xref: /trueos/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/dmu.h (revision b878ae0412195c252dc69da54b764deab388e210)
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  */
30 
31 /* Portions Copyright 2010 Robert Milkowski */
32 
33 #ifndef	_SYS_DMU_H
34 #define	_SYS_DMU_H
35 
36 /*
37  * This file describes the interface that the DMU provides for its
38  * consumers.
39  *
40  * The DMU also interacts with the SPA.  That interface is described in
41  * dmu_spa.h.
42  */
43 
44 #include <sys/types.h>
45 #include <sys/param.h>
46 #include <sys/cred.h>
47 #include <sys/time.h>
48 #include <sys/fs/zfs.h>
49 
50 #ifdef	__cplusplus
51 extern "C" {
52 #endif
53 
54 struct uio;
55 struct xuio;
56 struct page;
57 struct vnode;
58 struct spa;
59 struct zilog;
60 struct zio;
61 struct blkptr;
62 struct zap_cursor;
63 struct dsl_dataset;
64 struct dsl_pool;
65 struct dnode;
66 struct drr_begin;
67 struct drr_end;
68 struct zbookmark_phys;
69 struct spa;
70 struct nvlist;
71 struct arc_buf;
72 struct zio_prop;
73 struct sa_handle;
74 struct file;
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 
248 /*
249  * The maximum number of bytes that can be accessed as part of one
250  * operation, including metadata.
251  */
252 #define	DMU_MAX_ACCESS (32 * 1024 * 1024) /* 32MB */
253 #define	DMU_MAX_DELETEBLKCNT (20480) /* ~5MB of indirect blocks */
254 
255 #define	DMU_USERUSED_OBJECT	(-1ULL)
256 #define	DMU_GROUPUSED_OBJECT	(-2ULL)
257 
258 /*
259  * artificial blkids for bonus buffer and spill blocks
260  */
261 #define	DMU_BONUS_BLKID		(-1ULL)
262 #define	DMU_SPILL_BLKID		(-2ULL)
263 /*
264  * Public routines to create, destroy, open, and close objsets.
265  */
266 int dmu_objset_hold(const char *name, void *tag, objset_t **osp);
267 int dmu_objset_own(const char *name, dmu_objset_type_t type,
268     boolean_t readonly, void *tag, objset_t **osp);
269 void dmu_objset_rele(objset_t *os, void *tag);
270 void dmu_objset_disown(objset_t *os, void *tag);
271 int dmu_objset_open_ds(struct dsl_dataset *ds, objset_t **osp);
272 
273 void dmu_objset_evict_dbufs(objset_t *os);
274 int dmu_objset_create(const char *name, dmu_objset_type_t type, uint64_t flags,
275     void (*func)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx), void *arg);
276 int dmu_get_recursive_snaps_nvl(char *fsname, const char *snapname,
277     struct nvlist *snaps);
278 int dmu_objset_clone(const char *name, const char *origin);
279 int dsl_destroy_snapshots_nvl(struct nvlist *snaps, boolean_t defer,
280     struct nvlist *errlist);
281 int dmu_objset_snapshot_one(const char *fsname, const char *snapname);
282 int dmu_objset_snapshot_tmp(const char *, const char *, int);
283 int dmu_objset_find(char *name, int func(const char *, void *), void *arg,
284     int flags);
285 void dmu_objset_byteswap(void *buf, size_t size);
286 int dsl_dataset_rename_snapshot(const char *fsname,
287     const char *oldsnapname, const char *newsnapname, boolean_t recursive);
288 
289 typedef struct dmu_buf {
290 	uint64_t db_object;		/* object that this buffer is part of */
291 	uint64_t db_offset;		/* byte offset in this object */
292 	uint64_t db_size;		/* size of buffer in bytes */
293 	void *db_data;			/* data in buffer */
294 } dmu_buf_t;
295 
296 typedef void dmu_buf_evict_func_t(struct dmu_buf *db, void *user_ptr);
297 
298 /*
299  * The names of zap entries in the DIRECTORY_OBJECT of the MOS.
300  */
301 #define	DMU_POOL_DIRECTORY_OBJECT	1
302 #define	DMU_POOL_CONFIG			"config"
303 #define	DMU_POOL_FEATURES_FOR_WRITE	"features_for_write"
304 #define	DMU_POOL_FEATURES_FOR_READ	"features_for_read"
305 #define	DMU_POOL_FEATURE_DESCRIPTIONS	"feature_descriptions"
306 #define	DMU_POOL_FEATURE_ENABLED_TXG	"feature_enabled_txg"
307 #define	DMU_POOL_ROOT_DATASET		"root_dataset"
308 #define	DMU_POOL_SYNC_BPOBJ		"sync_bplist"
309 #define	DMU_POOL_ERRLOG_SCRUB		"errlog_scrub"
310 #define	DMU_POOL_ERRLOG_LAST		"errlog_last"
311 #define	DMU_POOL_SPARES			"spares"
312 #define	DMU_POOL_DEFLATE		"deflate"
313 #define	DMU_POOL_HISTORY		"history"
314 #define	DMU_POOL_PROPS			"pool_props"
315 #define	DMU_POOL_L2CACHE		"l2cache"
316 #define	DMU_POOL_TMP_USERREFS		"tmp_userrefs"
317 #define	DMU_POOL_DDT			"DDT-%s-%s-%s"
318 #define	DMU_POOL_DDT_STATS		"DDT-statistics"
319 #define	DMU_POOL_CREATION_VERSION	"creation_version"
320 #define	DMU_POOL_SCAN			"scan"
321 #define	DMU_POOL_FREE_BPOBJ		"free_bpobj"
322 #define	DMU_POOL_BPTREE_OBJ		"bptree_obj"
323 #define	DMU_POOL_EMPTY_BPOBJ		"empty_bpobj"
324 
325 /*
326  * Allocate an object from this objset.  The range of object numbers
327  * available is (0, DN_MAX_OBJECT).  Object 0 is the meta-dnode.
328  *
329  * The transaction must be assigned to a txg.  The newly allocated
330  * object will be "held" in the transaction (ie. you can modify the
331  * newly allocated object in this transaction).
332  *
333  * dmu_object_alloc() chooses an object and returns it in *objectp.
334  *
335  * dmu_object_claim() allocates a specific object number.  If that
336  * number is already allocated, it fails and returns EEXIST.
337  *
338  * Return 0 on success, or ENOSPC or EEXIST as specified above.
339  */
340 uint64_t dmu_object_alloc(objset_t *os, dmu_object_type_t ot,
341     int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
342 int dmu_object_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
343     int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
344 int dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
345     int blocksize, dmu_object_type_t bonustype, int bonuslen, dmu_tx_t *txp);
346 
347 /*
348  * Free an object from this objset.
349  *
350  * The object's data will be freed as well (ie. you don't need to call
351  * dmu_free(object, 0, -1, tx)).
352  *
353  * The object need not be held in the transaction.
354  *
355  * If there are any holds on this object's buffers (via dmu_buf_hold()),
356  * or tx holds on the object (via dmu_tx_hold_object()), you can not
357  * free it; it fails and returns EBUSY.
358  *
359  * If the object is not allocated, it fails and returns ENOENT.
360  *
361  * Return 0 on success, or EBUSY or ENOENT as specified above.
362  */
363 int dmu_object_free(objset_t *os, uint64_t object, dmu_tx_t *tx);
364 
365 /*
366  * Find the next allocated or free object.
367  *
368  * The objectp parameter is in-out.  It will be updated to be the next
369  * object which is allocated.  Ignore objects which have not been
370  * modified since txg.
371  *
372  * XXX Can only be called on a objset with no dirty data.
373  *
374  * Returns 0 on success, or ENOENT if there are no more objects.
375  */
376 int dmu_object_next(objset_t *os, uint64_t *objectp,
377     boolean_t hole, uint64_t txg);
378 
379 /*
380  * Set the data blocksize for an object.
381  *
382  * The object cannot have any blocks allcated beyond the first.  If
383  * the first block is allocated already, the new size must be greater
384  * than the current block size.  If these conditions are not met,
385  * ENOTSUP will be returned.
386  *
387  * Returns 0 on success, or EBUSY if there are any holds on the object
388  * contents, or ENOTSUP as described above.
389  */
390 int dmu_object_set_blocksize(objset_t *os, uint64_t object, uint64_t size,
391     int ibs, dmu_tx_t *tx);
392 
393 /*
394  * Set the checksum property on a dnode.  The new checksum algorithm will
395  * apply to all newly written blocks; existing blocks will not be affected.
396  */
397 void dmu_object_set_checksum(objset_t *os, uint64_t object, uint8_t checksum,
398     dmu_tx_t *tx);
399 
400 /*
401  * Set the compress property on a dnode.  The new compression algorithm will
402  * apply to all newly written blocks; existing blocks will not be affected.
403  */
404 void dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
405     dmu_tx_t *tx);
406 
407 void
408 dmu_write_embedded(objset_t *os, uint64_t object, uint64_t offset,
409     void *data, uint8_t etype, uint8_t comp, int uncompressed_size,
410     int compressed_size, int byteorder, dmu_tx_t *tx);
411 
412 /*
413  * Decide how to write a block: checksum, compression, number of copies, etc.
414  */
415 #define	WP_NOFILL	0x1
416 #define	WP_DMU_SYNC	0x2
417 #define	WP_SPILL	0x4
418 
419 void dmu_write_policy(objset_t *os, struct dnode *dn, int level, int wp,
420     struct zio_prop *zp);
421 /*
422  * The bonus data is accessed more or less like a regular buffer.
423  * You must dmu_bonus_hold() to get the buffer, which will give you a
424  * dmu_buf_t with db_offset==-1ULL, and db_size = the size of the bonus
425  * data.  As with any normal buffer, you must call dmu_buf_read() to
426  * read db_data, dmu_buf_will_dirty() before modifying it, and the
427  * object must be held in an assigned transaction before calling
428  * dmu_buf_will_dirty.  You may use dmu_buf_set_user() on the bonus
429  * buffer as well.  You must release your hold with dmu_buf_rele().
430  *
431  * Returns ENOENT, EIO, or 0.
432  */
433 int dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **);
434 int dmu_bonus_max(void);
435 int dmu_set_bonus(dmu_buf_t *, int, dmu_tx_t *);
436 int dmu_set_bonustype(dmu_buf_t *, dmu_object_type_t, dmu_tx_t *);
437 dmu_object_type_t dmu_get_bonustype(dmu_buf_t *);
438 int dmu_rm_spill(objset_t *, uint64_t, dmu_tx_t *);
439 
440 /*
441  * Special spill buffer support used by "SA" framework
442  */
443 
444 int dmu_spill_hold_by_bonus(dmu_buf_t *bonus, void *tag, dmu_buf_t **dbp);
445 int dmu_spill_hold_by_dnode(struct dnode *dn, uint32_t flags,
446     void *tag, dmu_buf_t **dbp);
447 int dmu_spill_hold_existing(dmu_buf_t *bonus, void *tag, dmu_buf_t **dbp);
448 
449 /*
450  * Obtain the DMU buffer from the specified object which contains the
451  * specified offset.  dmu_buf_hold() puts a "hold" on the buffer, so
452  * that it will remain in memory.  You must release the hold with
453  * dmu_buf_rele().  You musn't access the dmu_buf_t after releasing your
454  * hold.  You must have a hold on any dmu_buf_t* you pass to the DMU.
455  *
456  * You must call dmu_buf_read, dmu_buf_will_dirty, or dmu_buf_will_fill
457  * on the returned buffer before reading or writing the buffer's
458  * db_data.  The comments for those routines describe what particular
459  * operations are valid after calling them.
460  *
461  * The object number must be a valid, allocated object number.
462  */
463 int dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
464     void *tag, dmu_buf_t **, int flags);
465 void dmu_buf_add_ref(dmu_buf_t *db, void* tag);
466 void dmu_buf_rele(dmu_buf_t *db, void *tag);
467 uint64_t dmu_buf_refcount(dmu_buf_t *db);
468 
469 /*
470  * dmu_buf_hold_array holds the DMU buffers which contain all bytes in a
471  * range of an object.  A pointer to an array of dmu_buf_t*'s is
472  * returned (in *dbpp).
473  *
474  * dmu_buf_rele_array releases the hold on an array of dmu_buf_t*'s, and
475  * frees the array.  The hold on the array of buffers MUST be released
476  * with dmu_buf_rele_array.  You can NOT release the hold on each buffer
477  * individually with dmu_buf_rele.
478  */
479 int dmu_buf_hold_array_by_bonus(dmu_buf_t *db, uint64_t offset,
480     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp);
481 void dmu_buf_rele_array(dmu_buf_t **, int numbufs, void *tag);
482 
483 /*
484  * Returns NULL on success, or the existing user ptr if it's already
485  * been set.
486  *
487  * user_ptr is for use by the user and can be obtained via dmu_buf_get_user().
488  *
489  * If non-NULL, pageout func will be called when this buffer is being
490  * excised from the cache, so that you can clean up the data structure
491  * pointed to by user_ptr.
492  *
493  * dmu_evict_user() will call the pageout func for all buffers in a
494  * objset with a given pageout func.
495  */
496 void *dmu_buf_set_user(dmu_buf_t *db, void *user_ptr,
497     dmu_buf_evict_func_t *pageout_func);
498 /*
499  * set_user_ie is the same as set_user, but request immediate eviction
500  * when hold count goes to zero.
501  */
502 void *dmu_buf_set_user_ie(dmu_buf_t *db, void *user_ptr,
503     dmu_buf_evict_func_t *pageout_func);
504 void *dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr,
505     void *user_ptr, dmu_buf_evict_func_t *pageout_func);
506 void dmu_evict_user(objset_t *os, dmu_buf_evict_func_t *func);
507 
508 /*
509  * Returns the user_ptr set with dmu_buf_set_user(), or NULL if not set.
510  */
511 void *dmu_buf_get_user(dmu_buf_t *db);
512 
513 /*
514  * Returns the blkptr associated with this dbuf, or NULL if not set.
515  */
516 struct blkptr *dmu_buf_get_blkptr(dmu_buf_t *db);
517 
518 /*
519  * Indicate that you are going to modify the buffer's data (db_data).
520  *
521  * The transaction (tx) must be assigned to a txg (ie. you've called
522  * dmu_tx_assign()).  The buffer's object must be held in the tx
523  * (ie. you've called dmu_tx_hold_object(tx, db->db_object)).
524  */
525 void dmu_buf_will_dirty(dmu_buf_t *db, dmu_tx_t *tx);
526 
527 /*
528  * Tells if the given dbuf is freeable.
529  */
530 boolean_t dmu_buf_freeable(dmu_buf_t *);
531 
532 /*
533  * You must create a transaction, then hold the objects which you will
534  * (or might) modify as part of this transaction.  Then you must assign
535  * the transaction to a transaction group.  Once the transaction has
536  * been assigned, you can modify buffers which belong to held objects as
537  * part of this transaction.  You can't modify buffers before the
538  * transaction has been assigned; you can't modify buffers which don't
539  * belong to objects which this transaction holds; you can't hold
540  * objects once the transaction has been assigned.  You may hold an
541  * object which you are going to free (with dmu_object_free()), but you
542  * don't have to.
543  *
544  * You can abort the transaction before it has been assigned.
545  *
546  * Note that you may hold buffers (with dmu_buf_hold) at any time,
547  * regardless of transaction state.
548  */
549 
550 #define	DMU_NEW_OBJECT	(-1ULL)
551 #define	DMU_OBJECT_END	(-1ULL)
552 
553 dmu_tx_t *dmu_tx_create(objset_t *os);
554 void dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len);
555 void dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off,
556     uint64_t len);
557 void dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, const char *name);
558 void dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object);
559 void dmu_tx_hold_spill(dmu_tx_t *tx, uint64_t object);
560 void dmu_tx_hold_sa(dmu_tx_t *tx, struct sa_handle *hdl, boolean_t may_grow);
561 void dmu_tx_hold_sa_create(dmu_tx_t *tx, int total_size);
562 void dmu_tx_abort(dmu_tx_t *tx);
563 int dmu_tx_assign(dmu_tx_t *tx, enum txg_how txg_how);
564 void dmu_tx_wait(dmu_tx_t *tx);
565 void dmu_tx_commit(dmu_tx_t *tx);
566 void dmu_tx_mark_netfree(dmu_tx_t *tx);
567 
568 /*
569  * To register a commit callback, dmu_tx_callback_register() must be called.
570  *
571  * dcb_data is a pointer to caller private data that is passed on as a
572  * callback parameter. The caller is responsible for properly allocating and
573  * freeing it.
574  *
575  * When registering a callback, the transaction must be already created, but
576  * it cannot be committed or aborted. It can be assigned to a txg or not.
577  *
578  * The callback will be called after the transaction has been safely written
579  * to stable storage and will also be called if the dmu_tx is aborted.
580  * If there is any error which prevents the transaction from being committed to
581  * disk, the callback will be called with a value of error != 0.
582  */
583 typedef void dmu_tx_callback_func_t(void *dcb_data, int error);
584 
585 void dmu_tx_callback_register(dmu_tx_t *tx, dmu_tx_callback_func_t *dcb_func,
586     void *dcb_data);
587 
588 /*
589  * Free up the data blocks for a defined range of a file.  If size is
590  * -1, the range from offset to end-of-file is freed.
591  */
592 int dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
593 	uint64_t size, dmu_tx_t *tx);
594 int dmu_free_long_range(objset_t *os, uint64_t object, uint64_t offset,
595 	uint64_t size);
596 int dmu_free_long_object(objset_t *os, uint64_t object);
597 
598 /*
599  * Convenience functions.
600  *
601  * Canfail routines will return 0 on success, or an errno if there is a
602  * nonrecoverable I/O error.
603  */
604 #define	DMU_READ_PREFETCH	0 /* prefetch */
605 #define	DMU_READ_NO_PREFETCH	1 /* don't prefetch */
606 int dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
607 	void *buf, uint32_t flags);
608 void dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
609 	const void *buf, dmu_tx_t *tx);
610 void dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
611 	dmu_tx_t *tx);
612 int dmu_read_uio(objset_t *os, uint64_t object, struct uio *uio, uint64_t size);
613 int dmu_read_uio_dbuf(dmu_buf_t *zdb, struct uio *uio, uint64_t size);
614 int dmu_write_uio(objset_t *os, uint64_t object, struct uio *uio, uint64_t size,
615     dmu_tx_t *tx);
616 int dmu_write_uio_dbuf(dmu_buf_t *zdb, struct uio *uio, uint64_t size,
617     dmu_tx_t *tx);
618 #ifdef _KERNEL
619 #ifdef sun
620 int dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset,
621     uint64_t size, struct page *pp, dmu_tx_t *tx);
622 #else
623 int dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset,
624     uint64_t size, struct vm_page **ppa, dmu_tx_t *tx);
625 #endif
626 #endif
627 struct arc_buf *dmu_request_arcbuf(dmu_buf_t *handle, int size);
628 void dmu_return_arcbuf(struct arc_buf *buf);
629 void dmu_assign_arcbuf(dmu_buf_t *handle, uint64_t offset, struct arc_buf *buf,
630     dmu_tx_t *tx);
631 int dmu_xuio_init(struct xuio *uio, int niov);
632 void dmu_xuio_fini(struct xuio *uio);
633 int dmu_xuio_add(struct xuio *uio, struct arc_buf *abuf, offset_t off,
634     size_t n);
635 int dmu_xuio_cnt(struct xuio *uio);
636 struct arc_buf *dmu_xuio_arcbuf(struct xuio *uio, int i);
637 void dmu_xuio_clear(struct xuio *uio, int i);
638 void xuio_stat_wbuf_copied();
639 void xuio_stat_wbuf_nocopy();
640 
641 extern int zfs_prefetch_disable;
642 extern int zfs_max_recordsize;
643 
644 /*
645  * Asynchronously try to read in the data.
646  */
647 void dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset,
648     uint64_t len);
649 
650 typedef struct dmu_object_info {
651 	/* All sizes are in bytes unless otherwise indicated. */
652 	uint32_t doi_data_block_size;
653 	uint32_t doi_metadata_block_size;
654 	dmu_object_type_t doi_type;
655 	dmu_object_type_t doi_bonus_type;
656 	uint64_t doi_bonus_size;
657 	uint8_t doi_indirection;		/* 2 = dnode->indirect->data */
658 	uint8_t doi_checksum;
659 	uint8_t doi_compress;
660 	uint8_t doi_nblkptr;
661 	uint8_t doi_pad[4];
662 	uint64_t doi_physical_blocks_512;	/* data + metadata, 512b blks */
663 	uint64_t doi_max_offset;
664 	uint64_t doi_fill_count;		/* number of non-empty blocks */
665 } dmu_object_info_t;
666 
667 typedef void arc_byteswap_func_t(void *buf, size_t size);
668 
669 typedef struct dmu_object_type_info {
670 	dmu_object_byteswap_t	ot_byteswap;
671 	boolean_t		ot_metadata;
672 	char			*ot_name;
673 } dmu_object_type_info_t;
674 
675 typedef struct dmu_object_byteswap_info {
676 	arc_byteswap_func_t	*ob_func;
677 	char			*ob_name;
678 } dmu_object_byteswap_info_t;
679 
680 extern const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES];
681 extern const dmu_object_byteswap_info_t dmu_ot_byteswap[DMU_BSWAP_NUMFUNCS];
682 
683 /*
684  * Get information on a DMU object.
685  *
686  * Return 0 on success or ENOENT if object is not allocated.
687  *
688  * If doi is NULL, just indicates whether the object exists.
689  */
690 int dmu_object_info(objset_t *os, uint64_t object, dmu_object_info_t *doi);
691 /* Like dmu_object_info, but faster if you have a held dnode in hand. */
692 void dmu_object_info_from_dnode(struct dnode *dn, dmu_object_info_t *doi);
693 /* Like dmu_object_info, but faster if you have a held dbuf in hand. */
694 void dmu_object_info_from_db(dmu_buf_t *db, dmu_object_info_t *doi);
695 /*
696  * Like dmu_object_info_from_db, but faster still when you only care about
697  * the size.  This is specifically optimized for zfs_getattr().
698  */
699 void dmu_object_size_from_db(dmu_buf_t *db, uint32_t *blksize,
700     u_longlong_t *nblk512);
701 
702 typedef struct dmu_objset_stats {
703 	uint64_t dds_num_clones; /* number of clones of this */
704 	uint64_t dds_creation_txg;
705 	uint64_t dds_guid;
706 	dmu_objset_type_t dds_type;
707 	uint8_t dds_is_snapshot;
708 	uint8_t dds_inconsistent;
709 	char dds_origin[MAXNAMELEN];
710 } dmu_objset_stats_t;
711 
712 /*
713  * Get stats on a dataset.
714  */
715 void dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat);
716 
717 /*
718  * Add entries to the nvlist for all the objset's properties.  See
719  * zfs_prop_table[] and zfs(1m) for details on the properties.
720  */
721 void dmu_objset_stats(objset_t *os, struct nvlist *nv);
722 
723 /*
724  * Get the space usage statistics for statvfs().
725  *
726  * refdbytes is the amount of space "referenced" by this objset.
727  * availbytes is the amount of space available to this objset, taking
728  * into account quotas & reservations, assuming that no other objsets
729  * use the space first.  These values correspond to the 'referenced' and
730  * 'available' properties, described in the zfs(1m) manpage.
731  *
732  * usedobjs and availobjs are the number of objects currently allocated,
733  * and available.
734  */
735 void dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
736     uint64_t *usedobjsp, uint64_t *availobjsp);
737 
738 /*
739  * The fsid_guid is a 56-bit ID that can change to avoid collisions.
740  * (Contrast with the ds_guid which is a 64-bit ID that will never
741  * change, so there is a small probability that it will collide.)
742  */
743 uint64_t dmu_objset_fsid_guid(objset_t *os);
744 
745 /*
746  * Get the [cm]time for an objset's snapshot dir
747  */
748 timestruc_t dmu_objset_snap_cmtime(objset_t *os);
749 
750 int dmu_objset_is_snapshot(objset_t *os);
751 
752 extern struct spa *dmu_objset_spa(objset_t *os);
753 extern struct zilog *dmu_objset_zil(objset_t *os);
754 extern struct dsl_pool *dmu_objset_pool(objset_t *os);
755 extern struct dsl_dataset *dmu_objset_ds(objset_t *os);
756 extern void dmu_objset_name(objset_t *os, char *buf);
757 extern dmu_objset_type_t dmu_objset_type(objset_t *os);
758 extern uint64_t dmu_objset_id(objset_t *os);
759 extern zfs_sync_type_t dmu_objset_syncprop(objset_t *os);
760 extern zfs_logbias_op_t dmu_objset_logbias(objset_t *os);
761 extern int dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
762     uint64_t *id, uint64_t *offp, boolean_t *case_conflict);
763 extern int dmu_snapshot_realname(objset_t *os, char *name, char *real,
764     int maxlen, boolean_t *conflict);
765 extern int dmu_dir_list_next(objset_t *os, int namelen, char *name,
766     uint64_t *idp, uint64_t *offp);
767 
768 typedef int objset_used_cb_t(dmu_object_type_t bonustype,
769     void *bonus, uint64_t *userp, uint64_t *groupp);
770 extern void dmu_objset_register_type(dmu_objset_type_t ost,
771     objset_used_cb_t *cb);
772 extern void dmu_objset_set_user(objset_t *os, void *user_ptr);
773 extern void *dmu_objset_get_user(objset_t *os);
774 
775 /*
776  * Return the txg number for the given assigned transaction.
777  */
778 uint64_t dmu_tx_get_txg(dmu_tx_t *tx);
779 
780 /*
781  * Synchronous write.
782  * If a parent zio is provided this function initiates a write on the
783  * provided buffer as a child of the parent zio.
784  * In the absence of a parent zio, the write is completed synchronously.
785  * At write completion, blk is filled with the bp of the written block.
786  * Note that while the data covered by this function will be on stable
787  * storage when the write completes this new data does not become a
788  * permanent part of the file until the associated transaction commits.
789  */
790 
791 /*
792  * {zfs,zvol,ztest}_get_done() args
793  */
794 typedef struct zgd {
795 	struct zilog	*zgd_zilog;
796 	struct blkptr	*zgd_bp;
797 	dmu_buf_t	*zgd_db;
798 	struct rl	*zgd_rl;
799 	void		*zgd_private;
800 } zgd_t;
801 
802 typedef void dmu_sync_cb_t(zgd_t *arg, int error);
803 int dmu_sync(struct zio *zio, uint64_t txg, dmu_sync_cb_t *done, zgd_t *zgd);
804 
805 /*
806  * Find the next hole or data block in file starting at *off
807  * Return found offset in *off. Return ESRCH for end of file.
808  */
809 int dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole,
810     uint64_t *off);
811 
812 /*
813  * Initial setup and final teardown.
814  */
815 extern void dmu_init(void);
816 extern void dmu_fini(void);
817 
818 typedef void (*dmu_traverse_cb_t)(objset_t *os, void *arg, struct blkptr *bp,
819     uint64_t object, uint64_t offset, int len);
820 void dmu_traverse_objset(objset_t *os, uint64_t txg_start,
821     dmu_traverse_cb_t cb, void *arg);
822 int dmu_diff(const char *tosnap_name, const char *fromsnap_name,
823     struct file *fp, offset_t *offp);
824 
825 /* CRC64 table */
826 #define	ZFS_CRC64_POLY	0xC96C5795D7870F42ULL	/* ECMA-182, reflected form */
827 extern uint64_t zfs_crc64_table[256];
828 
829 extern int zfs_mdcomp_disable;
830 
831 #ifdef	__cplusplus
832 }
833 #endif
834 
835 #endif	/* _SYS_DMU_H */
836