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.
33 #include <sys/zfs_context.h>
34 #include <sys/refcount.h>
43 * define flags for dbuf_read
46 #define DB_RF_MUST_SUCCEED (1 << 0)
47 #define DB_RF_CANFAIL (1 << 1)
48 #define DB_RF_HAVESTRUCT (1 << 2)
49 #define DB_RF_NOPREFETCH (1 << 3)
50 #define DB_RF_NEVERWAIT (1 << 4)
51 #define DB_RF_CACHED (1 << 5)
54 * The simplified state transition diagram for dbufs looks like:
59 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free)
65 * +--------> NOFILL -------+
67 typedef enum dbuf_states {
80 * level = 0 means the user data
81 * level = 1 means the single indirect block
85 #define LIST_LINK_INACTIVE(link) \
86 ((link)->list_next == NULL && (link)->list_prev == NULL)
90 typedef enum override_states {
96 typedef struct dbuf_dirty_record {
97 /* link on our parents dirty list */
98 list_node_t dr_dirty_node;
100 /* transaction group this data will sync in */
103 /* zio of outstanding write IO */
106 /* pointer back to our dbuf */
107 struct dmu_buf_impl *dr_dbuf;
109 /* pointer to next dirty record */
110 struct dbuf_dirty_record *dr_next;
112 /* pointer to parent dirty record */
113 struct dbuf_dirty_record *dr_parent;
116 struct dirty_indirect {
118 /* protect access to list */
121 /* Our list of dirty children */
127 * dr_data is set when we dirty the buffer
128 * so that we can retain the pointer even if it
129 * gets COW'd in a subsequent transaction group.
132 blkptr_t dr_overridden_by;
133 override_states_t dr_override_state;
137 } dbuf_dirty_record_t;
139 typedef struct dmu_buf_impl {
141 * The following members are immutable, with the exception of
142 * db.db_data, which is protected by db_mtx.
145 /* the publicly visible structure */
148 /* the objset we belong to */
149 struct objset *db_objset;
152 * the dnode we belong to (NULL when evicted)
154 struct dnode *db_dnode;
157 * our parent buffer; if the dnode points to us directly,
158 * db_parent == db_dnode->dn_dbuf
159 * only accessed by sync thread ???
160 * (NULL when evicted)
162 struct dmu_buf_impl *db_parent;
165 * link for hash table of all dmu_buf_impl_t's
167 struct dmu_buf_impl *db_hash_next;
169 /* our block number */
173 * Pointer to the blkptr_t which points to us. May be NULL if we
174 * don't have one yet. (NULL when evicted)
179 * Our indirection level. Data buffers have db_level==0.
180 * Indirect buffers which point to data buffers have
181 * db_level==1. etc. Buffers which contain dnodes have
182 * db_level==0, since the dnodes are stored in a file.
186 /* db_mtx protects the members below */
190 * Current state of the buffer
192 dbuf_states_t db_state;
195 * Refcount accessed by dmu_buf_{hold,rele}.
196 * If nonzero, the buffer can't be destroyed.
197 * Protected by db_mtx.
201 /* buffer holding our data */
204 kcondvar_t db_changed;
205 dbuf_dirty_record_t *db_data_pending;
207 /* pointer to most recent dirty record for this buffer */
208 dbuf_dirty_record_t *db_last_dirty;
211 * Our link on the owner dnodes's dn_dbufs list.
212 * Protected by its dn_dbufs_mtx.
216 /* Data which is unique to data (leaf) blocks: */
218 /* stuff we store for the user (see dmu_buf_set_user) */
220 void **db_user_data_ptr_ptr;
221 dmu_buf_evict_func_t *db_evict_func;
223 uint8_t db_immediate_evict;
224 uint8_t db_freed_in_flight;
229 /* Note: the dbuf hash table is exposed only for the mdb module */
230 #define DBUF_MUTEXES 256
231 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)])
232 typedef struct dbuf_hash_table {
233 uint64_t hash_table_mask;
234 dmu_buf_impl_t **hash_table;
235 kmutex_t hash_mutexes[DBUF_MUTEXES];
239 uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset);
241 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data);
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);
244 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag);
246 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx);
248 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag);
249 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid,
251 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create,
252 void *tag, dmu_buf_impl_t **dbp);
254 void dbuf_prefetch(struct dnode *dn, uint64_t blkid);
256 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag);
257 uint64_t dbuf_refcount(dmu_buf_impl_t *db);
259 void dbuf_rele(dmu_buf_impl_t *db, void *tag);
260 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag);
262 dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid);
264 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags);
265 void dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
266 void dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx);
267 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
268 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx);
269 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx);
270 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx);
271 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
272 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db);
274 void dbuf_clear(dmu_buf_impl_t *db);
275 void dbuf_evict(dmu_buf_impl_t *db);
277 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
278 void dbuf_unoverride(dbuf_dirty_record_t *dr);
279 void dbuf_sync_list(list_t *list, dmu_tx_t *tx);
280 void dbuf_release_bp(dmu_buf_impl_t *db);
282 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end,
285 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx);
287 void dbuf_init(void);
288 void dbuf_fini(void);
290 #define DBUF_IS_METADATA(db) \
291 ((db)->db_level > 0 || dmu_ot[(db)->db_dnode->dn_type].ot_metadata)
293 #define DBUF_GET_BUFC_TYPE(db) \
294 (DBUF_IS_METADATA(db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)
296 #define DBUF_IS_CACHEABLE(db) \
297 ((db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \
298 (DBUF_IS_METADATA(db) && \
299 ((db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))
301 #define DBUF_IS_L2CACHEABLE(db) \
302 ((db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \
303 (DBUF_IS_METADATA(db) && \
304 ((db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
309 * There should be a ## between the string literal and fmt, to make it
310 * clear that we're joining two strings together, but gcc does not
311 * support that preprocessor token.
313 #define dprintf_dbuf(dbuf, fmt, ...) do { \
314 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
316 uint64_t __db_obj = (dbuf)->db.db_object; \
317 if (__db_obj == DMU_META_DNODE_OBJECT) \
318 (void) strcpy(__db_buf, "mdn"); \
320 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
321 (u_longlong_t)__db_obj); \
322 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
323 "obj=%s lvl=%u blkid=%lld " fmt, \
324 __db_buf, (dbuf)->db_level, \
325 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
327 _NOTE(CONSTCOND) } while (0)
329 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \
330 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
331 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \
332 sprintf_blkptr(__blkbuf, bp); \
333 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \
334 kmem_free(__blkbuf, BP_SPRINTF_LEN); \
336 _NOTE(CONSTCOND) } while (0)
338 #define DBUF_VERIFY(db) dbuf_verify(db)
342 #define dprintf_dbuf(db, fmt, ...)
343 #define dprintf_dbuf_bp(db, bp, fmt, ...)
344 #define DBUF_VERIFY(db)
353 #endif /* _SYS_DBUF_H */