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 by Delphix. All rights reserved.
24 */
25
26 #ifndef _SYS_DBUF_H
27 #define _SYS_DBUF_H
28
29 #include <sys/dmu.h>
30 #include <sys/spa.h>
31 #include <sys/txg.h>
32 #include <sys/zio.h>
33 #include <sys/arc.h>
34 #include <sys/zfs_context.h>
35 #include <sys/refcount.h>
36 #include <sys/zrlock.h>
37
38 #ifdef __cplusplus
39 extern "C" {
40 #endif
41
42 #define IN_DMU_SYNC 2
43
44 /*
45 * define flags for dbuf_read
46 */
47
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)
54
55 /*
56 * The simplified state transition diagram for dbufs looks like:
57 *
58 * +----> READ ----+
59 * | |
60 * | V
61 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free)
62 * | ^ ^
63 * | | |
64 * +----> FILL ----+ |
65 * | |
66 * | |
67 * +--------> NOFILL -------+
68 */
69 typedef enum dbuf_states {
70 DB_UNCACHED,
71 DB_FILL,
72 DB_NOFILL,
73 DB_READ,
74 DB_CACHED,
75 DB_EVICTING
76 } dbuf_states_t;
77
78 struct dnode;
79 struct dmu_tx;
80
81 /*
82 * level = 0 means the user data
83 * level = 1 means the single indirect block
84 * etc.
85 */
86
87 struct dmu_buf_impl;
88
89 typedef enum override_states {
90 DR_NOT_OVERRIDDEN,
91 DR_IN_DMU_SYNC,
92 DR_OVERRIDDEN
93 } override_states_t;
94
95 typedef struct dbuf_dirty_record {
96 /* link on our parents dirty list */
97 list_node_t dr_dirty_node;
98
99 /* transaction group this data will sync in */
100 uint64_t dr_txg;
101
102 /* zio of outstanding write IO */
103 zio_t *dr_zio;
104
105 /* pointer back to our dbuf */
106 struct dmu_buf_impl *dr_dbuf;
107
108 /* pointer to next dirty record */
109 struct dbuf_dirty_record *dr_next;
110
111 /* pointer to parent dirty record */
112 struct dbuf_dirty_record *dr_parent;
113
114 union dirty_types {
115 struct dirty_indirect {
116
117 /* protect access to list */
118 kmutex_t dr_mtx;
119
120 /* Our list of dirty children */
121 list_t dr_children;
122 } di;
123 struct dirty_leaf {
124
125 /*
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.
129 */
130 arc_buf_t *dr_data;
131 blkptr_t dr_overridden_by;
132 override_states_t dr_override_state;
133 uint8_t dr_copies;
134 boolean_t dr_nopwrite;
135 } dl;
136 } dt;
137 } dbuf_dirty_record_t;
138
139 typedef struct dmu_buf_impl {
140 /*
141 * The following members are immutable, with the exception of
142 * db.db_data, which is protected by db_mtx.
143 */
144
145 /* the publicly visible structure */
146 dmu_buf_t db;
147
148 /* the objset we belong to */
149 struct objset *db_objset;
150
151 /*
152 * handle to safely access the dnode we belong to (NULL when evicted)
153 */
154 struct dnode_handle *db_dnode_handle;
155
156 /*
157 * our parent buffer; if the dnode points to us directly,
158 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf
159 * only accessed by sync thread ???
160 * (NULL when evicted)
161 * May change from NULL to non-NULL under the protection of db_mtx
162 * (see dbuf_check_blkptr())
163 */
164 struct dmu_buf_impl *db_parent;
165
166 /*
167 * link for hash table of all dmu_buf_impl_t's
168 */
169 struct dmu_buf_impl *db_hash_next;
170
171 /* our block number */
172 uint64_t db_blkid;
173
174 /*
175 * Pointer to the blkptr_t which points to us. May be NULL if we
176 * don't have one yet. (NULL when evicted)
177 */
178 blkptr_t *db_blkptr;
179
180 /*
181 * Our indirection level. Data buffers have db_level==0.
182 * Indirect buffers which point to data buffers have
183 * db_level==1. etc. Buffers which contain dnodes have
184 * db_level==0, since the dnodes are stored in a file.
185 */
186 uint8_t db_level;
187
188 /* db_mtx protects the members below */
189 kmutex_t db_mtx;
190
191 /*
192 * Current state of the buffer
193 */
194 dbuf_states_t db_state;
195
196 /*
197 * Refcount accessed by dmu_buf_{hold,rele}.
198 * If nonzero, the buffer can't be destroyed.
199 * Protected by db_mtx.
200 */
201 refcount_t db_holds;
202
203 /* buffer holding our data */
204 arc_buf_t *db_buf;
205
206 kcondvar_t db_changed;
207 dbuf_dirty_record_t *db_data_pending;
208
209 /* pointer to most recent dirty record for this buffer */
210 dbuf_dirty_record_t *db_last_dirty;
211
212 /*
213 * Our link on the owner dnodes's dn_dbufs list.
214 * Protected by its dn_dbufs_mtx.
215 */
216 list_node_t db_link;
217
218 /* Data which is unique to data (leaf) blocks: */
219
220 /* User callback information. See dmu_buf_set_user(). */
221 dmu_buf_user_t *db_user;
222
223 uint8_t db_immediate_evict;
224 uint8_t db_freed_in_flight;
225
226 uint8_t db_dirtycnt;
227 } dmu_buf_impl_t;
228
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];
236 } dbuf_hash_table_t;
237
238
239 uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset);
240
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);
245
246 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx);
247
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,
250 void *tag);
251 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create,
252 void *tag, dmu_buf_impl_t **dbp);
253
254 void dbuf_prefetch(struct dnode *dn, uint64_t blkid);
255
256 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag);
257 uint64_t dbuf_refcount(dmu_buf_impl_t *db);
258
259 void dbuf_rele(dmu_buf_impl_t *db, void *tag);
260 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag);
261
262 dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid);
263
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);
273
274 void dbuf_clear(dmu_buf_impl_t *db, list_t *evict_list_p);
275 void dbuf_evict(dmu_buf_impl_t *db, list_t *evict_list_p);
276
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);
281
282 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end,
283 struct dmu_tx *);
284
285 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx);
286
287 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode)
288 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock)
289 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db)))
290 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db)))
291 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db)))
292 #define DB_GET_SPA(_spa_p, _db) { \
293 dnode_t *__dn; \
294 DB_DNODE_ENTER(_db); \
295 __dn = DB_DNODE(_db); \
296 *(_spa_p) = __dn->dn_objset->os_spa; \
297 DB_DNODE_EXIT(_db); \
298 }
299 #define DB_GET_OBJSET(_os_p, _db) { \
300 dnode_t *__dn; \
301 DB_DNODE_ENTER(_db); \
302 __dn = DB_DNODE(_db); \
303 *(_os_p) = __dn->dn_objset; \
304 DB_DNODE_EXIT(_db); \
305 }
306
307 void dbuf_init(void);
308 void dbuf_fini(void);
309
310 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db);
311
312 #define DBUF_GET_BUFC_TYPE(_db) \
313 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)
314
315 #define DBUF_IS_CACHEABLE(_db) \
316 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \
317 (dbuf_is_metadata(_db) && \
318 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))
319
320 #define DBUF_IS_L2CACHEABLE(_db) \
321 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \
322 (dbuf_is_metadata(_db) && \
323 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
324
325 #ifdef ZFS_DEBUG
326
327 /*
328 * There should be a ## between the string literal and fmt, to make it
329 * clear that we're joining two strings together, but gcc does not
330 * support that preprocessor token.
331 */
332 #define dprintf_dbuf(dbuf, fmt, ...) do { \
333 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
334 char __db_buf[32]; \
335 uint64_t __db_obj = (dbuf)->db.db_object; \
336 if (__db_obj == DMU_META_DNODE_OBJECT) \
337 (void) strcpy(__db_buf, "mdn"); \
338 else \
339 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
340 (u_longlong_t)__db_obj); \
341 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
342 "obj=%s lvl=%u blkid=%lld " fmt, \
343 __db_buf, (dbuf)->db_level, \
344 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
345 } \
346 _NOTE(CONSTCOND) } while (0)
347
348 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \
349 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
350 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \
351 sprintf_blkptr(__blkbuf, bp); \
352 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \
353 kmem_free(__blkbuf, BP_SPRINTF_LEN); \
354 } \
355 _NOTE(CONSTCOND) } while (0)
356
357 #define DBUF_VERIFY(db) dbuf_verify(db)
358
359 #else
360
361 #define dprintf_dbuf(db, fmt, ...)
362 #define dprintf_dbuf_bp(db, bp, fmt, ...)
363 #define DBUF_VERIFY(db)
364
365 #endif
366
367
368 #ifdef __cplusplus
369 }
370 #endif
371
372 #endif /* _SYS_DBUF_H */