xref: /titanic_41/usr/src/uts/common/fs/zfs/sys/dmu.h (revision ad2de4358b2074634b0f2355c34b0986da0e95f9)
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 (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
23  * Copyright (c) 2011 by Delphix. All rights reserved.
24  */
25 /*
26  * Copyright 2011 Nexenta Systems, Inc. All rights reserved.
27  * Copyright (c) 2012, Joyent, Inc. All rights reserved.
28  */
29 
30 /* Portions Copyright 2010 Robert Milkowski */
31 
32 #ifndef	_SYS_DMU_H
33 #define	_SYS_DMU_H
34 
35 /*
36  * This file describes the interface that the DMU provides for its
37  * consumers.
38  *
39  * The DMU also interacts with the SPA.  That interface is described in
40  * dmu_spa.h.
41  */
42 
43 #include <sys/inttypes.h>
44 #include <sys/types.h>
45 #include <sys/param.h>
46 #include <sys/cred.h>
47 #include <sys/time.h>
48 
49 #ifdef	__cplusplus
50 extern "C" {
51 #endif
52 
53 struct uio;
54 struct xuio;
55 struct page;
56 struct vnode;
57 struct spa;
58 struct zilog;
59 struct zio;
60 struct blkptr;
61 struct zap_cursor;
62 struct dsl_dataset;
63 struct dsl_pool;
64 struct dnode;
65 struct drr_begin;
66 struct drr_end;
67 struct zbookmark;
68 struct spa;
69 struct nvlist;
70 struct arc_buf;
71 struct zio_prop;
72 struct sa_handle;
73 
74 typedef struct objset objset_t;
75 typedef struct dmu_tx dmu_tx_t;
76 typedef struct dsl_dir dsl_dir_t;
77 
78 typedef enum dmu_object_type {
79 	DMU_OT_NONE,
80 	/* general: */
81 	DMU_OT_OBJECT_DIRECTORY,	/* ZAP */
82 	DMU_OT_OBJECT_ARRAY,		/* UINT64 */
83 	DMU_OT_PACKED_NVLIST,		/* UINT8 (XDR by nvlist_pack/unpack) */
84 	DMU_OT_PACKED_NVLIST_SIZE,	/* UINT64 */
85 	DMU_OT_BPOBJ,			/* UINT64 */
86 	DMU_OT_BPOBJ_HDR,		/* UINT64 */
87 	/* spa: */
88 	DMU_OT_SPACE_MAP_HEADER,	/* UINT64 */
89 	DMU_OT_SPACE_MAP,		/* UINT64 */
90 	/* zil: */
91 	DMU_OT_INTENT_LOG,		/* UINT64 */
92 	/* dmu: */
93 	DMU_OT_DNODE,			/* DNODE */
94 	DMU_OT_OBJSET,			/* OBJSET */
95 	/* dsl: */
96 	DMU_OT_DSL_DIR,			/* UINT64 */
97 	DMU_OT_DSL_DIR_CHILD_MAP,	/* ZAP */
98 	DMU_OT_DSL_DS_SNAP_MAP,		/* ZAP */
99 	DMU_OT_DSL_PROPS,		/* ZAP */
100 	DMU_OT_DSL_DATASET,		/* UINT64 */
101 	/* zpl: */
102 	DMU_OT_ZNODE,			/* ZNODE */
103 	DMU_OT_OLDACL,			/* Old ACL */
104 	DMU_OT_PLAIN_FILE_CONTENTS,	/* UINT8 */
105 	DMU_OT_DIRECTORY_CONTENTS,	/* ZAP */
106 	DMU_OT_MASTER_NODE,		/* ZAP */
107 	DMU_OT_UNLINKED_SET,		/* ZAP */
108 	/* zvol: */
109 	DMU_OT_ZVOL,			/* UINT8 */
110 	DMU_OT_ZVOL_PROP,		/* ZAP */
111 	/* other; for testing only! */
112 	DMU_OT_PLAIN_OTHER,		/* UINT8 */
113 	DMU_OT_UINT64_OTHER,		/* UINT64 */
114 	DMU_OT_ZAP_OTHER,		/* ZAP */
115 	/* new object types: */
116 	DMU_OT_ERROR_LOG,		/* ZAP */
117 	DMU_OT_SPA_HISTORY,		/* UINT8 */
118 	DMU_OT_SPA_HISTORY_OFFSETS,	/* spa_his_phys_t */
119 	DMU_OT_POOL_PROPS,		/* ZAP */
120 	DMU_OT_DSL_PERMS,		/* ZAP */
121 	DMU_OT_ACL,			/* ACL */
122 	DMU_OT_SYSACL,			/* SYSACL */
123 	DMU_OT_FUID,			/* FUID table (Packed NVLIST UINT8) */
124 	DMU_OT_FUID_SIZE,		/* FUID table size UINT64 */
125 	DMU_OT_NEXT_CLONES,		/* ZAP */
126 	DMU_OT_SCAN_QUEUE,		/* ZAP */
127 	DMU_OT_USERGROUP_USED,		/* ZAP */
128 	DMU_OT_USERGROUP_QUOTA,		/* ZAP */
129 	DMU_OT_USERREFS,		/* ZAP */
130 	DMU_OT_DDT_ZAP,			/* ZAP */
131 	DMU_OT_DDT_STATS,		/* ZAP */
132 	DMU_OT_SA,			/* System attr */
133 	DMU_OT_SA_MASTER_NODE,		/* ZAP */
134 	DMU_OT_SA_ATTR_REGISTRATION,	/* ZAP */
135 	DMU_OT_SA_ATTR_LAYOUTS,		/* ZAP */
136 	DMU_OT_SCAN_XLATE,		/* ZAP */
137 	DMU_OT_DEDUP,			/* fake dedup BP from ddt_bp_create() */
138 	DMU_OT_DEADLIST,		/* ZAP */
139 	DMU_OT_DEADLIST_HDR,		/* UINT64 */
140 	DMU_OT_DSL_CLONES,		/* ZAP */
141 	DMU_OT_BPOBJ_SUBOBJ,		/* UINT64 */
142 	DMU_OT_NUMTYPES
143 } dmu_object_type_t;
144 
145 typedef enum dmu_objset_type {
146 	DMU_OST_NONE,
147 	DMU_OST_META,
148 	DMU_OST_ZFS,
149 	DMU_OST_ZVOL,
150 	DMU_OST_OTHER,			/* For testing only! */
151 	DMU_OST_ANY,			/* Be careful! */
152 	DMU_OST_NUMTYPES
153 } dmu_objset_type_t;
154 
155 void byteswap_uint64_array(void *buf, size_t size);
156 void byteswap_uint32_array(void *buf, size_t size);
157 void byteswap_uint16_array(void *buf, size_t size);
158 void byteswap_uint8_array(void *buf, size_t size);
159 void zap_byteswap(void *buf, size_t size);
160 void zfs_oldacl_byteswap(void *buf, size_t size);
161 void zfs_acl_byteswap(void *buf, size_t size);
162 void zfs_znode_byteswap(void *buf, size_t size);
163 
164 #define	DS_FIND_SNAPSHOTS	(1<<0)
165 #define	DS_FIND_CHILDREN	(1<<1)
166 
167 /*
168  * The maximum number of bytes that can be accessed as part of one
169  * operation, including metadata.
170  */
171 #define	DMU_MAX_ACCESS (10<<20) /* 10MB */
172 #define	DMU_MAX_DELETEBLKCNT (20480) /* ~5MB of indirect blocks */
173 
174 #define	DMU_USERUSED_OBJECT	(-1ULL)
175 #define	DMU_GROUPUSED_OBJECT	(-2ULL)
176 #define	DMU_DEADLIST_OBJECT	(-3ULL)
177 
178 /*
179  * artificial blkids for bonus buffer and spill blocks
180  */
181 #define	DMU_BONUS_BLKID		(-1ULL)
182 #define	DMU_SPILL_BLKID		(-2ULL)
183 /*
184  * Public routines to create, destroy, open, and close objsets.
185  */
186 int dmu_objset_hold(const char *name, void *tag, objset_t **osp);
187 int dmu_objset_own(const char *name, dmu_objset_type_t type,
188     boolean_t readonly, void *tag, objset_t **osp);
189 void dmu_objset_rele(objset_t *os, void *tag);
190 void dmu_objset_disown(objset_t *os, void *tag);
191 int dmu_objset_open_ds(struct dsl_dataset *ds, objset_t **osp);
192 
193 int dmu_objset_evict_dbufs(objset_t *os);
194 int dmu_objset_create(const char *name, dmu_objset_type_t type, uint64_t flags,
195     void (*func)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx), void *arg);
196 int dmu_objset_clone(const char *name, struct dsl_dataset *clone_origin,
197     uint64_t flags);
198 int dmu_objset_destroy(const char *name, boolean_t defer);
199 int dmu_snapshots_destroy_nvl(struct nvlist *snaps, boolean_t defer, char *);
200 int dmu_objset_snapshot(char *fsname, char *snapname, char *tag,
201     struct nvlist *props, boolean_t recursive, boolean_t temporary, int fd);
202 int dmu_objset_rename(const char *name, const char *newname,
203     boolean_t recursive);
204 int dmu_objset_find(char *name, int func(const char *, void *), void *arg,
205     int flags);
206 void dmu_objset_byteswap(void *buf, size_t size);
207 
208 typedef struct dmu_buf {
209 	uint64_t db_object;		/* object that this buffer is part of */
210 	uint64_t db_offset;		/* byte offset in this object */
211 	uint64_t db_size;		/* size of buffer in bytes */
212 	void *db_data;			/* data in buffer */
213 } dmu_buf_t;
214 
215 typedef void dmu_buf_evict_func_t(struct dmu_buf *db, void *user_ptr);
216 
217 /*
218  * The names of zap entries in the DIRECTORY_OBJECT of the MOS.
219  */
220 #define	DMU_POOL_DIRECTORY_OBJECT	1
221 #define	DMU_POOL_CONFIG			"config"
222 #define	DMU_POOL_ROOT_DATASET		"root_dataset"
223 #define	DMU_POOL_SYNC_BPOBJ		"sync_bplist"
224 #define	DMU_POOL_ERRLOG_SCRUB		"errlog_scrub"
225 #define	DMU_POOL_ERRLOG_LAST		"errlog_last"
226 #define	DMU_POOL_SPARES			"spares"
227 #define	DMU_POOL_DEFLATE		"deflate"
228 #define	DMU_POOL_HISTORY		"history"
229 #define	DMU_POOL_PROPS			"pool_props"
230 #define	DMU_POOL_L2CACHE		"l2cache"
231 #define	DMU_POOL_TMP_USERREFS		"tmp_userrefs"
232 #define	DMU_POOL_DDT			"DDT-%s-%s-%s"
233 #define	DMU_POOL_DDT_STATS		"DDT-statistics"
234 #define	DMU_POOL_CREATION_VERSION	"creation_version"
235 #define	DMU_POOL_SCAN			"scan"
236 #define	DMU_POOL_FREE_BPOBJ		"free_bpobj"
237 
238 /*
239  * Allocate an object from this objset.  The range of object numbers
240  * available is (0, DN_MAX_OBJECT).  Object 0 is the meta-dnode.
241  *
242  * The transaction must be assigned to a txg.  The newly allocated
243  * object will be "held" in the transaction (ie. you can modify the
244  * newly allocated object in this transaction).
245  *
246  * dmu_object_alloc() chooses an object and returns it in *objectp.
247  *
248  * dmu_object_claim() allocates a specific object number.  If that
249  * number is already allocated, it fails and returns EEXIST.
250  *
251  * Return 0 on success, or ENOSPC or EEXIST as specified above.
252  */
253 uint64_t dmu_object_alloc(objset_t *os, dmu_object_type_t ot,
254     int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
255 int dmu_object_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
256     int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
257 int dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
258     int blocksize, dmu_object_type_t bonustype, int bonuslen);
259 
260 /*
261  * Free an object from this objset.
262  *
263  * The object's data will be freed as well (ie. you don't need to call
264  * dmu_free(object, 0, -1, tx)).
265  *
266  * The object need not be held in the transaction.
267  *
268  * If there are any holds on this object's buffers (via dmu_buf_hold()),
269  * or tx holds on the object (via dmu_tx_hold_object()), you can not
270  * free it; it fails and returns EBUSY.
271  *
272  * If the object is not allocated, it fails and returns ENOENT.
273  *
274  * Return 0 on success, or EBUSY or ENOENT as specified above.
275  */
276 int dmu_object_free(objset_t *os, uint64_t object, dmu_tx_t *tx);
277 
278 /*
279  * Find the next allocated or free object.
280  *
281  * The objectp parameter is in-out.  It will be updated to be the next
282  * object which is allocated.  Ignore objects which have not been
283  * modified since txg.
284  *
285  * XXX Can only be called on a objset with no dirty data.
286  *
287  * Returns 0 on success, or ENOENT if there are no more objects.
288  */
289 int dmu_object_next(objset_t *os, uint64_t *objectp,
290     boolean_t hole, uint64_t txg);
291 
292 /*
293  * Set the data blocksize for an object.
294  *
295  * The object cannot have any blocks allcated beyond the first.  If
296  * the first block is allocated already, the new size must be greater
297  * than the current block size.  If these conditions are not met,
298  * ENOTSUP will be returned.
299  *
300  * Returns 0 on success, or EBUSY if there are any holds on the object
301  * contents, or ENOTSUP as described above.
302  */
303 int dmu_object_set_blocksize(objset_t *os, uint64_t object, uint64_t size,
304     int ibs, dmu_tx_t *tx);
305 
306 /*
307  * Set the checksum property on a dnode.  The new checksum algorithm will
308  * apply to all newly written blocks; existing blocks will not be affected.
309  */
310 void dmu_object_set_checksum(objset_t *os, uint64_t object, uint8_t checksum,
311     dmu_tx_t *tx);
312 
313 /*
314  * Set the compress property on a dnode.  The new compression algorithm will
315  * apply to all newly written blocks; existing blocks will not be affected.
316  */
317 void dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
318     dmu_tx_t *tx);
319 
320 /*
321  * Decide how to write a block: checksum, compression, number of copies, etc.
322  */
323 #define	WP_NOFILL	0x1
324 #define	WP_DMU_SYNC	0x2
325 #define	WP_SPILL	0x4
326 
327 void dmu_write_policy(objset_t *os, struct dnode *dn, int level, int wp,
328     struct zio_prop *zp);
329 /*
330  * The bonus data is accessed more or less like a regular buffer.
331  * You must dmu_bonus_hold() to get the buffer, which will give you a
332  * dmu_buf_t with db_offset==-1ULL, and db_size = the size of the bonus
333  * data.  As with any normal buffer, you must call dmu_buf_read() to
334  * read db_data, dmu_buf_will_dirty() before modifying it, and the
335  * object must be held in an assigned transaction before calling
336  * dmu_buf_will_dirty.  You may use dmu_buf_set_user() on the bonus
337  * buffer as well.  You must release your hold with dmu_buf_rele().
338  */
339 int dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **);
340 int dmu_bonus_max(void);
341 int dmu_set_bonus(dmu_buf_t *, int, dmu_tx_t *);
342 int dmu_set_bonustype(dmu_buf_t *, dmu_object_type_t, dmu_tx_t *);
343 dmu_object_type_t dmu_get_bonustype(dmu_buf_t *);
344 int dmu_rm_spill(objset_t *, uint64_t, dmu_tx_t *);
345 
346 /*
347  * Special spill buffer support used by "SA" framework
348  */
349 
350 int dmu_spill_hold_by_bonus(dmu_buf_t *bonus, void *tag, dmu_buf_t **dbp);
351 int dmu_spill_hold_by_dnode(struct dnode *dn, uint32_t flags,
352     void *tag, dmu_buf_t **dbp);
353 int dmu_spill_hold_existing(dmu_buf_t *bonus, void *tag, dmu_buf_t **dbp);
354 
355 /*
356  * Obtain the DMU buffer from the specified object which contains the
357  * specified offset.  dmu_buf_hold() puts a "hold" on the buffer, so
358  * that it will remain in memory.  You must release the hold with
359  * dmu_buf_rele().  You musn't access the dmu_buf_t after releasing your
360  * hold.  You must have a hold on any dmu_buf_t* you pass to the DMU.
361  *
362  * You must call dmu_buf_read, dmu_buf_will_dirty, or dmu_buf_will_fill
363  * on the returned buffer before reading or writing the buffer's
364  * db_data.  The comments for those routines describe what particular
365  * operations are valid after calling them.
366  *
367  * The object number must be a valid, allocated object number.
368  */
369 int dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
370     void *tag, dmu_buf_t **, int flags);
371 void dmu_buf_add_ref(dmu_buf_t *db, void* tag);
372 void dmu_buf_rele(dmu_buf_t *db, void *tag);
373 uint64_t dmu_buf_refcount(dmu_buf_t *db);
374 
375 /*
376  * dmu_buf_hold_array holds the DMU buffers which contain all bytes in a
377  * range of an object.  A pointer to an array of dmu_buf_t*'s is
378  * returned (in *dbpp).
379  *
380  * dmu_buf_rele_array releases the hold on an array of dmu_buf_t*'s, and
381  * frees the array.  The hold on the array of buffers MUST be released
382  * with dmu_buf_rele_array.  You can NOT release the hold on each buffer
383  * individually with dmu_buf_rele.
384  */
385 int dmu_buf_hold_array_by_bonus(dmu_buf_t *db, uint64_t offset,
386     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp);
387 void dmu_buf_rele_array(dmu_buf_t **, int numbufs, void *tag);
388 
389 /*
390  * Returns NULL on success, or the existing user ptr if it's already
391  * been set.
392  *
393  * user_ptr is for use by the user and can be obtained via dmu_buf_get_user().
394  *
395  * user_data_ptr_ptr should be NULL, or a pointer to a pointer which
396  * will be set to db->db_data when you are allowed to access it.  Note
397  * that db->db_data (the pointer) can change when you do dmu_buf_read(),
398  * dmu_buf_tryupgrade(), dmu_buf_will_dirty(), or dmu_buf_will_fill().
399  * *user_data_ptr_ptr will be set to the new value when it changes.
400  *
401  * If non-NULL, pageout func will be called when this buffer is being
402  * excised from the cache, so that you can clean up the data structure
403  * pointed to by user_ptr.
404  *
405  * dmu_evict_user() will call the pageout func for all buffers in a
406  * objset with a given pageout func.
407  */
408 void *dmu_buf_set_user(dmu_buf_t *db, void *user_ptr, void *user_data_ptr_ptr,
409     dmu_buf_evict_func_t *pageout_func);
410 /*
411  * set_user_ie is the same as set_user, but request immediate eviction
412  * when hold count goes to zero.
413  */
414 void *dmu_buf_set_user_ie(dmu_buf_t *db, void *user_ptr,
415     void *user_data_ptr_ptr, dmu_buf_evict_func_t *pageout_func);
416 void *dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr,
417     void *user_ptr, void *user_data_ptr_ptr,
418     dmu_buf_evict_func_t *pageout_func);
419 void dmu_evict_user(objset_t *os, dmu_buf_evict_func_t *func);
420 
421 /*
422  * Returns the user_ptr set with dmu_buf_set_user(), or NULL if not set.
423  */
424 void *dmu_buf_get_user(dmu_buf_t *db);
425 
426 /*
427  * Indicate that you are going to modify the buffer's data (db_data).
428  *
429  * The transaction (tx) must be assigned to a txg (ie. you've called
430  * dmu_tx_assign()).  The buffer's object must be held in the tx
431  * (ie. you've called dmu_tx_hold_object(tx, db->db_object)).
432  */
433 void dmu_buf_will_dirty(dmu_buf_t *db, dmu_tx_t *tx);
434 
435 /*
436  * Tells if the given dbuf is freeable.
437  */
438 boolean_t dmu_buf_freeable(dmu_buf_t *);
439 
440 /*
441  * You must create a transaction, then hold the objects which you will
442  * (or might) modify as part of this transaction.  Then you must assign
443  * the transaction to a transaction group.  Once the transaction has
444  * been assigned, you can modify buffers which belong to held objects as
445  * part of this transaction.  You can't modify buffers before the
446  * transaction has been assigned; you can't modify buffers which don't
447  * belong to objects which this transaction holds; you can't hold
448  * objects once the transaction has been assigned.  You may hold an
449  * object which you are going to free (with dmu_object_free()), but you
450  * don't have to.
451  *
452  * You can abort the transaction before it has been assigned.
453  *
454  * Note that you may hold buffers (with dmu_buf_hold) at any time,
455  * regardless of transaction state.
456  */
457 
458 #define	DMU_NEW_OBJECT	(-1ULL)
459 #define	DMU_OBJECT_END	(-1ULL)
460 
461 dmu_tx_t *dmu_tx_create(objset_t *os);
462 void dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len);
463 void dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off,
464     uint64_t len);
465 void dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, const char *name);
466 void dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object);
467 void dmu_tx_hold_spill(dmu_tx_t *tx, uint64_t object);
468 void dmu_tx_hold_sa(dmu_tx_t *tx, struct sa_handle *hdl, boolean_t may_grow);
469 void dmu_tx_hold_sa_create(dmu_tx_t *tx, int total_size);
470 void dmu_tx_abort(dmu_tx_t *tx);
471 int dmu_tx_assign(dmu_tx_t *tx, uint64_t txg_how);
472 void dmu_tx_wait(dmu_tx_t *tx);
473 void dmu_tx_commit(dmu_tx_t *tx);
474 
475 /*
476  * To register a commit callback, dmu_tx_callback_register() must be called.
477  *
478  * dcb_data is a pointer to caller private data that is passed on as a
479  * callback parameter. The caller is responsible for properly allocating and
480  * freeing it.
481  *
482  * When registering a callback, the transaction must be already created, but
483  * it cannot be committed or aborted. It can be assigned to a txg or not.
484  *
485  * The callback will be called after the transaction has been safely written
486  * to stable storage and will also be called if the dmu_tx is aborted.
487  * If there is any error which prevents the transaction from being committed to
488  * disk, the callback will be called with a value of error != 0.
489  */
490 typedef void dmu_tx_callback_func_t(void *dcb_data, int error);
491 
492 void dmu_tx_callback_register(dmu_tx_t *tx, dmu_tx_callback_func_t *dcb_func,
493     void *dcb_data);
494 
495 /*
496  * Free up the data blocks for a defined range of a file.  If size is
497  * zero, the range from offset to end-of-file is freed.
498  */
499 int dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
500 	uint64_t size, dmu_tx_t *tx);
501 int dmu_free_long_range(objset_t *os, uint64_t object, uint64_t offset,
502 	uint64_t size);
503 int dmu_free_object(objset_t *os, uint64_t object);
504 
505 /*
506  * Convenience functions.
507  *
508  * Canfail routines will return 0 on success, or an errno if there is a
509  * nonrecoverable I/O error.
510  */
511 #define	DMU_READ_PREFETCH	0 /* prefetch */
512 #define	DMU_READ_NO_PREFETCH	1 /* don't prefetch */
513 int dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
514 	void *buf, uint32_t flags);
515 void dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
516 	const void *buf, dmu_tx_t *tx);
517 void dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
518 	dmu_tx_t *tx);
519 int dmu_read_uio(objset_t *os, uint64_t object, struct uio *uio, uint64_t size);
520 int dmu_write_uio(objset_t *os, uint64_t object, struct uio *uio, uint64_t size,
521     dmu_tx_t *tx);
522 int dmu_write_uio_dbuf(dmu_buf_t *zdb, struct uio *uio, uint64_t size,
523     dmu_tx_t *tx);
524 int dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset,
525     uint64_t size, struct page *pp, dmu_tx_t *tx);
526 struct arc_buf *dmu_request_arcbuf(dmu_buf_t *handle, int size);
527 void dmu_return_arcbuf(struct arc_buf *buf);
528 void dmu_assign_arcbuf(dmu_buf_t *handle, uint64_t offset, struct arc_buf *buf,
529     dmu_tx_t *tx);
530 int dmu_xuio_init(struct xuio *uio, int niov);
531 void dmu_xuio_fini(struct xuio *uio);
532 int dmu_xuio_add(struct xuio *uio, struct arc_buf *abuf, offset_t off,
533     size_t n);
534 int dmu_xuio_cnt(struct xuio *uio);
535 struct arc_buf *dmu_xuio_arcbuf(struct xuio *uio, int i);
536 void dmu_xuio_clear(struct xuio *uio, int i);
537 void xuio_stat_wbuf_copied();
538 void xuio_stat_wbuf_nocopy();
539 
540 extern int zfs_prefetch_disable;
541 
542 /*
543  * Asynchronously try to read in the data.
544  */
545 void dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset,
546     uint64_t len);
547 
548 typedef struct dmu_object_info {
549 	/* All sizes are in bytes unless otherwise indicated. */
550 	uint32_t doi_data_block_size;
551 	uint32_t doi_metadata_block_size;
552 	dmu_object_type_t doi_type;
553 	dmu_object_type_t doi_bonus_type;
554 	uint64_t doi_bonus_size;
555 	uint8_t doi_indirection;		/* 2 = dnode->indirect->data */
556 	uint8_t doi_checksum;
557 	uint8_t doi_compress;
558 	uint8_t doi_pad[5];
559 	uint64_t doi_physical_blocks_512;	/* data + metadata, 512b blks */
560 	uint64_t doi_max_offset;
561 	uint64_t doi_fill_count;		/* number of non-empty blocks */
562 } dmu_object_info_t;
563 
564 typedef void arc_byteswap_func_t(void *buf, size_t size);
565 
566 typedef struct dmu_object_type_info {
567 	arc_byteswap_func_t	*ot_byteswap;
568 	boolean_t		ot_metadata;
569 	char			*ot_name;
570 } dmu_object_type_info_t;
571 
572 extern const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES];
573 
574 /*
575  * Get information on a DMU object.
576  *
577  * Return 0 on success or ENOENT if object is not allocated.
578  *
579  * If doi is NULL, just indicates whether the object exists.
580  */
581 int dmu_object_info(objset_t *os, uint64_t object, dmu_object_info_t *doi);
582 void dmu_object_info_from_dnode(struct dnode *dn, dmu_object_info_t *doi);
583 void dmu_object_info_from_db(dmu_buf_t *db, dmu_object_info_t *doi);
584 void dmu_object_size_from_db(dmu_buf_t *db, uint32_t *blksize,
585     u_longlong_t *nblk512);
586 
587 typedef struct dmu_objset_stats {
588 	uint64_t dds_num_clones; /* number of clones of this */
589 	uint64_t dds_creation_txg;
590 	uint64_t dds_guid;
591 	dmu_objset_type_t dds_type;
592 	uint8_t dds_is_snapshot;
593 	uint8_t dds_inconsistent;
594 	char dds_origin[MAXNAMELEN];
595 } dmu_objset_stats_t;
596 
597 /*
598  * Get stats on a dataset.
599  */
600 void dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat);
601 
602 /*
603  * Add entries to the nvlist for all the objset's properties.  See
604  * zfs_prop_table[] and zfs(1m) for details on the properties.
605  */
606 void dmu_objset_stats(objset_t *os, struct nvlist *nv);
607 
608 /*
609  * Get the space usage statistics for statvfs().
610  *
611  * refdbytes is the amount of space "referenced" by this objset.
612  * availbytes is the amount of space available to this objset, taking
613  * into account quotas & reservations, assuming that no other objsets
614  * use the space first.  These values correspond to the 'referenced' and
615  * 'available' properties, described in the zfs(1m) manpage.
616  *
617  * usedobjs and availobjs are the number of objects currently allocated,
618  * and available.
619  */
620 void dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
621     uint64_t *usedobjsp, uint64_t *availobjsp);
622 
623 /*
624  * The fsid_guid is a 56-bit ID that can change to avoid collisions.
625  * (Contrast with the ds_guid which is a 64-bit ID that will never
626  * change, so there is a small probability that it will collide.)
627  */
628 uint64_t dmu_objset_fsid_guid(objset_t *os);
629 
630 /*
631  * Get the [cm]time for an objset's snapshot dir
632  */
633 timestruc_t dmu_objset_snap_cmtime(objset_t *os);
634 
635 int dmu_objset_is_snapshot(objset_t *os);
636 
637 extern struct spa *dmu_objset_spa(objset_t *os);
638 extern struct zilog *dmu_objset_zil(objset_t *os);
639 extern struct dsl_pool *dmu_objset_pool(objset_t *os);
640 extern struct dsl_dataset *dmu_objset_ds(objset_t *os);
641 extern void dmu_objset_name(objset_t *os, char *buf);
642 extern dmu_objset_type_t dmu_objset_type(objset_t *os);
643 extern uint64_t dmu_objset_id(objset_t *os);
644 extern uint64_t dmu_objset_syncprop(objset_t *os);
645 extern uint64_t dmu_objset_logbias(objset_t *os);
646 extern int dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
647     uint64_t *id, uint64_t *offp, boolean_t *case_conflict);
648 extern int dmu_snapshot_realname(objset_t *os, char *name, char *real,
649     int maxlen, boolean_t *conflict);
650 extern int dmu_dir_list_next(objset_t *os, int namelen, char *name,
651     uint64_t *idp, uint64_t *offp);
652 
653 typedef int objset_used_cb_t(dmu_object_type_t bonustype,
654     void *bonus, uint64_t *userp, uint64_t *groupp);
655 extern void dmu_objset_register_type(dmu_objset_type_t ost,
656     objset_used_cb_t *cb);
657 extern void dmu_objset_set_user(objset_t *os, void *user_ptr);
658 extern void *dmu_objset_get_user(objset_t *os);
659 
660 /*
661  * Return the txg number for the given assigned transaction.
662  */
663 uint64_t dmu_tx_get_txg(dmu_tx_t *tx);
664 
665 /*
666  * Synchronous write.
667  * If a parent zio is provided this function initiates a write on the
668  * provided buffer as a child of the parent zio.
669  * In the absence of a parent zio, the write is completed synchronously.
670  * At write completion, blk is filled with the bp of the written block.
671  * Note that while the data covered by this function will be on stable
672  * storage when the write completes this new data does not become a
673  * permanent part of the file until the associated transaction commits.
674  */
675 
676 /*
677  * {zfs,zvol,ztest}_get_done() args
678  */
679 typedef struct zgd {
680 	struct zilog	*zgd_zilog;
681 	struct blkptr	*zgd_bp;
682 	dmu_buf_t	*zgd_db;
683 	struct rl	*zgd_rl;
684 	void		*zgd_private;
685 } zgd_t;
686 
687 typedef void dmu_sync_cb_t(zgd_t *arg, int error);
688 int dmu_sync(struct zio *zio, uint64_t txg, dmu_sync_cb_t *done, zgd_t *zgd);
689 
690 /*
691  * Find the next hole or data block in file starting at *off
692  * Return found offset in *off. Return ESRCH for end of file.
693  */
694 int dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole,
695     uint64_t *off);
696 
697 /*
698  * Initial setup and final teardown.
699  */
700 extern void dmu_init(void);
701 extern void dmu_fini(void);
702 
703 typedef void (*dmu_traverse_cb_t)(objset_t *os, void *arg, struct blkptr *bp,
704     uint64_t object, uint64_t offset, int len);
705 void dmu_traverse_objset(objset_t *os, uint64_t txg_start,
706     dmu_traverse_cb_t cb, void *arg);
707 
708 int dmu_send(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
709     int outfd, struct vnode *vp, offset_t *off);
710 int dmu_send_estimate(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorign,
711     uint64_t *sizep);
712 
713 typedef struct dmu_recv_cookie {
714 	/*
715 	 * This structure is opaque!
716 	 *
717 	 * If logical and real are different, we are recving the stream
718 	 * into the "real" temporary clone, and then switching it with
719 	 * the "logical" target.
720 	 */
721 	struct dsl_dataset *drc_logical_ds;
722 	struct dsl_dataset *drc_real_ds;
723 	struct drr_begin *drc_drrb;
724 	char *drc_tosnap;
725 	char *drc_top_ds;
726 	boolean_t drc_newfs;
727 	boolean_t drc_force;
728 	struct avl_tree *drc_guid_to_ds_map;
729 } dmu_recv_cookie_t;
730 
731 int dmu_recv_begin(char *tofs, char *tosnap, char *topds, struct drr_begin *,
732     boolean_t force, objset_t *origin, dmu_recv_cookie_t *);
733 int dmu_recv_stream(dmu_recv_cookie_t *drc, struct vnode *vp, offset_t *voffp,
734     int cleanup_fd, uint64_t *action_handlep);
735 int dmu_recv_end(dmu_recv_cookie_t *drc);
736 
737 int dmu_diff(objset_t *tosnap, objset_t *fromsnap, struct vnode *vp,
738     offset_t *off);
739 
740 /* CRC64 table */
741 #define	ZFS_CRC64_POLY	0xC96C5795D7870F42ULL	/* ECMA-182, reflected form */
742 extern uint64_t zfs_crc64_table[256];
743 
744 #ifdef	__cplusplus
745 }
746 #endif
747 
748 #endif	/* _SYS_DMU_H */
749