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 /*
23 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
24 * Copyright (c) 2011, 2014 by Delphix. All rights reserved.
25 * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
26 * Copyright (c) 2012, Joyent, Inc. All rights reserved.
27 * Copyright 2013 DEY Storage Systems, Inc.
28 * Copyright 2014 HybridCluster. All rights reserved.
29 * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
30 * Copyright 2013 Saso Kiselkov. All rights reserved.
31 * Copyright (c) 2014 Integros [integros.com]
32 */
33
34 /* Portions Copyright 2010 Robert Milkowski */
35
36 #ifndef _SYS_DMU_H
37 #define _SYS_DMU_H
38
39 /*
40 * This file describes the interface that the DMU provides for its
41 * consumers.
42 *
43 * The DMU also interacts with the SPA. That interface is described in
44 * dmu_spa.h.
45 */
46
47 #include <sys/zfs_context.h>
48 #include <sys/inttypes.h>
49 #include <sys/cred.h>
50 #include <sys/fs/zfs.h>
51 #include <sys/zio_priority.h>
52
53 #ifdef __cplusplus
54 extern "C" {
55 #endif
56
57 struct uio;
58 struct xuio;
59 struct page;
60 struct vnode;
61 struct spa;
62 struct zilog;
63 struct zio;
64 struct blkptr;
65 struct zap_cursor;
66 struct dsl_dataset;
67 struct dsl_pool;
68 struct dnode;
69 struct drr_begin;
70 struct drr_end;
71 struct zbookmark_phys;
72 struct spa;
73 struct nvlist;
74 struct arc_buf;
75 struct zio_prop;
76 struct sa_handle;
77
78 typedef struct objset objset_t;
79 typedef struct dmu_tx dmu_tx_t;
80 typedef struct dsl_dir dsl_dir_t;
81
82 typedef enum dmu_object_byteswap {
83 DMU_BSWAP_UINT8,
84 DMU_BSWAP_UINT16,
85 DMU_BSWAP_UINT32,
86 DMU_BSWAP_UINT64,
87 DMU_BSWAP_ZAP,
88 DMU_BSWAP_DNODE,
89 DMU_BSWAP_OBJSET,
90 DMU_BSWAP_ZNODE,
91 DMU_BSWAP_OLDACL,
92 DMU_BSWAP_ACL,
93 /*
94 * Allocating a new byteswap type number makes the on-disk format
95 * incompatible with any other format that uses the same number.
96 *
97 * Data can usually be structured to work with one of the
98 * DMU_BSWAP_UINT* or DMU_BSWAP_ZAP types.
99 */
100 DMU_BSWAP_NUMFUNCS
101 } dmu_object_byteswap_t;
102
103 #define DMU_OT_NEWTYPE 0x80
104 #define DMU_OT_METADATA 0x40
105 #define DMU_OT_BYTESWAP_MASK 0x3f
106
107 /*
108 * Defines a uint8_t object type. Object types specify if the data
109 * in the object is metadata (boolean) and how to byteswap the data
110 * (dmu_object_byteswap_t).
111 */
112 #define DMU_OT(byteswap, metadata) \
113 (DMU_OT_NEWTYPE | \
114 ((metadata) ? DMU_OT_METADATA : 0) | \
115 ((byteswap) & DMU_OT_BYTESWAP_MASK))
116
117 #define DMU_OT_IS_VALID(ot) (((ot) & DMU_OT_NEWTYPE) ? \
118 ((ot) & DMU_OT_BYTESWAP_MASK) < DMU_BSWAP_NUMFUNCS : \
119 (ot) < DMU_OT_NUMTYPES)
120
121 #define DMU_OT_IS_METADATA(ot) (((ot) & DMU_OT_NEWTYPE) ? \
122 ((ot) & DMU_OT_METADATA) : \
123 dmu_ot[(ot)].ot_metadata)
124
125 /*
126 * These object types use bp_fill != 1 for their L0 bp's. Therefore they can't
127 * have their data embedded (i.e. use a BP_IS_EMBEDDED() bp), because bp_fill
128 * is repurposed for embedded BPs.
129 */
130 #define DMU_OT_HAS_FILL(ot) \
131 ((ot) == DMU_OT_DNODE || (ot) == DMU_OT_OBJSET)
132
133 #define DMU_OT_BYTESWAP(ot) (((ot) & DMU_OT_NEWTYPE) ? \
134 ((ot) & DMU_OT_BYTESWAP_MASK) : \
135 dmu_ot[(ot)].ot_byteswap)
136
137 typedef enum dmu_object_type {
138 DMU_OT_NONE,
139 /* general: */
140 DMU_OT_OBJECT_DIRECTORY, /* ZAP */
141 DMU_OT_OBJECT_ARRAY, /* UINT64 */
142 DMU_OT_PACKED_NVLIST, /* UINT8 (XDR by nvlist_pack/unpack) */
143 DMU_OT_PACKED_NVLIST_SIZE, /* UINT64 */
144 DMU_OT_BPOBJ, /* UINT64 */
145 DMU_OT_BPOBJ_HDR, /* UINT64 */
146 /* spa: */
147 DMU_OT_SPACE_MAP_HEADER, /* UINT64 */
148 DMU_OT_SPACE_MAP, /* UINT64 */
149 /* zil: */
150 DMU_OT_INTENT_LOG, /* UINT64 */
151 /* dmu: */
152 DMU_OT_DNODE, /* DNODE */
153 DMU_OT_OBJSET, /* OBJSET */
154 /* dsl: */
155 DMU_OT_DSL_DIR, /* UINT64 */
156 DMU_OT_DSL_DIR_CHILD_MAP, /* ZAP */
157 DMU_OT_DSL_DS_SNAP_MAP, /* ZAP */
158 DMU_OT_DSL_PROPS, /* ZAP */
159 DMU_OT_DSL_DATASET, /* UINT64 */
160 /* zpl: */
161 DMU_OT_ZNODE, /* ZNODE */
162 DMU_OT_OLDACL, /* Old ACL */
163 DMU_OT_PLAIN_FILE_CONTENTS, /* UINT8 */
164 DMU_OT_DIRECTORY_CONTENTS, /* ZAP */
165 DMU_OT_MASTER_NODE, /* ZAP */
166 DMU_OT_UNLINKED_SET, /* ZAP */
167 /* zvol: */
168 DMU_OT_ZVOL, /* UINT8 */
169 DMU_OT_ZVOL_PROP, /* ZAP */
170 /* other; for testing only! */
171 DMU_OT_PLAIN_OTHER, /* UINT8 */
172 DMU_OT_UINT64_OTHER, /* UINT64 */
173 DMU_OT_ZAP_OTHER, /* ZAP */
174 /* new object types: */
175 DMU_OT_ERROR_LOG, /* ZAP */
176 DMU_OT_SPA_HISTORY, /* UINT8 */
177 DMU_OT_SPA_HISTORY_OFFSETS, /* spa_his_phys_t */
178 DMU_OT_POOL_PROPS, /* ZAP */
179 DMU_OT_DSL_PERMS, /* ZAP */
180 DMU_OT_ACL, /* ACL */
181 DMU_OT_SYSACL, /* SYSACL */
182 DMU_OT_FUID, /* FUID table (Packed NVLIST UINT8) */
183 DMU_OT_FUID_SIZE, /* FUID table size UINT64 */
184 DMU_OT_NEXT_CLONES, /* ZAP */
185 DMU_OT_SCAN_QUEUE, /* ZAP */
186 DMU_OT_USERGROUP_USED, /* ZAP */
187 DMU_OT_USERGROUP_QUOTA, /* ZAP */
188 DMU_OT_USERREFS, /* ZAP */
189 DMU_OT_DDT_ZAP, /* ZAP */
190 DMU_OT_DDT_STATS, /* ZAP */
191 DMU_OT_SA, /* System attr */
192 DMU_OT_SA_MASTER_NODE, /* ZAP */
193 DMU_OT_SA_ATTR_REGISTRATION, /* ZAP */
194 DMU_OT_SA_ATTR_LAYOUTS, /* ZAP */
195 DMU_OT_SCAN_XLATE, /* ZAP */
196 DMU_OT_DEDUP, /* fake dedup BP from ddt_bp_create() */
197 DMU_OT_DEADLIST, /* ZAP */
198 DMU_OT_DEADLIST_HDR, /* UINT64 */
199 DMU_OT_DSL_CLONES, /* ZAP */
200 DMU_OT_BPOBJ_SUBOBJ, /* UINT64 */
201 /*
202 * Do not allocate new object types here. Doing so makes the on-disk
203 * format incompatible with any other format that uses the same object
204 * type number.
205 *
206 * When creating an object which does not have one of the above types
207 * use the DMU_OTN_* type with the correct byteswap and metadata
208 * values.
209 *
210 * The DMU_OTN_* types do not have entries in the dmu_ot table,
211 * use the DMU_OT_IS_METDATA() and DMU_OT_BYTESWAP() macros instead
212 * of indexing into dmu_ot directly (this works for both DMU_OT_* types
213 * and DMU_OTN_* types).
214 */
215 DMU_OT_NUMTYPES,
216
217 /*
218 * Names for valid types declared with DMU_OT().
219 */
220 DMU_OTN_UINT8_DATA = DMU_OT(DMU_BSWAP_UINT8, B_FALSE),
221 DMU_OTN_UINT8_METADATA = DMU_OT(DMU_BSWAP_UINT8, B_TRUE),
222 DMU_OTN_UINT16_DATA = DMU_OT(DMU_BSWAP_UINT16, B_FALSE),
223 DMU_OTN_UINT16_METADATA = DMU_OT(DMU_BSWAP_UINT16, B_TRUE),
224 DMU_OTN_UINT32_DATA = DMU_OT(DMU_BSWAP_UINT32, B_FALSE),
225 DMU_OTN_UINT32_METADATA = DMU_OT(DMU_BSWAP_UINT32, B_TRUE),
226 DMU_OTN_UINT64_DATA = DMU_OT(DMU_BSWAP_UINT64, B_FALSE),
227 DMU_OTN_UINT64_METADATA = DMU_OT(DMU_BSWAP_UINT64, B_TRUE),
228 DMU_OTN_ZAP_DATA = DMU_OT(DMU_BSWAP_ZAP, B_FALSE),
229 DMU_OTN_ZAP_METADATA = DMU_OT(DMU_BSWAP_ZAP, B_TRUE),
230 } dmu_object_type_t;
231
232 typedef enum txg_how {
233 TXG_WAIT = 1,
234 TXG_NOWAIT,
235 TXG_WAITED,
236 } txg_how_t;
237
238 void byteswap_uint64_array(void *buf, size_t size);
239 void byteswap_uint32_array(void *buf, size_t size);
240 void byteswap_uint16_array(void *buf, size_t size);
241 void byteswap_uint8_array(void *buf, size_t size);
242 void zap_byteswap(void *buf, size_t size);
243 void zfs_oldacl_byteswap(void *buf, size_t size);
244 void zfs_acl_byteswap(void *buf, size_t size);
245 void zfs_znode_byteswap(void *buf, size_t size);
246
247 #define DS_FIND_SNAPSHOTS (1<<0)
248 #define DS_FIND_CHILDREN (1<<1)
249 #define DS_FIND_SERIALIZE (1<<2)
250
251 /*
252 * The maximum number of bytes that can be accessed as part of one
253 * operation, including metadata.
254 */
255 #define DMU_MAX_ACCESS (32 * 1024 * 1024) /* 32MB */
256 #define DMU_MAX_DELETEBLKCNT (20480) /* ~5MB of indirect blocks */
257
258 #define DMU_USERUSED_OBJECT (-1ULL)
259 #define DMU_GROUPUSED_OBJECT (-2ULL)
260
261 /*
262 * artificial blkids for bonus buffer and spill blocks
263 */
264 #define DMU_BONUS_BLKID (-1ULL)
265 #define DMU_SPILL_BLKID (-2ULL)
266 /*
267 * Public routines to create, destroy, open, and close objsets.
268 */
269 int dmu_objset_hold(const char *name, void *tag, objset_t **osp);
270 int dmu_objset_own(const char *name, dmu_objset_type_t type,
271 boolean_t readonly, void *tag, objset_t **osp);
272 void dmu_objset_rele(objset_t *os, void *tag);
273 void dmu_objset_disown(objset_t *os, void *tag);
274 int dmu_objset_open_ds(struct dsl_dataset *ds, objset_t **osp);
275
276 void dmu_objset_evict_dbufs(objset_t *os);
277 int dmu_objset_create(const char *name, dmu_objset_type_t type, uint64_t flags,
278 void (*func)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx), void *arg);
279 int dmu_objset_clone(const char *name, const char *origin);
280 int dsl_destroy_snapshots_nvl(struct nvlist *snaps, boolean_t defer,
281 struct nvlist *errlist);
282 int dmu_objset_snapshot_one(const char *fsname, const char *snapname);
283 int dmu_objset_snapshot_tmp(const char *, const char *, int);
284 int dmu_objset_find(char *name, int func(const char *, void *), void *arg,
285 int flags);
286 void dmu_objset_byteswap(void *buf, size_t size);
287 int dsl_dataset_rename_snapshot(const char *fsname,
288 const char *oldsnapname, const char *newsnapname, boolean_t recursive);
289
290 typedef struct dmu_buf {
291 uint64_t db_object; /* object that this buffer is part of */
292 uint64_t db_offset; /* byte offset in this object */
293 uint64_t db_size; /* size of buffer in bytes */
294 void *db_data; /* data in buffer */
295 } dmu_buf_t;
296
297 /*
298 * The names of zap entries in the DIRECTORY_OBJECT of the MOS.
299 */
300 #define DMU_POOL_DIRECTORY_OBJECT 1
301 #define DMU_POOL_CONFIG "config"
302 #define DMU_POOL_FEATURES_FOR_WRITE "features_for_write"
303 #define DMU_POOL_FEATURES_FOR_READ "features_for_read"
304 #define DMU_POOL_FEATURE_DESCRIPTIONS "feature_descriptions"
305 #define DMU_POOL_FEATURE_ENABLED_TXG "feature_enabled_txg"
306 #define DMU_POOL_ROOT_DATASET "root_dataset"
307 #define DMU_POOL_SYNC_BPOBJ "sync_bplist"
308 #define DMU_POOL_ERRLOG_SCRUB "errlog_scrub"
309 #define DMU_POOL_ERRLOG_LAST "errlog_last"
310 #define DMU_POOL_SPARES "spares"
311 #define DMU_POOL_DEFLATE "deflate"
312 #define DMU_POOL_HISTORY "history"
313 #define DMU_POOL_PROPS "pool_props"
314 #define DMU_POOL_L2CACHE "l2cache"
315 #define DMU_POOL_TMP_USERREFS "tmp_userrefs"
316 #define DMU_POOL_DDT "DDT-%s-%s-%s"
317 #define DMU_POOL_DDT_STATS "DDT-statistics"
318 #define DMU_POOL_CREATION_VERSION "creation_version"
319 #define DMU_POOL_SCAN "scan"
320 #define DMU_POOL_FREE_BPOBJ "free_bpobj"
321 #define DMU_POOL_BPTREE_OBJ "bptree_obj"
322 #define DMU_POOL_EMPTY_BPOBJ "empty_bpobj"
323 #define DMU_POOL_CHECKSUM_SALT "org.illumos:checksum_salt"
324
325 /*
326 * Allocate an object from this objset. The range of object numbers
327 * available is (0, DN_MAX_OBJECT). Object 0 is the meta-dnode.
328 *
329 * The transaction must be assigned to a txg. The newly allocated
330 * object will be "held" in the transaction (ie. you can modify the
331 * newly allocated object in this transaction).
332 *
333 * dmu_object_alloc() chooses an object and returns it in *objectp.
334 *
335 * dmu_object_claim() allocates a specific object number. If that
336 * number is already allocated, it fails and returns EEXIST.
337 *
338 * Return 0 on success, or ENOSPC or EEXIST as specified above.
339 */
340 uint64_t dmu_object_alloc(objset_t *os, dmu_object_type_t ot,
341 int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
342 int dmu_object_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
343 int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
344 int dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
345 int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *txp);
346
347 /*
348 * Free an object from this objset.
349 *
350 * The object's data will be freed as well (ie. you don't need to call
351 * dmu_free(object, 0, -1, tx)).
352 *
353 * The object need not be held in the transaction.
354 *
355 * If there are any holds on this object's buffers (via dmu_buf_hold()),
356 * or tx holds on the object (via dmu_tx_hold_object()), you can not
357 * free it; it fails and returns EBUSY.
358 *
359 * If the object is not allocated, it fails and returns ENOENT.
360 *
361 * Return 0 on success, or EBUSY or ENOENT as specified above.
362 */
363 int dmu_object_free(objset_t *os, uint64_t object, dmu_tx_t *tx);
364
365 /*
366 * Find the next allocated or free object.
367 *
368 * The objectp parameter is in-out. It will be updated to be the next
369 * object which is allocated. Ignore objects which have not been
370 * modified since txg.
371 *
372 * XXX Can only be called on a objset with no dirty data.
373 *
374 * Returns 0 on success, or ENOENT if there are no more objects.
375 */
376 int dmu_object_next(objset_t *os, uint64_t *objectp,
377 boolean_t hole, uint64_t txg);
378
379 /*
380 * Set the data blocksize for an object.
381 *
382 * The object cannot have any blocks allcated beyond the first. If
383 * the first block is allocated already, the new size must be greater
384 * than the current block size. If these conditions are not met,
385 * ENOTSUP will be returned.
386 *
387 * Returns 0 on success, or EBUSY if there are any holds on the object
388 * contents, or ENOTSUP as described above.
389 */
390 int dmu_object_set_blocksize(objset_t *os, uint64_t object, uint64_t size,
391 int ibs, dmu_tx_t *tx);
392
393 /*
394 * Set the checksum property on a dnode. The new checksum algorithm will
395 * apply to all newly written blocks; existing blocks will not be affected.
396 */
397 void dmu_object_set_checksum(objset_t *os, uint64_t object, uint8_t checksum,
398 dmu_tx_t *tx);
399
400 /*
401 * Set the compress property on a dnode. The new compression algorithm will
402 * apply to all newly written blocks; existing blocks will not be affected.
403 */
404 void dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
405 dmu_tx_t *tx);
406
407 void
408 dmu_write_embedded(objset_t *os, uint64_t object, uint64_t offset,
409 void *data, uint8_t etype, uint8_t comp, int uncompressed_size,
410 int compressed_size, int byteorder, dmu_tx_t *tx);
411
412 /*
413 * Decide how to write a block: checksum, compression, number of copies, etc.
414 */
415 #define WP_NOFILL 0x1
416 #define WP_DMU_SYNC 0x2
417 #define WP_SPILL 0x4
418
419 void dmu_write_policy(objset_t *os, struct dnode *dn, int level, int wp,
420 struct zio_prop *zp);
421 /*
422 * The bonus data is accessed more or less like a regular buffer.
423 * You must dmu_bonus_hold() to get the buffer, which will give you a
424 * dmu_buf_t with db_offset==-1ULL, and db_size = the size of the bonus
425 * data. As with any normal buffer, you must call dmu_buf_read() to
426 * read db_data, dmu_buf_will_dirty() before modifying it, and the
427 * object must be held in an assigned transaction before calling
428 * dmu_buf_will_dirty. You may use dmu_buf_set_user() on the bonus
429 * buffer as well. You must release your hold with dmu_buf_rele().
430 *
431 * Returns ENOENT, EIO, or 0.
432 */
433 int dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **);
434 int dmu_bonus_max(void);
435 int dmu_set_bonus(dmu_buf_t *, int, dmu_tx_t *);
436 int dmu_set_bonustype(dmu_buf_t *, dmu_object_type_t, dmu_tx_t *);
437 dmu_object_type_t dmu_get_bonustype(dmu_buf_t *);
438 int dmu_rm_spill(objset_t *, uint64_t, dmu_tx_t *);
439
440 /*
441 * Special spill buffer support used by "SA" framework
442 */
443
444 int dmu_spill_hold_by_bonus(dmu_buf_t *bonus, void *tag, dmu_buf_t **dbp);
445 int dmu_spill_hold_by_dnode(struct dnode *dn, uint32_t flags,
446 void *tag, dmu_buf_t **dbp);
447 int dmu_spill_hold_existing(dmu_buf_t *bonus, void *tag, dmu_buf_t **dbp);
448
449 /*
450 * Obtain the DMU buffer from the specified object which contains the
451 * specified offset. dmu_buf_hold() puts a "hold" on the buffer, so
452 * that it will remain in memory. You must release the hold with
453 * dmu_buf_rele(). You musn't access the dmu_buf_t after releasing your
454 * hold. You must have a hold on any dmu_buf_t* you pass to the DMU.
455 *
456 * You must call dmu_buf_read, dmu_buf_will_dirty, or dmu_buf_will_fill
457 * on the returned buffer before reading or writing the buffer's
458 * db_data. The comments for those routines describe what particular
459 * operations are valid after calling them.
460 *
461 * The object number must be a valid, allocated object number.
462 */
463 int dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
464 void *tag, dmu_buf_t **, int flags);
465
466 /*
467 * Add a reference to a dmu buffer that has already been held via
468 * dmu_buf_hold() in the current context.
469 */
470 void dmu_buf_add_ref(dmu_buf_t *db, void* tag);
471
472 /*
473 * Attempt to add a reference to a dmu buffer that is in an unknown state,
474 * using a pointer that may have been invalidated by eviction processing.
475 * The request will succeed if the passed in dbuf still represents the
476 * same os/object/blkid, is ineligible for eviction, and has at least
477 * one hold by a user other than the syncer.
478 */
479 boolean_t dmu_buf_try_add_ref(dmu_buf_t *, objset_t *os, uint64_t object,
480 uint64_t blkid, void *tag);
481
482 void dmu_buf_rele(dmu_buf_t *db, void *tag);
483 uint64_t dmu_buf_refcount(dmu_buf_t *db);
484
485 /*
486 * dmu_buf_hold_array holds the DMU buffers which contain all bytes in a
487 * range of an object. A pointer to an array of dmu_buf_t*'s is
488 * returned (in *dbpp).
489 *
490 * dmu_buf_rele_array releases the hold on an array of dmu_buf_t*'s, and
491 * frees the array. The hold on the array of buffers MUST be released
492 * with dmu_buf_rele_array. You can NOT release the hold on each buffer
493 * individually with dmu_buf_rele.
494 */
495 int dmu_buf_hold_array_by_bonus(dmu_buf_t *db, uint64_t offset,
496 uint64_t length, boolean_t read, void *tag,
497 int *numbufsp, dmu_buf_t ***dbpp);
498 void dmu_buf_rele_array(dmu_buf_t **, int numbufs, void *tag);
499
500 typedef void dmu_buf_evict_func_t(void *user_ptr);
501
502 /*
503 * A DMU buffer user object may be associated with a dbuf for the
504 * duration of its lifetime. This allows the user of a dbuf (client)
505 * to attach private data to a dbuf (e.g. in-core only data such as a
506 * dnode_children_t, zap_t, or zap_leaf_t) and be optionally notified
507 * when that dbuf has been evicted. Clients typically respond to the
508 * eviction notification by freeing their private data, thus ensuring
509 * the same lifetime for both dbuf and private data.
510 *
511 * The mapping from a dmu_buf_user_t to any client private data is the
512 * client's responsibility. All current consumers of the API with private
513 * data embed a dmu_buf_user_t as the first member of the structure for
514 * their private data. This allows conversions between the two types
515 * with a simple cast. Since the DMU buf user API never needs access
516 * to the private data, other strategies can be employed if necessary
517 * or convenient for the client (e.g. using container_of() to do the
518 * conversion for private data that cannot have the dmu_buf_user_t as
519 * its first member).
520 *
521 * Eviction callbacks are executed without the dbuf mutex held or any
522 * other type of mechanism to guarantee that the dbuf is still available.
523 * For this reason, users must assume the dbuf has already been freed
524 * and not reference the dbuf from the callback context.
525 *
526 * Users requesting "immediate eviction" are notified as soon as the dbuf
527 * is only referenced by dirty records (dirties == holds). Otherwise the
528 * notification occurs after eviction processing for the dbuf begins.
529 */
530 typedef struct dmu_buf_user {
531 /*
532 * Asynchronous user eviction callback state.
533 */
534 taskq_ent_t dbu_tqent;
535
536 /*
537 * This instance's eviction function pointers.
538 *
539 * dbu_evict_func_prep is called synchronously while dbu_evict_func
540 * is executed asynchronously on a taskq.
541 */
542 dmu_buf_evict_func_t *dbu_evict_func_prep;
543 dmu_buf_evict_func_t *dbu_evict_func;
544 #ifdef ZFS_DEBUG
545 /*
546 * Pointer to user's dbuf pointer. NULL for clients that do
547 * not associate a dbuf with their user data.
548 *
549 * The dbuf pointer is cleared upon eviction so as to catch
550 * use-after-evict bugs in clients.
551 */
552 dmu_buf_t **dbu_clear_on_evict_dbufp;
553 #endif
554 } dmu_buf_user_t;
555
556 /*
557 * Initialize the given dmu_buf_user_t instance with the eviction function
558 * evict_func, to be called when the user is evicted.
559 *
560 * NOTE: This function should only be called once on a given dmu_buf_user_t.
561 * To allow enforcement of this, dbu must already be zeroed on entry.
562 */
563 #ifdef __lint
564 /* Very ugly, but it beats issuing suppression directives in many Makefiles. */
565 extern void
566 dmu_buf_init_user(dmu_buf_user_t *dbu, dmu_buf_evict_func_t *evict_func_prep,
567 dmu_buf_evict_func_t *evict_func, dmu_buf_t **clear_on_evict_dbufp);
568 #else /* __lint */
569 inline void
570 dmu_buf_init_user(dmu_buf_user_t *dbu, dmu_buf_evict_func_t *evict_func_prep,
571 dmu_buf_evict_func_t *evict_func, dmu_buf_t **clear_on_evict_dbufp)
572 {
573 ASSERT(dbu->dbu_evict_func_prep == NULL);
574 ASSERT(dbu->dbu_evict_func == NULL);
575 ASSERT(evict_func != NULL);
576 dbu->dbu_evict_func_prep = evict_func_prep;
577 dbu->dbu_evict_func = evict_func;
578 #ifdef ZFS_DEBUG
579 dbu->dbu_clear_on_evict_dbufp = clear_on_evict_dbufp;
580 #endif
581 }
582 #endif /* __lint */
583
584 /*
585 * Attach user data to a dbuf and mark it for normal (when the dbuf's
586 * data is cleared or its reference count goes to zero) eviction processing.
587 *
588 * Returns NULL on success, or the existing user if another user currently
589 * owns the buffer.
590 */
591 void *dmu_buf_set_user(dmu_buf_t *db, dmu_buf_user_t *user);
592
593 /*
594 * Attach user data to a dbuf and mark it for immediate (its dirty and
595 * reference counts are equal) eviction processing.
596 *
597 * Returns NULL on success, or the existing user if another user currently
598 * owns the buffer.
599 */
600 void *dmu_buf_set_user_ie(dmu_buf_t *db, dmu_buf_user_t *user);
601
602 /*
603 * Replace the current user of a dbuf.
604 *
605 * If given the current user of a dbuf, replaces the dbuf's user with
606 * "new_user" and returns the user data pointer that was replaced.
607 * Otherwise returns the current, and unmodified, dbuf user pointer.
608 */
609 void *dmu_buf_replace_user(dmu_buf_t *db,
610 dmu_buf_user_t *old_user, dmu_buf_user_t *new_user);
611
612 /*
613 * Remove the specified user data for a DMU buffer.
614 *
615 * Returns the user that was removed on success, or the current user if
616 * another user currently owns the buffer.
617 */
618 void *dmu_buf_remove_user(dmu_buf_t *db, dmu_buf_user_t *user);
619
620 /*
621 * Returns the user data (dmu_buf_user_t *) associated with this dbuf.
622 */
623 void *dmu_buf_get_user(dmu_buf_t *db);
624
625 /* Block until any in-progress dmu buf user evictions complete. */
626 void dmu_buf_user_evict_wait(void);
627
628 /*
629 * Returns the blkptr associated with this dbuf, or NULL if not set.
630 */
631 struct blkptr *dmu_buf_get_blkptr(dmu_buf_t *db);
632
633 /*
634 * Indicate that you are going to modify the buffer's data (db_data).
635 *
636 * The transaction (tx) must be assigned to a txg (ie. you've called
637 * dmu_tx_assign()). The buffer's object must be held in the tx
638 * (ie. you've called dmu_tx_hold_object(tx, db->db_object)).
639 */
640 void dmu_buf_will_dirty(dmu_buf_t *db, dmu_tx_t *tx);
641
642 /*
643 * Tells if the given dbuf is freeable.
644 */
645 boolean_t dmu_buf_freeable(dmu_buf_t *);
646
647 /*
648 * You must create a transaction, then hold the objects which you will
649 * (or might) modify as part of this transaction. Then you must assign
650 * the transaction to a transaction group. Once the transaction has
651 * been assigned, you can modify buffers which belong to held objects as
652 * part of this transaction. You can't modify buffers before the
653 * transaction has been assigned; you can't modify buffers which don't
654 * belong to objects which this transaction holds; you can't hold
655 * objects once the transaction has been assigned. You may hold an
656 * object which you are going to free (with dmu_object_free()), but you
657 * don't have to.
658 *
659 * You can abort the transaction before it has been assigned.
660 *
661 * Note that you may hold buffers (with dmu_buf_hold) at any time,
662 * regardless of transaction state.
663 */
664
665 #define DMU_NEW_OBJECT (-1ULL)
666 #define DMU_OBJECT_END (-1ULL)
667
668 dmu_tx_t *dmu_tx_create(objset_t *os);
669 void dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len);
670 void dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off,
671 uint64_t len);
672 void dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, const char *name);
673 void dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object);
674 void dmu_tx_hold_spill(dmu_tx_t *tx, uint64_t object);
675 void dmu_tx_hold_sa(dmu_tx_t *tx, struct sa_handle *hdl, boolean_t may_grow);
676 void dmu_tx_hold_sa_create(dmu_tx_t *tx, int total_size);
677 void dmu_tx_abort(dmu_tx_t *tx);
678 int dmu_tx_assign(dmu_tx_t *tx, enum txg_how txg_how);
679 void dmu_tx_wait(dmu_tx_t *tx);
680 void dmu_tx_commit(dmu_tx_t *tx);
681 void dmu_tx_mark_netfree(dmu_tx_t *tx);
682
683 /*
684 * To register a commit callback, dmu_tx_callback_register() must be called.
685 *
686 * dcb_data is a pointer to caller private data that is passed on as a
687 * callback parameter. The caller is responsible for properly allocating and
688 * freeing it.
689 *
690 * When registering a callback, the transaction must be already created, but
691 * it cannot be committed or aborted. It can be assigned to a txg or not.
692 *
693 * The callback will be called after the transaction has been safely written
694 * to stable storage and will also be called if the dmu_tx is aborted.
695 * If there is any error which prevents the transaction from being committed to
696 * disk, the callback will be called with a value of error != 0.
697 */
698 typedef void dmu_tx_callback_func_t(void *dcb_data, int error);
699
700 void dmu_tx_callback_register(dmu_tx_t *tx, dmu_tx_callback_func_t *dcb_func,
701 void *dcb_data);
702
703 /*
704 * Free up the data blocks for a defined range of a file. If size is
705 * -1, the range from offset to end-of-file is freed.
706 */
707 int dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
708 uint64_t size, dmu_tx_t *tx);
709 int dmu_free_long_range(objset_t *os, uint64_t object, uint64_t offset,
710 uint64_t size);
711 int dmu_free_long_object(objset_t *os, uint64_t object);
712
713 /*
714 * Convenience functions.
715 *
716 * Canfail routines will return 0 on success, or an errno if there is a
717 * nonrecoverable I/O error.
718 */
719 #define DMU_READ_PREFETCH 0 /* prefetch */
720 #define DMU_READ_NO_PREFETCH 1 /* don't prefetch */
721 int dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
722 void *buf, uint32_t flags);
723 void dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
724 const void *buf, dmu_tx_t *tx);
725 void dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
726 dmu_tx_t *tx);
727 int dmu_read_uio(objset_t *os, uint64_t object, struct uio *uio, uint64_t size);
728 int dmu_read_uio_dbuf(dmu_buf_t *zdb, struct uio *uio, uint64_t size);
729 int dmu_write_uio(objset_t *os, uint64_t object, struct uio *uio, uint64_t size,
730 dmu_tx_t *tx);
731 int dmu_write_uio_dbuf(dmu_buf_t *zdb, struct uio *uio, uint64_t size,
732 dmu_tx_t *tx);
733 int dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset,
734 uint64_t size, struct page *pp, dmu_tx_t *tx);
735 struct arc_buf *dmu_request_arcbuf(dmu_buf_t *handle, int size);
736 void dmu_return_arcbuf(struct arc_buf *buf);
737 void dmu_assign_arcbuf(dmu_buf_t *handle, uint64_t offset, struct arc_buf *buf,
738 dmu_tx_t *tx);
739 int dmu_xuio_init(struct xuio *uio, int niov);
740 void dmu_xuio_fini(struct xuio *uio);
741 int dmu_xuio_add(struct xuio *uio, struct arc_buf *abuf, offset_t off,
742 size_t n);
743 int dmu_xuio_cnt(struct xuio *uio);
744 struct arc_buf *dmu_xuio_arcbuf(struct xuio *uio, int i);
745 void dmu_xuio_clear(struct xuio *uio, int i);
746 void xuio_stat_wbuf_copied();
747 void xuio_stat_wbuf_nocopy();
748
749 extern boolean_t zfs_prefetch_disable;
750 extern int zfs_max_recordsize;
751
752 /*
753 * Asynchronously try to read in the data.
754 */
755 void dmu_prefetch(objset_t *os, uint64_t object, int64_t level, uint64_t offset,
756 uint64_t len, enum zio_priority pri);
757
758 typedef struct dmu_object_info {
759 /* All sizes are in bytes unless otherwise indicated. */
760 uint32_t doi_data_block_size;
761 uint32_t doi_metadata_block_size;
762 dmu_object_type_t doi_type;
763 dmu_object_type_t doi_bonus_type;
764 uint64_t doi_bonus_size;
765 uint8_t doi_indirection; /* 2 = dnode->indirect->data */
766 uint8_t doi_checksum;
767 uint8_t doi_compress;
768 uint8_t doi_nblkptr;
769 uint8_t doi_pad[4];
770 uint64_t doi_physical_blocks_512; /* data + metadata, 512b blks */
771 uint64_t doi_max_offset;
772 uint64_t doi_fill_count; /* number of non-empty blocks */
773 } dmu_object_info_t;
774
775 typedef void arc_byteswap_func_t(void *buf, size_t size);
776
777 typedef struct dmu_object_type_info {
778 dmu_object_byteswap_t ot_byteswap;
779 boolean_t ot_metadata;
780 char *ot_name;
781 } dmu_object_type_info_t;
782
783 typedef struct dmu_object_byteswap_info {
784 arc_byteswap_func_t *ob_func;
785 char *ob_name;
786 } dmu_object_byteswap_info_t;
787
788 extern const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES];
789 extern const dmu_object_byteswap_info_t dmu_ot_byteswap[DMU_BSWAP_NUMFUNCS];
790
791 /*
792 * Get information on a DMU object.
793 *
794 * Return 0 on success or ENOENT if object is not allocated.
795 *
796 * If doi is NULL, just indicates whether the object exists.
797 */
798 int dmu_object_info(objset_t *os, uint64_t object, dmu_object_info_t *doi);
799 /* Like dmu_object_info, but faster if you have a held dnode in hand. */
800 void dmu_object_info_from_dnode(struct dnode *dn, dmu_object_info_t *doi);
801 /* Like dmu_object_info, but faster if you have a held dbuf in hand. */
802 void dmu_object_info_from_db(dmu_buf_t *db, dmu_object_info_t *doi);
803 /*
804 * Like dmu_object_info_from_db, but faster still when you only care about
805 * the size. This is specifically optimized for zfs_getattr().
806 */
807 void dmu_object_size_from_db(dmu_buf_t *db, uint32_t *blksize,
808 u_longlong_t *nblk512);
809
810 typedef struct dmu_objset_stats {
811 uint64_t dds_num_clones; /* number of clones of this */
812 uint64_t dds_creation_txg;
813 uint64_t dds_guid;
814 dmu_objset_type_t dds_type;
815 uint8_t dds_is_snapshot;
816 uint8_t dds_inconsistent;
817 char dds_origin[MAXNAMELEN];
818 } dmu_objset_stats_t;
819
820 /*
821 * Get stats on a dataset.
822 */
823 void dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat);
824
825 /*
826 * Add entries to the nvlist for all the objset's properties. See
827 * zfs_prop_table[] and zfs(1m) for details on the properties.
828 */
829 void dmu_objset_stats(objset_t *os, struct nvlist *nv);
830
831 /*
832 * Get the space usage statistics for statvfs().
833 *
834 * refdbytes is the amount of space "referenced" by this objset.
835 * availbytes is the amount of space available to this objset, taking
836 * into account quotas & reservations, assuming that no other objsets
837 * use the space first. These values correspond to the 'referenced' and
838 * 'available' properties, described in the zfs(1m) manpage.
839 *
840 * usedobjs and availobjs are the number of objects currently allocated,
841 * and available.
842 */
843 void dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
844 uint64_t *usedobjsp, uint64_t *availobjsp);
845
846 /*
847 * The fsid_guid is a 56-bit ID that can change to avoid collisions.
848 * (Contrast with the ds_guid which is a 64-bit ID that will never
849 * change, so there is a small probability that it will collide.)
850 */
851 uint64_t dmu_objset_fsid_guid(objset_t *os);
852
853 /*
854 * Get the [cm]time for an objset's snapshot dir
855 */
856 timestruc_t dmu_objset_snap_cmtime(objset_t *os);
857
858 int dmu_objset_is_snapshot(objset_t *os);
859
860 extern struct spa *dmu_objset_spa(objset_t *os);
861 extern struct zilog *dmu_objset_zil(objset_t *os);
862 extern struct dsl_pool *dmu_objset_pool(objset_t *os);
863 extern struct dsl_dataset *dmu_objset_ds(objset_t *os);
864 extern void dmu_objset_name(objset_t *os, char *buf);
865 extern dmu_objset_type_t dmu_objset_type(objset_t *os);
866 extern uint64_t dmu_objset_id(objset_t *os);
867 extern zfs_sync_type_t dmu_objset_syncprop(objset_t *os);
868 extern zfs_logbias_op_t dmu_objset_logbias(objset_t *os);
869 extern int dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
870 uint64_t *id, uint64_t *offp, boolean_t *case_conflict);
871 extern int dmu_snapshot_realname(objset_t *os, char *name, char *real,
872 int maxlen, boolean_t *conflict);
873 extern int dmu_dir_list_next(objset_t *os, int namelen, char *name,
874 uint64_t *idp, uint64_t *offp);
875
876 typedef int objset_used_cb_t(dmu_object_type_t bonustype,
877 void *bonus, uint64_t *userp, uint64_t *groupp);
878 extern void dmu_objset_register_type(dmu_objset_type_t ost,
879 objset_used_cb_t *cb);
880 extern void dmu_objset_set_user(objset_t *os, void *user_ptr);
881 extern void *dmu_objset_get_user(objset_t *os);
882
883 /*
884 * Return the txg number for the given assigned transaction.
885 */
886 uint64_t dmu_tx_get_txg(dmu_tx_t *tx);
887
888 /*
889 * Synchronous write.
890 * If a parent zio is provided this function initiates a write on the
891 * provided buffer as a child of the parent zio.
892 * In the absence of a parent zio, the write is completed synchronously.
893 * At write completion, blk is filled with the bp of the written block.
894 * Note that while the data covered by this function will be on stable
895 * storage when the write completes this new data does not become a
896 * permanent part of the file until the associated transaction commits.
897 */
898
899 /*
900 * {zfs,zvol,ztest}_get_done() args
901 */
902 typedef struct zgd {
903 struct zilog *zgd_zilog;
904 struct blkptr *zgd_bp;
905 dmu_buf_t *zgd_db;
906 struct rl *zgd_rl;
907 void *zgd_private;
908 } zgd_t;
909
910 typedef void dmu_sync_cb_t(zgd_t *arg, int error);
911 int dmu_sync(struct zio *zio, uint64_t txg, dmu_sync_cb_t *done, zgd_t *zgd);
912
913 /*
914 * Find the next hole or data block in file starting at *off
915 * Return found offset in *off. Return ESRCH for end of file.
916 */
917 int dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole,
918 uint64_t *off);
919
920 /*
921 * Check if a DMU object has any dirty blocks. If so, sync out
922 * all pending transaction groups. Otherwise, this function
923 * does not alter DMU state. This could be improved to only sync
924 * out the necessary transaction groups for this particular
925 * object.
926 */
927 int dmu_object_wait_synced(objset_t *os, uint64_t object);
928
929 /*
930 * Initial setup and final teardown.
931 */
932 extern void dmu_init(void);
933 extern void dmu_fini(void);
934
935 typedef void (*dmu_traverse_cb_t)(objset_t *os, void *arg, struct blkptr *bp,
936 uint64_t object, uint64_t offset, int len);
937 void dmu_traverse_objset(objset_t *os, uint64_t txg_start,
938 dmu_traverse_cb_t cb, void *arg);
939
940 int dmu_diff(const char *tosnap_name, const char *fromsnap_name,
941 struct vnode *vp, offset_t *offp);
942
943 /* CRC64 table */
944 #define ZFS_CRC64_POLY 0xC96C5795D7870F42ULL /* ECMA-182, reflected form */
945 extern uint64_t zfs_crc64_table[256];
946
947 extern int zfs_mdcomp_disable;
948
949 #ifdef __cplusplus
950 }
951 #endif
952
953 #endif /* _SYS_DMU_H */