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 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
26 */
27
28 #ifndef _SYS_DBUF_H
29 #define _SYS_DBUF_H
30
31 #include <sys/dmu.h>
32 #include <sys/spa.h>
33 #include <sys/txg.h>
34 #include <sys/zio.h>
35 #include <sys/arc.h>
36 #include <sys/zfs_context.h>
37 #include <sys/refcount.h>
38 #include <sys/zrlock.h>
39
40 #ifdef __cplusplus
41 extern "C" {
42 #endif
43
44 #define IN_DMU_SYNC 2
45
46 /*
47 * define flags for dbuf_read
48 */
49
50 #define DB_RF_MUST_SUCCEED (1 << 0)
51 #define DB_RF_CANFAIL (1 << 1)
52 #define DB_RF_HAVESTRUCT (1 << 2)
53 #define DB_RF_NOPREFETCH (1 << 3)
54 #define DB_RF_NEVERWAIT (1 << 4)
55 #define DB_RF_CACHED (1 << 5)
56
57 /*
58 * The simplified state transition diagram for dbufs looks like:
59 *
60 * +----> READ ----+
61 * | |
62 * | V
63 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free)
64 * | ^ ^
65 * | | |
66 * +----> FILL ----+ |
67 * | |
68 * | |
69 * +--------> NOFILL -------+
70 *
71 * DB_SEARCH is an invalid state for a dbuf. It is used by dbuf_free_range
72 * to find all dbufs in a range of a dnode and must be less than any other
73 * dbuf_states_t (see comment on dn_dbufs in dnode.h).
74 */
75 typedef enum dbuf_states {
76 DB_SEARCH = -1,
77 DB_UNCACHED,
78 DB_FILL,
79 DB_NOFILL,
80 DB_READ,
81 DB_CACHED,
82 DB_EVICTING
83 } dbuf_states_t;
84
85 struct dnode;
86 struct dmu_tx;
87
88 /*
89 * level = 0 means the user data
90 * level = 1 means the single indirect block
91 * etc.
92 */
93
94 struct dmu_buf_impl;
95
96 typedef enum override_states {
97 DR_NOT_OVERRIDDEN,
98 DR_IN_DMU_SYNC,
99 DR_OVERRIDDEN
100 } override_states_t;
101
102 typedef struct dbuf_dirty_record {
103 /* link on our parents dirty list */
104 list_node_t dr_dirty_node;
105
106 /* transaction group this data will sync in */
107 uint64_t dr_txg;
108
109 /* zio of outstanding write IO */
110 zio_t *dr_zio;
111
112 /* pointer back to our dbuf */
113 struct dmu_buf_impl *dr_dbuf;
114
115 /* pointer to next dirty record */
116 struct dbuf_dirty_record *dr_next;
117
118 /* pointer to parent dirty record */
119 struct dbuf_dirty_record *dr_parent;
120
121 /* How much space was changed to dsl_pool_dirty_space() for this? */
122 unsigned int dr_accounted;
123
124 /* A copy of the bp that points to us */
125 blkptr_t dr_bp_copy;
126
127 union dirty_types {
128 struct dirty_indirect {
129
130 /* protect access to list */
131 kmutex_t dr_mtx;
132
133 /* Our list of dirty children */
134 list_t dr_children;
135 } di;
136 struct dirty_leaf {
137
138 /*
139 * dr_data is set when we dirty the buffer
140 * so that we can retain the pointer even if it
141 * gets COW'd in a subsequent transaction group.
142 */
143 arc_buf_t *dr_data;
144 blkptr_t dr_overridden_by;
145 override_states_t dr_override_state;
146 uint8_t dr_copies;
147 boolean_t dr_nopwrite;
148 } dl;
149 } dt;
150 } dbuf_dirty_record_t;
151
152 typedef struct dmu_buf_impl {
153 /*
154 * The following members are immutable, with the exception of
155 * db.db_data, which is protected by db_mtx.
156 */
157
158 /* the publicly visible structure */
159 dmu_buf_t db;
160
161 /* the objset we belong to */
162 struct objset *db_objset;
163
164 /*
165 * handle to safely access the dnode we belong to (NULL when evicted)
166 */
167 struct dnode_handle *db_dnode_handle;
168
169 /*
170 * our parent buffer; if the dnode points to us directly,
171 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf
172 * only accessed by sync thread ???
173 * (NULL when evicted)
174 * May change from NULL to non-NULL under the protection of db_mtx
175 * (see dbuf_check_blkptr())
176 */
177 struct dmu_buf_impl *db_parent;
178
179 /*
180 * link for hash table of all dmu_buf_impl_t's
181 */
182 struct dmu_buf_impl *db_hash_next;
183
184 /* our block number */
185 uint64_t db_blkid;
186
187 /*
188 * Pointer to the blkptr_t which points to us. May be NULL if we
189 * don't have one yet. (NULL when evicted)
190 */
191 blkptr_t *db_blkptr;
192
193 /*
194 * Our indirection level. Data buffers have db_level==0.
195 * Indirect buffers which point to data buffers have
196 * db_level==1. etc. Buffers which contain dnodes have
197 * db_level==0, since the dnodes are stored in a file.
198 */
199 uint8_t db_level;
200
201 /* db_mtx protects the members below */
202 kmutex_t db_mtx;
203
204 /*
205 * Current state of the buffer
206 */
207 dbuf_states_t db_state;
208
209 /*
210 * Refcount accessed by dmu_buf_{hold,rele}.
211 * If nonzero, the buffer can't be destroyed.
212 * Protected by db_mtx.
213 */
214 refcount_t db_holds;
215
216 /* buffer holding our data */
217 arc_buf_t *db_buf;
218
219 kcondvar_t db_changed;
220 dbuf_dirty_record_t *db_data_pending;
221
222 /* pointer to most recent dirty record for this buffer */
223 dbuf_dirty_record_t *db_last_dirty;
224
225 /*
226 * Our link on the owner dnodes's dn_dbufs list.
227 * Protected by its dn_dbufs_mtx.
228 */
229 avl_node_t db_link;
230
231 /* Data which is unique to data (leaf) blocks: */
232
233 /* User callback information. */
234 dmu_buf_user_t *db_user;
235
236 uint8_t db_immediate_evict;
237 uint8_t db_freed_in_flight;
238
239 uint8_t db_dirtycnt;
240 } dmu_buf_impl_t;
241
242 /* Note: the dbuf hash table is exposed only for the mdb module */
243 #define DBUF_MUTEXES 256
244 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)])
245 typedef struct dbuf_hash_table {
246 uint64_t hash_table_mask;
247 dmu_buf_impl_t **hash_table;
248 kmutex_t hash_mutexes[DBUF_MUTEXES];
249 } dbuf_hash_table_t;
250
251
252 uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset);
253
254 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data);
255 void dbuf_create_bonus(struct dnode *dn);
256 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx);
257 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag);
258
259 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx);
260
261 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag);
262 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid,
263 void *tag);
264 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create,
265 void *tag, dmu_buf_impl_t **dbp);
266
267 void dbuf_prefetch(struct dnode *dn, uint64_t blkid, zio_priority_t prio);
268
269 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag);
270 boolean_t dbuf_try_add_ref(dmu_buf_t *db, objset_t *os, uint64_t obj,
271 uint64_t blkid, void *tag);
272 uint64_t dbuf_refcount(dmu_buf_impl_t *db);
273
274 void dbuf_rele(dmu_buf_impl_t *db, void *tag);
275 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag);
276
277 dmu_buf_impl_t *dbuf_find(struct objset *os, uint64_t object, uint8_t level,
278 uint64_t blkid);
279
280 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags);
281 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
282 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx);
283 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx);
284 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx);
285 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
286 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db);
287 void dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data,
288 bp_embedded_type_t etype, enum zio_compress comp,
289 int uncompressed_size, int compressed_size, int byteorder, dmu_tx_t *tx);
290
291 void dbuf_clear(dmu_buf_impl_t *db);
292 void dbuf_evict(dmu_buf_impl_t *db);
293
294 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
295 void dbuf_unoverride(dbuf_dirty_record_t *dr);
296 void dbuf_sync_list(list_t *list, dmu_tx_t *tx);
297 void dbuf_release_bp(dmu_buf_impl_t *db);
298
299 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end,
300 struct dmu_tx *);
301
302 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx);
303
304 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode)
305 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock)
306 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db)))
307 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db)))
308 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db)))
309
310 void dbuf_init(void);
311 void dbuf_fini(void);
312
313 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db);
314
315 #define DBUF_GET_BUFC_TYPE(_db) \
316 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)
317
318 #define DBUF_IS_CACHEABLE(_db) \
319 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \
320 (dbuf_is_metadata(_db) && \
321 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))
322
323 #define DBUF_IS_L2CACHEABLE(_db) \
324 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \
325 (dbuf_is_metadata(_db) && \
326 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
327
328 #define DBUF_IS_L2COMPRESSIBLE(_db) \
329 ((_db)->db_objset->os_compress != ZIO_COMPRESS_OFF || \
330 (dbuf_is_metadata(_db) && zfs_mdcomp_disable == B_FALSE))
331
332 #ifdef ZFS_DEBUG
333
334 /*
335 * There should be a ## between the string literal and fmt, to make it
336 * clear that we're joining two strings together, but gcc does not
337 * support that preprocessor token.
338 */
339 #define dprintf_dbuf(dbuf, fmt, ...) do { \
340 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
341 char __db_buf[32]; \
342 uint64_t __db_obj = (dbuf)->db.db_object; \
343 if (__db_obj == DMU_META_DNODE_OBJECT) \
344 (void) strcpy(__db_buf, "mdn"); \
345 else \
346 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
347 (u_longlong_t)__db_obj); \
348 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
349 "obj=%s lvl=%u blkid=%lld " fmt, \
350 __db_buf, (dbuf)->db_level, \
351 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
352 } \
353 _NOTE(CONSTCOND) } while (0)
354
355 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \
356 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
357 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \
358 snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \
359 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \
360 kmem_free(__blkbuf, BP_SPRINTF_LEN); \
361 } \
362 _NOTE(CONSTCOND) } while (0)
363
364 #define DBUF_VERIFY(db) dbuf_verify(db)
365
366 #else
367
368 #define dprintf_dbuf(db, fmt, ...)
369 #define dprintf_dbuf_bp(db, bp, fmt, ...)
370 #define DBUF_VERIFY(db)
371
372 #endif
373
374
375 #ifdef __cplusplus
376 }
377 #endif
378
379 #endif /* _SYS_DBUF_H */