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 * Copyright 2014 Nexenta Systems, Inc. All rights reserved. 26 */ 27 28 #ifndef _SYS_DBUF_H 29 #define _SYS_DBUF_H 30 31 #include <sys/dmu.h> 32 #include <sys/spa.h> 33 #include <sys/txg.h> 34 #include <sys/zio.h> 35 #include <sys/arc.h> 36 #include <sys/zfs_context.h> 37 #include <sys/refcount.h> 38 #include <sys/zrlock.h> 39 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 #define IN_DMU_SYNC 2 45 46 /* 47 * define flags for dbuf_read 48 */ 49 50 #define DB_RF_MUST_SUCCEED (1 << 0) 51 #define DB_RF_CANFAIL (1 << 1) 52 #define DB_RF_HAVESTRUCT (1 << 2) 53 #define DB_RF_NOPREFETCH (1 << 3) 54 #define DB_RF_NEVERWAIT (1 << 4) 55 #define DB_RF_CACHED (1 << 5) 56 57 #define DBUF_EVICT_ALL -1 58 59 /* 60 * The simplified state transition diagram for dbufs looks like: 61 * 62 * +----> READ ----+ 63 * | | 64 * | V 65 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free) 66 * | ^ ^ 67 * | | | 68 * +----> FILL ----+ | 69 * | | 70 * | | 71 * +--------> NOFILL -------+ 72 * 73 * DB_SEARCH is an invalid state for a dbuf. It is used by dbuf_free_range 74 * to find all dbufs in a range of a dnode and must be less than any other 75 * dbuf_states_t (see comment on dn_dbufs in dnode.h). 76 */ 77 typedef enum dbuf_states { 78 DB_SEARCH = -1, 79 DB_UNCACHED, 80 DB_FILL, 81 DB_NOFILL, 82 DB_READ, 83 DB_CACHED, 84 DB_EVICTING 85 } dbuf_states_t; 86 87 struct dnode; 88 struct dmu_tx; 89 90 /* 91 * level = 0 means the user data 92 * level = 1 means the single indirect block 93 * etc. 94 */ 95 96 struct dmu_buf_impl; 97 98 typedef enum override_states { 99 DR_NOT_OVERRIDDEN, 100 DR_IN_DMU_SYNC, 101 DR_OVERRIDDEN 102 } override_states_t; 103 104 typedef struct dbuf_dirty_record { 105 /* link on our parents dirty list */ 106 list_node_t dr_dirty_node; 107 108 /* transaction group this data will sync in */ 109 uint64_t dr_txg; 110 111 /* zio of outstanding write IO */ 112 zio_t *dr_zio; 113 114 /* pointer back to our dbuf */ 115 struct dmu_buf_impl *dr_dbuf; 116 117 /* pointer to next dirty record */ 118 struct dbuf_dirty_record *dr_next; 119 120 /* pointer to parent dirty record */ 121 struct dbuf_dirty_record *dr_parent; 122 123 /* How much space was changed to dsl_pool_dirty_space() for this? */ 124 unsigned int dr_accounted; 125 126 /* use special class of dirty entry */ 127 boolean_t dr_usesc; 128 129 union dirty_types { 130 struct dirty_indirect { 131 132 /* protect access to list */ 133 kmutex_t dr_mtx; 134 135 /* Our list of dirty children */ 136 list_t dr_children; 137 } di; 138 struct dirty_leaf { 139 140 /* 141 * dr_data is set when we dirty the buffer 142 * so that we can retain the pointer even if it 143 * gets COW'd in a subsequent transaction group. 144 */ 145 arc_buf_t *dr_data; 146 blkptr_t dr_overridden_by; 147 override_states_t dr_override_state; 148 uint8_t dr_copies; 149 boolean_t dr_nopwrite; 150 } dl; 151 } dt; 152 } dbuf_dirty_record_t; 153 154 typedef struct dmu_buf_impl { 155 /* 156 * The following members are immutable, with the exception of 157 * db.db_data, which is protected by db_mtx. 158 */ 159 160 /* the publicly visible structure */ 161 dmu_buf_t db; 162 163 /* the objset we belong to */ 164 struct objset *db_objset; 165 166 /* 167 * handle to safely access the dnode we belong to (NULL when evicted) 168 */ 169 struct dnode_handle *db_dnode_handle; 170 171 /* 172 * our parent buffer; if the dnode points to us directly, 173 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf 174 * only accessed by sync thread ??? 175 * (NULL when evicted) 176 * May change from NULL to non-NULL under the protection of db_mtx 177 * (see dbuf_check_blkptr()) 178 */ 179 struct dmu_buf_impl *db_parent; 180 181 /* our block number */ 182 uint64_t db_blkid; 183 184 /* 185 * Pointer to the blkptr_t which points to us. May be NULL if we 186 * don't have one yet. (NULL when evicted) 187 */ 188 blkptr_t *db_blkptr; 189 190 /* 191 * Our indirection level. Data buffers have db_level==0. 192 * Indirect buffers which point to data buffers have 193 * db_level==1. etc. Buffers which contain dnodes have 194 * db_level==0, since the dnodes are stored in a file. 195 */ 196 uint8_t db_level; 197 198 /* db_mtx protects the members below */ 199 kmutex_t db_mtx; 200 201 /* 202 * Current state of the buffer 203 */ 204 dbuf_states_t db_state; 205 206 /* 207 * Refcount accessed by dmu_buf_{hold,rele}. 208 * If nonzero, the buffer can't be destroyed. 209 * Protected by db_mtx. 210 */ 211 refcount_t db_holds; 212 213 /* buffer holding our data */ 214 arc_buf_t *db_buf; 215 216 kcondvar_t db_changed; 217 dbuf_dirty_record_t *db_data_pending; 218 219 /* pointer to most recent dirty record for this buffer */ 220 dbuf_dirty_record_t *db_last_dirty; 221 222 /* 223 * Our link on the owner dnodes's dn_dbufs list. 224 * Protected by its dn_dbufs_mtx. 225 */ 226 avl_node_t db_link; 227 228 /* Data which is unique to data (leaf) blocks: */ 229 230 /* stuff we store for the user (see dmu_buf_set_user) */ 231 void *db_user_ptr; 232 void **db_user_data_ptr_ptr; 233 dmu_buf_evict_func_t *db_evict_func; 234 235 uint8_t db_immediate_evict; 236 uint8_t db_freed_in_flight; 237 238 uint8_t db_dirtycnt; 239 } dmu_buf_impl_t; 240 241 /* Note: the dbuf hash table is exposed only for the mdb module */ 242 #define DBUF_MUTEXES 256 243 #define DBUF_LOCK_PAD 64 244 typedef struct { 245 kmutex_t mtx; 246 #ifdef _KERNEL 247 unsigned char pad[(DBUF_LOCK_PAD - sizeof (kmutex_t))]; 248 #endif 249 } dbuf_mutex_t; 250 #define DBUF_HASH_MUTEX(h, idx) \ 251 (&((h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)].mtx)) 252 typedef struct dbuf_hash_table { 253 uint64_t hash_table_mask; 254 dmu_buf_impl_t **hash_table; 255 dbuf_mutex_t hash_mutexes[DBUF_MUTEXES]; 256 } dbuf_hash_table_t; 257 258 259 uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset); 260 261 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data); 262 void dbuf_create_bonus(struct dnode *dn); 263 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx); 264 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag); 265 266 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx); 267 268 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag); 269 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid, 270 void *tag); 271 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create, 272 void *tag, dmu_buf_impl_t **dbp); 273 274 void dbuf_prefetch(struct dnode *dn, uint64_t blkid, zio_priority_t prio); 275 276 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag); 277 uint64_t dbuf_refcount(dmu_buf_impl_t *db); 278 279 void dbuf_rele(dmu_buf_impl_t *db, void *tag); 280 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag); 281 282 dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid); 283 284 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags); 285 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx); 286 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx); 287 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx); 288 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx); 289 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 290 dbuf_dirty_record_t *dbuf_dirty_sc(dmu_buf_impl_t *db, dmu_tx_t *tx, 291 boolean_t usesc); 292 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db); 293 void dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data, 294 bp_embedded_type_t etype, enum zio_compress comp, 295 int uncompressed_size, int compressed_size, int byteorder, dmu_tx_t *tx); 296 297 void dbuf_clear(dmu_buf_impl_t *db); 298 void dbuf_evict(dmu_buf_impl_t *db); 299 300 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx); 301 void dbuf_unoverride(dbuf_dirty_record_t *dr); 302 void dbuf_sync_list(list_t *list, dmu_tx_t *tx); 303 void dbuf_release_bp(dmu_buf_impl_t *db); 304 305 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end, 306 struct dmu_tx *); 307 308 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx); 309 310 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode) 311 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock) 312 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db))) 313 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db))) 314 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db))) 315 316 void dbuf_init(void); 317 void dbuf_fini(void); 318 319 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db); 320 boolean_t dbuf_ddt_is_l2cacheable(dmu_buf_impl_t *db); 321 boolean_t dbuf_meta_is_l2cacheable(dmu_buf_impl_t *db); 322 323 #define DBUF_GET_BUFC_TYPE(_db) \ 324 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA) 325 326 #define DBUF_IS_CACHEABLE(_db) \ 327 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \ 328 (dbuf_is_metadata(_db) && \ 329 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA))) 330 331 332 /* 333 * Checks whether we need to cache dbuf in l2arc. 334 * Metadata is l2cacheable if it is not placed on special device 335 * or it is placed on special device in "dual" mode. We need to check 336 * for ddt in ZFS_CACHE_ALL and ZFS_CACHE_METADATA because it is in MOS. 337 * ZFS_CACHE_DATA mode actually means to cache both data and cacheable 338 * metadata. 339 */ 340 #define DBUF_IS_L2CACHEABLE(_db) \ 341 (((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL && \ 342 (dbuf_ddt_is_l2cacheable(_db) == B_TRUE)) || \ 343 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA && \ 344 (dbuf_is_metadata(_db)) && \ 345 (dbuf_ddt_is_l2cacheable(_db) == B_TRUE)) || \ 346 ((dbuf_meta_is_l2cacheable(_db) == B_TRUE) && \ 347 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_DATA))) 348 349 #define DBUF_IS_L2COMPRESSIBLE(_db) \ 350 ((_db)->db_objset->os_compress != ZIO_COMPRESS_OFF || \ 351 (dbuf_is_metadata(_db) && zfs_mdcomp_disable == B_FALSE)) 352 353 #ifdef ZFS_DEBUG 354 355 /* 356 * There should be a ## between the string literal and fmt, to make it 357 * clear that we're joining two strings together, but gcc does not 358 * support that preprocessor token. 359 */ 360 #define dprintf_dbuf(dbuf, fmt, ...) do { \ 361 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 362 char __db_buf[32]; \ 363 uint64_t __db_obj = (dbuf)->db.db_object; \ 364 if (__db_obj == DMU_META_DNODE_OBJECT) \ 365 (void) strcpy(__db_buf, "mdn"); \ 366 else \ 367 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \ 368 (u_longlong_t)__db_obj); \ 369 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \ 370 "obj=%s lvl=%u blkid=%lld " fmt, \ 371 __db_buf, (dbuf)->db_level, \ 372 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \ 373 } \ 374 _NOTE(CONSTCOND) } while (0) 375 376 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \ 377 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \ 378 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \ 379 snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \ 380 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \ 381 kmem_free(__blkbuf, BP_SPRINTF_LEN); \ 382 } \ 383 _NOTE(CONSTCOND) } while (0) 384 385 #define DBUF_VERIFY(db) dbuf_verify(db) 386 387 #else 388 389 #define dprintf_dbuf(db, fmt, ...) 390 #define dprintf_dbuf_bp(db, bp, fmt, ...) 391 #define DBUF_VERIFY(db) 392 393 #endif 394 395 396 #ifdef __cplusplus 397 } 398 #endif 399 400 #endif /* _SYS_DBUF_H */