xref: /titanic_41/usr/src/uts/common/fs/zfs/dmu.c (revision 5f9bb2f350e19a276d3aff33afb5fc94fb47f02a)
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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
24  */
25 /* Copyright (c) 2013 by Saso Kiselkov. All rights reserved. */
26 /* Copyright (c) 2013, Joyent, Inc. All rights reserved. */
27 /* Copyright (c) 2014, Nexenta Systems, Inc. All rights reserved. */
28 
29 #include <sys/dmu.h>
30 #include <sys/dmu_impl.h>
31 #include <sys/dmu_tx.h>
32 #include <sys/dbuf.h>
33 #include <sys/dnode.h>
34 #include <sys/zfs_context.h>
35 #include <sys/dmu_objset.h>
36 #include <sys/dmu_traverse.h>
37 #include <sys/dsl_dataset.h>
38 #include <sys/dsl_dir.h>
39 #include <sys/dsl_pool.h>
40 #include <sys/dsl_synctask.h>
41 #include <sys/dsl_prop.h>
42 #include <sys/dmu_zfetch.h>
43 #include <sys/zfs_ioctl.h>
44 #include <sys/zap.h>
45 #include <sys/zio_checksum.h>
46 #include <sys/zio_compress.h>
47 #include <sys/sa.h>
48 #include <sys/zfeature.h>
49 #ifdef _KERNEL
50 #include <sys/vmsystm.h>
51 #include <sys/zfs_znode.h>
52 #endif
53 
54 /*
55  * Enable/disable nopwrite feature.
56  */
57 int zfs_nopwrite_enabled = 1;
58 
59 const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES] = {
60 	{	DMU_BSWAP_UINT8,	TRUE,	"unallocated"		},
61 	{	DMU_BSWAP_ZAP,		TRUE,	"object directory"	},
62 	{	DMU_BSWAP_UINT64,	TRUE,	"object array"		},
63 	{	DMU_BSWAP_UINT8,	TRUE,	"packed nvlist"		},
64 	{	DMU_BSWAP_UINT64,	TRUE,	"packed nvlist size"	},
65 	{	DMU_BSWAP_UINT64,	TRUE,	"bpobj"			},
66 	{	DMU_BSWAP_UINT64,	TRUE,	"bpobj header"		},
67 	{	DMU_BSWAP_UINT64,	TRUE,	"SPA space map header"	},
68 	{	DMU_BSWAP_UINT64,	TRUE,	"SPA space map"		},
69 	{	DMU_BSWAP_UINT64,	TRUE,	"ZIL intent log"	},
70 	{	DMU_BSWAP_DNODE,	TRUE,	"DMU dnode"		},
71 	{	DMU_BSWAP_OBJSET,	TRUE,	"DMU objset"		},
72 	{	DMU_BSWAP_UINT64,	TRUE,	"DSL directory"		},
73 	{	DMU_BSWAP_ZAP,		TRUE,	"DSL directory child map"},
74 	{	DMU_BSWAP_ZAP,		TRUE,	"DSL dataset snap map"	},
75 	{	DMU_BSWAP_ZAP,		TRUE,	"DSL props"		},
76 	{	DMU_BSWAP_UINT64,	TRUE,	"DSL dataset"		},
77 	{	DMU_BSWAP_ZNODE,	TRUE,	"ZFS znode"		},
78 	{	DMU_BSWAP_OLDACL,	TRUE,	"ZFS V0 ACL"		},
79 	{	DMU_BSWAP_UINT8,	FALSE,	"ZFS plain file"	},
80 	{	DMU_BSWAP_ZAP,		TRUE,	"ZFS directory"		},
81 	{	DMU_BSWAP_ZAP,		TRUE,	"ZFS master node"	},
82 	{	DMU_BSWAP_ZAP,		TRUE,	"ZFS delete queue"	},
83 	{	DMU_BSWAP_UINT8,	FALSE,	"zvol object"		},
84 	{	DMU_BSWAP_ZAP,		TRUE,	"zvol prop"		},
85 	{	DMU_BSWAP_UINT8,	FALSE,	"other uint8[]"		},
86 	{	DMU_BSWAP_UINT64,	FALSE,	"other uint64[]"	},
87 	{	DMU_BSWAP_ZAP,		TRUE,	"other ZAP"		},
88 	{	DMU_BSWAP_ZAP,		TRUE,	"persistent error log"	},
89 	{	DMU_BSWAP_UINT8,	TRUE,	"SPA history"		},
90 	{	DMU_BSWAP_UINT64,	TRUE,	"SPA history offsets"	},
91 	{	DMU_BSWAP_ZAP,		TRUE,	"Pool properties"	},
92 	{	DMU_BSWAP_ZAP,		TRUE,	"DSL permissions"	},
93 	{	DMU_BSWAP_ACL,		TRUE,	"ZFS ACL"		},
94 	{	DMU_BSWAP_UINT8,	TRUE,	"ZFS SYSACL"		},
95 	{	DMU_BSWAP_UINT8,	TRUE,	"FUID table"		},
96 	{	DMU_BSWAP_UINT64,	TRUE,	"FUID table size"	},
97 	{	DMU_BSWAP_ZAP,		TRUE,	"DSL dataset next clones"},
98 	{	DMU_BSWAP_ZAP,		TRUE,	"scan work queue"	},
99 	{	DMU_BSWAP_ZAP,		TRUE,	"ZFS user/group used"	},
100 	{	DMU_BSWAP_ZAP,		TRUE,	"ZFS user/group quota"	},
101 	{	DMU_BSWAP_ZAP,		TRUE,	"snapshot refcount tags"},
102 	{	DMU_BSWAP_ZAP,		TRUE,	"DDT ZAP algorithm"	},
103 	{	DMU_BSWAP_ZAP,		TRUE,	"DDT statistics"	},
104 	{	DMU_BSWAP_UINT8,	TRUE,	"System attributes"	},
105 	{	DMU_BSWAP_ZAP,		TRUE,	"SA master node"	},
106 	{	DMU_BSWAP_ZAP,		TRUE,	"SA attr registration"	},
107 	{	DMU_BSWAP_ZAP,		TRUE,	"SA attr layouts"	},
108 	{	DMU_BSWAP_ZAP,		TRUE,	"scan translations"	},
109 	{	DMU_BSWAP_UINT8,	FALSE,	"deduplicated block"	},
110 	{	DMU_BSWAP_ZAP,		TRUE,	"DSL deadlist map"	},
111 	{	DMU_BSWAP_UINT64,	TRUE,	"DSL deadlist map hdr"	},
112 	{	DMU_BSWAP_ZAP,		TRUE,	"DSL dir clones"	},
113 	{	DMU_BSWAP_UINT64,	TRUE,	"bpobj subobj"		}
114 };
115 
116 const dmu_object_byteswap_info_t dmu_ot_byteswap[DMU_BSWAP_NUMFUNCS] = {
117 	{	byteswap_uint8_array,	"uint8"		},
118 	{	byteswap_uint16_array,	"uint16"	},
119 	{	byteswap_uint32_array,	"uint32"	},
120 	{	byteswap_uint64_array,	"uint64"	},
121 	{	zap_byteswap,		"zap"		},
122 	{	dnode_buf_byteswap,	"dnode"		},
123 	{	dmu_objset_byteswap,	"objset"	},
124 	{	zfs_znode_byteswap,	"znode"		},
125 	{	zfs_oldacl_byteswap,	"oldacl"	},
126 	{	zfs_acl_byteswap,	"acl"		}
127 };
128 
129 int
dmu_buf_hold_noread(objset_t * os,uint64_t object,uint64_t offset,void * tag,dmu_buf_t ** dbp)130 dmu_buf_hold_noread(objset_t *os, uint64_t object, uint64_t offset,
131     void *tag, dmu_buf_t **dbp)
132 {
133 	dnode_t *dn;
134 	uint64_t blkid;
135 	dmu_buf_impl_t *db;
136 	int err;
137 
138 	err = dnode_hold(os, object, FTAG, &dn);
139 	if (err)
140 		return (err);
141 	blkid = dbuf_whichblock(dn, 0, offset);
142 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
143 	db = dbuf_hold(dn, blkid, tag);
144 	rw_exit(&dn->dn_struct_rwlock);
145 	dnode_rele(dn, FTAG);
146 
147 	if (db == NULL) {
148 		*dbp = NULL;
149 		return (SET_ERROR(EIO));
150 	}
151 
152 	*dbp = &db->db;
153 	return (err);
154 }
155 
156 int
dmu_buf_hold(objset_t * os,uint64_t object,uint64_t offset,void * tag,dmu_buf_t ** dbp,int flags)157 dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
158     void *tag, dmu_buf_t **dbp, int flags)
159 {
160 	int err;
161 	int db_flags = DB_RF_CANFAIL;
162 
163 	if (flags & DMU_READ_NO_PREFETCH)
164 		db_flags |= DB_RF_NOPREFETCH;
165 
166 	err = dmu_buf_hold_noread(os, object, offset, tag, dbp);
167 	if (err == 0) {
168 		dmu_buf_impl_t *db = (dmu_buf_impl_t *)(*dbp);
169 		err = dbuf_read(db, NULL, db_flags);
170 		if (err != 0) {
171 			dbuf_rele(db, tag);
172 			*dbp = NULL;
173 		}
174 	}
175 
176 	return (err);
177 }
178 
179 int
dmu_bonus_max(void)180 dmu_bonus_max(void)
181 {
182 	return (DN_MAX_BONUSLEN);
183 }
184 
185 int
dmu_set_bonus(dmu_buf_t * db_fake,int newsize,dmu_tx_t * tx)186 dmu_set_bonus(dmu_buf_t *db_fake, int newsize, dmu_tx_t *tx)
187 {
188 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
189 	dnode_t *dn;
190 	int error;
191 
192 	DB_DNODE_ENTER(db);
193 	dn = DB_DNODE(db);
194 
195 	if (dn->dn_bonus != db) {
196 		error = SET_ERROR(EINVAL);
197 	} else if (newsize < 0 || newsize > db_fake->db_size) {
198 		error = SET_ERROR(EINVAL);
199 	} else {
200 		dnode_setbonuslen(dn, newsize, tx);
201 		error = 0;
202 	}
203 
204 	DB_DNODE_EXIT(db);
205 	return (error);
206 }
207 
208 int
dmu_set_bonustype(dmu_buf_t * db_fake,dmu_object_type_t type,dmu_tx_t * tx)209 dmu_set_bonustype(dmu_buf_t *db_fake, dmu_object_type_t type, dmu_tx_t *tx)
210 {
211 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
212 	dnode_t *dn;
213 	int error;
214 
215 	DB_DNODE_ENTER(db);
216 	dn = DB_DNODE(db);
217 
218 	if (!DMU_OT_IS_VALID(type)) {
219 		error = SET_ERROR(EINVAL);
220 	} else if (dn->dn_bonus != db) {
221 		error = SET_ERROR(EINVAL);
222 	} else {
223 		dnode_setbonus_type(dn, type, tx);
224 		error = 0;
225 	}
226 
227 	DB_DNODE_EXIT(db);
228 	return (error);
229 }
230 
231 dmu_object_type_t
dmu_get_bonustype(dmu_buf_t * db_fake)232 dmu_get_bonustype(dmu_buf_t *db_fake)
233 {
234 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
235 	dnode_t *dn;
236 	dmu_object_type_t type;
237 
238 	DB_DNODE_ENTER(db);
239 	dn = DB_DNODE(db);
240 	type = dn->dn_bonustype;
241 	DB_DNODE_EXIT(db);
242 
243 	return (type);
244 }
245 
246 int
dmu_rm_spill(objset_t * os,uint64_t object,dmu_tx_t * tx)247 dmu_rm_spill(objset_t *os, uint64_t object, dmu_tx_t *tx)
248 {
249 	dnode_t *dn;
250 	int error;
251 
252 	error = dnode_hold(os, object, FTAG, &dn);
253 	dbuf_rm_spill(dn, tx);
254 	rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
255 	dnode_rm_spill(dn, tx);
256 	rw_exit(&dn->dn_struct_rwlock);
257 	dnode_rele(dn, FTAG);
258 	return (error);
259 }
260 
261 /*
262  * returns ENOENT, EIO, or 0.
263  */
264 int
dmu_bonus_hold(objset_t * os,uint64_t object,void * tag,dmu_buf_t ** dbp)265 dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **dbp)
266 {
267 	dnode_t *dn;
268 	dmu_buf_impl_t *db;
269 	int error;
270 
271 	error = dnode_hold(os, object, FTAG, &dn);
272 	if (error)
273 		return (error);
274 
275 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
276 	if (dn->dn_bonus == NULL) {
277 		rw_exit(&dn->dn_struct_rwlock);
278 		rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
279 		if (dn->dn_bonus == NULL)
280 			dbuf_create_bonus(dn);
281 	}
282 	db = dn->dn_bonus;
283 
284 	/* as long as the bonus buf is held, the dnode will be held */
285 	if (refcount_add(&db->db_holds, tag) == 1) {
286 		VERIFY(dnode_add_ref(dn, db));
287 		atomic_inc_32(&dn->dn_dbufs_count);
288 	}
289 
290 	/*
291 	 * Wait to drop dn_struct_rwlock until after adding the bonus dbuf's
292 	 * hold and incrementing the dbuf count to ensure that dnode_move() sees
293 	 * a dnode hold for every dbuf.
294 	 */
295 	rw_exit(&dn->dn_struct_rwlock);
296 
297 	dnode_rele(dn, FTAG);
298 
299 	VERIFY(0 == dbuf_read(db, NULL, DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH));
300 
301 	*dbp = &db->db;
302 	return (0);
303 }
304 
305 /*
306  * returns ENOENT, EIO, or 0.
307  *
308  * This interface will allocate a blank spill dbuf when a spill blk
309  * doesn't already exist on the dnode.
310  *
311  * if you only want to find an already existing spill db, then
312  * dmu_spill_hold_existing() should be used.
313  */
314 int
dmu_spill_hold_by_dnode(dnode_t * dn,uint32_t flags,void * tag,dmu_buf_t ** dbp)315 dmu_spill_hold_by_dnode(dnode_t *dn, uint32_t flags, void *tag, dmu_buf_t **dbp)
316 {
317 	dmu_buf_impl_t *db = NULL;
318 	int err;
319 
320 	if ((flags & DB_RF_HAVESTRUCT) == 0)
321 		rw_enter(&dn->dn_struct_rwlock, RW_READER);
322 
323 	db = dbuf_hold(dn, DMU_SPILL_BLKID, tag);
324 
325 	if ((flags & DB_RF_HAVESTRUCT) == 0)
326 		rw_exit(&dn->dn_struct_rwlock);
327 
328 	ASSERT(db != NULL);
329 	err = dbuf_read(db, NULL, flags);
330 	if (err == 0)
331 		*dbp = &db->db;
332 	else
333 		dbuf_rele(db, tag);
334 	return (err);
335 }
336 
337 int
dmu_spill_hold_existing(dmu_buf_t * bonus,void * tag,dmu_buf_t ** dbp)338 dmu_spill_hold_existing(dmu_buf_t *bonus, void *tag, dmu_buf_t **dbp)
339 {
340 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)bonus;
341 	dnode_t *dn;
342 	int err;
343 
344 	DB_DNODE_ENTER(db);
345 	dn = DB_DNODE(db);
346 
347 	if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_SA) {
348 		err = SET_ERROR(EINVAL);
349 	} else {
350 		rw_enter(&dn->dn_struct_rwlock, RW_READER);
351 
352 		if (!dn->dn_have_spill) {
353 			err = SET_ERROR(ENOENT);
354 		} else {
355 			err = dmu_spill_hold_by_dnode(dn,
356 			    DB_RF_HAVESTRUCT | DB_RF_CANFAIL, tag, dbp);
357 		}
358 
359 		rw_exit(&dn->dn_struct_rwlock);
360 	}
361 
362 	DB_DNODE_EXIT(db);
363 	return (err);
364 }
365 
366 int
dmu_spill_hold_by_bonus(dmu_buf_t * bonus,void * tag,dmu_buf_t ** dbp)367 dmu_spill_hold_by_bonus(dmu_buf_t *bonus, void *tag, dmu_buf_t **dbp)
368 {
369 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)bonus;
370 	dnode_t *dn;
371 	int err;
372 
373 	DB_DNODE_ENTER(db);
374 	dn = DB_DNODE(db);
375 	err = dmu_spill_hold_by_dnode(dn, DB_RF_CANFAIL, tag, dbp);
376 	DB_DNODE_EXIT(db);
377 
378 	return (err);
379 }
380 
381 /*
382  * Note: longer-term, we should modify all of the dmu_buf_*() interfaces
383  * to take a held dnode rather than <os, object> -- the lookup is wasteful,
384  * and can induce severe lock contention when writing to several files
385  * whose dnodes are in the same block.
386  */
387 static int
dmu_buf_hold_array_by_dnode(dnode_t * dn,uint64_t offset,uint64_t length,int read,void * tag,int * numbufsp,dmu_buf_t *** dbpp,uint32_t flags)388 dmu_buf_hold_array_by_dnode(dnode_t *dn, uint64_t offset, uint64_t length,
389     int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp, uint32_t flags)
390 {
391 	dmu_buf_t **dbp;
392 	uint64_t blkid, nblks, i;
393 	uint32_t dbuf_flags;
394 	int err;
395 	zio_t *zio;
396 
397 	ASSERT(length <= DMU_MAX_ACCESS);
398 
399 	dbuf_flags = DB_RF_CANFAIL | DB_RF_NEVERWAIT | DB_RF_HAVESTRUCT;
400 	if (flags & DMU_READ_NO_PREFETCH || length > zfetch_array_rd_sz)
401 		dbuf_flags |= DB_RF_NOPREFETCH;
402 
403 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
404 	if (dn->dn_datablkshift) {
405 		int blkshift = dn->dn_datablkshift;
406 		nblks = (P2ROUNDUP(offset+length, 1ULL<<blkshift) -
407 		    P2ALIGN(offset, 1ULL<<blkshift)) >> blkshift;
408 	} else {
409 		if (offset + length > dn->dn_datablksz) {
410 			zfs_panic_recover("zfs: accessing past end of object "
411 			    "%llx/%llx (size=%u access=%llu+%llu)",
412 			    (longlong_t)dn->dn_objset->
413 			    os_dsl_dataset->ds_object,
414 			    (longlong_t)dn->dn_object, dn->dn_datablksz,
415 			    (longlong_t)offset, (longlong_t)length);
416 			rw_exit(&dn->dn_struct_rwlock);
417 			return (SET_ERROR(EIO));
418 		}
419 		nblks = 1;
420 	}
421 	dbp = kmem_zalloc(sizeof (dmu_buf_t *) * nblks, KM_SLEEP);
422 
423 	zio = zio_root(dn->dn_objset->os_spa, NULL, NULL, ZIO_FLAG_CANFAIL);
424 	blkid = dbuf_whichblock(dn, 0, offset);
425 	for (i = 0; i < nblks; i++) {
426 		dmu_buf_impl_t *db = dbuf_hold(dn, blkid+i, tag);
427 		if (db == NULL) {
428 			rw_exit(&dn->dn_struct_rwlock);
429 			dmu_buf_rele_array(dbp, nblks, tag);
430 			zio_nowait(zio);
431 			return (SET_ERROR(EIO));
432 		}
433 		/* initiate async i/o */
434 		if (read) {
435 			(void) dbuf_read(db, zio, dbuf_flags);
436 		}
437 		dbp[i] = &db->db;
438 	}
439 	rw_exit(&dn->dn_struct_rwlock);
440 
441 	/* wait for async i/o */
442 	err = zio_wait(zio);
443 	if (err) {
444 		dmu_buf_rele_array(dbp, nblks, tag);
445 		return (err);
446 	}
447 
448 	/* wait for other io to complete */
449 	if (read) {
450 		for (i = 0; i < nblks; i++) {
451 			dmu_buf_impl_t *db = (dmu_buf_impl_t *)dbp[i];
452 			mutex_enter(&db->db_mtx);
453 			while (db->db_state == DB_READ ||
454 			    db->db_state == DB_FILL)
455 				cv_wait(&db->db_changed, &db->db_mtx);
456 			if (db->db_state == DB_UNCACHED)
457 				err = SET_ERROR(EIO);
458 			mutex_exit(&db->db_mtx);
459 			if (err) {
460 				dmu_buf_rele_array(dbp, nblks, tag);
461 				return (err);
462 			}
463 		}
464 	}
465 
466 	*numbufsp = nblks;
467 	*dbpp = dbp;
468 	return (0);
469 }
470 
471 static int
dmu_buf_hold_array(objset_t * os,uint64_t object,uint64_t offset,uint64_t length,int read,void * tag,int * numbufsp,dmu_buf_t *** dbpp)472 dmu_buf_hold_array(objset_t *os, uint64_t object, uint64_t offset,
473     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp)
474 {
475 	dnode_t *dn;
476 	int err;
477 
478 	err = dnode_hold(os, object, FTAG, &dn);
479 	if (err)
480 		return (err);
481 
482 	err = dmu_buf_hold_array_by_dnode(dn, offset, length, read, tag,
483 	    numbufsp, dbpp, DMU_READ_PREFETCH);
484 
485 	dnode_rele(dn, FTAG);
486 
487 	return (err);
488 }
489 
490 int
dmu_buf_hold_array_by_bonus(dmu_buf_t * db_fake,uint64_t offset,uint64_t length,int read,void * tag,int * numbufsp,dmu_buf_t *** dbpp)491 dmu_buf_hold_array_by_bonus(dmu_buf_t *db_fake, uint64_t offset,
492     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp)
493 {
494 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
495 	dnode_t *dn;
496 	int err;
497 
498 	DB_DNODE_ENTER(db);
499 	dn = DB_DNODE(db);
500 	err = dmu_buf_hold_array_by_dnode(dn, offset, length, read, tag,
501 	    numbufsp, dbpp, DMU_READ_PREFETCH);
502 	DB_DNODE_EXIT(db);
503 
504 	return (err);
505 }
506 
507 void
dmu_buf_rele_array(dmu_buf_t ** dbp_fake,int numbufs,void * tag)508 dmu_buf_rele_array(dmu_buf_t **dbp_fake, int numbufs, void *tag)
509 {
510 	int i;
511 	dmu_buf_impl_t **dbp = (dmu_buf_impl_t **)dbp_fake;
512 
513 	if (numbufs == 0)
514 		return;
515 
516 	for (i = 0; i < numbufs; i++) {
517 		if (dbp[i])
518 			dbuf_rele(dbp[i], tag);
519 	}
520 
521 	kmem_free(dbp, sizeof (dmu_buf_t *) * numbufs);
522 }
523 
524 /*
525  * Issue prefetch i/os for the given blocks.  If level is greater than 0, the
526  * indirect blocks prefeteched will be those that point to the blocks containing
527  * the data starting at offset, and continuing to offset + len.
528  *
529  * Note that if the indirect blocks above the blocks being prefetched are not in
530  * cache, they will be asychronously read in.
531  */
532 void
dmu_prefetch(objset_t * os,uint64_t object,int64_t level,uint64_t offset,uint64_t len,zio_priority_t pri)533 dmu_prefetch(objset_t *os, uint64_t object, int64_t level, uint64_t offset,
534     uint64_t len, zio_priority_t pri)
535 {
536 	dnode_t *dn;
537 	uint64_t blkid;
538 	int nblks, err;
539 
540 	if (zfs_prefetch_disable)
541 		return;
542 
543 	if (len == 0) {  /* they're interested in the bonus buffer */
544 		dn = DMU_META_DNODE(os);
545 
546 		if (object == 0 || object >= DN_MAX_OBJECT)
547 			return;
548 
549 		rw_enter(&dn->dn_struct_rwlock, RW_READER);
550 		blkid = dbuf_whichblock(dn, level,
551 		    object * sizeof (dnode_phys_t));
552 		dbuf_prefetch(dn, level, blkid, pri, 0);
553 		rw_exit(&dn->dn_struct_rwlock);
554 		return;
555 	}
556 
557 	/*
558 	 * XXX - Note, if the dnode for the requested object is not
559 	 * already cached, we will do a *synchronous* read in the
560 	 * dnode_hold() call.  The same is true for any indirects.
561 	 */
562 	err = dnode_hold(os, object, FTAG, &dn);
563 	if (err != 0)
564 		return;
565 
566 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
567 	/*
568 	 * offset + len - 1 is the last byte we want to prefetch for, and offset
569 	 * is the first.  Then dbuf_whichblk(dn, level, off + len - 1) is the
570 	 * last block we want to prefetch, and dbuf_whichblock(dn, level,
571 	 * offset)  is the first.  Then the number we need to prefetch is the
572 	 * last - first + 1.
573 	 */
574 	if (level > 0 || dn->dn_datablkshift != 0) {
575 		nblks = dbuf_whichblock(dn, level, offset + len - 1) -
576 		    dbuf_whichblock(dn, level, offset) + 1;
577 	} else {
578 		nblks = (offset < dn->dn_datablksz);
579 	}
580 
581 	if (nblks != 0) {
582 		blkid = dbuf_whichblock(dn, level, offset);
583 		for (int i = 0; i < nblks; i++)
584 			dbuf_prefetch(dn, level, blkid + i, pri, 0);
585 	}
586 
587 	rw_exit(&dn->dn_struct_rwlock);
588 
589 	dnode_rele(dn, FTAG);
590 }
591 
592 /*
593  * Get the next "chunk" of file data to free.  We traverse the file from
594  * the end so that the file gets shorter over time (if we crashes in the
595  * middle, this will leave us in a better state).  We find allocated file
596  * data by simply searching the allocated level 1 indirects.
597  *
598  * On input, *start should be the first offset that does not need to be
599  * freed (e.g. "offset + length").  On return, *start will be the first
600  * offset that should be freed.
601  */
602 static int
get_next_chunk(dnode_t * dn,uint64_t * start,uint64_t minimum)603 get_next_chunk(dnode_t *dn, uint64_t *start, uint64_t minimum)
604 {
605 	uint64_t maxblks = DMU_MAX_ACCESS >> (dn->dn_indblkshift + 1);
606 	/* bytes of data covered by a level-1 indirect block */
607 	uint64_t iblkrange =
608 	    dn->dn_datablksz * EPB(dn->dn_indblkshift, SPA_BLKPTRSHIFT);
609 
610 	ASSERT3U(minimum, <=, *start);
611 
612 	if (*start - minimum <= iblkrange * maxblks) {
613 		*start = minimum;
614 		return (0);
615 	}
616 	ASSERT(ISP2(iblkrange));
617 
618 	for (uint64_t blks = 0; *start > minimum && blks < maxblks; blks++) {
619 		int err;
620 
621 		/*
622 		 * dnode_next_offset(BACKWARDS) will find an allocated L1
623 		 * indirect block at or before the input offset.  We must
624 		 * decrement *start so that it is at the end of the region
625 		 * to search.
626 		 */
627 		(*start)--;
628 		err = dnode_next_offset(dn,
629 		    DNODE_FIND_BACKWARDS, start, 2, 1, 0);
630 
631 		/* if there are no indirect blocks before start, we are done */
632 		if (err == ESRCH) {
633 			*start = minimum;
634 			break;
635 		} else if (err != 0) {
636 			return (err);
637 		}
638 
639 		/* set start to the beginning of this L1 indirect */
640 		*start = P2ALIGN(*start, iblkrange);
641 	}
642 	if (*start < minimum)
643 		*start = minimum;
644 	return (0);
645 }
646 
647 static int
dmu_free_long_range_impl(objset_t * os,dnode_t * dn,uint64_t offset,uint64_t length)648 dmu_free_long_range_impl(objset_t *os, dnode_t *dn, uint64_t offset,
649     uint64_t length)
650 {
651 	uint64_t object_size = (dn->dn_maxblkid + 1) * dn->dn_datablksz;
652 	int err;
653 
654 	if (offset >= object_size)
655 		return (0);
656 
657 	if (length == DMU_OBJECT_END || offset + length > object_size)
658 		length = object_size - offset;
659 
660 	while (length != 0) {
661 		uint64_t chunk_end, chunk_begin;
662 
663 		chunk_end = chunk_begin = offset + length;
664 
665 		/* move chunk_begin backwards to the beginning of this chunk */
666 		err = get_next_chunk(dn, &chunk_begin, offset);
667 		if (err)
668 			return (err);
669 		ASSERT3U(chunk_begin, >=, offset);
670 		ASSERT3U(chunk_begin, <=, chunk_end);
671 
672 		dmu_tx_t *tx = dmu_tx_create(os);
673 		dmu_tx_hold_free(tx, dn->dn_object,
674 		    chunk_begin, chunk_end - chunk_begin);
675 
676 		/*
677 		 * Mark this transaction as typically resulting in a net
678 		 * reduction in space used.
679 		 */
680 		dmu_tx_mark_netfree(tx);
681 		err = dmu_tx_assign(tx, TXG_WAIT);
682 		if (err) {
683 			dmu_tx_abort(tx);
684 			return (err);
685 		}
686 		dnode_free_range(dn, chunk_begin, chunk_end - chunk_begin, tx);
687 		dmu_tx_commit(tx);
688 
689 		length -= chunk_end - chunk_begin;
690 	}
691 	return (0);
692 }
693 
694 int
dmu_free_long_range(objset_t * os,uint64_t object,uint64_t offset,uint64_t length)695 dmu_free_long_range(objset_t *os, uint64_t object,
696     uint64_t offset, uint64_t length)
697 {
698 	dnode_t *dn;
699 	int err;
700 
701 	err = dnode_hold(os, object, FTAG, &dn);
702 	if (err != 0)
703 		return (err);
704 	err = dmu_free_long_range_impl(os, dn, offset, length);
705 
706 	/*
707 	 * It is important to zero out the maxblkid when freeing the entire
708 	 * file, so that (a) subsequent calls to dmu_free_long_range_impl()
709 	 * will take the fast path, and (b) dnode_reallocate() can verify
710 	 * that the entire file has been freed.
711 	 */
712 	if (err == 0 && offset == 0 && length == DMU_OBJECT_END)
713 		dn->dn_maxblkid = 0;
714 
715 	dnode_rele(dn, FTAG);
716 	return (err);
717 }
718 
719 int
dmu_free_long_object(objset_t * os,uint64_t object)720 dmu_free_long_object(objset_t *os, uint64_t object)
721 {
722 	dmu_tx_t *tx;
723 	int err;
724 
725 	err = dmu_free_long_range(os, object, 0, DMU_OBJECT_END);
726 	if (err != 0)
727 		return (err);
728 
729 	tx = dmu_tx_create(os);
730 	dmu_tx_hold_bonus(tx, object);
731 	dmu_tx_hold_free(tx, object, 0, DMU_OBJECT_END);
732 	dmu_tx_mark_netfree(tx);
733 	err = dmu_tx_assign(tx, TXG_WAIT);
734 	if (err == 0) {
735 		err = dmu_object_free(os, object, tx);
736 		dmu_tx_commit(tx);
737 	} else {
738 		dmu_tx_abort(tx);
739 	}
740 
741 	return (err);
742 }
743 
744 int
dmu_free_range(objset_t * os,uint64_t object,uint64_t offset,uint64_t size,dmu_tx_t * tx)745 dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
746     uint64_t size, dmu_tx_t *tx)
747 {
748 	dnode_t *dn;
749 	int err = dnode_hold(os, object, FTAG, &dn);
750 	if (err)
751 		return (err);
752 	ASSERT(offset < UINT64_MAX);
753 	ASSERT(size == -1ULL || size <= UINT64_MAX - offset);
754 	dnode_free_range(dn, offset, size, tx);
755 	dnode_rele(dn, FTAG);
756 	return (0);
757 }
758 
759 int
dmu_read(objset_t * os,uint64_t object,uint64_t offset,uint64_t size,void * buf,uint32_t flags)760 dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
761     void *buf, uint32_t flags)
762 {
763 	dnode_t *dn;
764 	dmu_buf_t **dbp;
765 	int numbufs, err;
766 
767 	err = dnode_hold(os, object, FTAG, &dn);
768 	if (err)
769 		return (err);
770 
771 	/*
772 	 * Deal with odd block sizes, where there can't be data past the first
773 	 * block.  If we ever do the tail block optimization, we will need to
774 	 * handle that here as well.
775 	 */
776 	if (dn->dn_maxblkid == 0) {
777 		int newsz = offset > dn->dn_datablksz ? 0 :
778 		    MIN(size, dn->dn_datablksz - offset);
779 		bzero((char *)buf + newsz, size - newsz);
780 		size = newsz;
781 	}
782 
783 	while (size > 0) {
784 		uint64_t mylen = MIN(size, DMU_MAX_ACCESS / 2);
785 		int i;
786 
787 		/*
788 		 * NB: we could do this block-at-a-time, but it's nice
789 		 * to be reading in parallel.
790 		 */
791 		err = dmu_buf_hold_array_by_dnode(dn, offset, mylen,
792 		    TRUE, FTAG, &numbufs, &dbp, flags);
793 		if (err)
794 			break;
795 
796 		for (i = 0; i < numbufs; i++) {
797 			int tocpy;
798 			int bufoff;
799 			dmu_buf_t *db = dbp[i];
800 
801 			ASSERT(size > 0);
802 
803 			bufoff = offset - db->db_offset;
804 			tocpy = (int)MIN(db->db_size - bufoff, size);
805 
806 			bcopy((char *)db->db_data + bufoff, buf, tocpy);
807 
808 			offset += tocpy;
809 			size -= tocpy;
810 			buf = (char *)buf + tocpy;
811 		}
812 		dmu_buf_rele_array(dbp, numbufs, FTAG);
813 	}
814 	dnode_rele(dn, FTAG);
815 	return (err);
816 }
817 
818 void
dmu_write(objset_t * os,uint64_t object,uint64_t offset,uint64_t size,const void * buf,dmu_tx_t * tx)819 dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
820     const void *buf, dmu_tx_t *tx)
821 {
822 	dmu_buf_t **dbp;
823 	int numbufs, i;
824 
825 	if (size == 0)
826 		return;
827 
828 	VERIFY(0 == dmu_buf_hold_array(os, object, offset, size,
829 	    FALSE, FTAG, &numbufs, &dbp));
830 
831 	for (i = 0; i < numbufs; i++) {
832 		int tocpy;
833 		int bufoff;
834 		dmu_buf_t *db = dbp[i];
835 
836 		ASSERT(size > 0);
837 
838 		bufoff = offset - db->db_offset;
839 		tocpy = (int)MIN(db->db_size - bufoff, size);
840 
841 		ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
842 
843 		if (tocpy == db->db_size)
844 			dmu_buf_will_fill(db, tx);
845 		else
846 			dmu_buf_will_dirty(db, tx);
847 
848 		bcopy(buf, (char *)db->db_data + bufoff, tocpy);
849 
850 		if (tocpy == db->db_size)
851 			dmu_buf_fill_done(db, tx);
852 
853 		offset += tocpy;
854 		size -= tocpy;
855 		buf = (char *)buf + tocpy;
856 	}
857 	dmu_buf_rele_array(dbp, numbufs, FTAG);
858 }
859 
860 void
dmu_prealloc(objset_t * os,uint64_t object,uint64_t offset,uint64_t size,dmu_tx_t * tx)861 dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
862     dmu_tx_t *tx)
863 {
864 	dmu_buf_t **dbp;
865 	int numbufs, i;
866 
867 	if (size == 0)
868 		return;
869 
870 	VERIFY(0 == dmu_buf_hold_array(os, object, offset, size,
871 	    FALSE, FTAG, &numbufs, &dbp));
872 
873 	for (i = 0; i < numbufs; i++) {
874 		dmu_buf_t *db = dbp[i];
875 
876 		dmu_buf_will_not_fill(db, tx);
877 	}
878 	dmu_buf_rele_array(dbp, numbufs, FTAG);
879 }
880 
881 void
dmu_write_embedded(objset_t * os,uint64_t object,uint64_t offset,void * data,uint8_t etype,uint8_t comp,int uncompressed_size,int compressed_size,int byteorder,dmu_tx_t * tx)882 dmu_write_embedded(objset_t *os, uint64_t object, uint64_t offset,
883     void *data, uint8_t etype, uint8_t comp, int uncompressed_size,
884     int compressed_size, int byteorder, dmu_tx_t *tx)
885 {
886 	dmu_buf_t *db;
887 
888 	ASSERT3U(etype, <, NUM_BP_EMBEDDED_TYPES);
889 	ASSERT3U(comp, <, ZIO_COMPRESS_FUNCTIONS);
890 	VERIFY0(dmu_buf_hold_noread(os, object, offset,
891 	    FTAG, &db));
892 
893 	dmu_buf_write_embedded(db,
894 	    data, (bp_embedded_type_t)etype, (enum zio_compress)comp,
895 	    uncompressed_size, compressed_size, byteorder, tx);
896 
897 	dmu_buf_rele(db, FTAG);
898 }
899 
900 /*
901  * DMU support for xuio
902  */
903 kstat_t *xuio_ksp = NULL;
904 
905 int
dmu_xuio_init(xuio_t * xuio,int nblk)906 dmu_xuio_init(xuio_t *xuio, int nblk)
907 {
908 	dmu_xuio_t *priv;
909 	uio_t *uio = &xuio->xu_uio;
910 
911 	uio->uio_iovcnt = nblk;
912 	uio->uio_iov = kmem_zalloc(nblk * sizeof (iovec_t), KM_SLEEP);
913 
914 	priv = kmem_zalloc(sizeof (dmu_xuio_t), KM_SLEEP);
915 	priv->cnt = nblk;
916 	priv->bufs = kmem_zalloc(nblk * sizeof (arc_buf_t *), KM_SLEEP);
917 	priv->iovp = uio->uio_iov;
918 	XUIO_XUZC_PRIV(xuio) = priv;
919 
920 	if (XUIO_XUZC_RW(xuio) == UIO_READ)
921 		XUIOSTAT_INCR(xuiostat_onloan_rbuf, nblk);
922 	else
923 		XUIOSTAT_INCR(xuiostat_onloan_wbuf, nblk);
924 
925 	return (0);
926 }
927 
928 void
dmu_xuio_fini(xuio_t * xuio)929 dmu_xuio_fini(xuio_t *xuio)
930 {
931 	dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
932 	int nblk = priv->cnt;
933 
934 	kmem_free(priv->iovp, nblk * sizeof (iovec_t));
935 	kmem_free(priv->bufs, nblk * sizeof (arc_buf_t *));
936 	kmem_free(priv, sizeof (dmu_xuio_t));
937 
938 	if (XUIO_XUZC_RW(xuio) == UIO_READ)
939 		XUIOSTAT_INCR(xuiostat_onloan_rbuf, -nblk);
940 	else
941 		XUIOSTAT_INCR(xuiostat_onloan_wbuf, -nblk);
942 }
943 
944 /*
945  * Initialize iov[priv->next] and priv->bufs[priv->next] with { off, n, abuf }
946  * and increase priv->next by 1.
947  */
948 int
dmu_xuio_add(xuio_t * xuio,arc_buf_t * abuf,offset_t off,size_t n)949 dmu_xuio_add(xuio_t *xuio, arc_buf_t *abuf, offset_t off, size_t n)
950 {
951 	struct iovec *iov;
952 	uio_t *uio = &xuio->xu_uio;
953 	dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
954 	int i = priv->next++;
955 
956 	ASSERT(i < priv->cnt);
957 	ASSERT(off + n <= arc_buf_size(abuf));
958 	iov = uio->uio_iov + i;
959 	iov->iov_base = (char *)abuf->b_data + off;
960 	iov->iov_len = n;
961 	priv->bufs[i] = abuf;
962 	return (0);
963 }
964 
965 int
dmu_xuio_cnt(xuio_t * xuio)966 dmu_xuio_cnt(xuio_t *xuio)
967 {
968 	dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
969 	return (priv->cnt);
970 }
971 
972 arc_buf_t *
dmu_xuio_arcbuf(xuio_t * xuio,int i)973 dmu_xuio_arcbuf(xuio_t *xuio, int i)
974 {
975 	dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
976 
977 	ASSERT(i < priv->cnt);
978 	return (priv->bufs[i]);
979 }
980 
981 void
dmu_xuio_clear(xuio_t * xuio,int i)982 dmu_xuio_clear(xuio_t *xuio, int i)
983 {
984 	dmu_xuio_t *priv = XUIO_XUZC_PRIV(xuio);
985 
986 	ASSERT(i < priv->cnt);
987 	priv->bufs[i] = NULL;
988 }
989 
990 static void
xuio_stat_init(void)991 xuio_stat_init(void)
992 {
993 	xuio_ksp = kstat_create("zfs", 0, "xuio_stats", "misc",
994 	    KSTAT_TYPE_NAMED, sizeof (xuio_stats) / sizeof (kstat_named_t),
995 	    KSTAT_FLAG_VIRTUAL);
996 	if (xuio_ksp != NULL) {
997 		xuio_ksp->ks_data = &xuio_stats;
998 		kstat_install(xuio_ksp);
999 	}
1000 }
1001 
1002 static void
xuio_stat_fini(void)1003 xuio_stat_fini(void)
1004 {
1005 	if (xuio_ksp != NULL) {
1006 		kstat_delete(xuio_ksp);
1007 		xuio_ksp = NULL;
1008 	}
1009 }
1010 
1011 void
xuio_stat_wbuf_copied()1012 xuio_stat_wbuf_copied()
1013 {
1014 	XUIOSTAT_BUMP(xuiostat_wbuf_copied);
1015 }
1016 
1017 void
xuio_stat_wbuf_nocopy()1018 xuio_stat_wbuf_nocopy()
1019 {
1020 	XUIOSTAT_BUMP(xuiostat_wbuf_nocopy);
1021 }
1022 
1023 #ifdef _KERNEL
1024 static int
dmu_read_uio_dnode(dnode_t * dn,uio_t * uio,uint64_t size)1025 dmu_read_uio_dnode(dnode_t *dn, uio_t *uio, uint64_t size)
1026 {
1027 	dmu_buf_t **dbp;
1028 	int numbufs, i, err;
1029 	xuio_t *xuio = NULL;
1030 
1031 	/*
1032 	 * NB: we could do this block-at-a-time, but it's nice
1033 	 * to be reading in parallel.
1034 	 */
1035 	err = dmu_buf_hold_array_by_dnode(dn, uio->uio_loffset, size,
1036 	    TRUE, FTAG, &numbufs, &dbp, 0);
1037 	if (err)
1038 		return (err);
1039 
1040 	if (uio->uio_extflg == UIO_XUIO)
1041 		xuio = (xuio_t *)uio;
1042 
1043 	for (i = 0; i < numbufs; i++) {
1044 		int tocpy;
1045 		int bufoff;
1046 		dmu_buf_t *db = dbp[i];
1047 
1048 		ASSERT(size > 0);
1049 
1050 		bufoff = uio->uio_loffset - db->db_offset;
1051 		tocpy = (int)MIN(db->db_size - bufoff, size);
1052 
1053 		if (xuio) {
1054 			dmu_buf_impl_t *dbi = (dmu_buf_impl_t *)db;
1055 			arc_buf_t *dbuf_abuf = dbi->db_buf;
1056 			arc_buf_t *abuf = dbuf_loan_arcbuf(dbi);
1057 			err = dmu_xuio_add(xuio, abuf, bufoff, tocpy);
1058 			if (!err) {
1059 				uio->uio_resid -= tocpy;
1060 				uio->uio_loffset += tocpy;
1061 			}
1062 
1063 			if (abuf == dbuf_abuf)
1064 				XUIOSTAT_BUMP(xuiostat_rbuf_nocopy);
1065 			else
1066 				XUIOSTAT_BUMP(xuiostat_rbuf_copied);
1067 		} else {
1068 			err = uiomove((char *)db->db_data + bufoff, tocpy,
1069 			    UIO_READ, uio);
1070 		}
1071 		if (err)
1072 			break;
1073 
1074 		size -= tocpy;
1075 	}
1076 	dmu_buf_rele_array(dbp, numbufs, FTAG);
1077 
1078 	return (err);
1079 }
1080 
1081 /*
1082  * Read 'size' bytes into the uio buffer.
1083  * From object zdb->db_object.
1084  * Starting at offset uio->uio_loffset.
1085  *
1086  * If the caller already has a dbuf in the target object
1087  * (e.g. its bonus buffer), this routine is faster than dmu_read_uio(),
1088  * because we don't have to find the dnode_t for the object.
1089  */
1090 int
dmu_read_uio_dbuf(dmu_buf_t * zdb,uio_t * uio,uint64_t size)1091 dmu_read_uio_dbuf(dmu_buf_t *zdb, uio_t *uio, uint64_t size)
1092 {
1093 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)zdb;
1094 	dnode_t *dn;
1095 	int err;
1096 
1097 	if (size == 0)
1098 		return (0);
1099 
1100 	DB_DNODE_ENTER(db);
1101 	dn = DB_DNODE(db);
1102 	err = dmu_read_uio_dnode(dn, uio, size);
1103 	DB_DNODE_EXIT(db);
1104 
1105 	return (err);
1106 }
1107 
1108 /*
1109  * Read 'size' bytes into the uio buffer.
1110  * From the specified object
1111  * Starting at offset uio->uio_loffset.
1112  */
1113 int
dmu_read_uio(objset_t * os,uint64_t object,uio_t * uio,uint64_t size)1114 dmu_read_uio(objset_t *os, uint64_t object, uio_t *uio, uint64_t size)
1115 {
1116 	dnode_t *dn;
1117 	int err;
1118 
1119 	if (size == 0)
1120 		return (0);
1121 
1122 	err = dnode_hold(os, object, FTAG, &dn);
1123 	if (err)
1124 		return (err);
1125 
1126 	err = dmu_read_uio_dnode(dn, uio, size);
1127 
1128 	dnode_rele(dn, FTAG);
1129 
1130 	return (err);
1131 }
1132 
1133 static int
dmu_write_uio_dnode(dnode_t * dn,uio_t * uio,uint64_t size,dmu_tx_t * tx)1134 dmu_write_uio_dnode(dnode_t *dn, uio_t *uio, uint64_t size, dmu_tx_t *tx)
1135 {
1136 	dmu_buf_t **dbp;
1137 	int numbufs;
1138 	int err = 0;
1139 	int i;
1140 
1141 	err = dmu_buf_hold_array_by_dnode(dn, uio->uio_loffset, size,
1142 	    FALSE, FTAG, &numbufs, &dbp, DMU_READ_PREFETCH);
1143 	if (err)
1144 		return (err);
1145 
1146 	for (i = 0; i < numbufs; i++) {
1147 		int tocpy;
1148 		int bufoff;
1149 		dmu_buf_t *db = dbp[i];
1150 
1151 		ASSERT(size > 0);
1152 
1153 		bufoff = uio->uio_loffset - db->db_offset;
1154 		tocpy = (int)MIN(db->db_size - bufoff, size);
1155 
1156 		ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
1157 
1158 		if (tocpy == db->db_size)
1159 			dmu_buf_will_fill(db, tx);
1160 		else
1161 			dmu_buf_will_dirty(db, tx);
1162 
1163 		/*
1164 		 * XXX uiomove could block forever (eg. nfs-backed
1165 		 * pages).  There needs to be a uiolockdown() function
1166 		 * to lock the pages in memory, so that uiomove won't
1167 		 * block.
1168 		 */
1169 		err = uiomove((char *)db->db_data + bufoff, tocpy,
1170 		    UIO_WRITE, uio);
1171 
1172 		if (tocpy == db->db_size)
1173 			dmu_buf_fill_done(db, tx);
1174 
1175 		if (err)
1176 			break;
1177 
1178 		size -= tocpy;
1179 	}
1180 
1181 	dmu_buf_rele_array(dbp, numbufs, FTAG);
1182 	return (err);
1183 }
1184 
1185 /*
1186  * Write 'size' bytes from the uio buffer.
1187  * To object zdb->db_object.
1188  * Starting at offset uio->uio_loffset.
1189  *
1190  * If the caller already has a dbuf in the target object
1191  * (e.g. its bonus buffer), this routine is faster than dmu_write_uio(),
1192  * because we don't have to find the dnode_t for the object.
1193  */
1194 int
dmu_write_uio_dbuf(dmu_buf_t * zdb,uio_t * uio,uint64_t size,dmu_tx_t * tx)1195 dmu_write_uio_dbuf(dmu_buf_t *zdb, uio_t *uio, uint64_t size,
1196     dmu_tx_t *tx)
1197 {
1198 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)zdb;
1199 	dnode_t *dn;
1200 	int err;
1201 
1202 	if (size == 0)
1203 		return (0);
1204 
1205 	DB_DNODE_ENTER(db);
1206 	dn = DB_DNODE(db);
1207 	err = dmu_write_uio_dnode(dn, uio, size, tx);
1208 	DB_DNODE_EXIT(db);
1209 
1210 	return (err);
1211 }
1212 
1213 /*
1214  * Write 'size' bytes from the uio buffer.
1215  * To the specified object.
1216  * Starting at offset uio->uio_loffset.
1217  */
1218 int
dmu_write_uio(objset_t * os,uint64_t object,uio_t * uio,uint64_t size,dmu_tx_t * tx)1219 dmu_write_uio(objset_t *os, uint64_t object, uio_t *uio, uint64_t size,
1220     dmu_tx_t *tx)
1221 {
1222 	dnode_t *dn;
1223 	int err;
1224 
1225 	if (size == 0)
1226 		return (0);
1227 
1228 	err = dnode_hold(os, object, FTAG, &dn);
1229 	if (err)
1230 		return (err);
1231 
1232 	err = dmu_write_uio_dnode(dn, uio, size, tx);
1233 
1234 	dnode_rele(dn, FTAG);
1235 
1236 	return (err);
1237 }
1238 
1239 int
dmu_write_pages(objset_t * os,uint64_t object,uint64_t offset,uint64_t size,page_t * pp,dmu_tx_t * tx)1240 dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
1241     page_t *pp, dmu_tx_t *tx)
1242 {
1243 	dmu_buf_t **dbp;
1244 	int numbufs, i;
1245 	int err;
1246 
1247 	if (size == 0)
1248 		return (0);
1249 
1250 	err = dmu_buf_hold_array(os, object, offset, size,
1251 	    FALSE, FTAG, &numbufs, &dbp);
1252 	if (err)
1253 		return (err);
1254 
1255 	for (i = 0; i < numbufs; i++) {
1256 		int tocpy, copied, thiscpy;
1257 		int bufoff;
1258 		dmu_buf_t *db = dbp[i];
1259 		caddr_t va;
1260 
1261 		ASSERT(size > 0);
1262 		ASSERT3U(db->db_size, >=, PAGESIZE);
1263 
1264 		bufoff = offset - db->db_offset;
1265 		tocpy = (int)MIN(db->db_size - bufoff, size);
1266 
1267 		ASSERT(i == 0 || i == numbufs-1 || tocpy == db->db_size);
1268 
1269 		if (tocpy == db->db_size)
1270 			dmu_buf_will_fill(db, tx);
1271 		else
1272 			dmu_buf_will_dirty(db, tx);
1273 
1274 		for (copied = 0; copied < tocpy; copied += PAGESIZE) {
1275 			ASSERT3U(pp->p_offset, ==, db->db_offset + bufoff);
1276 			thiscpy = MIN(PAGESIZE, tocpy - copied);
1277 			va = zfs_map_page(pp, S_READ);
1278 			bcopy(va, (char *)db->db_data + bufoff, thiscpy);
1279 			zfs_unmap_page(pp, va);
1280 			pp = pp->p_next;
1281 			bufoff += PAGESIZE;
1282 		}
1283 
1284 		if (tocpy == db->db_size)
1285 			dmu_buf_fill_done(db, tx);
1286 
1287 		offset += tocpy;
1288 		size -= tocpy;
1289 	}
1290 	dmu_buf_rele_array(dbp, numbufs, FTAG);
1291 	return (err);
1292 }
1293 #endif
1294 
1295 /*
1296  * Allocate a loaned anonymous arc buffer.
1297  */
1298 arc_buf_t *
dmu_request_arcbuf(dmu_buf_t * handle,int size)1299 dmu_request_arcbuf(dmu_buf_t *handle, int size)
1300 {
1301 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)handle;
1302 
1303 	return (arc_loan_buf(db->db_objset->os_spa, size));
1304 }
1305 
1306 /*
1307  * Free a loaned arc buffer.
1308  */
1309 void
dmu_return_arcbuf(arc_buf_t * buf)1310 dmu_return_arcbuf(arc_buf_t *buf)
1311 {
1312 	arc_return_buf(buf, FTAG);
1313 	VERIFY(arc_buf_remove_ref(buf, FTAG));
1314 }
1315 
1316 /*
1317  * When possible directly assign passed loaned arc buffer to a dbuf.
1318  * If this is not possible copy the contents of passed arc buf via
1319  * dmu_write().
1320  */
1321 void
dmu_assign_arcbuf(dmu_buf_t * handle,uint64_t offset,arc_buf_t * buf,dmu_tx_t * tx)1322 dmu_assign_arcbuf(dmu_buf_t *handle, uint64_t offset, arc_buf_t *buf,
1323     dmu_tx_t *tx)
1324 {
1325 	dmu_buf_impl_t *dbuf = (dmu_buf_impl_t *)handle;
1326 	dnode_t *dn;
1327 	dmu_buf_impl_t *db;
1328 	uint32_t blksz = (uint32_t)arc_buf_size(buf);
1329 	uint64_t blkid;
1330 
1331 	DB_DNODE_ENTER(dbuf);
1332 	dn = DB_DNODE(dbuf);
1333 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
1334 	blkid = dbuf_whichblock(dn, 0, offset);
1335 	VERIFY((db = dbuf_hold(dn, blkid, FTAG)) != NULL);
1336 	rw_exit(&dn->dn_struct_rwlock);
1337 	DB_DNODE_EXIT(dbuf);
1338 
1339 	/*
1340 	 * We can only assign if the offset is aligned, the arc buf is the
1341 	 * same size as the dbuf, and the dbuf is not metadata.  It
1342 	 * can't be metadata because the loaned arc buf comes from the
1343 	 * user-data kmem arena.
1344 	 */
1345 	if (offset == db->db.db_offset && blksz == db->db.db_size &&
1346 	    DBUF_GET_BUFC_TYPE(db) == ARC_BUFC_DATA) {
1347 		dbuf_assign_arcbuf(db, buf, tx);
1348 		dbuf_rele(db, FTAG);
1349 	} else {
1350 		objset_t *os;
1351 		uint64_t object;
1352 
1353 		DB_DNODE_ENTER(dbuf);
1354 		dn = DB_DNODE(dbuf);
1355 		os = dn->dn_objset;
1356 		object = dn->dn_object;
1357 		DB_DNODE_EXIT(dbuf);
1358 
1359 		dbuf_rele(db, FTAG);
1360 		dmu_write(os, object, offset, blksz, buf->b_data, tx);
1361 		dmu_return_arcbuf(buf);
1362 		XUIOSTAT_BUMP(xuiostat_wbuf_copied);
1363 	}
1364 }
1365 
1366 typedef struct {
1367 	dbuf_dirty_record_t	*dsa_dr;
1368 	dmu_sync_cb_t		*dsa_done;
1369 	zgd_t			*dsa_zgd;
1370 	dmu_tx_t		*dsa_tx;
1371 } dmu_sync_arg_t;
1372 
1373 /* ARGSUSED */
1374 static void
dmu_sync_ready(zio_t * zio,arc_buf_t * buf,void * varg)1375 dmu_sync_ready(zio_t *zio, arc_buf_t *buf, void *varg)
1376 {
1377 	dmu_sync_arg_t *dsa = varg;
1378 	dmu_buf_t *db = dsa->dsa_zgd->zgd_db;
1379 	blkptr_t *bp = zio->io_bp;
1380 
1381 	if (zio->io_error == 0) {
1382 		if (BP_IS_HOLE(bp)) {
1383 			/*
1384 			 * A block of zeros may compress to a hole, but the
1385 			 * block size still needs to be known for replay.
1386 			 */
1387 			BP_SET_LSIZE(bp, db->db_size);
1388 		} else if (!BP_IS_EMBEDDED(bp)) {
1389 			ASSERT(BP_GET_LEVEL(bp) == 0);
1390 			bp->blk_fill = 1;
1391 		}
1392 	}
1393 }
1394 
1395 static void
dmu_sync_late_arrival_ready(zio_t * zio)1396 dmu_sync_late_arrival_ready(zio_t *zio)
1397 {
1398 	dmu_sync_ready(zio, NULL, zio->io_private);
1399 }
1400 
1401 /* ARGSUSED */
1402 static void
dmu_sync_done(zio_t * zio,arc_buf_t * buf,void * varg)1403 dmu_sync_done(zio_t *zio, arc_buf_t *buf, void *varg)
1404 {
1405 	dmu_sync_arg_t *dsa = varg;
1406 	dbuf_dirty_record_t *dr = dsa->dsa_dr;
1407 	dmu_buf_impl_t *db = dr->dr_dbuf;
1408 
1409 	mutex_enter(&db->db_mtx);
1410 	ASSERT(dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC);
1411 	if (zio->io_error == 0) {
1412 		dr->dt.dl.dr_nopwrite = !!(zio->io_flags & ZIO_FLAG_NOPWRITE);
1413 		if (dr->dt.dl.dr_nopwrite) {
1414 			blkptr_t *bp = zio->io_bp;
1415 			blkptr_t *bp_orig = &zio->io_bp_orig;
1416 			uint8_t chksum = BP_GET_CHECKSUM(bp_orig);
1417 
1418 			ASSERT(BP_EQUAL(bp, bp_orig));
1419 			ASSERT(zio->io_prop.zp_compress != ZIO_COMPRESS_OFF);
1420 			ASSERT(zio_checksum_table[chksum].ci_dedup);
1421 		}
1422 		dr->dt.dl.dr_overridden_by = *zio->io_bp;
1423 		dr->dt.dl.dr_override_state = DR_OVERRIDDEN;
1424 		dr->dt.dl.dr_copies = zio->io_prop.zp_copies;
1425 
1426 		/*
1427 		 * Old style holes are filled with all zeros, whereas
1428 		 * new-style holes maintain their lsize, type, level,
1429 		 * and birth time (see zio_write_compress). While we
1430 		 * need to reset the BP_SET_LSIZE() call that happened
1431 		 * in dmu_sync_ready for old style holes, we do *not*
1432 		 * want to wipe out the information contained in new
1433 		 * style holes. Thus, only zero out the block pointer if
1434 		 * it's an old style hole.
1435 		 */
1436 		if (BP_IS_HOLE(&dr->dt.dl.dr_overridden_by) &&
1437 		    dr->dt.dl.dr_overridden_by.blk_birth == 0)
1438 			BP_ZERO(&dr->dt.dl.dr_overridden_by);
1439 	} else {
1440 		dr->dt.dl.dr_override_state = DR_NOT_OVERRIDDEN;
1441 	}
1442 	cv_broadcast(&db->db_changed);
1443 	mutex_exit(&db->db_mtx);
1444 
1445 	dsa->dsa_done(dsa->dsa_zgd, zio->io_error);
1446 
1447 	kmem_free(dsa, sizeof (*dsa));
1448 }
1449 
1450 static void
dmu_sync_late_arrival_done(zio_t * zio)1451 dmu_sync_late_arrival_done(zio_t *zio)
1452 {
1453 	blkptr_t *bp = zio->io_bp;
1454 	dmu_sync_arg_t *dsa = zio->io_private;
1455 	blkptr_t *bp_orig = &zio->io_bp_orig;
1456 
1457 	if (zio->io_error == 0 && !BP_IS_HOLE(bp)) {
1458 		/*
1459 		 * If we didn't allocate a new block (i.e. ZIO_FLAG_NOPWRITE)
1460 		 * then there is nothing to do here. Otherwise, free the
1461 		 * newly allocated block in this txg.
1462 		 */
1463 		if (zio->io_flags & ZIO_FLAG_NOPWRITE) {
1464 			ASSERT(BP_EQUAL(bp, bp_orig));
1465 		} else {
1466 			ASSERT(BP_IS_HOLE(bp_orig) || !BP_EQUAL(bp, bp_orig));
1467 			ASSERT(zio->io_bp->blk_birth == zio->io_txg);
1468 			ASSERT(zio->io_txg > spa_syncing_txg(zio->io_spa));
1469 			zio_free(zio->io_spa, zio->io_txg, zio->io_bp);
1470 		}
1471 	}
1472 
1473 	dmu_tx_commit(dsa->dsa_tx);
1474 
1475 	dsa->dsa_done(dsa->dsa_zgd, zio->io_error);
1476 
1477 	kmem_free(dsa, sizeof (*dsa));
1478 }
1479 
1480 static int
dmu_sync_late_arrival(zio_t * pio,objset_t * os,dmu_sync_cb_t * done,zgd_t * zgd,zio_prop_t * zp,zbookmark_phys_t * zb)1481 dmu_sync_late_arrival(zio_t *pio, objset_t *os, dmu_sync_cb_t *done, zgd_t *zgd,
1482     zio_prop_t *zp, zbookmark_phys_t *zb)
1483 {
1484 	dmu_sync_arg_t *dsa;
1485 	dmu_tx_t *tx;
1486 
1487 	tx = dmu_tx_create(os);
1488 	dmu_tx_hold_space(tx, zgd->zgd_db->db_size);
1489 	if (dmu_tx_assign(tx, TXG_WAIT) != 0) {
1490 		dmu_tx_abort(tx);
1491 		/* Make zl_get_data do txg_waited_synced() */
1492 		return (SET_ERROR(EIO));
1493 	}
1494 
1495 	dsa = kmem_alloc(sizeof (dmu_sync_arg_t), KM_SLEEP);
1496 	dsa->dsa_dr = NULL;
1497 	dsa->dsa_done = done;
1498 	dsa->dsa_zgd = zgd;
1499 	dsa->dsa_tx = tx;
1500 
1501 	zio_nowait(zio_write(pio, os->os_spa, dmu_tx_get_txg(tx), zgd->zgd_bp,
1502 	    zgd->zgd_db->db_data, zgd->zgd_db->db_size, zp,
1503 	    dmu_sync_late_arrival_ready, NULL, dmu_sync_late_arrival_done, dsa,
1504 	    ZIO_PRIORITY_SYNC_WRITE, ZIO_FLAG_CANFAIL, zb));
1505 
1506 	return (0);
1507 }
1508 
1509 /*
1510  * Intent log support: sync the block associated with db to disk.
1511  * N.B. and XXX: the caller is responsible for making sure that the
1512  * data isn't changing while dmu_sync() is writing it.
1513  *
1514  * Return values:
1515  *
1516  *	EEXIST: this txg has already been synced, so there's nothing to do.
1517  *		The caller should not log the write.
1518  *
1519  *	ENOENT: the block was dbuf_free_range()'d, so there's nothing to do.
1520  *		The caller should not log the write.
1521  *
1522  *	EALREADY: this block is already in the process of being synced.
1523  *		The caller should track its progress (somehow).
1524  *
1525  *	EIO: could not do the I/O.
1526  *		The caller should do a txg_wait_synced().
1527  *
1528  *	0: the I/O has been initiated.
1529  *		The caller should log this blkptr in the done callback.
1530  *		It is possible that the I/O will fail, in which case
1531  *		the error will be reported to the done callback and
1532  *		propagated to pio from zio_done().
1533  */
1534 int
dmu_sync(zio_t * pio,uint64_t txg,dmu_sync_cb_t * done,zgd_t * zgd)1535 dmu_sync(zio_t *pio, uint64_t txg, dmu_sync_cb_t *done, zgd_t *zgd)
1536 {
1537 	blkptr_t *bp = zgd->zgd_bp;
1538 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)zgd->zgd_db;
1539 	objset_t *os = db->db_objset;
1540 	dsl_dataset_t *ds = os->os_dsl_dataset;
1541 	dbuf_dirty_record_t *dr;
1542 	dmu_sync_arg_t *dsa;
1543 	zbookmark_phys_t zb;
1544 	zio_prop_t zp;
1545 	dnode_t *dn;
1546 
1547 	ASSERT(pio != NULL);
1548 	ASSERT(txg != 0);
1549 
1550 	SET_BOOKMARK(&zb, ds->ds_object,
1551 	    db->db.db_object, db->db_level, db->db_blkid);
1552 
1553 	DB_DNODE_ENTER(db);
1554 	dn = DB_DNODE(db);
1555 	dmu_write_policy(os, dn, db->db_level, WP_DMU_SYNC, &zp);
1556 	DB_DNODE_EXIT(db);
1557 
1558 	/*
1559 	 * If we're frozen (running ziltest), we always need to generate a bp.
1560 	 */
1561 	if (txg > spa_freeze_txg(os->os_spa))
1562 		return (dmu_sync_late_arrival(pio, os, done, zgd, &zp, &zb));
1563 
1564 	/*
1565 	 * Grabbing db_mtx now provides a barrier between dbuf_sync_leaf()
1566 	 * and us.  If we determine that this txg is not yet syncing,
1567 	 * but it begins to sync a moment later, that's OK because the
1568 	 * sync thread will block in dbuf_sync_leaf() until we drop db_mtx.
1569 	 */
1570 	mutex_enter(&db->db_mtx);
1571 
1572 	if (txg <= spa_last_synced_txg(os->os_spa)) {
1573 		/*
1574 		 * This txg has already synced.  There's nothing to do.
1575 		 */
1576 		mutex_exit(&db->db_mtx);
1577 		return (SET_ERROR(EEXIST));
1578 	}
1579 
1580 	if (txg <= spa_syncing_txg(os->os_spa)) {
1581 		/*
1582 		 * This txg is currently syncing, so we can't mess with
1583 		 * the dirty record anymore; just write a new log block.
1584 		 */
1585 		mutex_exit(&db->db_mtx);
1586 		return (dmu_sync_late_arrival(pio, os, done, zgd, &zp, &zb));
1587 	}
1588 
1589 	dr = db->db_last_dirty;
1590 	while (dr && dr->dr_txg != txg)
1591 		dr = dr->dr_next;
1592 
1593 	if (dr == NULL) {
1594 		/*
1595 		 * There's no dr for this dbuf, so it must have been freed.
1596 		 * There's no need to log writes to freed blocks, so we're done.
1597 		 */
1598 		mutex_exit(&db->db_mtx);
1599 		return (SET_ERROR(ENOENT));
1600 	}
1601 
1602 	ASSERT(dr->dr_next == NULL || dr->dr_next->dr_txg < txg);
1603 
1604 	/*
1605 	 * Assume the on-disk data is X, the current syncing data (in
1606 	 * txg - 1) is Y, and the current in-memory data is Z (currently
1607 	 * in dmu_sync).
1608 	 *
1609 	 * We usually want to perform a nopwrite if X and Z are the
1610 	 * same.  However, if Y is different (i.e. the BP is going to
1611 	 * change before this write takes effect), then a nopwrite will
1612 	 * be incorrect - we would override with X, which could have
1613 	 * been freed when Y was written.
1614 	 *
1615 	 * (Note that this is not a concern when we are nop-writing from
1616 	 * syncing context, because X and Y must be identical, because
1617 	 * all previous txgs have been synced.)
1618 	 *
1619 	 * Therefore, we disable nopwrite if the current BP could change
1620 	 * before this TXG.  There are two ways it could change: by
1621 	 * being dirty (dr_next is non-NULL), or by being freed
1622 	 * (dnode_block_freed()).  This behavior is verified by
1623 	 * zio_done(), which VERIFYs that the override BP is identical
1624 	 * to the on-disk BP.
1625 	 */
1626 	DB_DNODE_ENTER(db);
1627 	dn = DB_DNODE(db);
1628 	if (dr->dr_next != NULL || dnode_block_freed(dn, db->db_blkid))
1629 		zp.zp_nopwrite = B_FALSE;
1630 	DB_DNODE_EXIT(db);
1631 
1632 	ASSERT(dr->dr_txg == txg);
1633 	if (dr->dt.dl.dr_override_state == DR_IN_DMU_SYNC ||
1634 	    dr->dt.dl.dr_override_state == DR_OVERRIDDEN) {
1635 		/*
1636 		 * We have already issued a sync write for this buffer,
1637 		 * or this buffer has already been synced.  It could not
1638 		 * have been dirtied since, or we would have cleared the state.
1639 		 */
1640 		mutex_exit(&db->db_mtx);
1641 		return (SET_ERROR(EALREADY));
1642 	}
1643 
1644 	ASSERT(dr->dt.dl.dr_override_state == DR_NOT_OVERRIDDEN);
1645 	dr->dt.dl.dr_override_state = DR_IN_DMU_SYNC;
1646 	mutex_exit(&db->db_mtx);
1647 
1648 	dsa = kmem_alloc(sizeof (dmu_sync_arg_t), KM_SLEEP);
1649 	dsa->dsa_dr = dr;
1650 	dsa->dsa_done = done;
1651 	dsa->dsa_zgd = zgd;
1652 	dsa->dsa_tx = NULL;
1653 
1654 	zio_nowait(arc_write(pio, os->os_spa, txg,
1655 	    bp, dr->dt.dl.dr_data, DBUF_IS_L2CACHEABLE(db),
1656 	    DBUF_IS_L2COMPRESSIBLE(db), &zp, dmu_sync_ready,
1657 	    NULL, dmu_sync_done, dsa, ZIO_PRIORITY_SYNC_WRITE,
1658 	    ZIO_FLAG_CANFAIL, &zb));
1659 
1660 	return (0);
1661 }
1662 
1663 int
dmu_object_set_blocksize(objset_t * os,uint64_t object,uint64_t size,int ibs,dmu_tx_t * tx)1664 dmu_object_set_blocksize(objset_t *os, uint64_t object, uint64_t size, int ibs,
1665 	dmu_tx_t *tx)
1666 {
1667 	dnode_t *dn;
1668 	int err;
1669 
1670 	err = dnode_hold(os, object, FTAG, &dn);
1671 	if (err)
1672 		return (err);
1673 	err = dnode_set_blksz(dn, size, ibs, tx);
1674 	dnode_rele(dn, FTAG);
1675 	return (err);
1676 }
1677 
1678 void
dmu_object_set_checksum(objset_t * os,uint64_t object,uint8_t checksum,dmu_tx_t * tx)1679 dmu_object_set_checksum(objset_t *os, uint64_t object, uint8_t checksum,
1680 	dmu_tx_t *tx)
1681 {
1682 	dnode_t *dn;
1683 
1684 	/*
1685 	 * Send streams include each object's checksum function.  This
1686 	 * check ensures that the receiving system can understand the
1687 	 * checksum function transmitted.
1688 	 */
1689 	ASSERT3U(checksum, <, ZIO_CHECKSUM_LEGACY_FUNCTIONS);
1690 
1691 	VERIFY0(dnode_hold(os, object, FTAG, &dn));
1692 	ASSERT3U(checksum, <, ZIO_CHECKSUM_FUNCTIONS);
1693 	dn->dn_checksum = checksum;
1694 	dnode_setdirty(dn, tx);
1695 	dnode_rele(dn, FTAG);
1696 }
1697 
1698 void
dmu_object_set_compress(objset_t * os,uint64_t object,uint8_t compress,dmu_tx_t * tx)1699 dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
1700 	dmu_tx_t *tx)
1701 {
1702 	dnode_t *dn;
1703 
1704 	/*
1705 	 * Send streams include each object's compression function.  This
1706 	 * check ensures that the receiving system can understand the
1707 	 * compression function transmitted.
1708 	 */
1709 	ASSERT3U(compress, <, ZIO_COMPRESS_LEGACY_FUNCTIONS);
1710 
1711 	VERIFY0(dnode_hold(os, object, FTAG, &dn));
1712 	dn->dn_compress = compress;
1713 	dnode_setdirty(dn, tx);
1714 	dnode_rele(dn, FTAG);
1715 }
1716 
1717 int zfs_mdcomp_disable = 0;
1718 
1719 /*
1720  * When the "redundant_metadata" property is set to "most", only indirect
1721  * blocks of this level and higher will have an additional ditto block.
1722  */
1723 int zfs_redundant_metadata_most_ditto_level = 2;
1724 
1725 void
dmu_write_policy(objset_t * os,dnode_t * dn,int level,int wp,zio_prop_t * zp)1726 dmu_write_policy(objset_t *os, dnode_t *dn, int level, int wp, zio_prop_t *zp)
1727 {
1728 	dmu_object_type_t type = dn ? dn->dn_type : DMU_OT_OBJSET;
1729 	boolean_t ismd = (level > 0 || DMU_OT_IS_METADATA(type) ||
1730 	    (wp & WP_SPILL));
1731 	enum zio_checksum checksum = os->os_checksum;
1732 	enum zio_compress compress = os->os_compress;
1733 	enum zio_checksum dedup_checksum = os->os_dedup_checksum;
1734 	boolean_t dedup = B_FALSE;
1735 	boolean_t nopwrite = B_FALSE;
1736 	boolean_t dedup_verify = os->os_dedup_verify;
1737 	int copies = os->os_copies;
1738 
1739 	/*
1740 	 * We maintain different write policies for each of the following
1741 	 * types of data:
1742 	 *	 1. metadata
1743 	 *	 2. preallocated blocks (i.e. level-0 blocks of a dump device)
1744 	 *	 3. all other level 0 blocks
1745 	 */
1746 	if (ismd) {
1747 		if (zfs_mdcomp_disable) {
1748 			compress = ZIO_COMPRESS_EMPTY;
1749 		} else {
1750 			/*
1751 			 * XXX -- we should design a compression algorithm
1752 			 * that specializes in arrays of bps.
1753 			 */
1754 			compress = zio_compress_select(os->os_spa,
1755 			    ZIO_COMPRESS_ON, ZIO_COMPRESS_ON);
1756 		}
1757 
1758 		/*
1759 		 * Metadata always gets checksummed.  If the data
1760 		 * checksum is multi-bit correctable, and it's not a
1761 		 * ZBT-style checksum, then it's suitable for metadata
1762 		 * as well.  Otherwise, the metadata checksum defaults
1763 		 * to fletcher4.
1764 		 */
1765 		if (zio_checksum_table[checksum].ci_correctable < 1 ||
1766 		    zio_checksum_table[checksum].ci_eck)
1767 			checksum = ZIO_CHECKSUM_FLETCHER_4;
1768 
1769 		if (os->os_redundant_metadata == ZFS_REDUNDANT_METADATA_ALL ||
1770 		    (os->os_redundant_metadata ==
1771 		    ZFS_REDUNDANT_METADATA_MOST &&
1772 		    (level >= zfs_redundant_metadata_most_ditto_level ||
1773 		    DMU_OT_IS_METADATA(type) || (wp & WP_SPILL))))
1774 			copies++;
1775 	} else if (wp & WP_NOFILL) {
1776 		ASSERT(level == 0);
1777 
1778 		/*
1779 		 * If we're writing preallocated blocks, we aren't actually
1780 		 * writing them so don't set any policy properties.  These
1781 		 * blocks are currently only used by an external subsystem
1782 		 * outside of zfs (i.e. dump) and not written by the zio
1783 		 * pipeline.
1784 		 */
1785 		compress = ZIO_COMPRESS_OFF;
1786 		checksum = ZIO_CHECKSUM_NOPARITY;
1787 	} else {
1788 		compress = zio_compress_select(os->os_spa, dn->dn_compress,
1789 		    compress);
1790 
1791 		checksum = (dedup_checksum == ZIO_CHECKSUM_OFF) ?
1792 		    zio_checksum_select(dn->dn_checksum, checksum) :
1793 		    dedup_checksum;
1794 
1795 		/*
1796 		 * Determine dedup setting.  If we are in dmu_sync(),
1797 		 * we won't actually dedup now because that's all
1798 		 * done in syncing context; but we do want to use the
1799 		 * dedup checkum.  If the checksum is not strong
1800 		 * enough to ensure unique signatures, force
1801 		 * dedup_verify.
1802 		 */
1803 		if (dedup_checksum != ZIO_CHECKSUM_OFF) {
1804 			dedup = (wp & WP_DMU_SYNC) ? B_FALSE : B_TRUE;
1805 			if (!zio_checksum_table[checksum].ci_dedup)
1806 				dedup_verify = B_TRUE;
1807 		}
1808 
1809 		/*
1810 		 * Enable nopwrite if we have a cryptographically secure
1811 		 * checksum that has no known collisions (i.e. SHA-256)
1812 		 * and compression is enabled.  We don't enable nopwrite if
1813 		 * dedup is enabled as the two features are mutually exclusive.
1814 		 */
1815 		nopwrite = (!dedup && zio_checksum_table[checksum].ci_dedup &&
1816 		    compress != ZIO_COMPRESS_OFF && zfs_nopwrite_enabled);
1817 	}
1818 
1819 	zp->zp_checksum = checksum;
1820 	zp->zp_compress = compress;
1821 	zp->zp_type = (wp & WP_SPILL) ? dn->dn_bonustype : type;
1822 	zp->zp_level = level;
1823 	zp->zp_copies = MIN(copies, spa_max_replication(os->os_spa));
1824 	zp->zp_dedup = dedup;
1825 	zp->zp_dedup_verify = dedup && dedup_verify;
1826 	zp->zp_nopwrite = nopwrite;
1827 }
1828 
1829 int
dmu_offset_next(objset_t * os,uint64_t object,boolean_t hole,uint64_t * off)1830 dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole, uint64_t *off)
1831 {
1832 	dnode_t *dn;
1833 	int err;
1834 
1835 	/*
1836 	 * Sync any current changes before
1837 	 * we go trundling through the block pointers.
1838 	 */
1839 	err = dmu_object_wait_synced(os, object);
1840 	if (err) {
1841 		return (err);
1842 	}
1843 
1844 	err = dnode_hold(os, object, FTAG, &dn);
1845 	if (err) {
1846 		return (err);
1847 	}
1848 
1849 	err = dnode_next_offset(dn, (hole ? DNODE_FIND_HOLE : 0), off, 1, 1, 0);
1850 	dnode_rele(dn, FTAG);
1851 
1852 	return (err);
1853 }
1854 
1855 /*
1856  * Given the ZFS object, if it contains any dirty nodes
1857  * this function flushes all dirty blocks to disk. This
1858  * ensures the DMU object info is updated. A more efficient
1859  * future version might just find the TXG with the maximum
1860  * ID and wait for that to be synced.
1861  */
1862 int
dmu_object_wait_synced(objset_t * os,uint64_t object)1863 dmu_object_wait_synced(objset_t *os, uint64_t object) {
1864 	dnode_t *dn;
1865 	int error, i;
1866 
1867 	error = dnode_hold(os, object, FTAG, &dn);
1868 	if (error) {
1869 		return (error);
1870 	}
1871 
1872 	for (i = 0; i < TXG_SIZE; i++) {
1873 		if (list_link_active(&dn->dn_dirty_link[i])) {
1874 			break;
1875 		}
1876 	}
1877 	dnode_rele(dn, FTAG);
1878 	if (i != TXG_SIZE) {
1879 		txg_wait_synced(dmu_objset_pool(os), 0);
1880 	}
1881 
1882 	return (0);
1883 }
1884 
1885 void
dmu_object_info_from_dnode(dnode_t * dn,dmu_object_info_t * doi)1886 dmu_object_info_from_dnode(dnode_t *dn, dmu_object_info_t *doi)
1887 {
1888 	dnode_phys_t *dnp;
1889 
1890 	rw_enter(&dn->dn_struct_rwlock, RW_READER);
1891 	mutex_enter(&dn->dn_mtx);
1892 
1893 	dnp = dn->dn_phys;
1894 
1895 	doi->doi_data_block_size = dn->dn_datablksz;
1896 	doi->doi_metadata_block_size = dn->dn_indblkshift ?
1897 	    1ULL << dn->dn_indblkshift : 0;
1898 	doi->doi_type = dn->dn_type;
1899 	doi->doi_bonus_type = dn->dn_bonustype;
1900 	doi->doi_bonus_size = dn->dn_bonuslen;
1901 	doi->doi_indirection = dn->dn_nlevels;
1902 	doi->doi_checksum = dn->dn_checksum;
1903 	doi->doi_compress = dn->dn_compress;
1904 	doi->doi_nblkptr = dn->dn_nblkptr;
1905 	doi->doi_physical_blocks_512 = (DN_USED_BYTES(dnp) + 256) >> 9;
1906 	doi->doi_max_offset = (dn->dn_maxblkid + 1) * dn->dn_datablksz;
1907 	doi->doi_fill_count = 0;
1908 	for (int i = 0; i < dnp->dn_nblkptr; i++)
1909 		doi->doi_fill_count += BP_GET_FILL(&dnp->dn_blkptr[i]);
1910 
1911 	mutex_exit(&dn->dn_mtx);
1912 	rw_exit(&dn->dn_struct_rwlock);
1913 }
1914 
1915 /*
1916  * Get information on a DMU object.
1917  * If doi is NULL, just indicates whether the object exists.
1918  */
1919 int
dmu_object_info(objset_t * os,uint64_t object,dmu_object_info_t * doi)1920 dmu_object_info(objset_t *os, uint64_t object, dmu_object_info_t *doi)
1921 {
1922 	dnode_t *dn;
1923 	int err = dnode_hold(os, object, FTAG, &dn);
1924 
1925 	if (err)
1926 		return (err);
1927 
1928 	if (doi != NULL)
1929 		dmu_object_info_from_dnode(dn, doi);
1930 
1931 	dnode_rele(dn, FTAG);
1932 	return (0);
1933 }
1934 
1935 /*
1936  * As above, but faster; can be used when you have a held dbuf in hand.
1937  */
1938 void
dmu_object_info_from_db(dmu_buf_t * db_fake,dmu_object_info_t * doi)1939 dmu_object_info_from_db(dmu_buf_t *db_fake, dmu_object_info_t *doi)
1940 {
1941 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1942 
1943 	DB_DNODE_ENTER(db);
1944 	dmu_object_info_from_dnode(DB_DNODE(db), doi);
1945 	DB_DNODE_EXIT(db);
1946 }
1947 
1948 /*
1949  * Faster still when you only care about the size.
1950  * This is specifically optimized for zfs_getattr().
1951  */
1952 void
dmu_object_size_from_db(dmu_buf_t * db_fake,uint32_t * blksize,u_longlong_t * nblk512)1953 dmu_object_size_from_db(dmu_buf_t *db_fake, uint32_t *blksize,
1954     u_longlong_t *nblk512)
1955 {
1956 	dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
1957 	dnode_t *dn;
1958 
1959 	DB_DNODE_ENTER(db);
1960 	dn = DB_DNODE(db);
1961 
1962 	*blksize = dn->dn_datablksz;
1963 	/* add 1 for dnode space */
1964 	*nblk512 = ((DN_USED_BYTES(dn->dn_phys) + SPA_MINBLOCKSIZE/2) >>
1965 	    SPA_MINBLOCKSHIFT) + 1;
1966 	DB_DNODE_EXIT(db);
1967 }
1968 
1969 void
byteswap_uint64_array(void * vbuf,size_t size)1970 byteswap_uint64_array(void *vbuf, size_t size)
1971 {
1972 	uint64_t *buf = vbuf;
1973 	size_t count = size >> 3;
1974 	int i;
1975 
1976 	ASSERT((size & 7) == 0);
1977 
1978 	for (i = 0; i < count; i++)
1979 		buf[i] = BSWAP_64(buf[i]);
1980 }
1981 
1982 void
byteswap_uint32_array(void * vbuf,size_t size)1983 byteswap_uint32_array(void *vbuf, size_t size)
1984 {
1985 	uint32_t *buf = vbuf;
1986 	size_t count = size >> 2;
1987 	int i;
1988 
1989 	ASSERT((size & 3) == 0);
1990 
1991 	for (i = 0; i < count; i++)
1992 		buf[i] = BSWAP_32(buf[i]);
1993 }
1994 
1995 void
byteswap_uint16_array(void * vbuf,size_t size)1996 byteswap_uint16_array(void *vbuf, size_t size)
1997 {
1998 	uint16_t *buf = vbuf;
1999 	size_t count = size >> 1;
2000 	int i;
2001 
2002 	ASSERT((size & 1) == 0);
2003 
2004 	for (i = 0; i < count; i++)
2005 		buf[i] = BSWAP_16(buf[i]);
2006 }
2007 
2008 /* ARGSUSED */
2009 void
byteswap_uint8_array(void * vbuf,size_t size)2010 byteswap_uint8_array(void *vbuf, size_t size)
2011 {
2012 }
2013 
2014 void
dmu_init(void)2015 dmu_init(void)
2016 {
2017 	zfs_dbgmsg_init();
2018 	sa_cache_init();
2019 	xuio_stat_init();
2020 	dmu_objset_init();
2021 	dnode_init();
2022 	dbuf_init();
2023 	zfetch_init();
2024 	l2arc_init();
2025 	arc_init();
2026 }
2027 
2028 void
dmu_fini(void)2029 dmu_fini(void)
2030 {
2031 	arc_fini(); /* arc depends on l2arc, so arc must go first */
2032 	l2arc_fini();
2033 	zfetch_fini();
2034 	dbuf_fini();
2035 	dnode_fini();
2036 	dmu_objset_fini();
2037 	xuio_stat_fini();
2038 	sa_cache_fini();
2039 	zfs_dbgmsg_fini();
2040 }
2041