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, 2018 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/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 58 /* 59 * The simplified state transition diagram for dbufs looks like: 60 * 61 * +----> READ ----+ 62 * | | 63 * | V 64 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free) 65 * | ^ ^ 66 * | | | 67 * +----> FILL ----+ | 68 * | | 69 * | | 70 * +--------> NOFILL -------+ 71 * 72 * DB_SEARCH is an invalid state for a dbuf. It is used by dbuf_free_range 73 * to find all dbufs in a range of a dnode and must be less than any other 74 * dbuf_states_t (see comment on dn_dbufs in dnode.h). 75 */ 76 typedef enum dbuf_states { 77 DB_SEARCH = -1, 78 DB_UNCACHED, 79 DB_FILL, 80 DB_NOFILL, 81 DB_READ, 82 DB_CACHED, 83 DB_EVICTING 84 } dbuf_states_t; 85 86 typedef enum dbuf_cached_state { 87 DB_NO_CACHE = -1, 88 DB_DBUF_CACHE, 89 DB_DBUF_METADATA_CACHE, 90 DB_CACHE_MAX 91 } dbuf_cached_state_t; 92 93 struct dnode; 94 struct dmu_tx; 95 96 /* 97 * level = 0 means the user data 98 * level = 1 means the single indirect block 99 * etc. 100 */ 101 102 struct dmu_buf_impl; 103 104 typedef enum override_states { 105 DR_NOT_OVERRIDDEN, 106 DR_IN_DMU_SYNC, 107 DR_OVERRIDDEN 108 } override_states_t; 109 110 typedef struct dbuf_dirty_record { 111 /* link on our parents dirty list */ 112 list_node_t dr_dirty_node; 113 114 /* transaction group this data will sync in */ 115 uint64_t dr_txg; 116 117 /* zio of outstanding write IO */ 118 zio_t *dr_zio; 119 120 /* pointer back to our dbuf */ 121 struct dmu_buf_impl *dr_dbuf; 122 123 /* pointer to next dirty record */ 124 struct dbuf_dirty_record *dr_next; 125 126 /* pointer to parent dirty record */ 127 struct dbuf_dirty_record *dr_parent; 128 129 /* How much space was changed to dsl_pool_dirty_space() for this? */ 130 unsigned int dr_accounted; 131 132 /* A copy of the bp that points to us */ 133 blkptr_t dr_bp_copy; 134 135 union dirty_types { 136 struct dirty_indirect { 137 138 /* protect access to list */ 139 kmutex_t dr_mtx; 140 141 /* Our list of dirty children */ 142 list_t dr_children; 143 } di; 144 struct dirty_leaf { 145 146 /* 147 * dr_data is set when we dirty the buffer 148 * so that we can retain the pointer even if it 149 * gets COW'd in a subsequent transaction group. 150 */ 151 arc_buf_t *dr_data; 152 blkptr_t dr_overridden_by; 153 override_states_t dr_override_state; 154 uint8_t dr_copies; 155 boolean_t dr_nopwrite; 156 } dl; 157 } dt; 158 } dbuf_dirty_record_t; 159 160 typedef struct dmu_buf_impl { 161 /* 162 * The following members are immutable, with the exception of 163 * db.db_data, which is protected by db_mtx. 164 */ 165 166 /* the publicly visible structure */ 167 dmu_buf_t db; 168 169 /* the objset we belong to */ 170 struct objset *db_objset; 171 172 /* 173 * handle to safely access the dnode we belong to (NULL when evicted) 174 */ 175 struct dnode_handle *db_dnode_handle; 176 177 /* 178 * our parent buffer; if the dnode points to us directly, 179 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf 180 * only accessed by sync thread ??? 181 * (NULL when evicted) 182 * May change from NULL to non-NULL under the protection of db_mtx 183 * (see dbuf_check_blkptr()) 184 */ 185 struct dmu_buf_impl *db_parent; 186 187 /* 188 * link for hash table of all dmu_buf_impl_t's 189 */ 190 struct dmu_buf_impl *db_hash_next; 191 192 /* our block number */ 193 uint64_t db_blkid; 194 195 /* 196 * Pointer to the blkptr_t which points to us. May be NULL if we 197 * don't have one yet. (NULL when evicted) 198 */ 199 blkptr_t *db_blkptr; 200 201 /* 202 * Our indirection level. Data buffers have db_level==0. 203 * Indirect buffers which point to data buffers have 204 * db_level==1. etc. Buffers which contain dnodes have 205 * db_level==0, since the dnodes are stored in a file. 206 */ 207 uint8_t db_level; 208 209 /* db_mtx protects the members below */ 210 kmutex_t db_mtx; 211 212 /* 213 * Current state of the buffer 214 */ 215 dbuf_states_t db_state; 216 217 /* 218 * Refcount accessed by dmu_buf_{hold,rele}. 219 * If nonzero, the buffer can't be destroyed. 220 * Protected by db_mtx. 221 */ 222 zfs_refcount_t db_holds; 223 224 /* buffer holding our data */ 225 arc_buf_t *db_buf; 226 227 kcondvar_t db_changed; 228 dbuf_dirty_record_t *db_data_pending; 229 230 /* pointer to most recent dirty record for this buffer */ 231 dbuf_dirty_record_t *db_last_dirty; 232 233 /* 234 * Our link on the owner dnodes's dn_dbufs list. 235 * Protected by its dn_dbufs_mtx. 236 */ 237 avl_node_t db_link; 238 239 /* Link in dbuf_cache or dbuf_metadata_cache */ 240 multilist_node_t db_cache_link; 241 242 /* Tells us which dbuf cache this dbuf is in, if any */ 243 dbuf_cached_state_t db_caching_status; 244 245 /* Data which is unique to data (leaf) blocks: */ 246 247 /* User callback information. */ 248 dmu_buf_user_t *db_user; 249 250 /* 251 * Evict user data as soon as the dirty and reference 252 * counts are equal. 253 */ 254 uint8_t db_user_immediate_evict; 255 256 /* 257 * This block was freed while a read or write was 258 * active. 259 */ 260 uint8_t db_freed_in_flight; 261 262 /* 263 * dnode_evict_dbufs() or dnode_evict_bonus() tried to 264 * evict this dbuf, but couldn't due to outstanding 265 * references. Evict once the refcount drops to 0. 266 */ 267 uint8_t db_pending_evict; 268 269 uint8_t db_dirtycnt; 270 } dmu_buf_impl_t; 271 272 /* Note: the dbuf hash table is exposed only for the mdb module */ 273 #define DBUF_MUTEXES 256 274 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)]) 275 typedef struct dbuf_hash_table { 276 uint64_t hash_table_mask; 277 dmu_buf_impl_t **hash_table; 278 kmutex_t hash_mutexes[DBUF_MUTEXES]; 279 } dbuf_hash_table_t; 280 281 uint64_t dbuf_whichblock(struct dnode *di, int64_t level, uint64_t offset); 282 283 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data); 284 void dbuf_create_bonus(struct dnode *dn); 285 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx); 286 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag); 287 288 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx); 289 290 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag); 291 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid, 292 void *tag); 293 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, 294 boolean_t fail_sparse, boolean_t fail_uncached, 295 void *tag, dmu_buf_impl_t **dbp); 296 297 void dbuf_prefetch(struct dnode *dn, int64_t level, uint64_t blkid, 298 zio_priority_t prio, arc_flags_t aflags); 299 300 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag); 301 boolean_t dbuf_try_add_ref(dmu_buf_t *db, objset_t *os, uint64_t obj, 302 uint64_t blkid, void *tag); 303 uint64_t dbuf_refcount(dmu_buf_impl_t *db); 304 305 void dbuf_rele(dmu_buf_impl_t *db, void *tag); 306 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag, boolean_t evicting); 307 308 dmu_buf_impl_t *dbuf_find(struct objset *os, uint64_t object, uint8_t level, 309 uint64_t blkid); 310 311 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags); 312 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx); 313 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx); 314 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx); 315 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx); 316 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 317 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db); 318 void dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data, 319 bp_embedded_type_t etype, enum zio_compress comp, 320 int uncompressed_size, int compressed_size, int byteorder, dmu_tx_t *tx); 321 322 void dbuf_destroy(dmu_buf_impl_t *db); 323 324 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 325 void dbuf_unoverride(dbuf_dirty_record_t *dr); 326 void dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx); 327 void dbuf_release_bp(dmu_buf_impl_t *db); 328 329 boolean_t dbuf_can_remap(const dmu_buf_impl_t *buf); 330 331 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end, 332 struct dmu_tx *); 333 334 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx); 335 336 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode) 337 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock) 338 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db))) 339 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db))) 340 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db))) 341 342 void dbuf_init(void); 343 void dbuf_fini(void); 344 345 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db); 346 347 #define DBUF_GET_BUFC_TYPE(_db) \ 348 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA) 349 350 #define DBUF_IS_CACHEABLE(_db) \ 351 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \ 352 (dbuf_is_metadata(_db) && \ 353 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA))) 354 355 #define DBUF_IS_L2CACHEABLE(_db) \ 356 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \ 357 (dbuf_is_metadata(_db) && \ 358 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA))) 359 360 #define DNODE_LEVEL_IS_L2CACHEABLE(_dn, _level) \ 361 ((_dn)->dn_objset->os_secondary_cache == ZFS_CACHE_ALL || \ 362 (((_level) > 0 || \ 363 DMU_OT_IS_METADATA((_dn)->dn_handle->dnh_dnode->dn_type)) && \ 364 ((_dn)->dn_objset->os_secondary_cache == ZFS_CACHE_METADATA))) 365 366 #ifdef ZFS_DEBUG 367 368 /* 369 * There should be a ## between the string literal and fmt, to make it 370 * clear that we're joining two strings together, but gcc does not 371 * support that preprocessor token. 372 */ 373 #define dprintf_dbuf(dbuf, fmt, ...) do { \ 374 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 375 char __db_buf[32]; \ 376 uint64_t __db_obj = (dbuf)->db.db_object; \ 377 if (__db_obj == DMU_META_DNODE_OBJECT) \ 378 (void) strcpy(__db_buf, "mdn"); \ 379 else \ 380 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \ 381 (u_longlong_t)__db_obj); \ 382 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \ 383 "obj=%s lvl=%u blkid=%lld " fmt, \ 384 __db_buf, (dbuf)->db_level, \ 385 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \ 386 } \ 387 _NOTE(CONSTCOND) } while (0) 388 389 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \ 390 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 391 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \ 392 snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \ 393 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \ 394 kmem_free(__blkbuf, BP_SPRINTF_LEN); \ 395 } \ 396 _NOTE(CONSTCOND) } while (0) 397 398 #define DBUF_VERIFY(db) dbuf_verify(db) 399 400 #else 401 402 #define dprintf_dbuf(db, fmt, ...) 403 #define dprintf_dbuf_bp(db, bp, fmt, ...) 404 #define DBUF_VERIFY(db) 405 406 #endif 407 408 409 #ifdef __cplusplus 410 } 411 #endif 412 413 #endif /* _SYS_DBUF_H */ 414