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) 2013 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 typedef enum dbuf_states {
71 DB_UNCACHED,
72 DB_FILL,
73 DB_NOFILL,
74 DB_READ,
75 DB_CACHED,
76 DB_EVICTING
77 } dbuf_states_t;
78
79 struct dnode;
80 struct dmu_tx;
81
82 /*
83 * level = 0 means the user data
84 * level = 1 means the single indirect block
85 * etc.
86 */
87
88 struct dmu_buf_impl;
89
90 typedef enum override_states {
91 DR_NOT_OVERRIDDEN,
92 DR_IN_DMU_SYNC,
93 DR_OVERRIDDEN
94 } override_states_t;
95
96 typedef struct dbuf_dirty_record {
97 /* link on our parents dirty list */
98 list_node_t dr_dirty_node;
99
100 /* transaction group this data will sync in */
101 uint64_t dr_txg;
102
103 /* zio of outstanding write IO */
104 zio_t *dr_zio;
105
106 /* pointer back to our dbuf */
107 struct dmu_buf_impl *dr_dbuf;
108
109 /* pointer to next dirty record */
110 struct dbuf_dirty_record *dr_next;
111
112 /* pointer to parent dirty record */
113 struct dbuf_dirty_record *dr_parent;
114
115 /* How much space was changed to dsl_pool_dirty_space() for this? */
116 unsigned int dr_accounted;
117
118 union dirty_types {
119 struct dirty_indirect {
120
121 /* protect access to list */
122 kmutex_t dr_mtx;
123
124 /* Our list of dirty children */
125 list_t dr_children;
126 } di;
127 struct dirty_leaf {
128
129 /*
130 * dr_data is set when we dirty the buffer
131 * so that we can retain the pointer even if it
132 * gets COW'd in a subsequent transaction group.
133 */
134 arc_buf_t *dr_data;
135 blkptr_t dr_overridden_by;
136 override_states_t dr_override_state;
137 uint8_t dr_copies;
138 boolean_t dr_nopwrite;
139 } dl;
140 } dt;
141 } dbuf_dirty_record_t;
142
143 typedef struct dmu_buf_impl {
144 /*
145 * The following members are immutable, with the exception of
146 * db.db_data, which is protected by db_mtx.
147 */
148
149 /* the publicly visible structure */
150 dmu_buf_t db;
151
152 /* the objset we belong to */
153 struct objset *db_objset;
154
155 /*
156 * handle to safely access the dnode we belong to (NULL when evicted)
157 */
158 struct dnode_handle *db_dnode_handle;
159
160 /*
161 * our parent buffer; if the dnode points to us directly,
162 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf
163 * only accessed by sync thread ???
164 * (NULL when evicted)
165 * May change from NULL to non-NULL under the protection of db_mtx
166 * (see dbuf_check_blkptr())
167 */
168 struct dmu_buf_impl *db_parent;
169
170 /*
171 * link for hash table of all dmu_buf_impl_t's
172 */
173 struct dmu_buf_impl *db_hash_next;
174
175 /* our block number */
176 uint64_t db_blkid;
177
178 /*
179 * Pointer to the blkptr_t which points to us. May be NULL if we
180 * don't have one yet. (NULL when evicted)
181 */
182 blkptr_t *db_blkptr;
183
184 /*
185 * Our indirection level. Data buffers have db_level==0.
186 * Indirect buffers which point to data buffers have
187 * db_level==1. etc. Buffers which contain dnodes have
188 * db_level==0, since the dnodes are stored in a file.
189 */
190 uint8_t db_level;
191
192 /* db_mtx protects the members below */
193 kmutex_t db_mtx;
194
195 /*
196 * Current state of the buffer
197 */
198 dbuf_states_t db_state;
199
200 /*
201 * Refcount accessed by dmu_buf_{hold,rele}.
202 * If nonzero, the buffer can't be destroyed.
203 * Protected by db_mtx.
204 */
205 refcount_t db_holds;
206
207 /* buffer holding our data */
208 arc_buf_t *db_buf;
209
210 kcondvar_t db_changed;
211 dbuf_dirty_record_t *db_data_pending;
212
213 /* pointer to most recent dirty record for this buffer */
214 dbuf_dirty_record_t *db_last_dirty;
215
216 /*
217 * Our link on the owner dnodes's dn_dbufs list.
218 * Protected by its dn_dbufs_mtx.
219 */
220 list_node_t db_link;
221
222 /* Data which is unique to data (leaf) blocks: */
223
224 /* stuff we store for the user (see dmu_buf_set_user) */
225 void *db_user_ptr;
226 void **db_user_data_ptr_ptr;
227 dmu_buf_evict_func_t *db_evict_func;
228
229 uint8_t db_immediate_evict;
230 uint8_t db_freed_in_flight;
231
232 uint8_t db_dirtycnt;
233 } dmu_buf_impl_t;
234
235 /* Note: the dbuf hash table is exposed only for the mdb module */
236 #define DBUF_MUTEXES 256
237 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)])
238 typedef struct dbuf_hash_table {
239 uint64_t hash_table_mask;
240 dmu_buf_impl_t **hash_table;
241 kmutex_t hash_mutexes[DBUF_MUTEXES];
242 } dbuf_hash_table_t;
243
244
245 uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset);
246
247 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data);
248 void dbuf_create_bonus(struct dnode *dn);
249 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx);
250 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag);
251
252 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx);
253
254 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag);
255 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid,
256 void *tag);
257 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create,
258 void *tag, dmu_buf_impl_t **dbp);
259
260 void dbuf_prefetch(struct dnode *dn, uint64_t blkid, zio_priority_t prio);
261
262 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag);
263 uint64_t dbuf_refcount(dmu_buf_impl_t *db);
264
265 void dbuf_rele(dmu_buf_impl_t *db, void *tag);
266 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag);
267
268 dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid);
269
270 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags);
271 void dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
272 void dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx);
273 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
274 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx);
275 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx);
276 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx);
277 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
278 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db);
279
280 void dbuf_clear(dmu_buf_impl_t *db);
281 void dbuf_evict(dmu_buf_impl_t *db);
282
283 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
284 void dbuf_unoverride(dbuf_dirty_record_t *dr);
285 void dbuf_sync_list(list_t *list, dmu_tx_t *tx);
286 void dbuf_release_bp(dmu_buf_impl_t *db);
287
288 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end,
289 struct dmu_tx *);
290
291 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx);
292
293 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode)
294 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock)
295 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db)))
296 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db)))
297 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db)))
298 #define DB_GET_SPA(_spa_p, _db) { \
299 dnode_t *__dn; \
300 DB_DNODE_ENTER(_db); \
301 __dn = DB_DNODE(_db); \
302 *(_spa_p) = __dn->dn_objset->os_spa; \
303 DB_DNODE_EXIT(_db); \
304 }
305 #define DB_GET_OBJSET(_os_p, _db) { \
306 dnode_t *__dn; \
307 DB_DNODE_ENTER(_db); \
308 __dn = DB_DNODE(_db); \
309 *(_os_p) = __dn->dn_objset; \
310 DB_DNODE_EXIT(_db); \
311 }
312
313 void dbuf_init(void);
314 void dbuf_fini(void);
315
316 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db);
317
318 #define DBUF_GET_BUFC_TYPE(_db) \
319 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)
320
321 #define DBUF_IS_CACHEABLE(_db) \
322 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \
323 (dbuf_is_metadata(_db) && \
324 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))
325
326 #define DBUF_IS_L2CACHEABLE(_db) \
327 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \
328 (dbuf_is_metadata(_db) && \
329 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
330
331 #define DBUF_IS_L2COMPRESSIBLE(_db) \
332 ((_db)->db_objset->os_compress != ZIO_COMPRESS_OFF)
333
334 #ifdef ZFS_DEBUG
335
336 /*
337 * There should be a ## between the string literal and fmt, to make it
338 * clear that we're joining two strings together, but gcc does not
339 * support that preprocessor token.
340 */
341 #define dprintf_dbuf(dbuf, fmt, ...) do { \
342 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
343 char __db_buf[32]; \
344 uint64_t __db_obj = (dbuf)->db.db_object; \
345 if (__db_obj == DMU_META_DNODE_OBJECT) \
346 (void) strcpy(__db_buf, "mdn"); \
347 else \
348 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
349 (u_longlong_t)__db_obj); \
350 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
351 "obj=%s lvl=%u blkid=%lld " fmt, \
352 __db_buf, (dbuf)->db_level, \
353 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
354 } \
355 _NOTE(CONSTCOND) } while (0)
356
357 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \
358 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
359 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \
360 sprintf_blkptr(__blkbuf, bp); \
361 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \
362 kmem_free(__blkbuf, BP_SPRINTF_LEN); \
363 } \
364 _NOTE(CONSTCOND) } while (0)
365
366 #define DBUF_VERIFY(db) dbuf_verify(db)
367
368 #else
369
370 #define dprintf_dbuf(db, fmt, ...)
371 #define dprintf_dbuf_bp(db, bp, fmt, ...)
372 #define DBUF_VERIFY(db)
373
374 #endif
375
376
377 #ifdef __cplusplus
378 }
379 #endif
380
381 #endif /* _SYS_DBUF_H */