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      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 2009 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 /*
     30  * This file describes the interface that the DMU provides for its
     31  * consumers.
     32  *
     33  * The DMU also interacts with the SPA.  That interface is described in
     34  * dmu_spa.h.
     35  */
     36 
     37 #include <sys/inttypes.h>
     38 #include <sys/types.h>
     39 #include <sys/param.h>
     40 #include <sys/cred.h>
     41 #include <sys/time.h>
     42 
     43 #ifdef	__cplusplus
     44 extern "C" {
     45 #endif
     46 
     47 struct uio;
     48 struct page;
     49 struct vnode;
     50 struct spa;
     51 struct zilog;
     52 struct zio;
     53 struct blkptr;
     54 struct zap_cursor;
     55 struct dsl_dataset;
     56 struct dsl_pool;
     57 struct dnode;
     58 struct drr_begin;
     59 struct drr_end;
     60 struct zbookmark;
     61 struct spa;
     62 struct nvlist;
     63 struct arc_buf;
     64 struct zio_prop;
     65 
     66 typedef struct objset objset_t;
     67 typedef struct dmu_tx dmu_tx_t;
     68 typedef struct dsl_dir dsl_dir_t;
     69 
     70 typedef enum dmu_object_type {
     71 	DMU_OT_NONE,
     72 	/* general: */
     73 	DMU_OT_OBJECT_DIRECTORY,	/* ZAP */
     74 	DMU_OT_OBJECT_ARRAY,		/* UINT64 */
     75 	DMU_OT_PACKED_NVLIST,		/* UINT8 (XDR by nvlist_pack/unpack) */
     76 	DMU_OT_PACKED_NVLIST_SIZE,	/* UINT64 */
     77 	DMU_OT_BPLIST,			/* UINT64 */
     78 	DMU_OT_BPLIST_HDR,		/* UINT64 */
     79 	/* spa: */
     80 	DMU_OT_SPACE_MAP_HEADER,	/* UINT64 */
     81 	DMU_OT_SPACE_MAP,		/* UINT64 */
     82 	/* zil: */
     83 	DMU_OT_INTENT_LOG,		/* UINT64 */
     84 	/* dmu: */
     85 	DMU_OT_DNODE,			/* DNODE */
     86 	DMU_OT_OBJSET,			/* OBJSET */
     87 	/* dsl: */
     88 	DMU_OT_DSL_DIR,			/* UINT64 */
     89 	DMU_OT_DSL_DIR_CHILD_MAP,	/* ZAP */
     90 	DMU_OT_DSL_DS_SNAP_MAP,		/* ZAP */
     91 	DMU_OT_DSL_PROPS,		/* ZAP */
     92 	DMU_OT_DSL_DATASET,		/* UINT64 */
     93 	/* zpl: */
     94 	DMU_OT_ZNODE,			/* ZNODE */
     95 	DMU_OT_OLDACL,			/* Old ACL */
     96 	DMU_OT_PLAIN_FILE_CONTENTS,	/* UINT8 */
     97 	DMU_OT_DIRECTORY_CONTENTS,	/* ZAP */
     98 	DMU_OT_MASTER_NODE,		/* ZAP */
     99 	DMU_OT_UNLINKED_SET,		/* ZAP */
    100 	/* zvol: */
    101 	DMU_OT_ZVOL,			/* UINT8 */
    102 	DMU_OT_ZVOL_PROP,		/* ZAP */
    103 	/* other; for testing only! */
    104 	DMU_OT_PLAIN_OTHER,		/* UINT8 */
    105 	DMU_OT_UINT64_OTHER,		/* UINT64 */
    106 	DMU_OT_ZAP_OTHER,		/* ZAP */
    107 	/* new object types: */
    108 	DMU_OT_ERROR_LOG,		/* ZAP */
    109 	DMU_OT_SPA_HISTORY,		/* UINT8 */
    110 	DMU_OT_SPA_HISTORY_OFFSETS,	/* spa_his_phys_t */
    111 	DMU_OT_POOL_PROPS,		/* ZAP */
    112 	DMU_OT_DSL_PERMS,		/* ZAP */
    113 	DMU_OT_ACL,			/* ACL */
    114 	DMU_OT_SYSACL,			/* SYSACL */
    115 	DMU_OT_FUID,			/* FUID table (Packed NVLIST UINT8) */
    116 	DMU_OT_FUID_SIZE,		/* FUID table size UINT64 */
    117 	DMU_OT_NEXT_CLONES,		/* ZAP */
    118 	DMU_OT_SCRUB_QUEUE,		/* ZAP */
    119 	DMU_OT_USERGROUP_USED,		/* ZAP */
    120 	DMU_OT_USERGROUP_QUOTA,		/* ZAP */
    121 	DMU_OT_USERREFS,		/* ZAP */
    122 	DMU_OT_DDT_ZAP,			/* ZAP */
    123 	DMU_OT_DDT_STATS,		/* ZAP */
    124 	DMU_OT_NUMTYPES
    125 } dmu_object_type_t;
    126 
    127 typedef enum dmu_objset_type {
    128 	DMU_OST_NONE,
    129 	DMU_OST_META,
    130 	DMU_OST_ZFS,
    131 	DMU_OST_ZVOL,
    132 	DMU_OST_OTHER,			/* For testing only! */
    133 	DMU_OST_ANY,			/* Be careful! */
    134 	DMU_OST_NUMTYPES
    135 } dmu_objset_type_t;
    136 
    137 void byteswap_uint64_array(void *buf, size_t size);
    138 void byteswap_uint32_array(void *buf, size_t size);
    139 void byteswap_uint16_array(void *buf, size_t size);
    140 void byteswap_uint8_array(void *buf, size_t size);
    141 void zap_byteswap(void *buf, size_t size);
    142 void zfs_oldacl_byteswap(void *buf, size_t size);
    143 void zfs_acl_byteswap(void *buf, size_t size);
    144 void zfs_znode_byteswap(void *buf, size_t size);
    145 
    146 #define	DS_FIND_SNAPSHOTS	(1<<0)
    147 #define	DS_FIND_CHILDREN	(1<<1)
    148 
    149 /*
    150  * The maximum number of bytes that can be accessed as part of one
    151  * operation, including metadata.
    152  */
    153 #define	DMU_MAX_ACCESS (10<<20) /* 10MB */
    154 #define	DMU_MAX_DELETEBLKCNT (20480) /* ~5MB of indirect blocks */
    155 
    156 #define	DMU_USERUSED_OBJECT	(-1ULL)
    157 #define	DMU_GROUPUSED_OBJECT	(-2ULL)
    158 #define	DMU_DEADLIST_OBJECT	(-3ULL)
    159 
    160 /*
    161  * Public routines to create, destroy, open, and close objsets.
    162  */
    163 int dmu_objset_hold(const char *name, void *tag, objset_t **osp);
    164 int dmu_objset_own(const char *name, dmu_objset_type_t type,
    165     boolean_t readonly, void *tag, objset_t **osp);
    166 void dmu_objset_rele(objset_t *os, void *tag);
    167 void dmu_objset_disown(objset_t *os, void *tag);
    168 int dmu_objset_open_ds(struct dsl_dataset *ds, objset_t **osp);
    169 
    170 int dmu_objset_evict_dbufs(objset_t *os);
    171 int dmu_objset_create(const char *name, dmu_objset_type_t type, uint64_t flags,
    172     void (*func)(objset_t *os, void *arg, cred_t *cr, dmu_tx_t *tx), void *arg);
    173 int dmu_objset_clone(const char *name, struct dsl_dataset *clone_origin,
    174     uint64_t flags);
    175 int dmu_objset_destroy(const char *name, boolean_t defer);
    176 int dmu_snapshots_destroy(char *fsname, char *snapname, boolean_t defer);
    177 int dmu_objset_snapshot(char *fsname, char *snapname, struct nvlist *props,
    178     boolean_t recursive);
    179 int dmu_objset_rename(const char *name, const char *newname,
    180     boolean_t recursive);
    181 int dmu_objset_find(char *name, int func(char *, void *), void *arg,
    182     int flags);
    183 void dmu_objset_byteswap(void *buf, size_t size);
    184 
    185 typedef struct dmu_buf {
    186 	uint64_t db_object;		/* object that this buffer is part of */
    187 	uint64_t db_offset;		/* byte offset in this object */
    188 	uint64_t db_size;		/* size of buffer in bytes */
    189 	void *db_data;			/* data in buffer */
    190 } dmu_buf_t;
    191 
    192 typedef void dmu_buf_evict_func_t(struct dmu_buf *db, void *user_ptr);
    193 
    194 /*
    195  * The names of zap entries in the DIRECTORY_OBJECT of the MOS.
    196  */
    197 #define	DMU_POOL_DIRECTORY_OBJECT	1
    198 #define	DMU_POOL_CONFIG			"config"
    199 #define	DMU_POOL_ROOT_DATASET		"root_dataset"
    200 #define	DMU_POOL_SYNC_BPLIST		"sync_bplist"
    201 #define	DMU_POOL_ERRLOG_SCRUB		"errlog_scrub"
    202 #define	DMU_POOL_ERRLOG_LAST		"errlog_last"
    203 #define	DMU_POOL_SPARES			"spares"
    204 #define	DMU_POOL_DEFLATE		"deflate"
    205 #define	DMU_POOL_HISTORY		"history"
    206 #define	DMU_POOL_PROPS			"pool_props"
    207 #define	DMU_POOL_L2CACHE		"l2cache"
    208 #define	DMU_POOL_TMP_USERREFS		"tmp_userrefs"
    209 #define	DMU_POOL_DDT			"DDT-%s-%s-%s"
    210 #define	DMU_POOL_DDT_STATS		"DDT-statistics"
    211 
    212 /* 4x8 zbookmark_t */
    213 #define	DMU_POOL_SCRUB_BOOKMARK		"scrub_bookmark"
    214 /* 4x8 ddt_bookmark_t */
    215 #define	DMU_POOL_SCRUB_DDT_BOOKMARK	"scrub_ddt_bookmark"
    216 /* 1x8 max_class */
    217 #define	DMU_POOL_SCRUB_DDT_CLASS_MAX	"scrub_ddt_class_max"
    218 /* 1x8 zap obj DMU_OT_SCRUB_QUEUE */
    219 #define	DMU_POOL_SCRUB_QUEUE		"scrub_queue"
    220 /* 1x8 txg */
    221 #define	DMU_POOL_SCRUB_MIN_TXG		"scrub_min_txg"
    222 /* 1x8 txg */
    223 #define	DMU_POOL_SCRUB_MAX_TXG		"scrub_max_txg"
    224 /* 1x4 enum scrub_func */
    225 #define	DMU_POOL_SCRUB_FUNC		"scrub_func"
    226 /* 1x8 count */
    227 #define	DMU_POOL_SCRUB_ERRORS		"scrub_errors"
    228 
    229 /*
    230  * Allocate an object from this objset.  The range of object numbers
    231  * available is (0, DN_MAX_OBJECT).  Object 0 is the meta-dnode.
    232  *
    233  * The transaction must be assigned to a txg.  The newly allocated
    234  * object will be "held" in the transaction (ie. you can modify the
    235  * newly allocated object in this transaction).
    236  *
    237  * dmu_object_alloc() chooses an object and returns it in *objectp.
    238  *
    239  * dmu_object_claim() allocates a specific object number.  If that
    240  * number is already allocated, it fails and returns EEXIST.
    241  *
    242  * Return 0 on success, or ENOSPC or EEXIST as specified above.
    243  */
    244 uint64_t dmu_object_alloc(objset_t *os, dmu_object_type_t ot,
    245     int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
    246 int dmu_object_claim(objset_t *os, uint64_t object, dmu_object_type_t ot,
    247     int blocksize, dmu_object_type_t bonus_type, int bonus_len, dmu_tx_t *tx);
    248 int dmu_object_reclaim(objset_t *os, uint64_t object, dmu_object_type_t ot,
    249     int blocksize, dmu_object_type_t bonustype, int bonuslen);
    250 
    251 /*
    252  * Free an object from this objset.
    253  *
    254  * The object's data will be freed as well (ie. you don't need to call
    255  * dmu_free(object, 0, -1, tx)).
    256  *
    257  * The object need not be held in the transaction.
    258  *
    259  * If there are any holds on this object's buffers (via dmu_buf_hold()),
    260  * or tx holds on the object (via dmu_tx_hold_object()), you can not
    261  * free it; it fails and returns EBUSY.
    262  *
    263  * If the object is not allocated, it fails and returns ENOENT.
    264  *
    265  * Return 0 on success, or EBUSY or ENOENT as specified above.
    266  */
    267 int dmu_object_free(objset_t *os, uint64_t object, dmu_tx_t *tx);
    268 
    269 /*
    270  * Find the next allocated or free object.
    271  *
    272  * The objectp parameter is in-out.  It will be updated to be the next
    273  * object which is allocated.  Ignore objects which have not been
    274  * modified since txg.
    275  *
    276  * XXX Can only be called on a objset with no dirty data.
    277  *
    278  * Returns 0 on success, or ENOENT if there are no more objects.
    279  */
    280 int dmu_object_next(objset_t *os, uint64_t *objectp,
    281     boolean_t hole, uint64_t txg);
    282 
    283 /*
    284  * Set the data blocksize for an object.
    285  *
    286  * The object cannot have any blocks allcated beyond the first.  If
    287  * the first block is allocated already, the new size must be greater
    288  * than the current block size.  If these conditions are not met,
    289  * ENOTSUP will be returned.
    290  *
    291  * Returns 0 on success, or EBUSY if there are any holds on the object
    292  * contents, or ENOTSUP as described above.
    293  */
    294 int dmu_object_set_blocksize(objset_t *os, uint64_t object, uint64_t size,
    295     int ibs, dmu_tx_t *tx);
    296 
    297 /*
    298  * Set the checksum property on a dnode.  The new checksum algorithm will
    299  * apply to all newly written blocks; existing blocks will not be affected.
    300  */
    301 void dmu_object_set_checksum(objset_t *os, uint64_t object, uint8_t checksum,
    302     dmu_tx_t *tx);
    303 
    304 /*
    305  * Set the compress property on a dnode.  The new compression algorithm will
    306  * apply to all newly written blocks; existing blocks will not be affected.
    307  */
    308 void dmu_object_set_compress(objset_t *os, uint64_t object, uint8_t compress,
    309     dmu_tx_t *tx);
    310 
    311 /*
    312  * Decide how to write a block: checksum, compression, number of copies, etc.
    313  */
    314 #define	WP_NOFILL	0x1
    315 #define	WP_DMU_SYNC	0x2
    316 
    317 void dmu_write_policy(objset_t *os, struct dnode *dn, int level, int wp,
    318     struct zio_prop *zp);
    319 /*
    320  * The bonus data is accessed more or less like a regular buffer.
    321  * You must dmu_bonus_hold() to get the buffer, which will give you a
    322  * dmu_buf_t with db_offset==-1ULL, and db_size = the size of the bonus
    323  * data.  As with any normal buffer, you must call dmu_buf_read() to
    324  * read db_data, dmu_buf_will_dirty() before modifying it, and the
    325  * object must be held in an assigned transaction before calling
    326  * dmu_buf_will_dirty.  You may use dmu_buf_set_user() on the bonus
    327  * buffer as well.  You must release your hold with dmu_buf_rele().
    328  */
    329 int dmu_bonus_hold(objset_t *os, uint64_t object, void *tag, dmu_buf_t **);
    330 int dmu_bonus_max(void);
    331 int dmu_set_bonus(dmu_buf_t *, int, dmu_tx_t *);
    332 
    333 /*
    334  * Obtain the DMU buffer from the specified object which contains the
    335  * specified offset.  dmu_buf_hold() puts a "hold" on the buffer, so
    336  * that it will remain in memory.  You must release the hold with
    337  * dmu_buf_rele().  You musn't access the dmu_buf_t after releasing your
    338  * hold.  You must have a hold on any dmu_buf_t* you pass to the DMU.
    339  *
    340  * You must call dmu_buf_read, dmu_buf_will_dirty, or dmu_buf_will_fill
    341  * on the returned buffer before reading or writing the buffer's
    342  * db_data.  The comments for those routines describe what particular
    343  * operations are valid after calling them.
    344  *
    345  * The object number must be a valid, allocated object number.
    346  */
    347 int dmu_buf_hold(objset_t *os, uint64_t object, uint64_t offset,
    348     void *tag, dmu_buf_t **);
    349 void dmu_buf_add_ref(dmu_buf_t *db, void* tag);
    350 void dmu_buf_rele(dmu_buf_t *db, void *tag);
    351 uint64_t dmu_buf_refcount(dmu_buf_t *db);
    352 
    353 /*
    354  * dmu_buf_hold_array holds the DMU buffers which contain all bytes in a
    355  * range of an object.  A pointer to an array of dmu_buf_t*'s is
    356  * returned (in *dbpp).
    357  *
    358  * dmu_buf_rele_array releases the hold on an array of dmu_buf_t*'s, and
    359  * frees the array.  The hold on the array of buffers MUST be released
    360  * with dmu_buf_rele_array.  You can NOT release the hold on each buffer
    361  * individually with dmu_buf_rele.
    362  */
    363 int dmu_buf_hold_array_by_bonus(dmu_buf_t *db, uint64_t offset,
    364     uint64_t length, int read, void *tag, int *numbufsp, dmu_buf_t ***dbpp);
    365 void dmu_buf_rele_array(dmu_buf_t **, int numbufs, void *tag);
    366 
    367 /*
    368  * Returns NULL on success, or the existing user ptr if it's already
    369  * been set.
    370  *
    371  * user_ptr is for use by the user and can be obtained via dmu_buf_get_user().
    372  *
    373  * user_data_ptr_ptr should be NULL, or a pointer to a pointer which
    374  * will be set to db->db_data when you are allowed to access it.  Note
    375  * that db->db_data (the pointer) can change when you do dmu_buf_read(),
    376  * dmu_buf_tryupgrade(), dmu_buf_will_dirty(), or dmu_buf_will_fill().
    377  * *user_data_ptr_ptr will be set to the new value when it changes.
    378  *
    379  * If non-NULL, pageout func will be called when this buffer is being
    380  * excised from the cache, so that you can clean up the data structure
    381  * pointed to by user_ptr.
    382  *
    383  * dmu_evict_user() will call the pageout func for all buffers in a
    384  * objset with a given pageout func.
    385  */
    386 void *dmu_buf_set_user(dmu_buf_t *db, void *user_ptr, void *user_data_ptr_ptr,
    387     dmu_buf_evict_func_t *pageout_func);
    388 /*
    389  * set_user_ie is the same as set_user, but request immediate eviction
    390  * when hold count goes to zero.
    391  */
    392 void *dmu_buf_set_user_ie(dmu_buf_t *db, void *user_ptr,
    393     void *user_data_ptr_ptr, dmu_buf_evict_func_t *pageout_func);
    394 void *dmu_buf_update_user(dmu_buf_t *db_fake, void *old_user_ptr,
    395     void *user_ptr, void *user_data_ptr_ptr,
    396     dmu_buf_evict_func_t *pageout_func);
    397 void dmu_evict_user(objset_t *os, dmu_buf_evict_func_t *func);
    398 
    399 /*
    400  * Returns the user_ptr set with dmu_buf_set_user(), or NULL if not set.
    401  */
    402 void *dmu_buf_get_user(dmu_buf_t *db);
    403 
    404 /*
    405  * Indicate that you are going to modify the buffer's data (db_data).
    406  *
    407  * The transaction (tx) must be assigned to a txg (ie. you've called
    408  * dmu_tx_assign()).  The buffer's object must be held in the tx
    409  * (ie. you've called dmu_tx_hold_object(tx, db->db_object)).
    410  */
    411 void dmu_buf_will_dirty(dmu_buf_t *db, dmu_tx_t *tx);
    412 
    413 /*
    414  * Tells if the given dbuf is freeable.
    415  */
    416 boolean_t dmu_buf_freeable(dmu_buf_t *);
    417 
    418 /*
    419  * You must create a transaction, then hold the objects which you will
    420  * (or might) modify as part of this transaction.  Then you must assign
    421  * the transaction to a transaction group.  Once the transaction has
    422  * been assigned, you can modify buffers which belong to held objects as
    423  * part of this transaction.  You can't modify buffers before the
    424  * transaction has been assigned; you can't modify buffers which don't
    425  * belong to objects which this transaction holds; you can't hold
    426  * objects once the transaction has been assigned.  You may hold an
    427  * object which you are going to free (with dmu_object_free()), but you
    428  * don't have to.
    429  *
    430  * You can abort the transaction before it has been assigned.
    431  *
    432  * Note that you may hold buffers (with dmu_buf_hold) at any time,
    433  * regardless of transaction state.
    434  */
    435 
    436 #define	DMU_NEW_OBJECT	(-1ULL)
    437 #define	DMU_OBJECT_END	(-1ULL)
    438 
    439 dmu_tx_t *dmu_tx_create(objset_t *os);
    440 void dmu_tx_hold_write(dmu_tx_t *tx, uint64_t object, uint64_t off, int len);
    441 void dmu_tx_hold_free(dmu_tx_t *tx, uint64_t object, uint64_t off,
    442     uint64_t len);
    443 void dmu_tx_hold_zap(dmu_tx_t *tx, uint64_t object, int add, const char *name);
    444 void dmu_tx_hold_bonus(dmu_tx_t *tx, uint64_t object);
    445 void dmu_tx_abort(dmu_tx_t *tx);
    446 int dmu_tx_assign(dmu_tx_t *tx, uint64_t txg_how);
    447 void dmu_tx_wait(dmu_tx_t *tx);
    448 void dmu_tx_commit(dmu_tx_t *tx);
    449 
    450 /*
    451  * To register a commit callback, dmu_tx_callback_register() must be called.
    452  *
    453  * dcb_data is a pointer to caller private data that is passed on as a
    454  * callback parameter. The caller is responsible for properly allocating and
    455  * freeing it.
    456  *
    457  * When registering a callback, the transaction must be already created, but
    458  * it cannot be committed or aborted. It can be assigned to a txg or not.
    459  *
    460  * The callback will be called after the transaction has been safely written
    461  * to stable storage and will also be called if the dmu_tx is aborted.
    462  * If there is any error which prevents the transaction from being committed to
    463  * disk, the callback will be called with a value of error != 0.
    464  */
    465 typedef void dmu_tx_callback_func_t(void *dcb_data, int error);
    466 
    467 void dmu_tx_callback_register(dmu_tx_t *tx, dmu_tx_callback_func_t *dcb_func,
    468     void *dcb_data);
    469 
    470 /*
    471  * Free up the data blocks for a defined range of a file.  If size is
    472  * zero, the range from offset to end-of-file is freed.
    473  */
    474 int dmu_free_range(objset_t *os, uint64_t object, uint64_t offset,
    475 	uint64_t size, dmu_tx_t *tx);
    476 int dmu_free_long_range(objset_t *os, uint64_t object, uint64_t offset,
    477 	uint64_t size);
    478 int dmu_free_object(objset_t *os, uint64_t object);
    479 
    480 /*
    481  * Convenience functions.
    482  *
    483  * Canfail routines will return 0 on success, or an errno if there is a
    484  * nonrecoverable I/O error.
    485  */
    486 #define	DMU_READ_PREFETCH	0 /* prefetch */
    487 #define	DMU_READ_NO_PREFETCH	1 /* don't prefetch */
    488 int dmu_read(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
    489 	void *buf, uint32_t flags);
    490 void dmu_write(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
    491 	const void *buf, dmu_tx_t *tx);
    492 void dmu_prealloc(objset_t *os, uint64_t object, uint64_t offset, uint64_t size,
    493 	dmu_tx_t *tx);
    494 int dmu_read_uio(objset_t *os, uint64_t object, struct uio *uio, uint64_t size);
    495 int dmu_write_uio(objset_t *os, uint64_t object, struct uio *uio, uint64_t size,
    496     dmu_tx_t *tx);
    497 int dmu_write_pages(objset_t *os, uint64_t object, uint64_t offset,
    498     uint64_t size, struct page *pp, dmu_tx_t *tx);
    499 struct arc_buf *dmu_request_arcbuf(dmu_buf_t *handle, int size);
    500 void dmu_return_arcbuf(struct arc_buf *buf);
    501 void dmu_assign_arcbuf(dmu_buf_t *handle, uint64_t offset, struct arc_buf *buf,
    502     dmu_tx_t *tx);
    503 
    504 extern int zfs_prefetch_disable;
    505 
    506 /*
    507  * Asynchronously try to read in the data.
    508  */
    509 void dmu_prefetch(objset_t *os, uint64_t object, uint64_t offset,
    510     uint64_t len);
    511 
    512 typedef struct dmu_object_info {
    513 	/* All sizes are in bytes unless otherwise indicated. */
    514 	uint32_t doi_data_block_size;
    515 	uint32_t doi_metadata_block_size;
    516 	dmu_object_type_t doi_type;
    517 	dmu_object_type_t doi_bonus_type;
    518 	uint64_t doi_bonus_size;
    519 	uint8_t doi_indirection;		/* 2 = dnode->indirect->data */
    520 	uint8_t doi_checksum;
    521 	uint8_t doi_compress;
    522 	uint8_t doi_pad[5];
    523 	uint64_t doi_physical_blocks_512;	/* data + metadata, 512b blks */
    524 	uint64_t doi_max_offset;
    525 	uint64_t doi_fill_count;		/* number of non-empty blocks */
    526 } dmu_object_info_t;
    527 
    528 typedef void arc_byteswap_func_t(void *buf, size_t size);
    529 
    530 typedef struct dmu_object_type_info {
    531 	arc_byteswap_func_t	*ot_byteswap;
    532 	boolean_t		ot_metadata;
    533 	char			*ot_name;
    534 } dmu_object_type_info_t;
    535 
    536 extern const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES];
    537 
    538 /*
    539  * Get information on a DMU object.
    540  *
    541  * Return 0 on success or ENOENT if object is not allocated.
    542  *
    543  * If doi is NULL, just indicates whether the object exists.
    544  */
    545 int dmu_object_info(objset_t *os, uint64_t object, dmu_object_info_t *doi);
    546 void dmu_object_info_from_dnode(struct dnode *dn, dmu_object_info_t *doi);
    547 void dmu_object_info_from_db(dmu_buf_t *db, dmu_object_info_t *doi);
    548 void dmu_object_size_from_db(dmu_buf_t *db, uint32_t *blksize,
    549     u_longlong_t *nblk512);
    550 
    551 typedef struct dmu_objset_stats {
    552 	uint64_t dds_num_clones; /* number of clones of this */
    553 	uint64_t dds_creation_txg;
    554 	uint64_t dds_guid;
    555 	dmu_objset_type_t dds_type;
    556 	uint8_t dds_is_snapshot;
    557 	uint8_t dds_inconsistent;
    558 	char dds_origin[MAXNAMELEN];
    559 } dmu_objset_stats_t;
    560 
    561 /*
    562  * Get stats on a dataset.
    563  */
    564 void dmu_objset_fast_stat(objset_t *os, dmu_objset_stats_t *stat);
    565 
    566 /*
    567  * Add entries to the nvlist for all the objset's properties.  See
    568  * zfs_prop_table[] and zfs(1m) for details on the properties.
    569  */
    570 void dmu_objset_stats(objset_t *os, struct nvlist *nv);
    571 
    572 /*
    573  * Get the space usage statistics for statvfs().
    574  *
    575  * refdbytes is the amount of space "referenced" by this objset.
    576  * availbytes is the amount of space available to this objset, taking
    577  * into account quotas & reservations, assuming that no other objsets
    578  * use the space first.  These values correspond to the 'referenced' and
    579  * 'available' properties, described in the zfs(1m) manpage.
    580  *
    581  * usedobjs and availobjs are the number of objects currently allocated,
    582  * and available.
    583  */
    584 void dmu_objset_space(objset_t *os, uint64_t *refdbytesp, uint64_t *availbytesp,
    585     uint64_t *usedobjsp, uint64_t *availobjsp);
    586 
    587 /*
    588  * The fsid_guid is a 56-bit ID that can change to avoid collisions.
    589  * (Contrast with the ds_guid which is a 64-bit ID that will never
    590  * change, so there is a small probability that it will collide.)
    591  */
    592 uint64_t dmu_objset_fsid_guid(objset_t *os);
    593 
    594 /*
    595  * Get the [cm]time for an objset's snapshot dir
    596  */
    597 timestruc_t dmu_objset_snap_cmtime(objset_t *os);
    598 
    599 int dmu_objset_is_snapshot(objset_t *os);
    600 
    601 extern struct spa *dmu_objset_spa(objset_t *os);
    602 extern struct zilog *dmu_objset_zil(objset_t *os);
    603 extern struct dsl_pool *dmu_objset_pool(objset_t *os);
    604 extern struct dsl_dataset *dmu_objset_ds(objset_t *os);
    605 extern void dmu_objset_name(objset_t *os, char *buf);
    606 extern dmu_objset_type_t dmu_objset_type(objset_t *os);
    607 extern uint64_t dmu_objset_id(objset_t *os);
    608 extern uint64_t dmu_objset_logbias(objset_t *os);
    609 extern int dmu_snapshot_list_next(objset_t *os, int namelen, char *name,
    610     uint64_t *id, uint64_t *offp, boolean_t *case_conflict);
    611 extern int dmu_snapshot_realname(objset_t *os, char *name, char *real,
    612     int maxlen, boolean_t *conflict);
    613 extern int dmu_dir_list_next(objset_t *os, int namelen, char *name,
    614     uint64_t *idp, uint64_t *offp);
    615 
    616 typedef int objset_used_cb_t(dmu_object_type_t bonustype,
    617     void *bonus, uint64_t *userp, uint64_t *groupp);
    618 extern void dmu_objset_register_type(dmu_objset_type_t ost,
    619     objset_used_cb_t *cb);
    620 extern void dmu_objset_set_user(objset_t *os, void *user_ptr);
    621 extern void *dmu_objset_get_user(objset_t *os);
    622 
    623 /*
    624  * Return the txg number for the given assigned transaction.
    625  */
    626 uint64_t dmu_tx_get_txg(dmu_tx_t *tx);
    627 
    628 /*
    629  * Synchronous write.
    630  * If a parent zio is provided this function initiates a write on the
    631  * provided buffer as a child of the parent zio.
    632  * In the absence of a parent zio, the write is completed synchronously.
    633  * At write completion, blk is filled with the bp of the written block.
    634  * Note that while the data covered by this function will be on stable
    635  * storage when the write completes this new data does not become a
    636  * permanent part of the file until the associated transaction commits.
    637  */
    638 
    639 /*
    640  * {zfs,zvol,ztest}_get_done() args
    641  */
    642 typedef struct zgd {
    643 	struct zilog	*zgd_zilog;
    644 	struct blkptr	*zgd_bp;
    645 	dmu_buf_t	*zgd_db;
    646 	struct rl	*zgd_rl;
    647 	void		*zgd_private;
    648 } zgd_t;
    649 
    650 typedef void dmu_sync_cb_t(zgd_t *arg, int error);
    651 int dmu_sync(struct zio *zio, uint64_t txg, dmu_sync_cb_t *done, zgd_t *zgd);
    652 
    653 /*
    654  * Find the next hole or data block in file starting at *off
    655  * Return found offset in *off. Return ESRCH for end of file.
    656  */
    657 int dmu_offset_next(objset_t *os, uint64_t object, boolean_t hole,
    658     uint64_t *off);
    659 
    660 /*
    661  * Initial setup and final teardown.
    662  */
    663 extern void dmu_init(void);
    664 extern void dmu_fini(void);
    665 
    666 typedef void (*dmu_traverse_cb_t)(objset_t *os, void *arg, struct blkptr *bp,
    667     uint64_t object, uint64_t offset, int len);
    668 void dmu_traverse_objset(objset_t *os, uint64_t txg_start,
    669     dmu_traverse_cb_t cb, void *arg);
    670 
    671 int dmu_sendbackup(objset_t *tosnap, objset_t *fromsnap, boolean_t fromorigin,
    672     struct vnode *vp, offset_t *off);
    673 
    674 typedef struct dmu_recv_cookie {
    675 	/*
    676 	 * This structure is opaque!
    677 	 *
    678 	 * If logical and real are different, we are recving the stream
    679 	 * into the "real" temporary clone, and then switching it with
    680 	 * the "logical" target.
    681 	 */
    682 	struct dsl_dataset *drc_logical_ds;
    683 	struct dsl_dataset *drc_real_ds;
    684 	struct drr_begin *drc_drrb;
    685 	char *drc_tosnap;
    686 	char *drc_top_ds;
    687 	boolean_t drc_newfs;
    688 	boolean_t drc_force;
    689 } dmu_recv_cookie_t;
    690 
    691 int dmu_recv_begin(char *tofs, char *tosnap, char *topds, struct drr_begin *,
    692     boolean_t force, objset_t *origin, dmu_recv_cookie_t *);
    693 int dmu_recv_stream(dmu_recv_cookie_t *drc, struct vnode *vp, offset_t *voffp);
    694 int dmu_recv_end(dmu_recv_cookie_t *drc);
    695 
    696 /* CRC64 table */
    697 #define	ZFS_CRC64_POLY	0xC96C5795D7870F42ULL	/* ECMA-182, reflected form */
    698 extern uint64_t zfs_crc64_table[256];
    699 
    700 #ifdef	__cplusplus
    701 }
    702 #endif
    703 
    704 #endif	/* _SYS_DMU_H */
    705