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, 2015 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 struct dnode; 87 struct dmu_tx; 88 89 /* 90 * level = 0 means the user data 91 * level = 1 means the single indirect block 92 * etc. 93 */ 94 95 struct dmu_buf_impl; 96 97 typedef enum override_states { 98 DR_NOT_OVERRIDDEN, 99 DR_IN_DMU_SYNC, 100 DR_OVERRIDDEN 101 } override_states_t; 102 103 typedef struct dbuf_dirty_record { 104 /* link on our parents dirty list */ 105 list_node_t dr_dirty_node; 106 107 /* transaction group this data will sync in */ 108 uint64_t dr_txg; 109 110 /* zio of outstanding write IO */ 111 zio_t *dr_zio; 112 113 /* pointer back to our dbuf */ 114 struct dmu_buf_impl *dr_dbuf; 115 116 /* pointer to next dirty record */ 117 struct dbuf_dirty_record *dr_next; 118 119 /* pointer to parent dirty record */ 120 struct dbuf_dirty_record *dr_parent; 121 122 /* How much space was changed to dsl_pool_dirty_space() for this? */ 123 unsigned int dr_accounted; 124 125 /* A copy of the bp that points to us */ 126 blkptr_t dr_bp_copy; 127 128 union dirty_types { 129 struct dirty_indirect { 130 131 /* protect access to list */ 132 kmutex_t dr_mtx; 133 134 /* Our list of dirty children */ 135 list_t dr_children; 136 } di; 137 struct dirty_leaf { 138 139 /* 140 * dr_data is set when we dirty the buffer 141 * so that we can retain the pointer even if it 142 * gets COW'd in a subsequent transaction group. 143 */ 144 arc_buf_t *dr_data; 145 blkptr_t dr_overridden_by; 146 override_states_t dr_override_state; 147 uint8_t dr_copies; 148 boolean_t dr_nopwrite; 149 } dl; 150 } dt; 151 } dbuf_dirty_record_t; 152 153 typedef struct dmu_buf_impl { 154 /* 155 * The following members are immutable, with the exception of 156 * db.db_data, which is protected by db_mtx. 157 */ 158 159 /* the publicly visible structure */ 160 dmu_buf_t db; 161 162 /* the objset we belong to */ 163 struct objset *db_objset; 164 165 /* 166 * handle to safely access the dnode we belong to (NULL when evicted) 167 */ 168 struct dnode_handle *db_dnode_handle; 169 170 /* 171 * our parent buffer; if the dnode points to us directly, 172 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf 173 * only accessed by sync thread ??? 174 * (NULL when evicted) 175 * May change from NULL to non-NULL under the protection of db_mtx 176 * (see dbuf_check_blkptr()) 177 */ 178 struct dmu_buf_impl *db_parent; 179 180 /* 181 * link for hash table of all dmu_buf_impl_t's 182 */ 183 struct dmu_buf_impl *db_hash_next; 184 185 /* our block number */ 186 uint64_t db_blkid; 187 188 /* 189 * Pointer to the blkptr_t which points to us. May be NULL if we 190 * don't have one yet. (NULL when evicted) 191 */ 192 blkptr_t *db_blkptr; 193 194 /* 195 * Our indirection level. Data buffers have db_level==0. 196 * Indirect buffers which point to data buffers have 197 * db_level==1. etc. Buffers which contain dnodes have 198 * db_level==0, since the dnodes are stored in a file. 199 */ 200 uint8_t db_level; 201 202 /* db_mtx protects the members below */ 203 kmutex_t db_mtx; 204 205 /* 206 * Current state of the buffer 207 */ 208 dbuf_states_t db_state; 209 210 /* 211 * Refcount accessed by dmu_buf_{hold,rele}. 212 * If nonzero, the buffer can't be destroyed. 213 * Protected by db_mtx. 214 */ 215 refcount_t db_holds; 216 217 /* buffer holding our data */ 218 arc_buf_t *db_buf; 219 220 kcondvar_t db_changed; 221 dbuf_dirty_record_t *db_data_pending; 222 223 /* pointer to most recent dirty record for this buffer */ 224 dbuf_dirty_record_t *db_last_dirty; 225 226 /* 227 * Our link on the owner dnodes's dn_dbufs list. 228 * Protected by its dn_dbufs_mtx. 229 */ 230 avl_node_t db_link; 231 232 /* 233 * Link in dbuf_cache. 234 */ 235 multilist_node_t db_cache_link; 236 237 /* Data which is unique to data (leaf) blocks: */ 238 239 /* User callback information. */ 240 dmu_buf_user_t *db_user; 241 242 /* 243 * Evict user data as soon as the dirty and reference 244 * counts are equal. 245 */ 246 uint8_t db_user_immediate_evict; 247 248 /* 249 * This block was freed while a read or write was 250 * active. 251 */ 252 uint8_t db_freed_in_flight; 253 254 /* 255 * dnode_evict_dbufs() or dnode_evict_bonus() tried to 256 * evict this dbuf, but couldn't due to outstanding 257 * references. Evict once the refcount drops to 0. 258 */ 259 uint8_t db_pending_evict; 260 261 uint8_t db_dirtycnt; 262 } dmu_buf_impl_t; 263 264 /* Note: the dbuf hash table is exposed only for the mdb module */ 265 #define DBUF_MUTEXES 256 266 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)]) 267 typedef struct dbuf_hash_table { 268 uint64_t hash_table_mask; 269 dmu_buf_impl_t **hash_table; 270 kmutex_t hash_mutexes[DBUF_MUTEXES]; 271 } dbuf_hash_table_t; 272 273 uint64_t dbuf_whichblock(struct dnode *di, int64_t level, uint64_t offset); 274 275 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data); 276 void dbuf_create_bonus(struct dnode *dn); 277 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx); 278 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag); 279 280 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx); 281 282 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag); 283 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid, 284 void *tag); 285 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, 286 boolean_t fail_sparse, boolean_t fail_uncached, 287 void *tag, dmu_buf_impl_t **dbp); 288 289 void dbuf_prefetch(struct dnode *dn, int64_t level, uint64_t blkid, 290 zio_priority_t prio, arc_flags_t aflags); 291 292 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag); 293 boolean_t dbuf_try_add_ref(dmu_buf_t *db, objset_t *os, uint64_t obj, 294 uint64_t blkid, void *tag); 295 uint64_t dbuf_refcount(dmu_buf_impl_t *db); 296 297 void dbuf_rele(dmu_buf_impl_t *db, void *tag); 298 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag); 299 300 dmu_buf_impl_t *dbuf_find(struct objset *os, uint64_t object, uint8_t level, 301 uint64_t blkid); 302 303 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags); 304 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx); 305 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx); 306 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx); 307 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx); 308 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 309 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db); 310 void dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data, 311 bp_embedded_type_t etype, enum zio_compress comp, 312 int uncompressed_size, int compressed_size, int byteorder, dmu_tx_t *tx); 313 314 void dbuf_destroy(dmu_buf_impl_t *db); 315 316 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 317 void dbuf_unoverride(dbuf_dirty_record_t *dr); 318 void dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx); 319 void dbuf_release_bp(dmu_buf_impl_t *db); 320 321 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end, 322 struct dmu_tx *); 323 324 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx); 325 326 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode) 327 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock) 328 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db))) 329 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db))) 330 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db))) 331 332 void dbuf_init(void); 333 void dbuf_fini(void); 334 335 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db); 336 337 #define DBUF_GET_BUFC_TYPE(_db) \ 338 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA) 339 340 #define DBUF_IS_CACHEABLE(_db) \ 341 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \ 342 (dbuf_is_metadata(_db) && \ 343 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA))) 344 345 #define DBUF_IS_L2CACHEABLE(_db) \ 346 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \ 347 (dbuf_is_metadata(_db) && \ 348 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA))) 349 350 #define DNODE_LEVEL_IS_L2CACHEABLE(_dn, _level) \ 351 ((_dn)->dn_objset->os_secondary_cache == ZFS_CACHE_ALL || \ 352 (((_level) > 0 || \ 353 DMU_OT_IS_METADATA((_dn)->dn_handle->dnh_dnode->dn_type)) && \ 354 ((_dn)->dn_objset->os_secondary_cache == ZFS_CACHE_METADATA))) 355 356 #ifdef ZFS_DEBUG 357 358 /* 359 * There should be a ## between the string literal and fmt, to make it 360 * clear that we're joining two strings together, but gcc does not 361 * support that preprocessor token. 362 */ 363 #define dprintf_dbuf(dbuf, fmt, ...) do { \ 364 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 365 char __db_buf[32]; \ 366 uint64_t __db_obj = (dbuf)->db.db_object; \ 367 if (__db_obj == DMU_META_DNODE_OBJECT) \ 368 (void) strcpy(__db_buf, "mdn"); \ 369 else \ 370 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \ 371 (u_longlong_t)__db_obj); \ 372 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \ 373 "obj=%s lvl=%u blkid=%lld " fmt, \ 374 __db_buf, (dbuf)->db_level, \ 375 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \ 376 } \ 377 _NOTE(CONSTCOND) } while (0) 378 379 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \ 380 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 381 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \ 382 snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \ 383 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \ 384 kmem_free(__blkbuf, BP_SPRINTF_LEN); \ 385 } \ 386 _NOTE(CONSTCOND) } while (0) 387 388 #define DBUF_VERIFY(db) dbuf_verify(db) 389 390 #else 391 392 #define dprintf_dbuf(db, fmt, ...) 393 #define dprintf_dbuf_bp(db, bp, fmt, ...) 394 #define DBUF_VERIFY(db) 395 396 #endif 397 398 399 #ifdef __cplusplus 400 } 401 #endif 402 403 #endif /* _SYS_DBUF_H */ 404