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