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.
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.
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]
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
24 * Copyright (c) 2012, 2017 by Delphix. All rights reserved.
25 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
26 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
29 #include <sys/zfs_context.h>
32 #include <sys/dmu_send.h>
33 #include <sys/dmu_impl.h>
35 #include <sys/dmu_objset.h>
36 #include <sys/dsl_dataset.h>
37 #include <sys/dsl_dir.h>
38 #include <sys/dmu_tx.h>
41 #include <sys/dmu_zfetch.h>
43 #include <sys/sa_impl.h>
44 #include <sys/zfeature.h>
45 #include <sys/blkptr.h>
46 #include <sys/range_tree.h>
47 #include <sys/trace_dbuf.h>
48 #include <sys/callb.h>
53 typedef struct dbuf_stats
{
55 * Various statistics about the size of the dbuf cache.
57 kstat_named_t cache_count
;
58 kstat_named_t cache_size_bytes
;
59 kstat_named_t cache_size_bytes_max
;
61 * Statistics regarding the bounds on the dbuf cache size.
63 kstat_named_t cache_target_bytes
;
64 kstat_named_t cache_lowater_bytes
;
65 kstat_named_t cache_hiwater_bytes
;
67 * Total number of dbuf cache evictions that have occurred.
69 kstat_named_t cache_total_evicts
;
71 * The distribution of dbuf levels in the dbuf cache and
72 * the total size of all dbufs at each level.
74 kstat_named_t cache_levels
[DN_MAX_LEVELS
];
75 kstat_named_t cache_levels_bytes
[DN_MAX_LEVELS
];
77 * Statistics about the dbuf hash table.
79 kstat_named_t hash_hits
;
80 kstat_named_t hash_misses
;
81 kstat_named_t hash_collisions
;
82 kstat_named_t hash_elements
;
83 kstat_named_t hash_elements_max
;
85 * Number of sublists containing more than one dbuf in the dbuf
86 * hash table. Keep track of the longest hash chain.
88 kstat_named_t hash_chains
;
89 kstat_named_t hash_chain_max
;
91 * Number of times a dbuf_create() discovers that a dbuf was
92 * already created and in the dbuf hash table.
94 kstat_named_t hash_insert_race
;
97 dbuf_stats_t dbuf_stats
= {
98 { "cache_count", KSTAT_DATA_UINT64
},
99 { "cache_size_bytes", KSTAT_DATA_UINT64
},
100 { "cache_size_bytes_max", KSTAT_DATA_UINT64
},
101 { "cache_target_bytes", KSTAT_DATA_UINT64
},
102 { "cache_lowater_bytes", KSTAT_DATA_UINT64
},
103 { "cache_hiwater_bytes", KSTAT_DATA_UINT64
},
104 { "cache_total_evicts", KSTAT_DATA_UINT64
},
105 { { "cache_levels_N", KSTAT_DATA_UINT64
} },
106 { { "cache_levels_bytes_N", KSTAT_DATA_UINT64
} },
107 { "hash_hits", KSTAT_DATA_UINT64
},
108 { "hash_misses", KSTAT_DATA_UINT64
},
109 { "hash_collisions", KSTAT_DATA_UINT64
},
110 { "hash_elements", KSTAT_DATA_UINT64
},
111 { "hash_elements_max", KSTAT_DATA_UINT64
},
112 { "hash_chains", KSTAT_DATA_UINT64
},
113 { "hash_chain_max", KSTAT_DATA_UINT64
},
114 { "hash_insert_race", KSTAT_DATA_UINT64
}
117 #define DBUF_STAT_INCR(stat, val) \
118 atomic_add_64(&dbuf_stats.stat.value.ui64, (val));
119 #define DBUF_STAT_DECR(stat, val) \
120 DBUF_STAT_INCR(stat, -(val));
121 #define DBUF_STAT_BUMP(stat) \
122 DBUF_STAT_INCR(stat, 1);
123 #define DBUF_STAT_BUMPDOWN(stat) \
124 DBUF_STAT_INCR(stat, -1);
125 #define DBUF_STAT_MAX(stat, v) { \
127 while ((v) > (_m = dbuf_stats.stat.value.ui64) && \
128 (_m != atomic_cas_64(&dbuf_stats.stat.value.ui64, _m, (v))))\
132 struct dbuf_hold_impl_data
{
133 /* Function arguments */
137 boolean_t dh_fail_sparse
;
138 boolean_t dh_fail_uncached
;
140 dmu_buf_impl_t
**dh_dbp
;
141 /* Local variables */
142 dmu_buf_impl_t
*dh_db
;
143 dmu_buf_impl_t
*dh_parent
;
146 dbuf_dirty_record_t
*dh_dr
;
150 static void __dbuf_hold_impl_init(struct dbuf_hold_impl_data
*dh
,
151 dnode_t
*dn
, uint8_t level
, uint64_t blkid
, boolean_t fail_sparse
,
152 boolean_t fail_uncached
,
153 void *tag
, dmu_buf_impl_t
**dbp
, int depth
);
154 static int __dbuf_hold_impl(struct dbuf_hold_impl_data
*dh
);
156 uint_t zfs_dbuf_evict_key
;
158 static boolean_t
dbuf_undirty(dmu_buf_impl_t
*db
, dmu_tx_t
*tx
);
159 static void dbuf_write(dbuf_dirty_record_t
*dr
, arc_buf_t
*data
, dmu_tx_t
*tx
);
161 extern inline void dmu_buf_init_user(dmu_buf_user_t
*dbu
,
162 dmu_buf_evict_func_t
*evict_func_sync
,
163 dmu_buf_evict_func_t
*evict_func_async
,
164 dmu_buf_t
**clear_on_evict_dbufp
);
167 * Global data structures and functions for the dbuf cache.
169 static kmem_cache_t
*dbuf_kmem_cache
;
170 static taskq_t
*dbu_evict_taskq
;
172 static kthread_t
*dbuf_cache_evict_thread
;
173 static kmutex_t dbuf_evict_lock
;
174 static kcondvar_t dbuf_evict_cv
;
175 static boolean_t dbuf_evict_thread_exit
;
178 * LRU cache of dbufs. The dbuf cache maintains a list of dbufs that
179 * are not currently held but have been recently released. These dbufs
180 * are not eligible for arc eviction until they are aged out of the cache.
181 * Dbufs are added to the dbuf cache once the last hold is released. If a
182 * dbuf is later accessed and still exists in the dbuf cache, then it will
183 * be removed from the cache and later re-added to the head of the cache.
184 * Dbufs that are aged out of the cache will be immediately destroyed and
185 * become eligible for arc eviction.
187 static multilist_t
*dbuf_cache
;
188 static refcount_t dbuf_cache_size
;
189 unsigned long dbuf_cache_max_bytes
= 100 * 1024 * 1024;
191 /* Cap the size of the dbuf cache to log2 fraction of arc size. */
192 int dbuf_cache_max_shift
= 5;
195 * The dbuf cache uses a three-stage eviction policy:
196 * - A low water marker designates when the dbuf eviction thread
197 * should stop evicting from the dbuf cache.
198 * - When we reach the maximum size (aka mid water mark), we
199 * signal the eviction thread to run.
200 * - The high water mark indicates when the eviction thread
201 * is unable to keep up with the incoming load and eviction must
202 * happen in the context of the calling thread.
206 * low water mid water hi water
207 * +----------------------------------------+----------+----------+
212 * +----------------------------------------+----------+----------+
214 * evicting eviction directly
217 * The high and low water marks indicate the operating range for the eviction
218 * thread. The low water mark is, by default, 90% of the total size of the
219 * cache and the high water mark is at 110% (both of these percentages can be
220 * changed by setting dbuf_cache_lowater_pct and dbuf_cache_hiwater_pct,
221 * respectively). The eviction thread will try to ensure that the cache remains
222 * within this range by waking up every second and checking if the cache is
223 * above the low water mark. The thread can also be woken up by callers adding
224 * elements into the cache if the cache is larger than the mid water (i.e max
225 * cache size). Once the eviction thread is woken up and eviction is required,
226 * it will continue evicting buffers until it's able to reduce the cache size
227 * to the low water mark. If the cache size continues to grow and hits the high
228 * water mark, then callers adding elements to the cache will begin to evict
229 * directly from the cache until the cache is no longer above the high water
234 * The percentage above and below the maximum cache size.
236 uint_t dbuf_cache_hiwater_pct
= 10;
237 uint_t dbuf_cache_lowater_pct
= 10;
241 dbuf_cons(void *vdb
, void *unused
, int kmflag
)
243 dmu_buf_impl_t
*db
= vdb
;
244 bzero(db
, sizeof (dmu_buf_impl_t
));
246 mutex_init(&db
->db_mtx
, NULL
, MUTEX_DEFAULT
, NULL
);
247 cv_init(&db
->db_changed
, NULL
, CV_DEFAULT
, NULL
);
248 multilist_link_init(&db
->db_cache_link
);
249 refcount_create(&db
->db_holds
);
256 dbuf_dest(void *vdb
, void *unused
)
258 dmu_buf_impl_t
*db
= vdb
;
259 mutex_destroy(&db
->db_mtx
);
260 cv_destroy(&db
->db_changed
);
261 ASSERT(!multilist_link_active(&db
->db_cache_link
));
262 refcount_destroy(&db
->db_holds
);
266 * dbuf hash table routines
268 static dbuf_hash_table_t dbuf_hash_table
;
270 static uint64_t dbuf_hash_count
;
273 dbuf_hash(void *os
, uint64_t obj
, uint8_t lvl
, uint64_t blkid
)
275 uintptr_t osv
= (uintptr_t)os
;
276 uint64_t crc
= -1ULL;
278 ASSERT(zfs_crc64_table
[128] == ZFS_CRC64_POLY
);
279 crc
= (crc
>> 8) ^ zfs_crc64_table
[(crc
^ (lvl
)) & 0xFF];
280 crc
= (crc
>> 8) ^ zfs_crc64_table
[(crc
^ (osv
>> 6)) & 0xFF];
281 crc
= (crc
>> 8) ^ zfs_crc64_table
[(crc
^ (obj
>> 0)) & 0xFF];
282 crc
= (crc
>> 8) ^ zfs_crc64_table
[(crc
^ (obj
>> 8)) & 0xFF];
283 crc
= (crc
>> 8) ^ zfs_crc64_table
[(crc
^ (blkid
>> 0)) & 0xFF];
284 crc
= (crc
>> 8) ^ zfs_crc64_table
[(crc
^ (blkid
>> 8)) & 0xFF];
286 crc
^= (osv
>>14) ^ (obj
>>16) ^ (blkid
>>16);
291 #define DBUF_EQUAL(dbuf, os, obj, level, blkid) \
292 ((dbuf)->db.db_object == (obj) && \
293 (dbuf)->db_objset == (os) && \
294 (dbuf)->db_level == (level) && \
295 (dbuf)->db_blkid == (blkid))
298 dbuf_find(objset_t
*os
, uint64_t obj
, uint8_t level
, uint64_t blkid
)
300 dbuf_hash_table_t
*h
= &dbuf_hash_table
;
305 hv
= dbuf_hash(os
, obj
, level
, blkid
);
306 idx
= hv
& h
->hash_table_mask
;
308 mutex_enter(DBUF_HASH_MUTEX(h
, idx
));
309 for (db
= h
->hash_table
[idx
]; db
!= NULL
; db
= db
->db_hash_next
) {
310 if (DBUF_EQUAL(db
, os
, obj
, level
, blkid
)) {
311 mutex_enter(&db
->db_mtx
);
312 if (db
->db_state
!= DB_EVICTING
) {
313 mutex_exit(DBUF_HASH_MUTEX(h
, idx
));
316 mutex_exit(&db
->db_mtx
);
319 mutex_exit(DBUF_HASH_MUTEX(h
, idx
));
323 static dmu_buf_impl_t
*
324 dbuf_find_bonus(objset_t
*os
, uint64_t object
)
327 dmu_buf_impl_t
*db
= NULL
;
329 if (dnode_hold(os
, object
, FTAG
, &dn
) == 0) {
330 rw_enter(&dn
->dn_struct_rwlock
, RW_READER
);
331 if (dn
->dn_bonus
!= NULL
) {
333 mutex_enter(&db
->db_mtx
);
335 rw_exit(&dn
->dn_struct_rwlock
);
336 dnode_rele(dn
, FTAG
);
342 * Insert an entry into the hash table. If there is already an element
343 * equal to elem in the hash table, then the already existing element
344 * will be returned and the new element will not be inserted.
345 * Otherwise returns NULL.
347 static dmu_buf_impl_t
*
348 dbuf_hash_insert(dmu_buf_impl_t
*db
)
350 dbuf_hash_table_t
*h
= &dbuf_hash_table
;
351 objset_t
*os
= db
->db_objset
;
352 uint64_t obj
= db
->db
.db_object
;
353 int level
= db
->db_level
;
354 uint64_t blkid
, hv
, idx
;
358 blkid
= db
->db_blkid
;
359 hv
= dbuf_hash(os
, obj
, level
, blkid
);
360 idx
= hv
& h
->hash_table_mask
;
362 mutex_enter(DBUF_HASH_MUTEX(h
, idx
));
363 for (dbf
= h
->hash_table
[idx
], i
= 0; dbf
!= NULL
;
364 dbf
= dbf
->db_hash_next
, i
++) {
365 if (DBUF_EQUAL(dbf
, os
, obj
, level
, blkid
)) {
366 mutex_enter(&dbf
->db_mtx
);
367 if (dbf
->db_state
!= DB_EVICTING
) {
368 mutex_exit(DBUF_HASH_MUTEX(h
, idx
));
371 mutex_exit(&dbf
->db_mtx
);
376 DBUF_STAT_BUMP(hash_collisions
);
378 DBUF_STAT_BUMP(hash_chains
);
380 DBUF_STAT_MAX(hash_chain_max
, i
);
383 mutex_enter(&db
->db_mtx
);
384 db
->db_hash_next
= h
->hash_table
[idx
];
385 h
->hash_table
[idx
] = db
;
386 mutex_exit(DBUF_HASH_MUTEX(h
, idx
));
387 atomic_inc_64(&dbuf_hash_count
);
388 DBUF_STAT_MAX(hash_elements_max
, dbuf_hash_count
);
394 * Remove an entry from the hash table. It must be in the EVICTING state.
397 dbuf_hash_remove(dmu_buf_impl_t
*db
)
399 dbuf_hash_table_t
*h
= &dbuf_hash_table
;
401 dmu_buf_impl_t
*dbf
, **dbp
;
403 hv
= dbuf_hash(db
->db_objset
, db
->db
.db_object
,
404 db
->db_level
, db
->db_blkid
);
405 idx
= hv
& h
->hash_table_mask
;
408 * We mustn't hold db_mtx to maintain lock ordering:
409 * DBUF_HASH_MUTEX > db_mtx.
411 ASSERT(refcount_is_zero(&db
->db_holds
));
412 ASSERT(db
->db_state
== DB_EVICTING
);
413 ASSERT(!MUTEX_HELD(&db
->db_mtx
));
415 mutex_enter(DBUF_HASH_MUTEX(h
, idx
));
416 dbp
= &h
->hash_table
[idx
];
417 while ((dbf
= *dbp
) != db
) {
418 dbp
= &dbf
->db_hash_next
;
421 *dbp
= db
->db_hash_next
;
422 db
->db_hash_next
= NULL
;
423 if (h
->hash_table
[idx
] &&
424 h
->hash_table
[idx
]->db_hash_next
== NULL
)
425 DBUF_STAT_BUMPDOWN(hash_chains
);
426 mutex_exit(DBUF_HASH_MUTEX(h
, idx
));
427 atomic_dec_64(&dbuf_hash_count
);
433 } dbvu_verify_type_t
;
436 dbuf_verify_user(dmu_buf_impl_t
*db
, dbvu_verify_type_t verify_type
)
441 if (db
->db_user
== NULL
)
444 /* Only data blocks support the attachment of user data. */
445 ASSERT(db
->db_level
== 0);
447 /* Clients must resolve a dbuf before attaching user data. */
448 ASSERT(db
->db
.db_data
!= NULL
);
449 ASSERT3U(db
->db_state
, ==, DB_CACHED
);
451 holds
= refcount_count(&db
->db_holds
);
452 if (verify_type
== DBVU_EVICTING
) {
454 * Immediate eviction occurs when holds == dirtycnt.
455 * For normal eviction buffers, holds is zero on
456 * eviction, except when dbuf_fix_old_data() calls
457 * dbuf_clear_data(). However, the hold count can grow
458 * during eviction even though db_mtx is held (see
459 * dmu_bonus_hold() for an example), so we can only
460 * test the generic invariant that holds >= dirtycnt.
462 ASSERT3U(holds
, >=, db
->db_dirtycnt
);
464 if (db
->db_user_immediate_evict
== TRUE
)
465 ASSERT3U(holds
, >=, db
->db_dirtycnt
);
467 ASSERT3U(holds
, >, 0);
473 dbuf_evict_user(dmu_buf_impl_t
*db
)
475 dmu_buf_user_t
*dbu
= db
->db_user
;
477 ASSERT(MUTEX_HELD(&db
->db_mtx
));
482 dbuf_verify_user(db
, DBVU_EVICTING
);
486 if (dbu
->dbu_clear_on_evict_dbufp
!= NULL
)
487 *dbu
->dbu_clear_on_evict_dbufp
= NULL
;
491 * There are two eviction callbacks - one that we call synchronously
492 * and one that we invoke via a taskq. The async one is useful for
493 * avoiding lock order reversals and limiting stack depth.
495 * Note that if we have a sync callback but no async callback,
496 * it's likely that the sync callback will free the structure
497 * containing the dbu. In that case we need to take care to not
498 * dereference dbu after calling the sync evict func.
500 boolean_t has_async
= (dbu
->dbu_evict_func_async
!= NULL
);
502 if (dbu
->dbu_evict_func_sync
!= NULL
)
503 dbu
->dbu_evict_func_sync(dbu
);
506 taskq_dispatch_ent(dbu_evict_taskq
, dbu
->dbu_evict_func_async
,
507 dbu
, 0, &dbu
->dbu_tqent
);
512 dbuf_is_metadata(dmu_buf_impl_t
*db
)
515 * Consider indirect blocks and spill blocks to be meta data.
517 if (db
->db_level
> 0 || db
->db_blkid
== DMU_SPILL_BLKID
) {
520 boolean_t is_metadata
;
523 is_metadata
= DMU_OT_IS_METADATA(DB_DNODE(db
)->dn_type
);
526 return (is_metadata
);
532 * This function *must* return indices evenly distributed between all
533 * sublists of the multilist. This is needed due to how the dbuf eviction
534 * code is laid out; dbuf_evict_thread() assumes dbufs are evenly
535 * distributed between all sublists and uses this assumption when
536 * deciding which sublist to evict from and how much to evict from it.
539 dbuf_cache_multilist_index_func(multilist_t
*ml
, void *obj
)
541 dmu_buf_impl_t
*db
= obj
;
544 * The assumption here, is the hash value for a given
545 * dmu_buf_impl_t will remain constant throughout it's lifetime
546 * (i.e. it's objset, object, level and blkid fields don't change).
547 * Thus, we don't need to store the dbuf's sublist index
548 * on insertion, as this index can be recalculated on removal.
550 * Also, the low order bits of the hash value are thought to be
551 * distributed evenly. Otherwise, in the case that the multilist
552 * has a power of two number of sublists, each sublists' usage
553 * would not be evenly distributed.
555 return (dbuf_hash(db
->db_objset
, db
->db
.db_object
,
556 db
->db_level
, db
->db_blkid
) %
557 multilist_get_num_sublists(ml
));
560 static inline unsigned long
561 dbuf_cache_target_bytes(void)
563 return MIN(dbuf_cache_max_bytes
,
564 arc_target_bytes() >> dbuf_cache_max_shift
);
567 static inline uint64_t
568 dbuf_cache_hiwater_bytes(void)
570 uint64_t dbuf_cache_target
= dbuf_cache_target_bytes();
571 return (dbuf_cache_target
+
572 (dbuf_cache_target
* dbuf_cache_hiwater_pct
) / 100);
575 static inline uint64_t
576 dbuf_cache_lowater_bytes(void)
578 uint64_t dbuf_cache_target
= dbuf_cache_target_bytes();
579 return (dbuf_cache_target
-
580 (dbuf_cache_target
* dbuf_cache_lowater_pct
) / 100);
583 static inline boolean_t
584 dbuf_cache_above_hiwater(void)
586 return (refcount_count(&dbuf_cache_size
) > dbuf_cache_hiwater_bytes());
589 static inline boolean_t
590 dbuf_cache_above_lowater(void)
592 return (refcount_count(&dbuf_cache_size
) > dbuf_cache_lowater_bytes());
596 * Evict the oldest eligible dbuf from the dbuf cache.
601 int idx
= multilist_get_random_index(dbuf_cache
);
602 multilist_sublist_t
*mls
= multilist_sublist_lock(dbuf_cache
, idx
);
604 ASSERT(!MUTEX_HELD(&dbuf_evict_lock
));
607 * Set the thread's tsd to indicate that it's processing evictions.
608 * Once a thread stops evicting from the dbuf cache it will
609 * reset its tsd to NULL.
611 ASSERT3P(tsd_get(zfs_dbuf_evict_key
), ==, NULL
);
612 (void) tsd_set(zfs_dbuf_evict_key
, (void *)B_TRUE
);
614 dmu_buf_impl_t
*db
= multilist_sublist_tail(mls
);
615 while (db
!= NULL
&& mutex_tryenter(&db
->db_mtx
) == 0) {
616 db
= multilist_sublist_prev(mls
, db
);
619 DTRACE_PROBE2(dbuf__evict__one
, dmu_buf_impl_t
*, db
,
620 multilist_sublist_t
*, mls
);
623 multilist_sublist_remove(mls
, db
);
624 multilist_sublist_unlock(mls
);
625 (void) refcount_remove_many(&dbuf_cache_size
,
627 DBUF_STAT_BUMPDOWN(cache_levels
[db
->db_level
]);
628 DBUF_STAT_BUMPDOWN(cache_count
);
629 DBUF_STAT_DECR(cache_levels_bytes
[db
->db_level
],
632 DBUF_STAT_MAX(cache_size_bytes_max
,
633 refcount_count(&dbuf_cache_size
));
634 DBUF_STAT_BUMP(cache_total_evicts
);
636 multilist_sublist_unlock(mls
);
638 (void) tsd_set(zfs_dbuf_evict_key
, NULL
);
642 * The dbuf evict thread is responsible for aging out dbufs from the
643 * cache. Once the cache has reached it's maximum size, dbufs are removed
644 * and destroyed. The eviction thread will continue running until the size
645 * of the dbuf cache is at or below the maximum size. Once the dbuf is aged
646 * out of the cache it is destroyed and becomes eligible for arc eviction.
650 dbuf_evict_thread(void *unused
)
654 CALLB_CPR_INIT(&cpr
, &dbuf_evict_lock
, callb_generic_cpr
, FTAG
);
656 mutex_enter(&dbuf_evict_lock
);
657 while (!dbuf_evict_thread_exit
) {
658 while (!dbuf_cache_above_lowater() && !dbuf_evict_thread_exit
) {
659 CALLB_CPR_SAFE_BEGIN(&cpr
);
660 (void) cv_timedwait_sig_hires(&dbuf_evict_cv
,
661 &dbuf_evict_lock
, SEC2NSEC(1), MSEC2NSEC(1), 0);
662 CALLB_CPR_SAFE_END(&cpr
, &dbuf_evict_lock
);
664 mutex_exit(&dbuf_evict_lock
);
667 * Keep evicting as long as we're above the low water mark
668 * for the cache. We do this without holding the locks to
669 * minimize lock contention.
671 while (dbuf_cache_above_lowater() && !dbuf_evict_thread_exit
) {
675 mutex_enter(&dbuf_evict_lock
);
678 dbuf_evict_thread_exit
= B_FALSE
;
679 cv_broadcast(&dbuf_evict_cv
);
680 CALLB_CPR_EXIT(&cpr
); /* drops dbuf_evict_lock */
685 * Wake up the dbuf eviction thread if the dbuf cache is at its max size.
686 * If the dbuf cache is at its high water mark, then evict a dbuf from the
687 * dbuf cache using the callers context.
690 dbuf_evict_notify(void)
694 * We use thread specific data to track when a thread has
695 * started processing evictions. This allows us to avoid deeply
696 * nested stacks that would have a call flow similar to this:
698 * dbuf_rele()-->dbuf_rele_and_unlock()-->dbuf_evict_notify()
701 * +-----dbuf_destroy()<--dbuf_evict_one()<--------+
703 * The dbuf_eviction_thread will always have its tsd set until
704 * that thread exits. All other threads will only set their tsd
705 * if they are participating in the eviction process. This only
706 * happens if the eviction thread is unable to process evictions
707 * fast enough. To keep the dbuf cache size in check, other threads
708 * can evict from the dbuf cache directly. Those threads will set
709 * their tsd values so that we ensure that they only evict one dbuf
710 * from the dbuf cache.
712 if (tsd_get(zfs_dbuf_evict_key
) != NULL
)
716 * We check if we should evict without holding the dbuf_evict_lock,
717 * because it's OK to occasionally make the wrong decision here,
718 * and grabbing the lock results in massive lock contention.
720 if (refcount_count(&dbuf_cache_size
) > dbuf_cache_target_bytes()) {
721 if (dbuf_cache_above_hiwater())
723 cv_signal(&dbuf_evict_cv
);
728 dbuf_kstat_update(kstat_t
*ksp
, int rw
)
730 dbuf_stats_t
*ds
= ksp
->ks_data
;
732 if (rw
== KSTAT_WRITE
) {
733 return (SET_ERROR(EACCES
));
735 ds
->cache_size_bytes
.value
.ui64
=
736 refcount_count(&dbuf_cache_size
);
737 ds
->cache_target_bytes
.value
.ui64
= dbuf_cache_target_bytes();
738 ds
->cache_hiwater_bytes
.value
.ui64
= dbuf_cache_hiwater_bytes();
739 ds
->cache_lowater_bytes
.value
.ui64
= dbuf_cache_lowater_bytes();
740 ds
->hash_elements
.value
.ui64
= dbuf_hash_count
;
749 uint64_t hsize
= 1ULL << 16;
750 dbuf_hash_table_t
*h
= &dbuf_hash_table
;
754 * The hash table is big enough to fill all of physical memory
755 * with an average block size of zfs_arc_average_blocksize (default 8K).
756 * By default, the table will take up
757 * totalmem * sizeof(void*) / 8K (1MB per GB with 8-byte pointers).
759 while (hsize
* zfs_arc_average_blocksize
< physmem
* PAGESIZE
)
763 h
->hash_table_mask
= hsize
- 1;
764 #if defined(_KERNEL) && defined(HAVE_SPL)
766 * Large allocations which do not require contiguous pages
767 * should be using vmem_alloc() in the linux kernel
769 h
->hash_table
= vmem_zalloc(hsize
* sizeof (void *), KM_SLEEP
);
771 h
->hash_table
= kmem_zalloc(hsize
* sizeof (void *), KM_NOSLEEP
);
773 if (h
->hash_table
== NULL
) {
774 /* XXX - we should really return an error instead of assert */
775 ASSERT(hsize
> (1ULL << 10));
780 dbuf_kmem_cache
= kmem_cache_create("dmu_buf_impl_t",
781 sizeof (dmu_buf_impl_t
),
782 0, dbuf_cons
, dbuf_dest
, NULL
, NULL
, NULL
, 0);
784 for (i
= 0; i
< DBUF_MUTEXES
; i
++)
785 mutex_init(&h
->hash_mutexes
[i
], NULL
, MUTEX_DEFAULT
, NULL
);
790 * Setup the parameters for the dbuf cache. We cap the size of the
791 * dbuf cache to 1/32nd (default) of the size of the ARC.
793 dbuf_cache_max_bytes
= MIN(dbuf_cache_max_bytes
,
794 arc_target_bytes() >> dbuf_cache_max_shift
);
797 * All entries are queued via taskq_dispatch_ent(), so min/maxalloc
798 * configuration is not required.
800 dbu_evict_taskq
= taskq_create("dbu_evict", 1, defclsyspri
, 0, 0, 0);
802 dbuf_cache
= multilist_create(sizeof (dmu_buf_impl_t
),
803 offsetof(dmu_buf_impl_t
, db_cache_link
),
804 dbuf_cache_multilist_index_func
);
805 refcount_create(&dbuf_cache_size
);
807 tsd_create(&zfs_dbuf_evict_key
, NULL
);
808 dbuf_evict_thread_exit
= B_FALSE
;
809 mutex_init(&dbuf_evict_lock
, NULL
, MUTEX_DEFAULT
, NULL
);
810 cv_init(&dbuf_evict_cv
, NULL
, CV_DEFAULT
, NULL
);
811 dbuf_cache_evict_thread
= thread_create(NULL
, 0, dbuf_evict_thread
,
812 NULL
, 0, &p0
, TS_RUN
, minclsyspri
);
814 dbuf_ksp
= kstat_create("zfs", 0, "dbufstats", "misc",
815 KSTAT_TYPE_NAMED
, sizeof (dbuf_stats
) / sizeof (kstat_named_t
),
817 if (dbuf_ksp
!= NULL
) {
818 dbuf_ksp
->ks_data
= &dbuf_stats
;
819 dbuf_ksp
->ks_update
= dbuf_kstat_update
;
820 kstat_install(dbuf_ksp
);
822 for (i
= 0; i
< DN_MAX_LEVELS
; i
++) {
823 snprintf(dbuf_stats
.cache_levels
[i
].name
,
824 KSTAT_STRLEN
, "cache_level_%d", i
);
825 dbuf_stats
.cache_levels
[i
].data_type
=
827 snprintf(dbuf_stats
.cache_levels_bytes
[i
].name
,
828 KSTAT_STRLEN
, "cache_level_%d_bytes", i
);
829 dbuf_stats
.cache_levels_bytes
[i
].data_type
=
838 dbuf_hash_table_t
*h
= &dbuf_hash_table
;
841 dbuf_stats_destroy();
843 for (i
= 0; i
< DBUF_MUTEXES
; i
++)
844 mutex_destroy(&h
->hash_mutexes
[i
]);
845 #if defined(_KERNEL) && defined(HAVE_SPL)
847 * Large allocations which do not require contiguous pages
848 * should be using vmem_free() in the linux kernel
850 vmem_free(h
->hash_table
, (h
->hash_table_mask
+ 1) * sizeof (void *));
852 kmem_free(h
->hash_table
, (h
->hash_table_mask
+ 1) * sizeof (void *));
854 kmem_cache_destroy(dbuf_kmem_cache
);
855 taskq_destroy(dbu_evict_taskq
);
857 mutex_enter(&dbuf_evict_lock
);
858 dbuf_evict_thread_exit
= B_TRUE
;
859 while (dbuf_evict_thread_exit
) {
860 cv_signal(&dbuf_evict_cv
);
861 cv_wait(&dbuf_evict_cv
, &dbuf_evict_lock
);
863 mutex_exit(&dbuf_evict_lock
);
864 tsd_destroy(&zfs_dbuf_evict_key
);
866 mutex_destroy(&dbuf_evict_lock
);
867 cv_destroy(&dbuf_evict_cv
);
869 refcount_destroy(&dbuf_cache_size
);
870 multilist_destroy(dbuf_cache
);
872 if (dbuf_ksp
!= NULL
) {
873 kstat_delete(dbuf_ksp
);
884 dbuf_verify(dmu_buf_impl_t
*db
)
887 dbuf_dirty_record_t
*dr
;
889 ASSERT(MUTEX_HELD(&db
->db_mtx
));
891 if (!(zfs_flags
& ZFS_DEBUG_DBUF_VERIFY
))
894 ASSERT(db
->db_objset
!= NULL
);
898 ASSERT(db
->db_parent
== NULL
);
899 ASSERT(db
->db_blkptr
== NULL
);
901 ASSERT3U(db
->db
.db_object
, ==, dn
->dn_object
);
902 ASSERT3P(db
->db_objset
, ==, dn
->dn_objset
);
903 ASSERT3U(db
->db_level
, <, dn
->dn_nlevels
);
904 ASSERT(db
->db_blkid
== DMU_BONUS_BLKID
||
905 db
->db_blkid
== DMU_SPILL_BLKID
||
906 !avl_is_empty(&dn
->dn_dbufs
));
908 if (db
->db_blkid
== DMU_BONUS_BLKID
) {
910 ASSERT3U(db
->db
.db_size
, >=, dn
->dn_bonuslen
);
911 ASSERT3U(db
->db
.db_offset
, ==, DMU_BONUS_BLKID
);
912 } else if (db
->db_blkid
== DMU_SPILL_BLKID
) {
914 ASSERT0(db
->db
.db_offset
);
916 ASSERT3U(db
->db
.db_offset
, ==, db
->db_blkid
* db
->db
.db_size
);
919 for (dr
= db
->db_data_pending
; dr
!= NULL
; dr
= dr
->dr_next
)
920 ASSERT(dr
->dr_dbuf
== db
);
922 for (dr
= db
->db_last_dirty
; dr
!= NULL
; dr
= dr
->dr_next
)
923 ASSERT(dr
->dr_dbuf
== db
);
926 * We can't assert that db_size matches dn_datablksz because it
927 * can be momentarily different when another thread is doing
930 if (db
->db_level
== 0 && db
->db
.db_object
== DMU_META_DNODE_OBJECT
) {
931 dr
= db
->db_data_pending
;
933 * It should only be modified in syncing context, so
934 * make sure we only have one copy of the data.
936 ASSERT(dr
== NULL
|| dr
->dt
.dl
.dr_data
== db
->db_buf
);
939 /* verify db->db_blkptr */
941 if (db
->db_parent
== dn
->dn_dbuf
) {
942 /* db is pointed to by the dnode */
943 /* ASSERT3U(db->db_blkid, <, dn->dn_nblkptr); */
944 if (DMU_OBJECT_IS_SPECIAL(db
->db
.db_object
))
945 ASSERT(db
->db_parent
== NULL
);
947 ASSERT(db
->db_parent
!= NULL
);
948 if (db
->db_blkid
!= DMU_SPILL_BLKID
)
949 ASSERT3P(db
->db_blkptr
, ==,
950 &dn
->dn_phys
->dn_blkptr
[db
->db_blkid
]);
952 /* db is pointed to by an indirect block */
953 ASSERTV(int epb
= db
->db_parent
->db
.db_size
>>
955 ASSERT3U(db
->db_parent
->db_level
, ==, db
->db_level
+1);
956 ASSERT3U(db
->db_parent
->db
.db_object
, ==,
959 * dnode_grow_indblksz() can make this fail if we don't
960 * have the struct_rwlock. XXX indblksz no longer
961 * grows. safe to do this now?
963 if (RW_WRITE_HELD(&dn
->dn_struct_rwlock
)) {
964 ASSERT3P(db
->db_blkptr
, ==,
965 ((blkptr_t
*)db
->db_parent
->db
.db_data
+
966 db
->db_blkid
% epb
));
970 if ((db
->db_blkptr
== NULL
|| BP_IS_HOLE(db
->db_blkptr
)) &&
971 (db
->db_buf
== NULL
|| db
->db_buf
->b_data
) &&
972 db
->db
.db_data
&& db
->db_blkid
!= DMU_BONUS_BLKID
&&
973 db
->db_state
!= DB_FILL
&& !dn
->dn_free_txg
) {
975 * If the blkptr isn't set but they have nonzero data,
976 * it had better be dirty, otherwise we'll lose that
977 * data when we evict this buffer.
979 * There is an exception to this rule for indirect blocks; in
980 * this case, if the indirect block is a hole, we fill in a few
981 * fields on each of the child blocks (importantly, birth time)
982 * to prevent hole birth times from being lost when you
983 * partially fill in a hole.
985 if (db
->db_dirtycnt
== 0) {
986 if (db
->db_level
== 0) {
987 uint64_t *buf
= db
->db
.db_data
;
990 for (i
= 0; i
< db
->db
.db_size
>> 3; i
++) {
994 blkptr_t
*bps
= db
->db
.db_data
;
995 ASSERT3U(1 << DB_DNODE(db
)->dn_indblkshift
, ==,
998 * We want to verify that all the blkptrs in the
999 * indirect block are holes, but we may have
1000 * automatically set up a few fields for them.
1001 * We iterate through each blkptr and verify
1002 * they only have those fields set.
1005 i
< db
->db
.db_size
/ sizeof (blkptr_t
);
1007 blkptr_t
*bp
= &bps
[i
];
1008 ASSERT(ZIO_CHECKSUM_IS_ZERO(
1011 DVA_IS_EMPTY(&bp
->blk_dva
[0]) &&
1012 DVA_IS_EMPTY(&bp
->blk_dva
[1]) &&
1013 DVA_IS_EMPTY(&bp
->blk_dva
[2]));
1014 ASSERT0(bp
->blk_fill
);
1015 ASSERT0(bp
->blk_pad
[0]);
1016 ASSERT0(bp
->blk_pad
[1]);
1017 ASSERT(!BP_IS_EMBEDDED(bp
));
1018 ASSERT(BP_IS_HOLE(bp
));
1019 ASSERT0(bp
->blk_phys_birth
);
1029 dbuf_clear_data(dmu_buf_impl_t
*db
)
1031 ASSERT(MUTEX_HELD(&db
->db_mtx
));
1032 dbuf_evict_user(db
);
1033 ASSERT3P(db
->db_buf
, ==, NULL
);
1034 db
->db
.db_data
= NULL
;
1035 if (db
->db_state
!= DB_NOFILL
)
1036 db
->db_state
= DB_UNCACHED
;
1040 dbuf_set_data(dmu_buf_impl_t
*db
, arc_buf_t
*buf
)
1042 ASSERT(MUTEX_HELD(&db
->db_mtx
));
1043 ASSERT(buf
!= NULL
);
1046 ASSERT(buf
->b_data
!= NULL
);
1047 db
->db
.db_data
= buf
->b_data
;
1051 * Loan out an arc_buf for read. Return the loaned arc_buf.
1054 dbuf_loan_arcbuf(dmu_buf_impl_t
*db
)
1058 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
1059 mutex_enter(&db
->db_mtx
);
1060 if (arc_released(db
->db_buf
) || refcount_count(&db
->db_holds
) > 1) {
1061 int blksz
= db
->db
.db_size
;
1062 spa_t
*spa
= db
->db_objset
->os_spa
;
1064 mutex_exit(&db
->db_mtx
);
1065 abuf
= arc_loan_buf(spa
, B_FALSE
, blksz
);
1066 bcopy(db
->db
.db_data
, abuf
->b_data
, blksz
);
1069 arc_loan_inuse_buf(abuf
, db
);
1071 dbuf_clear_data(db
);
1072 mutex_exit(&db
->db_mtx
);
1078 * Calculate which level n block references the data at the level 0 offset
1082 dbuf_whichblock(const dnode_t
*dn
, const int64_t level
, const uint64_t offset
)
1084 if (dn
->dn_datablkshift
!= 0 && dn
->dn_indblkshift
!= 0) {
1086 * The level n blkid is equal to the level 0 blkid divided by
1087 * the number of level 0s in a level n block.
1089 * The level 0 blkid is offset >> datablkshift =
1090 * offset / 2^datablkshift.
1092 * The number of level 0s in a level n is the number of block
1093 * pointers in an indirect block, raised to the power of level.
1094 * This is 2^(indblkshift - SPA_BLKPTRSHIFT)^level =
1095 * 2^(level*(indblkshift - SPA_BLKPTRSHIFT)).
1097 * Thus, the level n blkid is: offset /
1098 * ((2^datablkshift)*(2^(level*(indblkshift - SPA_BLKPTRSHIFT)))
1099 * = offset / 2^(datablkshift + level *
1100 * (indblkshift - SPA_BLKPTRSHIFT))
1101 * = offset >> (datablkshift + level *
1102 * (indblkshift - SPA_BLKPTRSHIFT))
1105 const unsigned exp
= dn
->dn_datablkshift
+
1106 level
* (dn
->dn_indblkshift
- SPA_BLKPTRSHIFT
);
1108 if (exp
>= 8 * sizeof (offset
)) {
1109 /* This only happens on the highest indirection level */
1110 ASSERT3U(level
, ==, dn
->dn_nlevels
- 1);
1114 ASSERT3U(exp
, <, 8 * sizeof (offset
));
1116 return (offset
>> exp
);
1118 ASSERT3U(offset
, <, dn
->dn_datablksz
);
1124 dbuf_read_done(zio_t
*zio
, const zbookmark_phys_t
*zb
, const blkptr_t
*bp
,
1125 arc_buf_t
*buf
, void *vdb
)
1127 dmu_buf_impl_t
*db
= vdb
;
1129 mutex_enter(&db
->db_mtx
);
1130 ASSERT3U(db
->db_state
, ==, DB_READ
);
1132 * All reads are synchronous, so we must have a hold on the dbuf
1134 ASSERT(refcount_count(&db
->db_holds
) > 0);
1135 ASSERT(db
->db_buf
== NULL
);
1136 ASSERT(db
->db
.db_data
== NULL
);
1137 if (db
->db_level
== 0 && db
->db_freed_in_flight
) {
1138 /* we were freed in flight; disregard any error */
1140 buf
= arc_alloc_buf(db
->db_objset
->os_spa
,
1141 db
, DBUF_GET_BUFC_TYPE(db
), db
->db
.db_size
);
1143 arc_release(buf
, db
);
1144 bzero(buf
->b_data
, db
->db
.db_size
);
1145 arc_buf_freeze(buf
);
1146 db
->db_freed_in_flight
= FALSE
;
1147 dbuf_set_data(db
, buf
);
1148 db
->db_state
= DB_CACHED
;
1149 } else if (buf
!= NULL
) {
1150 dbuf_set_data(db
, buf
);
1151 db
->db_state
= DB_CACHED
;
1153 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
1154 ASSERT3P(db
->db_buf
, ==, NULL
);
1155 db
->db_state
= DB_UNCACHED
;
1157 cv_broadcast(&db
->db_changed
);
1158 dbuf_rele_and_unlock(db
, NULL
);
1162 dbuf_read_impl(dmu_buf_impl_t
*db
, zio_t
*zio
, uint32_t flags
)
1165 zbookmark_phys_t zb
;
1166 uint32_t aflags
= ARC_FLAG_NOWAIT
;
1167 int err
, zio_flags
= 0;
1171 ASSERT(!refcount_is_zero(&db
->db_holds
));
1172 /* We need the struct_rwlock to prevent db_blkptr from changing. */
1173 ASSERT(RW_LOCK_HELD(&dn
->dn_struct_rwlock
));
1174 ASSERT(MUTEX_HELD(&db
->db_mtx
));
1175 ASSERT(db
->db_state
== DB_UNCACHED
);
1176 ASSERT(db
->db_buf
== NULL
);
1178 if (db
->db_blkid
== DMU_BONUS_BLKID
) {
1180 * The bonus length stored in the dnode may be less than
1181 * the maximum available space in the bonus buffer.
1183 int bonuslen
= MIN(dn
->dn_bonuslen
, dn
->dn_phys
->dn_bonuslen
);
1184 int max_bonuslen
= DN_SLOTS_TO_BONUSLEN(dn
->dn_num_slots
);
1185 arc_buf_t
*dn_buf
= (dn
->dn_dbuf
!= NULL
) ?
1186 dn
->dn_dbuf
->db_buf
: NULL
;
1188 /* if the underlying dnode block is encrypted, decrypt it */
1189 if (dn_buf
!= NULL
&& dn
->dn_objset
->os_encrypted
&&
1190 DMU_OT_IS_ENCRYPTED(dn
->dn_bonustype
) &&
1191 (flags
& DB_RF_NO_DECRYPT
) == 0 &&
1192 arc_is_encrypted(dn_buf
)) {
1193 err
= arc_untransform(dn_buf
, dn
->dn_objset
->os_spa
,
1194 dmu_objset_id(dn
->dn_objset
), B_TRUE
);
1197 mutex_exit(&db
->db_mtx
);
1202 ASSERT3U(bonuslen
, <=, db
->db
.db_size
);
1203 db
->db
.db_data
= kmem_alloc(max_bonuslen
, KM_SLEEP
);
1204 arc_space_consume(max_bonuslen
, ARC_SPACE_BONUS
);
1205 if (bonuslen
< max_bonuslen
)
1206 bzero(db
->db
.db_data
, max_bonuslen
);
1208 bcopy(DN_BONUS(dn
->dn_phys
), db
->db
.db_data
, bonuslen
);
1210 db
->db_state
= DB_CACHED
;
1211 mutex_exit(&db
->db_mtx
);
1216 * Recheck BP_IS_HOLE() after dnode_block_freed() in case dnode_sync()
1217 * processes the delete record and clears the bp while we are waiting
1218 * for the dn_mtx (resulting in a "no" from block_freed).
1220 if (db
->db_blkptr
== NULL
|| BP_IS_HOLE(db
->db_blkptr
) ||
1221 (db
->db_level
== 0 && (dnode_block_freed(dn
, db
->db_blkid
) ||
1222 BP_IS_HOLE(db
->db_blkptr
)))) {
1223 arc_buf_contents_t type
= DBUF_GET_BUFC_TYPE(db
);
1225 dbuf_set_data(db
, arc_alloc_buf(db
->db_objset
->os_spa
, db
, type
,
1227 bzero(db
->db
.db_data
, db
->db
.db_size
);
1229 if (db
->db_blkptr
!= NULL
&& db
->db_level
> 0 &&
1230 BP_IS_HOLE(db
->db_blkptr
) &&
1231 db
->db_blkptr
->blk_birth
!= 0) {
1232 blkptr_t
*bps
= db
->db
.db_data
;
1233 for (int i
= 0; i
< ((1 <<
1234 DB_DNODE(db
)->dn_indblkshift
) / sizeof (blkptr_t
));
1236 blkptr_t
*bp
= &bps
[i
];
1237 ASSERT3U(BP_GET_LSIZE(db
->db_blkptr
), ==,
1238 1 << dn
->dn_indblkshift
);
1240 BP_GET_LEVEL(db
->db_blkptr
) == 1 ?
1242 BP_GET_LSIZE(db
->db_blkptr
));
1243 BP_SET_TYPE(bp
, BP_GET_TYPE(db
->db_blkptr
));
1245 BP_GET_LEVEL(db
->db_blkptr
) - 1);
1246 BP_SET_BIRTH(bp
, db
->db_blkptr
->blk_birth
, 0);
1250 db
->db_state
= DB_CACHED
;
1251 mutex_exit(&db
->db_mtx
);
1257 db
->db_state
= DB_READ
;
1258 mutex_exit(&db
->db_mtx
);
1260 if (DBUF_IS_L2CACHEABLE(db
))
1261 aflags
|= ARC_FLAG_L2CACHE
;
1263 SET_BOOKMARK(&zb
, db
->db_objset
->os_dsl_dataset
?
1264 db
->db_objset
->os_dsl_dataset
->ds_object
: DMU_META_OBJSET
,
1265 db
->db
.db_object
, db
->db_level
, db
->db_blkid
);
1268 * All bps of an encrypted os should have the encryption bit set.
1269 * If this is not true it indicates tampering and we report an error.
1271 if (db
->db_objset
->os_encrypted
&& !BP_USES_CRYPT(db
->db_blkptr
)) {
1272 spa_log_error(db
->db_objset
->os_spa
, &zb
);
1273 zfs_panic_recover("unencrypted block in encrypted "
1274 "object set %llu", dmu_objset_id(db
->db_objset
));
1275 return (SET_ERROR(EIO
));
1278 dbuf_add_ref(db
, NULL
);
1280 zio_flags
= (flags
& DB_RF_CANFAIL
) ?
1281 ZIO_FLAG_CANFAIL
: ZIO_FLAG_MUSTSUCCEED
;
1283 if ((flags
& DB_RF_NO_DECRYPT
) && BP_IS_PROTECTED(db
->db_blkptr
))
1284 zio_flags
|= ZIO_FLAG_RAW
;
1286 err
= arc_read(zio
, db
->db_objset
->os_spa
, db
->db_blkptr
,
1287 dbuf_read_done
, db
, ZIO_PRIORITY_SYNC_READ
, zio_flags
,
1294 * This is our just-in-time copy function. It makes a copy of buffers that
1295 * have been modified in a previous transaction group before we access them in
1296 * the current active group.
1298 * This function is used in three places: when we are dirtying a buffer for the
1299 * first time in a txg, when we are freeing a range in a dnode that includes
1300 * this buffer, and when we are accessing a buffer which was received compressed
1301 * and later referenced in a WRITE_BYREF record.
1303 * Note that when we are called from dbuf_free_range() we do not put a hold on
1304 * the buffer, we just traverse the active dbuf list for the dnode.
1307 dbuf_fix_old_data(dmu_buf_impl_t
*db
, uint64_t txg
)
1309 dbuf_dirty_record_t
*dr
= db
->db_last_dirty
;
1311 ASSERT(MUTEX_HELD(&db
->db_mtx
));
1312 ASSERT(db
->db
.db_data
!= NULL
);
1313 ASSERT(db
->db_level
== 0);
1314 ASSERT(db
->db
.db_object
!= DMU_META_DNODE_OBJECT
);
1317 (dr
->dt
.dl
.dr_data
!=
1318 ((db
->db_blkid
== DMU_BONUS_BLKID
) ? db
->db
.db_data
: db
->db_buf
)))
1322 * If the last dirty record for this dbuf has not yet synced
1323 * and its referencing the dbuf data, either:
1324 * reset the reference to point to a new copy,
1325 * or (if there a no active holders)
1326 * just null out the current db_data pointer.
1328 ASSERT3U(dr
->dr_txg
, >=, txg
- 2);
1329 if (db
->db_blkid
== DMU_BONUS_BLKID
) {
1330 dnode_t
*dn
= DB_DNODE(db
);
1331 int bonuslen
= DN_SLOTS_TO_BONUSLEN(dn
->dn_num_slots
);
1332 dr
->dt
.dl
.dr_data
= kmem_alloc(bonuslen
, KM_SLEEP
);
1333 arc_space_consume(bonuslen
, ARC_SPACE_BONUS
);
1334 bcopy(db
->db
.db_data
, dr
->dt
.dl
.dr_data
, bonuslen
);
1335 } else if (refcount_count(&db
->db_holds
) > db
->db_dirtycnt
) {
1336 dnode_t
*dn
= DB_DNODE(db
);
1337 int size
= arc_buf_size(db
->db_buf
);
1338 arc_buf_contents_t type
= DBUF_GET_BUFC_TYPE(db
);
1339 spa_t
*spa
= db
->db_objset
->os_spa
;
1340 enum zio_compress compress_type
=
1341 arc_get_compression(db
->db_buf
);
1343 if (arc_is_encrypted(db
->db_buf
)) {
1344 boolean_t byteorder
;
1345 uint8_t salt
[ZIO_DATA_SALT_LEN
];
1346 uint8_t iv
[ZIO_DATA_IV_LEN
];
1347 uint8_t mac
[ZIO_DATA_MAC_LEN
];
1349 arc_get_raw_params(db
->db_buf
, &byteorder
, salt
,
1351 dr
->dt
.dl
.dr_data
= arc_alloc_raw_buf(spa
, db
,
1352 dmu_objset_id(dn
->dn_objset
), byteorder
, salt
, iv
,
1353 mac
, dn
->dn_type
, size
, arc_buf_lsize(db
->db_buf
),
1355 } else if (compress_type
!= ZIO_COMPRESS_OFF
) {
1356 ASSERT3U(type
, ==, ARC_BUFC_DATA
);
1357 dr
->dt
.dl
.dr_data
= arc_alloc_compressed_buf(spa
, db
,
1358 size
, arc_buf_lsize(db
->db_buf
), compress_type
);
1360 dr
->dt
.dl
.dr_data
= arc_alloc_buf(spa
, db
, type
, size
);
1362 bcopy(db
->db
.db_data
, dr
->dt
.dl
.dr_data
->b_data
, size
);
1365 dbuf_clear_data(db
);
1370 dbuf_read(dmu_buf_impl_t
*db
, zio_t
*zio
, uint32_t flags
)
1377 * We don't have to hold the mutex to check db_state because it
1378 * can't be freed while we have a hold on the buffer.
1380 ASSERT(!refcount_is_zero(&db
->db_holds
));
1382 if (db
->db_state
== DB_NOFILL
)
1383 return (SET_ERROR(EIO
));
1387 if ((flags
& DB_RF_HAVESTRUCT
) == 0)
1388 rw_enter(&dn
->dn_struct_rwlock
, RW_READER
);
1390 prefetch
= db
->db_level
== 0 && db
->db_blkid
!= DMU_BONUS_BLKID
&&
1391 (flags
& DB_RF_NOPREFETCH
) == 0 && dn
!= NULL
&&
1392 DBUF_IS_CACHEABLE(db
);
1394 mutex_enter(&db
->db_mtx
);
1395 if (db
->db_state
== DB_CACHED
) {
1396 spa_t
*spa
= dn
->dn_objset
->os_spa
;
1399 * If the arc buf is compressed or encrypted, we need to
1400 * untransform it to read the data. This could happen during
1401 * the "zfs receive" of a stream which is deduplicated and
1402 * either raw or compressed. We do not need to do this if the
1403 * caller wants raw encrypted data.
1405 if (db
->db_buf
!= NULL
&& (flags
& DB_RF_NO_DECRYPT
) == 0 &&
1406 (arc_is_encrypted(db
->db_buf
) ||
1407 arc_get_compression(db
->db_buf
) != ZIO_COMPRESS_OFF
)) {
1408 dbuf_fix_old_data(db
, spa_syncing_txg(spa
));
1409 err
= arc_untransform(db
->db_buf
, spa
,
1410 dmu_objset_id(db
->db_objset
), B_FALSE
);
1411 dbuf_set_data(db
, db
->db_buf
);
1413 mutex_exit(&db
->db_mtx
);
1415 dmu_zfetch(&dn
->dn_zfetch
, db
->db_blkid
, 1, B_TRUE
);
1416 if ((flags
& DB_RF_HAVESTRUCT
) == 0)
1417 rw_exit(&dn
->dn_struct_rwlock
);
1419 DBUF_STAT_BUMP(hash_hits
);
1420 } else if (db
->db_state
== DB_UNCACHED
) {
1421 spa_t
*spa
= dn
->dn_objset
->os_spa
;
1422 boolean_t need_wait
= B_FALSE
;
1425 db
->db_blkptr
!= NULL
&& !BP_IS_HOLE(db
->db_blkptr
)) {
1426 zio
= zio_root(spa
, NULL
, NULL
, ZIO_FLAG_CANFAIL
);
1429 err
= dbuf_read_impl(db
, zio
, flags
);
1431 /* dbuf_read_impl has dropped db_mtx for us */
1433 if (!err
&& prefetch
)
1434 dmu_zfetch(&dn
->dn_zfetch
, db
->db_blkid
, 1, B_TRUE
);
1436 if ((flags
& DB_RF_HAVESTRUCT
) == 0)
1437 rw_exit(&dn
->dn_struct_rwlock
);
1439 DBUF_STAT_BUMP(hash_misses
);
1441 if (!err
&& need_wait
)
1442 err
= zio_wait(zio
);
1445 * Another reader came in while the dbuf was in flight
1446 * between UNCACHED and CACHED. Either a writer will finish
1447 * writing the buffer (sending the dbuf to CACHED) or the
1448 * first reader's request will reach the read_done callback
1449 * and send the dbuf to CACHED. Otherwise, a failure
1450 * occurred and the dbuf went to UNCACHED.
1452 mutex_exit(&db
->db_mtx
);
1454 dmu_zfetch(&dn
->dn_zfetch
, db
->db_blkid
, 1, B_TRUE
);
1455 if ((flags
& DB_RF_HAVESTRUCT
) == 0)
1456 rw_exit(&dn
->dn_struct_rwlock
);
1458 DBUF_STAT_BUMP(hash_misses
);
1460 /* Skip the wait per the caller's request. */
1461 mutex_enter(&db
->db_mtx
);
1462 if ((flags
& DB_RF_NEVERWAIT
) == 0) {
1463 while (db
->db_state
== DB_READ
||
1464 db
->db_state
== DB_FILL
) {
1465 ASSERT(db
->db_state
== DB_READ
||
1466 (flags
& DB_RF_HAVESTRUCT
) == 0);
1467 DTRACE_PROBE2(blocked__read
, dmu_buf_impl_t
*,
1469 cv_wait(&db
->db_changed
, &db
->db_mtx
);
1471 if (db
->db_state
== DB_UNCACHED
)
1472 err
= SET_ERROR(EIO
);
1474 mutex_exit(&db
->db_mtx
);
1481 dbuf_noread(dmu_buf_impl_t
*db
)
1483 ASSERT(!refcount_is_zero(&db
->db_holds
));
1484 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
1485 mutex_enter(&db
->db_mtx
);
1486 while (db
->db_state
== DB_READ
|| db
->db_state
== DB_FILL
)
1487 cv_wait(&db
->db_changed
, &db
->db_mtx
);
1488 if (db
->db_state
== DB_UNCACHED
) {
1489 arc_buf_contents_t type
= DBUF_GET_BUFC_TYPE(db
);
1490 spa_t
*spa
= db
->db_objset
->os_spa
;
1492 ASSERT(db
->db_buf
== NULL
);
1493 ASSERT(db
->db
.db_data
== NULL
);
1494 dbuf_set_data(db
, arc_alloc_buf(spa
, db
, type
, db
->db
.db_size
));
1495 db
->db_state
= DB_FILL
;
1496 } else if (db
->db_state
== DB_NOFILL
) {
1497 dbuf_clear_data(db
);
1499 ASSERT3U(db
->db_state
, ==, DB_CACHED
);
1501 mutex_exit(&db
->db_mtx
);
1505 dbuf_unoverride(dbuf_dirty_record_t
*dr
)
1507 dmu_buf_impl_t
*db
= dr
->dr_dbuf
;
1508 blkptr_t
*bp
= &dr
->dt
.dl
.dr_overridden_by
;
1509 uint64_t txg
= dr
->dr_txg
;
1511 ASSERT(MUTEX_HELD(&db
->db_mtx
));
1513 * This assert is valid because dmu_sync() expects to be called by
1514 * a zilog's get_data while holding a range lock. This call only
1515 * comes from dbuf_dirty() callers who must also hold a range lock.
1517 ASSERT(dr
->dt
.dl
.dr_override_state
!= DR_IN_DMU_SYNC
);
1518 ASSERT(db
->db_level
== 0);
1520 if (db
->db_blkid
== DMU_BONUS_BLKID
||
1521 dr
->dt
.dl
.dr_override_state
== DR_NOT_OVERRIDDEN
)
1524 ASSERT(db
->db_data_pending
!= dr
);
1526 /* free this block */
1527 if (!BP_IS_HOLE(bp
) && !dr
->dt
.dl
.dr_nopwrite
)
1528 zio_free(db
->db_objset
->os_spa
, txg
, bp
);
1530 dr
->dt
.dl
.dr_override_state
= DR_NOT_OVERRIDDEN
;
1531 dr
->dt
.dl
.dr_nopwrite
= B_FALSE
;
1532 dr
->dt
.dl
.dr_raw
= B_FALSE
;
1535 * Release the already-written buffer, so we leave it in
1536 * a consistent dirty state. Note that all callers are
1537 * modifying the buffer, so they will immediately do
1538 * another (redundant) arc_release(). Therefore, leave
1539 * the buf thawed to save the effort of freezing &
1540 * immediately re-thawing it.
1542 arc_release(dr
->dt
.dl
.dr_data
, db
);
1546 * Evict (if its unreferenced) or clear (if its referenced) any level-0
1547 * data blocks in the free range, so that any future readers will find
1551 dbuf_free_range(dnode_t
*dn
, uint64_t start_blkid
, uint64_t end_blkid
,
1554 dmu_buf_impl_t
*db_search
;
1555 dmu_buf_impl_t
*db
, *db_next
;
1556 uint64_t txg
= tx
->tx_txg
;
1559 if (end_blkid
> dn
->dn_maxblkid
&&
1560 !(start_blkid
== DMU_SPILL_BLKID
|| end_blkid
== DMU_SPILL_BLKID
))
1561 end_blkid
= dn
->dn_maxblkid
;
1562 dprintf_dnode(dn
, "start=%llu end=%llu\n", start_blkid
, end_blkid
);
1564 db_search
= kmem_alloc(sizeof (dmu_buf_impl_t
), KM_SLEEP
);
1565 db_search
->db_level
= 0;
1566 db_search
->db_blkid
= start_blkid
;
1567 db_search
->db_state
= DB_SEARCH
;
1569 mutex_enter(&dn
->dn_dbufs_mtx
);
1570 db
= avl_find(&dn
->dn_dbufs
, db_search
, &where
);
1571 ASSERT3P(db
, ==, NULL
);
1573 db
= avl_nearest(&dn
->dn_dbufs
, where
, AVL_AFTER
);
1575 for (; db
!= NULL
; db
= db_next
) {
1576 db_next
= AVL_NEXT(&dn
->dn_dbufs
, db
);
1577 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
1579 if (db
->db_level
!= 0 || db
->db_blkid
> end_blkid
) {
1582 ASSERT3U(db
->db_blkid
, >=, start_blkid
);
1584 /* found a level 0 buffer in the range */
1585 mutex_enter(&db
->db_mtx
);
1586 if (dbuf_undirty(db
, tx
)) {
1587 /* mutex has been dropped and dbuf destroyed */
1591 if (db
->db_state
== DB_UNCACHED
||
1592 db
->db_state
== DB_NOFILL
||
1593 db
->db_state
== DB_EVICTING
) {
1594 ASSERT(db
->db
.db_data
== NULL
);
1595 mutex_exit(&db
->db_mtx
);
1598 if (db
->db_state
== DB_READ
|| db
->db_state
== DB_FILL
) {
1599 /* will be handled in dbuf_read_done or dbuf_rele */
1600 db
->db_freed_in_flight
= TRUE
;
1601 mutex_exit(&db
->db_mtx
);
1604 if (refcount_count(&db
->db_holds
) == 0) {
1609 /* The dbuf is referenced */
1611 if (db
->db_last_dirty
!= NULL
) {
1612 dbuf_dirty_record_t
*dr
= db
->db_last_dirty
;
1614 if (dr
->dr_txg
== txg
) {
1616 * This buffer is "in-use", re-adjust the file
1617 * size to reflect that this buffer may
1618 * contain new data when we sync.
1620 if (db
->db_blkid
!= DMU_SPILL_BLKID
&&
1621 db
->db_blkid
> dn
->dn_maxblkid
)
1622 dn
->dn_maxblkid
= db
->db_blkid
;
1623 dbuf_unoverride(dr
);
1626 * This dbuf is not dirty in the open context.
1627 * Either uncache it (if its not referenced in
1628 * the open context) or reset its contents to
1631 dbuf_fix_old_data(db
, txg
);
1634 /* clear the contents if its cached */
1635 if (db
->db_state
== DB_CACHED
) {
1636 ASSERT(db
->db
.db_data
!= NULL
);
1637 arc_release(db
->db_buf
, db
);
1638 bzero(db
->db
.db_data
, db
->db
.db_size
);
1639 arc_buf_freeze(db
->db_buf
);
1642 mutex_exit(&db
->db_mtx
);
1645 kmem_free(db_search
, sizeof (dmu_buf_impl_t
));
1646 mutex_exit(&dn
->dn_dbufs_mtx
);
1650 dbuf_new_size(dmu_buf_impl_t
*db
, int size
, dmu_tx_t
*tx
)
1652 arc_buf_t
*buf
, *obuf
;
1653 int osize
= db
->db
.db_size
;
1654 arc_buf_contents_t type
= DBUF_GET_BUFC_TYPE(db
);
1657 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
1662 /* XXX does *this* func really need the lock? */
1663 ASSERT(RW_WRITE_HELD(&dn
->dn_struct_rwlock
));
1666 * This call to dmu_buf_will_dirty() with the dn_struct_rwlock held
1667 * is OK, because there can be no other references to the db
1668 * when we are changing its size, so no concurrent DB_FILL can
1672 * XXX we should be doing a dbuf_read, checking the return
1673 * value and returning that up to our callers
1675 dmu_buf_will_dirty(&db
->db
, tx
);
1677 /* create the data buffer for the new block */
1678 buf
= arc_alloc_buf(dn
->dn_objset
->os_spa
, db
, type
, size
);
1680 /* copy old block data to the new block */
1682 bcopy(obuf
->b_data
, buf
->b_data
, MIN(osize
, size
));
1683 /* zero the remainder */
1685 bzero((uint8_t *)buf
->b_data
+ osize
, size
- osize
);
1687 mutex_enter(&db
->db_mtx
);
1688 dbuf_set_data(db
, buf
);
1689 arc_buf_destroy(obuf
, db
);
1690 db
->db
.db_size
= size
;
1692 if (db
->db_level
== 0) {
1693 ASSERT3U(db
->db_last_dirty
->dr_txg
, ==, tx
->tx_txg
);
1694 db
->db_last_dirty
->dt
.dl
.dr_data
= buf
;
1696 mutex_exit(&db
->db_mtx
);
1698 dmu_objset_willuse_space(dn
->dn_objset
, size
- osize
, tx
);
1703 dbuf_release_bp(dmu_buf_impl_t
*db
)
1705 ASSERTV(objset_t
*os
= db
->db_objset
);
1707 ASSERT(dsl_pool_sync_context(dmu_objset_pool(os
)));
1708 ASSERT(arc_released(os
->os_phys_buf
) ||
1709 list_link_active(&os
->os_dsl_dataset
->ds_synced_link
));
1710 ASSERT(db
->db_parent
== NULL
|| arc_released(db
->db_parent
->db_buf
));
1712 (void) arc_release(db
->db_buf
, db
);
1716 * We already have a dirty record for this TXG, and we are being
1720 dbuf_redirty(dbuf_dirty_record_t
*dr
)
1722 dmu_buf_impl_t
*db
= dr
->dr_dbuf
;
1724 ASSERT(MUTEX_HELD(&db
->db_mtx
));
1726 if (db
->db_level
== 0 && db
->db_blkid
!= DMU_BONUS_BLKID
) {
1728 * If this buffer has already been written out,
1729 * we now need to reset its state.
1731 dbuf_unoverride(dr
);
1732 if (db
->db
.db_object
!= DMU_META_DNODE_OBJECT
&&
1733 db
->db_state
!= DB_NOFILL
) {
1734 /* Already released on initial dirty, so just thaw. */
1735 ASSERT(arc_released(db
->db_buf
));
1736 arc_buf_thaw(db
->db_buf
);
1741 dbuf_dirty_record_t
*
1742 dbuf_dirty(dmu_buf_impl_t
*db
, dmu_tx_t
*tx
)
1746 dbuf_dirty_record_t
**drp
, *dr
;
1747 int drop_struct_lock
= FALSE
;
1748 int txgoff
= tx
->tx_txg
& TXG_MASK
;
1750 ASSERT(tx
->tx_txg
!= 0);
1751 ASSERT(!refcount_is_zero(&db
->db_holds
));
1752 DMU_TX_DIRTY_BUF(tx
, db
);
1757 * Shouldn't dirty a regular buffer in syncing context. Private
1758 * objects may be dirtied in syncing context, but only if they
1759 * were already pre-dirtied in open context.
1762 if (dn
->dn_objset
->os_dsl_dataset
!= NULL
) {
1763 rrw_enter(&dn
->dn_objset
->os_dsl_dataset
->ds_bp_rwlock
,
1766 ASSERT(!dmu_tx_is_syncing(tx
) ||
1767 BP_IS_HOLE(dn
->dn_objset
->os_rootbp
) ||
1768 DMU_OBJECT_IS_SPECIAL(dn
->dn_object
) ||
1769 dn
->dn_objset
->os_dsl_dataset
== NULL
);
1770 if (dn
->dn_objset
->os_dsl_dataset
!= NULL
)
1771 rrw_exit(&dn
->dn_objset
->os_dsl_dataset
->ds_bp_rwlock
, FTAG
);
1774 * We make this assert for private objects as well, but after we
1775 * check if we're already dirty. They are allowed to re-dirty
1776 * in syncing context.
1778 ASSERT(dn
->dn_object
== DMU_META_DNODE_OBJECT
||
1779 dn
->dn_dirtyctx
== DN_UNDIRTIED
|| dn
->dn_dirtyctx
==
1780 (dmu_tx_is_syncing(tx
) ? DN_DIRTY_SYNC
: DN_DIRTY_OPEN
));
1782 mutex_enter(&db
->db_mtx
);
1784 * XXX make this true for indirects too? The problem is that
1785 * transactions created with dmu_tx_create_assigned() from
1786 * syncing context don't bother holding ahead.
1788 ASSERT(db
->db_level
!= 0 ||
1789 db
->db_state
== DB_CACHED
|| db
->db_state
== DB_FILL
||
1790 db
->db_state
== DB_NOFILL
);
1792 mutex_enter(&dn
->dn_mtx
);
1794 * Don't set dirtyctx to SYNC if we're just modifying this as we
1795 * initialize the objset.
1797 if (dn
->dn_dirtyctx
== DN_UNDIRTIED
) {
1798 if (dn
->dn_objset
->os_dsl_dataset
!= NULL
) {
1799 rrw_enter(&dn
->dn_objset
->os_dsl_dataset
->ds_bp_rwlock
,
1802 if (!BP_IS_HOLE(dn
->dn_objset
->os_rootbp
)) {
1803 dn
->dn_dirtyctx
= (dmu_tx_is_syncing(tx
) ?
1804 DN_DIRTY_SYNC
: DN_DIRTY_OPEN
);
1805 ASSERT(dn
->dn_dirtyctx_firstset
== NULL
);
1806 dn
->dn_dirtyctx_firstset
= kmem_alloc(1, KM_SLEEP
);
1808 if (dn
->dn_objset
->os_dsl_dataset
!= NULL
) {
1809 rrw_exit(&dn
->dn_objset
->os_dsl_dataset
->ds_bp_rwlock
,
1813 mutex_exit(&dn
->dn_mtx
);
1815 if (db
->db_blkid
== DMU_SPILL_BLKID
)
1816 dn
->dn_have_spill
= B_TRUE
;
1819 * If this buffer is already dirty, we're done.
1821 drp
= &db
->db_last_dirty
;
1822 ASSERT(*drp
== NULL
|| (*drp
)->dr_txg
<= tx
->tx_txg
||
1823 db
->db
.db_object
== DMU_META_DNODE_OBJECT
);
1824 while ((dr
= *drp
) != NULL
&& dr
->dr_txg
> tx
->tx_txg
)
1826 if (dr
&& dr
->dr_txg
== tx
->tx_txg
) {
1830 mutex_exit(&db
->db_mtx
);
1835 * Only valid if not already dirty.
1837 ASSERT(dn
->dn_object
== 0 ||
1838 dn
->dn_dirtyctx
== DN_UNDIRTIED
|| dn
->dn_dirtyctx
==
1839 (dmu_tx_is_syncing(tx
) ? DN_DIRTY_SYNC
: DN_DIRTY_OPEN
));
1841 ASSERT3U(dn
->dn_nlevels
, >, db
->db_level
);
1844 * We should only be dirtying in syncing context if it's the
1845 * mos or we're initializing the os or it's a special object.
1846 * However, we are allowed to dirty in syncing context provided
1847 * we already dirtied it in open context. Hence we must make
1848 * this assertion only if we're not already dirty.
1851 VERIFY3U(tx
->tx_txg
, <=, spa_final_dirty_txg(os
->os_spa
));
1853 if (dn
->dn_objset
->os_dsl_dataset
!= NULL
)
1854 rrw_enter(&os
->os_dsl_dataset
->ds_bp_rwlock
, RW_READER
, FTAG
);
1855 ASSERT(!dmu_tx_is_syncing(tx
) || DMU_OBJECT_IS_SPECIAL(dn
->dn_object
) ||
1856 os
->os_dsl_dataset
== NULL
|| BP_IS_HOLE(os
->os_rootbp
));
1857 if (dn
->dn_objset
->os_dsl_dataset
!= NULL
)
1858 rrw_exit(&os
->os_dsl_dataset
->ds_bp_rwlock
, FTAG
);
1860 ASSERT(db
->db
.db_size
!= 0);
1862 dprintf_dbuf(db
, "size=%llx\n", (u_longlong_t
)db
->db
.db_size
);
1864 if (db
->db_blkid
!= DMU_BONUS_BLKID
) {
1865 dmu_objset_willuse_space(os
, db
->db
.db_size
, tx
);
1869 * If this buffer is dirty in an old transaction group we need
1870 * to make a copy of it so that the changes we make in this
1871 * transaction group won't leak out when we sync the older txg.
1873 dr
= kmem_zalloc(sizeof (dbuf_dirty_record_t
), KM_SLEEP
);
1874 list_link_init(&dr
->dr_dirty_node
);
1875 if (db
->db_level
== 0) {
1876 void *data_old
= db
->db_buf
;
1878 if (db
->db_state
!= DB_NOFILL
) {
1879 if (db
->db_blkid
== DMU_BONUS_BLKID
) {
1880 dbuf_fix_old_data(db
, tx
->tx_txg
);
1881 data_old
= db
->db
.db_data
;
1882 } else if (db
->db
.db_object
!= DMU_META_DNODE_OBJECT
) {
1884 * Release the data buffer from the cache so
1885 * that we can modify it without impacting
1886 * possible other users of this cached data
1887 * block. Note that indirect blocks and
1888 * private objects are not released until the
1889 * syncing state (since they are only modified
1892 arc_release(db
->db_buf
, db
);
1893 dbuf_fix_old_data(db
, tx
->tx_txg
);
1894 data_old
= db
->db_buf
;
1896 ASSERT(data_old
!= NULL
);
1898 dr
->dt
.dl
.dr_data
= data_old
;
1900 mutex_init(&dr
->dt
.di
.dr_mtx
, NULL
, MUTEX_NOLOCKDEP
, NULL
);
1901 list_create(&dr
->dt
.di
.dr_children
,
1902 sizeof (dbuf_dirty_record_t
),
1903 offsetof(dbuf_dirty_record_t
, dr_dirty_node
));
1905 if (db
->db_blkid
!= DMU_BONUS_BLKID
&& os
->os_dsl_dataset
!= NULL
)
1906 dr
->dr_accounted
= db
->db
.db_size
;
1908 dr
->dr_txg
= tx
->tx_txg
;
1913 * We could have been freed_in_flight between the dbuf_noread
1914 * and dbuf_dirty. We win, as though the dbuf_noread() had
1915 * happened after the free.
1917 if (db
->db_level
== 0 && db
->db_blkid
!= DMU_BONUS_BLKID
&&
1918 db
->db_blkid
!= DMU_SPILL_BLKID
) {
1919 mutex_enter(&dn
->dn_mtx
);
1920 if (dn
->dn_free_ranges
[txgoff
] != NULL
) {
1921 range_tree_clear(dn
->dn_free_ranges
[txgoff
],
1924 mutex_exit(&dn
->dn_mtx
);
1925 db
->db_freed_in_flight
= FALSE
;
1929 * This buffer is now part of this txg
1931 dbuf_add_ref(db
, (void *)(uintptr_t)tx
->tx_txg
);
1932 db
->db_dirtycnt
+= 1;
1933 ASSERT3U(db
->db_dirtycnt
, <=, 3);
1935 mutex_exit(&db
->db_mtx
);
1937 if (db
->db_blkid
== DMU_BONUS_BLKID
||
1938 db
->db_blkid
== DMU_SPILL_BLKID
) {
1939 mutex_enter(&dn
->dn_mtx
);
1940 ASSERT(!list_link_active(&dr
->dr_dirty_node
));
1941 list_insert_tail(&dn
->dn_dirty_records
[txgoff
], dr
);
1942 mutex_exit(&dn
->dn_mtx
);
1943 dnode_setdirty(dn
, tx
);
1949 * The dn_struct_rwlock prevents db_blkptr from changing
1950 * due to a write from syncing context completing
1951 * while we are running, so we want to acquire it before
1952 * looking at db_blkptr.
1954 if (!RW_WRITE_HELD(&dn
->dn_struct_rwlock
)) {
1955 rw_enter(&dn
->dn_struct_rwlock
, RW_READER
);
1956 drop_struct_lock
= TRUE
;
1960 * We need to hold the dn_struct_rwlock to make this assertion,
1961 * because it protects dn_phys / dn_next_nlevels from changing.
1963 ASSERT((dn
->dn_phys
->dn_nlevels
== 0 && db
->db_level
== 0) ||
1964 dn
->dn_phys
->dn_nlevels
> db
->db_level
||
1965 dn
->dn_next_nlevels
[txgoff
] > db
->db_level
||
1966 dn
->dn_next_nlevels
[(tx
->tx_txg
-1) & TXG_MASK
] > db
->db_level
||
1967 dn
->dn_next_nlevels
[(tx
->tx_txg
-2) & TXG_MASK
] > db
->db_level
);
1970 * If we are overwriting a dedup BP, then unless it is snapshotted,
1971 * when we get to syncing context we will need to decrement its
1972 * refcount in the DDT. Prefetch the relevant DDT block so that
1973 * syncing context won't have to wait for the i/o.
1975 ddt_prefetch(os
->os_spa
, db
->db_blkptr
);
1977 if (db
->db_level
== 0) {
1978 dnode_new_blkid(dn
, db
->db_blkid
, tx
, drop_struct_lock
);
1979 ASSERT(dn
->dn_maxblkid
>= db
->db_blkid
);
1982 if (db
->db_level
+1 < dn
->dn_nlevels
) {
1983 dmu_buf_impl_t
*parent
= db
->db_parent
;
1984 dbuf_dirty_record_t
*di
;
1985 int parent_held
= FALSE
;
1987 if (db
->db_parent
== NULL
|| db
->db_parent
== dn
->dn_dbuf
) {
1988 int epbs
= dn
->dn_indblkshift
- SPA_BLKPTRSHIFT
;
1990 parent
= dbuf_hold_level(dn
, db
->db_level
+1,
1991 db
->db_blkid
>> epbs
, FTAG
);
1992 ASSERT(parent
!= NULL
);
1995 if (drop_struct_lock
)
1996 rw_exit(&dn
->dn_struct_rwlock
);
1997 ASSERT3U(db
->db_level
+1, ==, parent
->db_level
);
1998 di
= dbuf_dirty(parent
, tx
);
2000 dbuf_rele(parent
, FTAG
);
2002 mutex_enter(&db
->db_mtx
);
2004 * Since we've dropped the mutex, it's possible that
2005 * dbuf_undirty() might have changed this out from under us.
2007 if (db
->db_last_dirty
== dr
||
2008 dn
->dn_object
== DMU_META_DNODE_OBJECT
) {
2009 mutex_enter(&di
->dt
.di
.dr_mtx
);
2010 ASSERT3U(di
->dr_txg
, ==, tx
->tx_txg
);
2011 ASSERT(!list_link_active(&dr
->dr_dirty_node
));
2012 list_insert_tail(&di
->dt
.di
.dr_children
, dr
);
2013 mutex_exit(&di
->dt
.di
.dr_mtx
);
2016 mutex_exit(&db
->db_mtx
);
2018 ASSERT(db
->db_level
+1 == dn
->dn_nlevels
);
2019 ASSERT(db
->db_blkid
< dn
->dn_nblkptr
);
2020 ASSERT(db
->db_parent
== NULL
|| db
->db_parent
== dn
->dn_dbuf
);
2021 mutex_enter(&dn
->dn_mtx
);
2022 ASSERT(!list_link_active(&dr
->dr_dirty_node
));
2023 list_insert_tail(&dn
->dn_dirty_records
[txgoff
], dr
);
2024 mutex_exit(&dn
->dn_mtx
);
2025 if (drop_struct_lock
)
2026 rw_exit(&dn
->dn_struct_rwlock
);
2029 dnode_setdirty(dn
, tx
);
2035 * Undirty a buffer in the transaction group referenced by the given
2036 * transaction. Return whether this evicted the dbuf.
2039 dbuf_undirty(dmu_buf_impl_t
*db
, dmu_tx_t
*tx
)
2042 uint64_t txg
= tx
->tx_txg
;
2043 dbuf_dirty_record_t
*dr
, **drp
;
2048 * Due to our use of dn_nlevels below, this can only be called
2049 * in open context, unless we are operating on the MOS.
2050 * From syncing context, dn_nlevels may be different from the
2051 * dn_nlevels used when dbuf was dirtied.
2053 ASSERT(db
->db_objset
==
2054 dmu_objset_pool(db
->db_objset
)->dp_meta_objset
||
2055 txg
!= spa_syncing_txg(dmu_objset_spa(db
->db_objset
)));
2056 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
2057 ASSERT0(db
->db_level
);
2058 ASSERT(MUTEX_HELD(&db
->db_mtx
));
2061 * If this buffer is not dirty, we're done.
2063 for (drp
= &db
->db_last_dirty
; (dr
= *drp
) != NULL
; drp
= &dr
->dr_next
)
2064 if (dr
->dr_txg
<= txg
)
2066 if (dr
== NULL
|| dr
->dr_txg
< txg
)
2068 ASSERT(dr
->dr_txg
== txg
);
2069 ASSERT(dr
->dr_dbuf
== db
);
2074 dprintf_dbuf(db
, "size=%llx\n", (u_longlong_t
)db
->db
.db_size
);
2076 ASSERT(db
->db
.db_size
!= 0);
2078 dsl_pool_undirty_space(dmu_objset_pool(dn
->dn_objset
),
2079 dr
->dr_accounted
, txg
);
2084 * Note that there are three places in dbuf_dirty()
2085 * where this dirty record may be put on a list.
2086 * Make sure to do a list_remove corresponding to
2087 * every one of those list_insert calls.
2089 if (dr
->dr_parent
) {
2090 mutex_enter(&dr
->dr_parent
->dt
.di
.dr_mtx
);
2091 list_remove(&dr
->dr_parent
->dt
.di
.dr_children
, dr
);
2092 mutex_exit(&dr
->dr_parent
->dt
.di
.dr_mtx
);
2093 } else if (db
->db_blkid
== DMU_SPILL_BLKID
||
2094 db
->db_level
+ 1 == dn
->dn_nlevels
) {
2095 ASSERT(db
->db_blkptr
== NULL
|| db
->db_parent
== dn
->dn_dbuf
);
2096 mutex_enter(&dn
->dn_mtx
);
2097 list_remove(&dn
->dn_dirty_records
[txg
& TXG_MASK
], dr
);
2098 mutex_exit(&dn
->dn_mtx
);
2102 if (db
->db_state
!= DB_NOFILL
) {
2103 dbuf_unoverride(dr
);
2105 ASSERT(db
->db_buf
!= NULL
);
2106 ASSERT(dr
->dt
.dl
.dr_data
!= NULL
);
2107 if (dr
->dt
.dl
.dr_data
!= db
->db_buf
)
2108 arc_buf_destroy(dr
->dt
.dl
.dr_data
, db
);
2111 kmem_free(dr
, sizeof (dbuf_dirty_record_t
));
2113 ASSERT(db
->db_dirtycnt
> 0);
2114 db
->db_dirtycnt
-= 1;
2116 if (refcount_remove(&db
->db_holds
, (void *)(uintptr_t)txg
) == 0) {
2117 ASSERT(db
->db_state
== DB_NOFILL
|| arc_released(db
->db_buf
));
2126 dmu_buf_will_dirty_impl(dmu_buf_t
*db_fake
, int flags
, dmu_tx_t
*tx
)
2128 dmu_buf_impl_t
*db
= (dmu_buf_impl_t
*)db_fake
;
2130 ASSERT(tx
->tx_txg
!= 0);
2131 ASSERT(!refcount_is_zero(&db
->db_holds
));
2134 * Quick check for dirtyness. For already dirty blocks, this
2135 * reduces runtime of this function by >90%, and overall performance
2136 * by 50% for some workloads (e.g. file deletion with indirect blocks
2139 mutex_enter(&db
->db_mtx
);
2141 dbuf_dirty_record_t
*dr
;
2142 for (dr
= db
->db_last_dirty
;
2143 dr
!= NULL
&& dr
->dr_txg
>= tx
->tx_txg
; dr
= dr
->dr_next
) {
2145 * It's possible that it is already dirty but not cached,
2146 * because there are some calls to dbuf_dirty() that don't
2147 * go through dmu_buf_will_dirty().
2149 if (dr
->dr_txg
== tx
->tx_txg
&& db
->db_state
== DB_CACHED
) {
2150 /* This dbuf is already dirty and cached. */
2152 mutex_exit(&db
->db_mtx
);
2156 mutex_exit(&db
->db_mtx
);
2159 if (RW_WRITE_HELD(&DB_DNODE(db
)->dn_struct_rwlock
))
2160 flags
|= DB_RF_HAVESTRUCT
;
2162 (void) dbuf_read(db
, NULL
, flags
);
2163 (void) dbuf_dirty(db
, tx
);
2167 dmu_buf_will_dirty(dmu_buf_t
*db_fake
, dmu_tx_t
*tx
)
2169 dmu_buf_will_dirty_impl(db_fake
,
2170 DB_RF_MUST_SUCCEED
| DB_RF_NOPREFETCH
, tx
);
2174 dmu_buf_will_not_fill(dmu_buf_t
*db_fake
, dmu_tx_t
*tx
)
2176 dmu_buf_impl_t
*db
= (dmu_buf_impl_t
*)db_fake
;
2178 db
->db_state
= DB_NOFILL
;
2180 dmu_buf_will_fill(db_fake
, tx
);
2184 dmu_buf_will_fill(dmu_buf_t
*db_fake
, dmu_tx_t
*tx
)
2186 dmu_buf_impl_t
*db
= (dmu_buf_impl_t
*)db_fake
;
2188 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
2189 ASSERT(tx
->tx_txg
!= 0);
2190 ASSERT(db
->db_level
== 0);
2191 ASSERT(!refcount_is_zero(&db
->db_holds
));
2193 ASSERT(db
->db
.db_object
!= DMU_META_DNODE_OBJECT
||
2194 dmu_tx_private_ok(tx
));
2197 (void) dbuf_dirty(db
, tx
);
2201 * This function is effectively the same as dmu_buf_will_dirty(), but
2202 * indicates the caller expects raw encrypted data in the db. It will
2203 * also set the raw flag on the created dirty record.
2206 dmu_buf_will_change_crypt_params(dmu_buf_t
*db_fake
, dmu_tx_t
*tx
)
2208 dmu_buf_impl_t
*db
= (dmu_buf_impl_t
*)db_fake
;
2209 dbuf_dirty_record_t
*dr
;
2211 dmu_buf_will_dirty_impl(db_fake
,
2212 DB_RF_MUST_SUCCEED
| DB_RF_NOPREFETCH
| DB_RF_NO_DECRYPT
, tx
);
2214 dr
= db
->db_last_dirty
;
2215 while (dr
!= NULL
&& dr
->dr_txg
> tx
->tx_txg
)
2218 ASSERT3P(dr
, !=, NULL
);
2219 ASSERT3U(dr
->dr_txg
, ==, tx
->tx_txg
);
2220 dr
->dt
.dl
.dr_raw
= B_TRUE
;
2221 db
->db_objset
->os_next_write_raw
[tx
->tx_txg
& TXG_MASK
] = B_TRUE
;
2224 #pragma weak dmu_buf_fill_done = dbuf_fill_done
2227 dbuf_fill_done(dmu_buf_impl_t
*db
, dmu_tx_t
*tx
)
2229 mutex_enter(&db
->db_mtx
);
2232 if (db
->db_state
== DB_FILL
) {
2233 if (db
->db_level
== 0 && db
->db_freed_in_flight
) {
2234 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
2235 /* we were freed while filling */
2236 /* XXX dbuf_undirty? */
2237 bzero(db
->db
.db_data
, db
->db
.db_size
);
2238 db
->db_freed_in_flight
= FALSE
;
2240 db
->db_state
= DB_CACHED
;
2241 cv_broadcast(&db
->db_changed
);
2243 mutex_exit(&db
->db_mtx
);
2247 dmu_buf_write_embedded(dmu_buf_t
*dbuf
, void *data
,
2248 bp_embedded_type_t etype
, enum zio_compress comp
,
2249 int uncompressed_size
, int compressed_size
, int byteorder
,
2252 dmu_buf_impl_t
*db
= (dmu_buf_impl_t
*)dbuf
;
2253 struct dirty_leaf
*dl
;
2254 dmu_object_type_t type
;
2256 if (etype
== BP_EMBEDDED_TYPE_DATA
) {
2257 ASSERT(spa_feature_is_active(dmu_objset_spa(db
->db_objset
),
2258 SPA_FEATURE_EMBEDDED_DATA
));
2262 type
= DB_DNODE(db
)->dn_type
;
2265 ASSERT0(db
->db_level
);
2266 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
2268 dmu_buf_will_not_fill(dbuf
, tx
);
2270 ASSERT3U(db
->db_last_dirty
->dr_txg
, ==, tx
->tx_txg
);
2271 dl
= &db
->db_last_dirty
->dt
.dl
;
2272 encode_embedded_bp_compressed(&dl
->dr_overridden_by
,
2273 data
, comp
, uncompressed_size
, compressed_size
);
2274 BPE_SET_ETYPE(&dl
->dr_overridden_by
, etype
);
2275 BP_SET_TYPE(&dl
->dr_overridden_by
, type
);
2276 BP_SET_LEVEL(&dl
->dr_overridden_by
, 0);
2277 BP_SET_BYTEORDER(&dl
->dr_overridden_by
, byteorder
);
2279 dl
->dr_override_state
= DR_OVERRIDDEN
;
2280 dl
->dr_overridden_by
.blk_birth
= db
->db_last_dirty
->dr_txg
;
2284 * Directly assign a provided arc buf to a given dbuf if it's not referenced
2285 * by anybody except our caller. Otherwise copy arcbuf's contents to dbuf.
2288 dbuf_assign_arcbuf(dmu_buf_impl_t
*db
, arc_buf_t
*buf
, dmu_tx_t
*tx
)
2290 ASSERT(!refcount_is_zero(&db
->db_holds
));
2291 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
2292 ASSERT(db
->db_level
== 0);
2293 ASSERT3U(dbuf_is_metadata(db
), ==, arc_is_metadata(buf
));
2294 ASSERT(buf
!= NULL
);
2295 ASSERT(arc_buf_lsize(buf
) == db
->db
.db_size
);
2296 ASSERT(tx
->tx_txg
!= 0);
2298 arc_return_buf(buf
, db
);
2299 ASSERT(arc_released(buf
));
2301 mutex_enter(&db
->db_mtx
);
2303 while (db
->db_state
== DB_READ
|| db
->db_state
== DB_FILL
)
2304 cv_wait(&db
->db_changed
, &db
->db_mtx
);
2306 ASSERT(db
->db_state
== DB_CACHED
|| db
->db_state
== DB_UNCACHED
);
2308 if (db
->db_state
== DB_CACHED
&&
2309 refcount_count(&db
->db_holds
) - 1 > db
->db_dirtycnt
) {
2311 * In practice, we will never have a case where we have an
2312 * encrypted arc buffer while additional holds exist on the
2313 * dbuf. We don't handle this here so we simply assert that
2316 ASSERT(!arc_is_encrypted(buf
));
2317 mutex_exit(&db
->db_mtx
);
2318 (void) dbuf_dirty(db
, tx
);
2319 bcopy(buf
->b_data
, db
->db
.db_data
, db
->db
.db_size
);
2320 arc_buf_destroy(buf
, db
);
2321 xuio_stat_wbuf_copied();
2325 xuio_stat_wbuf_nocopy();
2326 if (db
->db_state
== DB_CACHED
) {
2327 dbuf_dirty_record_t
*dr
= db
->db_last_dirty
;
2329 ASSERT(db
->db_buf
!= NULL
);
2330 if (dr
!= NULL
&& dr
->dr_txg
== tx
->tx_txg
) {
2331 ASSERT(dr
->dt
.dl
.dr_data
== db
->db_buf
);
2332 IMPLY(arc_is_encrypted(buf
), dr
->dt
.dl
.dr_raw
);
2334 if (!arc_released(db
->db_buf
)) {
2335 ASSERT(dr
->dt
.dl
.dr_override_state
==
2337 arc_release(db
->db_buf
, db
);
2339 dr
->dt
.dl
.dr_data
= buf
;
2340 arc_buf_destroy(db
->db_buf
, db
);
2341 } else if (dr
== NULL
|| dr
->dt
.dl
.dr_data
!= db
->db_buf
) {
2342 arc_release(db
->db_buf
, db
);
2343 arc_buf_destroy(db
->db_buf
, db
);
2347 ASSERT(db
->db_buf
== NULL
);
2348 dbuf_set_data(db
, buf
);
2349 db
->db_state
= DB_FILL
;
2350 mutex_exit(&db
->db_mtx
);
2351 (void) dbuf_dirty(db
, tx
);
2352 dmu_buf_fill_done(&db
->db
, tx
);
2356 dbuf_destroy(dmu_buf_impl_t
*db
)
2359 dmu_buf_impl_t
*parent
= db
->db_parent
;
2360 dmu_buf_impl_t
*dndb
;
2362 ASSERT(MUTEX_HELD(&db
->db_mtx
));
2363 ASSERT(refcount_is_zero(&db
->db_holds
));
2365 if (db
->db_buf
!= NULL
) {
2366 arc_buf_destroy(db
->db_buf
, db
);
2370 if (db
->db_blkid
== DMU_BONUS_BLKID
) {
2371 int slots
= DB_DNODE(db
)->dn_num_slots
;
2372 int bonuslen
= DN_SLOTS_TO_BONUSLEN(slots
);
2373 if (db
->db
.db_data
!= NULL
) {
2374 kmem_free(db
->db
.db_data
, bonuslen
);
2375 arc_space_return(bonuslen
, ARC_SPACE_BONUS
);
2376 db
->db_state
= DB_UNCACHED
;
2380 dbuf_clear_data(db
);
2382 if (multilist_link_active(&db
->db_cache_link
)) {
2383 multilist_remove(dbuf_cache
, db
);
2384 (void) refcount_remove_many(&dbuf_cache_size
,
2385 db
->db
.db_size
, db
);
2386 DBUF_STAT_BUMPDOWN(cache_levels
[db
->db_level
]);
2387 DBUF_STAT_BUMPDOWN(cache_count
);
2388 DBUF_STAT_DECR(cache_levels_bytes
[db
->db_level
],
2392 ASSERT(db
->db_state
== DB_UNCACHED
|| db
->db_state
== DB_NOFILL
);
2393 ASSERT(db
->db_data_pending
== NULL
);
2395 db
->db_state
= DB_EVICTING
;
2396 db
->db_blkptr
= NULL
;
2399 * Now that db_state is DB_EVICTING, nobody else can find this via
2400 * the hash table. We can now drop db_mtx, which allows us to
2401 * acquire the dn_dbufs_mtx.
2403 mutex_exit(&db
->db_mtx
);
2408 if (db
->db_blkid
!= DMU_BONUS_BLKID
) {
2409 boolean_t needlock
= !MUTEX_HELD(&dn
->dn_dbufs_mtx
);
2411 mutex_enter(&dn
->dn_dbufs_mtx
);
2412 avl_remove(&dn
->dn_dbufs
, db
);
2413 atomic_dec_32(&dn
->dn_dbufs_count
);
2417 mutex_exit(&dn
->dn_dbufs_mtx
);
2419 * Decrementing the dbuf count means that the hold corresponding
2420 * to the removed dbuf is no longer discounted in dnode_move(),
2421 * so the dnode cannot be moved until after we release the hold.
2422 * The membar_producer() ensures visibility of the decremented
2423 * value in dnode_move(), since DB_DNODE_EXIT doesn't actually
2427 db
->db_dnode_handle
= NULL
;
2429 dbuf_hash_remove(db
);
2434 ASSERT(refcount_is_zero(&db
->db_holds
));
2436 db
->db_parent
= NULL
;
2438 ASSERT(db
->db_buf
== NULL
);
2439 ASSERT(db
->db
.db_data
== NULL
);
2440 ASSERT(db
->db_hash_next
== NULL
);
2441 ASSERT(db
->db_blkptr
== NULL
);
2442 ASSERT(db
->db_data_pending
== NULL
);
2443 ASSERT(!multilist_link_active(&db
->db_cache_link
));
2445 kmem_cache_free(dbuf_kmem_cache
, db
);
2446 arc_space_return(sizeof (dmu_buf_impl_t
), ARC_SPACE_DBUF
);
2449 * If this dbuf is referenced from an indirect dbuf,
2450 * decrement the ref count on the indirect dbuf.
2452 if (parent
&& parent
!= dndb
)
2453 dbuf_rele(parent
, db
);
2457 * Note: While bpp will always be updated if the function returns success,
2458 * parentp will not be updated if the dnode does not have dn_dbuf filled in;
2459 * this happens when the dnode is the meta-dnode, or a userused or groupused
2462 __attribute__((always_inline
))
2464 dbuf_findbp(dnode_t
*dn
, int level
, uint64_t blkid
, int fail_sparse
,
2465 dmu_buf_impl_t
**parentp
, blkptr_t
**bpp
, struct dbuf_hold_impl_data
*dh
)
2470 ASSERT(blkid
!= DMU_BONUS_BLKID
);
2472 if (blkid
== DMU_SPILL_BLKID
) {
2473 mutex_enter(&dn
->dn_mtx
);
2474 if (dn
->dn_have_spill
&&
2475 (dn
->dn_phys
->dn_flags
& DNODE_FLAG_SPILL_BLKPTR
))
2476 *bpp
= DN_SPILL_BLKPTR(dn
->dn_phys
);
2479 dbuf_add_ref(dn
->dn_dbuf
, NULL
);
2480 *parentp
= dn
->dn_dbuf
;
2481 mutex_exit(&dn
->dn_mtx
);
2486 (dn
->dn_phys
->dn_nlevels
== 0) ? 1 : dn
->dn_phys
->dn_nlevels
;
2487 int epbs
= dn
->dn_indblkshift
- SPA_BLKPTRSHIFT
;
2489 ASSERT3U(level
* epbs
, <, 64);
2490 ASSERT(RW_LOCK_HELD(&dn
->dn_struct_rwlock
));
2492 * This assertion shouldn't trip as long as the max indirect block size
2493 * is less than 1M. The reason for this is that up to that point,
2494 * the number of levels required to address an entire object with blocks
2495 * of size SPA_MINBLOCKSIZE satisfies nlevels * epbs + 1 <= 64. In
2496 * other words, if N * epbs + 1 > 64, then if (N-1) * epbs + 1 > 55
2497 * (i.e. we can address the entire object), objects will all use at most
2498 * N-1 levels and the assertion won't overflow. However, once epbs is
2499 * 13, 4 * 13 + 1 = 53, but 5 * 13 + 1 = 66. Then, 4 levels will not be
2500 * enough to address an entire object, so objects will have 5 levels,
2501 * but then this assertion will overflow.
2503 * All this is to say that if we ever increase DN_MAX_INDBLKSHIFT, we
2504 * need to redo this logic to handle overflows.
2506 ASSERT(level
>= nlevels
||
2507 ((nlevels
- level
- 1) * epbs
) +
2508 highbit64(dn
->dn_phys
->dn_nblkptr
) <= 64);
2509 if (level
>= nlevels
||
2510 blkid
>= ((uint64_t)dn
->dn_phys
->dn_nblkptr
<<
2511 ((nlevels
- level
- 1) * epbs
)) ||
2513 blkid
> (dn
->dn_phys
->dn_maxblkid
>> (level
* epbs
)))) {
2514 /* the buffer has no parent yet */
2515 return (SET_ERROR(ENOENT
));
2516 } else if (level
< nlevels
-1) {
2517 /* this block is referenced from an indirect block */
2520 err
= dbuf_hold_impl(dn
, level
+1,
2521 blkid
>> epbs
, fail_sparse
, FALSE
, NULL
, parentp
);
2523 __dbuf_hold_impl_init(dh
+ 1, dn
, dh
->dh_level
+ 1,
2524 blkid
>> epbs
, fail_sparse
, FALSE
, NULL
,
2525 parentp
, dh
->dh_depth
+ 1);
2526 err
= __dbuf_hold_impl(dh
+ 1);
2530 err
= dbuf_read(*parentp
, NULL
,
2531 (DB_RF_HAVESTRUCT
| DB_RF_NOPREFETCH
| DB_RF_CANFAIL
));
2533 dbuf_rele(*parentp
, NULL
);
2537 *bpp
= ((blkptr_t
*)(*parentp
)->db
.db_data
) +
2538 (blkid
& ((1ULL << epbs
) - 1));
2539 if (blkid
> (dn
->dn_phys
->dn_maxblkid
>> (level
* epbs
)))
2540 ASSERT(BP_IS_HOLE(*bpp
));
2543 /* the block is referenced from the dnode */
2544 ASSERT3U(level
, ==, nlevels
-1);
2545 ASSERT(dn
->dn_phys
->dn_nblkptr
== 0 ||
2546 blkid
< dn
->dn_phys
->dn_nblkptr
);
2548 dbuf_add_ref(dn
->dn_dbuf
, NULL
);
2549 *parentp
= dn
->dn_dbuf
;
2551 *bpp
= &dn
->dn_phys
->dn_blkptr
[blkid
];
2556 static dmu_buf_impl_t
*
2557 dbuf_create(dnode_t
*dn
, uint8_t level
, uint64_t blkid
,
2558 dmu_buf_impl_t
*parent
, blkptr_t
*blkptr
)
2560 objset_t
*os
= dn
->dn_objset
;
2561 dmu_buf_impl_t
*db
, *odb
;
2563 ASSERT(RW_LOCK_HELD(&dn
->dn_struct_rwlock
));
2564 ASSERT(dn
->dn_type
!= DMU_OT_NONE
);
2566 db
= kmem_cache_alloc(dbuf_kmem_cache
, KM_SLEEP
);
2569 db
->db
.db_object
= dn
->dn_object
;
2570 db
->db_level
= level
;
2571 db
->db_blkid
= blkid
;
2572 db
->db_last_dirty
= NULL
;
2573 db
->db_dirtycnt
= 0;
2574 db
->db_dnode_handle
= dn
->dn_handle
;
2575 db
->db_parent
= parent
;
2576 db
->db_blkptr
= blkptr
;
2579 db
->db_user_immediate_evict
= FALSE
;
2580 db
->db_freed_in_flight
= FALSE
;
2581 db
->db_pending_evict
= FALSE
;
2583 if (blkid
== DMU_BONUS_BLKID
) {
2584 ASSERT3P(parent
, ==, dn
->dn_dbuf
);
2585 db
->db
.db_size
= DN_SLOTS_TO_BONUSLEN(dn
->dn_num_slots
) -
2586 (dn
->dn_nblkptr
-1) * sizeof (blkptr_t
);
2587 ASSERT3U(db
->db
.db_size
, >=, dn
->dn_bonuslen
);
2588 db
->db
.db_offset
= DMU_BONUS_BLKID
;
2589 db
->db_state
= DB_UNCACHED
;
2590 /* the bonus dbuf is not placed in the hash table */
2591 arc_space_consume(sizeof (dmu_buf_impl_t
), ARC_SPACE_DBUF
);
2593 } else if (blkid
== DMU_SPILL_BLKID
) {
2594 db
->db
.db_size
= (blkptr
!= NULL
) ?
2595 BP_GET_LSIZE(blkptr
) : SPA_MINBLOCKSIZE
;
2596 db
->db
.db_offset
= 0;
2599 db
->db_level
? 1 << dn
->dn_indblkshift
: dn
->dn_datablksz
;
2600 db
->db
.db_size
= blocksize
;
2601 db
->db
.db_offset
= db
->db_blkid
* blocksize
;
2605 * Hold the dn_dbufs_mtx while we get the new dbuf
2606 * in the hash table *and* added to the dbufs list.
2607 * This prevents a possible deadlock with someone
2608 * trying to look up this dbuf before its added to the
2611 mutex_enter(&dn
->dn_dbufs_mtx
);
2612 db
->db_state
= DB_EVICTING
;
2613 if ((odb
= dbuf_hash_insert(db
)) != NULL
) {
2614 /* someone else inserted it first */
2615 kmem_cache_free(dbuf_kmem_cache
, db
);
2616 mutex_exit(&dn
->dn_dbufs_mtx
);
2617 DBUF_STAT_BUMP(hash_insert_race
);
2620 avl_add(&dn
->dn_dbufs
, db
);
2622 db
->db_state
= DB_UNCACHED
;
2623 mutex_exit(&dn
->dn_dbufs_mtx
);
2624 arc_space_consume(sizeof (dmu_buf_impl_t
), ARC_SPACE_DBUF
);
2626 if (parent
&& parent
!= dn
->dn_dbuf
)
2627 dbuf_add_ref(parent
, db
);
2629 ASSERT(dn
->dn_object
== DMU_META_DNODE_OBJECT
||
2630 refcount_count(&dn
->dn_holds
) > 0);
2631 (void) refcount_add(&dn
->dn_holds
, db
);
2632 atomic_inc_32(&dn
->dn_dbufs_count
);
2634 dprintf_dbuf(db
, "db=%p\n", db
);
2639 typedef struct dbuf_prefetch_arg
{
2640 spa_t
*dpa_spa
; /* The spa to issue the prefetch in. */
2641 zbookmark_phys_t dpa_zb
; /* The target block to prefetch. */
2642 int dpa_epbs
; /* Entries (blkptr_t's) Per Block Shift. */
2643 int dpa_curlevel
; /* The current level that we're reading */
2644 dnode_t
*dpa_dnode
; /* The dnode associated with the prefetch */
2645 zio_priority_t dpa_prio
; /* The priority I/Os should be issued at. */
2646 zio_t
*dpa_zio
; /* The parent zio_t for all prefetches. */
2647 arc_flags_t dpa_aflags
; /* Flags to pass to the final prefetch. */
2648 } dbuf_prefetch_arg_t
;
2651 * Actually issue the prefetch read for the block given.
2654 dbuf_issue_final_prefetch(dbuf_prefetch_arg_t
*dpa
, blkptr_t
*bp
)
2656 if (BP_IS_HOLE(bp
) || BP_IS_EMBEDDED(bp
))
2659 arc_flags_t aflags
=
2660 dpa
->dpa_aflags
| ARC_FLAG_NOWAIT
| ARC_FLAG_PREFETCH
;
2662 ASSERT3U(dpa
->dpa_curlevel
, ==, BP_GET_LEVEL(bp
));
2663 ASSERT3U(dpa
->dpa_curlevel
, ==, dpa
->dpa_zb
.zb_level
);
2664 ASSERT(dpa
->dpa_zio
!= NULL
);
2665 (void) arc_read(dpa
->dpa_zio
, dpa
->dpa_spa
, bp
, NULL
, NULL
,
2666 dpa
->dpa_prio
, ZIO_FLAG_CANFAIL
| ZIO_FLAG_SPECULATIVE
,
2667 &aflags
, &dpa
->dpa_zb
);
2671 * Called when an indirect block above our prefetch target is read in. This
2672 * will either read in the next indirect block down the tree or issue the actual
2673 * prefetch if the next block down is our target.
2676 dbuf_prefetch_indirect_done(zio_t
*zio
, const zbookmark_phys_t
*zb
,
2677 const blkptr_t
*iobp
, arc_buf_t
*abuf
, void *private)
2679 dbuf_prefetch_arg_t
*dpa
= private;
2681 ASSERT3S(dpa
->dpa_zb
.zb_level
, <, dpa
->dpa_curlevel
);
2682 ASSERT3S(dpa
->dpa_curlevel
, >, 0);
2685 * The dpa_dnode is only valid if we are called with a NULL
2686 * zio. This indicates that the arc_read() returned without
2687 * first calling zio_read() to issue a physical read. Once
2688 * a physical read is made the dpa_dnode must be invalidated
2689 * as the locks guarding it may have been dropped. If the
2690 * dpa_dnode is still valid, then we want to add it to the dbuf
2691 * cache. To do so, we must hold the dbuf associated with the block
2692 * we just prefetched, read its contents so that we associate it
2693 * with an arc_buf_t, and then release it.
2696 ASSERT3S(BP_GET_LEVEL(zio
->io_bp
), ==, dpa
->dpa_curlevel
);
2697 if (zio
->io_flags
& ZIO_FLAG_RAW_COMPRESS
) {
2698 ASSERT3U(BP_GET_PSIZE(zio
->io_bp
), ==, zio
->io_size
);
2700 ASSERT3U(BP_GET_LSIZE(zio
->io_bp
), ==, zio
->io_size
);
2702 ASSERT3P(zio
->io_spa
, ==, dpa
->dpa_spa
);
2704 dpa
->dpa_dnode
= NULL
;
2705 } else if (dpa
->dpa_dnode
!= NULL
) {
2706 uint64_t curblkid
= dpa
->dpa_zb
.zb_blkid
>>
2707 (dpa
->dpa_epbs
* (dpa
->dpa_curlevel
-
2708 dpa
->dpa_zb
.zb_level
));
2709 dmu_buf_impl_t
*db
= dbuf_hold_level(dpa
->dpa_dnode
,
2710 dpa
->dpa_curlevel
, curblkid
, FTAG
);
2711 (void) dbuf_read(db
, NULL
,
2712 DB_RF_MUST_SUCCEED
| DB_RF_NOPREFETCH
| DB_RF_HAVESTRUCT
);
2713 dbuf_rele(db
, FTAG
);
2717 kmem_free(dpa
, sizeof (*dpa
));
2721 dpa
->dpa_curlevel
--;
2722 uint64_t nextblkid
= dpa
->dpa_zb
.zb_blkid
>>
2723 (dpa
->dpa_epbs
* (dpa
->dpa_curlevel
- dpa
->dpa_zb
.zb_level
));
2724 blkptr_t
*bp
= ((blkptr_t
*)abuf
->b_data
) +
2725 P2PHASE(nextblkid
, 1ULL << dpa
->dpa_epbs
);
2727 if (BP_IS_HOLE(bp
)) {
2728 kmem_free(dpa
, sizeof (*dpa
));
2729 } else if (dpa
->dpa_curlevel
== dpa
->dpa_zb
.zb_level
) {
2730 ASSERT3U(nextblkid
, ==, dpa
->dpa_zb
.zb_blkid
);
2731 dbuf_issue_final_prefetch(dpa
, bp
);
2732 kmem_free(dpa
, sizeof (*dpa
));
2734 arc_flags_t iter_aflags
= ARC_FLAG_NOWAIT
;
2735 zbookmark_phys_t zb
;
2737 /* flag if L2ARC eligible, l2arc_noprefetch then decides */
2738 if (dpa
->dpa_aflags
& ARC_FLAG_L2CACHE
)
2739 iter_aflags
|= ARC_FLAG_L2CACHE
;
2741 ASSERT3U(dpa
->dpa_curlevel
, ==, BP_GET_LEVEL(bp
));
2743 SET_BOOKMARK(&zb
, dpa
->dpa_zb
.zb_objset
,
2744 dpa
->dpa_zb
.zb_object
, dpa
->dpa_curlevel
, nextblkid
);
2746 (void) arc_read(dpa
->dpa_zio
, dpa
->dpa_spa
,
2747 bp
, dbuf_prefetch_indirect_done
, dpa
, dpa
->dpa_prio
,
2748 ZIO_FLAG_CANFAIL
| ZIO_FLAG_SPECULATIVE
,
2752 arc_buf_destroy(abuf
, private);
2756 * Issue prefetch reads for the given block on the given level. If the indirect
2757 * blocks above that block are not in memory, we will read them in
2758 * asynchronously. As a result, this call never blocks waiting for a read to
2759 * complete. Note that the prefetch might fail if the dataset is encrypted and
2760 * the encryption key is unmapped before the IO completes.
2763 dbuf_prefetch(dnode_t
*dn
, int64_t level
, uint64_t blkid
, zio_priority_t prio
,
2767 int epbs
, nlevels
, curlevel
;
2770 ASSERT(blkid
!= DMU_BONUS_BLKID
);
2771 ASSERT(RW_LOCK_HELD(&dn
->dn_struct_rwlock
));
2773 if (blkid
> dn
->dn_maxblkid
)
2776 if (dnode_block_freed(dn
, blkid
))
2780 * This dnode hasn't been written to disk yet, so there's nothing to
2783 nlevels
= dn
->dn_phys
->dn_nlevels
;
2784 if (level
>= nlevels
|| dn
->dn_phys
->dn_nblkptr
== 0)
2787 epbs
= dn
->dn_phys
->dn_indblkshift
- SPA_BLKPTRSHIFT
;
2788 if (dn
->dn_phys
->dn_maxblkid
< blkid
<< (epbs
* level
))
2791 dmu_buf_impl_t
*db
= dbuf_find(dn
->dn_objset
, dn
->dn_object
,
2794 mutex_exit(&db
->db_mtx
);
2796 * This dbuf already exists. It is either CACHED, or
2797 * (we assume) about to be read or filled.
2803 * Find the closest ancestor (indirect block) of the target block
2804 * that is present in the cache. In this indirect block, we will
2805 * find the bp that is at curlevel, curblkid.
2809 while (curlevel
< nlevels
- 1) {
2810 int parent_level
= curlevel
+ 1;
2811 uint64_t parent_blkid
= curblkid
>> epbs
;
2814 if (dbuf_hold_impl(dn
, parent_level
, parent_blkid
,
2815 FALSE
, TRUE
, FTAG
, &db
) == 0) {
2816 blkptr_t
*bpp
= db
->db_buf
->b_data
;
2817 bp
= bpp
[P2PHASE(curblkid
, 1 << epbs
)];
2818 dbuf_rele(db
, FTAG
);
2822 curlevel
= parent_level
;
2823 curblkid
= parent_blkid
;
2826 if (curlevel
== nlevels
- 1) {
2827 /* No cached indirect blocks found. */
2828 ASSERT3U(curblkid
, <, dn
->dn_phys
->dn_nblkptr
);
2829 bp
= dn
->dn_phys
->dn_blkptr
[curblkid
];
2831 if (BP_IS_HOLE(&bp
))
2834 ASSERT3U(curlevel
, ==, BP_GET_LEVEL(&bp
));
2836 zio_t
*pio
= zio_root(dmu_objset_spa(dn
->dn_objset
), NULL
, NULL
,
2839 dbuf_prefetch_arg_t
*dpa
= kmem_zalloc(sizeof (*dpa
), KM_SLEEP
);
2840 dsl_dataset_t
*ds
= dn
->dn_objset
->os_dsl_dataset
;
2841 SET_BOOKMARK(&dpa
->dpa_zb
, ds
!= NULL
? ds
->ds_object
: DMU_META_OBJSET
,
2842 dn
->dn_object
, level
, blkid
);
2843 dpa
->dpa_curlevel
= curlevel
;
2844 dpa
->dpa_prio
= prio
;
2845 dpa
->dpa_aflags
= aflags
;
2846 dpa
->dpa_spa
= dn
->dn_objset
->os_spa
;
2847 dpa
->dpa_dnode
= dn
;
2848 dpa
->dpa_epbs
= epbs
;
2851 /* flag if L2ARC eligible, l2arc_noprefetch then decides */
2852 if (DNODE_LEVEL_IS_L2CACHEABLE(dn
, level
))
2853 dpa
->dpa_aflags
|= ARC_FLAG_L2CACHE
;
2856 * If we have the indirect just above us, no need to do the asynchronous
2857 * prefetch chain; we'll just run the last step ourselves. If we're at
2858 * a higher level, though, we want to issue the prefetches for all the
2859 * indirect blocks asynchronously, so we can go on with whatever we were
2862 if (curlevel
== level
) {
2863 ASSERT3U(curblkid
, ==, blkid
);
2864 dbuf_issue_final_prefetch(dpa
, &bp
);
2865 kmem_free(dpa
, sizeof (*dpa
));
2867 arc_flags_t iter_aflags
= ARC_FLAG_NOWAIT
;
2868 zbookmark_phys_t zb
;
2870 /* flag if L2ARC eligible, l2arc_noprefetch then decides */
2871 if (DNODE_LEVEL_IS_L2CACHEABLE(dn
, level
))
2872 iter_aflags
|= ARC_FLAG_L2CACHE
;
2874 SET_BOOKMARK(&zb
, ds
!= NULL
? ds
->ds_object
: DMU_META_OBJSET
,
2875 dn
->dn_object
, curlevel
, curblkid
);
2876 (void) arc_read(dpa
->dpa_zio
, dpa
->dpa_spa
,
2877 &bp
, dbuf_prefetch_indirect_done
, dpa
, prio
,
2878 ZIO_FLAG_CANFAIL
| ZIO_FLAG_SPECULATIVE
,
2882 * We use pio here instead of dpa_zio since it's possible that
2883 * dpa may have already been freed.
2888 #define DBUF_HOLD_IMPL_MAX_DEPTH 20
2891 * Helper function for __dbuf_hold_impl() to copy a buffer. Handles
2892 * the case of encrypted, compressed and uncompressed buffers by
2893 * allocating the new buffer, respectively, with arc_alloc_raw_buf(),
2894 * arc_alloc_compressed_buf() or arc_alloc_buf().*
2896 * NOTE: Declared noinline to avoid stack bloat in __dbuf_hold_impl().
2898 noinline
static void
2899 dbuf_hold_copy(struct dbuf_hold_impl_data
*dh
)
2901 dnode_t
*dn
= dh
->dh_dn
;
2902 dmu_buf_impl_t
*db
= dh
->dh_db
;
2903 dbuf_dirty_record_t
*dr
= dh
->dh_dr
;
2904 arc_buf_t
*data
= dr
->dt
.dl
.dr_data
;
2906 enum zio_compress compress_type
= arc_get_compression(data
);
2908 if (arc_is_encrypted(data
)) {
2909 boolean_t byteorder
;
2910 uint8_t salt
[ZIO_DATA_SALT_LEN
];
2911 uint8_t iv
[ZIO_DATA_IV_LEN
];
2912 uint8_t mac
[ZIO_DATA_MAC_LEN
];
2914 arc_get_raw_params(data
, &byteorder
, salt
, iv
, mac
);
2915 dbuf_set_data(db
, arc_alloc_raw_buf(dn
->dn_objset
->os_spa
, db
,
2916 dmu_objset_id(dn
->dn_objset
), byteorder
, salt
, iv
, mac
,
2917 dn
->dn_type
, arc_buf_size(data
), arc_buf_lsize(data
),
2919 } else if (compress_type
!= ZIO_COMPRESS_OFF
) {
2920 dbuf_set_data(db
, arc_alloc_compressed_buf(
2921 dn
->dn_objset
->os_spa
, db
, arc_buf_size(data
),
2922 arc_buf_lsize(data
), compress_type
));
2924 dbuf_set_data(db
, arc_alloc_buf(dn
->dn_objset
->os_spa
, db
,
2925 DBUF_GET_BUFC_TYPE(db
), db
->db
.db_size
));
2928 bcopy(data
->b_data
, db
->db
.db_data
, arc_buf_size(data
));
2932 * Returns with db_holds incremented, and db_mtx not held.
2933 * Note: dn_struct_rwlock must be held.
2936 __dbuf_hold_impl(struct dbuf_hold_impl_data
*dh
)
2938 ASSERT3S(dh
->dh_depth
, <, DBUF_HOLD_IMPL_MAX_DEPTH
);
2939 dh
->dh_parent
= NULL
;
2941 ASSERT(dh
->dh_blkid
!= DMU_BONUS_BLKID
);
2942 ASSERT(RW_LOCK_HELD(&dh
->dh_dn
->dn_struct_rwlock
));
2943 ASSERT3U(dh
->dh_dn
->dn_nlevels
, >, dh
->dh_level
);
2945 *(dh
->dh_dbp
) = NULL
;
2947 /* dbuf_find() returns with db_mtx held */
2948 dh
->dh_db
= dbuf_find(dh
->dh_dn
->dn_objset
, dh
->dh_dn
->dn_object
,
2949 dh
->dh_level
, dh
->dh_blkid
);
2951 if (dh
->dh_db
== NULL
) {
2954 if (dh
->dh_fail_uncached
)
2955 return (SET_ERROR(ENOENT
));
2957 ASSERT3P(dh
->dh_parent
, ==, NULL
);
2958 dh
->dh_err
= dbuf_findbp(dh
->dh_dn
, dh
->dh_level
, dh
->dh_blkid
,
2959 dh
->dh_fail_sparse
, &dh
->dh_parent
, &dh
->dh_bp
, dh
);
2960 if (dh
->dh_fail_sparse
) {
2961 if (dh
->dh_err
== 0 &&
2962 dh
->dh_bp
&& BP_IS_HOLE(dh
->dh_bp
))
2963 dh
->dh_err
= SET_ERROR(ENOENT
);
2966 dbuf_rele(dh
->dh_parent
, NULL
);
2967 return (dh
->dh_err
);
2970 if (dh
->dh_err
&& dh
->dh_err
!= ENOENT
)
2971 return (dh
->dh_err
);
2972 dh
->dh_db
= dbuf_create(dh
->dh_dn
, dh
->dh_level
, dh
->dh_blkid
,
2973 dh
->dh_parent
, dh
->dh_bp
);
2976 if (dh
->dh_fail_uncached
&& dh
->dh_db
->db_state
!= DB_CACHED
) {
2977 mutex_exit(&dh
->dh_db
->db_mtx
);
2978 return (SET_ERROR(ENOENT
));
2981 if (dh
->dh_db
->db_buf
!= NULL
) {
2982 arc_buf_access(dh
->dh_db
->db_buf
);
2983 ASSERT3P(dh
->dh_db
->db
.db_data
, ==, dh
->dh_db
->db_buf
->b_data
);
2986 ASSERT(dh
->dh_db
->db_buf
== NULL
|| arc_referenced(dh
->dh_db
->db_buf
));
2989 * If this buffer is currently syncing out, and we are are
2990 * still referencing it from db_data, we need to make a copy
2991 * of it in case we decide we want to dirty it again in this txg.
2993 if (dh
->dh_db
->db_level
== 0 &&
2994 dh
->dh_db
->db_blkid
!= DMU_BONUS_BLKID
&&
2995 dh
->dh_dn
->dn_object
!= DMU_META_DNODE_OBJECT
&&
2996 dh
->dh_db
->db_state
== DB_CACHED
&& dh
->dh_db
->db_data_pending
) {
2997 dh
->dh_dr
= dh
->dh_db
->db_data_pending
;
2998 if (dh
->dh_dr
->dt
.dl
.dr_data
== dh
->dh_db
->db_buf
)
3002 if (multilist_link_active(&dh
->dh_db
->db_cache_link
)) {
3003 ASSERT(refcount_is_zero(&dh
->dh_db
->db_holds
));
3004 multilist_remove(dbuf_cache
, dh
->dh_db
);
3005 (void) refcount_remove_many(&dbuf_cache_size
,
3006 dh
->dh_db
->db
.db_size
, dh
->dh_db
);
3007 DBUF_STAT_BUMPDOWN(cache_levels
[dh
->dh_db
->db_level
]);
3008 DBUF_STAT_BUMPDOWN(cache_count
);
3009 DBUF_STAT_DECR(cache_levels_bytes
[dh
->dh_db
->db_level
],
3010 dh
->dh_db
->db
.db_size
);
3012 (void) refcount_add(&dh
->dh_db
->db_holds
, dh
->dh_tag
);
3013 DBUF_VERIFY(dh
->dh_db
);
3014 mutex_exit(&dh
->dh_db
->db_mtx
);
3016 /* NOTE: we can't rele the parent until after we drop the db_mtx */
3018 dbuf_rele(dh
->dh_parent
, NULL
);
3020 ASSERT3P(DB_DNODE(dh
->dh_db
), ==, dh
->dh_dn
);
3021 ASSERT3U(dh
->dh_db
->db_blkid
, ==, dh
->dh_blkid
);
3022 ASSERT3U(dh
->dh_db
->db_level
, ==, dh
->dh_level
);
3023 *(dh
->dh_dbp
) = dh
->dh_db
;
3029 * The following code preserves the recursive function dbuf_hold_impl()
3030 * but moves the local variables AND function arguments to the heap to
3031 * minimize the stack frame size. Enough space is initially allocated
3032 * on the stack for 20 levels of recursion.
3035 dbuf_hold_impl(dnode_t
*dn
, uint8_t level
, uint64_t blkid
,
3036 boolean_t fail_sparse
, boolean_t fail_uncached
,
3037 void *tag
, dmu_buf_impl_t
**dbp
)
3039 struct dbuf_hold_impl_data
*dh
;
3042 dh
= kmem_alloc(sizeof (struct dbuf_hold_impl_data
) *
3043 DBUF_HOLD_IMPL_MAX_DEPTH
, KM_SLEEP
);
3044 __dbuf_hold_impl_init(dh
, dn
, level
, blkid
, fail_sparse
,
3045 fail_uncached
, tag
, dbp
, 0);
3047 error
= __dbuf_hold_impl(dh
);
3049 kmem_free(dh
, sizeof (struct dbuf_hold_impl_data
) *
3050 DBUF_HOLD_IMPL_MAX_DEPTH
);
3056 __dbuf_hold_impl_init(struct dbuf_hold_impl_data
*dh
,
3057 dnode_t
*dn
, uint8_t level
, uint64_t blkid
,
3058 boolean_t fail_sparse
, boolean_t fail_uncached
,
3059 void *tag
, dmu_buf_impl_t
**dbp
, int depth
)
3062 dh
->dh_level
= level
;
3063 dh
->dh_blkid
= blkid
;
3065 dh
->dh_fail_sparse
= fail_sparse
;
3066 dh
->dh_fail_uncached
= fail_uncached
;
3072 dh
->dh_parent
= NULL
;
3077 dh
->dh_depth
= depth
;
3081 dbuf_hold(dnode_t
*dn
, uint64_t blkid
, void *tag
)
3083 return (dbuf_hold_level(dn
, 0, blkid
, tag
));
3087 dbuf_hold_level(dnode_t
*dn
, int level
, uint64_t blkid
, void *tag
)
3090 int err
= dbuf_hold_impl(dn
, level
, blkid
, FALSE
, FALSE
, tag
, &db
);
3091 return (err
? NULL
: db
);
3095 dbuf_create_bonus(dnode_t
*dn
)
3097 ASSERT(RW_WRITE_HELD(&dn
->dn_struct_rwlock
));
3099 ASSERT(dn
->dn_bonus
== NULL
);
3100 dn
->dn_bonus
= dbuf_create(dn
, 0, DMU_BONUS_BLKID
, dn
->dn_dbuf
, NULL
);
3104 dbuf_spill_set_blksz(dmu_buf_t
*db_fake
, uint64_t blksz
, dmu_tx_t
*tx
)
3106 dmu_buf_impl_t
*db
= (dmu_buf_impl_t
*)db_fake
;
3109 if (db
->db_blkid
!= DMU_SPILL_BLKID
)
3110 return (SET_ERROR(ENOTSUP
));
3112 blksz
= SPA_MINBLOCKSIZE
;
3113 ASSERT3U(blksz
, <=, spa_maxblocksize(dmu_objset_spa(db
->db_objset
)));
3114 blksz
= P2ROUNDUP(blksz
, SPA_MINBLOCKSIZE
);
3118 rw_enter(&dn
->dn_struct_rwlock
, RW_WRITER
);
3119 dbuf_new_size(db
, blksz
, tx
);
3120 rw_exit(&dn
->dn_struct_rwlock
);
3127 dbuf_rm_spill(dnode_t
*dn
, dmu_tx_t
*tx
)
3129 dbuf_free_range(dn
, DMU_SPILL_BLKID
, DMU_SPILL_BLKID
, tx
);
3132 #pragma weak dmu_buf_add_ref = dbuf_add_ref
3134 dbuf_add_ref(dmu_buf_impl_t
*db
, void *tag
)
3136 int64_t holds
= refcount_add(&db
->db_holds
, tag
);
3137 VERIFY3S(holds
, >, 1);
3140 #pragma weak dmu_buf_try_add_ref = dbuf_try_add_ref
3142 dbuf_try_add_ref(dmu_buf_t
*db_fake
, objset_t
*os
, uint64_t obj
, uint64_t blkid
,
3145 dmu_buf_impl_t
*db
= (dmu_buf_impl_t
*)db_fake
;
3146 dmu_buf_impl_t
*found_db
;
3147 boolean_t result
= B_FALSE
;
3149 if (blkid
== DMU_BONUS_BLKID
)
3150 found_db
= dbuf_find_bonus(os
, obj
);
3152 found_db
= dbuf_find(os
, obj
, 0, blkid
);
3154 if (found_db
!= NULL
) {
3155 if (db
== found_db
&& dbuf_refcount(db
) > db
->db_dirtycnt
) {
3156 (void) refcount_add(&db
->db_holds
, tag
);
3159 mutex_exit(&found_db
->db_mtx
);
3165 * If you call dbuf_rele() you had better not be referencing the dnode handle
3166 * unless you have some other direct or indirect hold on the dnode. (An indirect
3167 * hold is a hold on one of the dnode's dbufs, including the bonus buffer.)
3168 * Without that, the dbuf_rele() could lead to a dnode_rele() followed by the
3169 * dnode's parent dbuf evicting its dnode handles.
3172 dbuf_rele(dmu_buf_impl_t
*db
, void *tag
)
3174 mutex_enter(&db
->db_mtx
);
3175 dbuf_rele_and_unlock(db
, tag
);
3179 dmu_buf_rele(dmu_buf_t
*db
, void *tag
)
3181 dbuf_rele((dmu_buf_impl_t
*)db
, tag
);
3185 * dbuf_rele() for an already-locked dbuf. This is necessary to allow
3186 * db_dirtycnt and db_holds to be updated atomically.
3189 dbuf_rele_and_unlock(dmu_buf_impl_t
*db
, void *tag
)
3193 ASSERT(MUTEX_HELD(&db
->db_mtx
));
3197 * Remove the reference to the dbuf before removing its hold on the
3198 * dnode so we can guarantee in dnode_move() that a referenced bonus
3199 * buffer has a corresponding dnode hold.
3201 holds
= refcount_remove(&db
->db_holds
, tag
);
3205 * We can't freeze indirects if there is a possibility that they
3206 * may be modified in the current syncing context.
3208 if (db
->db_buf
!= NULL
&&
3209 holds
== (db
->db_level
== 0 ? db
->db_dirtycnt
: 0)) {
3210 arc_buf_freeze(db
->db_buf
);
3213 if (holds
== db
->db_dirtycnt
&&
3214 db
->db_level
== 0 && db
->db_user_immediate_evict
)
3215 dbuf_evict_user(db
);
3218 if (db
->db_blkid
== DMU_BONUS_BLKID
) {
3220 boolean_t evict_dbuf
= db
->db_pending_evict
;
3223 * If the dnode moves here, we cannot cross this
3224 * barrier until the move completes.
3229 atomic_dec_32(&dn
->dn_dbufs_count
);
3232 * Decrementing the dbuf count means that the bonus
3233 * buffer's dnode hold is no longer discounted in
3234 * dnode_move(). The dnode cannot move until after
3235 * the dnode_rele() below.
3240 * Do not reference db after its lock is dropped.
3241 * Another thread may evict it.
3243 mutex_exit(&db
->db_mtx
);
3246 dnode_evict_bonus(dn
);
3249 } else if (db
->db_buf
== NULL
) {
3251 * This is a special case: we never associated this
3252 * dbuf with any data allocated from the ARC.
3254 ASSERT(db
->db_state
== DB_UNCACHED
||
3255 db
->db_state
== DB_NOFILL
);
3257 } else if (arc_released(db
->db_buf
)) {
3259 * This dbuf has anonymous data associated with it.
3263 boolean_t do_arc_evict
= B_FALSE
;
3265 spa_t
*spa
= dmu_objset_spa(db
->db_objset
);
3267 if (!DBUF_IS_CACHEABLE(db
) &&
3268 db
->db_blkptr
!= NULL
&&
3269 !BP_IS_HOLE(db
->db_blkptr
) &&
3270 !BP_IS_EMBEDDED(db
->db_blkptr
)) {
3271 do_arc_evict
= B_TRUE
;
3272 bp
= *db
->db_blkptr
;
3275 if (!DBUF_IS_CACHEABLE(db
) ||
3276 db
->db_pending_evict
) {
3278 } else if (!multilist_link_active(&db
->db_cache_link
)) {
3279 multilist_insert(dbuf_cache
, db
);
3280 (void) refcount_add_many(&dbuf_cache_size
,
3281 db
->db
.db_size
, db
);
3282 DBUF_STAT_BUMP(cache_levels
[db
->db_level
]);
3283 DBUF_STAT_BUMP(cache_count
);
3284 DBUF_STAT_INCR(cache_levels_bytes
[db
->db_level
],
3286 DBUF_STAT_MAX(cache_size_bytes_max
,
3287 refcount_count(&dbuf_cache_size
));
3288 mutex_exit(&db
->db_mtx
);
3290 dbuf_evict_notify();
3294 arc_freed(spa
, &bp
);
3297 mutex_exit(&db
->db_mtx
);
3302 #pragma weak dmu_buf_refcount = dbuf_refcount
3304 dbuf_refcount(dmu_buf_impl_t
*db
)
3306 return (refcount_count(&db
->db_holds
));
3310 dmu_buf_replace_user(dmu_buf_t
*db_fake
, dmu_buf_user_t
*old_user
,
3311 dmu_buf_user_t
*new_user
)
3313 dmu_buf_impl_t
*db
= (dmu_buf_impl_t
*)db_fake
;
3315 mutex_enter(&db
->db_mtx
);
3316 dbuf_verify_user(db
, DBVU_NOT_EVICTING
);
3317 if (db
->db_user
== old_user
)
3318 db
->db_user
= new_user
;
3320 old_user
= db
->db_user
;
3321 dbuf_verify_user(db
, DBVU_NOT_EVICTING
);
3322 mutex_exit(&db
->db_mtx
);
3328 dmu_buf_set_user(dmu_buf_t
*db_fake
, dmu_buf_user_t
*user
)
3330 return (dmu_buf_replace_user(db_fake
, NULL
, user
));
3334 dmu_buf_set_user_ie(dmu_buf_t
*db_fake
, dmu_buf_user_t
*user
)
3336 dmu_buf_impl_t
*db
= (dmu_buf_impl_t
*)db_fake
;
3338 db
->db_user_immediate_evict
= TRUE
;
3339 return (dmu_buf_set_user(db_fake
, user
));
3343 dmu_buf_remove_user(dmu_buf_t
*db_fake
, dmu_buf_user_t
*user
)
3345 return (dmu_buf_replace_user(db_fake
, user
, NULL
));
3349 dmu_buf_get_user(dmu_buf_t
*db_fake
)
3351 dmu_buf_impl_t
*db
= (dmu_buf_impl_t
*)db_fake
;
3353 dbuf_verify_user(db
, DBVU_NOT_EVICTING
);
3354 return (db
->db_user
);
3358 dmu_buf_user_evict_wait()
3360 taskq_wait(dbu_evict_taskq
);
3364 dmu_buf_get_blkptr(dmu_buf_t
*db
)
3366 dmu_buf_impl_t
*dbi
= (dmu_buf_impl_t
*)db
;
3367 return (dbi
->db_blkptr
);
3371 dmu_buf_get_objset(dmu_buf_t
*db
)
3373 dmu_buf_impl_t
*dbi
= (dmu_buf_impl_t
*)db
;
3374 return (dbi
->db_objset
);
3378 dmu_buf_dnode_enter(dmu_buf_t
*db
)
3380 dmu_buf_impl_t
*dbi
= (dmu_buf_impl_t
*)db
;
3381 DB_DNODE_ENTER(dbi
);
3382 return (DB_DNODE(dbi
));
3386 dmu_buf_dnode_exit(dmu_buf_t
*db
)
3388 dmu_buf_impl_t
*dbi
= (dmu_buf_impl_t
*)db
;
3393 dbuf_check_blkptr(dnode_t
*dn
, dmu_buf_impl_t
*db
)
3395 /* ASSERT(dmu_tx_is_syncing(tx) */
3396 ASSERT(MUTEX_HELD(&db
->db_mtx
));
3398 if (db
->db_blkptr
!= NULL
)
3401 if (db
->db_blkid
== DMU_SPILL_BLKID
) {
3402 db
->db_blkptr
= DN_SPILL_BLKPTR(dn
->dn_phys
);
3403 BP_ZERO(db
->db_blkptr
);
3406 if (db
->db_level
== dn
->dn_phys
->dn_nlevels
-1) {
3408 * This buffer was allocated at a time when there was
3409 * no available blkptrs from the dnode, or it was
3410 * inappropriate to hook it in (i.e., nlevels mis-match).
3412 ASSERT(db
->db_blkid
< dn
->dn_phys
->dn_nblkptr
);
3413 ASSERT(db
->db_parent
== NULL
);
3414 db
->db_parent
= dn
->dn_dbuf
;
3415 db
->db_blkptr
= &dn
->dn_phys
->dn_blkptr
[db
->db_blkid
];
3418 dmu_buf_impl_t
*parent
= db
->db_parent
;
3419 int epbs
= dn
->dn_phys
->dn_indblkshift
- SPA_BLKPTRSHIFT
;
3421 ASSERT(dn
->dn_phys
->dn_nlevels
> 1);
3422 if (parent
== NULL
) {
3423 mutex_exit(&db
->db_mtx
);
3424 rw_enter(&dn
->dn_struct_rwlock
, RW_READER
);
3425 parent
= dbuf_hold_level(dn
, db
->db_level
+ 1,
3426 db
->db_blkid
>> epbs
, db
);
3427 rw_exit(&dn
->dn_struct_rwlock
);
3428 mutex_enter(&db
->db_mtx
);
3429 db
->db_parent
= parent
;
3431 db
->db_blkptr
= (blkptr_t
*)parent
->db
.db_data
+
3432 (db
->db_blkid
& ((1ULL << epbs
) - 1));
3438 * Ensure the dbuf's data is untransformed if the associated dirty
3439 * record requires it. This is used by dbuf_sync_leaf() to ensure
3440 * that a dnode block is decrypted before we write new data to it.
3441 * For raw writes we assert that the buffer is already encrypted.
3444 dbuf_check_crypt(dbuf_dirty_record_t
*dr
)
3447 dmu_buf_impl_t
*db
= dr
->dr_dbuf
;
3449 ASSERT(MUTEX_HELD(&db
->db_mtx
));
3451 if (!dr
->dt
.dl
.dr_raw
&& arc_is_encrypted(db
->db_buf
)) {
3453 * Unfortunately, there is currently no mechanism for
3454 * syncing context to handle decryption errors. An error
3455 * here is only possible if an attacker maliciously
3456 * changed a dnode block and updated the associated
3457 * checksums going up the block tree.
3459 err
= arc_untransform(db
->db_buf
, db
->db_objset
->os_spa
,
3460 dmu_objset_id(db
->db_objset
), B_TRUE
);
3462 panic("Invalid dnode block MAC");
3463 } else if (dr
->dt
.dl
.dr_raw
) {
3465 * Writing raw encrypted data requires the db's arc buffer
3466 * to be converted to raw by the caller.
3468 ASSERT(arc_is_encrypted(db
->db_buf
));
3473 * dbuf_sync_indirect() is called recursively from dbuf_sync_list() so it
3474 * is critical the we not allow the compiler to inline this function in to
3475 * dbuf_sync_list() thereby drastically bloating the stack usage.
3477 noinline
static void
3478 dbuf_sync_indirect(dbuf_dirty_record_t
*dr
, dmu_tx_t
*tx
)
3480 dmu_buf_impl_t
*db
= dr
->dr_dbuf
;
3484 ASSERT(dmu_tx_is_syncing(tx
));
3486 dprintf_dbuf_bp(db
, db
->db_blkptr
, "blkptr=%p", db
->db_blkptr
);
3488 mutex_enter(&db
->db_mtx
);
3490 ASSERT(db
->db_level
> 0);
3493 /* Read the block if it hasn't been read yet. */
3494 if (db
->db_buf
== NULL
) {
3495 mutex_exit(&db
->db_mtx
);
3496 (void) dbuf_read(db
, NULL
, DB_RF_MUST_SUCCEED
);
3497 mutex_enter(&db
->db_mtx
);
3499 ASSERT3U(db
->db_state
, ==, DB_CACHED
);
3500 ASSERT(db
->db_buf
!= NULL
);
3504 /* Indirect block size must match what the dnode thinks it is. */
3505 ASSERT3U(db
->db
.db_size
, ==, 1<<dn
->dn_phys
->dn_indblkshift
);
3506 dbuf_check_blkptr(dn
, db
);
3509 /* Provide the pending dirty record to child dbufs */
3510 db
->db_data_pending
= dr
;
3512 mutex_exit(&db
->db_mtx
);
3513 dbuf_write(dr
, db
->db_buf
, tx
);
3516 mutex_enter(&dr
->dt
.di
.dr_mtx
);
3517 dbuf_sync_list(&dr
->dt
.di
.dr_children
, db
->db_level
- 1, tx
);
3518 ASSERT(list_head(&dr
->dt
.di
.dr_children
) == NULL
);
3519 mutex_exit(&dr
->dt
.di
.dr_mtx
);
3524 * dbuf_sync_leaf() is called recursively from dbuf_sync_list() so it is
3525 * critical the we not allow the compiler to inline this function in to
3526 * dbuf_sync_list() thereby drastically bloating the stack usage.
3528 noinline
static void
3529 dbuf_sync_leaf(dbuf_dirty_record_t
*dr
, dmu_tx_t
*tx
)
3531 arc_buf_t
**datap
= &dr
->dt
.dl
.dr_data
;
3532 dmu_buf_impl_t
*db
= dr
->dr_dbuf
;
3535 uint64_t txg
= tx
->tx_txg
;
3537 ASSERT(dmu_tx_is_syncing(tx
));
3539 dprintf_dbuf_bp(db
, db
->db_blkptr
, "blkptr=%p", db
->db_blkptr
);
3541 mutex_enter(&db
->db_mtx
);
3543 * To be synced, we must be dirtied. But we
3544 * might have been freed after the dirty.
3546 if (db
->db_state
== DB_UNCACHED
) {
3547 /* This buffer has been freed since it was dirtied */
3548 ASSERT(db
->db
.db_data
== NULL
);
3549 } else if (db
->db_state
== DB_FILL
) {
3550 /* This buffer was freed and is now being re-filled */
3551 ASSERT(db
->db
.db_data
!= dr
->dt
.dl
.dr_data
);
3553 ASSERT(db
->db_state
== DB_CACHED
|| db
->db_state
== DB_NOFILL
);
3560 if (db
->db_blkid
== DMU_SPILL_BLKID
) {
3561 mutex_enter(&dn
->dn_mtx
);
3562 if (!(dn
->dn_phys
->dn_flags
& DNODE_FLAG_SPILL_BLKPTR
)) {
3564 * In the previous transaction group, the bonus buffer
3565 * was entirely used to store the attributes for the
3566 * dnode which overrode the dn_spill field. However,
3567 * when adding more attributes to the file a spill
3568 * block was required to hold the extra attributes.
3570 * Make sure to clear the garbage left in the dn_spill
3571 * field from the previous attributes in the bonus
3572 * buffer. Otherwise, after writing out the spill
3573 * block to the new allocated dva, it will free
3574 * the old block pointed to by the invalid dn_spill.
3576 db
->db_blkptr
= NULL
;
3578 dn
->dn_phys
->dn_flags
|= DNODE_FLAG_SPILL_BLKPTR
;
3579 mutex_exit(&dn
->dn_mtx
);
3583 * If this is a bonus buffer, simply copy the bonus data into the
3584 * dnode. It will be written out when the dnode is synced (and it
3585 * will be synced, since it must have been dirty for dbuf_sync to
3588 if (db
->db_blkid
== DMU_BONUS_BLKID
) {
3589 dbuf_dirty_record_t
**drp
;
3591 ASSERT(*datap
!= NULL
);
3592 ASSERT0(db
->db_level
);
3593 ASSERT3U(DN_MAX_BONUS_LEN(dn
->dn_phys
), <=,
3594 DN_SLOTS_TO_BONUSLEN(dn
->dn_phys
->dn_extra_slots
+ 1));
3595 bcopy(*datap
, DN_BONUS(dn
->dn_phys
),
3596 DN_MAX_BONUS_LEN(dn
->dn_phys
));
3599 if (*datap
!= db
->db
.db_data
) {
3600 int slots
= DB_DNODE(db
)->dn_num_slots
;
3601 int bonuslen
= DN_SLOTS_TO_BONUSLEN(slots
);
3602 kmem_free(*datap
, bonuslen
);
3603 arc_space_return(bonuslen
, ARC_SPACE_BONUS
);
3605 db
->db_data_pending
= NULL
;
3606 drp
= &db
->db_last_dirty
;
3608 drp
= &(*drp
)->dr_next
;
3609 ASSERT(dr
->dr_next
== NULL
);
3610 ASSERT(dr
->dr_dbuf
== db
);
3612 if (dr
->dr_dbuf
->db_level
!= 0) {
3613 mutex_destroy(&dr
->dt
.di
.dr_mtx
);
3614 list_destroy(&dr
->dt
.di
.dr_children
);
3616 kmem_free(dr
, sizeof (dbuf_dirty_record_t
));
3617 ASSERT(db
->db_dirtycnt
> 0);
3618 db
->db_dirtycnt
-= 1;
3619 dbuf_rele_and_unlock(db
, (void *)(uintptr_t)txg
);
3626 * This function may have dropped the db_mtx lock allowing a dmu_sync
3627 * operation to sneak in. As a result, we need to ensure that we
3628 * don't check the dr_override_state until we have returned from
3629 * dbuf_check_blkptr.
3631 dbuf_check_blkptr(dn
, db
);
3634 * If this buffer is in the middle of an immediate write,
3635 * wait for the synchronous IO to complete.
3637 while (dr
->dt
.dl
.dr_override_state
== DR_IN_DMU_SYNC
) {
3638 ASSERT(dn
->dn_object
!= DMU_META_DNODE_OBJECT
);
3639 cv_wait(&db
->db_changed
, &db
->db_mtx
);
3640 ASSERT(dr
->dt
.dl
.dr_override_state
!= DR_NOT_OVERRIDDEN
);
3644 * If this is a dnode block, ensure it is appropriately encrypted
3645 * or decrypted, depending on what we are writing to it this txg.
3647 if (os
->os_encrypted
&& dn
->dn_object
== DMU_META_DNODE_OBJECT
)
3648 dbuf_check_crypt(dr
);
3650 if (db
->db_state
!= DB_NOFILL
&&
3651 dn
->dn_object
!= DMU_META_DNODE_OBJECT
&&
3652 refcount_count(&db
->db_holds
) > 1 &&
3653 dr
->dt
.dl
.dr_override_state
!= DR_OVERRIDDEN
&&
3654 *datap
== db
->db_buf
) {
3656 * If this buffer is currently "in use" (i.e., there
3657 * are active holds and db_data still references it),
3658 * then make a copy before we start the write so that
3659 * any modifications from the open txg will not leak
3662 * NOTE: this copy does not need to be made for
3663 * objects only modified in the syncing context (e.g.
3664 * DNONE_DNODE blocks).
3666 int psize
= arc_buf_size(*datap
);
3667 int lsize
= arc_buf_lsize(*datap
);
3668 arc_buf_contents_t type
= DBUF_GET_BUFC_TYPE(db
);
3669 enum zio_compress compress_type
= arc_get_compression(*datap
);
3671 if (arc_is_encrypted(*datap
)) {
3672 boolean_t byteorder
;
3673 uint8_t salt
[ZIO_DATA_SALT_LEN
];
3674 uint8_t iv
[ZIO_DATA_IV_LEN
];
3675 uint8_t mac
[ZIO_DATA_MAC_LEN
];
3677 arc_get_raw_params(*datap
, &byteorder
, salt
, iv
, mac
);
3678 *datap
= arc_alloc_raw_buf(os
->os_spa
, db
,
3679 dmu_objset_id(os
), byteorder
, salt
, iv
, mac
,
3680 dn
->dn_type
, psize
, lsize
, compress_type
);
3681 } else if (compress_type
!= ZIO_COMPRESS_OFF
) {
3682 ASSERT3U(type
, ==, ARC_BUFC_DATA
);
3683 *datap
= arc_alloc_compressed_buf(os
->os_spa
, db
,
3684 psize
, lsize
, compress_type
);
3686 *datap
= arc_alloc_buf(os
->os_spa
, db
, type
, psize
);
3688 bcopy(db
->db
.db_data
, (*datap
)->b_data
, psize
);
3690 db
->db_data_pending
= dr
;
3692 mutex_exit(&db
->db_mtx
);
3694 dbuf_write(dr
, *datap
, tx
);
3696 ASSERT(!list_link_active(&dr
->dr_dirty_node
));
3697 if (dn
->dn_object
== DMU_META_DNODE_OBJECT
) {
3698 list_insert_tail(&dn
->dn_dirty_records
[txg
&TXG_MASK
], dr
);
3702 * Although zio_nowait() does not "wait for an IO", it does
3703 * initiate the IO. If this is an empty write it seems plausible
3704 * that the IO could actually be completed before the nowait
3705 * returns. We need to DB_DNODE_EXIT() first in case
3706 * zio_nowait() invalidates the dbuf.
3709 zio_nowait(dr
->dr_zio
);
3714 dbuf_sync_list(list_t
*list
, int level
, dmu_tx_t
*tx
)
3716 dbuf_dirty_record_t
*dr
;
3718 while ((dr
= list_head(list
))) {
3719 if (dr
->dr_zio
!= NULL
) {
3721 * If we find an already initialized zio then we
3722 * are processing the meta-dnode, and we have finished.
3723 * The dbufs for all dnodes are put back on the list
3724 * during processing, so that we can zio_wait()
3725 * these IOs after initiating all child IOs.
3727 ASSERT3U(dr
->dr_dbuf
->db
.db_object
, ==,
3728 DMU_META_DNODE_OBJECT
);
3731 if (dr
->dr_dbuf
->db_blkid
!= DMU_BONUS_BLKID
&&
3732 dr
->dr_dbuf
->db_blkid
!= DMU_SPILL_BLKID
) {
3733 VERIFY3U(dr
->dr_dbuf
->db_level
, ==, level
);
3735 list_remove(list
, dr
);
3736 if (dr
->dr_dbuf
->db_level
> 0)
3737 dbuf_sync_indirect(dr
, tx
);
3739 dbuf_sync_leaf(dr
, tx
);
3745 dbuf_write_ready(zio_t
*zio
, arc_buf_t
*buf
, void *vdb
)
3747 dmu_buf_impl_t
*db
= vdb
;
3749 blkptr_t
*bp
= zio
->io_bp
;
3750 blkptr_t
*bp_orig
= &zio
->io_bp_orig
;
3751 spa_t
*spa
= zio
->io_spa
;
3756 ASSERT3P(db
->db_blkptr
, !=, NULL
);
3757 ASSERT3P(&db
->db_data_pending
->dr_bp_copy
, ==, bp
);
3761 delta
= bp_get_dsize_sync(spa
, bp
) - bp_get_dsize_sync(spa
, bp_orig
);
3762 dnode_diduse_space(dn
, delta
- zio
->io_prev_space_delta
);
3763 zio
->io_prev_space_delta
= delta
;
3765 if (bp
->blk_birth
!= 0) {
3766 ASSERT((db
->db_blkid
!= DMU_SPILL_BLKID
&&
3767 BP_GET_TYPE(bp
) == dn
->dn_type
) ||
3768 (db
->db_blkid
== DMU_SPILL_BLKID
&&
3769 BP_GET_TYPE(bp
) == dn
->dn_bonustype
) ||
3770 BP_IS_EMBEDDED(bp
));
3771 ASSERT(BP_GET_LEVEL(bp
) == db
->db_level
);
3774 mutex_enter(&db
->db_mtx
);
3777 if (db
->db_blkid
== DMU_SPILL_BLKID
) {
3778 ASSERT(dn
->dn_phys
->dn_flags
& DNODE_FLAG_SPILL_BLKPTR
);
3779 ASSERT(!(BP_IS_HOLE(bp
)) &&
3780 db
->db_blkptr
== DN_SPILL_BLKPTR(dn
->dn_phys
));
3784 if (db
->db_level
== 0) {
3785 mutex_enter(&dn
->dn_mtx
);
3786 if (db
->db_blkid
> dn
->dn_phys
->dn_maxblkid
&&
3787 db
->db_blkid
!= DMU_SPILL_BLKID
)
3788 dn
->dn_phys
->dn_maxblkid
= db
->db_blkid
;
3789 mutex_exit(&dn
->dn_mtx
);
3791 if (dn
->dn_type
== DMU_OT_DNODE
) {
3793 while (i
< db
->db
.db_size
) {
3795 (void *)(((char *)db
->db
.db_data
) + i
);
3797 i
+= DNODE_MIN_SIZE
;
3798 if (dnp
->dn_type
!= DMU_OT_NONE
) {
3800 i
+= dnp
->dn_extra_slots
*
3805 if (BP_IS_HOLE(bp
)) {
3812 blkptr_t
*ibp
= db
->db
.db_data
;
3813 ASSERT3U(db
->db
.db_size
, ==, 1<<dn
->dn_phys
->dn_indblkshift
);
3814 for (i
= db
->db
.db_size
>> SPA_BLKPTRSHIFT
; i
> 0; i
--, ibp
++) {
3815 if (BP_IS_HOLE(ibp
))
3817 fill
+= BP_GET_FILL(ibp
);
3822 if (!BP_IS_EMBEDDED(bp
))
3823 BP_SET_FILL(bp
, fill
);
3825 mutex_exit(&db
->db_mtx
);
3827 rw_enter(&dn
->dn_struct_rwlock
, RW_WRITER
);
3828 *db
->db_blkptr
= *bp
;
3829 rw_exit(&dn
->dn_struct_rwlock
);
3834 * This function gets called just prior to running through the compression
3835 * stage of the zio pipeline. If we're an indirect block comprised of only
3836 * holes, then we want this indirect to be compressed away to a hole. In
3837 * order to do that we must zero out any information about the holes that
3838 * this indirect points to prior to before we try to compress it.
3841 dbuf_write_children_ready(zio_t
*zio
, arc_buf_t
*buf
, void *vdb
)
3843 dmu_buf_impl_t
*db
= vdb
;
3846 unsigned int epbs
, i
;
3848 ASSERT3U(db
->db_level
, >, 0);
3851 epbs
= dn
->dn_phys
->dn_indblkshift
- SPA_BLKPTRSHIFT
;
3852 ASSERT3U(epbs
, <, 31);
3854 /* Determine if all our children are holes */
3855 for (i
= 0, bp
= db
->db
.db_data
; i
< 1ULL << epbs
; i
++, bp
++) {
3856 if (!BP_IS_HOLE(bp
))
3861 * If all the children are holes, then zero them all out so that
3862 * we may get compressed away.
3864 if (i
== 1ULL << epbs
) {
3866 * We only found holes. Grab the rwlock to prevent
3867 * anybody from reading the blocks we're about to
3870 rw_enter(&dn
->dn_struct_rwlock
, RW_WRITER
);
3871 bzero(db
->db
.db_data
, db
->db
.db_size
);
3872 rw_exit(&dn
->dn_struct_rwlock
);
3878 * The SPA will call this callback several times for each zio - once
3879 * for every physical child i/o (zio->io_phys_children times). This
3880 * allows the DMU to monitor the progress of each logical i/o. For example,
3881 * there may be 2 copies of an indirect block, or many fragments of a RAID-Z
3882 * block. There may be a long delay before all copies/fragments are completed,
3883 * so this callback allows us to retire dirty space gradually, as the physical
3888 dbuf_write_physdone(zio_t
*zio
, arc_buf_t
*buf
, void *arg
)
3890 dmu_buf_impl_t
*db
= arg
;
3891 objset_t
*os
= db
->db_objset
;
3892 dsl_pool_t
*dp
= dmu_objset_pool(os
);
3893 dbuf_dirty_record_t
*dr
;
3896 dr
= db
->db_data_pending
;
3897 ASSERT3U(dr
->dr_txg
, ==, zio
->io_txg
);
3900 * The callback will be called io_phys_children times. Retire one
3901 * portion of our dirty space each time we are called. Any rounding
3902 * error will be cleaned up by dsl_pool_sync()'s call to
3903 * dsl_pool_undirty_space().
3905 delta
= dr
->dr_accounted
/ zio
->io_phys_children
;
3906 dsl_pool_undirty_space(dp
, delta
, zio
->io_txg
);
3911 dbuf_write_done(zio_t
*zio
, arc_buf_t
*buf
, void *vdb
)
3913 dmu_buf_impl_t
*db
= vdb
;
3914 blkptr_t
*bp_orig
= &zio
->io_bp_orig
;
3915 blkptr_t
*bp
= db
->db_blkptr
;
3916 objset_t
*os
= db
->db_objset
;
3917 dmu_tx_t
*tx
= os
->os_synctx
;
3918 dbuf_dirty_record_t
**drp
, *dr
;
3920 ASSERT0(zio
->io_error
);
3921 ASSERT(db
->db_blkptr
== bp
);
3924 * For nopwrites and rewrites we ensure that the bp matches our
3925 * original and bypass all the accounting.
3927 if (zio
->io_flags
& (ZIO_FLAG_IO_REWRITE
| ZIO_FLAG_NOPWRITE
)) {
3928 ASSERT(BP_EQUAL(bp
, bp_orig
));
3930 dsl_dataset_t
*ds
= os
->os_dsl_dataset
;
3931 (void) dsl_dataset_block_kill(ds
, bp_orig
, tx
, B_TRUE
);
3932 dsl_dataset_block_born(ds
, bp
, tx
);
3935 mutex_enter(&db
->db_mtx
);
3939 drp
= &db
->db_last_dirty
;
3940 while ((dr
= *drp
) != db
->db_data_pending
)
3942 ASSERT(!list_link_active(&dr
->dr_dirty_node
));
3943 ASSERT(dr
->dr_dbuf
== db
);
3944 ASSERT(dr
->dr_next
== NULL
);
3948 if (db
->db_blkid
== DMU_SPILL_BLKID
) {
3953 ASSERT(dn
->dn_phys
->dn_flags
& DNODE_FLAG_SPILL_BLKPTR
);
3954 ASSERT(!(BP_IS_HOLE(db
->db_blkptr
)) &&
3955 db
->db_blkptr
== DN_SPILL_BLKPTR(dn
->dn_phys
));
3960 if (db
->db_level
== 0) {
3961 ASSERT(db
->db_blkid
!= DMU_BONUS_BLKID
);
3962 ASSERT(dr
->dt
.dl
.dr_override_state
== DR_NOT_OVERRIDDEN
);
3963 if (db
->db_state
!= DB_NOFILL
) {
3964 if (dr
->dt
.dl
.dr_data
!= db
->db_buf
)
3965 arc_buf_destroy(dr
->dt
.dl
.dr_data
, db
);
3972 ASSERT(list_head(&dr
->dt
.di
.dr_children
) == NULL
);
3973 ASSERT3U(db
->db
.db_size
, ==, 1 << dn
->dn_phys
->dn_indblkshift
);
3974 if (!BP_IS_HOLE(db
->db_blkptr
)) {
3975 ASSERTV(int epbs
= dn
->dn_phys
->dn_indblkshift
-
3977 ASSERT3U(db
->db_blkid
, <=,
3978 dn
->dn_phys
->dn_maxblkid
>> (db
->db_level
* epbs
));
3979 ASSERT3U(BP_GET_LSIZE(db
->db_blkptr
), ==,
3983 mutex_destroy(&dr
->dt
.di
.dr_mtx
);
3984 list_destroy(&dr
->dt
.di
.dr_children
);
3986 kmem_free(dr
, sizeof (dbuf_dirty_record_t
));
3988 cv_broadcast(&db
->db_changed
);
3989 ASSERT(db
->db_dirtycnt
> 0);
3990 db
->db_dirtycnt
-= 1;
3991 db
->db_data_pending
= NULL
;
3992 dbuf_rele_and_unlock(db
, (void *)(uintptr_t)tx
->tx_txg
);
3996 dbuf_write_nofill_ready(zio_t
*zio
)
3998 dbuf_write_ready(zio
, NULL
, zio
->io_private
);
4002 dbuf_write_nofill_done(zio_t
*zio
)
4004 dbuf_write_done(zio
, NULL
, zio
->io_private
);
4008 dbuf_write_override_ready(zio_t
*zio
)
4010 dbuf_dirty_record_t
*dr
= zio
->io_private
;
4011 dmu_buf_impl_t
*db
= dr
->dr_dbuf
;
4013 dbuf_write_ready(zio
, NULL
, db
);
4017 dbuf_write_override_done(zio_t
*zio
)
4019 dbuf_dirty_record_t
*dr
= zio
->io_private
;
4020 dmu_buf_impl_t
*db
= dr
->dr_dbuf
;
4021 blkptr_t
*obp
= &dr
->dt
.dl
.dr_overridden_by
;
4023 mutex_enter(&db
->db_mtx
);
4024 if (!BP_EQUAL(zio
->io_bp
, obp
)) {
4025 if (!BP_IS_HOLE(obp
))
4026 dsl_free(spa_get_dsl(zio
->io_spa
), zio
->io_txg
, obp
);
4027 arc_release(dr
->dt
.dl
.dr_data
, db
);
4029 mutex_exit(&db
->db_mtx
);
4031 dbuf_write_done(zio
, NULL
, db
);
4033 if (zio
->io_abd
!= NULL
)
4034 abd_put(zio
->io_abd
);
4037 /* Issue I/O to commit a dirty buffer to disk. */
4039 dbuf_write(dbuf_dirty_record_t
*dr
, arc_buf_t
*data
, dmu_tx_t
*tx
)
4041 dmu_buf_impl_t
*db
= dr
->dr_dbuf
;
4044 dmu_buf_impl_t
*parent
= db
->db_parent
;
4045 uint64_t txg
= tx
->tx_txg
;
4046 zbookmark_phys_t zb
;
4051 ASSERT(dmu_tx_is_syncing(tx
));
4057 if (db
->db_state
!= DB_NOFILL
) {
4058 if (db
->db_level
> 0 || dn
->dn_type
== DMU_OT_DNODE
) {
4060 * Private object buffers are released here rather
4061 * than in dbuf_dirty() since they are only modified
4062 * in the syncing context and we don't want the
4063 * overhead of making multiple copies of the data.
4065 if (BP_IS_HOLE(db
->db_blkptr
)) {
4068 dbuf_release_bp(db
);
4073 if (parent
!= dn
->dn_dbuf
) {
4074 /* Our parent is an indirect block. */
4075 /* We have a dirty parent that has been scheduled for write. */
4076 ASSERT(parent
&& parent
->db_data_pending
);
4077 /* Our parent's buffer is one level closer to the dnode. */
4078 ASSERT(db
->db_level
== parent
->db_level
-1);
4080 * We're about to modify our parent's db_data by modifying
4081 * our block pointer, so the parent must be released.
4083 ASSERT(arc_released(parent
->db_buf
));
4084 zio
= parent
->db_data_pending
->dr_zio
;
4086 /* Our parent is the dnode itself. */
4087 ASSERT((db
->db_level
== dn
->dn_phys
->dn_nlevels
-1 &&
4088 db
->db_blkid
!= DMU_SPILL_BLKID
) ||
4089 (db
->db_blkid
== DMU_SPILL_BLKID
&& db
->db_level
== 0));
4090 if (db
->db_blkid
!= DMU_SPILL_BLKID
)
4091 ASSERT3P(db
->db_blkptr
, ==,
4092 &dn
->dn_phys
->dn_blkptr
[db
->db_blkid
]);
4096 ASSERT(db
->db_level
== 0 || data
== db
->db_buf
);
4097 ASSERT3U(db
->db_blkptr
->blk_birth
, <=, txg
);
4100 SET_BOOKMARK(&zb
, os
->os_dsl_dataset
?
4101 os
->os_dsl_dataset
->ds_object
: DMU_META_OBJSET
,
4102 db
->db
.db_object
, db
->db_level
, db
->db_blkid
);
4104 if (db
->db_blkid
== DMU_SPILL_BLKID
)
4106 wp_flag
|= (db
->db_state
== DB_NOFILL
) ? WP_NOFILL
: 0;
4108 dmu_write_policy(os
, dn
, db
->db_level
, wp_flag
, &zp
);
4112 * We copy the blkptr now (rather than when we instantiate the dirty
4113 * record), because its value can change between open context and
4114 * syncing context. We do not need to hold dn_struct_rwlock to read
4115 * db_blkptr because we are in syncing context.
4117 dr
->dr_bp_copy
= *db
->db_blkptr
;
4119 if (db
->db_level
== 0 &&
4120 dr
->dt
.dl
.dr_override_state
== DR_OVERRIDDEN
) {
4122 * The BP for this block has been provided by open context
4123 * (by dmu_sync() or dmu_buf_write_embedded()).
4125 abd_t
*contents
= (data
!= NULL
) ?
4126 abd_get_from_buf(data
->b_data
, arc_buf_size(data
)) : NULL
;
4128 dr
->dr_zio
= zio_write(zio
, os
->os_spa
, txg
,
4129 &dr
->dr_bp_copy
, contents
, db
->db
.db_size
, db
->db
.db_size
,
4130 &zp
, dbuf_write_override_ready
, NULL
, NULL
,
4131 dbuf_write_override_done
,
4132 dr
, ZIO_PRIORITY_ASYNC_WRITE
, ZIO_FLAG_MUSTSUCCEED
, &zb
);
4133 mutex_enter(&db
->db_mtx
);
4134 dr
->dt
.dl
.dr_override_state
= DR_NOT_OVERRIDDEN
;
4135 zio_write_override(dr
->dr_zio
, &dr
->dt
.dl
.dr_overridden_by
,
4136 dr
->dt
.dl
.dr_copies
, dr
->dt
.dl
.dr_nopwrite
);
4137 mutex_exit(&db
->db_mtx
);
4138 } else if (db
->db_state
== DB_NOFILL
) {
4139 ASSERT(zp
.zp_checksum
== ZIO_CHECKSUM_OFF
||
4140 zp
.zp_checksum
== ZIO_CHECKSUM_NOPARITY
);
4141 dr
->dr_zio
= zio_write(zio
, os
->os_spa
, txg
,
4142 &dr
->dr_bp_copy
, NULL
, db
->db
.db_size
, db
->db
.db_size
, &zp
,
4143 dbuf_write_nofill_ready
, NULL
, NULL
,
4144 dbuf_write_nofill_done
, db
,
4145 ZIO_PRIORITY_ASYNC_WRITE
,
4146 ZIO_FLAG_MUSTSUCCEED
| ZIO_FLAG_NODATA
, &zb
);
4148 ASSERT(arc_released(data
));
4151 * For indirect blocks, we want to setup the children
4152 * ready callback so that we can properly handle an indirect
4153 * block that only contains holes.
4155 arc_write_done_func_t
*children_ready_cb
= NULL
;
4156 if (db
->db_level
!= 0)
4157 children_ready_cb
= dbuf_write_children_ready
;
4159 dr
->dr_zio
= arc_write(zio
, os
->os_spa
, txg
,
4160 &dr
->dr_bp_copy
, data
, DBUF_IS_L2CACHEABLE(db
),
4161 &zp
, dbuf_write_ready
,
4162 children_ready_cb
, dbuf_write_physdone
,
4163 dbuf_write_done
, db
, ZIO_PRIORITY_ASYNC_WRITE
,
4164 ZIO_FLAG_MUSTSUCCEED
, &zb
);
4168 #if defined(_KERNEL) && defined(HAVE_SPL)
4169 EXPORT_SYMBOL(dbuf_find
);
4170 EXPORT_SYMBOL(dbuf_is_metadata
);
4171 EXPORT_SYMBOL(dbuf_destroy
);
4172 EXPORT_SYMBOL(dbuf_loan_arcbuf
);
4173 EXPORT_SYMBOL(dbuf_whichblock
);
4174 EXPORT_SYMBOL(dbuf_read
);
4175 EXPORT_SYMBOL(dbuf_unoverride
);
4176 EXPORT_SYMBOL(dbuf_free_range
);
4177 EXPORT_SYMBOL(dbuf_new_size
);
4178 EXPORT_SYMBOL(dbuf_release_bp
);
4179 EXPORT_SYMBOL(dbuf_dirty
);
4180 EXPORT_SYMBOL(dmu_buf_will_change_crypt_params
);
4181 EXPORT_SYMBOL(dmu_buf_will_dirty
);
4182 EXPORT_SYMBOL(dmu_buf_will_not_fill
);
4183 EXPORT_SYMBOL(dmu_buf_will_fill
);
4184 EXPORT_SYMBOL(dmu_buf_fill_done
);
4185 EXPORT_SYMBOL(dmu_buf_rele
);
4186 EXPORT_SYMBOL(dbuf_assign_arcbuf
);
4187 EXPORT_SYMBOL(dbuf_prefetch
);
4188 EXPORT_SYMBOL(dbuf_hold_impl
);
4189 EXPORT_SYMBOL(dbuf_hold
);
4190 EXPORT_SYMBOL(dbuf_hold_level
);
4191 EXPORT_SYMBOL(dbuf_create_bonus
);
4192 EXPORT_SYMBOL(dbuf_spill_set_blksz
);
4193 EXPORT_SYMBOL(dbuf_rm_spill
);
4194 EXPORT_SYMBOL(dbuf_add_ref
);
4195 EXPORT_SYMBOL(dbuf_rele
);
4196 EXPORT_SYMBOL(dbuf_rele_and_unlock
);
4197 EXPORT_SYMBOL(dbuf_refcount
);
4198 EXPORT_SYMBOL(dbuf_sync_list
);
4199 EXPORT_SYMBOL(dmu_buf_set_user
);
4200 EXPORT_SYMBOL(dmu_buf_set_user_ie
);
4201 EXPORT_SYMBOL(dmu_buf_get_user
);
4202 EXPORT_SYMBOL(dmu_buf_get_blkptr
);
4205 module_param(dbuf_cache_max_bytes
, ulong
, 0644);
4206 MODULE_PARM_DESC(dbuf_cache_max_bytes
,
4207 "Maximum size in bytes of the dbuf cache.");
4209 module_param(dbuf_cache_hiwater_pct
, uint
, 0644);
4210 MODULE_PARM_DESC(dbuf_cache_hiwater_pct
,
4211 "Percentage over dbuf_cache_max_bytes when dbufs must be evicted "
4214 module_param(dbuf_cache_lowater_pct
, uint
, 0644);
4215 MODULE_PARM_DESC(dbuf_cache_lowater_pct
,
4216 "Percentage below dbuf_cache_max_bytes when the evict thread stops "
4219 module_param(dbuf_cache_max_shift
, int, 0644);
4220 MODULE_PARM_DESC(dbuf_cache_max_shift
,
4221 "Cap the size of the dbuf cache to a log2 fraction of arc size.");