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) 2013 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 /* How much space was changed to dsl_pool_dirty_space() for this? */ 116 unsigned int dr_accounted; 117 118 union dirty_types { 119 struct dirty_indirect { 120 121 /* protect access to list */ 122 kmutex_t dr_mtx; 123 124 /* Our list of dirty children */ 125 list_t dr_children; 126 } di; 127 struct dirty_leaf { 128 129 /* 130 * dr_data is set when we dirty the buffer 131 * so that we can retain the pointer even if it 132 * gets COW'd in a subsequent transaction group. 133 */ 134 arc_buf_t *dr_data; 135 blkptr_t dr_overridden_by; 136 override_states_t dr_override_state; 137 uint8_t dr_copies; 138 boolean_t dr_nopwrite; 139 } dl; 140 } dt; 141 } dbuf_dirty_record_t; 142 143 typedef struct dmu_buf_impl { 144 /* 145 * The following members are immutable, with the exception of 146 * db.db_data, which is protected by db_mtx. 147 */ 148 149 /* the publicly visible structure */ 150 dmu_buf_t db; 151 152 /* the objset we belong to */ 153 struct objset *db_objset; 154 155 /* 156 * handle to safely access the dnode we belong to (NULL when evicted) 157 */ 158 struct dnode_handle *db_dnode_handle; 159 160 /* 161 * our parent buffer; if the dnode points to us directly, 162 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf 163 * only accessed by sync thread ??? 164 * (NULL when evicted) 165 * May change from NULL to non-NULL under the protection of db_mtx 166 * (see dbuf_check_blkptr()) 167 */ 168 struct dmu_buf_impl *db_parent; 169 170 /* 171 * link for hash table of all dmu_buf_impl_t's 172 */ 173 struct dmu_buf_impl *db_hash_next; 174 175 /* our block number */ 176 uint64_t db_blkid; 177 178 /* 179 * Pointer to the blkptr_t which points to us. May be NULL if we 180 * don't have one yet. (NULL when evicted) 181 */ 182 blkptr_t *db_blkptr; 183 184 /* 185 * Our indirection level. Data buffers have db_level==0. 186 * Indirect buffers which point to data buffers have 187 * db_level==1. etc. Buffers which contain dnodes have 188 * db_level==0, since the dnodes are stored in a file. 189 */ 190 uint8_t db_level; 191 192 /* db_mtx protects the members below */ 193 kmutex_t db_mtx; 194 195 /* 196 * Current state of the buffer 197 */ 198 dbuf_states_t db_state; 199 200 /* 201 * Refcount accessed by dmu_buf_{hold,rele}. 202 * If nonzero, the buffer can't be destroyed. 203 * Protected by db_mtx. 204 */ 205 refcount_t db_holds; 206 207 /* buffer holding our data */ 208 arc_buf_t *db_buf; 209 210 kcondvar_t db_changed; 211 dbuf_dirty_record_t *db_data_pending; 212 213 /* pointer to most recent dirty record for this buffer */ 214 dbuf_dirty_record_t *db_last_dirty; 215 216 /* 217 * Our link on the owner dnodes's dn_dbufs list. 218 * Protected by its dn_dbufs_mtx. 219 */ 220 list_node_t db_link; 221 222 /* Data which is unique to data (leaf) blocks: */ 223 224 /* stuff we store for the user (see dmu_buf_set_user) */ 225 void *db_user_ptr; 226 void **db_user_data_ptr_ptr; 227 dmu_buf_evict_func_t *db_evict_func; 228 229 uint8_t db_immediate_evict; 230 uint8_t db_freed_in_flight; 231 232 uint8_t db_dirtycnt; 233 } dmu_buf_impl_t; 234 235 /* Note: the dbuf hash table is exposed only for the mdb module */ 236 #define DBUF_MUTEXES 256 237 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)]) 238 typedef struct dbuf_hash_table { 239 uint64_t hash_table_mask; 240 dmu_buf_impl_t **hash_table; 241 kmutex_t hash_mutexes[DBUF_MUTEXES]; 242 } dbuf_hash_table_t; 243 244 245 uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset); 246 247 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data); 248 void dbuf_create_bonus(struct dnode *dn); 249 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx); 250 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag); 251 252 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx); 253 254 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag); 255 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid, 256 void *tag); 257 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create, 258 void *tag, dmu_buf_impl_t **dbp); 259 260 void dbuf_prefetch(struct dnode *dn, uint64_t blkid, zio_priority_t prio); 261 262 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag); 263 uint64_t dbuf_refcount(dmu_buf_impl_t *db); 264 265 void dbuf_rele(dmu_buf_impl_t *db, void *tag); 266 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag); 267 268 dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid); 269 270 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags); 271 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx); 272 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx); 273 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx); 274 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx); 275 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 276 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db); 277 278 void dbuf_clear(dmu_buf_impl_t *db); 279 void dbuf_evict(dmu_buf_impl_t *db); 280 281 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 282 void dbuf_unoverride(dbuf_dirty_record_t *dr); 283 void dbuf_sync_list(list_t *list, dmu_tx_t *tx); 284 void dbuf_release_bp(dmu_buf_impl_t *db); 285 286 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end, 287 struct dmu_tx *); 288 289 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx); 290 291 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode) 292 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock) 293 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db))) 294 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db))) 295 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db))) 296 297 void dbuf_init(void); 298 void dbuf_fini(void); 299 300 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db); 301 302 #define DBUF_GET_BUFC_TYPE(_db) \ 303 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA) 304 305 #define DBUF_IS_CACHEABLE(_db) \ 306 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \ 307 (dbuf_is_metadata(_db) && \ 308 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA))) 309 310 #define DBUF_IS_L2CACHEABLE(_db) \ 311 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \ 312 (dbuf_is_metadata(_db) && \ 313 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA))) 314 315 #define DBUF_IS_L2COMPRESSIBLE(_db) \ 316 ((_db)->db_objset->os_compress != ZIO_COMPRESS_OFF || \ 317 (dbuf_is_metadata(_db) && zfs_mdcomp_disable == B_FALSE)) 318 319 #ifdef ZFS_DEBUG 320 321 /* 322 * There should be a ## between the string literal and fmt, to make it 323 * clear that we're joining two strings together, but gcc does not 324 * support that preprocessor token. 325 */ 326 #define dprintf_dbuf(dbuf, fmt, ...) do { \ 327 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 328 char __db_buf[32]; \ 329 uint64_t __db_obj = (dbuf)->db.db_object; \ 330 if (__db_obj == DMU_META_DNODE_OBJECT) \ 331 (void) strcpy(__db_buf, "mdn"); \ 332 else \ 333 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \ 334 (u_longlong_t)__db_obj); \ 335 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \ 336 "obj=%s lvl=%u blkid=%lld " fmt, \ 337 __db_buf, (dbuf)->db_level, \ 338 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \ 339 } \ 340 _NOTE(CONSTCOND) } while (0) 341 342 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \ 343 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 344 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \ 345 snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \ 346 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \ 347 kmem_free(__blkbuf, BP_SPRINTF_LEN); \ 348 } \ 349 _NOTE(CONSTCOND) } while (0) 350 351 #define DBUF_VERIFY(db) dbuf_verify(db) 352 353 #else 354 355 #define dprintf_dbuf(db, fmt, ...) 356 #define dprintf_dbuf_bp(db, bp, fmt, ...) 357 #define DBUF_VERIFY(db) 358 359 #endif 360 361 362 #ifdef __cplusplus 363 } 364 #endif 365 366 #endif /* _SYS_DBUF_H */ 367