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