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, 2015 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 #include <sys/multilist.h>
40
41 #ifdef __cplusplus
42 extern "C" {
43 #endif
44
45 #define IN_DMU_SYNC 2
46
47 /*
48 * define flags for dbuf_read
49 */
50
51 #define DB_RF_MUST_SUCCEED (1 << 0)
52 #define DB_RF_CANFAIL (1 << 1)
53 #define DB_RF_HAVESTRUCT (1 << 2)
54 #define DB_RF_NOPREFETCH (1 << 3)
55 #define DB_RF_NEVERWAIT (1 << 4)
56 #define DB_RF_CACHED (1 << 5)
57
58 /*
59 * The simplified state transition diagram for dbufs looks like:
60 *
61 * +----> READ ----+
62 * | |
63 * | V
64 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free)
65 * | ^ ^
66 * | | |
67 * +----> FILL ----+ |
68 * | |
69 * | |
70 * +--------> NOFILL -------+
71 *
72 * DB_SEARCH is an invalid state for a dbuf. It is used by dbuf_free_range
73 * to find all dbufs in a range of a dnode and must be less than any other
74 * dbuf_states_t (see comment on dn_dbufs in dnode.h).
75 */
76 typedef enum dbuf_states {
77 DB_SEARCH = -1,
78 DB_UNCACHED,
79 DB_FILL,
80 DB_NOFILL,
81 DB_READ,
82 DB_CACHED,
83 DB_EVICTING
84 } dbuf_states_t;
85
86 struct dnode;
87 struct dmu_tx;
88
89 /*
90 * level = 0 means the user data
91 * level = 1 means the single indirect block
92 * etc.
93 */
94
95 struct dmu_buf_impl;
96
97 typedef enum override_states {
98 DR_NOT_OVERRIDDEN,
99 DR_IN_DMU_SYNC,
100 DR_OVERRIDDEN
101 } override_states_t;
102
103 typedef struct dbuf_dirty_record {
104 /* link on our parents dirty list */
105 list_node_t dr_dirty_node;
106
107 /* transaction group this data will sync in */
108 uint64_t dr_txg;
109
110 /* zio of outstanding write IO */
111 zio_t *dr_zio;
112
113 /* pointer back to our dbuf */
114 struct dmu_buf_impl *dr_dbuf;
115
116 /* pointer to next dirty record */
117 struct dbuf_dirty_record *dr_next;
118
119 /* pointer to parent dirty record */
120 struct dbuf_dirty_record *dr_parent;
121
122 /* How much space was changed to dsl_pool_dirty_space() for this? */
123 unsigned int dr_accounted;
124
125 /* A copy of the bp that points to us */
126 blkptr_t dr_bp_copy;
127
128 union dirty_types {
129 struct dirty_indirect {
130
131 /* protect access to list */
132 kmutex_t dr_mtx;
133
134 /* Our list of dirty children */
135 list_t dr_children;
136 } di;
137 struct dirty_leaf {
138
139 /*
140 * dr_data is set when we dirty the buffer
141 * so that we can retain the pointer even if it
142 * gets COW'd in a subsequent transaction group.
143 */
144 arc_buf_t *dr_data;
145 blkptr_t dr_overridden_by;
146 override_states_t dr_override_state;
147 uint8_t dr_copies;
148 boolean_t dr_nopwrite;
149 } dl;
150 } dt;
151 } dbuf_dirty_record_t;
152
153 typedef struct dmu_buf_impl {
154 /*
155 * The following members are immutable, with the exception of
156 * db.db_data, which is protected by db_mtx.
157 */
158
159 /* the publicly visible structure */
160 dmu_buf_t db;
161
162 /* the objset we belong to */
163 struct objset *db_objset;
164
165 /*
166 * handle to safely access the dnode we belong to (NULL when evicted)
167 */
168 struct dnode_handle *db_dnode_handle;
169
170 /*
171 * our parent buffer; if the dnode points to us directly,
172 * db_parent == db_dnode_handle->dnh_dnode->dn_dbuf
173 * only accessed by sync thread ???
174 * (NULL when evicted)
175 * May change from NULL to non-NULL under the protection of db_mtx
176 * (see dbuf_check_blkptr())
177 */
178 struct dmu_buf_impl *db_parent;
179
180 /*
181 * link for hash table of all dmu_buf_impl_t's
182 */
183 struct dmu_buf_impl *db_hash_next;
184
185 /* our block number */
186 uint64_t db_blkid;
187
188 /*
189 * Pointer to the blkptr_t which points to us. May be NULL if we
190 * don't have one yet. (NULL when evicted)
191 */
192 blkptr_t *db_blkptr;
193
194 /*
195 * Our indirection level. Data buffers have db_level==0.
196 * Indirect buffers which point to data buffers have
197 * db_level==1. etc. Buffers which contain dnodes have
198 * db_level==0, since the dnodes are stored in a file.
199 */
200 uint8_t db_level;
201
202 /* db_mtx protects the members below */
203 kmutex_t db_mtx;
204
205 /*
206 * Current state of the buffer
207 */
208 dbuf_states_t db_state;
209
210 /*
211 * Refcount accessed by dmu_buf_{hold,rele}.
212 * If nonzero, the buffer can't be destroyed.
213 * Protected by db_mtx.
214 */
215 refcount_t db_holds;
216
217 /* buffer holding our data */
218 arc_buf_t *db_buf;
219
220 kcondvar_t db_changed;
221 dbuf_dirty_record_t *db_data_pending;
222
223 /* pointer to most recent dirty record for this buffer */
224 dbuf_dirty_record_t *db_last_dirty;
225
226 /*
227 * Our link on the owner dnodes's dn_dbufs list.
228 * Protected by its dn_dbufs_mtx.
229 */
230 avl_node_t db_link;
231
232 /*
233 * Link in dbuf_cache.
234 */
235 multilist_node_t db_cache_link;
236
237 /* Data which is unique to data (leaf) blocks: */
238
239 /* User callback information. */
240 dmu_buf_user_t *db_user;
241
242 /*
243 * Evict user data as soon as the dirty and reference
244 * counts are equal.
245 */
246 uint8_t db_user_immediate_evict;
247
248 /*
249 * This block was freed while a read or write was
250 * active.
251 */
252 uint8_t db_freed_in_flight;
253
254 /*
255 * dnode_evict_dbufs() or dnode_evict_bonus() tried to
256 * evict this dbuf, but couldn't due to outstanding
257 * references. Evict once the refcount drops to 0.
258 */
259 uint8_t db_pending_evict;
260
261 uint8_t db_dirtycnt;
262 } dmu_buf_impl_t;
263
264 /* Note: the dbuf hash table is exposed only for the mdb module */
265 #define DBUF_MUTEXES 256
266 #define DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)])
267 typedef struct dbuf_hash_table {
268 uint64_t hash_table_mask;
269 dmu_buf_impl_t **hash_table;
270 kmutex_t hash_mutexes[DBUF_MUTEXES];
271 } dbuf_hash_table_t;
272
273 uint64_t dbuf_whichblock(struct dnode *di, int64_t level, uint64_t offset);
274
275 dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data);
276 void dbuf_create_bonus(struct dnode *dn);
277 int dbuf_spill_set_blksz(dmu_buf_t *db, uint64_t blksz, dmu_tx_t *tx);
278 void dbuf_spill_hold(struct dnode *dn, dmu_buf_impl_t **dbp, void *tag);
279
280 void dbuf_rm_spill(struct dnode *dn, dmu_tx_t *tx);
281
282 dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag);
283 dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid,
284 void *tag);
285 int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid,
286 boolean_t fail_sparse, boolean_t fail_uncached,
287 void *tag, dmu_buf_impl_t **dbp);
288
289 void dbuf_prefetch(struct dnode *dn, int64_t level, uint64_t blkid,
290 zio_priority_t prio, arc_flags_t aflags);
291
292 void dbuf_add_ref(dmu_buf_impl_t *db, void *tag);
293 boolean_t dbuf_try_add_ref(dmu_buf_t *db, objset_t *os, uint64_t obj,
294 uint64_t blkid, void *tag);
295 uint64_t dbuf_refcount(dmu_buf_impl_t *db);
296
297 void dbuf_rele(dmu_buf_impl_t *db, void *tag);
298 void dbuf_rele_and_unlock(dmu_buf_impl_t *db, void *tag);
299
300 dmu_buf_impl_t *dbuf_find(struct objset *os, uint64_t object, uint8_t level,
301 uint64_t blkid);
302
303 int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags);
304 void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
305 void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx);
306 void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx);
307 void dbuf_assign_arcbuf(dmu_buf_impl_t *db, arc_buf_t *buf, dmu_tx_t *tx);
308 dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
309 arc_buf_t *dbuf_loan_arcbuf(dmu_buf_impl_t *db);
310 void dmu_buf_write_embedded(dmu_buf_t *dbuf, void *data,
311 bp_embedded_type_t etype, enum zio_compress comp,
312 int uncompressed_size, int compressed_size, int byteorder, dmu_tx_t *tx);
313
314 void dbuf_destroy(dmu_buf_impl_t *db);
315
316 void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
317 void dbuf_unoverride(dbuf_dirty_record_t *dr);
318 void dbuf_sync_list(list_t *list, int level, dmu_tx_t *tx);
319 void dbuf_release_bp(dmu_buf_impl_t *db);
320
321 boolean_t dbuf_can_remap(const dmu_buf_impl_t *buf);
322
323 void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end,
324 struct dmu_tx *);
325
326 void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx);
327
328 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode)
329 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock)
330 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db)))
331 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db)))
332 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db)))
333
334 void dbuf_init(void);
335 void dbuf_fini(void);
336
337 boolean_t dbuf_is_metadata(dmu_buf_impl_t *db);
338
339 #define DBUF_GET_BUFC_TYPE(_db) \
340 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)
341
342 #define DBUF_IS_CACHEABLE(_db) \
343 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \
344 (dbuf_is_metadata(_db) && \
345 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))
346
347 #define DBUF_IS_L2CACHEABLE(_db) \
348 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \
349 (dbuf_is_metadata(_db) && \
350 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
351
352 #define DNODE_LEVEL_IS_L2CACHEABLE(_dn, _level) \
353 ((_dn)->dn_objset->os_secondary_cache == ZFS_CACHE_ALL || \
354 (((_level) > 0 || \
355 DMU_OT_IS_METADATA((_dn)->dn_handle->dnh_dnode->dn_type)) && \
356 ((_dn)->dn_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
357
358 #ifdef ZFS_DEBUG
359
360 /*
361 * There should be a ## between the string literal and fmt, to make it
362 * clear that we're joining two strings together, but gcc does not
363 * support that preprocessor token.
364 */
365 #define dprintf_dbuf(dbuf, fmt, ...) do { \
366 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
367 char __db_buf[32]; \
368 uint64_t __db_obj = (dbuf)->db.db_object; \
369 if (__db_obj == DMU_META_DNODE_OBJECT) \
370 (void) strcpy(__db_buf, "mdn"); \
371 else \
372 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
373 (u_longlong_t)__db_obj); \
374 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
375 "obj=%s lvl=%u blkid=%lld " fmt, \
376 __db_buf, (dbuf)->db_level, \
377 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
378 } \
379 _NOTE(CONSTCOND) } while (0)
380
381 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \
382 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
383 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \
384 snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \
385 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \
386 kmem_free(__blkbuf, BP_SPRINTF_LEN); \
387 } \
388 _NOTE(CONSTCOND) } while (0)
389
390 #define DBUF_VERIFY(db) dbuf_verify(db)
391
392 #else
393
394 #define dprintf_dbuf(db, fmt, ...)
395 #define dprintf_dbuf_bp(db, bp, fmt, ...)
396 #define DBUF_VERIFY(db)
397
398 #endif
399
400
401 #ifdef __cplusplus
402 }
403 #endif
404
405 #endif /* _SYS_DBUF_H */