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.
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.
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]
22 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23 * Copyright (c) 2013 by Saso Kiselkov. All rights reserved.
34 #include <sys/zfs_context.h>
35 #include <sys/refcount.h>
36 #include <sys/zrlock.h>
45 * define flags for dbuf_read
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)
56 * The simplified state transition diagram for dbufs looks like:
61 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free)
67 * +--------> NOFILL -------+
69 typedef enum dbuf_states {
82 * level = 0 means the user data
83 * level = 1 means the single indirect block
89 typedef enum override_states {
95 typedef struct dbuf_dirty_record {
96 /* link on our parents dirty list */
97 list_node_t dr_dirty_node;
99 /* transaction group this data will sync in */
102 /* zio of outstanding write IO */
105 /* pointer back to our dbuf */
106 struct dmu_buf_impl *dr_dbuf;
108 /* pointer to next dirty record */
109 struct dbuf_dirty_record *dr_next;
111 /* pointer to parent dirty record */
112 struct dbuf_dirty_record *dr_parent;
115 struct dirty_indirect {
117 /* protect access to list */
120 /* Our list of dirty children */
126 * dr_data is set when we dirty the buffer
127 * so that we can retain the pointer even if it
128 * gets COW'd in a subsequent transaction group.
131 blkptr_t dr_overridden_by;
132 override_states_t dr_override_state;
136 } dbuf_dirty_record_t;
138 typedef struct dmu_buf_impl {
140 * The following members are immutable, with the exception of
141 * db.db_data, which is protected by db_mtx.
144 /* the publicly visible structure */
147 /* the objset we belong to */
148 struct objset *db_objset;
151 * handle to safely access the dnode we belong to (NULL when evicted)
153 struct dnode_handle *db_dnode_handle;
156 * our parent buffer; if the dnode points to us directly,
157 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf
158 * only accessed by sync thread ???
159 * (NULL when evicted)
160 * May change from NULL to non-NULL under the protection of db_mtx
161 * (see dbuf_check_blkptr())
163 struct dmu_buf_impl *db_parent;
166 * link for hash table of all dmu_buf_impl_t's
168 struct dmu_buf_impl *db_hash_next;
170 /* our block number */
174 * Pointer to the blkptr_t which points to us. May be NULL if we
175 * don't have one yet. (NULL when evicted)
180 * Our indirection level. Data buffers have db_level==0.
181 * Indirect buffers which point to data buffers have
182 * db_level==1. etc. Buffers which contain dnodes have
183 * db_level==0, since the dnodes are stored in a file.
187 /* db_mtx protects the members below */
191 * Current state of the buffer
193 dbuf_states_t db_state;
196 * Refcount accessed by dmu_buf_{hold,rele}.
197 * If nonzero, the buffer can't be destroyed.
198 * Protected by db_mtx.
202 /* buffer holding our data */
205 kcondvar_t db_changed;
206 dbuf_dirty_record_t *db_data_pending;
208 /* pointer to most recent dirty record for this buffer */
209 dbuf_dirty_record_t *db_last_dirty;
212 * Our link on the owner dnodes's dn_dbufs list.
213 * Protected by its dn_dbufs_mtx.
217 /* Data which is unique to data (leaf) blocks: */
219 /* stuff we store for the user (see dmu_buf_set_user) */
221 void **db_user_data_ptr_ptr;
222 dmu_buf_evict_func_t *db_evict_func;
224 uint8_t db_immediate_evict;
225 uint8_t db_freed_in_flight;
230 /* Note: the dbuf hash table is exposed only for the mdb module */
231 #define DBUF_MUTEXES 256
232 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)])
233 typedef struct dbuf_hash_table {
234 uint64_t hash_table_mask;
235 dmu_buf_impl_t **hash_table;
236 kmutex_t hash_mutexes[DBUF_MUTEXES];
240 uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset);
242 void dbuf_create_bonus(struct dnode *dn);
243 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx);
245 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx);
247 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag);
248 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid,
250 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create,
251 void *tag, dmu_buf_impl_t **dbp);
253 void dbuf_prefetch(struct dnode *dn, uint64_t blkid);
255 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag);
256 uint64_t dbuf_refcount(dmu_buf_impl_t *db);
258 void dbuf_rele(dmu_buf_impl_t *db, void *tag);
259 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag);
261 dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid);
263 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags);
264 void dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
265 void dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx);
266 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
267 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx);
268 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx);
269 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx);
270 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
271 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db);
273 void dbuf_clear(dmu_buf_impl_t *db);
274 void dbuf_evict(dmu_buf_impl_t *db);
276 void dbuf_unoverride(dbuf_dirty_record_t *dr);
277 void dbuf_sync_list(list_t *list, dmu_tx_t *tx);
278 void dbuf_release_bp(dmu_buf_impl_t *db);
280 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end,
283 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx);
285 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode)
286 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock)
287 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db)))
288 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db)))
289 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db)))
290 #define DB_GET_SPA(_spa_p, _db) { \
292 DB_DNODE_ENTER(_db); \
293 __dn = DB_DNODE(_db); \
294 *(_spa_p) = __dn->dn_objset->os_spa; \
295 DB_DNODE_EXIT(_db); \
297 #define DB_GET_OBJSET(_os_p, _db) { \
299 DB_DNODE_ENTER(_db); \
300 __dn = DB_DNODE(_db); \
301 *(_os_p) = __dn->dn_objset; \
302 DB_DNODE_EXIT(_db); \
305 void dbuf_init(void);
306 void dbuf_fini(void);
308 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db);
310 #define DBUF_IS_METADATA(_db) \
311 (dbuf_is_metadata(_db))
313 #define DBUF_GET_BUFC_TYPE(_db) \
314 (DBUF_IS_METADATA(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)
316 #define DBUF_IS_CACHEABLE(_db) \
317 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \
318 (DBUF_IS_METADATA(_db) && \
319 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))
321 #define DBUF_IS_L2CACHEABLE(_db) \
322 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \
323 (DBUF_IS_METADATA(_db) && \
324 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
326 #define DBUF_IS_L2COMPRESSIBLE(_db) \
327 ((_db)->db_objset->os_compress != ZIO_COMPRESS_OFF)
332 * There should be a ## between the string literal and fmt, to make it
333 * clear that we're joining two strings together, but gcc does not
334 * support that preprocessor token.
336 #define dprintf_dbuf(dbuf, fmt, ...) do { \
337 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
339 uint64_t __db_obj = (dbuf)->db.db_object; \
340 if (__db_obj == DMU_META_DNODE_OBJECT) \
341 (void) strcpy(__db_buf, "mdn"); \
343 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
344 (u_longlong_t)__db_obj); \
345 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
346 "obj=%s lvl=%u blkid=%lld " fmt, \
347 __db_buf, (dbuf)->db_level, \
348 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
350 _NOTE(CONSTCOND) } while (0)
352 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \
353 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
354 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_PUSHPAGE); \
355 sprintf_blkptr(__blkbuf, bp); \
356 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \
357 kmem_free(__blkbuf, BP_SPRINTF_LEN); \
359 _NOTE(CONSTCOND) } while (0)
361 #define DBUF_VERIFY(db) dbuf_verify(db)
365 #define dprintf_dbuf(db, fmt, ...)
366 #define dprintf_dbuf_bp(db, bp, fmt, ...)
367 #define DBUF_VERIFY(db)
376 #endif /* _SYS_DBUF_H */