1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2012, 2020 by Delphix. All rights reserved.
24 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
25 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
26 */
27
28 #ifndef _SYS_DBUF_H
29 #define _SYS_DBUF_H
30
31 #include <sys/dmu.h>
32 #include <sys/spa.h>
33 #include <sys/txg.h>
34 #include <sys/zio.h>
35 #include <sys/arc.h>
36 #include <sys/zfs_context.h>
37 #include <sys/zfs_refcount.h>
38 #include <sys/zrlock.h>
39 #include <sys/multilist.h>
40
41 #ifdef __cplusplus
42 extern "C" {
43 #endif
44
45 #define IN_DMU_SYNC 2
46
47 /*
48 * define flags for dbuf_read
49 */
50
51 #define DB_RF_MUST_SUCCEED (1 << 0)
52 #define DB_RF_CANFAIL (1 << 1)
53 #define DB_RF_HAVESTRUCT (1 << 2)
54 #define DB_RF_NOPREFETCH (1 << 3)
55 #define DB_RF_NEVERWAIT (1 << 4)
56 #define DB_RF_CACHED (1 << 5)
57 #define DB_RF_NO_DECRYPT (1 << 6)
58
59 /*
60 * The simplified state transition diagram for dbufs looks like:
61 *
62 * +----> READ ----+
63 * | |
64 * | V
65 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free)
66 * | ^ ^
67 * | | |
68 * +----> FILL ----+ |
69 * | |
70 * | |
71 * +--------> NOFILL -------+
72 *
73 * DB_SEARCH is an invalid state for a dbuf. It is used by dbuf_free_range
74 * to find all dbufs in a range of a dnode and must be less than any other
75 * dbuf_states_t (see comment on dn_dbufs in dnode.h).
76 */
77 typedef enum dbuf_states {
78 DB_SEARCH = -1,
79 DB_UNCACHED,
80 DB_FILL,
81 DB_NOFILL,
82 DB_READ,
83 DB_CACHED,
84 DB_EVICTING
85 } dbuf_states_t;
86
87 typedef enum dbuf_cached_state {
88 DB_NO_CACHE = -1,
89 DB_DBUF_CACHE,
90 DB_DBUF_METADATA_CACHE,
91 DB_CACHE_MAX
92 } dbuf_cached_state_t;
93
94 struct dnode;
95 struct dmu_tx;
96
97 /*
98 * level = 0 means the user data
99 * level = 1 means the single indirect block
100 * etc.
101 */
102
103 struct dmu_buf_impl;
104
105 typedef enum override_states {
106 DR_NOT_OVERRIDDEN,
107 DR_IN_DMU_SYNC,
108 DR_OVERRIDDEN
109 } override_states_t;
110
111 typedef enum db_lock_type {
112 DLT_NONE,
113 DLT_PARENT,
114 DLT_OBJSET
115 } db_lock_type_t;
116
117 typedef struct dbuf_dirty_record {
118 /* link on our parents dirty list */
119 list_node_t dr_dirty_node;
120
121 /* transaction group this data will sync in */
122 uint64_t dr_txg;
123
124 /* zio of outstanding write IO */
125 zio_t *dr_zio;
126
127 /* pointer back to our dbuf */
128 struct dmu_buf_impl *dr_dbuf;
129
130 /* list link for dbuf dirty records */
131 list_node_t dr_dbuf_node;
132
133 /*
134 * The dnode we are part of. Note that the dnode can not be moved or
135 * evicted due to the hold that's added by dnode_setdirty() or
136 * dmu_objset_sync_dnodes(), and released by dnode_rele_task() or
137 * userquota_updates_task(). This hold is necessary for
138 * dirty_lightweight_leaf-type dirty records, which don't have a hold
139 * on a dbuf.
140 */
141 dnode_t *dr_dnode;
142
143 /* pointer to parent dirty record */
144 struct dbuf_dirty_record *dr_parent;
145
146 /* How much space was changed to dsl_pool_dirty_space() for this? */
147 unsigned int dr_accounted;
148
149 /* A copy of the bp that points to us */
150 blkptr_t dr_bp_copy;
151
152 union dirty_types {
153 struct dirty_indirect {
154
155 /* protect access to list */
156 kmutex_t dr_mtx;
157
158 /* Our list of dirty children */
159 list_t dr_children;
160 } di;
161 struct dirty_leaf {
162
163 /*
164 * dr_data is set when we dirty the buffer
165 * so that we can retain the pointer even if it
166 * gets COW'd in a subsequent transaction group.
167 */
168 arc_buf_t *dr_data;
169 blkptr_t dr_overridden_by;
170 override_states_t dr_override_state;
171 uint8_t dr_copies;
172 boolean_t dr_nopwrite;
173 boolean_t dr_has_raw_params;
174
175 /*
176 * If dr_has_raw_params is set, the following crypt
177 * params will be set on the BP that's written.
178 */
179 boolean_t dr_byteorder;
180 uint8_t dr_salt[ZIO_DATA_SALT_LEN];
181 uint8_t dr_iv[ZIO_DATA_IV_LEN];
182 uint8_t dr_mac[ZIO_DATA_MAC_LEN];
183 } dl;
184 struct dirty_lightweight_leaf {
185 /*
186 * This dirty record refers to a leaf (level=0)
187 * block, whose dbuf has not been instantiated for
188 * performance reasons.
189 */
190 uint64_t dr_blkid;
191 abd_t *dr_abd;
192 zio_prop_t dr_props;
193 enum zio_flag dr_flags;
194 } dll;
195 } dt;
196 } dbuf_dirty_record_t;
197
198 typedef struct dmu_buf_impl {
199 /*
200 * The following members are immutable, with the exception of
201 * db.db_data, which is protected by db_mtx.
202 */
203
204 /* the publicly visible structure */
205 dmu_buf_t db;
206
207 /* the objset we belong to */
208 struct objset *db_objset;
209
210 /*
211 * handle to safely access the dnode we belong to (NULL when evicted)
212 */
213 struct dnode_handle *db_dnode_handle;
214
215 /*
216 * our parent buffer; if the dnode points to us directly,
217 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf
218 * only accessed by sync thread ???
219 * (NULL when evicted)
220 * May change from NULL to non-NULL under the protection of db_mtx
221 * (see dbuf_check_blkptr())
222 */
223 struct dmu_buf_impl *db_parent;
224
225 /*
226 * link for hash table of all dmu_buf_impl_t's
227 */
228 struct dmu_buf_impl *db_hash_next;
229
230 /*
231 * Our link on the owner dnodes's dn_dbufs list.
232 * Protected by its dn_dbufs_mtx. Should be on the same cache line
233 * as db_level and db_blkid for the best avl_add() performance.
234 */
235 avl_node_t db_link;
236
237 /* our block number */
238 uint64_t db_blkid;
239
240 /*
241 * Pointer to the blkptr_t which points to us. May be NULL if we
242 * don't have one yet. (NULL when evicted)
243 */
244 blkptr_t *db_blkptr;
245
246 /*
247 * Our indirection level. Data buffers have db_level==0.
248 * Indirect buffers which point to data buffers have
249 * db_level==1. etc. Buffers which contain dnodes have
250 * db_level==0, since the dnodes are stored in a file.
251 */
252 uint8_t db_level;
253
254 /*
255 * Protects db_buf's contents if they contain an indirect block or data
256 * block of the meta-dnode. We use this lock to protect the structure of
257 * the block tree. This means that when modifying this dbuf's data, we
258 * grab its rwlock. When modifying its parent's data (including the
259 * blkptr to this dbuf), we grab the parent's rwlock. The lock ordering
260 * for this lock is:
261 * 1) dn_struct_rwlock
262 * 2) db_rwlock
263 * We don't currently grab multiple dbufs' db_rwlocks at once.
264 */
265 krwlock_t db_rwlock;
266
267 /* buffer holding our data */
268 arc_buf_t *db_buf;
269
270 /* db_mtx protects the members below */
271 kmutex_t db_mtx;
272
273 /*
274 * Current state of the buffer
275 */
276 dbuf_states_t db_state;
277
278 /*
279 * Refcount accessed by dmu_buf_{hold,rele}.
280 * If nonzero, the buffer can't be destroyed.
281 * Protected by db_mtx.
282 */
283 zfs_refcount_t db_holds;
284
285 kcondvar_t db_changed;
286 dbuf_dirty_record_t *db_data_pending;
287
288 /* List of dirty records for the buffer sorted newest to oldest. */
289 list_t db_dirty_records;
290
291 /* Link in dbuf_cache or dbuf_metadata_cache */
292 multilist_node_t db_cache_link;
293
294 /* Tells us which dbuf cache this dbuf is in, if any */
295 dbuf_cached_state_t db_caching_status;
296
297 /* Data which is unique to data (leaf) blocks: */
298
299 /* User callback information. */
300 dmu_buf_user_t *db_user;
301
302 /*
303 * Evict user data as soon as the dirty and reference
304 * counts are equal.
305 */
306 uint8_t db_user_immediate_evict;
307
308 /*
309 * This block was freed while a read or write was
310 * active.
311 */
312 uint8_t db_freed_in_flight;
313
314 /*
315 * dnode_evict_dbufs() or dnode_evict_bonus() tried to
316 * evict this dbuf, but couldn't due to outstanding
317 * references. Evict once the refcount drops to 0.
318 */
319 uint8_t db_pending_evict;
320
321 uint8_t db_dirtycnt;
322 } dmu_buf_impl_t;
323
324 /* Note: the dbuf hash table is exposed only for the mdb module */
325 #define DBUF_MUTEXES 8192
326 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)])
327 typedef struct dbuf_hash_table {
328 uint64_t hash_table_mask;
329 dmu_buf_impl_t **hash_table;
330 kmutex_t hash_mutexes[DBUF_MUTEXES];
331 } dbuf_hash_table_t;
332
333 typedef void (*dbuf_prefetch_fn)(void *, boolean_t);
334
335 uint64_t dbuf_whichblock(const struct dnode *di, const int64_t level,
336 const uint64_t offset);
337
338 void dbuf_create_bonus(struct dnode *dn);
339 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx);
340
341 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx);
342
343 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag);
344 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid,
345 void *tag);
346 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid,
347 boolean_t fail_sparse, boolean_t fail_uncached,
348 void *tag, dmu_buf_impl_t **dbp);
349
350 int dbuf_prefetch_impl(struct dnode *dn, int64_t level, uint64_t blkid,
351 zio_priority_t prio, arc_flags_t aflags, dbuf_prefetch_fn cb,
352 void *arg);
353 int dbuf_prefetch(struct dnode *dn, int64_t level, uint64_t blkid,
354 zio_priority_t prio, arc_flags_t aflags);
355
356 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag);
357 boolean_t dbuf_try_add_ref(dmu_buf_t *db, objset_t *os, uint64_t obj,
358 uint64_t blkid, void *tag);
359 uint64_t dbuf_refcount(dmu_buf_impl_t *db);
360
361 void dbuf_rele(dmu_buf_impl_t *db, void *tag);
362 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag, boolean_t evicting);
363
364 dmu_buf_impl_t *dbuf_find(struct objset *os, uint64_t object, uint8_t level,
365 uint64_t blkid);
366
367 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags);
368 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
369 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx);
370 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx);
371 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx);
372 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
373 dbuf_dirty_record_t *dbuf_dirty_lightweight(dnode_t *dn, uint64_t blkid,
374 dmu_tx_t *tx);
375 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db);
376 void dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data,
377 bp_embedded_type_t etype, enum zio_compress comp,
378 int uncompressed_size, int compressed_size, int byteorder, dmu_tx_t *tx);
379
380 int dmu_lightweight_write_by_dnode(dnode_t *dn, uint64_t offset, abd_t *abd,
381 const struct zio_prop *zp, enum zio_flag flags, dmu_tx_t *tx);
382
383 void dmu_buf_redact(dmu_buf_t *dbuf, dmu_tx_t *tx);
384 void dbuf_destroy(dmu_buf_impl_t *db);
385
386 void dbuf_unoverride(dbuf_dirty_record_t *dr);
387 void dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx);
388 void dbuf_release_bp(dmu_buf_impl_t *db);
389 db_lock_type_t dmu_buf_lock_parent(dmu_buf_impl_t *db, krw_t rw, void *tag);
390 void dmu_buf_unlock_parent(dmu_buf_impl_t *db, db_lock_type_t type, void *tag);
391
392 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end,
393 struct dmu_tx *);
394
395 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx);
396
397 void dbuf_stats_init(dbuf_hash_table_t *hash);
398 void dbuf_stats_destroy(void);
399
400 int dbuf_dnode_findbp(dnode_t *dn, uint64_t level, uint64_t blkid,
401 blkptr_t *bp, uint16_t *datablkszsec, uint8_t *indblkshift);
402
403 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode)
404 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock)
405 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db)))
406 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db)))
407 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db)))
408
409 void dbuf_init(void);
410 void dbuf_fini(void);
411
412 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db);
413
414 static inline dbuf_dirty_record_t *
dbuf_find_dirty_lte(dmu_buf_impl_t * db,uint64_t txg)415 dbuf_find_dirty_lte(dmu_buf_impl_t *db, uint64_t txg)
416 {
417 dbuf_dirty_record_t *dr;
418
419 for (dr = list_head(&db->db_dirty_records);
420 dr != NULL && dr->dr_txg > txg;
421 dr = list_next(&db->db_dirty_records, dr))
422 continue;
423 return (dr);
424 }
425
426 static inline dbuf_dirty_record_t *
dbuf_find_dirty_eq(dmu_buf_impl_t * db,uint64_t txg)427 dbuf_find_dirty_eq(dmu_buf_impl_t *db, uint64_t txg)
428 {
429 dbuf_dirty_record_t *dr;
430
431 dr = dbuf_find_dirty_lte(db, txg);
432 if (dr && dr->dr_txg == txg)
433 return (dr);
434 return (NULL);
435 }
436
437 #define DBUF_GET_BUFC_TYPE(_db) \
438 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)
439
440 #define DBUF_IS_CACHEABLE(_db) \
441 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \
442 (dbuf_is_metadata(_db) && \
443 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))
444
445 #define DBUF_IS_L2CACHEABLE(_db) \
446 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \
447 (dbuf_is_metadata(_db) && \
448 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
449
450 #define DNODE_LEVEL_IS_L2CACHEABLE(_dn, _level) \
451 ((_dn)->dn_objset->os_secondary_cache == ZFS_CACHE_ALL || \
452 (((_level) > 0 || \
453 DMU_OT_IS_METADATA((_dn)->dn_handle->dnh_dnode->dn_type)) && \
454 ((_dn)->dn_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
455
456 #ifdef ZFS_DEBUG
457
458 /*
459 * There should be a ## between the string literal and fmt, to make it
460 * clear that we're joining two strings together, but gcc does not
461 * support that preprocessor token.
462 */
463 #define dprintf_dbuf(dbuf, fmt, ...) do { \
464 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
465 char __db_buf[32]; \
466 uint64_t __db_obj = (dbuf)->db.db_object; \
467 if (__db_obj == DMU_META_DNODE_OBJECT) \
468 (void) strcpy(__db_buf, "mdn"); \
469 else \
470 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
471 (u_longlong_t)__db_obj); \
472 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
473 "obj=%s lvl=%u blkid=%lld " fmt, \
474 __db_buf, (dbuf)->db_level, \
475 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
476 } \
477 _NOTE(CONSTCOND) } while (0)
478
479 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \
480 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
481 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \
482 snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \
483 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \
484 kmem_free(__blkbuf, BP_SPRINTF_LEN); \
485 } \
486 _NOTE(CONSTCOND) } while (0)
487
488 #define DBUF_VERIFY(db) dbuf_verify(db)
489
490 #else
491
492 #define dprintf_dbuf(db, fmt, ...)
493 #define dprintf_dbuf_bp(db, bp, fmt, ...)
494 #define DBUF_VERIFY(db)
495
496 #endif
497
498
499 #ifdef __cplusplus
500 }
501 #endif
502
503 #endif /* _SYS_DBUF_H */
504