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 2010 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 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 37 #ifdef __cplusplus 38 extern "C" { 39 #endif 40 41 #define DB_BONUS_BLKID (-1ULL) 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 #define LIST_LINK_INACTIVE(link) \ 88 ((link)->list_next == NULL && (link)->list_prev == NULL) 89 90 struct dmu_buf_impl; 91 92 typedef enum override_states { 93 DR_NOT_OVERRIDDEN, 94 DR_IN_DMU_SYNC, 95 DR_OVERRIDDEN 96 } override_states_t; 97 98 typedef struct dbuf_dirty_record { 99 /* link on our parents dirty list */ 100 list_node_t dr_dirty_node; 101 102 /* transaction group this data will sync in */ 103 uint64_t dr_txg; 104 105 /* zio of outstanding write IO */ 106 zio_t *dr_zio; 107 108 /* pointer back to our dbuf */ 109 struct dmu_buf_impl *dr_dbuf; 110 111 /* pointer to next dirty record */ 112 struct dbuf_dirty_record *dr_next; 113 114 /* pointer to parent dirty record */ 115 struct dbuf_dirty_record *dr_parent; 116 117 union dirty_types { 118 struct dirty_indirect { 119 120 /* protect access to list */ 121 kmutex_t dr_mtx; 122 123 /* Our list of dirty children */ 124 list_t dr_children; 125 } di; 126 struct dirty_leaf { 127 128 /* 129 * dr_data is set when we dirty the buffer 130 * so that we can retain the pointer even if it 131 * gets COW'd in a subsequent transaction group. 132 */ 133 arc_buf_t *dr_data; 134 blkptr_t dr_overridden_by; 135 override_states_t dr_override_state; 136 uint8_t dr_copies; 137 } dl; 138 } dt; 139 } dbuf_dirty_record_t; 140 141 typedef struct dmu_buf_impl { 142 /* 143 * The following members are immutable, with the exception of 144 * db.db_data, which is protected by db_mtx. 145 */ 146 147 /* the publicly visible structure */ 148 dmu_buf_t db; 149 150 /* the objset we belong to */ 151 struct objset *db_objset; 152 153 /* 154 * the dnode we belong to (NULL when evicted) 155 */ 156 struct dnode *db_dnode; 157 158 /* 159 * our parent buffer; if the dnode points to us directly, 160 * db_parent == db_dnode->dn_dbuf 161 * only accessed by sync thread ??? 162 * (NULL when evicted) 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); 245 246 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag); 247 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid, 248 void *tag); 249 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create, 250 void *tag, dmu_buf_impl_t **dbp); 251 252 void dbuf_prefetch(struct dnode *dn, uint64_t blkid); 253 254 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag); 255 uint64_t dbuf_refcount(dmu_buf_impl_t *db); 256 257 void dbuf_rele(dmu_buf_impl_t *db, void *tag); 258 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag); 259 260 dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid); 261 262 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags); 263 void dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 264 void dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx); 265 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx); 266 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx); 267 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx); 268 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx); 269 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 270 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db); 271 272 void dbuf_clear(dmu_buf_impl_t *db); 273 void dbuf_evict(dmu_buf_impl_t *db); 274 275 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 276 void dbuf_unoverride(dbuf_dirty_record_t *dr); 277 void dbuf_sync_list(list_t *list, dmu_tx_t *tx); 278 279 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end, 280 struct dmu_tx *); 281 282 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx); 283 284 void dbuf_init(void); 285 void dbuf_fini(void); 286 287 #define DBUF_IS_METADATA(db) \ 288 ((db)->db_level > 0 || dmu_ot[(db)->db_dnode->dn_type].ot_metadata) 289 290 #define DBUF_GET_BUFC_TYPE(db) \ 291 (DBUF_IS_METADATA(db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA) 292 293 #define DBUF_IS_CACHEABLE(db) \ 294 ((db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \ 295 (DBUF_IS_METADATA(db) && \ 296 ((db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA))) 297 298 #define DBUF_IS_L2CACHEABLE(db) \ 299 ((db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \ 300 (DBUF_IS_METADATA(db) && \ 301 ((db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA))) 302 303 #ifdef ZFS_DEBUG 304 305 /* 306 * There should be a ## between the string literal and fmt, to make it 307 * clear that we're joining two strings together, but gcc does not 308 * support that preprocessor token. 309 */ 310 #define dprintf_dbuf(dbuf, fmt, ...) do { \ 311 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 312 char __db_buf[32]; \ 313 uint64_t __db_obj = (dbuf)->db.db_object; \ 314 if (__db_obj == DMU_META_DNODE_OBJECT) \ 315 (void) strcpy(__db_buf, "mdn"); \ 316 else \ 317 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \ 318 (u_longlong_t)__db_obj); \ 319 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \ 320 "obj=%s lvl=%u blkid=%lld " fmt, \ 321 __db_buf, (dbuf)->db_level, \ 322 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \ 323 } \ 324 _NOTE(CONSTCOND) } while (0) 325 326 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \ 327 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 328 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \ 329 sprintf_blkptr(__blkbuf, bp); \ 330 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \ 331 kmem_free(__blkbuf, BP_SPRINTF_LEN); \ 332 } \ 333 _NOTE(CONSTCOND) } while (0) 334 335 #define DBUF_VERIFY(db) dbuf_verify(db) 336 337 #else 338 339 #define dprintf_dbuf(db, fmt, ...) 340 #define dprintf_dbuf_bp(db, bp, fmt, ...) 341 #define DBUF_VERIFY(db) 342 343 #endif 344 345 346 #ifdef __cplusplus 347 } 348 #endif 349 350 #endif /* _SYS_DBUF_H */ 351