summaryrefslogtreecommitdiffstats
path: root/module/zfs/include/sys/dbuf.h
blob: 75ce27264e3ce93f617e1ce01673f67c106d42a8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#ifndef	_SYS_DBUF_H
#define	_SYS_DBUF_H

#include <sys/dmu.h>
#include <sys/spa.h>
#include <sys/txg.h>
#include <sys/zio.h>
#include <sys/arc.h>
#include <sys/zfs_context.h>
#include <sys/refcount.h>

#ifdef	__cplusplus
extern "C" {
#endif

#define	DB_BONUS_BLKID (-1ULL)
#define	IN_DMU_SYNC 2

/*
 * define flags for dbuf_read
 */

#define	DB_RF_MUST_SUCCEED	(1 << 0)
#define	DB_RF_CANFAIL		(1 << 1)
#define	DB_RF_HAVESTRUCT	(1 << 2)
#define	DB_RF_NOPREFETCH	(1 << 3)
#define	DB_RF_NEVERWAIT		(1 << 4)
#define	DB_RF_CACHED		(1 << 5)

/*
 * The simplified state transition diagram for dbufs looks like:
 *
 *		+----> READ ----+
 *		|		|
 *		|		V
 *  (alloc)-->UNCACHED	     CACHED-->EVICTING-->(free)
 *		|		^	 ^
 *		|		|	 |
 *		+----> FILL ----+	 |
 *		|			 |
 *		|			 |
 *		+--------> NOFILL -------+
 */
typedef enum dbuf_states {
	DB_UNCACHED,
	DB_FILL,
	DB_NOFILL,
	DB_READ,
	DB_CACHED,
	DB_EVICTING
} dbuf_states_t;

struct objset_impl;
struct dnode;
struct dmu_tx;

/*
 * level = 0 means the user data
 * level = 1 means the single indirect block
 * etc.
 */

#define	LIST_LINK_INACTIVE(link) \
	((link)->list_next == NULL && (link)->list_prev == NULL)

struct dmu_buf_impl;

typedef enum override_states {
	DR_NOT_OVERRIDDEN,
	DR_IN_DMU_SYNC,
	DR_OVERRIDDEN
} override_states_t;

typedef struct dbuf_dirty_record {
	/* link on our parents dirty list */
	list_node_t dr_dirty_node;

	/* transaction group this data will sync in */
	uint64_t dr_txg;

	/* zio of outstanding write IO */
	zio_t *dr_zio;

	/* pointer back to our dbuf */
	struct dmu_buf_impl *dr_dbuf;

	/* pointer to next dirty record */
	struct dbuf_dirty_record *dr_next;

	/* pointer to parent dirty record */
	struct dbuf_dirty_record *dr_parent;

	union dirty_types {
		struct dirty_indirect {

			/* protect access to list */
			kmutex_t dr_mtx;

			/* Our list of dirty children */
			list_t dr_children;
		} di;
		struct dirty_leaf {

			/*
			 * dr_data is set when we dirty the buffer
			 * so that we can retain the pointer even if it
			 * gets COW'd in a subsequent transaction group.
			 */
			arc_buf_t *dr_data;
			blkptr_t dr_overridden_by;
			override_states_t dr_override_state;
		} dl;
	} dt;
} dbuf_dirty_record_t;

typedef struct dmu_buf_impl {
	/*
	 * The following members are immutable, with the exception of
	 * db.db_data, which is protected by db_mtx.
	 */

	/* the publicly visible structure */
	dmu_buf_t db;

	/* the objset we belong to */
	struct objset_impl *db_objset;

	/*
	 * the dnode we belong to (NULL when evicted)
	 */
	struct dnode *db_dnode;

	/*
	 * our parent buffer; if the dnode points to us directly,
	 * db_parent == db_dnode->dn_dbuf
	 * only accessed by sync thread ???
	 * (NULL when evicted)
	 */
	struct dmu_buf_impl *db_parent;

	/*
	 * link for hash table of all dmu_buf_impl_t's
	 */
	struct dmu_buf_impl *db_hash_next;

	/* our block number */
	uint64_t db_blkid;

	/*
	 * Pointer to the blkptr_t which points to us. May be NULL if we
	 * don't have one yet. (NULL when evicted)
	 */
	blkptr_t *db_blkptr;

	/*
	 * Our indirection level.  Data buffers have db_level==0.
	 * Indirect buffers which point to data buffers have
	 * db_level==1. etc.  Buffers which contain dnodes have
	 * db_level==0, since the dnodes are stored in a file.
	 */
	uint8_t db_level;

	/* db_mtx protects the members below */
	kmutex_t db_mtx;

	/*
	 * Current state of the buffer
	 */
	dbuf_states_t db_state;

	/*
	 * Refcount accessed by dmu_buf_{hold,rele}.
	 * If nonzero, the buffer can't be destroyed.
	 * Protected by db_mtx.
	 */
	refcount_t db_holds;

	/* buffer holding our data */
	arc_buf_t *db_buf;

	kcondvar_t db_changed;
	dbuf_dirty_record_t *db_data_pending;

	/* pointer to most recent dirty record for this buffer */
	dbuf_dirty_record_t *db_last_dirty;

	/*
	 * Our link on the owner dnodes's dn_dbufs list.
	 * Protected by its dn_dbufs_mtx.
	 */
	list_node_t db_link;

	/* Data which is unique to data (leaf) blocks: */

	/* stuff we store for the user (see dmu_buf_set_user) */
	void *db_user_ptr;
	void **db_user_data_ptr_ptr;
	dmu_buf_evict_func_t *db_evict_func;

	uint8_t db_immediate_evict;
	uint8_t db_freed_in_flight;

	uint8_t db_dirtycnt;
} dmu_buf_impl_t;

/* Note: the dbuf hash table is exposed only for the mdb module */
#define	DBUF_MUTEXES 256
#define	DBUF_HASH_MUTEX(h, idx) (&(h)->hash_mutexes[(idx) & (DBUF_MUTEXES-1)])
typedef struct dbuf_hash_table {
	uint64_t hash_table_mask;
	dmu_buf_impl_t **hash_table;
	kmutex_t hash_mutexes[DBUF_MUTEXES];
} dbuf_hash_table_t;


uint64_t dbuf_whichblock(struct dnode *di, uint64_t offset);

dmu_buf_impl_t *dbuf_create_tlib(struct dnode *dn, char *data);
void dbuf_create_bonus(struct dnode *dn);

dmu_buf_impl_t *dbuf_hold(struct dnode *dn, uint64_t blkid, void *tag);
dmu_buf_impl_t *dbuf_hold_level(struct dnode *dn, int level, uint64_t blkid,
    void *tag);
int dbuf_hold_impl(struct dnode *dn, uint8_t level, uint64_t blkid, int create,
    void *tag, dmu_buf_impl_t **dbp);

void dbuf_prefetch(struct dnode *dn, uint64_t blkid);

void dbuf_add_ref(dmu_buf_impl_t *db, void *tag);
uint64_t dbuf_refcount(dmu_buf_impl_t *db);

void dbuf_rele(dmu_buf_impl_t *db, void *tag);

dmu_buf_impl_t *dbuf_find(struct dnode *dn, uint8_t level, uint64_t blkid);

int dbuf_read(dmu_buf_impl_t *db, zio_t *zio, uint32_t flags);
void dbuf_will_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
void dbuf_fill_done(dmu_buf_impl_t *db, dmu_tx_t *tx);
void dmu_buf_will_not_fill(dmu_buf_t *db, dmu_tx_t *tx);
void dmu_buf_will_fill(dmu_buf_t *db, dmu_tx_t *tx);
void dmu_buf_fill_done(dmu_buf_t *db, dmu_tx_t *tx);
dbuf_dirty_record_t *dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx);

void dbuf_clear(dmu_buf_impl_t *db);
void dbuf_evict(dmu_buf_impl_t *db);

void dbuf_setdirty(dmu_buf_impl_t *db, dmu_tx_t *tx);
void dbuf_unoverride(dbuf_dirty_record_t *dr);
void dbuf_sync_list(list_t *list, dmu_tx_t *tx);

void dbuf_free_range(struct dnode *dn, uint64_t start, uint64_t end,
    struct dmu_tx *);

void dbuf_new_size(dmu_buf_impl_t *db, int size, dmu_tx_t *tx);

void dbuf_init(void);
void dbuf_fini(void);

#define	DBUF_IS_METADATA(db)	\
	((db)->db_level > 0 || dmu_ot[(db)->db_dnode->dn_type].ot_metadata)

#define	DBUF_GET_BUFC_TYPE(db)	\
	(DBUF_IS_METADATA(db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)

#define	DBUF_IS_CACHEABLE(db)						\
	((db)->db_objset->os_primary_cache == ZFS_CACHE_ALL ||		\
	(DBUF_IS_METADATA(db) &&					\
	((db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))

#define	DBUF_IS_L2CACHEABLE(db)						\
	((db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL ||	\
	(DBUF_IS_METADATA(db) &&					\
	((db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA)))

#ifdef ZFS_DEBUG

/*
 * There should be a ## between the string literal and fmt, to make it
 * clear that we're joining two strings together, but gcc does not
 * support that preprocessor token.
 */
#define	dprintf_dbuf(dbuf, fmt, ...) do { \
	if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
	char __db_buf[32]; \
	uint64_t __db_obj = (dbuf)->db.db_object; \
	if (__db_obj == DMU_META_DNODE_OBJECT) \
		(void) strcpy(__db_buf, "mdn"); \
	else \
		(void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
		    (u_longlong_t)__db_obj); \
	dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
	    "obj=%s lvl=%u blkid=%lld " fmt, \
	    __db_buf, (dbuf)->db_level, \
	    (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
	} \
_NOTE(CONSTCOND) } while (0)

#define	dprintf_dbuf_bp(db, bp, fmt, ...) do {			\
	if (zfs_flags & ZFS_DEBUG_DPRINTF) {			\
	char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP);	\
	sprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp);		\
	dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf);	\
	kmem_free(__blkbuf, BP_SPRINTF_LEN);			\
	} 							\
_NOTE(CONSTCOND) } while (0)

#define	DBUF_VERIFY(db)	dbuf_verify(db)

#else

#define	dprintf_dbuf(db, fmt, ...)
#define	dprintf_dbuf_bp(db, bp, fmt, ...)
#define	DBUF_VERIFY(db)

#endif


#ifdef	__cplusplus
}
#endif

#endif /* _SYS_DBUF_H */