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