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