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 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved. 25 */ 26 27 #ifndef _SYS_DBUF_H 28 #define _SYS_DBUF_H 29 30 #include <sys/dmu.h> 31 #include <sys/spa.h> 32 #include <sys/txg.h> 33 #include <sys/zio.h> 34 #include <sys/arc.h> 35 #include <sys/zfs_context.h> 36 #include <sys/refcount.h> 37 #include <sys/zrlock.h> 38 39 #ifdef __cplusplus 40 extern "C" { 41 #endif 42 43 #define IN_DMU_SYNC 2 44 45 /* 46 * define flags for dbuf_read 47 */ 48 49 #define DB_RF_MUST_SUCCEED (1 << 0) 50 #define DB_RF_CANFAIL (1 << 1) 51 #define DB_RF_HAVESTRUCT (1 << 2) 52 #define DB_RF_NOPREFETCH (1 << 3) 53 #define DB_RF_NEVERWAIT (1 << 4) 54 #define DB_RF_CACHED (1 << 5) 55 56 /* 57 * The simplified state transition diagram for dbufs looks like: 58 * 59 * +----> READ ----+ 60 * | | 61 * | V 62 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free) 63 * | ^ ^ 64 * | | | 65 * +----> FILL ----+ | 66 * | | 67 * | | 68 * +--------> NOFILL -------+ 69 */ 70 typedef enum dbuf_states { 71 DB_UNCACHED, 72 DB_FILL, 73 DB_NOFILL, 74 DB_READ, 75 DB_CACHED, 76 DB_EVICTING 77 } dbuf_states_t; 78 79 struct dnode; 80 struct dmu_tx; 81 82 /* 83 * level = 0 means the user data 84 * level = 1 means the single indirect block 85 * etc. 86 */ 87 88 struct dmu_buf_impl; 89 90 typedef enum override_states { 91 DR_NOT_OVERRIDDEN, 92 DR_IN_DMU_SYNC, 93 DR_OVERRIDDEN 94 } override_states_t; 95 96 typedef struct dbuf_dirty_record { 97 /* link on our parents dirty list */ 98 list_node_t dr_dirty_node; 99 100 /* transaction group this data will sync in */ 101 uint64_t dr_txg; 102 103 /* zio of outstanding write IO */ 104 zio_t *dr_zio; 105 106 /* pointer back to our dbuf */ 107 struct dmu_buf_impl *dr_dbuf; 108 109 /* pointer to next dirty record */ 110 struct dbuf_dirty_record *dr_next; 111 112 /* pointer to parent dirty record */ 113 struct dbuf_dirty_record *dr_parent; 114 115 union dirty_types { 116 struct dirty_indirect { 117 118 /* protect access to list */ 119 kmutex_t dr_mtx; 120 121 /* Our list of dirty children */ 122 list_t dr_children; 123 } di; 124 struct dirty_leaf { 125 126 /* 127 * dr_data is set when we dirty the buffer 128 * so that we can retain the pointer even if it 129 * gets COW'd in a subsequent transaction group. 130 */ 131 arc_buf_t *dr_data; 132 blkptr_t dr_overridden_by; 133 override_states_t dr_override_state; 134 uint8_t dr_copies; 135 boolean_t dr_nopwrite; 136 } dl; 137 } dt; 138 } dbuf_dirty_record_t; 139 140 typedef struct dmu_buf_impl { 141 /* 142 * The following members are immutable, with the exception of 143 * db.db_data, which is protected by db_mtx. 144 */ 145 146 /* the publicly visible structure */ 147 dmu_buf_t db; 148 149 /* the objset we belong to */ 150 struct objset *db_objset; 151 152 /* 153 * handle to safely access the dnode we belong to (NULL when evicted) 154 */ 155 struct dnode_handle *db_dnode_handle; 156 157 /* 158 * our parent buffer; if the dnode points to us directly, 159 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf 160 * only accessed by sync thread ??? 161 * (NULL when evicted) 162 * May change from NULL to non-NULL under the protection of db_mtx 163 * (see dbuf_check_blkptr()) 164 */ 165 struct dmu_buf_impl *db_parent; 166 167 /* 168 * link for hash table of all dmu_buf_impl_t's 169 */ 170 struct dmu_buf_impl *db_hash_next; 171 172 /* our block number */ 173 uint64_t db_blkid; 174 175 /* 176 * Pointer to the blkptr_t which points to us. May be NULL if we 177 * don't have one yet. (NULL when evicted) 178 */ 179 blkptr_t *db_blkptr; 180 181 /* 182 * Our indirection level. Data buffers have db_level==0. 183 * Indirect buffers which point to data buffers have 184 * db_level==1. etc. Buffers which contain dnodes have 185 * db_level==0, since the dnodes are stored in a file. 186 */ 187 uint8_t db_level; 188 189 /* db_mtx protects the members below */ 190 kmutex_t db_mtx; 191 192 /* 193 * Current state of the buffer 194 */ 195 dbuf_states_t db_state; 196 197 /* 198 * Refcount accessed by dmu_buf_{hold,rele}. 199 * If nonzero, the buffer can't be destroyed. 200 * Protected by db_mtx. 201 */ 202 refcount_t db_holds; 203 204 /* buffer holding our data */ 205 arc_buf_t *db_buf; 206 207 kcondvar_t db_changed; 208 dbuf_dirty_record_t *db_data_pending; 209 210 /* pointer to most recent dirty record for this buffer */ 211 dbuf_dirty_record_t *db_last_dirty; 212 213 /* 214 * Our link on the owner dnodes's dn_dbufs list. 215 * Protected by its dn_dbufs_mtx. 216 */ 217 list_node_t db_link; 218 219 /* Data which is unique to data (leaf) blocks: */ 220 221 /* stuff we store for the user (see dmu_buf_set_user) */ 222 void *db_user_ptr; 223 void **db_user_data_ptr_ptr; 224 dmu_buf_evict_func_t *db_evict_func; 225 226 uint8_t db_immediate_evict; 227 uint8_t db_freed_in_flight; 228 229 uint8_t db_dirtycnt; 230 } dmu_buf_impl_t; 231 232 /* Note: the dbuf hash table is exposed only for the mdb module */ 233 #define DBUF_MUTEXES 256 234 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)]) 235 typedef struct dbuf_hash_table { 236 uint64_t hash_table_mask; 237 dmu_buf_impl_t **hash_table; 238 kmutex_t hash_mutexes[DBUF_MUTEXES]; 239 } dbuf_hash_table_t; 240 241 242 uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset); 243 244 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data); 245 void dbuf_create_bonus(struct dnode *dn); 246 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx); 247 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag); 248 249 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx); 250 251 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag); 252 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid, 253 void *tag); 254 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create, 255 void *tag, dmu_buf_impl_t **dbp); 256 257 void dbuf_prefetch(struct dnode *dn, uint64_t blkid); 258 259 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag); 260 uint64_t dbuf_refcount(dmu_buf_impl_t *db); 261 262 void dbuf_rele(dmu_buf_impl_t *db, void *tag); 263 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag); 264 265 dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid); 266 267 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags); 268 void dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 269 void dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx); 270 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx); 271 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx); 272 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx); 273 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx); 274 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 275 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db); 276 277 void dbuf_clear(dmu_buf_impl_t *db); 278 void dbuf_evict(dmu_buf_impl_t *db); 279 280 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 281 void dbuf_unoverride(dbuf_dirty_record_t *dr); 282 void dbuf_sync_list(list_t *list, dmu_tx_t *tx); 283 void dbuf_release_bp(dmu_buf_impl_t *db); 284 285 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end, 286 struct dmu_tx *); 287 288 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx); 289 290 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode) 291 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock) 292 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db))) 293 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db))) 294 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db))) 295 #define DB_GET_SPA(_spa_p, _db) { \ 296 dnode_t *__dn; \ 297 DB_DNODE_ENTER(_db); \ 298 __dn = DB_DNODE(_db); \ 299 *(_spa_p) = __dn->dn_objset->os_spa; \ 300 DB_DNODE_EXIT(_db); \ 301 } 302 #define DB_GET_OBJSET(_os_p, _db) { \ 303 dnode_t *__dn; \ 304 DB_DNODE_ENTER(_db); \ 305 __dn = DB_DNODE(_db); \ 306 *(_os_p) = __dn->dn_objset; \ 307 DB_DNODE_EXIT(_db); \ 308 } 309 310 void dbuf_init(void); 311 void dbuf_fini(void); 312 313 boolean_t dbuf_is_metadata(dmu_buf_impl_t *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 #define DBUF_IS_L2COMPRESSIBLE(_db) \ 329 ((_db)->db_objset->os_compress != ZIO_COMPRESS_OFF) 330 331 #ifdef ZFS_DEBUG 332 333 /* 334 * There should be a ## between the string literal and fmt, to make it 335 * clear that we're joining two strings together, but gcc does not 336 * support that preprocessor token. 337 */ 338 #define dprintf_dbuf(dbuf, fmt, ...) do { \ 339 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 340 char __db_buf[32]; \ 341 uint64_t __db_obj = (dbuf)->db.db_object; \ 342 if (__db_obj == DMU_META_DNODE_OBJECT) \ 343 (void) strcpy(__db_buf, "mdn"); \ 344 else \ 345 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \ 346 (u_longlong_t)__db_obj); \ 347 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \ 348 "obj=%s lvl=%u blkid=%lld " fmt, \ 349 __db_buf, (dbuf)->db_level, \ 350 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \ 351 } \ 352 _NOTE(CONSTCOND) } while (0) 353 354 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \ 355 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 356 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \ 357 sprintf_blkptr(__blkbuf, bp); \ 358 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \ 359 kmem_free(__blkbuf, BP_SPRINTF_LEN); \ 360 } \ 361 _NOTE(CONSTCOND) } while (0) 362 363 #define DBUF_VERIFY(db) dbuf_verify(db) 364 365 #else 366 367 #define dprintf_dbuf(db, fmt, ...) 368 #define dprintf_dbuf_bp(db, bp, fmt, ...) 369 #define DBUF_VERIFY(db) 370 371 #endif 372 373 374 #ifdef __cplusplus 375 } 376 #endif 377 378 #endif /* _SYS_DBUF_H */ 379