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) 2012, 2017 by Delphix. All rights reserved.
24 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
25 * Copyright (c) 2014 Integros [integros.com]
26 * Copyright 2017 RackTop Systems.
27 */
28
29 #include <sys/zfs_context.h>
30 #include <sys/dbuf.h>
31 #include <sys/dnode.h>
32 #include <sys/dmu.h>
33 #include <sys/dmu_impl.h>
34 #include <sys/dmu_tx.h>
35 #include <sys/dmu_objset.h>
36 #include <sys/dsl_dir.h>
37 #include <sys/dsl_dataset.h>
38 #include <sys/spa.h>
39 #include <sys/zio.h>
40 #include <sys/dmu_zfetch.h>
41 #include <sys/range_tree.h>
42
43 static kmem_cache_t *dnode_cache;
44 /*
45 * Define DNODE_STATS to turn on statistic gathering. By default, it is only
46 * turned on when DEBUG is also defined.
47 */
48 #ifdef DEBUG
49 #define DNODE_STATS
50 #endif /* DEBUG */
51
52 #ifdef DNODE_STATS
53 #define DNODE_STAT_ADD(stat) ((stat)++)
54 #else
55 #define DNODE_STAT_ADD(stat) /* nothing */
56 #endif /* DNODE_STATS */
57
58 static dnode_phys_t dnode_phys_zero;
59
60 int zfs_default_bs = SPA_MINBLOCKSHIFT;
61 int zfs_default_ibs = DN_MAX_INDBLKSHIFT;
62
63 SYSCTL_DECL(_vfs_zfs);
64 SYSCTL_INT(_vfs_zfs, OID_AUTO, default_bs, CTLFLAG_RWTUN,
65 &zfs_default_bs, 0, "Default dnode block shift");
66 SYSCTL_INT(_vfs_zfs, OID_AUTO, default_ibs, CTLFLAG_RWTUN,
67 &zfs_default_ibs, 0, "Default dnode indirect block shift");
68
69 #ifdef illumos
70 #ifdef _KERNEL
71 static kmem_cbrc_t dnode_move(void *, void *, size_t, void *);
72 #endif /* _KERNEL */
73 #endif
74
75 static int
dbuf_compare(const void * x1,const void * x2)76 dbuf_compare(const void *x1, const void *x2)
77 {
78 const dmu_buf_impl_t *d1 = x1;
79 const dmu_buf_impl_t *d2 = x2;
80
81 int cmp = AVL_CMP(d1->db_level, d2->db_level);
82 if (likely(cmp))
83 return (cmp);
84
85 cmp = AVL_CMP(d1->db_blkid, d2->db_blkid);
86 if (likely(cmp))
87 return (cmp);
88
89 if (d1->db_state == DB_SEARCH) {
90 ASSERT3S(d2->db_state, !=, DB_SEARCH);
91 return (-1);
92 } else if (d2->db_state == DB_SEARCH) {
93 ASSERT3S(d1->db_state, !=, DB_SEARCH);
94 return (1);
95 }
96
97 return (AVL_PCMP(d1, d2));
98 }
99
100 /* ARGSUSED */
101 static int
dnode_cons(void * arg,void * unused,int kmflag)102 dnode_cons(void *arg, void *unused, int kmflag)
103 {
104 dnode_t *dn = arg;
105 int i;
106
107 rw_init(&dn->dn_struct_rwlock, NULL, RW_DEFAULT, NULL);
108 mutex_init(&dn->dn_mtx, NULL, MUTEX_DEFAULT, NULL);
109 mutex_init(&dn->dn_dbufs_mtx, NULL, MUTEX_DEFAULT, NULL);
110 cv_init(&dn->dn_notxholds, NULL, CV_DEFAULT, NULL);
111
112 /*
113 * Every dbuf has a reference, and dropping a tracked reference is
114 * O(number of references), so don't track dn_holds.
115 */
116 refcount_create_untracked(&dn->dn_holds);
117 refcount_create(&dn->dn_tx_holds);
118 list_link_init(&dn->dn_link);
119
120 bzero(&dn->dn_next_nblkptr[0], sizeof (dn->dn_next_nblkptr));
121 bzero(&dn->dn_next_nlevels[0], sizeof (dn->dn_next_nlevels));
122 bzero(&dn->dn_next_indblkshift[0], sizeof (dn->dn_next_indblkshift));
123 bzero(&dn->dn_next_bonustype[0], sizeof (dn->dn_next_bonustype));
124 bzero(&dn->dn_rm_spillblk[0], sizeof (dn->dn_rm_spillblk));
125 bzero(&dn->dn_next_bonuslen[0], sizeof (dn->dn_next_bonuslen));
126 bzero(&dn->dn_next_blksz[0], sizeof (dn->dn_next_blksz));
127
128 for (i = 0; i < TXG_SIZE; i++) {
129 list_link_init(&dn->dn_dirty_link[i]);
130 dn->dn_free_ranges[i] = NULL;
131 list_create(&dn->dn_dirty_records[i],
132 sizeof (dbuf_dirty_record_t),
133 offsetof(dbuf_dirty_record_t, dr_dirty_node));
134 }
135
136 dn->dn_allocated_txg = 0;
137 dn->dn_free_txg = 0;
138 dn->dn_assigned_txg = 0;
139 dn->dn_dirtyctx = 0;
140 dn->dn_dirtyctx_firstset = NULL;
141 dn->dn_bonus = NULL;
142 dn->dn_have_spill = B_FALSE;
143 dn->dn_zio = NULL;
144 dn->dn_oldused = 0;
145 dn->dn_oldflags = 0;
146 dn->dn_olduid = 0;
147 dn->dn_oldgid = 0;
148 dn->dn_newuid = 0;
149 dn->dn_newgid = 0;
150 dn->dn_id_flags = 0;
151
152 dn->dn_dbufs_count = 0;
153 avl_create(&dn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t),
154 offsetof(dmu_buf_impl_t, db_link));
155
156 dn->dn_moved = 0;
157 POINTER_INVALIDATE(&dn->dn_objset);
158 return (0);
159 }
160
161 /* ARGSUSED */
162 static void
dnode_dest(void * arg,void * unused)163 dnode_dest(void *arg, void *unused)
164 {
165 int i;
166 dnode_t *dn = arg;
167
168 rw_destroy(&dn->dn_struct_rwlock);
169 mutex_destroy(&dn->dn_mtx);
170 mutex_destroy(&dn->dn_dbufs_mtx);
171 cv_destroy(&dn->dn_notxholds);
172 refcount_destroy(&dn->dn_holds);
173 refcount_destroy(&dn->dn_tx_holds);
174 ASSERT(!list_link_active(&dn->dn_link));
175
176 for (i = 0; i < TXG_SIZE; i++) {
177 ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
178 ASSERT3P(dn->dn_free_ranges[i], ==, NULL);
179 list_destroy(&dn->dn_dirty_records[i]);
180 ASSERT0(dn->dn_next_nblkptr[i]);
181 ASSERT0(dn->dn_next_nlevels[i]);
182 ASSERT0(dn->dn_next_indblkshift[i]);
183 ASSERT0(dn->dn_next_bonustype[i]);
184 ASSERT0(dn->dn_rm_spillblk[i]);
185 ASSERT0(dn->dn_next_bonuslen[i]);
186 ASSERT0(dn->dn_next_blksz[i]);
187 }
188
189 ASSERT0(dn->dn_allocated_txg);
190 ASSERT0(dn->dn_free_txg);
191 ASSERT0(dn->dn_assigned_txg);
192 ASSERT0(dn->dn_dirtyctx);
193 ASSERT3P(dn->dn_dirtyctx_firstset, ==, NULL);
194 ASSERT3P(dn->dn_bonus, ==, NULL);
195 ASSERT(!dn->dn_have_spill);
196 ASSERT3P(dn->dn_zio, ==, NULL);
197 ASSERT0(dn->dn_oldused);
198 ASSERT0(dn->dn_oldflags);
199 ASSERT0(dn->dn_olduid);
200 ASSERT0(dn->dn_oldgid);
201 ASSERT0(dn->dn_newuid);
202 ASSERT0(dn->dn_newgid);
203 ASSERT0(dn->dn_id_flags);
204
205 ASSERT0(dn->dn_dbufs_count);
206 avl_destroy(&dn->dn_dbufs);
207 }
208
209 void
dnode_init(void)210 dnode_init(void)
211 {
212 ASSERT(dnode_cache == NULL);
213 dnode_cache = kmem_cache_create("dnode_t",
214 sizeof (dnode_t),
215 0, dnode_cons, dnode_dest, NULL, NULL, NULL, 0);
216 #ifdef _KERNEL
217 kmem_cache_set_move(dnode_cache, dnode_move);
218 #endif /* _KERNEL */
219 }
220
221 void
dnode_fini(void)222 dnode_fini(void)
223 {
224 kmem_cache_destroy(dnode_cache);
225 dnode_cache = NULL;
226 }
227
228
229 #ifdef ZFS_DEBUG
230 void
dnode_verify(dnode_t * dn)231 dnode_verify(dnode_t *dn)
232 {
233 int drop_struct_lock = FALSE;
234
235 ASSERT(dn->dn_phys);
236 ASSERT(dn->dn_objset);
237 ASSERT(dn->dn_handle->dnh_dnode == dn);
238
239 ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type));
240
241 if (!(zfs_flags & ZFS_DEBUG_DNODE_VERIFY))
242 return;
243
244 if (!RW_WRITE_HELD(&dn->dn_struct_rwlock)) {
245 rw_enter(&dn->dn_struct_rwlock, RW_READER);
246 drop_struct_lock = TRUE;
247 }
248 if (dn->dn_phys->dn_type != DMU_OT_NONE || dn->dn_allocated_txg != 0) {
249 int i;
250 int max_bonuslen = DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots);
251 ASSERT3U(dn->dn_indblkshift, >=, 0);
252 ASSERT3U(dn->dn_indblkshift, <=, SPA_MAXBLOCKSHIFT);
253 if (dn->dn_datablkshift) {
254 ASSERT3U(dn->dn_datablkshift, >=, SPA_MINBLOCKSHIFT);
255 ASSERT3U(dn->dn_datablkshift, <=, SPA_MAXBLOCKSHIFT);
256 ASSERT3U(1<<dn->dn_datablkshift, ==, dn->dn_datablksz);
257 }
258 ASSERT3U(dn->dn_nlevels, <=, 30);
259 ASSERT(DMU_OT_IS_VALID(dn->dn_type));
260 ASSERT3U(dn->dn_nblkptr, >=, 1);
261 ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR);
262 ASSERT3U(dn->dn_bonuslen, <=, max_bonuslen);
263 ASSERT3U(dn->dn_datablksz, ==,
264 dn->dn_datablkszsec << SPA_MINBLOCKSHIFT);
265 ASSERT3U(ISP2(dn->dn_datablksz), ==, dn->dn_datablkshift != 0);
266 ASSERT3U((dn->dn_nblkptr - 1) * sizeof (blkptr_t) +
267 dn->dn_bonuslen, <=, max_bonuslen);
268 for (i = 0; i < TXG_SIZE; i++) {
269 ASSERT3U(dn->dn_next_nlevels[i], <=, dn->dn_nlevels);
270 }
271 }
272 if (dn->dn_phys->dn_type != DMU_OT_NONE)
273 ASSERT3U(dn->dn_phys->dn_nlevels, <=, dn->dn_nlevels);
274 ASSERT(DMU_OBJECT_IS_SPECIAL(dn->dn_object) || dn->dn_dbuf != NULL);
275 if (dn->dn_dbuf != NULL) {
276 ASSERT3P(dn->dn_phys, ==,
277 (dnode_phys_t *)dn->dn_dbuf->db.db_data +
278 (dn->dn_object % (dn->dn_dbuf->db.db_size >> DNODE_SHIFT)));
279 }
280 if (drop_struct_lock)
281 rw_exit(&dn->dn_struct_rwlock);
282 }
283 #endif
284
285 void
dnode_byteswap(dnode_phys_t * dnp)286 dnode_byteswap(dnode_phys_t *dnp)
287 {
288 uint64_t *buf64 = (void*)&dnp->dn_blkptr;
289 int i;
290
291 if (dnp->dn_type == DMU_OT_NONE) {
292 bzero(dnp, sizeof (dnode_phys_t));
293 return;
294 }
295
296 dnp->dn_datablkszsec = BSWAP_16(dnp->dn_datablkszsec);
297 dnp->dn_bonuslen = BSWAP_16(dnp->dn_bonuslen);
298 dnp->dn_extra_slots = BSWAP_8(dnp->dn_extra_slots);
299 dnp->dn_maxblkid = BSWAP_64(dnp->dn_maxblkid);
300 dnp->dn_used = BSWAP_64(dnp->dn_used);
301
302 /*
303 * dn_nblkptr is only one byte, so it's OK to read it in either
304 * byte order. We can't read dn_bouslen.
305 */
306 ASSERT(dnp->dn_indblkshift <= SPA_MAXBLOCKSHIFT);
307 ASSERT(dnp->dn_nblkptr <= DN_MAX_NBLKPTR);
308 for (i = 0; i < dnp->dn_nblkptr * sizeof (blkptr_t)/8; i++)
309 buf64[i] = BSWAP_64(buf64[i]);
310
311 /*
312 * OK to check dn_bonuslen for zero, because it won't matter if
313 * we have the wrong byte order. This is necessary because the
314 * dnode dnode is smaller than a regular dnode.
315 */
316 if (dnp->dn_bonuslen != 0) {
317 /*
318 * Note that the bonus length calculated here may be
319 * longer than the actual bonus buffer. This is because
320 * we always put the bonus buffer after the last block
321 * pointer (instead of packing it against the end of the
322 * dnode buffer).
323 */
324 int off = (dnp->dn_nblkptr-1) * sizeof (blkptr_t);
325 int slots = dnp->dn_extra_slots + 1;
326 size_t len = DN_SLOTS_TO_BONUSLEN(slots) - off;
327 ASSERT(DMU_OT_IS_VALID(dnp->dn_bonustype));
328 dmu_object_byteswap_t byteswap =
329 DMU_OT_BYTESWAP(dnp->dn_bonustype);
330 dmu_ot_byteswap[byteswap].ob_func(dnp->dn_bonus + off, len);
331 }
332
333 /* Swap SPILL block if we have one */
334 if (dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR)
335 byteswap_uint64_array(DN_SPILL_BLKPTR(dnp), sizeof (blkptr_t));
336 }
337
338 void
dnode_buf_byteswap(void * vbuf,size_t size)339 dnode_buf_byteswap(void *vbuf, size_t size)
340 {
341 int i = 0;
342
343 ASSERT3U(sizeof (dnode_phys_t), ==, (1<<DNODE_SHIFT));
344 ASSERT((size & (sizeof (dnode_phys_t)-1)) == 0);
345
346 while (i < size) {
347 dnode_phys_t *dnp = vbuf + i;
348 dnode_byteswap(dnp);
349
350 i += DNODE_MIN_SIZE;
351 if (dnp->dn_type != DMU_OT_NONE)
352 i += dnp->dn_extra_slots * DNODE_MIN_SIZE;
353 }
354 }
355
356 void
dnode_setbonuslen(dnode_t * dn,int newsize,dmu_tx_t * tx)357 dnode_setbonuslen(dnode_t *dn, int newsize, dmu_tx_t *tx)
358 {
359 ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
360
361 dnode_setdirty(dn, tx);
362 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
363 ASSERT3U(newsize, <=, DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) -
364 (dn->dn_nblkptr-1) * sizeof (blkptr_t));
365 dn->dn_bonuslen = newsize;
366 if (newsize == 0)
367 dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = DN_ZERO_BONUSLEN;
368 else
369 dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen;
370 rw_exit(&dn->dn_struct_rwlock);
371 }
372
373 void
dnode_setbonus_type(dnode_t * dn,dmu_object_type_t newtype,dmu_tx_t * tx)374 dnode_setbonus_type(dnode_t *dn, dmu_object_type_t newtype, dmu_tx_t *tx)
375 {
376 ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
377 dnode_setdirty(dn, tx);
378 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
379 dn->dn_bonustype = newtype;
380 dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype;
381 rw_exit(&dn->dn_struct_rwlock);
382 }
383
384 void
dnode_rm_spill(dnode_t * dn,dmu_tx_t * tx)385 dnode_rm_spill(dnode_t *dn, dmu_tx_t *tx)
386 {
387 ASSERT3U(refcount_count(&dn->dn_holds), >=, 1);
388 ASSERT(RW_WRITE_HELD(&dn->dn_struct_rwlock));
389 dnode_setdirty(dn, tx);
390 dn->dn_rm_spillblk[tx->tx_txg&TXG_MASK] = DN_KILL_SPILLBLK;
391 dn->dn_have_spill = B_FALSE;
392 }
393
394 static void
dnode_setdblksz(dnode_t * dn,int size)395 dnode_setdblksz(dnode_t *dn, int size)
396 {
397 ASSERT0(P2PHASE(size, SPA_MINBLOCKSIZE));
398 ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
399 ASSERT3U(size, >=, SPA_MINBLOCKSIZE);
400 ASSERT3U(size >> SPA_MINBLOCKSHIFT, <,
401 1<<(sizeof (dn->dn_phys->dn_datablkszsec) * 8));
402 dn->dn_datablksz = size;
403 dn->dn_datablkszsec = size >> SPA_MINBLOCKSHIFT;
404 dn->dn_datablkshift = ISP2(size) ? highbit64(size - 1) : 0;
405 }
406
407 static dnode_t *
dnode_create(objset_t * os,dnode_phys_t * dnp,dmu_buf_impl_t * db,uint64_t object,dnode_handle_t * dnh)408 dnode_create(objset_t *os, dnode_phys_t *dnp, dmu_buf_impl_t *db,
409 uint64_t object, dnode_handle_t *dnh)
410 {
411 dnode_t *dn;
412
413 dn = kmem_cache_alloc(dnode_cache, KM_SLEEP);
414 #ifdef _KERNEL
415 ASSERT(!POINTER_IS_VALID(dn->dn_objset));
416 #endif /* _KERNEL */
417 dn->dn_moved = 0;
418
419 /*
420 * Defer setting dn_objset until the dnode is ready to be a candidate
421 * for the dnode_move() callback.
422 */
423 dn->dn_object = object;
424 dn->dn_dbuf = db;
425 dn->dn_handle = dnh;
426 dn->dn_phys = dnp;
427
428 if (dnp->dn_datablkszsec) {
429 dnode_setdblksz(dn, dnp->dn_datablkszsec << SPA_MINBLOCKSHIFT);
430 } else {
431 dn->dn_datablksz = 0;
432 dn->dn_datablkszsec = 0;
433 dn->dn_datablkshift = 0;
434 }
435 dn->dn_indblkshift = dnp->dn_indblkshift;
436 dn->dn_nlevels = dnp->dn_nlevels;
437 dn->dn_type = dnp->dn_type;
438 dn->dn_nblkptr = dnp->dn_nblkptr;
439 dn->dn_checksum = dnp->dn_checksum;
440 dn->dn_compress = dnp->dn_compress;
441 dn->dn_bonustype = dnp->dn_bonustype;
442 dn->dn_bonuslen = dnp->dn_bonuslen;
443 dn->dn_num_slots = dnp->dn_extra_slots + 1;
444 dn->dn_maxblkid = dnp->dn_maxblkid;
445 dn->dn_have_spill = ((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) != 0);
446 dn->dn_id_flags = 0;
447
448 dmu_zfetch_init(&dn->dn_zfetch, dn);
449
450 ASSERT(DMU_OT_IS_VALID(dn->dn_phys->dn_type));
451
452 mutex_enter(&os->os_lock);
453 if (dnh->dnh_dnode != NULL) {
454 /* Lost the allocation race. */
455 mutex_exit(&os->os_lock);
456 kmem_cache_free(dnode_cache, dn);
457 return (dnh->dnh_dnode);
458 }
459
460 /*
461 * Exclude special dnodes from os_dnodes so an empty os_dnodes
462 * signifies that the special dnodes have no references from
463 * their children (the entries in os_dnodes). This allows
464 * dnode_destroy() to easily determine if the last child has
465 * been removed and then complete eviction of the objset.
466 */
467 if (!DMU_OBJECT_IS_SPECIAL(object))
468 list_insert_head(&os->os_dnodes, dn);
469 membar_producer();
470
471 /*
472 * Everything else must be valid before assigning dn_objset
473 * makes the dnode eligible for dnode_move().
474 */
475 dn->dn_objset = os;
476
477 dnh->dnh_dnode = dn;
478 mutex_exit(&os->os_lock);
479
480 arc_space_consume(sizeof (dnode_t), ARC_SPACE_DNODE);
481 return (dn);
482 }
483
484 /*
485 * Caller must be holding the dnode handle, which is released upon return.
486 */
487 static void
dnode_destroy(dnode_t * dn)488 dnode_destroy(dnode_t *dn)
489 {
490 objset_t *os = dn->dn_objset;
491 boolean_t complete_os_eviction = B_FALSE;
492
493 ASSERT((dn->dn_id_flags & DN_ID_NEW_EXIST) == 0);
494
495 mutex_enter(&os->os_lock);
496 POINTER_INVALIDATE(&dn->dn_objset);
497 if (!DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
498 list_remove(&os->os_dnodes, dn);
499 complete_os_eviction =
500 list_is_empty(&os->os_dnodes) &&
501 list_link_active(&os->os_evicting_node);
502 }
503 mutex_exit(&os->os_lock);
504
505 /* the dnode can no longer move, so we can release the handle */
506 zrl_remove(&dn->dn_handle->dnh_zrlock);
507
508 dn->dn_allocated_txg = 0;
509 dn->dn_free_txg = 0;
510 dn->dn_assigned_txg = 0;
511
512 dn->dn_dirtyctx = 0;
513 if (dn->dn_dirtyctx_firstset != NULL) {
514 kmem_free(dn->dn_dirtyctx_firstset, 1);
515 dn->dn_dirtyctx_firstset = NULL;
516 }
517 if (dn->dn_bonus != NULL) {
518 mutex_enter(&dn->dn_bonus->db_mtx);
519 dbuf_destroy(dn->dn_bonus);
520 dn->dn_bonus = NULL;
521 }
522 dn->dn_zio = NULL;
523
524 dn->dn_have_spill = B_FALSE;
525 dn->dn_oldused = 0;
526 dn->dn_oldflags = 0;
527 dn->dn_olduid = 0;
528 dn->dn_oldgid = 0;
529 dn->dn_newuid = 0;
530 dn->dn_newgid = 0;
531 dn->dn_id_flags = 0;
532
533 dmu_zfetch_fini(&dn->dn_zfetch);
534 kmem_cache_free(dnode_cache, dn);
535 arc_space_return(sizeof (dnode_t), ARC_SPACE_DNODE);
536
537 if (complete_os_eviction)
538 dmu_objset_evict_done(os);
539 }
540
541 void
dnode_allocate(dnode_t * dn,dmu_object_type_t ot,int blocksize,int ibs,dmu_object_type_t bonustype,int bonuslen,int dn_slots,dmu_tx_t * tx)542 dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs,
543 dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx)
544 {
545 int i;
546
547 ASSERT3U(dn_slots, >, 0);
548 ASSERT3U(dn_slots << DNODE_SHIFT, <=,
549 spa_maxdnodesize(dmu_objset_spa(dn->dn_objset)));
550 ASSERT3U(blocksize, <=,
551 spa_maxblocksize(dmu_objset_spa(dn->dn_objset)));
552 if (blocksize == 0)
553 blocksize = 1 << zfs_default_bs;
554 else
555 blocksize = P2ROUNDUP(blocksize, SPA_MINBLOCKSIZE);
556
557 if (ibs == 0)
558 ibs = zfs_default_ibs;
559
560 ibs = MIN(MAX(ibs, DN_MIN_INDBLKSHIFT), DN_MAX_INDBLKSHIFT);
561
562 dprintf("os=%p obj=%llu txg=%llu blocksize=%d ibs=%d dn_slots=%d\n",
563 dn->dn_objset, dn->dn_object, tx->tx_txg, blocksize, ibs, dn_slots);
564
565 ASSERT(dn->dn_type == DMU_OT_NONE);
566 ASSERT(bcmp(dn->dn_phys, &dnode_phys_zero, sizeof (dnode_phys_t)) == 0);
567 ASSERT(dn->dn_phys->dn_type == DMU_OT_NONE);
568 ASSERT(ot != DMU_OT_NONE);
569 ASSERT(DMU_OT_IS_VALID(ot));
570 ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) ||
571 (bonustype == DMU_OT_SA && bonuslen == 0) ||
572 (bonustype != DMU_OT_NONE && bonuslen != 0));
573 ASSERT(DMU_OT_IS_VALID(bonustype));
574 ASSERT3U(bonuslen, <=, DN_SLOTS_TO_BONUSLEN(dn_slots));
575 ASSERT(dn->dn_type == DMU_OT_NONE);
576 ASSERT0(dn->dn_maxblkid);
577 ASSERT0(dn->dn_allocated_txg);
578 ASSERT0(dn->dn_assigned_txg);
579 ASSERT(refcount_is_zero(&dn->dn_tx_holds));
580 ASSERT3U(refcount_count(&dn->dn_holds), <=, 1);
581 ASSERT(avl_is_empty(&dn->dn_dbufs));
582
583 for (i = 0; i < TXG_SIZE; i++) {
584 ASSERT0(dn->dn_next_nblkptr[i]);
585 ASSERT0(dn->dn_next_nlevels[i]);
586 ASSERT0(dn->dn_next_indblkshift[i]);
587 ASSERT0(dn->dn_next_bonuslen[i]);
588 ASSERT0(dn->dn_next_bonustype[i]);
589 ASSERT0(dn->dn_rm_spillblk[i]);
590 ASSERT0(dn->dn_next_blksz[i]);
591 ASSERT(!list_link_active(&dn->dn_dirty_link[i]));
592 ASSERT3P(list_head(&dn->dn_dirty_records[i]), ==, NULL);
593 ASSERT3P(dn->dn_free_ranges[i], ==, NULL);
594 }
595
596 dn->dn_type = ot;
597 dnode_setdblksz(dn, blocksize);
598 dn->dn_indblkshift = ibs;
599 dn->dn_nlevels = 1;
600 dn->dn_num_slots = dn_slots;
601 if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */
602 dn->dn_nblkptr = 1;
603 else {
604 dn->dn_nblkptr = MIN(DN_MAX_NBLKPTR,
605 1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >>
606 SPA_BLKPTRSHIFT));
607 }
608
609 dn->dn_bonustype = bonustype;
610 dn->dn_bonuslen = bonuslen;
611 dn->dn_checksum = ZIO_CHECKSUM_INHERIT;
612 dn->dn_compress = ZIO_COMPRESS_INHERIT;
613 dn->dn_dirtyctx = 0;
614
615 dn->dn_free_txg = 0;
616 if (dn->dn_dirtyctx_firstset) {
617 kmem_free(dn->dn_dirtyctx_firstset, 1);
618 dn->dn_dirtyctx_firstset = NULL;
619 }
620
621 dn->dn_allocated_txg = tx->tx_txg;
622 dn->dn_id_flags = 0;
623
624 dnode_setdirty(dn, tx);
625 dn->dn_next_indblkshift[tx->tx_txg & TXG_MASK] = ibs;
626 dn->dn_next_bonuslen[tx->tx_txg & TXG_MASK] = dn->dn_bonuslen;
627 dn->dn_next_bonustype[tx->tx_txg & TXG_MASK] = dn->dn_bonustype;
628 dn->dn_next_blksz[tx->tx_txg & TXG_MASK] = dn->dn_datablksz;
629 }
630
631 void
dnode_reallocate(dnode_t * dn,dmu_object_type_t ot,int blocksize,dmu_object_type_t bonustype,int bonuslen,int dn_slots,dmu_tx_t * tx)632 dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
633 dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx)
634 {
635 int nblkptr;
636
637 ASSERT3U(blocksize, >=, SPA_MINBLOCKSIZE);
638 ASSERT3U(blocksize, <=,
639 spa_maxblocksize(dmu_objset_spa(dn->dn_objset)));
640 ASSERT0(blocksize % SPA_MINBLOCKSIZE);
641 ASSERT(dn->dn_object != DMU_META_DNODE_OBJECT || dmu_tx_private_ok(tx));
642 ASSERT(tx->tx_txg != 0);
643 ASSERT((bonustype == DMU_OT_NONE && bonuslen == 0) ||
644 (bonustype != DMU_OT_NONE && bonuslen != 0) ||
645 (bonustype == DMU_OT_SA && bonuslen == 0));
646 ASSERT(DMU_OT_IS_VALID(bonustype));
647 ASSERT3U(bonuslen, <=,
648 DN_BONUS_SIZE(spa_maxdnodesize(dmu_objset_spa(dn->dn_objset))));
649
650 dn_slots = dn_slots > 0 ? dn_slots : DNODE_MIN_SLOTS;
651
652 /* clean up any unreferenced dbufs */
653 dnode_evict_dbufs(dn);
654
655 dn->dn_id_flags = 0;
656
657 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
658 dnode_setdirty(dn, tx);
659 if (dn->dn_datablksz != blocksize) {
660 /* change blocksize */
661 ASSERT(dn->dn_maxblkid == 0 &&
662 (BP_IS_HOLE(&dn->dn_phys->dn_blkptr[0]) ||
663 dnode_block_freed(dn, 0)));
664 dnode_setdblksz(dn, blocksize);
665 dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = blocksize;
666 }
667 if (dn->dn_bonuslen != bonuslen)
668 dn->dn_next_bonuslen[tx->tx_txg&TXG_MASK] = bonuslen;
669
670 if (bonustype == DMU_OT_SA) /* Maximize bonus space for SA */
671 nblkptr = 1;
672 else
673 nblkptr = MIN(DN_MAX_NBLKPTR,
674 1 + ((DN_SLOTS_TO_BONUSLEN(dn_slots) - bonuslen) >>
675 SPA_BLKPTRSHIFT));
676 if (dn->dn_bonustype != bonustype)
677 dn->dn_next_bonustype[tx->tx_txg&TXG_MASK] = bonustype;
678 if (dn->dn_nblkptr != nblkptr)
679 dn->dn_next_nblkptr[tx->tx_txg&TXG_MASK] = nblkptr;
680 if (dn->dn_phys->dn_flags & DNODE_FLAG_SPILL_BLKPTR) {
681 dbuf_rm_spill(dn, tx);
682 dnode_rm_spill(dn, tx);
683 }
684 rw_exit(&dn->dn_struct_rwlock);
685
686 /* change type */
687 dn->dn_type = ot;
688
689 /* change bonus size and type */
690 mutex_enter(&dn->dn_mtx);
691 dn->dn_bonustype = bonustype;
692 dn->dn_bonuslen = bonuslen;
693 dn->dn_num_slots = dn_slots;
694 dn->dn_nblkptr = nblkptr;
695 dn->dn_checksum = ZIO_CHECKSUM_INHERIT;
696 dn->dn_compress = ZIO_COMPRESS_INHERIT;
697 ASSERT3U(dn->dn_nblkptr, <=, DN_MAX_NBLKPTR);
698
699 /* fix up the bonus db_size */
700 if (dn->dn_bonus) {
701 dn->dn_bonus->db.db_size =
702 DN_SLOTS_TO_BONUSLEN(dn->dn_num_slots) -
703 (dn->dn_nblkptr-1) * sizeof (blkptr_t);
704 ASSERT(dn->dn_bonuslen <= dn->dn_bonus->db.db_size);
705 }
706
707 dn->dn_allocated_txg = tx->tx_txg;
708 mutex_exit(&dn->dn_mtx);
709 }
710
711 #ifdef DNODE_STATS
712 static struct {
713 uint64_t dms_dnode_invalid;
714 uint64_t dms_dnode_recheck1;
715 uint64_t dms_dnode_recheck2;
716 uint64_t dms_dnode_special;
717 uint64_t dms_dnode_handle;
718 uint64_t dms_dnode_rwlock;
719 uint64_t dms_dnode_active;
720 } dnode_move_stats;
721 #endif /* DNODE_STATS */
722
723 #ifdef _KERNEL
724 static void
dnode_move_impl(dnode_t * odn,dnode_t * ndn)725 dnode_move_impl(dnode_t *odn, dnode_t *ndn)
726 {
727 int i;
728
729 ASSERT(!RW_LOCK_HELD(&odn->dn_struct_rwlock));
730 ASSERT(MUTEX_NOT_HELD(&odn->dn_mtx));
731 ASSERT(MUTEX_NOT_HELD(&odn->dn_dbufs_mtx));
732 ASSERT(!RW_LOCK_HELD(&odn->dn_zfetch.zf_rwlock));
733
734 /* Copy fields. */
735 ndn->dn_objset = odn->dn_objset;
736 ndn->dn_object = odn->dn_object;
737 ndn->dn_dbuf = odn->dn_dbuf;
738 ndn->dn_handle = odn->dn_handle;
739 ndn->dn_phys = odn->dn_phys;
740 ndn->dn_type = odn->dn_type;
741 ndn->dn_bonuslen = odn->dn_bonuslen;
742 ndn->dn_bonustype = odn->dn_bonustype;
743 ndn->dn_nblkptr = odn->dn_nblkptr;
744 ndn->dn_checksum = odn->dn_checksum;
745 ndn->dn_compress = odn->dn_compress;
746 ndn->dn_nlevels = odn->dn_nlevels;
747 ndn->dn_indblkshift = odn->dn_indblkshift;
748 ndn->dn_datablkshift = odn->dn_datablkshift;
749 ndn->dn_datablkszsec = odn->dn_datablkszsec;
750 ndn->dn_datablksz = odn->dn_datablksz;
751 ndn->dn_maxblkid = odn->dn_maxblkid;
752 bcopy(&odn->dn_next_type[0], &ndn->dn_next_type[0],
753 sizeof (odn->dn_next_type));
754 bcopy(&odn->dn_next_nblkptr[0], &ndn->dn_next_nblkptr[0],
755 sizeof (odn->dn_next_nblkptr));
756 bcopy(&odn->dn_next_nlevels[0], &ndn->dn_next_nlevels[0],
757 sizeof (odn->dn_next_nlevels));
758 bcopy(&odn->dn_next_indblkshift[0], &ndn->dn_next_indblkshift[0],
759 sizeof (odn->dn_next_indblkshift));
760 bcopy(&odn->dn_next_bonustype[0], &ndn->dn_next_bonustype[0],
761 sizeof (odn->dn_next_bonustype));
762 bcopy(&odn->dn_rm_spillblk[0], &ndn->dn_rm_spillblk[0],
763 sizeof (odn->dn_rm_spillblk));
764 bcopy(&odn->dn_next_bonuslen[0], &ndn->dn_next_bonuslen[0],
765 sizeof (odn->dn_next_bonuslen));
766 bcopy(&odn->dn_next_blksz[0], &ndn->dn_next_blksz[0],
767 sizeof (odn->dn_next_blksz));
768 for (i = 0; i < TXG_SIZE; i++) {
769 list_move_tail(&ndn->dn_dirty_records[i],
770 &odn->dn_dirty_records[i]);
771 }
772 bcopy(&odn->dn_free_ranges[0], &ndn->dn_free_ranges[0],
773 sizeof (odn->dn_free_ranges));
774 ndn->dn_allocated_txg = odn->dn_allocated_txg;
775 ndn->dn_free_txg = odn->dn_free_txg;
776 ndn->dn_assigned_txg = odn->dn_assigned_txg;
777 ndn->dn_dirtyctx = odn->dn_dirtyctx;
778 ndn->dn_dirtyctx_firstset = odn->dn_dirtyctx_firstset;
779 ASSERT(refcount_count(&odn->dn_tx_holds) == 0);
780 refcount_transfer(&ndn->dn_holds, &odn->dn_holds);
781 ASSERT(avl_is_empty(&ndn->dn_dbufs));
782 avl_swap(&ndn->dn_dbufs, &odn->dn_dbufs);
783 ndn->dn_dbufs_count = odn->dn_dbufs_count;
784 ndn->dn_bonus = odn->dn_bonus;
785 ndn->dn_have_spill = odn->dn_have_spill;
786 ndn->dn_zio = odn->dn_zio;
787 ndn->dn_oldused = odn->dn_oldused;
788 ndn->dn_oldflags = odn->dn_oldflags;
789 ndn->dn_olduid = odn->dn_olduid;
790 ndn->dn_oldgid = odn->dn_oldgid;
791 ndn->dn_newuid = odn->dn_newuid;
792 ndn->dn_newgid = odn->dn_newgid;
793 ndn->dn_id_flags = odn->dn_id_flags;
794 dmu_zfetch_init(&ndn->dn_zfetch, NULL);
795 list_move_tail(&ndn->dn_zfetch.zf_stream, &odn->dn_zfetch.zf_stream);
796 ndn->dn_zfetch.zf_dnode = odn->dn_zfetch.zf_dnode;
797
798 /*
799 * Update back pointers. Updating the handle fixes the back pointer of
800 * every descendant dbuf as well as the bonus dbuf.
801 */
802 ASSERT(ndn->dn_handle->dnh_dnode == odn);
803 ndn->dn_handle->dnh_dnode = ndn;
804 if (ndn->dn_zfetch.zf_dnode == odn) {
805 ndn->dn_zfetch.zf_dnode = ndn;
806 }
807
808 /*
809 * Invalidate the original dnode by clearing all of its back pointers.
810 */
811 odn->dn_dbuf = NULL;
812 odn->dn_handle = NULL;
813 avl_create(&odn->dn_dbufs, dbuf_compare, sizeof (dmu_buf_impl_t),
814 offsetof(dmu_buf_impl_t, db_link));
815 odn->dn_dbufs_count = 0;
816 odn->dn_bonus = NULL;
817 odn->dn_zfetch.zf_dnode = NULL;
818
819 /*
820 * Set the low bit of the objset pointer to ensure that dnode_move()
821 * recognizes the dnode as invalid in any subsequent callback.
822 */
823 POINTER_INVALIDATE(&odn->dn_objset);
824
825 /*
826 * Satisfy the destructor.
827 */
828 for (i = 0; i < TXG_SIZE; i++) {
829 list_create(&odn->dn_dirty_records[i],
830 sizeof (dbuf_dirty_record_t),
831 offsetof(dbuf_dirty_record_t, dr_dirty_node));
832 odn->dn_free_ranges[i] = NULL;
833 odn->dn_next_nlevels[i] = 0;
834 odn->dn_next_indblkshift[i] = 0;
835 odn->dn_next_bonustype[i] = 0;
836 odn->dn_rm_spillblk[i] = 0;
837 odn->dn_next_bonuslen[i] = 0;
838 odn->dn_next_blksz[i] = 0;
839 }
840 odn->dn_allocated_txg = 0;
841 odn->dn_free_txg = 0;
842 odn->dn_assigned_txg = 0;
843 odn->dn_dirtyctx = 0;
844 odn->dn_dirtyctx_firstset = NULL;
845 odn->dn_have_spill = B_FALSE;
846 odn->dn_zio = NULL;
847 odn->dn_oldused = 0;
848 odn->dn_oldflags = 0;
849 odn->dn_olduid = 0;
850 odn->dn_oldgid = 0;
851 odn->dn_newuid = 0;
852 odn->dn_newgid = 0;
853 odn->dn_id_flags = 0;
854
855 /*
856 * Mark the dnode.
857 */
858 ndn->dn_moved = 1;
859 odn->dn_moved = (uint8_t)-1;
860 }
861
862 #ifdef illumos
863 /*ARGSUSED*/
864 static kmem_cbrc_t
dnode_move(void * buf,void * newbuf,size_t size,void * arg)865 dnode_move(void *buf, void *newbuf, size_t size, void *arg)
866 {
867 dnode_t *odn = buf, *ndn = newbuf;
868 objset_t *os;
869 int64_t refcount;
870 uint32_t dbufs;
871
872 /*
873 * The dnode is on the objset's list of known dnodes if the objset
874 * pointer is valid. We set the low bit of the objset pointer when
875 * freeing the dnode to invalidate it, and the memory patterns written
876 * by kmem (baddcafe and deadbeef) set at least one of the two low bits.
877 * A newly created dnode sets the objset pointer last of all to indicate
878 * that the dnode is known and in a valid state to be moved by this
879 * function.
880 */
881 os = odn->dn_objset;
882 if (!POINTER_IS_VALID(os)) {
883 DNODE_STAT_ADD(dnode_move_stats.dms_dnode_invalid);
884 return (KMEM_CBRC_DONT_KNOW);
885 }
886
887 /*
888 * Ensure that the objset does not go away during the move.
889 */
890 rw_enter(&os_lock, RW_WRITER);
891 if (os != odn->dn_objset) {
892 rw_exit(&os_lock);
893 DNODE_STAT_ADD(dnode_move_stats.dms_dnode_recheck1);
894 return (KMEM_CBRC_DONT_KNOW);
895 }
896
897 /*
898 * If the dnode is still valid, then so is the objset. We know that no
899 * valid objset can be freed while we hold os_lock, so we can safely
900 * ensure that the objset remains in use.
901 */
902 mutex_enter(&os->os_lock);
903
904 /*
905 * Recheck the objset pointer in case the dnode was removed just before
906 * acquiring the lock.
907 */
908 if (os != odn->dn_objset) {
909 mutex_exit(&os->os_lock);
910 rw_exit(&os_lock);
911 DNODE_STAT_ADD(dnode_move_stats.dms_dnode_recheck2);
912 return (KMEM_CBRC_DONT_KNOW);
913 }
914
915 /*
916 * At this point we know that as long as we hold os->os_lock, the dnode
917 * cannot be freed and fields within the dnode can be safely accessed.
918 * The objset listing this dnode cannot go away as long as this dnode is
919 * on its list.
920 */
921 rw_exit(&os_lock);
922 if (DMU_OBJECT_IS_SPECIAL(odn->dn_object)) {
923 mutex_exit(&os->os_lock);
924 DNODE_STAT_ADD(dnode_move_stats.dms_dnode_special);
925 return (KMEM_CBRC_NO);
926 }
927 ASSERT(odn->dn_dbuf != NULL); /* only "special" dnodes have no parent */
928
929 /*
930 * Lock the dnode handle to prevent the dnode from obtaining any new
931 * holds. This also prevents the descendant dbufs and the bonus dbuf
932 * from accessing the dnode, so that we can discount their holds. The
933 * handle is safe to access because we know that while the dnode cannot
934 * go away, neither can its handle. Once we hold dnh_zrlock, we can
935 * safely move any dnode referenced only by dbufs.
936 */
937 if (!zrl_tryenter(&odn->dn_handle->dnh_zrlock)) {
938 mutex_exit(&os->os_lock);
939 DNODE_STAT_ADD(dnode_move_stats.dms_dnode_handle);
940 return (KMEM_CBRC_LATER);
941 }
942
943 /*
944 * Ensure a consistent view of the dnode's holds and the dnode's dbufs.
945 * We need to guarantee that there is a hold for every dbuf in order to
946 * determine whether the dnode is actively referenced. Falsely matching
947 * a dbuf to an active hold would lead to an unsafe move. It's possible
948 * that a thread already having an active dnode hold is about to add a
949 * dbuf, and we can't compare hold and dbuf counts while the add is in
950 * progress.
951 */
952 if (!rw_tryenter(&odn->dn_struct_rwlock, RW_WRITER)) {
953 zrl_exit(&odn->dn_handle->dnh_zrlock);
954 mutex_exit(&os->os_lock);
955 DNODE_STAT_ADD(dnode_move_stats.dms_dnode_rwlock);
956 return (KMEM_CBRC_LATER);
957 }
958
959 /*
960 * A dbuf may be removed (evicted) without an active dnode hold. In that
961 * case, the dbuf count is decremented under the handle lock before the
962 * dbuf's hold is released. This order ensures that if we count the hold
963 * after the dbuf is removed but before its hold is released, we will
964 * treat the unmatched hold as active and exit safely. If we count the
965 * hold before the dbuf is removed, the hold is discounted, and the
966 * removal is blocked until the move completes.
967 */
968 refcount = refcount_count(&odn->dn_holds);
969 ASSERT(refcount >= 0);
970 dbufs = odn->dn_dbufs_count;
971
972 /* We can't have more dbufs than dnode holds. */
973 ASSERT3U(dbufs, <=, refcount);
974 DTRACE_PROBE3(dnode__move, dnode_t *, odn, int64_t, refcount,
975 uint32_t, dbufs);
976
977 if (refcount > dbufs) {
978 rw_exit(&odn->dn_struct_rwlock);
979 zrl_exit(&odn->dn_handle->dnh_zrlock);
980 mutex_exit(&os->os_lock);
981 DNODE_STAT_ADD(dnode_move_stats.dms_dnode_active);
982 return (KMEM_CBRC_LATER);
983 }
984
985 rw_exit(&odn->dn_struct_rwlock);
986
987 /*
988 * At this point we know that anyone with a hold on the dnode is not
989 * actively referencing it. The dnode is known and in a valid state to
990 * move. We're holding the locks needed to execute the critical section.
991 */
992 dnode_move_impl(odn, ndn);
993
994 list_link_replace(&odn->dn_link, &ndn->dn_link);
995 /* If the dnode was safe to move, the refcount cannot have changed. */
996 ASSERT(refcount == refcount_count(&ndn->dn_holds));
997 ASSERT(dbufs == ndn->dn_dbufs_count);
998 zrl_exit(&ndn->dn_handle->dnh_zrlock); /* handle has moved */
999 mutex_exit(&os->os_lock);
1000
1001 return (KMEM_CBRC_YES);
1002 }
1003 #endif /* illumos */
1004 #endif /* _KERNEL */
1005
1006 void
dnode_special_close(dnode_handle_t * dnh)1007 dnode_special_close(dnode_handle_t *dnh)
1008 {
1009 dnode_t *dn = dnh->dnh_dnode;
1010
1011 /*
1012 * Wait for final references to the dnode to clear. This can
1013 * only happen if the arc is asyncronously evicting state that
1014 * has a hold on this dnode while we are trying to evict this
1015 * dnode.
1016 */
1017 while (refcount_count(&dn->dn_holds) > 0)
1018 delay(1);
1019 ASSERT(dn->dn_dbuf == NULL ||
1020 dmu_buf_get_user(&dn->dn_dbuf->db) == NULL);
1021 zrl_add(&dnh->dnh_zrlock);
1022 dnode_destroy(dn); /* implicit zrl_remove() */
1023 zrl_destroy(&dnh->dnh_zrlock);
1024 dnh->dnh_dnode = NULL;
1025 }
1026
1027 void
dnode_special_open(objset_t * os,dnode_phys_t * dnp,uint64_t object,dnode_handle_t * dnh)1028 dnode_special_open(objset_t *os, dnode_phys_t *dnp, uint64_t object,
1029 dnode_handle_t *dnh)
1030 {
1031 dnode_t *dn;
1032
1033 dn = dnode_create(os, dnp, NULL, object, dnh);
1034 zrl_init(&dnh->dnh_zrlock);
1035 DNODE_VERIFY(dn);
1036 }
1037
1038 static void
dnode_buf_evict_async(void * dbu)1039 dnode_buf_evict_async(void *dbu)
1040 {
1041 dnode_children_t *children_dnodes = dbu;
1042 int i;
1043
1044 for (i = 0; i < children_dnodes->dnc_count; i++) {
1045 dnode_handle_t *dnh = &children_dnodes->dnc_children[i];
1046 dnode_t *dn;
1047
1048 /*
1049 * The dnode handle lock guards against the dnode moving to
1050 * another valid address, so there is no need here to guard
1051 * against changes to or from NULL.
1052 */
1053 if (dnh->dnh_dnode == NULL) {
1054 zrl_destroy(&dnh->dnh_zrlock);
1055 continue;
1056 }
1057
1058 zrl_add(&dnh->dnh_zrlock);
1059 dn = dnh->dnh_dnode;
1060 /*
1061 * If there are holds on this dnode, then there should
1062 * be holds on the dnode's containing dbuf as well; thus
1063 * it wouldn't be eligible for eviction and this function
1064 * would not have been called.
1065 */
1066 ASSERT(refcount_is_zero(&dn->dn_holds));
1067 ASSERT(refcount_is_zero(&dn->dn_tx_holds));
1068
1069 dnode_destroy(dn); /* implicit zrl_remove() */
1070 zrl_destroy(&dnh->dnh_zrlock);
1071 dnh->dnh_dnode = NULL;
1072 }
1073 kmem_free(children_dnodes, sizeof (dnode_children_t) +
1074 children_dnodes->dnc_count * sizeof (dnode_handle_t));
1075 }
1076
1077 /*
1078 * Return true if the given index is interior to a dnode already
1079 * allocated in the block. That is, the index is neither free nor
1080 * allocated, but is consumed by a large dnode.
1081 *
1082 * The dnode_phys_t buffer may not be in sync with the in-core dnode
1083 * structure, so we try to check the dnode structure first and fall back
1084 * to the dnode_phys_t buffer it doesn't exist.
1085 */
1086 static boolean_t
dnode_is_consumed(dmu_buf_impl_t * db,int idx)1087 dnode_is_consumed(dmu_buf_impl_t *db, int idx)
1088 {
1089 dnode_handle_t *dnh;
1090 dmu_object_type_t ot;
1091 dnode_children_t *children_dnodes;
1092 dnode_phys_t *dn_block;
1093 int skip;
1094 int i;
1095
1096 children_dnodes = dmu_buf_get_user(&db->db);
1097 dn_block = (dnode_phys_t *)db->db.db_data;
1098
1099 for (i = 0; i < idx; i += skip) {
1100 dnh = &children_dnodes->dnc_children[i];
1101
1102 zrl_add(&dnh->dnh_zrlock);
1103 if (dnh->dnh_dnode != NULL) {
1104 ot = dnh->dnh_dnode->dn_type;
1105 skip = dnh->dnh_dnode->dn_num_slots;
1106 } else {
1107 ot = dn_block[i].dn_type;
1108 skip = dn_block[i].dn_extra_slots + 1;
1109 }
1110 zrl_remove(&dnh->dnh_zrlock);
1111
1112 if (ot == DMU_OT_NONE)
1113 skip = 1;
1114 }
1115
1116 return (i > idx);
1117 }
1118
1119 /*
1120 * Return true if the given index in the dnode block is a valid
1121 * allocated dnode. That is, the index is not consumed by a large
1122 * dnode and is not free.
1123 *
1124 * The dnode_phys_t buffer may not be in sync with the in-core dnode
1125 * structure, so we try to check the dnode structure first and fall back
1126 * to the dnode_phys_t buffer it doesn't exist.
1127 */
1128 static boolean_t
dnode_is_allocated(dmu_buf_impl_t * db,int idx)1129 dnode_is_allocated(dmu_buf_impl_t *db, int idx)
1130 {
1131 dnode_handle_t *dnh;
1132 dmu_object_type_t ot;
1133 dnode_children_t *children_dnodes;
1134 dnode_phys_t *dn_block;
1135
1136 if (dnode_is_consumed(db, idx))
1137 return (B_FALSE);
1138
1139 children_dnodes = dmu_buf_get_user(&db->db);
1140 dn_block = (dnode_phys_t *)db->db.db_data;
1141
1142 dnh = &children_dnodes->dnc_children[idx];
1143
1144 zrl_add(&dnh->dnh_zrlock);
1145 if (dnh->dnh_dnode != NULL)
1146 ot = dnh->dnh_dnode->dn_type;
1147 else
1148 ot = dn_block[idx].dn_type;
1149 zrl_remove(&dnh->dnh_zrlock);
1150
1151 return (ot != DMU_OT_NONE);
1152 }
1153
1154 /*
1155 * Return true if the given range of indices in the dnode block are
1156 * free. That is, the starting index is not consumed by a large dnode
1157 * and none of the indices are allocated.
1158 *
1159 * The dnode_phys_t buffer may not be in sync with the in-core dnode
1160 * structure, so we try to check the dnode structure first and fall back
1161 * to the dnode_phys_t buffer it doesn't exist.
1162 */
1163 static boolean_t
dnode_is_free(dmu_buf_impl_t * db,int idx,int slots)1164 dnode_is_free(dmu_buf_impl_t *db, int idx, int slots)
1165 {
1166 dnode_handle_t *dnh;
1167 dmu_object_type_t ot;
1168 dnode_children_t *children_dnodes;
1169 dnode_phys_t *dn_block;
1170 int i;
1171
1172 if (idx + slots > DNODES_PER_BLOCK)
1173 return (B_FALSE);
1174
1175 children_dnodes = dmu_buf_get_user(&db->db);
1176 dn_block = (dnode_phys_t *)db->db.db_data;
1177
1178 if (dnode_is_consumed(db, idx))
1179 return (B_FALSE);
1180
1181 for (i = idx; i < idx + slots; i++) {
1182 dnh = &children_dnodes->dnc_children[i];
1183
1184 zrl_add(&dnh->dnh_zrlock);
1185 if (dnh->dnh_dnode != NULL)
1186 ot = dnh->dnh_dnode->dn_type;
1187 else
1188 ot = dn_block[i].dn_type;
1189 zrl_remove(&dnh->dnh_zrlock);
1190
1191 if (ot != DMU_OT_NONE)
1192 return (B_FALSE);
1193 }
1194
1195 return (B_TRUE);
1196 }
1197
1198 /*
1199 * errors:
1200 * EINVAL - invalid object number.
1201 * ENOSPC - hole too small to fulfill "slots" request
1202 * EIO - i/o error.
1203 * succeeds even for free dnodes.
1204 */
1205 int
dnode_hold_impl(objset_t * os,uint64_t object,int flag,int slots,void * tag,dnode_t ** dnp)1206 dnode_hold_impl(objset_t *os, uint64_t object, int flag, int slots,
1207 void *tag, dnode_t **dnp)
1208 {
1209 int epb, idx, err, i;
1210 int drop_struct_lock = FALSE;
1211 int type;
1212 uint64_t blk;
1213 dnode_t *mdn, *dn;
1214 dmu_buf_impl_t *db;
1215 dnode_children_t *children_dnodes;
1216 dnode_phys_t *dn_block_begin;
1217 dnode_handle_t *dnh;
1218
1219 ASSERT(!(flag & DNODE_MUST_BE_ALLOCATED) || (slots == 0));
1220 ASSERT(!(flag & DNODE_MUST_BE_FREE) || (slots > 0));
1221
1222 /*
1223 * If you are holding the spa config lock as writer, you shouldn't
1224 * be asking the DMU to do *anything* unless it's the root pool
1225 * which may require us to read from the root filesystem while
1226 * holding some (not all) of the locks as writer.
1227 */
1228 ASSERT(spa_config_held(os->os_spa, SCL_ALL, RW_WRITER) == 0 ||
1229 (spa_is_root(os->os_spa) &&
1230 spa_config_held(os->os_spa, SCL_STATE, RW_WRITER)));
1231
1232 ASSERT((flag & DNODE_MUST_BE_ALLOCATED) || (flag & DNODE_MUST_BE_FREE));
1233
1234 if (object == DMU_USERUSED_OBJECT || object == DMU_GROUPUSED_OBJECT) {
1235 dn = (object == DMU_USERUSED_OBJECT) ?
1236 DMU_USERUSED_DNODE(os) : DMU_GROUPUSED_DNODE(os);
1237 if (dn == NULL)
1238 return (SET_ERROR(ENOENT));
1239 type = dn->dn_type;
1240 if ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE)
1241 return (SET_ERROR(ENOENT));
1242 if ((flag & DNODE_MUST_BE_FREE) && type != DMU_OT_NONE)
1243 return (SET_ERROR(EEXIST));
1244 DNODE_VERIFY(dn);
1245 (void) refcount_add(&dn->dn_holds, tag);
1246 *dnp = dn;
1247 return (0);
1248 }
1249
1250 if (object == 0 || object >= DN_MAX_OBJECT)
1251 return (SET_ERROR(EINVAL));
1252
1253 mdn = DMU_META_DNODE(os);
1254 ASSERT(mdn->dn_object == DMU_META_DNODE_OBJECT);
1255
1256 DNODE_VERIFY(mdn);
1257
1258 if (!RW_WRITE_HELD(&mdn->dn_struct_rwlock)) {
1259 rw_enter(&mdn->dn_struct_rwlock, RW_READER);
1260 drop_struct_lock = TRUE;
1261 }
1262
1263 blk = dbuf_whichblock(mdn, 0, object * sizeof (dnode_phys_t));
1264
1265 db = dbuf_hold(mdn, blk, FTAG);
1266 if (drop_struct_lock)
1267 rw_exit(&mdn->dn_struct_rwlock);
1268 if (db == NULL)
1269 return (SET_ERROR(EIO));
1270 err = dbuf_read(db, NULL, DB_RF_CANFAIL);
1271 if (err) {
1272 dbuf_rele(db, FTAG);
1273 return (err);
1274 }
1275
1276 ASSERT3U(db->db.db_size, >=, 1<<DNODE_SHIFT);
1277 epb = db->db.db_size >> DNODE_SHIFT;
1278
1279 ASSERT(DB_DNODE(db)->dn_type == DMU_OT_DNODE);
1280 children_dnodes = dmu_buf_get_user(&db->db);
1281 if (children_dnodes == NULL) {
1282 dnode_children_t *winner;
1283 children_dnodes = kmem_zalloc(sizeof (dnode_children_t) +
1284 epb * sizeof (dnode_handle_t), KM_SLEEP);
1285 children_dnodes->dnc_count = epb;
1286 dnh = &children_dnodes->dnc_children[0];
1287 for (i = 0; i < epb; i++) {
1288 zrl_init(&dnh[i].dnh_zrlock);
1289 }
1290 dmu_buf_init_user(&children_dnodes->dnc_dbu, NULL,
1291 dnode_buf_evict_async, NULL);
1292 winner = dmu_buf_set_user(&db->db, &children_dnodes->dnc_dbu);
1293 if (winner != NULL) {
1294
1295 for (i = 0; i < epb; i++) {
1296 zrl_destroy(&dnh[i].dnh_zrlock);
1297 }
1298
1299 kmem_free(children_dnodes, sizeof (dnode_children_t) +
1300 epb * sizeof (dnode_handle_t));
1301 children_dnodes = winner;
1302 }
1303 }
1304 ASSERT(children_dnodes->dnc_count == epb);
1305
1306 idx = object & (epb - 1);
1307 dn_block_begin = (dnode_phys_t *)db->db.db_data;
1308
1309 if ((flag & DNODE_MUST_BE_FREE) && !dnode_is_free(db, idx, slots)) {
1310 dbuf_rele(db, FTAG);
1311 return (ENOSPC);
1312 } else if ((flag & DNODE_MUST_BE_ALLOCATED) &&
1313 !dnode_is_allocated(db, idx)) {
1314 dbuf_rele(db, FTAG);
1315 return (ENOENT);
1316 }
1317
1318 dnh = &children_dnodes->dnc_children[idx];
1319 zrl_add(&dnh->dnh_zrlock);
1320 dn = dnh->dnh_dnode;
1321 if (dn == NULL)
1322 dn = dnode_create(os, dn_block_begin + idx, db, object, dnh);
1323
1324 mutex_enter(&dn->dn_mtx);
1325 type = dn->dn_type;
1326 if (dn->dn_free_txg ||
1327 ((flag & DNODE_MUST_BE_ALLOCATED) && type == DMU_OT_NONE) ||
1328 ((flag & DNODE_MUST_BE_FREE) &&
1329 (type != DMU_OT_NONE || !refcount_is_zero(&dn->dn_holds)))) {
1330 mutex_exit(&dn->dn_mtx);
1331 zrl_remove(&dnh->dnh_zrlock);
1332 dbuf_rele(db, FTAG);
1333 return ((flag & DNODE_MUST_BE_ALLOCATED) ? ENOENT : EEXIST);
1334 }
1335 if (refcount_add(&dn->dn_holds, tag) == 1)
1336 dbuf_add_ref(db, dnh);
1337 mutex_exit(&dn->dn_mtx);
1338
1339 /* Now we can rely on the hold to prevent the dnode from moving. */
1340 zrl_remove(&dnh->dnh_zrlock);
1341
1342 DNODE_VERIFY(dn);
1343 ASSERT3P(dn->dn_dbuf, ==, db);
1344 ASSERT3U(dn->dn_object, ==, object);
1345 dbuf_rele(db, FTAG);
1346
1347 *dnp = dn;
1348 return (0);
1349 }
1350
1351 /*
1352 * Return held dnode if the object is allocated, NULL if not.
1353 */
1354 int
dnode_hold(objset_t * os,uint64_t object,void * tag,dnode_t ** dnp)1355 dnode_hold(objset_t *os, uint64_t object, void *tag, dnode_t **dnp)
1356 {
1357 return (dnode_hold_impl(os, object, DNODE_MUST_BE_ALLOCATED, 0, tag,
1358 dnp));
1359 }
1360
1361 /*
1362 * Can only add a reference if there is already at least one
1363 * reference on the dnode. Returns FALSE if unable to add a
1364 * new reference.
1365 */
1366 boolean_t
dnode_add_ref(dnode_t * dn,void * tag)1367 dnode_add_ref(dnode_t *dn, void *tag)
1368 {
1369 mutex_enter(&dn->dn_mtx);
1370 if (refcount_is_zero(&dn->dn_holds)) {
1371 mutex_exit(&dn->dn_mtx);
1372 return (FALSE);
1373 }
1374 VERIFY(1 < refcount_add(&dn->dn_holds, tag));
1375 mutex_exit(&dn->dn_mtx);
1376 return (TRUE);
1377 }
1378
1379 void
dnode_rele(dnode_t * dn,void * tag)1380 dnode_rele(dnode_t *dn, void *tag)
1381 {
1382 mutex_enter(&dn->dn_mtx);
1383 dnode_rele_and_unlock(dn, tag, B_FALSE);
1384 }
1385
1386 void
dnode_rele_and_unlock(dnode_t * dn,void * tag,boolean_t evicting)1387 dnode_rele_and_unlock(dnode_t *dn, void *tag, boolean_t evicting)
1388 {
1389 uint64_t refs;
1390 /* Get while the hold prevents the dnode from moving. */
1391 dmu_buf_impl_t *db = dn->dn_dbuf;
1392 dnode_handle_t *dnh = dn->dn_handle;
1393
1394 refs = refcount_remove(&dn->dn_holds, tag);
1395 mutex_exit(&dn->dn_mtx);
1396
1397 /*
1398 * It's unsafe to release the last hold on a dnode by dnode_rele() or
1399 * indirectly by dbuf_rele() while relying on the dnode handle to
1400 * prevent the dnode from moving, since releasing the last hold could
1401 * result in the dnode's parent dbuf evicting its dnode handles. For
1402 * that reason anyone calling dnode_rele() or dbuf_rele() without some
1403 * other direct or indirect hold on the dnode must first drop the dnode
1404 * handle.
1405 */
1406 ASSERT(refs > 0 || dnh->dnh_zrlock.zr_owner != curthread);
1407
1408 /* NOTE: the DNODE_DNODE does not have a dn_dbuf */
1409 if (refs == 0 && db != NULL) {
1410 /*
1411 * Another thread could add a hold to the dnode handle in
1412 * dnode_hold_impl() while holding the parent dbuf. Since the
1413 * hold on the parent dbuf prevents the handle from being
1414 * destroyed, the hold on the handle is OK. We can't yet assert
1415 * that the handle has zero references, but that will be
1416 * asserted anyway when the handle gets destroyed.
1417 */
1418 mutex_enter(&db->db_mtx);
1419 dbuf_rele_and_unlock(db, dnh, evicting);
1420 }
1421 }
1422
1423 void
dnode_setdirty(dnode_t * dn,dmu_tx_t * tx)1424 dnode_setdirty(dnode_t *dn, dmu_tx_t *tx)
1425 {
1426 objset_t *os = dn->dn_objset;
1427 uint64_t txg = tx->tx_txg;
1428
1429 if (DMU_OBJECT_IS_SPECIAL(dn->dn_object)) {
1430 dsl_dataset_dirty(os->os_dsl_dataset, tx);
1431 return;
1432 }
1433
1434 DNODE_VERIFY(dn);
1435
1436 #ifdef ZFS_DEBUG
1437 mutex_enter(&dn->dn_mtx);
1438 ASSERT(dn->dn_phys->dn_type || dn->dn_allocated_txg);
1439 ASSERT(dn->dn_free_txg == 0 || dn->dn_free_txg >= txg);
1440 mutex_exit(&dn->dn_mtx);
1441 #endif
1442
1443 /*
1444 * Determine old uid/gid when necessary
1445 */
1446 dmu_objset_userquota_get_ids(dn, B_TRUE, tx);
1447
1448 multilist_t *dirtylist = os->os_dirty_dnodes[txg & TXG_MASK];
1449 multilist_sublist_t *mls = multilist_sublist_lock_obj(dirtylist, dn);
1450
1451 /*
1452 * If we are already marked dirty, we're done.
1453 */
1454 if (list_link_active(&dn->dn_dirty_link[txg & TXG_MASK])) {
1455 multilist_sublist_unlock(mls);
1456 return;
1457 }
1458
1459 ASSERT(!refcount_is_zero(&dn->dn_holds) ||
1460 !avl_is_empty(&dn->dn_dbufs));
1461 ASSERT(dn->dn_datablksz != 0);
1462 ASSERT0(dn->dn_next_bonuslen[txg&TXG_MASK]);
1463 ASSERT0(dn->dn_next_blksz[txg&TXG_MASK]);
1464 ASSERT0(dn->dn_next_bonustype[txg&TXG_MASK]);
1465
1466 dprintf_ds(os->os_dsl_dataset, "obj=%llu txg=%llu\n",
1467 dn->dn_object, txg);
1468
1469 multilist_sublist_insert_head(mls, dn);
1470
1471 multilist_sublist_unlock(mls);
1472
1473 /*
1474 * The dnode maintains a hold on its containing dbuf as
1475 * long as there are holds on it. Each instantiated child
1476 * dbuf maintains a hold on the dnode. When the last child
1477 * drops its hold, the dnode will drop its hold on the
1478 * containing dbuf. We add a "dirty hold" here so that the
1479 * dnode will hang around after we finish processing its
1480 * children.
1481 */
1482 VERIFY(dnode_add_ref(dn, (void *)(uintptr_t)tx->tx_txg));
1483
1484 (void) dbuf_dirty(dn->dn_dbuf, tx);
1485
1486 dsl_dataset_dirty(os->os_dsl_dataset, tx);
1487 }
1488
1489 void
dnode_free(dnode_t * dn,dmu_tx_t * tx)1490 dnode_free(dnode_t *dn, dmu_tx_t *tx)
1491 {
1492 mutex_enter(&dn->dn_mtx);
1493 if (dn->dn_type == DMU_OT_NONE || dn->dn_free_txg) {
1494 mutex_exit(&dn->dn_mtx);
1495 return;
1496 }
1497 dn->dn_free_txg = tx->tx_txg;
1498 mutex_exit(&dn->dn_mtx);
1499
1500 dnode_setdirty(dn, tx);
1501 }
1502
1503 /*
1504 * Try to change the block size for the indicated dnode. This can only
1505 * succeed if there are no blocks allocated or dirty beyond first block
1506 */
1507 int
dnode_set_blksz(dnode_t * dn,uint64_t size,int ibs,dmu_tx_t * tx)1508 dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx)
1509 {
1510 dmu_buf_impl_t *db;
1511 int err;
1512
1513 ASSERT3U(size, <=, spa_maxblocksize(dmu_objset_spa(dn->dn_objset)));
1514 if (size == 0)
1515 size = SPA_MINBLOCKSIZE;
1516 else
1517 size = P2ROUNDUP(size, SPA_MINBLOCKSIZE);
1518
1519 if (ibs == dn->dn_indblkshift)
1520 ibs = 0;
1521
1522 if (size >> SPA_MINBLOCKSHIFT == dn->dn_datablkszsec && ibs == 0)
1523 return (0);
1524
1525 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
1526
1527 /* Check for any allocated blocks beyond the first */
1528 if (dn->dn_maxblkid != 0)
1529 goto fail;
1530
1531 mutex_enter(&dn->dn_dbufs_mtx);
1532 for (db = avl_first(&dn->dn_dbufs); db != NULL;
1533 db = AVL_NEXT(&dn->dn_dbufs, db)) {
1534 if (db->db_blkid != 0 && db->db_blkid != DMU_BONUS_BLKID &&
1535 db->db_blkid != DMU_SPILL_BLKID) {
1536 mutex_exit(&dn->dn_dbufs_mtx);
1537 goto fail;
1538 }
1539 }
1540 mutex_exit(&dn->dn_dbufs_mtx);
1541
1542 if (ibs && dn->dn_nlevels != 1)
1543 goto fail;
1544
1545 /* resize the old block */
1546 err = dbuf_hold_impl(dn, 0, 0, TRUE, FALSE, FTAG, &db);
1547 if (err == 0)
1548 dbuf_new_size(db, size, tx);
1549 else if (err != ENOENT)
1550 goto fail;
1551
1552 dnode_setdblksz(dn, size);
1553 dnode_setdirty(dn, tx);
1554 dn->dn_next_blksz[tx->tx_txg&TXG_MASK] = size;
1555 if (ibs) {
1556 dn->dn_indblkshift = ibs;
1557 dn->dn_next_indblkshift[tx->tx_txg&TXG_MASK] = ibs;
1558 }
1559 /* rele after we have fixed the blocksize in the dnode */
1560 if (db)
1561 dbuf_rele(db, FTAG);
1562
1563 rw_exit(&dn->dn_struct_rwlock);
1564 return (0);
1565
1566 fail:
1567 rw_exit(&dn->dn_struct_rwlock);
1568 return (SET_ERROR(ENOTSUP));
1569 }
1570
1571 /* read-holding callers must not rely on the lock being continuously held */
1572 void
dnode_new_blkid(dnode_t * dn,uint64_t blkid,dmu_tx_t * tx,boolean_t have_read)1573 dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx, boolean_t have_read)
1574 {
1575 uint64_t txgoff = tx->tx_txg & TXG_MASK;
1576 int epbs, new_nlevels;
1577 uint64_t sz;
1578
1579 ASSERT(blkid != DMU_BONUS_BLKID);
1580
1581 ASSERT(have_read ?
1582 RW_READ_HELD(&dn->dn_struct_rwlock) :
1583 RW_WRITE_HELD(&dn->dn_struct_rwlock));
1584
1585 /*
1586 * if we have a read-lock, check to see if we need to do any work
1587 * before upgrading to a write-lock.
1588 */
1589 if (have_read) {
1590 if (blkid <= dn->dn_maxblkid)
1591 return;
1592
1593 if (!rw_tryupgrade(&dn->dn_struct_rwlock)) {
1594 rw_exit(&dn->dn_struct_rwlock);
1595 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
1596 }
1597 }
1598
1599 if (blkid <= dn->dn_maxblkid)
1600 goto out;
1601
1602 dn->dn_maxblkid = blkid;
1603
1604 /*
1605 * Compute the number of levels necessary to support the new maxblkid.
1606 */
1607 new_nlevels = 1;
1608 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1609 for (sz = dn->dn_nblkptr;
1610 sz <= blkid && sz >= dn->dn_nblkptr; sz <<= epbs)
1611 new_nlevels++;
1612
1613 if (new_nlevels > dn->dn_nlevels) {
1614 int old_nlevels = dn->dn_nlevels;
1615 dmu_buf_impl_t *db;
1616 list_t *list;
1617 dbuf_dirty_record_t *new, *dr, *dr_next;
1618
1619 dn->dn_nlevels = new_nlevels;
1620
1621 ASSERT3U(new_nlevels, >, dn->dn_next_nlevels[txgoff]);
1622 dn->dn_next_nlevels[txgoff] = new_nlevels;
1623
1624 /* dirty the left indirects */
1625 db = dbuf_hold_level(dn, old_nlevels, 0, FTAG);
1626 ASSERT(db != NULL);
1627 new = dbuf_dirty(db, tx);
1628 dbuf_rele(db, FTAG);
1629
1630 /* transfer the dirty records to the new indirect */
1631 mutex_enter(&dn->dn_mtx);
1632 mutex_enter(&new->dt.di.dr_mtx);
1633 list = &dn->dn_dirty_records[txgoff];
1634 for (dr = list_head(list); dr; dr = dr_next) {
1635 dr_next = list_next(&dn->dn_dirty_records[txgoff], dr);
1636 if (dr->dr_dbuf->db_level != new_nlevels-1 &&
1637 dr->dr_dbuf->db_blkid != DMU_BONUS_BLKID &&
1638 dr->dr_dbuf->db_blkid != DMU_SPILL_BLKID) {
1639 ASSERT(dr->dr_dbuf->db_level == old_nlevels-1);
1640 list_remove(&dn->dn_dirty_records[txgoff], dr);
1641 list_insert_tail(&new->dt.di.dr_children, dr);
1642 dr->dr_parent = new;
1643 }
1644 }
1645 mutex_exit(&new->dt.di.dr_mtx);
1646 mutex_exit(&dn->dn_mtx);
1647 }
1648
1649 out:
1650 if (have_read)
1651 rw_downgrade(&dn->dn_struct_rwlock);
1652 }
1653
1654 static void
dnode_dirty_l1(dnode_t * dn,uint64_t l1blkid,dmu_tx_t * tx)1655 dnode_dirty_l1(dnode_t *dn, uint64_t l1blkid, dmu_tx_t *tx)
1656 {
1657 dmu_buf_impl_t *db = dbuf_hold_level(dn, 1, l1blkid, FTAG);
1658 if (db != NULL) {
1659 dmu_buf_will_dirty(&db->db, tx);
1660 dbuf_rele(db, FTAG);
1661 }
1662 }
1663
1664 /*
1665 * Dirty all the in-core level-1 dbufs in the range specified by start_blkid
1666 * and end_blkid.
1667 */
1668 static void
dnode_dirty_l1range(dnode_t * dn,uint64_t start_blkid,uint64_t end_blkid,dmu_tx_t * tx)1669 dnode_dirty_l1range(dnode_t *dn, uint64_t start_blkid, uint64_t end_blkid,
1670 dmu_tx_t *tx)
1671 {
1672 dmu_buf_impl_t db_search;
1673 dmu_buf_impl_t *db;
1674 avl_index_t where;
1675
1676 mutex_enter(&dn->dn_dbufs_mtx);
1677
1678 db_search.db_level = 1;
1679 db_search.db_blkid = start_blkid + 1;
1680 db_search.db_state = DB_SEARCH;
1681 for (;;) {
1682
1683 db = avl_find(&dn->dn_dbufs, &db_search, &where);
1684 if (db == NULL)
1685 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER);
1686
1687 if (db == NULL || db->db_level != 1 ||
1688 db->db_blkid >= end_blkid) {
1689 break;
1690 }
1691
1692 /*
1693 * Setup the next blkid we want to search for.
1694 */
1695 db_search.db_blkid = db->db_blkid + 1;
1696 ASSERT3U(db->db_blkid, >=, start_blkid);
1697
1698 /*
1699 * If the dbuf transitions to DB_EVICTING while we're trying
1700 * to dirty it, then we will be unable to discover it in
1701 * the dbuf hash table. This will result in a call to
1702 * dbuf_create() which needs to acquire the dn_dbufs_mtx
1703 * lock. To avoid a deadlock, we drop the lock before
1704 * dirtying the level-1 dbuf.
1705 */
1706 mutex_exit(&dn->dn_dbufs_mtx);
1707 dnode_dirty_l1(dn, db->db_blkid, tx);
1708 mutex_enter(&dn->dn_dbufs_mtx);
1709 }
1710
1711 #ifdef ZFS_DEBUG
1712 /*
1713 * Walk all the in-core level-1 dbufs and verify they have been dirtied.
1714 */
1715 db_search.db_level = 1;
1716 db_search.db_blkid = start_blkid + 1;
1717 db_search.db_state = DB_SEARCH;
1718 db = avl_find(&dn->dn_dbufs, &db_search, &where);
1719 if (db == NULL)
1720 db = avl_nearest(&dn->dn_dbufs, where, AVL_AFTER);
1721 for (; db != NULL; db = AVL_NEXT(&dn->dn_dbufs, db)) {
1722 if (db->db_level != 1 || db->db_blkid >= end_blkid)
1723 break;
1724 ASSERT(db->db_dirtycnt > 0);
1725 }
1726 #endif
1727 mutex_exit(&dn->dn_dbufs_mtx);
1728 }
1729
1730 void
dnode_free_range(dnode_t * dn,uint64_t off,uint64_t len,dmu_tx_t * tx)1731 dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx)
1732 {
1733 dmu_buf_impl_t *db;
1734 uint64_t blkoff, blkid, nblks;
1735 int blksz, blkshift, head, tail;
1736 int trunc = FALSE;
1737 int epbs;
1738
1739 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
1740 blksz = dn->dn_datablksz;
1741 blkshift = dn->dn_datablkshift;
1742 epbs = dn->dn_indblkshift - SPA_BLKPTRSHIFT;
1743
1744 if (len == DMU_OBJECT_END) {
1745 len = UINT64_MAX - off;
1746 trunc = TRUE;
1747 }
1748
1749 /*
1750 * First, block align the region to free:
1751 */
1752 if (ISP2(blksz)) {
1753 head = P2NPHASE(off, blksz);
1754 blkoff = P2PHASE(off, blksz);
1755 if ((off >> blkshift) > dn->dn_maxblkid)
1756 goto out;
1757 } else {
1758 ASSERT(dn->dn_maxblkid == 0);
1759 if (off == 0 && len >= blksz) {
1760 /*
1761 * Freeing the whole block; fast-track this request.
1762 */
1763 blkid = 0;
1764 nblks = 1;
1765 if (dn->dn_nlevels > 1)
1766 dnode_dirty_l1(dn, 0, tx);
1767 goto done;
1768 } else if (off >= blksz) {
1769 /* Freeing past end-of-data */
1770 goto out;
1771 } else {
1772 /* Freeing part of the block. */
1773 head = blksz - off;
1774 ASSERT3U(head, >, 0);
1775 }
1776 blkoff = off;
1777 }
1778 /* zero out any partial block data at the start of the range */
1779 if (head) {
1780 ASSERT3U(blkoff + head, ==, blksz);
1781 if (len < head)
1782 head = len;
1783 if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off),
1784 TRUE, FALSE, FTAG, &db) == 0) {
1785 caddr_t data;
1786
1787 /* don't dirty if it isn't on disk and isn't dirty */
1788 if (db->db_last_dirty ||
1789 (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) {
1790 rw_exit(&dn->dn_struct_rwlock);
1791 dmu_buf_will_dirty(&db->db, tx);
1792 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
1793 data = db->db.db_data;
1794 bzero(data + blkoff, head);
1795 }
1796 dbuf_rele(db, FTAG);
1797 }
1798 off += head;
1799 len -= head;
1800 }
1801
1802 /* If the range was less than one block, we're done */
1803 if (len == 0)
1804 goto out;
1805
1806 /* If the remaining range is past end of file, we're done */
1807 if ((off >> blkshift) > dn->dn_maxblkid)
1808 goto out;
1809
1810 ASSERT(ISP2(blksz));
1811 if (trunc)
1812 tail = 0;
1813 else
1814 tail = P2PHASE(len, blksz);
1815
1816 ASSERT0(P2PHASE(off, blksz));
1817 /* zero out any partial block data at the end of the range */
1818 if (tail) {
1819 if (len < tail)
1820 tail = len;
1821 if (dbuf_hold_impl(dn, 0, dbuf_whichblock(dn, 0, off+len),
1822 TRUE, FALSE, FTAG, &db) == 0) {
1823 /* don't dirty if not on disk and not dirty */
1824 if (db->db_last_dirty ||
1825 (db->db_blkptr && !BP_IS_HOLE(db->db_blkptr))) {
1826 rw_exit(&dn->dn_struct_rwlock);
1827 dmu_buf_will_dirty(&db->db, tx);
1828 rw_enter(&dn->dn_struct_rwlock, RW_WRITER);
1829 bzero(db->db.db_data, tail);
1830 }
1831 dbuf_rele(db, FTAG);
1832 }
1833 len -= tail;
1834 }
1835
1836 /* If the range did not include a full block, we are done */
1837 if (len == 0)
1838 goto out;
1839
1840 ASSERT(IS_P2ALIGNED(off, blksz));
1841 ASSERT(trunc || IS_P2ALIGNED(len, blksz));
1842 blkid = off >> blkshift;
1843 nblks = len >> blkshift;
1844 if (trunc)
1845 nblks += 1;
1846
1847 /*
1848 * Dirty all the indirect blocks in this range. Note that only
1849 * the first and last indirect blocks can actually be written
1850 * (if they were partially freed) -- they must be dirtied, even if
1851 * they do not exist on disk yet. The interior blocks will
1852 * be freed by free_children(), so they will not actually be written.
1853 * Even though these interior blocks will not be written, we
1854 * dirty them for two reasons:
1855 *
1856 * - It ensures that the indirect blocks remain in memory until
1857 * syncing context. (They have already been prefetched by
1858 * dmu_tx_hold_free(), so we don't have to worry about reading
1859 * them serially here.)
1860 *
1861 * - The dirty space accounting will put pressure on the txg sync
1862 * mechanism to begin syncing, and to delay transactions if there
1863 * is a large amount of freeing. Even though these indirect
1864 * blocks will not be written, we could need to write the same
1865 * amount of space if we copy the freed BPs into deadlists.
1866 */
1867 if (dn->dn_nlevels > 1) {
1868 uint64_t first, last;
1869
1870 first = blkid >> epbs;
1871 dnode_dirty_l1(dn, first, tx);
1872 if (trunc)
1873 last = dn->dn_maxblkid >> epbs;
1874 else
1875 last = (blkid + nblks - 1) >> epbs;
1876 if (last != first)
1877 dnode_dirty_l1(dn, last, tx);
1878
1879 dnode_dirty_l1range(dn, first, last, tx);
1880
1881 int shift = dn->dn_datablkshift + dn->dn_indblkshift -
1882 SPA_BLKPTRSHIFT;
1883 for (uint64_t i = first + 1; i < last; i++) {
1884 /*
1885 * Set i to the blockid of the next non-hole
1886 * level-1 indirect block at or after i. Note
1887 * that dnode_next_offset() operates in terms of
1888 * level-0-equivalent bytes.
1889 */
1890 uint64_t ibyte = i << shift;
1891 int err = dnode_next_offset(dn, DNODE_FIND_HAVELOCK,
1892 &ibyte, 2, 1, 0);
1893 i = ibyte >> shift;
1894 if (i >= last)
1895 break;
1896
1897 /*
1898 * Normally we should not see an error, either
1899 * from dnode_next_offset() or dbuf_hold_level()
1900 * (except for ESRCH from dnode_next_offset).
1901 * If there is an i/o error, then when we read
1902 * this block in syncing context, it will use
1903 * ZIO_FLAG_MUSTSUCCEED, and thus hang/panic according
1904 * to the "failmode" property. dnode_next_offset()
1905 * doesn't have a flag to indicate MUSTSUCCEED.
1906 */
1907 if (err != 0)
1908 break;
1909
1910 dnode_dirty_l1(dn, i, tx);
1911 }
1912 }
1913
1914 done:
1915 /*
1916 * Add this range to the dnode range list.
1917 * We will finish up this free operation in the syncing phase.
1918 */
1919 mutex_enter(&dn->dn_mtx);
1920 int txgoff = tx->tx_txg & TXG_MASK;
1921 if (dn->dn_free_ranges[txgoff] == NULL) {
1922 dn->dn_free_ranges[txgoff] = range_tree_create(NULL, NULL);
1923 }
1924 range_tree_clear(dn->dn_free_ranges[txgoff], blkid, nblks);
1925 range_tree_add(dn->dn_free_ranges[txgoff], blkid, nblks);
1926 dprintf_dnode(dn, "blkid=%llu nblks=%llu txg=%llu\n",
1927 blkid, nblks, tx->tx_txg);
1928 mutex_exit(&dn->dn_mtx);
1929
1930 dbuf_free_range(dn, blkid, blkid + nblks - 1, tx);
1931 dnode_setdirty(dn, tx);
1932 out:
1933
1934 rw_exit(&dn->dn_struct_rwlock);
1935 }
1936
1937 static boolean_t
dnode_spill_freed(dnode_t * dn)1938 dnode_spill_freed(dnode_t *dn)
1939 {
1940 int i;
1941
1942 mutex_enter(&dn->dn_mtx);
1943 for (i = 0; i < TXG_SIZE; i++) {
1944 if (dn->dn_rm_spillblk[i] == DN_KILL_SPILLBLK)
1945 break;
1946 }
1947 mutex_exit(&dn->dn_mtx);
1948 return (i < TXG_SIZE);
1949 }
1950
1951 /* return TRUE if this blkid was freed in a recent txg, or FALSE if it wasn't */
1952 uint64_t
dnode_block_freed(dnode_t * dn,uint64_t blkid)1953 dnode_block_freed(dnode_t *dn, uint64_t blkid)
1954 {
1955 void *dp = spa_get_dsl(dn->dn_objset->os_spa);
1956 int i;
1957
1958 if (blkid == DMU_BONUS_BLKID)
1959 return (FALSE);
1960
1961 /*
1962 * If we're in the process of opening the pool, dp will not be
1963 * set yet, but there shouldn't be anything dirty.
1964 */
1965 if (dp == NULL)
1966 return (FALSE);
1967
1968 if (dn->dn_free_txg)
1969 return (TRUE);
1970
1971 if (blkid == DMU_SPILL_BLKID)
1972 return (dnode_spill_freed(dn));
1973
1974 mutex_enter(&dn->dn_mtx);
1975 for (i = 0; i < TXG_SIZE; i++) {
1976 if (dn->dn_free_ranges[i] != NULL &&
1977 range_tree_contains(dn->dn_free_ranges[i], blkid, 1))
1978 break;
1979 }
1980 mutex_exit(&dn->dn_mtx);
1981 return (i < TXG_SIZE);
1982 }
1983
1984 /* call from syncing context when we actually write/free space for this dnode */
1985 void
dnode_diduse_space(dnode_t * dn,int64_t delta)1986 dnode_diduse_space(dnode_t *dn, int64_t delta)
1987 {
1988 uint64_t space;
1989 dprintf_dnode(dn, "dn=%p dnp=%p used=%llu delta=%lld\n",
1990 dn, dn->dn_phys,
1991 (u_longlong_t)dn->dn_phys->dn_used,
1992 (longlong_t)delta);
1993
1994 mutex_enter(&dn->dn_mtx);
1995 space = DN_USED_BYTES(dn->dn_phys);
1996 if (delta > 0) {
1997 ASSERT3U(space + delta, >=, space); /* no overflow */
1998 } else {
1999 ASSERT3U(space, >=, -delta); /* no underflow */
2000 }
2001 space += delta;
2002 if (spa_version(dn->dn_objset->os_spa) < SPA_VERSION_DNODE_BYTES) {
2003 ASSERT((dn->dn_phys->dn_flags & DNODE_FLAG_USED_BYTES) == 0);
2004 ASSERT0(P2PHASE(space, 1<<DEV_BSHIFT));
2005 dn->dn_phys->dn_used = space >> DEV_BSHIFT;
2006 } else {
2007 dn->dn_phys->dn_used = space;
2008 dn->dn_phys->dn_flags |= DNODE_FLAG_USED_BYTES;
2009 }
2010 mutex_exit(&dn->dn_mtx);
2011 }
2012
2013 /*
2014 * Scans a block at the indicated "level" looking for a hole or data,
2015 * depending on 'flags'.
2016 *
2017 * If level > 0, then we are scanning an indirect block looking at its
2018 * pointers. If level == 0, then we are looking at a block of dnodes.
2019 *
2020 * If we don't find what we are looking for in the block, we return ESRCH.
2021 * Otherwise, return with *offset pointing to the beginning (if searching
2022 * forwards) or end (if searching backwards) of the range covered by the
2023 * block pointer we matched on (or dnode).
2024 *
2025 * The basic search algorithm used below by dnode_next_offset() is to
2026 * use this function to search up the block tree (widen the search) until
2027 * we find something (i.e., we don't return ESRCH) and then search back
2028 * down the tree (narrow the search) until we reach our original search
2029 * level.
2030 */
2031 static int
dnode_next_offset_level(dnode_t * dn,int flags,uint64_t * offset,int lvl,uint64_t blkfill,uint64_t txg)2032 dnode_next_offset_level(dnode_t *dn, int flags, uint64_t *offset,
2033 int lvl, uint64_t blkfill, uint64_t txg)
2034 {
2035 dmu_buf_impl_t *db = NULL;
2036 void *data = NULL;
2037 uint64_t epbs = dn->dn_phys->dn_indblkshift - SPA_BLKPTRSHIFT;
2038 uint64_t epb = 1ULL << epbs;
2039 uint64_t minfill, maxfill;
2040 boolean_t hole;
2041 int i, inc, error, span;
2042
2043 dprintf("probing object %llu offset %llx level %d of %u\n",
2044 dn->dn_object, *offset, lvl, dn->dn_phys->dn_nlevels);
2045
2046 hole = ((flags & DNODE_FIND_HOLE) != 0);
2047 inc = (flags & DNODE_FIND_BACKWARDS) ? -1 : 1;
2048 ASSERT(txg == 0 || !hole);
2049
2050 if (lvl == dn->dn_phys->dn_nlevels) {
2051 error = 0;
2052 epb = dn->dn_phys->dn_nblkptr;
2053 data = dn->dn_phys->dn_blkptr;
2054 } else {
2055 uint64_t blkid = dbuf_whichblock(dn, lvl, *offset);
2056 error = dbuf_hold_impl(dn, lvl, blkid, TRUE, FALSE, FTAG, &db);
2057 if (error) {
2058 if (error != ENOENT)
2059 return (error);
2060 if (hole)
2061 return (0);
2062 /*
2063 * This can only happen when we are searching up
2064 * the block tree for data. We don't really need to
2065 * adjust the offset, as we will just end up looking
2066 * at the pointer to this block in its parent, and its
2067 * going to be unallocated, so we will skip over it.
2068 */
2069 return (SET_ERROR(ESRCH));
2070 }
2071 error = dbuf_read(db, NULL, DB_RF_CANFAIL | DB_RF_HAVESTRUCT);
2072 if (error) {
2073 dbuf_rele(db, FTAG);
2074 return (error);
2075 }
2076 data = db->db.db_data;
2077 }
2078
2079
2080 if (db != NULL && txg != 0 && (db->db_blkptr == NULL ||
2081 db->db_blkptr->blk_birth <= txg ||
2082 BP_IS_HOLE(db->db_blkptr))) {
2083 /*
2084 * This can only happen when we are searching up the tree
2085 * and these conditions mean that we need to keep climbing.
2086 */
2087 error = SET_ERROR(ESRCH);
2088 } else if (lvl == 0) {
2089 dnode_phys_t *dnp = data;
2090
2091 ASSERT(dn->dn_type == DMU_OT_DNODE);
2092 ASSERT(!(flags & DNODE_FIND_BACKWARDS));
2093
2094 for (i = (*offset >> DNODE_SHIFT) & (blkfill - 1);
2095 i < blkfill; i += dnp[i].dn_extra_slots + 1) {
2096 if ((dnp[i].dn_type == DMU_OT_NONE) == hole)
2097 break;
2098 }
2099
2100 if (i == blkfill)
2101 error = SET_ERROR(ESRCH);
2102
2103 *offset = (*offset & ~(DNODE_BLOCK_SIZE - 1)) +
2104 (i << DNODE_SHIFT);
2105 } else {
2106 blkptr_t *bp = data;
2107 uint64_t start = *offset;
2108 span = (lvl - 1) * epbs + dn->dn_datablkshift;
2109 minfill = 0;
2110 maxfill = blkfill << ((lvl - 1) * epbs);
2111
2112 if (hole)
2113 maxfill--;
2114 else
2115 minfill++;
2116
2117 *offset = *offset >> span;
2118 for (i = BF64_GET(*offset, 0, epbs);
2119 i >= 0 && i < epb; i += inc) {
2120 if (BP_GET_FILL(&bp[i]) >= minfill &&
2121 BP_GET_FILL(&bp[i]) <= maxfill &&
2122 (hole || bp[i].blk_birth > txg))
2123 break;
2124 if (inc > 0 || *offset > 0)
2125 *offset += inc;
2126 }
2127 *offset = *offset << span;
2128 if (inc < 0) {
2129 /* traversing backwards; position offset at the end */
2130 ASSERT3U(*offset, <=, start);
2131 *offset = MIN(*offset + (1ULL << span) - 1, start);
2132 } else if (*offset < start) {
2133 *offset = start;
2134 }
2135 if (i < 0 || i >= epb)
2136 error = SET_ERROR(ESRCH);
2137 }
2138
2139 if (db)
2140 dbuf_rele(db, FTAG);
2141
2142 return (error);
2143 }
2144
2145 /*
2146 * Find the next hole, data, or sparse region at or after *offset.
2147 * The value 'blkfill' tells us how many items we expect to find
2148 * in an L0 data block; this value is 1 for normal objects,
2149 * DNODES_PER_BLOCK for the meta dnode, and some fraction of
2150 * DNODES_PER_BLOCK when searching for sparse regions thereof.
2151 *
2152 * Examples:
2153 *
2154 * dnode_next_offset(dn, flags, offset, 1, 1, 0);
2155 * Finds the next/previous hole/data in a file.
2156 * Used in dmu_offset_next().
2157 *
2158 * dnode_next_offset(mdn, flags, offset, 0, DNODES_PER_BLOCK, txg);
2159 * Finds the next free/allocated dnode an objset's meta-dnode.
2160 * Only finds objects that have new contents since txg (ie.
2161 * bonus buffer changes and content removal are ignored).
2162 * Used in dmu_object_next().
2163 *
2164 * dnode_next_offset(mdn, DNODE_FIND_HOLE, offset, 2, DNODES_PER_BLOCK >> 2, 0);
2165 * Finds the next L2 meta-dnode bp that's at most 1/4 full.
2166 * Used in dmu_object_alloc().
2167 */
2168 int
dnode_next_offset(dnode_t * dn,int flags,uint64_t * offset,int minlvl,uint64_t blkfill,uint64_t txg)2169 dnode_next_offset(dnode_t *dn, int flags, uint64_t *offset,
2170 int minlvl, uint64_t blkfill, uint64_t txg)
2171 {
2172 uint64_t initial_offset = *offset;
2173 int lvl, maxlvl;
2174 int error = 0;
2175
2176 if (!(flags & DNODE_FIND_HAVELOCK))
2177 rw_enter(&dn->dn_struct_rwlock, RW_READER);
2178
2179 if (dn->dn_phys->dn_nlevels == 0) {
2180 error = SET_ERROR(ESRCH);
2181 goto out;
2182 }
2183
2184 if (dn->dn_datablkshift == 0) {
2185 if (*offset < dn->dn_datablksz) {
2186 if (flags & DNODE_FIND_HOLE)
2187 *offset = dn->dn_datablksz;
2188 } else {
2189 error = SET_ERROR(ESRCH);
2190 }
2191 goto out;
2192 }
2193
2194 maxlvl = dn->dn_phys->dn_nlevels;
2195
2196 for (lvl = minlvl; lvl <= maxlvl; lvl++) {
2197 error = dnode_next_offset_level(dn,
2198 flags, offset, lvl, blkfill, txg);
2199 if (error != ESRCH)
2200 break;
2201 }
2202
2203 while (error == 0 && --lvl >= minlvl) {
2204 error = dnode_next_offset_level(dn,
2205 flags, offset, lvl, blkfill, txg);
2206 }
2207
2208 /*
2209 * There's always a "virtual hole" at the end of the object, even
2210 * if all BP's which physically exist are non-holes.
2211 */
2212 if ((flags & DNODE_FIND_HOLE) && error == ESRCH && txg == 0 &&
2213 minlvl == 1 && blkfill == 1 && !(flags & DNODE_FIND_BACKWARDS)) {
2214 error = 0;
2215 }
2216
2217 if (error == 0 && (flags & DNODE_FIND_BACKWARDS ?
2218 initial_offset < *offset : initial_offset > *offset))
2219 error = SET_ERROR(ESRCH);
2220 out:
2221 if (!(flags & DNODE_FIND_HAVELOCK))
2222 rw_exit(&dn->dn_struct_rwlock);
2223
2224 return (error);
2225 }
2226