xref: /illumos-gate/usr/src/uts/common/fs/zfs/sys/dmu.h (revision 10a4fa49f51ed9ae1c857a626de6ce9ebf41661a)
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 struct zbookmark;
60 struct spa;
61 
62 typedef struct objset objset_t;
63 typedef struct dmu_tx dmu_tx_t;
64 typedef struct dsl_dir dsl_dir_t;
65 
66 typedef enum dmu_object_type {
67 	DMU_OT_NONE,
68 	/* general: */
69 	DMU_OT_OBJECT_DIRECTORY,	/* ZAP */
70 	DMU_OT_OBJECT_ARRAY,		/* UINT64 */
71 	DMU_OT_PACKED_NVLIST,		/* UINT8 (XDR by nvlist_pack/unpack) */
72 	DMU_OT_PACKED_NVLIST_SIZE,	/* UINT64 */
73 	DMU_OT_BPLIST,			/* UINT64 */
74 	DMU_OT_BPLIST_HDR,		/* UINT64 */
75 	/* spa: */
76 	DMU_OT_SPACE_MAP_HEADER,	/* UINT64 */
77 	DMU_OT_SPACE_MAP,		/* UINT64 */
78 	/* zil: */
79 	DMU_OT_INTENT_LOG,		/* UINT64 */
80 	/* dmu: */
81 	DMU_OT_DNODE,			/* DNODE */
82 	DMU_OT_OBJSET,			/* OBJSET */
83 	/* dsl: */
84 	DMU_OT_DSL_DIR,			/* UINT64 */
85 	DMU_OT_DSL_DIR_CHILD_MAP,	/* ZAP */
86 	DMU_OT_DSL_DS_SNAP_MAP,		/* ZAP */
87 	DMU_OT_DSL_PROPS,		/* ZAP */
88 	DMU_OT_DSL_DATASET,		/* UINT64 */
89 	/* zpl: */
90 	DMU_OT_ZNODE,			/* ZNODE */
91 	DMU_OT_ACL,			/* ACL */
92 	DMU_OT_PLAIN_FILE_CONTENTS,	/* UINT8 */
93 	DMU_OT_DIRECTORY_CONTENTS,	/* ZAP */
94 	DMU_OT_MASTER_NODE,		/* ZAP */
95 	DMU_OT_DELETE_QUEUE,		/* ZAP */
96 	/* zvol: */
97 	DMU_OT_ZVOL,			/* UINT8 */
98 	DMU_OT_ZVOL_PROP,		/* ZAP */
99 	/* other; for testing only! */
100 	DMU_OT_PLAIN_OTHER,		/* UINT8 */
101 	DMU_OT_UINT64_OTHER,		/* UINT64 */
102 	DMU_OT_ZAP_OTHER,		/* ZAP */
103 	/* new object types: */
104 	DMU_OT_ERROR_LOG,		/* ZAP */
105 
106 	DMU_OT_NUMTYPES
107 } dmu_object_type_t;
108 
109 typedef enum dmu_objset_type {
110 	DMU_OST_NONE,
111 	DMU_OST_META,
112 	DMU_OST_ZFS,
113 	DMU_OST_ZVOL,
114 	DMU_OST_OTHER,			/* For testing only! */
115 	DMU_OST_ANY,			/* Be careful! */
116 	DMU_OST_NUMTYPES
117 } dmu_objset_type_t;
118 
119 void byteswap_uint64_array(void *buf, size_t size);
120 void byteswap_uint32_array(void *buf, size_t size);
121 void byteswap_uint16_array(void *buf, size_t size);
122 void byteswap_uint8_array(void *buf, size_t size);
123 void zap_byteswap(void *buf, size_t size);
124 void zfs_acl_byteswap(void *buf, size_t size);
125 void zfs_znode_byteswap(void *buf, size_t size);
126 
127 #define	DS_MODE_NONE		0	/* invalid, to aid debugging */
128 #define	DS_MODE_STANDARD	1	/* normal access, no special needs */
129 #define	DS_MODE_PRIMARY		2	/* the "main" access, e.g. a mount */
130 #define	DS_MODE_EXCLUSIVE	3	/* exclusive access, e.g. to destroy */
131 #define	DS_MODE_LEVELS		4
132 #define	DS_MODE_LEVEL(x)	((x) & (DS_MODE_LEVELS - 1))
133 #define	DS_MODE_READONLY	0x8
134 #define	DS_MODE_IS_READONLY(x)	((x) & DS_MODE_READONLY)
135 #define	DS_MODE_INCONSISTENT	0x10
136 #define	DS_MODE_IS_INCONSISTENT(x)	((x) & DS_MODE_INCONSISTENT)
137 
138 #define	DS_FIND_SNAPSHOTS	0x01
139 
140 /*
141  * The maximum number of bytes that can be accessed as part of one
142  * operation, including metadata.
143  */
144 #define	DMU_MAX_ACCESS (10<<20) /* 10MB */
145 
146 /*
147  * Public routines to create, destroy, open, and close objsets.
148  */
149 int dmu_objset_open(const char *name, dmu_objset_type_t type, int mode,
150     objset_t **osp);
151 void dmu_objset_close(objset_t *os);
152 int dmu_objset_evict_dbufs(objset_t *os, int try);
153 int dmu_objset_create(const char *name, dmu_objset_type_t type,
154     objset_t *clone_parent,
155     void (*func)(objset_t *os, void *arg, dmu_tx_t *tx), void *arg);
156 int dmu_objset_destroy(const char *name);
157 int dmu_objset_rollback(const char *name);
158 int dmu_objset_rename(const char *name, const char *newname);
159 void dmu_objset_set_quota(objset_t *os, uint64_t quota);
160 uint64_t dmu_objset_get_quota(objset_t *os);
161 int dmu_objset_request_reservation(objset_t *os, uint64_t reservation);
162 void dmu_objset_find(char *name, void func(char *, void *), void *arg,
163     int flags);
164 void dmu_objset_byteswap(void *buf, size_t size);
165 
166 typedef struct dmu_buf {
167 	uint64_t db_object;		/* object that this buffer is part of */
168 	uint64_t db_offset;		/* byte offset in this object */
169 	uint64_t db_size;		/* size of buffer in bytes */
170 	void *db_data;			/* data in buffer */
171 } dmu_buf_t;
172 
173 typedef void dmu_buf_evict_func_t(struct dmu_buf *db, void *user_ptr);
174 
175 /*
176  * Callback function to perform byte swapping on a block.
177  */
178 typedef void dmu_byteswap_func_t(void *buf, size_t size);
179 
180 #define	DMU_POOL_DIRECTORY_OBJECT	1
181 #define	DMU_POOL_CONFIG			"config"
182 #define	DMU_POOL_ROOT_DATASET		"root_dataset"
183 #define	DMU_POOL_SYNC_BPLIST		"sync_bplist"
184 #define	DMU_POOL_ERRLOG_SCRUB		"errlog_scrub"
185 #define	DMU_POOL_ERRLOG_LAST		"errlog_last"
186 
187 /*
188  * Allocate an object from this objset.  The range of object numbers
189  * available is (0, DN_MAX_OBJECT).  Object 0 is the meta-dnode.
190  *
191  * The transaction must be assigned to a txg.  The newly allocated
192  * object will be "held" in the transaction (ie. you can modify the
193  * newly allocated object in this transaction).
194  *
195  * dmu_object_alloc() chooses an object and returns it in *objectp.
196  *
197  * dmu_object_claim() allocates a specific object number.  If that
198  * number is already allocated, it fails and returns EEXIST.
199  *
200  * Return 0 on success, or ENOSPC or EEXIST as specified above.
201  */
202 uint64_t dmu_object_alloc(objset_t *os, 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_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
205     int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
206 int dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
207     int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *tx);
208 
209 /*
210  * Free an object from this objset.
211  *
212  * The object's data will be freed as well (ie. you don't need to call
213  * dmu_free(object, 0, -1, tx)).
214  *
215  * The object need not be held in the transaction.
216  *
217  * If there are any holds on this object's buffers (via dmu_buf_hold()),
218  * or tx holds on the object (via dmu_tx_hold_object()), you can not
219  * free it; it fails and returns EBUSY.
220  *
221  * If the object is not allocated, it fails and returns ENOENT.
222  *
223  * Return 0 on success, or EBUSY or ENOENT as specified above.
224  */
225 int dmu_object_free(objset_t *os, uint64_t object, dmu_tx_t *tx);
226 
227 /*
228  * Find the next allocated or free object.
229  *
230  * The objectp parameter is in-out.  It will be updated to be the next
231  * object which is allocated.
232  *
233  * XXX Can only be called on a objset with no dirty data.
234  *
235  * Returns 0 on success, or ENOENT if there are no more objects.
236  */
237 int dmu_object_next(objset_t *os, uint64_t *objectp, boolean_t hole);
238 
239 /*
240  * Set the data blocksize for an object.
241  *
242  * The object cannot have any blocks allcated beyond the first.  If
243  * the first block is allocated already, the new size must be greater
244  * than the current block size.  If these conditions are not met,
245  * ENOTSUP will be returned.
246  *
247  * Returns 0 on success, or EBUSY if there are any holds on the object
248  * contents, or ENOTSUP as described above.
249  */
250 int dmu_object_set_blocksize(objset_t *os, uint64_t object, uint64_t size,
251     int ibs, dmu_tx_t *tx);
252 
253 /*
254  * Set the checksum property on a dnode.  The new checksum algorithm will
255  * apply to all newly written blocks; existing blocks will not be affected.
256  */
257 void dmu_object_set_checksum(objset_t *os, uint64_t object, uint8_t checksum,
258     dmu_tx_t *tx);
259 
260 /*
261  * Set the compress property on a dnode.  The new compression algorithm will
262  * apply to all newly written blocks; existing blocks will not be affected.
263  */
264 void dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
265     dmu_tx_t *tx);
266 
267 /*
268  * Decide how many copies of a given block we should make.  Can be from
269  * 1 to SPA_DVAS_PER_BP.
270  */
271 int dmu_get_replication_level(struct spa *spa, struct zbookmark *zb,
272     dmu_object_type_t ot);
273 /*
274  * The bonus data is accessed more or less like a regular buffer.
275  * You must dmu_bonus_hold() to get the buffer, which will give you a
276  * dmu_buf_t with db_offset==-1ULL, and db_size = the size of the bonus
277  * data.  As with any normal buffer, you must call dmu_buf_read() to
278  * read db_data, dmu_buf_will_dirty() before modifying it, and the
279  * object must be held in an assigned transaction before calling
280  * dmu_buf_will_dirty.  You may use dmu_buf_set_user() on the bonus
281  * buffer as well.  You must release your hold with dmu_buf_rele().
282  */
283 int dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **);
284 int dmu_bonus_max(void);
285 
286 /*
287  * Obtain the DMU buffer from the specified object which contains the
288  * specified offset.  dmu_buf_hold() puts a "hold" on the buffer, so
289  * that it will remain in memory.  You must release the hold with
290  * dmu_buf_rele().  You musn't access the dmu_buf_t after releasing your
291  * hold.  You must have a hold on any dmu_buf_t* you pass to the DMU.
292  *
293  * You must call dmu_buf_read, dmu_buf_will_dirty, or dmu_buf_will_fill
294  * on the returned buffer before reading or writing the buffer's
295  * db_data.  The comments for those routines describe what particular
296  * operations are valid after calling them.
297  *
298  * The object number must be a valid, allocated object number.
299  */
300 int dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
301     void *tag, dmu_buf_t **);
302 void dmu_buf_add_ref(dmu_buf_t *db, void* tag);
303 void dmu_buf_rele(dmu_buf_t *db, void *tag);
304 uint64_t dmu_buf_refcount(dmu_buf_t *db);
305 
306 /*
307  * dmu_buf_hold_array holds the DMU buffers which contain all bytes in a
308  * range of an object.  A pointer to an array of dmu_buf_t*'s is
309  * returned (in *dbpp).
310  *
311  * dmu_buf_rele_array releases the hold on an array of dmu_buf_t*'s, and
312  * frees the array.  The hold on the array of buffers MUST be released
313  * with dmu_buf_rele_array.  You can NOT release the hold on each buffer
314  * individually with dmu_buf_rele.
315  */
316 int dmu_buf_hold_array(objset_t *os, uint64_t object, uint64_t offset,
317     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp);
318 void dmu_buf_rele_array(dmu_buf_t **, int numbufs, void *tag);
319 
320 /*
321  * Returns NULL on success, or the existing user ptr if it's already
322  * been set.
323  *
324  * user_ptr is for use by the user and can be obtained via dmu_buf_get_user().
325  *
326  * user_data_ptr_ptr should be NULL, or a pointer to a pointer which
327  * will be set to db->db_data when you are allowed to access it.  Note
328  * that db->db_data (the pointer) can change when you do dmu_buf_read(),
329  * dmu_buf_tryupgrade(), dmu_buf_will_dirty(), or dmu_buf_will_fill().
330  * *user_data_ptr_ptr will be set to the new value when it changes.
331  *
332  * If non-NULL, pageout func will be called when this buffer is being
333  * excised from the cache, so that you can clean up the data structure
334  * pointed to by user_ptr.
335  *
336  * dmu_evict_user() will call the pageout func for all buffers in a
337  * objset with a given pageout func.
338  */
339 void *dmu_buf_set_user(dmu_buf_t *db, void *user_ptr, void *user_data_ptr_ptr,
340     dmu_buf_evict_func_t *pageout_func);
341 /*
342  * set_user_ie is the same as set_user, but request immediate eviction
343  * when hold count goes to zero.
344  */
345 void *dmu_buf_set_user_ie(dmu_buf_t *db, void *user_ptr,
346     void *user_data_ptr_ptr, dmu_buf_evict_func_t *pageout_func);
347 void *dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr,
348     void *user_ptr, void *user_data_ptr_ptr,
349     dmu_buf_evict_func_t *pageout_func);
350 void dmu_evict_user(objset_t *os, dmu_buf_evict_func_t *func);
351 
352 void dmu_buf_hold_data(dmu_buf_t *db);
353 void dmu_buf_rele_data(dmu_buf_t *db);
354 
355 /*
356  * Returns the user_ptr set with dmu_buf_set_user(), or NULL if not set.
357  */
358 void *dmu_buf_get_user(dmu_buf_t *db);
359 
360 /*
361  * Indicate that you are going to modify the buffer's data (db_data).
362  *
363  * The transaction (tx) must be assigned to a txg (ie. you've called
364  * dmu_tx_assign()).  The buffer's object must be held in the tx
365  * (ie. you've called dmu_tx_hold_object(tx, db->db_object)).
366  */
367 void dmu_buf_will_dirty(dmu_buf_t *db, dmu_tx_t *tx);
368 
369 /*
370  * You must create a transaction, then hold the objects which you will
371  * (or might) modify as part of this transaction.  Then you must assign
372  * the transaction to a transaction group.  Once the transaction has
373  * been assigned, you can modify buffers which belong to held objects as
374  * part of this transaction.  You can't modify buffers before the
375  * transaction has been assigned; you can't modify buffers which don't
376  * belong to objects which this transaction holds; you can't hold
377  * objects once the transaction has been assigned.  You may hold an
378  * object which you are going to free (with dmu_object_free()), but you
379  * don't have to.
380  *
381  * You can abort the transaction before it has been assigned.
382  *
383  * Note that you may hold buffers (with dmu_buf_hold) at any time,
384  * regardless of transaction state.
385  */
386 
387 #define	DMU_NEW_OBJECT	(-1ULL)
388 #define	DMU_OBJECT_END	(-1ULL)
389 
390 dmu_tx_t *dmu_tx_create(objset_t *os);
391 void dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len);
392 void dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off,
393     uint64_t len);
394 void dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, char *name);
395 void dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object);
396 void dmu_tx_abort(dmu_tx_t *tx);
397 int dmu_tx_assign(dmu_tx_t *tx, uint64_t txg_how);
398 void dmu_tx_commit(dmu_tx_t *tx);
399 
400 /*
401  * Free up the data blocks for a defined range of a file.  If size is
402  * zero, the range from offset to end-of-file is freed.
403  */
404 int dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
405 	uint64_t size, dmu_tx_t *tx);
406 
407 /*
408  * Convenience functions.
409  *
410  * Canfail routines will return 0 on success, or an errno if there is a
411  * nonrecoverable I/O error.
412  */
413 int dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
414 	void *buf);
415 void dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
416 	const void *buf, dmu_tx_t *tx);
417 int dmu_write_uio(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
418     struct uio *uio, dmu_tx_t *tx);
419 
420 /*
421  * Asynchronously try to read in the data.
422  */
423 void dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset,
424     uint64_t len);
425 
426 typedef struct dmu_object_info {
427 	/* All sizes are in bytes. */
428 	uint32_t doi_data_block_size;
429 	uint32_t doi_metadata_block_size;
430 	uint64_t doi_bonus_size;
431 	dmu_object_type_t doi_type;
432 	dmu_object_type_t doi_bonus_type;
433 	uint8_t doi_indirection;		/* 2 = dnode->indirect->data */
434 	uint8_t doi_checksum;
435 	uint8_t doi_compress;
436 	uint8_t doi_pad[5];
437 	/* Values below are number of 512-byte blocks. */
438 	uint64_t doi_physical_blks;		/* data + metadata */
439 	uint64_t doi_max_block_offset;
440 } dmu_object_info_t;
441 
442 typedef struct dmu_object_type_info {
443 	dmu_byteswap_func_t	*ot_byteswap;
444 	boolean_t		ot_metadata;
445 	char			*ot_name;
446 } dmu_object_type_info_t;
447 
448 extern const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES];
449 
450 /*
451  * Get information on a DMU object.
452  *
453  * Return 0 on success or ENOENT if object is not allocated.
454  *
455  * If doi is NULL, just indicates whether the object exists.
456  */
457 int dmu_object_info(objset_t *os, uint64_t object, dmu_object_info_t *doi);
458 void dmu_object_info_from_dnode(struct dnode *dn, dmu_object_info_t *doi);
459 void dmu_object_info_from_db(dmu_buf_t *db, dmu_object_info_t *doi);
460 void dmu_object_size_from_db(dmu_buf_t *db, uint32_t *blksize,
461     u_longlong_t *nblk512);
462 
463 /*
464  * Get the maximum nonzero offset in the object (ie. this offset and all
465  * offsets following are zero).
466  *
467  * XXX Perhaps integrate this with dmu_object_info(), although that
468  * would then have to bring in the indirect blocks.
469  */
470 uint64_t dmu_object_max_nonzero_offset(objset_t *os, uint64_t object);
471 
472 typedef struct dmu_objset_stats {
473 	dmu_objset_type_t dds_type;
474 	uint8_t dds_is_snapshot;
475 	uint8_t dds_inconsistent;
476 	uint8_t dds_pad[2];
477 
478 	uint64_t dds_creation_time;
479 	uint64_t dds_creation_txg;
480 
481 	char dds_clone_of[MAXNAMELEN];
482 
483 	/* How much data is there in this objset? */
484 
485 	/*
486 	 * Space referenced, taking into account pending writes and
487 	 * frees.  Only relavent to filesystems and snapshots (not
488 	 * collections).
489 	 */
490 	uint64_t dds_space_refd;
491 
492 	/*
493 	 * Space "used", taking into account pending writes and frees, and
494 	 * children's reservations (in bytes).  This is the amount of
495 	 * space that will be freed if this and all dependent items are
496 	 * destroyed (eg. child datasets, objsets, and snapshots).  So
497 	 * for snapshots, this is the amount of space unique to this
498 	 * snapshot.
499 	 */
500 	uint64_t dds_space_used;
501 
502 	/*
503 	 * Compressed and uncompressed bytes consumed.  Does not take
504 	 * into account reservations.  Used for computing compression
505 	 * ratio.
506 	 */
507 	uint64_t dds_compressed_bytes;
508 	uint64_t dds_uncompressed_bytes;
509 
510 	/*
511 	 * The ds_fsid_guid is a 56-bit ID that can change to avoid
512 	 * collisions.  The ds_guid is a 64-bit ID that will never
513 	 * change, so there is a small probability that it will collide.
514 	 */
515 	uint64_t dds_fsid_guid;
516 
517 	uint64_t dds_objects_used;	/* number of objects used */
518 	uint64_t dds_objects_avail;	/* number of objects available */
519 
520 	uint64_t dds_num_clones; /* number of clones of this */
521 
522 	/* The dataset's administratively-set quota, in bytes. */
523 	uint64_t dds_quota;
524 
525 	/* The dataset's administratively-set reservation, in bytes */
526 	uint64_t dds_reserved;
527 
528 	/*
529 	 * The amount of additional space that this dataset can consume.
530 	 * Takes into account quotas & reservations.
531 	 * (Assuming that no other datasets consume it first.)
532 	 */
533 	uint64_t dds_available;
534 
535 	/*
536 	 * Used for debugging purposes
537 	 */
538 	uint64_t dds_last_txg;
539 } dmu_objset_stats_t;
540 
541 /*
542  * Get stats on a dataset.
543  */
544 void dmu_objset_stats(objset_t *os, dmu_objset_stats_t *dds);
545 
546 int dmu_objset_is_snapshot(objset_t *os);
547 
548 extern struct spa *dmu_objset_spa(objset_t *os);
549 extern struct zilog *dmu_objset_zil(objset_t *os);
550 extern struct dsl_pool *dmu_objset_pool(objset_t *os);
551 extern struct dsl_dataset *dmu_objset_ds(objset_t *os);
552 extern void dmu_objset_name(objset_t *os, char *buf);
553 extern dmu_objset_type_t dmu_objset_type(objset_t *os);
554 extern uint64_t dmu_objset_id(objset_t *os);
555 extern int dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
556     uint64_t *id, uint64_t *offp);
557 extern int dmu_dir_list_next(objset_t *os, int namelen, char *name,
558     uint64_t *idp, uint64_t *offp);
559 
560 /*
561  * Return the txg number for the given assigned transaction.
562  */
563 uint64_t dmu_tx_get_txg(dmu_tx_t *tx);
564 
565 /*
566  * Synchronous write.
567  * On success returns 0 and fills in the blk pointed at by bp.
568  * Note that while the data covered by this function will be on stable
569  * storage when the function returns this new data does not become a
570  * permanent part of the file until the associated transaction commits.
571  */
572 int dmu_sync(objset_t *os, uint64_t object, uint64_t offset, uint64_t *blkoff,
573     struct blkptr *bp, uint64_t txg);
574 
575 /*
576  * Find the next hole or data block in file starting at *off
577  * Return found offset in *off. Return ESRCH for end of file.
578  */
579 int dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole,
580     uint64_t *off);
581 
582 /*
583  * Initial setup and final teardown.
584  */
585 extern void dmu_init(void);
586 extern void dmu_fini(void);
587 
588 typedef void (*dmu_traverse_cb_t)(objset_t *os, void *arg, struct blkptr *bp,
589     uint64_t object, uint64_t offset, int len);
590 void dmu_traverse_objset(objset_t *os, uint64_t txg_start,
591     dmu_traverse_cb_t cb, void *arg);
592 
593 int dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, struct vnode *vp);
594 int dmu_recvbackup(char *tosnap, struct drr_begin *drrb, uint64_t *sizep,
595     struct vnode *vp, uint64_t voffset);
596 
597 /* CRC64 table */
598 #define	ZFS_CRC64_POLY	0xC96C5795D7870F42ULL	/* ECMA-182, reflected form */
599 extern uint64_t zfs_crc64_table[256];
600 
601 #ifdef	__cplusplus
602 }
603 #endif
604 
605 #endif	/* _SYS_DMU_H */
606