xref: /titanic_41/usr/src/uts/common/fs/zfs/sys/dmu.h (revision 5aefb6555731130ca4fd295960123d71f2d21fe8)
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  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #ifndef	_SYS_DMU_H
27 #define	_SYS_DMU_H
28 
29 #pragma ident	"%Z%%M%	%I%	%E% SMI"
30 
31 /*
32  * This file describes the interface that the DMU provides for its
33  * consumers.
34  *
35  * The DMU also interacts with the SPA.  That interface is described in
36  * dmu_spa.h.
37  */
38 
39 #include <sys/inttypes.h>
40 #include <sys/types.h>
41 #include <sys/param.h>
42 
43 #ifdef	__cplusplus
44 extern "C" {
45 #endif
46 
47 struct uio;
48 struct vnode;
49 struct spa;
50 struct zilog;
51 struct zio;
52 struct blkptr;
53 struct zap_cursor;
54 struct dsl_dataset;
55 struct dsl_pool;
56 struct dnode;
57 struct drr_begin;
58 struct drr_end;
59 
60 typedef struct objset objset_t;
61 typedef struct dmu_tx dmu_tx_t;
62 typedef struct dsl_dir dsl_dir_t;
63 
64 typedef enum dmu_object_type {
65 	DMU_OT_NONE,
66 	/* general: */
67 	DMU_OT_OBJECT_DIRECTORY,	/* ZAP */
68 	DMU_OT_OBJECT_ARRAY,		/* UINT64 */
69 	DMU_OT_PACKED_NVLIST,		/* UINT8 (XDR by nvlist_pack/unpack) */
70 	DMU_OT_PACKED_NVLIST_SIZE,	/* UINT64 */
71 	DMU_OT_BPLIST,			/* UINT64 */
72 	DMU_OT_BPLIST_HDR,		/* UINT64 */
73 	/* spa: */
74 	DMU_OT_SPACE_MAP_HEADER,	/* UINT64 */
75 	DMU_OT_SPACE_MAP,		/* UINT64 */
76 	/* zil: */
77 	DMU_OT_INTENT_LOG,		/* UINT64 */
78 	/* dmu: */
79 	DMU_OT_DNODE,			/* DNODE */
80 	DMU_OT_OBJSET,			/* OBJSET */
81 	/* dsl: */
82 	DMU_OT_DSL_DIR,			/* UINT64 */
83 	DMU_OT_DSL_DIR_CHILD_MAP,	/* ZAP */
84 	DMU_OT_DSL_DS_SNAP_MAP,		/* ZAP */
85 	DMU_OT_DSL_PROPS,		/* ZAP */
86 	DMU_OT_DSL_DATASET,		/* UINT64 */
87 	/* zpl: */
88 	DMU_OT_ZNODE,			/* ZNODE */
89 	DMU_OT_ACL,			/* ACL */
90 	DMU_OT_PLAIN_FILE_CONTENTS,	/* UINT8 */
91 	DMU_OT_DIRECTORY_CONTENTS,	/* ZAP */
92 	DMU_OT_MASTER_NODE,		/* ZAP */
93 	DMU_OT_DELETE_QUEUE,		/* ZAP */
94 	/* zvol: */
95 	DMU_OT_ZVOL,			/* UINT8 */
96 	DMU_OT_ZVOL_PROP,		/* ZAP */
97 	/* other; for testing only! */
98 	DMU_OT_PLAIN_OTHER,		/* UINT8 */
99 	DMU_OT_UINT64_OTHER,		/* UINT64 */
100 	DMU_OT_ZAP_OTHER,		/* ZAP */
101 	/* new object types: */
102 	DMU_OT_ERROR_LOG,		/* ZAP */
103 
104 	DMU_OT_NUMTYPES
105 } dmu_object_type_t;
106 
107 typedef enum dmu_objset_type {
108 	DMU_OST_NONE,
109 	DMU_OST_META,
110 	DMU_OST_ZFS,
111 	DMU_OST_ZVOL,
112 	DMU_OST_OTHER,			/* For testing only! */
113 	DMU_OST_ANY,			/* Be careful! */
114 	DMU_OST_NUMTYPES
115 } dmu_objset_type_t;
116 
117 void byteswap_uint64_array(void *buf, size_t size);
118 void byteswap_uint32_array(void *buf, size_t size);
119 void byteswap_uint16_array(void *buf, size_t size);
120 void byteswap_uint8_array(void *buf, size_t size);
121 void zap_byteswap(void *buf, size_t size);
122 void zfs_acl_byteswap(void *buf, size_t size);
123 void zfs_znode_byteswap(void *buf, size_t size);
124 
125 #define	DS_MODE_NONE		0	/* invalid, to aid debugging */
126 #define	DS_MODE_STANDARD	1	/* normal access, no special needs */
127 #define	DS_MODE_PRIMARY		2	/* the "main" access, e.g. a mount */
128 #define	DS_MODE_EXCLUSIVE	3	/* exclusive access, e.g. to destroy */
129 #define	DS_MODE_LEVELS		4
130 #define	DS_MODE_LEVEL(x)	((x) & (DS_MODE_LEVELS - 1))
131 #define	DS_MODE_READONLY	0x8
132 #define	DS_MODE_IS_READONLY(x)	((x) & DS_MODE_READONLY)
133 #define	DS_MODE_RESTORE		0x10
134 #define	DS_MODE_IS_RESTORE(x)	((x) & DS_MODE_RESTORE)
135 
136 #define	DS_FIND_SNAPSHOTS	0x01
137 
138 /*
139  * The maximum number of bytes that can be accessed as part of one
140  * operation, including metadata.
141  */
142 #define	DMU_MAX_ACCESS (10<<20) /* 10MB */
143 
144 /*
145  * Public routines to create, destroy, open, and close objsets.
146  */
147 int dmu_objset_open(const char *name, dmu_objset_type_t type, int mode,
148     objset_t **osp);
149 void dmu_objset_close(objset_t *os);
150 void dmu_objset_evict_dbufs(objset_t *os);
151 int dmu_objset_create(const char *name, dmu_objset_type_t type,
152     objset_t *clone_parent,
153     void (*func)(objset_t *os, void *arg, dmu_tx_t *tx), void *arg);
154 int dmu_objset_destroy(const char *name);
155 int dmu_objset_rollback(const char *name);
156 int dmu_objset_rename(const char *name, const char *newname);
157 void dmu_objset_set_quota(objset_t *os, uint64_t quota);
158 uint64_t dmu_objset_get_quota(objset_t *os);
159 int dmu_objset_request_reservation(objset_t *os, uint64_t reservation);
160 void dmu_objset_find(char *name, void func(char *, void *), void *arg,
161     int flags);
162 void dmu_objset_byteswap(void *buf, size_t size);
163 
164 typedef struct dmu_buf {
165 	uint64_t db_object;		/* object that this buffer is part of */
166 	uint64_t db_offset;		/* byte offset in this object */
167 	uint64_t db_size;		/* size of buffer in bytes */
168 	void *db_data;			/* data in buffer */
169 } dmu_buf_t;
170 
171 typedef void dmu_buf_evict_func_t(struct dmu_buf *db, void *user_ptr);
172 
173 /*
174  * Callback function to perform byte swapping on a block.
175  */
176 typedef void dmu_byteswap_func_t(void *buf, size_t size);
177 
178 #define	DMU_POOL_DIRECTORY_OBJECT	1
179 #define	DMU_POOL_CONFIG			"config"
180 #define	DMU_POOL_ROOT_DATASET		"root_dataset"
181 #define	DMU_POOL_SYNC_BPLIST		"sync_bplist"
182 #define	DMU_POOL_ERRLOG_SCRUB		"errlog_scrub"
183 #define	DMU_POOL_ERRLOG_LAST		"errlog_last"
184 
185 /*
186  * Allocate an object from this objset.  The range of object numbers
187  * available is (0, DN_MAX_OBJECT).  Object 0 is the meta-dnode.
188  *
189  * The transaction must be assigned to a txg.  The newly allocated
190  * object will be "held" in the transaction (ie. you can modify the
191  * newly allocated object in this transaction).
192  *
193  * dmu_object_alloc() chooses an object and returns it in *objectp.
194  *
195  * dmu_object_claim() allocates a specific object number.  If that
196  * number is already allocated, it fails and returns EEXIST.
197  *
198  * Return 0 on success, or ENOSPC or EEXIST as specified above.
199  */
200 uint64_t dmu_object_alloc(objset_t *os, dmu_object_type_t ot,
201     int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
202 int dmu_object_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
203     int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
204 int dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
205     int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
206 
207 /*
208  * Free an object from this objset.
209  *
210  * The object's data will be freed as well (ie. you don't need to call
211  * dmu_free(object, 0, -1, tx)).
212  *
213  * The object need not be held in the transaction.
214  *
215  * If there are any holds on this object's buffers (via dmu_buf_hold()),
216  * or tx holds on the object (via dmu_tx_hold_object()), you can not
217  * free it; it fails and returns EBUSY.
218  *
219  * If the object is not allocated, it fails and returns ENOENT.
220  *
221  * Return 0 on success, or EBUSY or ENOENT as specified above.
222  */
223 int dmu_object_free(objset_t *os, uint64_t object, dmu_tx_t *tx);
224 
225 /*
226  * Find the next allocated or free object.
227  *
228  * The objectp parameter is in-out.  It will be updated to be the next
229  * object which is allocated.
230  *
231  * XXX Can only be called on a objset with no dirty data.
232  *
233  * Returns 0 on success, or ENOENT if there are no more objects.
234  */
235 int dmu_object_next(objset_t *os, uint64_t *objectp, boolean_t hole);
236 
237 /*
238  * Set the data blocksize for an object.
239  *
240  * The object cannot have any blocks allcated beyond the first.  If
241  * the first block is allocated already, the new size must be greater
242  * than the current block size.  If these conditions are not met,
243  * ENOTSUP will be returned.
244  *
245  * Returns 0 on success, or EBUSY if there are any holds on the object
246  * contents, or ENOTSUP as described above.
247  */
248 int dmu_object_set_blocksize(objset_t *os, uint64_t object, uint64_t size,
249     int ibs, dmu_tx_t *tx);
250 
251 /*
252  * Set the checksum property on a dnode.  The new checksum algorithm will
253  * apply to all newly written blocks; existing blocks will not be affected.
254  */
255 void dmu_object_set_checksum(objset_t *os, uint64_t object, uint8_t checksum,
256     dmu_tx_t *tx);
257 
258 /*
259  * Set the compress property on a dnode.  The new compression algorithm will
260  * apply to all newly written blocks; existing blocks will not be affected.
261  */
262 void dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
263     dmu_tx_t *tx);
264 
265 /*
266  * The bonus data is accessed more or less like a regular buffer.
267  * You must dmu_bonus_hold() to get the buffer, which will give you a
268  * dmu_buf_t with db_offset==-1ULL, and db_size = the size of the bonus
269  * data.  As with any normal buffer, you must call dmu_buf_read() to
270  * read db_data, dmu_buf_will_dirty() before modifying it, and the
271  * object must be held in an assigned transaction before calling
272  * dmu_buf_will_dirty.  You may use dmu_buf_set_user() on the bonus
273  * buffer as well.  You must release your hold with dmu_buf_rele().
274  */
275 int dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **);
276 int dmu_bonus_max(void);
277 
278 /*
279  * Obtain the DMU buffer from the specified object which contains the
280  * specified offset.  dmu_buf_hold() puts a "hold" on the buffer, so
281  * that it will remain in memory.  You must release the hold with
282  * dmu_buf_rele().  You musn't access the dmu_buf_t after releasing your
283  * hold.  You must have a hold on any dmu_buf_t* you pass to the DMU.
284  *
285  * You must call dmu_buf_read, dmu_buf_will_dirty, or dmu_buf_will_fill
286  * on the returned buffer before reading or writing the buffer's
287  * db_data.  The comments for those routines describe what particular
288  * operations are valid after calling them.
289  *
290  * The object number must be a valid, allocated object number.
291  */
292 int dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
293     void *tag, dmu_buf_t **);
294 void dmu_buf_add_ref(dmu_buf_t *db, void* tag);
295 void dmu_buf_rele(dmu_buf_t *db, void *tag);
296 uint64_t dmu_buf_refcount(dmu_buf_t *db);
297 
298 /*
299  * dmu_buf_hold_array holds the DMU buffers which contain all bytes in a
300  * range of an object.  A pointer to an array of dmu_buf_t*'s is
301  * returned (in *dbpp).
302  *
303  * dmu_buf_rele_array releases the hold on an array of dmu_buf_t*'s, and
304  * frees the array.  The hold on the array of buffers MUST be released
305  * with dmu_buf_rele_array.  You can NOT release the hold on each buffer
306  * individually with dmu_buf_rele.
307  */
308 int dmu_buf_hold_array(objset_t *os, uint64_t object, uint64_t offset,
309     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp);
310 void dmu_buf_rele_array(dmu_buf_t **, int numbufs, void *tag);
311 
312 /*
313  * Returns NULL on success, or the existing user ptr if it's already
314  * been set.
315  *
316  * user_ptr is for use by the user and can be obtained via dmu_buf_get_user().
317  *
318  * user_data_ptr_ptr should be NULL, or a pointer to a pointer which
319  * will be set to db->db_data when you are allowed to access it.  Note
320  * that db->db_data (the pointer) can change when you do dmu_buf_read(),
321  * dmu_buf_tryupgrade(), dmu_buf_will_dirty(), or dmu_buf_will_fill().
322  * *user_data_ptr_ptr will be set to the new value when it changes.
323  *
324  * If non-NULL, pageout func will be called when this buffer is being
325  * excised from the cache, so that you can clean up the data structure
326  * pointed to by user_ptr.
327  *
328  * dmu_evict_user() will call the pageout func for all buffers in a
329  * objset with a given pageout func.
330  */
331 void *dmu_buf_set_user(dmu_buf_t *db, void *user_ptr, void *user_data_ptr_ptr,
332     dmu_buf_evict_func_t *pageout_func);
333 /*
334  * set_user_ie is the same as set_user, but request immediate eviction
335  * when hold count goes to zero.
336  */
337 void *dmu_buf_set_user_ie(dmu_buf_t *db, void *user_ptr,
338     void *user_data_ptr_ptr, dmu_buf_evict_func_t *pageout_func);
339 void *dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr,
340     void *user_ptr, void *user_data_ptr_ptr,
341     dmu_buf_evict_func_t *pageout_func);
342 void dmu_evict_user(objset_t *os, dmu_buf_evict_func_t *func);
343 
344 void dmu_buf_hold_data(dmu_buf_t *db);
345 void dmu_buf_rele_data(dmu_buf_t *db);
346 
347 /*
348  * Returns the user_ptr set with dmu_buf_set_user(), or NULL if not set.
349  */
350 void *dmu_buf_get_user(dmu_buf_t *db);
351 
352 /*
353  * Indicate that you are going to modify the buffer's data (db_data).
354  *
355  * The transaction (tx) must be assigned to a txg (ie. you've called
356  * dmu_tx_assign()).  The buffer's object must be held in the tx
357  * (ie. you've called dmu_tx_hold_object(tx, db->db_object)).
358  */
359 void dmu_buf_will_dirty(dmu_buf_t *db, dmu_tx_t *tx);
360 
361 /*
362  * You must create a transaction, then hold the objects which you will
363  * (or might) modify as part of this transaction.  Then you must assign
364  * the transaction to a transaction group.  Once the transaction has
365  * been assigned, you can modify buffers which belong to held objects as
366  * part of this transaction.  You can't modify buffers before the
367  * transaction has been assigned; you can't modify buffers which don't
368  * belong to objects which this transaction holds; you can't hold
369  * objects once the transaction has been assigned.  You may hold an
370  * object which you are going to free (with dmu_object_free()), but you
371  * don't have to.
372  *
373  * You can abort the transaction before it has been assigned.
374  *
375  * Note that you may hold buffers (with dmu_buf_hold) at any time,
376  * regardless of transaction state.
377  */
378 
379 #define	DMU_NEW_OBJECT	(-1ULL)
380 #define	DMU_OBJECT_END	(-1ULL)
381 
382 dmu_tx_t *dmu_tx_create(objset_t *os);
383 void dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len);
384 void dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off,
385     uint64_t len);
386 void dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, char *name);
387 void dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object);
388 void dmu_tx_abort(dmu_tx_t *tx);
389 int dmu_tx_assign(dmu_tx_t *tx, uint64_t txg_how);
390 void dmu_tx_commit(dmu_tx_t *tx);
391 
392 /*
393  * Free up the data blocks for a defined range of a file.  If size is
394  * zero, the range from offset to end-of-file is freed.
395  */
396 int dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
397 	uint64_t size, dmu_tx_t *tx);
398 
399 /*
400  * Convenience functions.
401  *
402  * Canfail routines will return 0 on success, or an errno if there is a
403  * nonrecoverable I/O error.
404  */
405 int dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
406 	void *buf);
407 void dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
408 	const void *buf, dmu_tx_t *tx);
409 int dmu_write_uio(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
410     struct uio *uio, dmu_tx_t *tx);
411 
412 /*
413  * Asynchronously try to read in the data.
414  */
415 void dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset,
416     uint64_t len);
417 
418 typedef struct dmu_object_info {
419 	/* All sizes are in bytes. */
420 	uint32_t doi_data_block_size;
421 	uint32_t doi_metadata_block_size;
422 	uint64_t doi_bonus_size;
423 	dmu_object_type_t doi_type;
424 	dmu_object_type_t doi_bonus_type;
425 	uint8_t doi_indirection;		/* 2 = dnode->indirect->data */
426 	uint8_t doi_checksum;
427 	uint8_t doi_compress;
428 	uint8_t doi_pad[5];
429 	/* Values below are number of 512-byte blocks. */
430 	uint64_t doi_physical_blks;		/* data + metadata */
431 	uint64_t doi_max_block_offset;
432 } dmu_object_info_t;
433 
434 typedef struct dmu_object_type_info {
435 	dmu_byteswap_func_t	*ot_byteswap;
436 	boolean_t		ot_metadata;
437 	char			*ot_name;
438 } dmu_object_type_info_t;
439 
440 extern const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES];
441 
442 /*
443  * Get information on a DMU object.
444  *
445  * Return 0 on success or ENOENT if object is not allocated.
446  *
447  * If doi is NULL, just indicates whether the object exists.
448  */
449 int dmu_object_info(objset_t *os, uint64_t object, dmu_object_info_t *doi);
450 void dmu_object_info_from_dnode(struct dnode *dn, dmu_object_info_t *doi);
451 void dmu_object_info_from_db(dmu_buf_t *db, dmu_object_info_t *doi);
452 void dmu_object_size_from_db(dmu_buf_t *db, uint32_t *blksize,
453     u_longlong_t *nblk512);
454 
455 /*
456  * Get the maximum nonzero offset in the object (ie. this offset and all
457  * offsets following are zero).
458  *
459  * XXX Perhaps integrate this with dmu_object_info(), although that
460  * would then have to bring in the indirect blocks.
461  */
462 uint64_t dmu_object_max_nonzero_offset(objset_t *os, uint64_t object);
463 
464 typedef struct dmu_objset_stats {
465 	dmu_objset_type_t dds_type;
466 	uint8_t dds_is_snapshot;
467 	uint8_t dds_pad[3];
468 
469 	uint64_t dds_creation_time;
470 	uint64_t dds_creation_txg;
471 
472 	char dds_clone_of[MAXNAMELEN];
473 
474 	/* How much data is there in this objset? */
475 
476 	/*
477 	 * Space referenced, taking into account pending writes and
478 	 * frees.  Only relavent to filesystems and snapshots (not
479 	 * collections).
480 	 */
481 	uint64_t dds_space_refd;
482 
483 	/*
484 	 * Space "used", taking into account pending writes and frees, and
485 	 * children's reservations (in bytes).  This is the amount of
486 	 * space that will be freed if this and all dependent items are
487 	 * destroyed (eg. child datasets, objsets, and snapshots).  So
488 	 * for snapshots, this is the amount of space unique to this
489 	 * snapshot.
490 	 */
491 	uint64_t dds_space_used;
492 
493 	/*
494 	 * Compressed and uncompressed bytes consumed.  Does not take
495 	 * into account reservations.  Used for computing compression
496 	 * ratio.
497 	 */
498 	uint64_t dds_compressed_bytes;
499 	uint64_t dds_uncompressed_bytes;
500 
501 	/*
502 	 * The ds_fsid_guid is a 56-bit ID that can change to avoid
503 	 * collisions.  The ds_guid is a 64-bit ID that will never
504 	 * change, so there is a small probability that it will collide.
505 	 */
506 	uint64_t dds_fsid_guid;
507 
508 	uint64_t dds_objects_used;	/* number of objects used */
509 	uint64_t dds_objects_avail;	/* number of objects available */
510 
511 	uint64_t dds_num_clones; /* number of clones of this */
512 
513 	/* The dataset's administratively-set quota, in bytes. */
514 	uint64_t dds_quota;
515 
516 	/* The dataset's administratively-set reservation, in bytes */
517 	uint64_t dds_reserved;
518 
519 	/*
520 	 * The amount of additional space that this dataset can consume.
521 	 * Takes into account quotas & reservations.
522 	 * (Assuming that no other datasets consume it first.)
523 	 */
524 	uint64_t dds_available;
525 
526 	/*
527 	 * Used for debugging purposes
528 	 */
529 	uint64_t dds_last_txg;
530 } dmu_objset_stats_t;
531 
532 /*
533  * Get stats on a dataset.
534  */
535 void dmu_objset_stats(objset_t *os, dmu_objset_stats_t *dds);
536 
537 int dmu_objset_is_snapshot(objset_t *os);
538 
539 extern struct spa *dmu_objset_spa(objset_t *os);
540 extern struct zilog *dmu_objset_zil(objset_t *os);
541 extern struct dsl_pool *dmu_objset_pool(objset_t *os);
542 extern struct dsl_dataset *dmu_objset_ds(objset_t *os);
543 extern void dmu_objset_name(objset_t *os, char *buf);
544 extern dmu_objset_type_t dmu_objset_type(objset_t *os);
545 extern uint64_t dmu_objset_id(objset_t *os);
546 extern int dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
547     uint64_t *id, uint64_t *offp);
548 extern int dmu_dir_list_next(objset_t *os, int namelen, char *name,
549     uint64_t *idp, uint64_t *offp);
550 
551 /*
552  * Return the txg number for the given assigned transaction.
553  */
554 uint64_t dmu_tx_get_txg(dmu_tx_t *tx);
555 
556 /*
557  * Synchronous write.
558  * On success returns 0 and fills in the blk pointed at by bp.
559  * Note that while the data covered by this function will be on stable
560  * storage when the function returns this new data does not become a
561  * permanent part of the file until the associated transaction commits.
562  */
563 int dmu_sync(objset_t *os, uint64_t object, uint64_t offset, uint64_t *blkoff,
564     struct blkptr *bp, uint64_t txg);
565 
566 /*
567  * Find the next hole or data block in file starting at *off
568  * Return found offset in *off. Return ESRCH for end of file.
569  */
570 int dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole,
571     uint64_t *off);
572 
573 /*
574  * Initial setup and final teardown.
575  */
576 extern void dmu_init(void);
577 extern void dmu_fini(void);
578 
579 typedef void (*dmu_traverse_cb_t)(objset_t *os, void *arg, struct blkptr *bp,
580     uint64_t object, uint64_t offset, int len);
581 void dmu_traverse_objset(objset_t *os, uint64_t txg_start,
582     dmu_traverse_cb_t cb, void *arg);
583 
584 int dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, struct vnode *vp);
585 int dmu_recvbackup(char *tosnap, struct drr_begin *drrb, uint64_t *sizep,
586     struct vnode *vp, uint64_t voffset);
587 
588 /* CRC64 table */
589 #define	ZFS_CRC64_POLY	0xC96C5795D7870F42ULL	/* ECMA-182, reflected form */
590 extern uint64_t zfs_crc64_table[256];
591 
592 #ifdef	__cplusplus
593 }
594 #endif
595 
596 #endif	/* _SYS_DMU_H */
597