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 by Delphix. All rights reserved. 24 */ 25 26 #ifndef _SYS_DBUF_H 27 #define _SYS_DBUF_H 28 29 #include <sys/dmu.h> 30 #include <sys/spa.h> 31 #include <sys/txg.h> 32 #include <sys/zio.h> 33 #include <sys/arc.h> 34 #include <sys/zfs_context.h> 35 #include <sys/refcount.h> 36 #include <sys/zrlock.h> 37 38 #ifdef __cplusplus 39 extern "C" { 40 #endif 41 42 #define IN_DMU_SYNC 2 43 44 /* 45 * define flags for dbuf_read 46 */ 47 48 #define DB_RF_MUST_SUCCEED (1 << 0) 49 #define DB_RF_CANFAIL (1 << 1) 50 #define DB_RF_HAVESTRUCT (1 << 2) 51 #define DB_RF_NOPREFETCH (1 << 3) 52 #define DB_RF_NEVERWAIT (1 << 4) 53 #define DB_RF_CACHED (1 << 5) 54 55 /* 56 * The simplified state transition diagram for dbufs looks like: 57 * 58 * +----> READ ----+ 59 * | | 60 * | V 61 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free) 62 * | ^ ^ 63 * | | | 64 * +----> FILL ----+ | 65 * | | 66 * | | 67 * +--------> NOFILL -------+ 68 */ 69 typedef enum dbuf_states { 70 DB_UNCACHED, 71 DB_FILL, 72 DB_NOFILL, 73 DB_READ, 74 DB_CACHED, 75 DB_EVICTING 76 } dbuf_states_t; 77 78 struct dnode; 79 struct dmu_tx; 80 81 /* 82 * level = 0 means the user data 83 * level = 1 means the single indirect block 84 * etc. 85 */ 86 87 struct dmu_buf_impl; 88 89 typedef enum override_states { 90 DR_NOT_OVERRIDDEN, 91 DR_IN_DMU_SYNC, 92 DR_OVERRIDDEN 93 } override_states_t; 94 95 typedef struct dbuf_dirty_record { 96 /* link on our parents dirty list */ 97 list_node_t dr_dirty_node; 98 99 /* transaction group this data will sync in */ 100 uint64_t dr_txg; 101 102 /* zio of outstanding write IO */ 103 zio_t *dr_zio; 104 105 /* pointer back to our dbuf */ 106 struct dmu_buf_impl *dr_dbuf; 107 108 /* pointer to next dirty record */ 109 struct dbuf_dirty_record *dr_next; 110 111 /* pointer to parent dirty record */ 112 struct dbuf_dirty_record *dr_parent; 113 114 union dirty_types { 115 struct dirty_indirect { 116 117 /* protect access to list */ 118 kmutex_t dr_mtx; 119 120 /* Our list of dirty children */ 121 list_t dr_children; 122 } di; 123 struct dirty_leaf { 124 125 /* 126 * dr_data is set when we dirty the buffer 127 * so that we can retain the pointer even if it 128 * gets COW'd in a subsequent transaction group. 129 */ 130 arc_buf_t *dr_data; 131 blkptr_t dr_overridden_by; 132 override_states_t dr_override_state; 133 uint8_t dr_copies; 134 boolean_t dr_nopwrite; 135 } dl; 136 } dt; 137 } dbuf_dirty_record_t; 138 139 typedef struct dmu_buf_impl { 140 /* 141 * The following members are immutable, with the exception of 142 * db.db_data, which is protected by db_mtx. 143 */ 144 145 /* the publicly visible structure */ 146 dmu_buf_t db; 147 148 /* the objset we belong to */ 149 struct objset *db_objset; 150 151 /* 152 * handle to safely access the dnode we belong to (NULL when evicted) 153 */ 154 struct dnode_handle *db_dnode_handle; 155 156 /* 157 * our parent buffer; if the dnode points to us directly, 158 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf 159 * only accessed by sync thread ??? 160 * (NULL when evicted) 161 * May change from NULL to non-NULL under the protection of db_mtx 162 * (see dbuf_check_blkptr()) 163 */ 164 struct dmu_buf_impl *db_parent; 165 166 /* 167 * link for hash table of all dmu_buf_impl_t's 168 */ 169 struct dmu_buf_impl *db_hash_next; 170 171 /* our block number */ 172 uint64_t db_blkid; 173 174 /* 175 * Pointer to the blkptr_t which points to us. May be NULL if we 176 * don't have one yet. (NULL when evicted) 177 */ 178 blkptr_t *db_blkptr; 179 180 /* 181 * Our indirection level. Data buffers have db_level==0. 182 * Indirect buffers which point to data buffers have 183 * db_level==1. etc. Buffers which contain dnodes have 184 * db_level==0, since the dnodes are stored in a file. 185 */ 186 uint8_t db_level; 187 188 /* db_mtx protects the members below */ 189 kmutex_t db_mtx; 190 191 /* 192 * Current state of the buffer 193 */ 194 dbuf_states_t db_state; 195 196 /* 197 * Refcount accessed by dmu_buf_{hold,rele}. 198 * If nonzero, the buffer can't be destroyed. 199 * Protected by db_mtx. 200 */ 201 refcount_t db_holds; 202 203 /* buffer holding our data */ 204 arc_buf_t *db_buf; 205 206 kcondvar_t db_changed; 207 dbuf_dirty_record_t *db_data_pending; 208 209 /* pointer to most recent dirty record for this buffer */ 210 dbuf_dirty_record_t *db_last_dirty; 211 212 /* 213 * Our link on the owner dnodes's dn_dbufs list. 214 * Protected by its dn_dbufs_mtx. 215 */ 216 list_node_t db_link; 217 218 /* Data which is unique to data (leaf) blocks: */ 219 220 /* stuff we store for the user (see dmu_buf_set_user) */ 221 void *db_user_ptr; 222 void **db_user_data_ptr_ptr; 223 dmu_buf_evict_func_t *db_evict_func; 224 225 uint8_t db_immediate_evict; 226 uint8_t db_freed_in_flight; 227 228 uint8_t db_dirtycnt; 229 } dmu_buf_impl_t; 230 231 /* Note: the dbuf hash table is exposed only for the mdb module */ 232 #define DBUF_MUTEXES 256 233 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)]) 234 typedef struct dbuf_hash_table { 235 uint64_t hash_table_mask; 236 dmu_buf_impl_t **hash_table; 237 kmutex_t hash_mutexes[DBUF_MUTEXES]; 238 } dbuf_hash_table_t; 239 240 241 uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset); 242 243 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data); 244 void dbuf_create_bonus(struct dnode *dn); 245 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx); 246 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag); 247 248 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx); 249 250 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag); 251 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid, 252 void *tag); 253 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create, 254 void *tag, dmu_buf_impl_t **dbp); 255 256 void dbuf_prefetch(struct dnode *dn, uint64_t blkid); 257 258 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag); 259 uint64_t dbuf_refcount(dmu_buf_impl_t *db); 260 261 void dbuf_rele(dmu_buf_impl_t *db, void *tag); 262 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag); 263 264 dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid); 265 266 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags); 267 void dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 268 void dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx); 269 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx); 270 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx); 271 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx); 272 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx); 273 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 274 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db); 275 276 void dbuf_clear(dmu_buf_impl_t *db); 277 void dbuf_evict(dmu_buf_impl_t *db); 278 279 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 280 void dbuf_unoverride(dbuf_dirty_record_t *dr); 281 void dbuf_sync_list(list_t *list, dmu_tx_t *tx); 282 void dbuf_release_bp(dmu_buf_impl_t *db); 283 284 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end, 285 struct dmu_tx *); 286 287 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx); 288 289 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode) 290 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock) 291 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db))) 292 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db))) 293 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db))) 294 #define DB_GET_SPA(_spa_p, _db) { \ 295 dnode_t *__dn; \ 296 DB_DNODE_ENTER(_db); \ 297 __dn = DB_DNODE(_db); \ 298 *(_spa_p) = __dn->dn_objset->os_spa; \ 299 DB_DNODE_EXIT(_db); \ 300 } 301 #define DB_GET_OBJSET(_os_p, _db) { \ 302 dnode_t *__dn; \ 303 DB_DNODE_ENTER(_db); \ 304 __dn = DB_DNODE(_db); \ 305 *(_os_p) = __dn->dn_objset; \ 306 DB_DNODE_EXIT(_db); \ 307 } 308 309 void dbuf_init(void); 310 void dbuf_fini(void); 311 312 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db); 313 314 #define DBUF_IS_METADATA(_db) \ 315 (dbuf_is_metadata(_db)) 316 317 #define DBUF_GET_BUFC_TYPE(_db) \ 318 (DBUF_IS_METADATA(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA) 319 320 #define DBUF_IS_CACHEABLE(_db) \ 321 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \ 322 (DBUF_IS_METADATA(_db) && \ 323 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA))) 324 325 #define DBUF_IS_L2CACHEABLE(_db) \ 326 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \ 327 (DBUF_IS_METADATA(_db) && \ 328 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA))) 329 330 #ifdef ZFS_DEBUG 331 332 /* 333 * There should be a ## between the string literal and fmt, to make it 334 * clear that we're joining two strings together, but gcc does not 335 * support that preprocessor token. 336 */ 337 #define dprintf_dbuf(dbuf, fmt, ...) do { \ 338 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 339 char __db_buf[32]; \ 340 uint64_t __db_obj = (dbuf)->db.db_object; \ 341 if (__db_obj == DMU_META_DNODE_OBJECT) \ 342 (void) strcpy(__db_buf, "mdn"); \ 343 else \ 344 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \ 345 (u_longlong_t)__db_obj); \ 346 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \ 347 "obj=%s lvl=%u blkid=%lld " fmt, \ 348 __db_buf, (dbuf)->db_level, \ 349 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \ 350 } \ 351 _NOTE(CONSTCOND) } while (0) 352 353 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \ 354 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 355 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \ 356 sprintf_blkptr(__blkbuf, bp); \ 357 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \ 358 kmem_free(__blkbuf, BP_SPRINTF_LEN); \ 359 } \ 360 _NOTE(CONSTCOND) } while (0) 361 362 #define DBUF_VERIFY(db) dbuf_verify(db) 363 364 #else 365 366 #define dprintf_dbuf(db, fmt, ...) 367 #define dprintf_dbuf_bp(db, bp, fmt, ...) 368 #define DBUF_VERIFY(db) 369 370 #endif 371 372 373 #ifdef __cplusplus 374 } 375 #endif 376 377 #endif /* _SYS_DBUF_H */ 378