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 */