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) 2012, 2018 by Delphix. All rights reserved.
  24  * Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
  25  */
  26 
  27 #ifndef _SYS_DNODE_H
  28 #define _SYS_DNODE_H
  29 
  30 #include <sys/zfs_context.h>
  31 #include <sys/avl.h>
  32 #include <sys/spa.h>
  33 #include <sys/txg.h>
  34 #include <sys/zio.h>
  35 #include <sys/refcount.h>
  36 #include <sys/dmu_zfetch.h>
  37 #include <sys/zrlock.h>
  38 #include <sys/multilist.h>
  39 
  40 #ifdef  __cplusplus
  41 extern "C" {
  42 #endif
  43 
  44 /*
  45  * dnode_hold() flags.
  46  */
  47 #define DNODE_MUST_BE_ALLOCATED 1
  48 #define DNODE_MUST_BE_FREE      2
  49 #define DNODE_DRY_RUN           4
  50 
  51 /*
  52  * dnode_next_offset() flags.
  53  */
  54 #define DNODE_FIND_HOLE         1
  55 #define DNODE_FIND_BACKWARDS    2
  56 #define DNODE_FIND_HAVELOCK     4
  57 
  58 /*
  59  * Fixed constants.
  60  */
  61 #define DNODE_SHIFT             9       /* 512 bytes */
  62 #define DN_MIN_INDBLKSHIFT      12      /* 4k */
  63 /*
  64  * If we ever increase this value beyond 20, we need to revisit all logic that
  65  * does x << level * ebps to handle overflow.  With a 1M indirect block size,
  66  * 4 levels of indirect blocks would not be able to guarantee addressing an
  67  * entire object, so 5 levels will be used, but 5 * (20 - 7) = 65.
  68  */
  69 #define DN_MAX_INDBLKSHIFT      17      /* 128k */
  70 #define DNODE_BLOCK_SHIFT       14      /* 16k */
  71 #define DNODE_CORE_SIZE         64      /* 64 bytes for dnode sans blkptrs */
  72 #define DN_MAX_OBJECT_SHIFT     48      /* 256 trillion (zfs_fid_t limit) */
  73 #define DN_MAX_OFFSET_SHIFT     64      /* 2^64 bytes in a dnode */
  74 
  75 /*
  76  * dnode id flags
  77  *
  78  * Note: a file will never ever have its ids moved from bonus->spill
  79  */
  80 #define DN_ID_CHKED_BONUS       0x1
  81 #define DN_ID_CHKED_SPILL       0x2
  82 #define DN_ID_OLD_EXIST         0x4
  83 #define DN_ID_NEW_EXIST         0x8
  84 
  85 /*
  86  * Derived constants.
  87  */
  88 #define DNODE_MIN_SIZE          (1 << DNODE_SHIFT)
  89 #define DNODE_MAX_SIZE          (1 << DNODE_BLOCK_SHIFT)
  90 #define DNODE_BLOCK_SIZE        (1 << DNODE_BLOCK_SHIFT)
  91 #define DNODE_MIN_SLOTS         (DNODE_MIN_SIZE >> DNODE_SHIFT)
  92 #define DNODE_MAX_SLOTS         (DNODE_MAX_SIZE >> DNODE_SHIFT)
  93 #define DN_BONUS_SIZE(dnsize)   ((dnsize) - DNODE_CORE_SIZE - \
  94         (1 << SPA_BLKPTRSHIFT))
  95 #define DN_SLOTS_TO_BONUSLEN(slots)     DN_BONUS_SIZE((slots) << DNODE_SHIFT)
  96 #define DN_OLD_MAX_BONUSLEN     (DN_BONUS_SIZE(DNODE_MIN_SIZE))
  97 #define DN_MAX_NBLKPTR  ((DNODE_MIN_SIZE - DNODE_CORE_SIZE) >> SPA_BLKPTRSHIFT)
  98 #define DN_MAX_OBJECT           (1ULL << DN_MAX_OBJECT_SHIFT)
  99 #define DN_ZERO_BONUSLEN        (DN_BONUS_SIZE(DNODE_MAX_SIZE) + 1)
 100 #define DN_KILL_SPILLBLK        (1)
 101 
 102 #define DN_SLOT_UNINIT          ((void *)NULL)  /* Uninitialized */
 103 #define DN_SLOT_FREE            ((void *)1UL)   /* Free slot */
 104 #define DN_SLOT_ALLOCATED       ((void *)2UL)   /* Allocated slot */
 105 #define DN_SLOT_INTERIOR        ((void *)3UL)   /* Interior allocated slot */
 106 #define DN_SLOT_IS_PTR(dn)      ((void *)dn > DN_SLOT_INTERIOR)
 107 #define DN_SLOT_IS_VALID(dn)    ((void *)dn != NULL)
 108 
 109 #define DNODES_PER_BLOCK_SHIFT  (DNODE_BLOCK_SHIFT - DNODE_SHIFT)
 110 #define DNODES_PER_BLOCK        (1ULL << DNODES_PER_BLOCK_SHIFT)
 111 
 112 /*
 113  * This is inaccurate if the indblkshift of the particular object is not the
 114  * max.  But it's only used by userland to calculate the zvol reservation.
 115  */
 116 #define DNODES_PER_LEVEL_SHIFT  (DN_MAX_INDBLKSHIFT - SPA_BLKPTRSHIFT)
 117 #define DNODES_PER_LEVEL        (1ULL << DNODES_PER_LEVEL_SHIFT)
 118 
 119 /* The +2 here is a cheesy way to round up */
 120 #define DN_MAX_LEVELS   (2 + ((DN_MAX_OFFSET_SHIFT - SPA_MINBLOCKSHIFT) / \
 121         (DN_MIN_INDBLKSHIFT - SPA_BLKPTRSHIFT)))
 122 
 123 #define DN_BONUS(dnp)   ((void*)((dnp)->dn_bonus + \
 124         (((dnp)->dn_nblkptr - 1) * sizeof (blkptr_t))))
 125 #define DN_MAX_BONUS_LEN(dnp) \
 126         ((dnp->dn_flags & DNODE_FLAG_SPILL_BLKPTR) ? \
 127         (uint8_t *)DN_SPILL_BLKPTR(dnp) - (uint8_t *)DN_BONUS(dnp) : \
 128         (uint8_t *)(dnp + (dnp->dn_extra_slots + 1)) - (uint8_t *)DN_BONUS(dnp))
 129 
 130 #define DN_USED_BYTES(dnp) (((dnp)->dn_flags & DNODE_FLAG_USED_BYTES) ? \
 131         (dnp)->dn_used : (dnp)->dn_used << SPA_MINBLOCKSHIFT)
 132 
 133 #define EPB(blkshift, typeshift)        (1 << (blkshift - typeshift))
 134 
 135 struct dmu_buf_impl;
 136 struct objset;
 137 struct zio;
 138 
 139 enum dnode_dirtycontext {
 140         DN_UNDIRTIED,
 141         DN_DIRTY_OPEN,
 142         DN_DIRTY_SYNC
 143 };
 144 
 145 /* Is dn_used in bytes?  if not, it's in multiples of SPA_MINBLOCKSIZE */
 146 #define DNODE_FLAG_USED_BYTES                   (1 << 0)
 147 #define DNODE_FLAG_USERUSED_ACCOUNTED           (1 << 1)
 148 
 149 /* Does dnode have a SA spill blkptr in bonus? */
 150 #define DNODE_FLAG_SPILL_BLKPTR                 (1 << 2)
 151 
 152 /* User/Group/Project dnode accounting */
 153 #define DNODE_FLAG_USEROBJUSED_ACCOUNTED        (1 << 3)
 154 
 155 /*
 156  * VARIABLE-LENGTH (LARGE) DNODES
 157  *
 158  * The motivation for variable-length dnodes is to eliminate the overhead
 159  * associated with using spill blocks.  Spill blocks are used to store
 160  * system attribute data (i.e. file metadata) that does not fit in the
 161  * dnode's bonus buffer. By allowing a larger bonus buffer area the use of
 162  * a spill block can be avoided.  Spill blocks potentially incur an
 163  * additional read I/O for every dnode in a dnode block. As a worst case
 164  * example, reading 32 dnodes from a 16k dnode block and all of the spill
 165  * blocks could issue 33 separate reads. Now suppose those dnodes have size
 166  * 1024 and therefore don't need spill blocks. Then the worst case number
 167  * of blocks read is reduced to from 33 to two--one per dnode block.
 168  *
 169  * ZFS-on-Linux systems that make heavy use of extended attributes benefit
 170  * from this feature. In particular, ZFS-on-Linux supports the xattr=sa
 171  * dataset property which allows file extended attribute data to be stored
 172  * in the dnode bonus buffer as an alternative to the traditional
 173  * directory-based format. Workloads such as SELinux and the Lustre
 174  * distributed filesystem often store enough xattr data to force spill
 175  * blocks when xattr=sa is in effect. Large dnodes may therefore provide a
 176  * performance benefit to such systems. Other use cases that benefit from
 177  * this feature include files with large ACLs and symbolic links with long
 178  * target names.
 179  *
 180  * The size of a dnode may be a multiple of 512 bytes up to the size of a
 181  * dnode block (currently 16384 bytes). The dn_extra_slots field of the
 182  * on-disk dnode_phys_t structure describes the size of the physical dnode
 183  * on disk. The field represents how many "extra" dnode_phys_t slots a
 184  * dnode consumes in its dnode block. This convention results in a value of
 185  * 0 for 512 byte dnodes which preserves on-disk format compatibility with
 186  * older software which doesn't support large dnodes.
 187  *
 188  * Similarly, the in-memory dnode_t structure has a dn_num_slots field
 189  * to represent the total number of dnode_phys_t slots consumed on disk.
 190  * Thus dn->dn_num_slots is 1 greater than the corresponding
 191  * dnp->dn_extra_slots. This difference in convention was adopted
 192  * because, unlike on-disk structures, backward compatibility is not a
 193  * concern for in-memory objects, so we used a more natural way to
 194  * represent size for a dnode_t.
 195  *
 196  * The default size for newly created dnodes is determined by the value of
 197  * the "dnodesize" dataset property. By default the property is set to
 198  * "legacy" which is compatible with older software. Setting the property
 199  * to "auto" will allow the filesystem to choose the most suitable dnode
 200  * size. Currently this just sets the default dnode size to 1k, but future
 201  * code improvements could dynamically choose a size based on observed
 202  * workload patterns. Dnodes of varying sizes can coexist within the same
 203  * dataset and even within the same dnode block.
 204  */
 205 
 206 #define DNODE_CRYPT_PORTABLE_FLAGS_MASK         (DNODE_FLAG_SPILL_BLKPTR)
 207 
 208 typedef struct dnode_phys {
 209         uint8_t dn_type;                /* dmu_object_type_t */
 210         uint8_t dn_indblkshift;         /* ln2(indirect block size) */
 211         uint8_t dn_nlevels;             /* 1=dn_blkptr->data blocks */
 212         uint8_t dn_nblkptr;             /* length of dn_blkptr */
 213         uint8_t dn_bonustype;           /* type of data in bonus buffer */
 214         uint8_t dn_checksum;            /* ZIO_CHECKSUM type */
 215         uint8_t dn_compress;            /* ZIO_COMPRESS type */
 216         uint8_t dn_flags;               /* DNODE_FLAG_* */
 217         uint16_t dn_datablkszsec;       /* data block size in 512b sectors */
 218         uint16_t dn_bonuslen;           /* length of dn_bonus */
 219         uint8_t dn_extra_slots;         /* # of subsequent slots consumed */
 220         uint8_t dn_pad2[3];
 221 
 222         /* accounting is protected by dn_dirty_mtx */
 223         uint64_t dn_maxblkid;           /* largest allocated block ID */
 224         uint64_t dn_used;               /* bytes (or sectors) of disk space */
 225 
 226         /*
 227          * Both dn_pad2 and dn_pad3 are protected by the block's MAC. This
 228          * allows us to protect any fields that might be added here in the
 229          * future. In either case, developers will want to check
 230          * zio_crypt_init_uios_dnode() to ensure the new field is being
 231          * protected properly.
 232          */
 233         uint64_t dn_pad3[4];
 234         union {
 235                 blkptr_t dn_blkptr[1+DN_OLD_MAX_BONUSLEN/sizeof (blkptr_t)];
 236                 struct {
 237                         blkptr_t __dn_ignore1;
 238                         uint8_t dn_bonus[DN_OLD_MAX_BONUSLEN];
 239                 };
 240                 struct {
 241                         blkptr_t __dn_ignore2;
 242                         uint8_t __dn_ignore3[DN_OLD_MAX_BONUSLEN -
 243                             sizeof (blkptr_t)];
 244                         blkptr_t dn_spill;
 245                 };
 246         };
 247 } dnode_phys_t;
 248 
 249 #define DN_SPILL_BLKPTR(dnp)    ((blkptr_t *)((char *)(dnp) +           \
 250         (((dnp)->dn_extra_slots + 1) << DNODE_SHIFT) - (1 << SPA_BLKPTRSHIFT)))
 251 
 252 struct dnode {
 253         /*
 254          * Protects the structure of the dnode, including the number of levels
 255          * of indirection (dn_nlevels), dn_maxblkid, and dn_next_*
 256          */
 257         krwlock_t dn_struct_rwlock;
 258 
 259         /* Our link on dn_objset->os_dnodes list; protected by os_lock.  */
 260         list_node_t dn_link;
 261 
 262         /* immutable: */
 263         struct objset *dn_objset;
 264         uint64_t dn_object;
 265         struct dmu_buf_impl *dn_dbuf;
 266         struct dnode_handle *dn_handle;
 267         dnode_phys_t *dn_phys; /* pointer into dn->dn_dbuf->db.db_data */
 268 
 269         /*
 270          * Copies of stuff in dn_phys.  They're valid in the open
 271          * context (eg. even before the dnode is first synced).
 272          * Where necessary, these are protected by dn_struct_rwlock.
 273          */
 274         dmu_object_type_t dn_type;      /* object type */
 275         uint16_t dn_bonuslen;           /* bonus length */
 276         uint8_t dn_bonustype;           /* bonus type */
 277         uint8_t dn_nblkptr;             /* number of blkptrs (immutable) */
 278         uint8_t dn_checksum;            /* ZIO_CHECKSUM type */
 279         uint8_t dn_compress;            /* ZIO_COMPRESS type */
 280         uint8_t dn_nlevels;
 281         uint8_t dn_indblkshift;
 282         uint8_t dn_datablkshift;        /* zero if blksz not power of 2! */
 283         uint8_t dn_moved;               /* Has this dnode been moved? */
 284         uint16_t dn_datablkszsec;       /* in 512b sectors */
 285         uint32_t dn_datablksz;          /* in bytes */
 286         uint64_t dn_maxblkid;
 287         uint8_t dn_next_type[TXG_SIZE];
 288         uint8_t dn_num_slots;           /* metadnode slots consumed on disk */
 289         uint8_t dn_next_nblkptr[TXG_SIZE];
 290         uint8_t dn_next_nlevels[TXG_SIZE];
 291         uint8_t dn_next_indblkshift[TXG_SIZE];
 292         uint8_t dn_next_bonustype[TXG_SIZE];
 293         uint8_t dn_rm_spillblk[TXG_SIZE];       /* for removing spill blk */
 294         uint16_t dn_next_bonuslen[TXG_SIZE];
 295         uint32_t dn_next_blksz[TXG_SIZE];       /* next block size in bytes */
 296         uint64_t dn_next_maxblkid[TXG_SIZE];    /* next maxblkid in bytes */
 297 
 298         /* protected by dn_dbufs_mtx; declared here to fill 32-bit hole */
 299         uint32_t dn_dbufs_count;        /* count of dn_dbufs */
 300 
 301         /* protected by os_lock: */
 302         multilist_node_t dn_dirty_link[TXG_SIZE]; /* next on dataset's dirty */
 303 
 304         /* protected by dn_mtx: */
 305         kmutex_t dn_mtx;
 306         list_t dn_dirty_records[TXG_SIZE];
 307         struct range_tree *dn_free_ranges[TXG_SIZE];
 308         uint64_t dn_allocated_txg;
 309         uint64_t dn_free_txg;
 310         uint64_t dn_assigned_txg;
 311         uint64_t dn_dirty_txg;                  /* txg dnode was last dirtied */
 312         kcondvar_t dn_notxholds;
 313         enum dnode_dirtycontext dn_dirtyctx;
 314         uint8_t *dn_dirtyctx_firstset;          /* dbg: contents meaningless */
 315 
 316         /* protected by own devices */
 317         zfs_refcount_t dn_tx_holds;
 318         zfs_refcount_t dn_holds;
 319 
 320         kmutex_t dn_dbufs_mtx;
 321         /*
 322          * Descendent dbufs, ordered by dbuf_compare. Note that dn_dbufs
 323          * can contain multiple dbufs of the same (level, blkid) when a
 324          * dbuf is marked DB_EVICTING without being removed from
 325          * dn_dbufs. To maintain the avl invariant that there cannot be
 326          * duplicate entries, we order the dbufs by an arbitrary value -
 327          * their address in memory. This means that dn_dbufs cannot be used to
 328          * directly look up a dbuf. Instead, callers must use avl_walk, have
 329          * a reference to the dbuf, or look up a non-existant node with
 330          * db_state = DB_SEARCH (see dbuf_free_range for an example).
 331          */
 332         avl_tree_t dn_dbufs;
 333 
 334         /* protected by dn_struct_rwlock */
 335         struct dmu_buf_impl *dn_bonus;  /* bonus buffer dbuf */
 336 
 337         boolean_t dn_have_spill;        /* have spill or are spilling */
 338 
 339         /* parent IO for current sync write */
 340         zio_t *dn_zio;
 341 
 342         /* used in syncing context */
 343         uint64_t dn_oldused;    /* old phys used bytes */
 344         uint64_t dn_oldflags;   /* old phys dn_flags */
 345         uint64_t dn_olduid, dn_oldgid, dn_oldprojid;
 346         uint64_t dn_newuid, dn_newgid, dn_newprojid;
 347         int dn_id_flags;
 348 
 349         /* holds prefetch structure */
 350         struct zfetch   dn_zfetch;
 351 };
 352 
 353 /*
 354  * We use this (otherwise unused) bit to indicate if the value of
 355  * dn_next_maxblkid[txgoff] is valid to use in dnode_sync().
 356  */
 357 #define DMU_NEXT_MAXBLKID_SET           (1ULL << 63)
 358 
 359 /*
 360  * Adds a level of indirection between the dbuf and the dnode to avoid
 361  * iterating descendent dbufs in dnode_move(). Handles are not allocated
 362  * individually, but as an array of child dnodes in dnode_hold_impl().
 363  */
 364 typedef struct dnode_handle {
 365         /* Protects dnh_dnode from modification by dnode_move(). */
 366         zrlock_t dnh_zrlock;
 367         dnode_t *dnh_dnode;
 368 } dnode_handle_t;
 369 
 370 typedef struct dnode_children {
 371         dmu_buf_user_t dnc_dbu;         /* User evict data */
 372         size_t dnc_count;               /* number of children */
 373         dnode_handle_t dnc_children[];  /* sized dynamically */
 374 } dnode_children_t;
 375 
 376 typedef struct free_range {
 377         avl_node_t fr_node;
 378         uint64_t fr_blkid;
 379         uint64_t fr_nblks;
 380 } free_range_t;
 381 
 382 void dnode_special_open(struct objset *dd, dnode_phys_t *dnp,
 383     uint64_t object, dnode_handle_t *dnh);
 384 void dnode_special_close(dnode_handle_t *dnh);
 385 
 386 void dnode_setbonuslen(dnode_t *dn, int newsize, dmu_tx_t *tx);
 387 void dnode_setbonus_type(dnode_t *dn, dmu_object_type_t, dmu_tx_t *tx);
 388 void dnode_rm_spill(dnode_t *dn, dmu_tx_t *tx);
 389 
 390 int dnode_hold(struct objset *dd, uint64_t object,
 391     void *ref, dnode_t **dnp);
 392 int dnode_hold_impl(struct objset *dd, uint64_t object, int flag, int dn_slots,
 393     void *ref, dnode_t **dnp);
 394 boolean_t dnode_add_ref(dnode_t *dn, void *ref);
 395 void dnode_rele(dnode_t *dn, void *ref);
 396 void dnode_rele_and_unlock(dnode_t *dn, void *tag, boolean_t evicting);
 397 int dnode_try_claim(objset_t *os, uint64_t object, int slots);
 398 void dnode_setdirty(dnode_t *dn, dmu_tx_t *tx);
 399 void dnode_sync(dnode_t *dn, dmu_tx_t *tx);
 400 void dnode_allocate(dnode_t *dn, dmu_object_type_t ot, int blocksize, int ibs,
 401     dmu_object_type_t bonustype, int bonuslen, int dn_slots, dmu_tx_t *tx);
 402 void dnode_reallocate(dnode_t *dn, dmu_object_type_t ot, int blocksize,
 403     dmu_object_type_t bonustype, int bonuslen, int dn_slots,
 404     boolean_t keep_spill, dmu_tx_t *tx);
 405 void dnode_free(dnode_t *dn, dmu_tx_t *tx);
 406 void dnode_byteswap(dnode_phys_t *dnp);
 407 void dnode_buf_byteswap(void *buf, size_t size);
 408 void dnode_verify(dnode_t *dn);
 409 int dnode_set_nlevels(dnode_t *dn, int nlevels, dmu_tx_t *tx);
 410 int dnode_set_blksz(dnode_t *dn, uint64_t size, int ibs, dmu_tx_t *tx);
 411 void dnode_free_range(dnode_t *dn, uint64_t off, uint64_t len, dmu_tx_t *tx);
 412 void dnode_diduse_space(dnode_t *dn, int64_t space);
 413 void dnode_new_blkid(dnode_t *dn, uint64_t blkid, dmu_tx_t *tx,
 414     boolean_t have_read, boolean_t force);
 415 uint64_t dnode_block_freed(dnode_t *dn, uint64_t blkid);
 416 void dnode_init(void);
 417 void dnode_fini(void);
 418 int dnode_next_offset(dnode_t *dn, int flags, uint64_t *off,
 419     int minlvl, uint64_t blkfill, uint64_t txg);
 420 void dnode_evict_dbufs(dnode_t *dn);
 421 void dnode_evict_bonus(dnode_t *dn);
 422 void dnode_free_interior_slots(dnode_t *dn);
 423 boolean_t dnode_needs_remap(const dnode_t *dn);
 424 
 425 #define DNODE_IS_DIRTY(_dn)                                             \
 426         ((_dn)->dn_dirty_txg >= spa_syncing_txg((_dn)->dn_objset->os_spa))
 427 
 428 #define DNODE_IS_CACHEABLE(_dn)                                         \
 429         ((_dn)->dn_objset->os_primary_cache == ZFS_CACHE_ALL ||           \
 430         (DMU_OT_IS_METADATA((_dn)->dn_type) &&                               \
 431         (_dn)->dn_objset->os_primary_cache == ZFS_CACHE_METADATA))
 432 
 433 #define DNODE_META_IS_CACHEABLE(_dn)                                    \
 434         ((_dn)->dn_objset->os_primary_cache == ZFS_CACHE_ALL ||           \
 435         (_dn)->dn_objset->os_primary_cache == ZFS_CACHE_METADATA)
 436 
 437 /*
 438  * Used for dnodestats kstat.
 439  */
 440 typedef struct dnode_stats {
 441         /*
 442          * Number of failed attempts to hold a meta dnode dbuf.
 443          */
 444         kstat_named_t dnode_hold_dbuf_hold;
 445         /*
 446          * Number of failed attempts to read a meta dnode dbuf.
 447          */
 448         kstat_named_t dnode_hold_dbuf_read;
 449         /*
 450          * Number of times dnode_hold(..., DNODE_MUST_BE_ALLOCATED) was able
 451          * to hold the requested object number which was allocated.  This is
 452          * the common case when looking up any allocated object number.
 453          */
 454         kstat_named_t dnode_hold_alloc_hits;
 455         /*
 456          * Number of times dnode_hold(..., DNODE_MUST_BE_ALLOCATED) was not
 457          * able to hold the request object number because it was not allocated.
 458          */
 459         kstat_named_t dnode_hold_alloc_misses;
 460         /*
 461          * Number of times dnode_hold(..., DNODE_MUST_BE_ALLOCATED) was not
 462          * able to hold the request object number because the object number
 463          * refers to an interior large dnode slot.
 464          */
 465         kstat_named_t dnode_hold_alloc_interior;
 466         /*
 467          * Number of times dnode_hold(..., DNODE_MUST_BE_ALLOCATED) needed
 468          * to retry acquiring slot zrl locks due to contention.
 469          */
 470         kstat_named_t dnode_hold_alloc_lock_retry;
 471         /*
 472          * Number of times dnode_hold(..., DNODE_MUST_BE_ALLOCATED) did not
 473          * need to create the dnode because another thread did so after
 474          * dropping the read lock but before acquiring the write lock.
 475          */
 476         kstat_named_t dnode_hold_alloc_lock_misses;
 477         /*
 478          * Number of times dnode_hold(..., DNODE_MUST_BE_ALLOCATED) found
 479          * a free dnode instantiated by dnode_create() but not yet allocated
 480          * by dnode_allocate().
 481          */
 482         kstat_named_t dnode_hold_alloc_type_none;
 483         /*
 484          * Number of times dnode_hold(..., DNODE_MUST_BE_FREE) was able
 485          * to hold the requested range of free dnode slots.
 486          */
 487         kstat_named_t dnode_hold_free_hits;
 488         /*
 489          * Number of times dnode_hold(..., DNODE_MUST_BE_FREE) was not
 490          * able to hold the requested range of free dnode slots because
 491          * at least one slot was allocated.
 492          */
 493         kstat_named_t dnode_hold_free_misses;
 494         /*
 495          * Number of times dnode_hold(..., DNODE_MUST_BE_FREE) was not
 496          * able to hold the requested range of free dnode slots because
 497          * after acquiring the zrl lock at least one slot was allocated.
 498          */
 499         kstat_named_t dnode_hold_free_lock_misses;
 500         /*
 501          * Number of times dnode_hold(..., DNODE_MUST_BE_FREE) needed
 502          * to retry acquiring slot zrl locks due to contention.
 503          */
 504         kstat_named_t dnode_hold_free_lock_retry;
 505         /*
 506          * Number of times dnode_hold(..., DNODE_MUST_BE_FREE) requested
 507          * a range of dnode slots which were held by another thread.
 508          */
 509         kstat_named_t dnode_hold_free_refcount;
 510         /*
 511          * Number of times dnode_hold(..., DNODE_MUST_BE_FREE) requested
 512          * a range of dnode slots which would overflow the dnode_phys_t.
 513          */
 514         kstat_named_t dnode_hold_free_overflow;
 515         /*
 516          * Number of times dnode_free_interior_slots() needed to retry
 517          * acquiring a slot zrl lock due to contention.
 518          */
 519         kstat_named_t dnode_free_interior_lock_retry;
 520         /*
 521          * Number of new dnodes allocated by dnode_allocate().
 522          */
 523         kstat_named_t dnode_allocate;
 524         /*
 525          * Number of dnodes re-allocated by dnode_reallocate().
 526          */
 527         kstat_named_t dnode_reallocate;
 528         /*
 529          * Number of meta dnode dbufs evicted.
 530          */
 531         kstat_named_t dnode_buf_evict;
 532         /*
 533          * Number of times dmu_object_alloc*() reached the end of the existing
 534          * object ID chunk and advanced to a new one.
 535          */
 536         kstat_named_t dnode_alloc_next_chunk;
 537         /*
 538          * Number of times multiple threads attempted to allocate a dnode
 539          * from the same block of free dnodes.
 540          */
 541         kstat_named_t dnode_alloc_race;
 542         /*
 543          * Number of times dmu_object_alloc*() was forced to advance to the
 544          * next meta dnode dbuf due to an error from  dmu_object_next().
 545          */
 546         kstat_named_t dnode_alloc_next_block;
 547         /*
 548          * Statistics for tracking dnodes which have been moved.
 549          */
 550         kstat_named_t dnode_move_invalid;
 551         kstat_named_t dnode_move_recheck1;
 552         kstat_named_t dnode_move_recheck2;
 553         kstat_named_t dnode_move_special;
 554         kstat_named_t dnode_move_handle;
 555         kstat_named_t dnode_move_rwlock;
 556         kstat_named_t dnode_move_active;
 557 } dnode_stats_t;
 558 
 559 extern dnode_stats_t dnode_stats;
 560 
 561 #define DNODE_STAT_INCR(stat, val) \
 562     atomic_add_64(&dnode_stats.stat.value.ui64, (val));
 563 #define DNODE_STAT_BUMP(stat) \
 564     DNODE_STAT_INCR(stat, 1);
 565 
 566 #ifdef ZFS_DEBUG
 567 
 568 /*
 569  * There should be a ## between the string literal and fmt, to make it
 570  * clear that we're joining two strings together, but that piece of shit
 571  * gcc doesn't support that preprocessor token.
 572  */
 573 #define dprintf_dnode(dn, fmt, ...) do { \
 574         if (zfs_flags & ZFS_DEBUG_DPRINTF) { \
 575         char __db_buf[32]; \
 576         uint64_t __db_obj = (dn)->dn_object; \
 577         if (__db_obj == DMU_META_DNODE_OBJECT) \
 578                 (void) strcpy(__db_buf, "mdn"); \
 579         else \
 580                 (void) snprintf(__db_buf, sizeof (__db_buf), "%lld", \
 581                     (u_longlong_t)__db_obj);\
 582         dprintf_ds((dn)->dn_objset->os_dsl_dataset, "obj=%s " fmt, \
 583             __db_buf, __VA_ARGS__); \
 584         } \
 585 _NOTE(CONSTCOND) } while (0)
 586 
 587 #define DNODE_VERIFY(dn)                dnode_verify(dn)
 588 #define FREE_VERIFY(db, start, end, tx) free_verify(db, start, end, tx)
 589 
 590 #else
 591 
 592 #define dprintf_dnode(db, fmt, ...)
 593 #define DNODE_VERIFY(dn)
 594 #define FREE_VERIFY(db, start, end, tx)
 595 
 596 #endif
 597 
 598 #ifdef  __cplusplus
 599 }
 600 #endif
 601 
 602 #endif  /* _SYS_DNODE_H */