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.
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.
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]
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.
36 #include <sys/zfs_context.h>
37 #include <sys/refcount.h>
38 #include <sys/zrlock.h>
39 #include <sys/multilist.h>
48 * define flags for dbuf_read
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)
59 * The simplified state transition diagram for dbufs looks like:
64 * (alloc)-->UNCACHED CACHED-->EVICTING-->(free)
70 * +--------> NOFILL -------+
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).
76 typedef enum dbuf_states
{
90 * level = 0 means the user data
91 * level = 1 means the single indirect block
97 typedef enum override_states
{
103 typedef struct dbuf_dirty_record
{
104 /* link on our parents dirty list */
105 list_node_t dr_dirty_node
;
107 /* transaction group this data will sync in */
110 /* zio of outstanding write IO */
113 /* pointer back to our dbuf */
114 struct dmu_buf_impl
*dr_dbuf
;
116 /* pointer to next dirty record */
117 struct dbuf_dirty_record
*dr_next
;
119 /* pointer to parent dirty record */
120 struct dbuf_dirty_record
*dr_parent
;
122 /* How much space was changed to dsl_pool_dirty_space() for this? */
123 unsigned int dr_accounted
;
125 /* A copy of the bp that points to us */
129 struct dirty_indirect
{
131 /* protect access to list */
134 /* Our list of dirty children */
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.
145 blkptr_t dr_overridden_by
;
146 override_states_t dr_override_state
;
148 boolean_t dr_nopwrite
;
151 } dbuf_dirty_record_t
;
153 typedef struct dmu_buf_impl
{
155 * The following members are immutable, with the exception of
156 * db.db_data, which is protected by db_mtx.
159 /* the publicly visible structure */
162 /* the objset we belong to */
163 struct objset
*db_objset
;
166 * handle to safely access the dnode we belong to (NULL when evicted)
168 struct dnode_handle
*db_dnode_handle
;
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())
178 struct dmu_buf_impl
*db_parent
;
181 * link for hash table of all dmu_buf_impl_t's
183 struct dmu_buf_impl
*db_hash_next
;
185 /* our block number */
189 * Pointer to the blkptr_t which points to us. May be NULL if we
190 * don't have one yet. (NULL when evicted)
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.
202 /* db_mtx protects the members below */
206 * Current state of the buffer
208 dbuf_states_t db_state
;
211 * Refcount accessed by dmu_buf_{hold,rele}.
212 * If nonzero, the buffer can't be destroyed.
213 * Protected by db_mtx.
217 /* buffer holding our data */
220 kcondvar_t db_changed
;
221 dbuf_dirty_record_t
*db_data_pending
;
223 /* pointer to most recent dirty record for this buffer */
224 dbuf_dirty_record_t
*db_last_dirty
;
227 * Our link on the owner dnodes's dn_dbufs list.
228 * Protected by its dn_dbufs_mtx.
233 * Link in dbuf_cache.
235 multilist_node_t db_cache_link
;
237 /* Data which is unique to data (leaf) blocks: */
239 /* User callback information. */
240 dmu_buf_user_t
*db_user
;
243 * Evict user data as soon as the dirty and reference
246 uint8_t db_user_immediate_evict
;
249 * This block was freed while a read or write was
252 uint8_t db_freed_in_flight
;
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.
259 uint8_t db_pending_evict
;
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
];
273 uint64_t dbuf_whichblock(struct dnode
*di
, int64_t level
, uint64_t offset
);
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
);
280 void dbuf_rm_spill(struct dnode
*dn
, dmu_tx_t
*tx
);
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
,
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
);
289 void dbuf_prefetch(struct dnode
*dn
, int64_t level
, uint64_t blkid
,
290 zio_priority_t prio
, arc_flags_t aflags
);
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
);
297 void dbuf_rele(dmu_buf_impl_t
*db
, void *tag
);
298 void dbuf_rele_and_unlock(dmu_buf_impl_t
*db
, void *tag
);
300 dmu_buf_impl_t
*dbuf_find(struct objset
*os
, uint64_t object
, uint8_t level
,
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
);
314 void dbuf_destroy(dmu_buf_impl_t
*db
);
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
);
321 void dbuf_free_range(struct dnode
*dn
, uint64_t start
, uint64_t end
,
324 void dbuf_new_size(dmu_buf_impl_t
*db
, int size
, dmu_tx_t
*tx
);
326 #define DB_DNODE(_db) ((_db)->db_dnode_handle->dnh_dnode)
327 #define DB_DNODE_LOCK(_db) ((_db)->db_dnode_handle->dnh_zrlock)
328 #define DB_DNODE_ENTER(_db) (zrl_add(&DB_DNODE_LOCK(_db)))
329 #define DB_DNODE_EXIT(_db) (zrl_remove(&DB_DNODE_LOCK(_db)))
330 #define DB_DNODE_HELD(_db) (!zrl_is_zero(&DB_DNODE_LOCK(_db)))
332 void dbuf_init(void);
333 void dbuf_fini(void);
335 boolean_t
dbuf_is_metadata(dmu_buf_impl_t
*db
);
337 #define DBUF_GET_BUFC_TYPE(_db) \
338 (dbuf_is_metadata(_db) ? ARC_BUFC_METADATA : ARC_BUFC_DATA)
340 #define DBUF_IS_CACHEABLE(_db) \
341 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_ALL || \
342 (dbuf_is_metadata(_db) && \
343 ((_db)->db_objset->os_primary_cache == ZFS_CACHE_METADATA)))
345 #define DBUF_IS_L2CACHEABLE(_db) \
346 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_ALL || \
347 (dbuf_is_metadata(_db) && \
348 ((_db)->db_objset->os_secondary_cache == ZFS_CACHE_METADATA)))
353 * There should be a ## between the string literal and fmt, to make it
354 * clear that we're joining two strings together, but gcc does not
355 * support that preprocessor token.
357 #define dprintf_dbuf(dbuf, fmt, ...) do { \
358 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
360 uint64_t __db_obj = (dbuf)->db.db_object; \
361 if (__db_obj == DMU_META_DNODE_OBJECT) \
362 (void) strcpy(__db_buf, "mdn"); \
364 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
365 (u_longlong_t)__db_obj); \
366 dprintf_ds((dbuf)->db_objset->os_dsl_dataset, \
367 "obj=%s lvl=%u blkid=%lld " fmt, \
368 __db_buf, (dbuf)->db_level, \
369 (u_longlong_t)(dbuf)->db_blkid, __VA_ARGS__); \
371 _NOTE(CONSTCOND) } while (0)
373 #define dprintf_dbuf_bp(db, bp, fmt, ...) do { \
374 if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
375 char *__blkbuf = kmem_alloc(BP_SPRINTF_LEN, KM_SLEEP); \
376 snprintf_blkptr(__blkbuf, BP_SPRINTF_LEN, bp); \
377 dprintf_dbuf(db, fmt " %s\n", __VA_ARGS__, __blkbuf); \
378 kmem_free(__blkbuf, BP_SPRINTF_LEN); \
380 _NOTE(CONSTCOND) } while (0)
382 #define DBUF_VERIFY(db) dbuf_verify(db)
386 #define dprintf_dbuf(db, fmt, ...)
387 #define dprintf_dbuf_bp(db, bp, fmt, ...)
388 #define DBUF_VERIFY(db)
397 #endif /* _SYS_DBUF_H */