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, 2014 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 * DB_SEARCH is an invalid state for a dbuf. It is used by dbuf_free_range 71 * to find all dbufs in a range of a dnode and must be less than any other 72 * dbuf_states_t (see comment on dn_dbufs in dnode.h). 73 */ 74 typedef enum dbuf_states { 75 DB_SEARCH = -1, 76 DB_UNCACHED, 77 DB_FILL, 78 DB_NOFILL, 79 DB_READ, 80 DB_CACHED, 81 DB_EVICTING 82 } dbuf_states_t; 83 84 struct dnode; 85 struct dmu_tx; 86 87 /* 88 * level = 0 means the user data 89 * level = 1 means the single indirect block 90 * etc. 91 */ 92 93 struct dmu_buf_impl; 94 95 typedef enum override_states { 96 DR_NOT_OVERRIDDEN, 97 DR_IN_DMU_SYNC, 98 DR_OVERRIDDEN 99 } override_states_t; 100 101 typedef struct dbuf_dirty_record { 102 /* link on our parents dirty list */ 103 list_node_t dr_dirty_node; 104 105 /* transaction group this data will sync in */ 106 uint64_t dr_txg; 107 108 /* zio of outstanding write IO */ 109 zio_t *dr_zio; 110 111 /* pointer back to our dbuf */ 112 struct dmu_buf_impl *dr_dbuf; 113 114 /* pointer to next dirty record */ 115 struct dbuf_dirty_record *dr_next; 116 117 /* pointer to parent dirty record */ 118 struct dbuf_dirty_record *dr_parent; 119 120 /* How much space was changed to dsl_pool_dirty_space() for this? */ 121 unsigned int dr_accounted; 122 123 union dirty_types { 124 struct dirty_indirect { 125 126 /* protect access to list */ 127 kmutex_t dr_mtx; 128 129 /* Our list of dirty children */ 130 list_t dr_children; 131 } di; 132 struct dirty_leaf { 133 134 /* 135 * dr_data is set when we dirty the buffer 136 * so that we can retain the pointer even if it 137 * gets COW'd in a subsequent transaction group. 138 */ 139 arc_buf_t *dr_data; 140 blkptr_t dr_overridden_by; 141 override_states_t dr_override_state; 142 uint8_t dr_copies; 143 boolean_t dr_nopwrite; 144 } dl; 145 } dt; 146 } dbuf_dirty_record_t; 147 148 typedef struct dmu_buf_impl { 149 /* 150 * The following members are immutable, with the exception of 151 * db.db_data, which is protected by db_mtx. 152 */ 153 154 /* the publicly visible structure */ 155 dmu_buf_t db; 156 157 /* the objset we belong to */ 158 struct objset *db_objset; 159 160 /* 161 * handle to safely access the dnode we belong to (NULL when evicted) 162 */ 163 struct dnode_handle *db_dnode_handle; 164 165 /* 166 * our parent buffer; if the dnode points to us directly, 167 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf 168 * only accessed by sync thread ??? 169 * (NULL when evicted) 170 * May change from NULL to non-NULL under the protection of db_mtx 171 * (see dbuf_check_blkptr()) 172 */ 173 struct dmu_buf_impl *db_parent; 174 175 /* 176 * link for hash table of all dmu_buf_impl_t's 177 */ 178 struct dmu_buf_impl *db_hash_next; 179 180 /* our block number */ 181 uint64_t db_blkid; 182 183 /* 184 * Pointer to the blkptr_t which points to us. May be NULL if we 185 * don't have one yet. (NULL when evicted) 186 */ 187 blkptr_t *db_blkptr; 188 189 /* 190 * Our indirection level. Data buffers have db_level==0. 191 * Indirect buffers which point to data buffers have 192 * db_level==1. etc. Buffers which contain dnodes have 193 * db_level==0, since the dnodes are stored in a file. 194 */ 195 uint8_t db_level; 196 197 /* db_mtx protects the members below */ 198 kmutex_t db_mtx; 199 200 /* 201 * Current state of the buffer 202 */ 203 dbuf_states_t db_state; 204 205 /* 206 * Refcount accessed by dmu_buf_{hold,rele}. 207 * If nonzero, the buffer can't be destroyed. 208 * Protected by db_mtx. 209 */ 210 refcount_t db_holds; 211 212 /* buffer holding our data */ 213 arc_buf_t *db_buf; 214 215 kcondvar_t db_changed; 216 dbuf_dirty_record_t *db_data_pending; 217 218 /* pointer to most recent dirty record for this buffer */ 219 dbuf_dirty_record_t *db_last_dirty; 220 221 /* 222 * Our link on the owner dnodes's dn_dbufs list. 223 * Protected by its dn_dbufs_mtx. 224 */ 225 avl_node_t db_link; 226 227 /* Data which is unique to data (leaf) blocks: */ 228 229 /* stuff we store for the user (see dmu_buf_set_user) */ 230 void *db_user_ptr; 231 void **db_user_data_ptr_ptr; 232 dmu_buf_evict_func_t *db_evict_func; 233 234 uint8_t db_immediate_evict; 235 uint8_t db_freed_in_flight; 236 237 uint8_t db_dirtycnt; 238 } dmu_buf_impl_t; 239 240 /* Note: the dbuf hash table is exposed only for the mdb module */ 241 #define DBUF_MUTEXES 256 242 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)]) 243 typedef struct dbuf_hash_table { 244 uint64_t hash_table_mask; 245 dmu_buf_impl_t **hash_table; 246 kmutex_t hash_mutexes[DBUF_MUTEXES]; 247 } dbuf_hash_table_t; 248 249 250 uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset); 251 252 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data); 253 void dbuf_create_bonus(struct dnode *dn); 254 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx); 255 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag); 256 257 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx); 258 259 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag); 260 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid, 261 void *tag); 262 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create, 263 void *tag, dmu_buf_impl_t **dbp); 264 265 void dbuf_prefetch(struct dnode *dn, uint64_t blkid, zio_priority_t prio); 266 267 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag); 268 uint64_t dbuf_refcount(dmu_buf_impl_t *db); 269 270 void dbuf_rele(dmu_buf_impl_t *db, void *tag); 271 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag); 272 273 dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid); 274 275 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags); 276 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx); 277 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx); 278 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx); 279 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx); 280 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 281 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db); 282 void dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data, 283 bp_embedded_type_t etype, enum zio_compress comp, 284 int uncompressed_size, int compressed_size, int byteorder, dmu_tx_t *tx); 285 286 void dbuf_clear(dmu_buf_impl_t *db); 287 void dbuf_evict(dmu_buf_impl_t *db); 288 289 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 290 void dbuf_unoverride(dbuf_dirty_record_t *dr); 291 void dbuf_sync_list(list_t *list, dmu_tx_t *tx); 292 void dbuf_release_bp(dmu_buf_impl_t *db); 293 294 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end, 295 struct dmu_tx *); 296 297 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx); 298 299 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode) 300 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock) 301 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db))) 302 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db))) 303 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db))) 304 305 void dbuf_init(void); 306 void dbuf_fini(void); 307 308 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db); 309 310 #define DBUF_GET_BUFC_TYPE(_db) \ 311 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA) 312 313 #define DBUF_IS_CACHEABLE(_db) \ 314 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \ 315 (dbuf_is_metadata(_db) && \ 316 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA))) 317 318 #define DBUF_IS_L2CACHEABLE(_db) \ 319 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \ 320 (dbuf_is_metadata(_db) && \ 321 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA))) 322 323 #define DBUF_IS_L2COMPRESSIBLE(_db) \ 324 ((_db)->db_objset->os_compress != ZIO_COMPRESS_OFF || \ 325 (dbuf_is_metadata(_db) && zfs_mdcomp_disable == B_FALSE)) 326 327 #ifdef ZFS_DEBUG 328 329 /* 330 * There should be a ## between the string literal and fmt, to make it 331 * clear that we're joining two strings together, but gcc does not 332 * support that preprocessor token. 333 */ 334 #define dprintf_dbuf(dbuf, fmt, ...) do { \ 335 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 336 char __db_buf[32]; \ 337 uint64_t __db_obj = (dbuf)->db.db_object; \ 338 if (__db_obj == DMU_META_DNODE_OBJECT) \ 339 (void) strcpy(__db_buf, "mdn"); \ 340 else \ 341 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \ 342 (u_longlong_t)__db_obj); \ 343 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \ 344 "obj=%s lvl=%u blkid=%lld " fmt, \ 345 __db_buf, (dbuf)->db_level, \ 346 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \ 347 } \ 348 _NOTE(CONSTCOND) } while (0) 349 350 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \ 351 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 352 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \ 353 snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \ 354 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \ 355 kmem_free(__blkbuf, BP_SPRINTF_LEN); \ 356 } \ 357 _NOTE(CONSTCOND) } while (0) 358 359 #define DBUF_VERIFY(db) dbuf_verify(db) 360 361 #else 362 363 #define dprintf_dbuf(db, fmt, ...) 364 #define dprintf_dbuf_bp(db, bp, fmt, ...) 365 #define DBUF_VERIFY(db) 366 367 #endif 368 369 370 #ifdef __cplusplus 371 } 372 #endif 373 374 #endif /* _SYS_DBUF_H */ 375