	zio = zio_root(dn->dn_objset->os_spa, NULL, NULL, TRUE);
224 	blkid = dbuf_whichblock(dn, offset);
225 	for (i = 0; i < nblks; i++) {
226 		dmu_buf_impl_t *db = dbuf_hold(dn, blkid+i, tag);
227 		if (db == NULL) {
228 			rw_exit(&dn->dn_struct_rwlock);
229 			dmu_buf_rele_array(dbp, nblks, tag);
230 			zio_nowait(zio);
231 			return (EIO);
232 		}
233 		/* initiate async i/o */
234 		if (read) {
235 			rw_exit(&dn->dn_struct_rwlock);
236 			(void) dbuf_read(db, zio, flags);
237 			rw_enter(&dn->dn_struct_rwlock, RW_READER);
238 		}
239 		dbp[i] = &db->db;
240 	}
241 	rw_exit(&dn->dn_struct_rwlock);
242 
243 	/* wait for async i/o */
244 	err = zio_wait(zio);
245 	/* track read overhead when we are in sync context */
246 	if (dp && dsl_pool_sync_context(dp))
247 		dp->dp_read_overhead += gethrtime() - start;
248 	if (err) {
249 		dmu_buf_rele_array(dbp, nblks, tag);
250 		return (err);
251 	}
252 
253 	/* wait for other io to complete */
254 	if (read) {
255 		for (i = 0; i < nblks; i++) {
256 			dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbp[i];
257 			mutex_enter(&db->db_mtx);
258 			while (db->db_state == DB_READ ||
259 			    db->db_state == DB_FILL)
260 				cv_wait(&db->db_changed, &db->db_mtx);
261 			if (db->db_state == DB_UNCACHED)
262 				err = EIO;
263 			mutex_exit(&db->db_mtx);
264 			if (err) {
265 				dmu_buf_rele_array(dbp, nblks, tag);
266 				return (err);
267 			}
268 		}
269 	}
270 
271 	*numbufsp = nblks;
272 	*dbpp = dbp;
273 	return (0);
274 }
275 
276 static int
277 dmu_buf_hold_array(objset_t *os, uint64_t object, uint64_t offset,
278     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp)
279 {
280 	dnode_t *dn;
281 	int err;
282 
283 	err = dnode_hold(os->os, object, FTAG, &dn);
284 	if (err)
285 		return (err);
286 
287 	err = dmu_buf_hold_array_by_dnode(dn, offset, length, read, tag,
288 	    numbufsp, dbpp);
289 
290 	dnode_rele(dn, FTAG);
291 
292 	return (err);
293 }
294 
295 int
296 dmu_buf_hold_array_by_bonus(dmu_buf_t *db, uint64_t offset,
297     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp)
298 {
299 	dnode_t *dn = ((dmu_buf_impl_t *)db)->db_dnode;
300 	int err;
301 
302 	err = dmu_buf_hold_array_by_dnode(dn, offset, length, read, tag,
303 	    numbufsp, dbpp);
304 
305 	return (err);
306 }
307 
308 void
309 dmu_buf_rele_array(dmu_buf_t **dbp_fake, int numbufs, void *tag)
310 {
311 	int i;
312 	dmu_buf_impl_t **dbp = (dmu_buf_impl_t **)dbp_fake;
313 
314 	if (numbufs == 0)
315 		return;
316 
317 	for (i = 0; i < numbufs; i++) {
318 		if (dbp[i])
319 			dbuf_rele(dbp[i], tag);
320 	}
321 
322 	kmem_free(dbp, sizeof (dmu_buf_t *) * numbufs);
323 }
324 
325 void
326 dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset, uint64_t len)
327 {
328 	dnode_t *dn;
329 	uint64_t blkid;
330 	int nblks, i, err;
331 
332 	if (zfs_prefetch_disable)
333 		return;
334 
335 	if (len == 0) {  /* they're interested in the bonus buffer */
336 		dn = os->os->os_meta_dnode;
337 
338 		if (object == 0 || object >= DN_MAX_OBJECT)
339 			return;
340 
341 		rw_enter(&dn->dn_struct_rwlock, RW_READER);
342 		blkid = dbuf_whichblock(dn, object * sizeof (dnode_phys_t));
343 		dbuf_prefetch(dn, blkid);
344 		rw_exit(&dn->dn_struct_rwlock);
345 		return;
346 	}
347 
348 	/*
349 	 * XXX - Note, if the dnode for the requested object is not
350 	 * already cached, we will do a *synchronous* read in the
351 	 * dnode_hold() call.  The same is true for any indirects.
352 	 */
353 	err = dnode_hold(os->os, object, FTAG, &dn);
354 	if (err != 0)
355 		return;
356 
357 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
358 	if (dn->dn_datablkshift) {
359 		int blkshift = dn->dn_datablkshift;
360 		nblks = (P2ROUNDUP(offset+len, 1<<blkshift) -
361 		    P2ALIGN(offset, 1<<blkshift)) >> blkshift;
362 	} else {
363 		nblks = (offset < dn->dn_datablksz);
364 	}
365 
366 	if (nblks != 0) {
367 		blkid = dbuf_whichblock(dn, offset);
368 		for (i = 0; i < nblks; i++)
369 			dbuf_prefetch(dn, blkid+i);
370 	}
371 
372 	rw_exit(&dn->dn_struct_rwlock);
373 
374 	dnode_rele(dn, FTAG);
375 }
376 
377 static int
378 get_next_chunk(dnode_t *dn, uint64_t *offset, uint64_t limit)
379 {
380 	uint64_t len = *offset - limit;
381 	uint64_t chunk_len = dn->dn_datablksz * DMU_MAX_DELETEBLKCNT;
382 	uint64_t subchunk =
383 	    dn->dn_datablksz * EPB(dn->dn_indblkshift, SPA_BLKPTRSHIFT);
384 
385 	ASSERT(limit <= *offset);
386 
387 	if (len <= chunk_len) {
388 		*offset = limit;
389 		return (0);
390 	}
391 
392 	ASSERT(ISP2(subchunk));
393 
394 	while (*offset > limit) {
395 		uint64_t initial_offset = P2ROUNDUP(*offset, subchunk);
396 		uint64_t delta;
397 		int err;
398 
399 		/* skip over allocated data */
400 		err = dnode_next_offset(dn,
401 		    DNODE_FIND_HOLE|DNODE_FIND_BACKWARDS, offset, 1, 1, 0);
402 		if (err == ESRCH)
403 			*offset = limit;
404 		else if (err)
405 			return (err);
406 
407 		ASSERT3U(*offset, <=, initial_offset);
408 		*offset = P2ALIGN(*offset, subchunk);
409 		delta = initial_offset - *offset;
410 		if (delta >= chunk_len) {
411 			*offset += delta - chunk_len;
412 			return (0);
413 		}
414 		chunk_len -= delta;
415 
416 		/* skip over unallocated data */
417 		err = dnode_next_offset(dn,
418 		    DNODE_FIND_BACKWARDS, offset, 1, 1, 0);
419 		if (err == ESRCH)
420 			*offset = limit;
421 		else if (err)
422 			return (err);
423 
424 		if (*offset < limit)
425 			*offset = limit;
426 		ASSERT3U(*offset, <, initial_offset);
427 	}
428 	return (0);
429 }
430 
431 static int
432 dmu_free_long_range_impl(objset_t *os, dnode_t *dn, uint64_t offset,
433     uint64_t length, boolean_t free_dnode)
434 {
435 	dmu_tx_t *tx;
436 	uint64_t object_size, start, end, len;
437 	boolean_t trunc = (length == DMU_OBJECT_END);
438 	int align, err;
439 
440 	align = 1 << dn->dn_datablkshift;
441 	ASSERT(align > 0);
442 	object_size = align == 1 ? dn->dn_datablksz :
443 	    (dn->dn_maxblkid + 1) << dn->dn_datablkshift;
444 
445 	if (trunc || (end = offset + length) > object_size)
446 		end = object_size;
447 	if (end <= offset)
448 		return (0);
449 	length = end - offset;
450 
451 	while (length) {
452 		start = end;
453 		err = get_next_chunk(dn, &start, offset);
454 		if (err)
455 			return (err);
456 		len = trunc ? DMU_OBJECT_END : end - start;
457 
458 		tx = dmu_tx_create(os);
459 		dmu_tx_hold_free(tx, dn->dn_object, start, len);
460 		err = dmu_tx_assign(tx, TXG_WAIT);
461 		if (err) {
462 			dmu_tx_abort(tx);
463 			return (err);
464 		}
465 
466 		dnode_free_range(dn, start, trunc ? -1 : len, tx);
467 
468 		if (start == 0 && free_dnode) {
469 			ASSERT(trunc);
470 			dnode_free(dn, tx);
471 		}
472 
473 		length -= end - start;
474 
475 		dmu_tx_commit(tx);
476 		end = start;
477 	}
478 	return (0);
479 }
480 
481 int
482 dmu_free_long_range(objset_t *os, uint64_t object,
483     uint64_t offset, uint64_t length)
484 {
485 	dnode_t *dn;
486 	int err;
487 
488 	err = dnode_hold(os->os, object, FTAG, &dn);
489 	if (err != 0)
490 		return (err);
491 	err = dmu_free_long_range_impl(os, dn, offset, length, FALSE);
492 	dnode_rele(dn, FTAG);
493 	return (err);
494 }
495 
496 int
497 dmu_free_object(objset_t *os, uint64_t object)
498 {
499 	dnode_t *dn;
500 	dmu_tx_t *tx;
501 	int err;
502 
503 	err = dnode_hold_impl(os->os, object, DNODE_MUST_BE_ALLOCATED,
504 	    FTAG, &dn);
505 	if (err != 0)
506 		return (err);
507 	if (dn->dn_nlevels == 1) {
508 		tx = dmu_tx_create(os);
509 		dmu_tx_hold_bonus(tx, object);
510 		dmu_tx_hold_free(tx, dn->dn_object, 0, DMU_OBJECT_END);
511 		err = dmu_tx_assign(tx, TXG_WAIT);
512 		if (err == 0) {
513 			dnode_free_range(dn, 0, DMU_OBJECT_END, tx);
514 			dnode_free(dn, tx);
515 			dmu_tx_commit(tx);
516 		} else {
517 			dmu_tx_abort(tx);
518 		}
519 	} else {
520 		err = dmu_free_long_range_impl(os, dn, 0, DMU_OBJECT_END, TRUE);
521 	}
522 	dnode_rele(dn, FTAG);
523 	return (err);
524 }
525 
526 int
527 dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
528     uint64_t size, dmu_tx_t *tx)
529 {
530 	dnode_t *dn;
531 	int err = dnode_hold(os->os, object, FTAG, &dn);
532 	if (err)
533 		return (err);
534 	ASSERT(offset < UINT64_MAX);
535 	ASSERT(size == -1ULL || size <= UINT64_MAX - offset);
536 	dnode_free_range(dn, offset, size, tx);
537 	dnode_rele(dn, FTAG);
538 	return (0);
539 }
540 
541 int
542 dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
543     void *buf)
544 {
545 	dnode_t *dn;
546 	dmu_buf_t **dbp;
547 	int numbufs, i, err;
548 
549 	err = dnode_hold(os->os, object, FTAG, &dn);
550 	if (err)
551 		return (err);
552 
553 	/*
554 	 * Deal with odd block sizes, where there can't be data past the first
555 	 * block.  If we ever do the tail block optimization, we will need to
556 	 * handle that here as well.
557 	 */
558 	if (dn->dn_datablkshift == 0) {
559 		int newsz = offset > dn->dn_datablksz ? 0 :
560 		    MIN(size, dn->dn_datablksz - offset);
561 		bzero((char *)buf + newsz, size - newsz);
562 		size = newsz;
563 	}
564 
565 	while (size > 0) {
566 		uint64_t mylen = MIN(size, DMU_MAX_ACCESS / 2);
567 
568 		/*
569 		 * NB: we could do this block-at-a-time, but it's nice
570 		 * to be reading in parallel.
571 		 */
572 		err = dmu_buf_hold_array_by_dnode(dn, offset, mylen,
573 		    TRUE, FTAG, &numbufs, &dbp);
574 		if (err)
575 			break;
576 
577 		for (i = 0; i < numbufs; i++) {
578 			int tocpy;
579 			int bufoff;
580 			dmu_buf_t *db = dbp[i];
581 
582 			ASSERT(size > 0);
583 
584 			bufoff = offset - db->db_offset;
585 			tocpy = (int)MIN(db->db_size - bufoff, size);
586 
587 			bcopy((char *)db->db_data + bufoff, buf, tocpy);
588 
589 			offset += tocpy;
590 			size -= tocpy;
591 			buf = (char *)buf + tocpy;
592 		}
593 		dmu_buf_rele_array(dbp, numbufs, FTAG);
594 	}
595 	dnode_rele(dn, FTAG);
596 	return (err);
597 }
598 
599 void
600 dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
601     const void *buf, dmu_tx_t *tx)
602 {
603 	dmu_buf_t **dbp;
604 	int numbufs, i;
605 
606 	if (size == 0)
607 		return;
608 
609 	VERIFY(0 == dmu_buf_hold_array(os, object, offset, size,
610 	    FALSE, FTAG, &numbufs, &dbp));
611 
612 	for (i = 0; i < numbufs; i++) {
613 		int tocpy;
614 		int bufoff;
615 		dmu_buf_t *db = dbp[i];
616 
617 		ASSERT(size > 0);
618 
619 		bufoff = offset - db->db_offset;
620 		tocpy = (int)MIN(db->db_size - bufoff, size);
621 
622 		ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
623 
624 		if (tocpy == db->db_size)
625 			dmu_buf_will_fill(db, tx);
626 		else
627 			dmu_buf_will_dirty(db, tx);
628 
629 		bcopy(buf, (char *)db->db_data + bufoff, tocpy);
630 
631 		if (tocpy == db->db_size)
632 			dmu_buf_fill_done(db, tx);
633 
634 		offset += tocpy;
635 		size -= tocpy;
636 		buf = (char *)buf + tocpy;
637 	}
638 	dmu_buf_rele_array(dbp, numbufs, FTAG);
639 }
640 
641 #ifdef _KERNEL
642 int
643 dmu_read_uio(objset_t *os, uint64_t object, uio_t *uio, uint64_t size)
644 {
645 	dmu_buf_t **dbp;
646 	int numbufs, i, err;
647 
648 	/*
649 	 * NB: we could do this block-at-a-time, but it's nice
650 	 * to be reading in parallel.
651 	 */
652 	err = dmu_buf_hold_array(os, object, uio->uio_loffset, size, TRUE, FTAG,
653 	    &numbufs, &dbp);
654 	if (err)
655 		return (err);
656 
657 	for (i = 0; i < numbufs; i++) {
658 		int tocpy;
659 		int bufoff;
660 		dmu_buf_t *db = dbp[i];
661 
662 		ASSERT(size > 0);
663 
664 		bufoff = uio->uio_loffset - db->db_offset;
665 		tocpy = (int)MIN(db->db_size - bufoff, size);
666 
667 		err = uiomove((char *)db->db_data + bufoff, tocpy,
668 		    UIO_READ, uio);
669 		if (err)
670 			break;
671 
672 		size -= tocpy;
673 	}
674 	dmu_buf_rele_array(dbp, numbufs, FTAG);
675 
676 	return (err);
677 }
678 
679 int
680 dmu_write_uio(objset_t *os, uint64_t object, uio_t *uio, uint64_t size,
681     dmu_tx_t *tx)
682 {
683 	dmu_buf_t **dbp;
684 	int numbufs, i;
685 	int err = 0;
686 
687 	if (size == 0)
688 		return (0);
689 
690 	err = dmu_buf_hold_array(os, object, uio->uio_loffset, size,
691 	    FALSE, FTAG, &numbufs, &dbp);
692 	if (err)
693 		return (err);
694 
695 	for (i = 0; i < numbufs; i++) {
696 		int tocpy;
697 		int bufoff;
698 		dmu_buf_t *db = dbp[i];
699 
700 		ASSERT(size > 0);
701 
702 		bufoff = uio->uio_loffset - db->db_offset;
703 		tocpy = (int)MIN(db->db_size - bufoff, size);
704 
705 		ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
706 
707 		if (tocpy == db->db_size)
708 			dmu_buf_will_fill(db, tx);
709 		else
710 			dmu_buf_will_dirty(db, tx);
711 
712 		/*
713 		 * XXX uiomove could block forever (eg. nfs-backed
714 		 * pages).  There needs to be a uiolockdown() function
715 		 * to lock the pages in memory, so that uiomove won't
716 		 * block.
717 		 */
718 		err = uiomove((char *)db->db_data + bufoff, tocpy,
719 		    UIO_WRITE, uio);
720 
721 		if (tocpy == db->db_size)
722 			dmu_buf_fill_done(db, tx);
723 
724 		if (err)
725 			break;
726 
727 		size -= tocpy;
728 	}
729 	dmu_buf_rele_array(dbp, numbufs, FTAG);
730 	return (err);
731 }
732 
733 int
734 dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
735     page_t *pp, dmu_tx_t *tx)
736 {
737 	dmu_buf_t **dbp;
738 	int numbufs, i;
739 	int err;
740 
741 	if (size == 0)
742 		return (0);
743 
744 	err = dmu_buf_hold_array(os, object, offset, size,
745 	    FALSE, FTAG, &numbufs, &dbp);
746 	if (err)
747 		return (err);
748 
749 	for (i = 0; i < numbufs; i++) {
750 		int tocpy, copied, thiscpy;
751 		int bufoff;
752 		dmu_buf_t *db = dbp[i];
753 		caddr_t va;
754 
755 		ASSERT(size > 0);
756 		ASSERT3U(db->db_size, >=, PAGESIZE);
757 
758 		bufoff = offset - db->db_offset;
759 		tocpy = (int)MIN(db->db_size - bufoff, size);
760 
761 		ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
762 
763 		if (tocpy == db->db_size)
764 			dmu_buf_will_fill(db, tx);
765 		else
766 			dmu_buf_will_dirty(db, tx);
767 
768 		for (copied = 0; copied < tocpy; copied += PAGESIZE) {
769 			ASSERT3U(pp->p_offset, ==, db->db_offset + bufoff);
770 			thiscpy = MIN(PAGESIZE, tocpy - copied);
771 			va = zfs_map_page(pp, S_READ);
772 			bcopy(va, (char *)db->db_data + bufoff, thiscpy);
773 			zfs_unmap_page(pp, va);
774 			pp = pp->p_next;
775 			bufoff += PAGESIZE;
776 		}
777 
778 		if (tocpy == db->db_size)
779 			dmu_buf_fill_done(db, tx);
780 
781 		if (err)
782 			break;
783 
784 		offset += tocpy;
785 		size -= tocpy;
786 	}
787 	dmu_buf_rele_array(dbp, numbufs, FTAG);
788 	return (err);
789 }
790 #endif
791 
792 typedef struct {
793 	dbuf_dirty_record_t	*dr;
794 	dmu_sync_cb_t		*done;
795 	void			*arg;
796 } dmu_sync_arg_t;
797 
798 /* ARGSUSED */
799 static void
800 dmu_sync_done(zio_t *zio, arc_buf_t *buf, void *varg)
801 {
802 	dmu_sync_arg_t *in = varg;
803 	dbuf_dirty_record_t *dr = in->dr;
804 	dmu_buf_impl_t *db = dr->dr_dbuf;
805 	dmu_sync_cb_t *done = in->done;
806 
807 	if (!BP_IS_HOLE(zio->io_bp)) {
808 		zio->io_bp->blk_fill = 1;
809 		BP_SET_TYPE(zio->io_bp, db->db_dnode->dn_type);
810 		BP_SET_LEVEL(zio->io_bp, 0);
811 	}
812 
813 	mutex_enter(&db->db_mtx);
814 	ASSERT(dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC);
815 	dr->dt.dl.dr_overridden_by = *zio->io_bp; /* structure assignment */
816 	dr->dt.dl.dr_override_state = DR_OVERRIDDEN;
817 	cv_broadcast(&db->db_changed);
818 	mutex_exit(&db->db_mtx);
819 
820 	if (done)
821 		done(&(db->db), in->arg);
822 
823 	kmem_free(in, sizeof (dmu_sync_arg_t));
824 }
825 
826 /*
827  * Intent log support: sync the block associated with db to disk.
828  * N.B. and XXX: the caller is responsible for making sure that the
829  * data isn't changing while dmu_sync() is writing it.
830  *
831  * Return values:
832  *
833  *	EEXIST: this txg has already been synced, so there's nothing to to.
834  *		The caller should not log the write.
835  *
836  *	ENOENT: the block was dbuf_free_range()'d, so there's nothing to do.
837  *		The caller should not log the write.
838  *
839  *	EALREADY: this block is already in the process of being synced.
840  *		The caller should track its progress (somehow).
841  *
842  *	EINPROGRESS: the IO has been initiated.
843  *		The caller should log this blkptr in the callback.
844  *
845  *	0: completed.  Sets *bp to the blkptr just written.
846  *		The caller should log this blkptr immediately.
847  */
848 int
849 dmu_sync(zio_t *pio, dmu_buf_t *db_fake,
850     blkptr_t *bp, uint64_t txg, dmu_sync_cb_t *done, void *arg)
851 {
852 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
853 	objset_impl_t *os = db->db_objset;
854 	dsl_pool_t *dp = os->os_dsl_dataset->ds_dir->dd_pool;
855 	tx_state_t *tx = &dp->dp_tx;
856 	dbuf_dirty_record_t *dr;
857 	dmu_sync_arg_t *in;
858 	zbookmark_t zb;
859 	writeprops_t wp = { 0 };
860 	zio_t *zio;
861 	int zio_flags;
862 	int err;
863 
864 	ASSERT(BP_IS_HOLE(bp));
865 	ASSERT(txg != 0);
866 
867 
868 	dprintf("dmu_sync txg=%llu, s,o,q %llu %llu %llu\n",
869 	    txg, tx->tx_synced_txg, tx->tx_open_txg, tx->tx_quiesced_txg);
870 
871 	/*
872 	 * XXX - would be nice if we could do this without suspending...
873 	 */
874 	txg_suspend(dp);
875 
876 	/*
877 	 * If this txg already synced, there's nothing to do.
878 	 */
879 	if (txg <= tx->tx_synced_txg) {
880 		txg_resume(dp);
881 		/*
882 		 * If we're running ziltest, we need the blkptr regardless.
883 		 */
884 		if (txg > spa_freeze_txg(dp->dp_spa)) {
885 			/* if db_blkptr == NULL, this was an empty write */
886 			if (db->db_blkptr)
887 				*bp = *db->db_blkptr; /* structure assignment */
888 			return (0);
889 		}
890 		return (EEXIST);
891 	}
892 
893 	mutex_enter(&db->db_mtx);
894 
895 	if (txg == tx->tx_syncing_txg) {
896 		while (db->db_data_pending) {
897 			/*
898 			 * IO is in-progress.  Wait for it to finish.
899 			 * XXX - would be nice to be able to somehow "attach"
900 			 * this zio to the parent zio passed in.
901 			 */
902 			cv_wait(&db->db_changed, &db->db_mtx);
903 			if (!db->db_data_pending &&
904 			    db->db_blkptr && BP_IS_HOLE(db->db_blkptr)) {
905 				/*
906 				 * IO was compressed away
907 				 */
908 				*bp = *db->db_blkptr; /* structure assignment */
909 				mutex_exit(&db->db_mtx);
910 				txg_resume(dp);
911 				return (0);
912 			}
913 			ASSERT(db->db_data_pending ||
914 			    (db->db_blkptr && db->db_blkptr->blk_birth == txg));
915 		}
916 
917 		if (db->db_blkptr && db->db_blkptr->blk_birth == txg) {
918 			/*
919 			 * IO is already completed.
920 			 */
921 			*bp = *db->db_blkptr; /* structure assignment */
922 			mutex_exit(&db->db_mtx);
923 			txg_resume(dp);
924 			return (0);
925 		}
926 	}
927 
928 	dr = db->db_last_dirty;
929 	while (dr && dr->dr_txg > txg)
930 		dr = dr->dr_next;
931 	if (dr == NULL || dr->dr_txg < txg) {
932 		/*
933 		 * This dbuf isn't dirty, must have been free_range'd.
934 		 * There's no need to log writes to freed blocks, so we're done.
935 		 */
936 		mutex_exit(&db->db_mtx);
937 		txg_resume(dp);
938 		return (ENOENT);
939 	}
940 
941 	ASSERT(dr->dr_txg == txg);
942 	if (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC) {
943 		/*
944 		 * We have already issued a sync write for this buffer.
945 		 */
946 		mutex_exit(&db->db_mtx);
947 		txg_resume(dp);
948 		return (EALREADY);
949 	} else if (dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
950 		/*
951 		 * This buffer has already been synced.  It could not
952 		 * have been dirtied since, or we would have cleared the state.
953 		 */
954 		*bp = dr->dt.dl.dr_overridden_by; /* structure assignment */
955 		mutex_exit(&db->db_mtx);
956 		txg_resume(dp);
957 		return (0);
958 	}
959 
960 	dr->dt.dl.dr_override_state = DR_IN_DMU_SYNC;
961 	in = kmem_alloc(sizeof (dmu_sync_arg_t), KM_SLEEP);
962 	in->dr = dr;
963 	in->done = done;
964 	in->arg = arg;
965 	mutex_exit(&db->db_mtx);
966 	txg_resume(dp);
967 
968 	zb.zb_objset = os->os_dsl_dataset->ds_object;
969 	zb.zb_object = db->db.db_object;
970 	zb.zb_level = db->db_level;
971 	zb.zb_blkid = db->db_blkid;
972 	zio_flags = ZIO_FLAG_MUSTSUCCEED;
973 	if (dmu_ot[db->db_dnode->dn_type].ot_metadata || zb.zb_level != 0)
974 		zio_flags |= ZIO_FLAG_METADATA;
975 	wp.wp_type = db->db_dnode->dn_type;
976 	wp.wp_copies = os->os_copies;
977 	wp.wp_level = db->db_level;
978 	wp.wp_dnchecksum = db->db_dnode->dn_checksum;
979 	wp.wp_oschecksum = os->os_checksum;
980 	wp.wp_dncompress = db->db_dnode->dn_compress;
981 	wp.wp_oscompress = os->os_compress;
982 	zio = arc_write(pio, os->os_spa, &wp,
983 	    DBUF_IS_L2CACHEABLE(db), txg, bp, dr->dt.dl.dr_data, NULL,
984 	    dmu_sync_done, in, ZIO_PRIORITY_SYNC_WRITE, zio_flags, &zb);
985 
986 	if (pio) {
987 		zio_nowait(zio);
988 		err = EINPROGRESS;
989 	} else {
990 		err = zio_wait(zio);
991 		ASSERT(err == 0);
992 	}
993 	return (err);
994 }
995 
996 int
997 dmu_object_set_blocksize(objset_t *os, uint64_t object, uint64_t size, int ibs,
998 	dmu_tx_t *tx)
999 {
1000 	dnode_t *dn;
1001 	int err;
1002 
1003 	err = dnode_hold(os->os, object, FTAG, &dn);
1004 	if (err)
1005 		return (err);
1006 	err = dnode_set_blksz(dn, size, ibs, tx);
1007 	dnode_rele(dn, FTAG);
1008 	return (err);
1009 }
1010 
1011 void
1012 dmu_object_set_checksum(objset_t *os, uint64_t object, uint8_t checksum,
1013 	dmu_tx_t *tx)
1014 {
1015 	dnode_t *dn;
1016 
1017 	/* XXX assumes dnode_hold will not get an i/o error */
1018 	(void) dnode_hold(os->os, object, FTAG, &dn);
1019 	ASSERT(checksum < ZIO_CHECKSUM_FUNCTIONS);
1020 	dn->dn_checksum = checksum;
1021 	dnode_setdirty(dn, tx);
1022 	dnode_rele(dn, FTAG);
1023 }
1024 
1025 void
1026 dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
1027 	dmu_tx_t *tx)
1028 {
1029 	dnode_t *dn;
1030 
1031 	/* XXX assumes dnode_hold will not get an i/o error */
1032 	(void) dnode_hold(os->os, object, FTAG, &dn);
1033 	ASSERT(compress < ZIO_COMPRESS_FUNCTIONS);
1034 	dn->dn_compress = compress;
1035 	dnode_setdirty(dn, tx);
1036 	dnode_rele(dn, FTAG);
1037 }
1038 
1039 int
1040 dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole, uint64_t *off)
1041 {
1042 	dnode_t *dn;
1043 	int i, err;
1044 
1045 	err = dnode_hold(os->os, object, FTAG, &dn);
1046 	if (err)
1047 		return (err);
1048 	/*
1049 	 * Sync any current changes before
1050 	 * we go trundling through the block pointers.
1051 	 */
1052 	for (i = 0; i < TXG_SIZE; i++) {
1053 		if (list_link_active(&dn->dn_dirty_link[i]))
1054 			break;
1055 	}
1056 	if (i != TXG_SIZE) {
1057 		dnode_rele(dn, FTAG);
1058 		txg_wait_synced(dmu_objset_pool(os), 0);
1059 		err = dnode_hold(os->os, object, FTAG, &dn);
1060 		if (err)
1061 			return (err);
1062 	}
1063 
1064 	err = dnode_next_offset(dn, (hole ? DNODE_FIND_HOLE : 0), off, 1, 1, 0);
1065 	dnode_rele(dn, FTAG);
1066 
1067 	return (err);
1068 }
1069 
1070 void
1071 dmu_object_info_from_dnode(dnode_t *dn, dmu_object_info_t *doi)
1072 {
1073 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
1074 	mutex_enter(&dn->dn_mtx);
1075 
1076 	doi->doi_data_block_size = dn->dn_datablksz;
1077 	doi->doi_metadata_block_size = dn->dn_indblkshift ?
1078 	    1ULL << dn->dn_indblkshift : 0;
1079 	doi->doi_indirection = dn->dn_nlevels;
1080 	doi->doi_checksum = dn->dn_checksum;
1081 	doi->doi_compress = dn->dn_compress;
1082 	doi->doi_physical_blks = (DN_USED_BYTES(dn->dn_phys) +
1083 	    SPA_MINBLOCKSIZE/2) >> SPA_MINBLOCKSHIFT;
1084 	doi->doi_max_block_offset = dn->dn_phys->dn_maxblkid;
1085 	doi->doi_type = dn->dn_type;
1086 	doi->doi_bonus_size = dn->dn_bonuslen;
1087 	doi->doi_bonus_type = dn->dn_bonustype;
1088 
1089 	mutex_exit(&dn->dn_mtx);
1090 	rw_exit(&dn->dn_struct_rwlock);
1091 }
1092 
1093 /*
1094  * Get information on a DMU object.
1095  * If doi is NULL, just indicates whether the object exists.
1096  */
1097 int
1098 dmu_object_info(objset_t *os, uint64_t object, dmu_object_info_t *doi)
1099 {
1100 	dnode_t *dn;
1101 	int err = dnode_hold(os->os, object, FTAG, &dn);
1102 
1103 	if (err)
1104 		return (err);
1105 
1106 	if (doi != NULL)
1107 		dmu_object_info_from_dnode(dn, doi);
1108 
1109 	dnode_rele(dn, FTAG);
1110 	return (0);
1111 }
1112 
1113 /*
1114  * As above, but faster; can be used when you have a held dbuf in hand.
1115  */
1116 void
1117 dmu_object_info_from_db(dmu_buf_t *db, dmu_object_info_t *doi)
1118 {
1119 	dmu_object_info_from_dnode(((dmu_buf_impl_t *)db)->db_dnode, doi);
1120 }
1121 
1122 /*
1123  * Faster still when you only care about the size.
1124  * This is specifically optimized for zfs_getattr().
1125  */
1126 void
1127 dmu_object_size_from_db(dmu_buf_t *db, uint32_t *blksize, u_longlong_t *nblk512)
1128 {
1129 	dnode_t *dn = ((dmu_buf_impl_t *)db)->db_dnode;
1130 
1131 	*blksize = dn->dn_datablksz;
1132 	/* add 1 for dnode space */
1133 	*nblk512 = ((DN_USED_BYTES(dn->dn_phys) + SPA_MINBLOCKSIZE/2) >>
1134 	    SPA_MINBLOCKSHIFT) + 1;
1135 }
1136 
1137 void
1138 byteswap_uint64_array(void *vbuf, size_t size)
1139 {
1140 	uint64_t *buf = vbuf;
1141 	size_t count = size >> 3;
1142 	int i;
1143 
1144 	ASSERT((size & 7) == 0);
1145 
1146 	for (i = 0; i < count; i++)
1147 		buf[i] = BSWAP_64(buf[i]);
1148 }
1149 
1150 void
1151 byteswap_uint32_array(void *vbuf, size_t size)
1152 {
1153 	uint32_t *buf = vbuf;
1154 	size_t count = size >> 2;
1155 	int i;
1156 
1157 	ASSERT((size & 3) == 0);
1158 
1159 	for (i = 0; i < count; i++)
1160 		buf[i] = BSWAP_32(buf[i]);
1161 }
1162 
1163 void
1164 byteswap_uint16_array(void *vbuf, size_t size)
1165 {
1166 	uint16_t *buf = vbuf;
1167 	size_t count = size >> 1;
1168 	int i;
1169 
1170 	ASSERT((size & 1) == 0);
1171 
1172 	for (i = 0; i < count; i++)
1173 		buf[i] = BSWAP_16(buf[i]);
1174 }
1175 
1176 /* ARGSUSED */
1177 void
1178 byteswap_uint8_array(void *vbuf, size_t size)
1179 {
1180 }
1181 
1182 void
1183 dmu_init(void)
1184 {
1185 	dbuf_init();
1186 	dnode_init();
1187 	arc_init();
1188 	l2arc_init();
1189 }
1190 
1191 void
1192 dmu_fini(void)
1193 {
1194 	arc_fini();
1195 	dnode_fini();
1196 	dbuf_fini();
1197 	l2arc_fini();
1198 }
1199