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 https://opensource.org/licenses/CDDL-1.0.
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 #define DB_RF_PARTIAL_FIRST (1 << 7)
59 #define DB_RF_PARTIAL_MORE (1 << 8)
60
61 /*
62 * The simplified state transition diagram for dbufs looks like:
63 *
64 * +-------> READ ------+
65 * | |
66 * | V
67 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free)
68 * ^ | ^ ^
69 * | | | |
70 * | +-------> FILL ------+ |
71 * | | | |
72 * | | | |
73 * | +------> NOFILL -----+-----> UNCACHED
74 * | | (Direct I/O)
75 * +---------------+
76 *
77 * DB_SEARCH is an invalid state for a dbuf. It is used by dbuf_free_range
78 * to find all dbufs in a range of a dnode and must be less than any other
79 * dbuf_states_t (see comment on dn_dbufs in dnode.h).
80 */
81 typedef enum dbuf_states {
82 DB_MARKER = -2,
83 DB_SEARCH = -1,
84 DB_UNCACHED,
85 DB_FILL,
86 DB_NOFILL,
87 DB_READ,
88 DB_CACHED,
89 DB_EVICTING
90 } dbuf_states_t;
91
92 typedef enum dbuf_cached_state {
93 DB_NO_CACHE = -1,
94 DB_DBUF_CACHE,
95 DB_DBUF_METADATA_CACHE,
96 DB_CACHE_MAX
97 } dbuf_cached_state_t;
98
99 struct dnode;
100 struct dmu_tx;
101
102 /*
103 * level = 0 means the user data
104 * level = 1 means the single indirect block
105 * etc.
106 */
107
108 struct dmu_buf_impl;
109
110 typedef enum override_states {
111 DR_NOT_OVERRIDDEN,
112 DR_IN_DMU_SYNC,
113 DR_OVERRIDDEN
114 } override_states_t;
115
116 typedef enum db_lock_type {
117 DLT_NONE,
118 DLT_PARENT,
119 DLT_OBJSET
120 } db_lock_type_t;
121
122 typedef struct dbuf_dirty_record {
123 /* link on our parents dirty list */
124 list_node_t dr_dirty_node;
125
126 /* transaction group this data will sync in */
127 uint64_t dr_txg;
128
129 /* zio of outstanding write IO */
130 zio_t *dr_zio;
131
132 /* pointer back to our dbuf */
133 struct dmu_buf_impl *dr_dbuf;
134
135 /* list link for dbuf dirty records */
136 list_node_t dr_dbuf_node;
137
138 /*
139 * The dnode we are part of. Note that the dnode can not be moved or
140 * evicted due to the hold that's added by dnode_setdirty() or
141 * dmu_objset_sync_dnodes(), and released by dnode_rele_task() or
142 * userquota_updates_task(). This hold is necessary for
143 * dirty_lightweight_leaf-type dirty records, which don't have a hold
144 * on a dbuf.
145 */
146 dnode_t *dr_dnode;
147
148 /* pointer to parent dirty record */
149 struct dbuf_dirty_record *dr_parent;
150
151 /* How much space was changed to dsl_pool_dirty_space() for this? */
152 unsigned int dr_accounted;
153
154 /* A copy of the bp that points to us */
155 blkptr_t dr_bp_copy;
156
157 union dirty_types {
158 struct dirty_indirect {
159
160 /* protect access to list */
161 kmutex_t dr_mtx;
162
163 /* Our list of dirty children */
164 list_t dr_children;
165 } di;
166 struct dirty_leaf {
167
168 /*
169 * dr_data is set when we dirty the buffer
170 * so that we can retain the pointer even if it
171 * gets COW'd in a subsequent transaction group.
172 */
173 arc_buf_t *dr_data;
174 override_states_t dr_override_state;
175 uint8_t dr_copies;
176 boolean_t dr_nopwrite;
177 boolean_t dr_brtwrite;
178 boolean_t dr_diowrite;
179 boolean_t dr_has_raw_params;
180
181 /* Override and raw params are mutually exclusive. */
182 union {
183 blkptr_t dr_overridden_by;
184 struct {
185 /*
186 * If dr_has_raw_params is set, the
187 * following crypt params will be set
188 * on the BP that's written.
189 */
190 boolean_t dr_byteorder;
191 uint8_t dr_salt[ZIO_DATA_SALT_LEN];
192 uint8_t dr_iv[ZIO_DATA_IV_LEN];
193 uint8_t dr_mac[ZIO_DATA_MAC_LEN];
194 };
195 };
196 } dl;
197 struct dirty_lightweight_leaf {
198 /*
199 * This dirty record refers to a leaf (level=0)
200 * block, whose dbuf has not been instantiated for
201 * performance reasons.
202 */
203 uint64_t dr_blkid;
204 abd_t *dr_abd;
205 zio_prop_t dr_props;
206 zio_flag_t dr_flags;
207 } dll;
208 } dt;
209 } dbuf_dirty_record_t;
210
211 typedef struct dmu_buf_impl {
212 /*
213 * The following members are immutable, with the exception of
214 * db.db_data, which is protected by db_mtx.
215 */
216
217 /* the publicly visible structure */
218 dmu_buf_t db;
219
220 /* the objset we belong to */
221 struct objset *db_objset;
222
223 /*
224 * Handle to safely access the dnode we belong to (NULL when evicted)
225 * if dnode_move() is used on the platform, or just dnode otherwise.
226 */
227 #if !defined(__linux__) && !defined(__FreeBSD__)
228 #define USE_DNODE_HANDLE 1
229 struct dnode_handle *db_dnode_handle;
230 #else
231 struct dnode *db_dnode;
232 #endif
233
234 /*
235 * our parent buffer; if the dnode points to us directly,
236 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf
237 * only accessed by sync thread ???
238 * (NULL when evicted)
239 * May change from NULL to non-NULL under the protection of db_mtx
240 * (see dbuf_check_blkptr())
241 */
242 struct dmu_buf_impl *db_parent;
243
244 /*
245 * link for hash table of all dmu_buf_impl_t's
246 */
247 struct dmu_buf_impl *db_hash_next;
248
249 /*
250 * Our link on the owner dnodes's dn_dbufs list.
251 * Protected by its dn_dbufs_mtx. Should be on the same cache line
252 * as db_level and db_blkid for the best avl_add() performance.
253 */
254 avl_node_t db_link;
255
256 /* our block number */
257 uint64_t db_blkid;
258
259 /*
260 * Pointer to the blkptr_t which points to us. May be NULL if we
261 * don't have one yet. (NULL when evicted)
262 */
263 blkptr_t *db_blkptr;
264
265 /*
266 * Our indirection level. Data buffers have db_level==0.
267 * Indirect buffers which point to data buffers have
268 * db_level==1. etc. Buffers which contain dnodes have
269 * db_level==0, since the dnodes are stored in a file.
270 */
271 uint8_t db_level;
272
273 /* This block was freed while a read or write was active. */
274 uint8_t db_freed_in_flight;
275
276 /*
277 * Evict user data as soon as the dirty and reference counts are equal.
278 */
279 uint8_t db_user_immediate_evict;
280
281 /*
282 * dnode_evict_dbufs() or dnode_evict_bonus() tried to evict this dbuf,
283 * but couldn't due to outstanding references. Evict once the refcount
284 * drops to 0.
285 */
286 uint8_t db_pending_evict;
287
288 /* Number of TXGs in which this buffer is dirty. */
289 uint8_t db_dirtycnt;
290
291 /* The buffer was partially read. More reads may follow. */
292 uint8_t db_partial_read;
293
294 /*
295 * Protects db_buf's contents if they contain an indirect block or data
296 * block of the meta-dnode. We use this lock to protect the structure of
297 * the block tree. This means that when modifying this dbuf's data, we
298 * grab its rwlock. When modifying its parent's data (including the
299 * blkptr to this dbuf), we grab the parent's rwlock. The lock ordering
300 * for this lock is:
301 * 1) dn_struct_rwlock
302 * 2) db_rwlock
303 * We don't currently grab multiple dbufs' db_rwlocks at once.
304 */
305 krwlock_t db_rwlock;
306
307 /* buffer holding our data */
308 arc_buf_t *db_buf;
309
310 /* db_mtx protects the members below */
311 kmutex_t db_mtx;
312
313 /*
314 * Current state of the buffer
315 */
316 dbuf_states_t db_state;
317
318 /* In which dbuf cache this dbuf is, if any. */
319 dbuf_cached_state_t db_caching_status;
320
321 /*
322 * Refcount accessed by dmu_buf_{hold,rele}.
323 * If nonzero, the buffer can't be destroyed.
324 * Protected by db_mtx.
325 */
326 zfs_refcount_t db_holds;
327
328 kcondvar_t db_changed;
329 dbuf_dirty_record_t *db_data_pending;
330
331 /* List of dirty records for the buffer sorted newest to oldest. */
332 list_t db_dirty_records;
333
334 /* Link in dbuf_cache or dbuf_metadata_cache */
335 multilist_node_t db_cache_link;
336
337 uint64_t db_hash;
338
339 /* User callback information. */
340 dmu_buf_user_t *db_user;
341 } dmu_buf_impl_t;
342
343 #define DBUF_HASH_MUTEX(h, idx) \
344 (&(h)->hash_mutexes[(idx) & ((h)->hash_mutex_mask)])
345
346 typedef struct dbuf_hash_table {
347 uint64_t hash_table_mask;
348 uint64_t hash_mutex_mask;
349 dmu_buf_impl_t **hash_table;
350 kmutex_t *hash_mutexes;
351 } dbuf_hash_table_t;
352
353 typedef void (*dbuf_prefetch_fn)(void *, uint64_t, uint64_t, boolean_t);
354
355 extern kmem_cache_t *dbuf_dirty_kmem_cache;
356
357 uint64_t dbuf_whichblock(const struct dnode *di, const int64_t level,
358 const uint64_t offset);
359
360 void dbuf_create_bonus(struct dnode *dn);
361 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx);
362
363 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx);
364
365 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, const void *tag);
366 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid,
367 const void *tag);
368 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid,
369 boolean_t fail_sparse, boolean_t fail_uncached,
370 const void *tag, dmu_buf_impl_t **dbp);
371
372 int dbuf_prefetch_impl(struct dnode *dn, int64_t level, uint64_t blkid,
373 zio_priority_t prio, arc_flags_t aflags, dbuf_prefetch_fn cb,
374 void *arg);
375 int dbuf_prefetch(struct dnode *dn, int64_t level, uint64_t blkid,
376 zio_priority_t prio, arc_flags_t aflags);
377
378 void dbuf_add_ref(dmu_buf_impl_t *db, const void *tag);
379 boolean_t dbuf_try_add_ref(dmu_buf_t *db, objset_t *os, uint64_t obj,
380 uint64_t blkid, const void *tag);
381 uint64_t dbuf_refcount(dmu_buf_impl_t *db);
382
383 void dbuf_rele(dmu_buf_impl_t *db, const void *tag);
384 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, const void *tag,
385 boolean_t evicting);
386
387 dmu_buf_impl_t *dbuf_find(struct objset *os, uint64_t object, uint8_t level,
388 uint64_t blkid, uint64_t *hash_out);
389
390 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags);
391 void dmu_buf_will_clone_or_dio(dmu_buf_t *db, dmu_tx_t *tx);
392 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
393 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx, boolean_t canfail);
394 boolean_t dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx, boolean_t failed);
395 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx);
396 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
397 dbuf_dirty_record_t *dbuf_dirty_lightweight(dnode_t *dn, uint64_t blkid,
398 dmu_tx_t *tx);
399 boolean_t dbuf_undirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
400 int dmu_buf_get_bp_from_dbuf(dmu_buf_impl_t *db, blkptr_t **bp);
401 int dmu_buf_untransform_direct(dmu_buf_impl_t *db, spa_t *spa);
402 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db);
403 void dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data,
404 bp_embedded_type_t etype, enum zio_compress comp,
405 int uncompressed_size, int compressed_size, int byteorder, dmu_tx_t *tx);
406
407 int dmu_lightweight_write_by_dnode(dnode_t *dn, uint64_t offset, abd_t *abd,
408 const struct zio_prop *zp, zio_flag_t flags, dmu_tx_t *tx);
409
410 void dmu_buf_redact(dmu_buf_t *dbuf, dmu_tx_t *tx);
411 void dbuf_destroy(dmu_buf_impl_t *db);
412
413 void dbuf_unoverride(dbuf_dirty_record_t *dr);
414 void dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx);
415 void dbuf_release_bp(dmu_buf_impl_t *db);
416 db_lock_type_t dmu_buf_lock_parent(dmu_buf_impl_t *db, krw_t rw,
417 const void *tag);
418 void dmu_buf_unlock_parent(dmu_buf_impl_t *db, db_lock_type_t type,
419 const void *tag);
420
421 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end,
422 struct dmu_tx *);
423
424 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx);
425
426 void dbuf_stats_init(dbuf_hash_table_t *hash);
427 void dbuf_stats_destroy(void);
428
429 int dbuf_dnode_findbp(dnode_t *dn, uint64_t level, uint64_t blkid,
430 blkptr_t *bp, uint16_t *datablkszsec, uint8_t *indblkshift);
431
432 #ifdef USE_DNODE_HANDLE
433 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode)
434 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock)
435 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db)))
436 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db)))
437 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db)))
438 #else
439 #define DB_DNODE(_db) ((_db)->db_dnode)
440 #define DB_DNODE_LOCK(_db)
441 #define DB_DNODE_ENTER(_db)
442 #define DB_DNODE_EXIT(_db)
443 #define DB_DNODE_HELD(_db) (B_TRUE)
444 #endif
445
446 void dbuf_init(void);
447 void dbuf_fini(void);
448
449 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db);
450
451 static inline dbuf_dirty_record_t *
dbuf_find_dirty_lte(dmu_buf_impl_t * db,uint64_t txg)452 dbuf_find_dirty_lte(dmu_buf_impl_t *db, uint64_t txg)
453 {
454 dbuf_dirty_record_t *dr;
455
456 for (dr = list_head(&db->db_dirty_records);
457 dr != NULL && dr->dr_txg > txg;
458 dr = list_next(&db->db_dirty_records, dr))
459 continue;
460 return (dr);
461 }
462
463 static inline dbuf_dirty_record_t *
dbuf_find_dirty_eq(dmu_buf_impl_t * db,uint64_t txg)464 dbuf_find_dirty_eq(dmu_buf_impl_t *db, uint64_t txg)
465 {
466 dbuf_dirty_record_t *dr;
467
468 dr = dbuf_find_dirty_lte(db, txg);
469 if (dr && dr->dr_txg == txg)
470 return (dr);
471 return (NULL);
472 }
473
474 #define DBUF_GET_BUFC_TYPE(_db) \
475 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)
476
477 #define DBUF_IS_CACHEABLE(_db) \
478 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \
479 (dbuf_is_metadata(_db) && \
480 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))
481
482 boolean_t dbuf_is_l2cacheable(dmu_buf_impl_t *db, blkptr_t *db_bp);
483
484 #ifdef ZFS_DEBUG
485
486 /*
487 * There should be a ## between the string literal and fmt, to make it
488 * clear that we're joining two strings together, but gcc does not
489 * support that preprocessor token.
490 */
491 #define dprintf_dbuf(dbuf, fmt, ...) do { \
492 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
493 char __db_buf[32]; \
494 uint64_t __db_obj = (dbuf)->db.db_object; \
495 if (__db_obj == DMU_META_DNODE_OBJECT) \
496 (void) strlcpy(__db_buf, "mdn", sizeof (__db_buf)); \
497 else \
498 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
499 (u_longlong_t)__db_obj); \
500 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
501 "obj=%s lvl=%u blkid=%lld " fmt, \
502 __db_buf, (dbuf)->db_level, \
503 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
504 } \
505 } while (0)
506
507 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \
508 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
509 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \
510 snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \
511 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \
512 kmem_free(__blkbuf, BP_SPRINTF_LEN); \
513 } \
514 } while (0)
515
516 #define DBUF_VERIFY(db) dbuf_verify(db)
517
518 #else
519
520 #define dprintf_dbuf(db, fmt, ...)
521 #define dprintf_dbuf_bp(db, bp, fmt, ...)
522 #define DBUF_VERIFY(db)
523
524 #endif
525
526
527 #ifdef __cplusplus
528 }
529 #endif
530
531 #endif /* _SYS_DBUF_H */
532