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