include/sys/dmu_impl.h

   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 2010 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #ifndef _SYS_DMU_IMPL_H
  27 #define _SYS_DMU_IMPL_H
  28
  29 #include <sys/txg_impl.h>
  30 #include <sys/zio.h>
  31 #include <sys/dnode.h>
  32 #include <sys/zfs_context.h>
  33
  34 #ifdef  __cplusplus
  35 extern "C" {
  36 #endif
  37
  38 /*
  39  * This is the locking strategy for the DMU.  Numbers in parenthesis are
  40  * cases that use that lock order, referenced below:
  41  *
  42  * ARC is self-contained
  43  * bplist is self-contained
  44  * refcount is self-contained
  45  * txg is self-contained (hopefully!)
  46  * zst_lock
  47  * zf_rwlock
  48  *
  49  * XXX try to improve evicting path?
  50  *
  51  * dp_config_rwlock > os_obj_lock > dn_struct_rwlock >
  52  *      dn_dbufs_mtx > hash_mutexes > db_mtx > dd_lock > leafs
  53  *
  54  * dp_config_rwlock
  55  *    must be held before: everything
  56  *    protects dd namespace changes
  57  *    protects property changes globally
  58  *    held from:
  59  *      dsl_dir_open/r:
  60  *      dsl_dir_create_sync/w:
  61  *      dsl_dir_sync_destroy/w:
  62  *      dsl_dir_rename_sync/w:
  63  *      dsl_prop_changed_notify/r:
  64  *
  65  * os_obj_lock
  66  *   must be held before:
  67  *      everything except dp_config_rwlock
  68  *   protects os_obj_next
  69  *   held from:
  70  *      dmu_object_alloc: dn_dbufs_mtx, db_mtx, hash_mutexes, dn_struct_rwlock
  71  *
  72  * dn_struct_rwlock
  73  *   must be held before:
  74  *      everything except dp_config_rwlock and os_obj_lock
  75  *   protects structure of dnode (eg. nlevels)
  76  *      db_blkptr can change when syncing out change to nlevels
  77  *      dn_maxblkid
  78  *      dn_nlevels
  79  *      dn_*blksz*
  80  *      phys nlevels, maxblkid, physical blkptr_t's (?)
  81  *   held from:
  82  *      callers of dbuf_read_impl, dbuf_hold[_impl], dbuf_prefetch
  83  *      dmu_object_info_from_dnode: dn_dirty_mtx (dn_datablksz)
  84  *      dmu_tx_count_free:
  85  *      dbuf_read_impl: db_mtx, dmu_zfetch()
  86  *      dmu_zfetch: zf_rwlock/r, zst_lock, dbuf_prefetch()
  87  *      dbuf_new_size: db_mtx
  88  *      dbuf_dirty: db_mtx
  89  *      dbuf_findbp: (callers, phys? - the real need)
  90  *      dbuf_create: dn_dbufs_mtx, hash_mutexes, db_mtx (phys?)
  91  *      dbuf_prefetch: dn_dirty_mtx, hash_mutexes, db_mtx, dn_dbufs_mtx
  92  *      dbuf_hold_impl: hash_mutexes, db_mtx, dn_dbufs_mtx, dbuf_findbp()
  93  *      dnode_sync/w (increase_indirection): db_mtx (phys)
  94  *      dnode_set_blksz/w: dn_dbufs_mtx (dn_*blksz*)
  95  *      dnode_new_blkid/w: (dn_maxblkid)
  96  *      dnode_free_range/w: dn_dirty_mtx (dn_maxblkid)
  97  *      dnode_next_offset: (phys)
  98  *
  99  * dn_dbufs_mtx
 100  *    must be held before:
 101  *      db_mtx, hash_mutexes
 102  *    protects:
 103  *      dn_dbufs
 104  *      dn_evicted
 105  *    held from:
 106  *      dmu_evict_user: db_mtx (dn_dbufs)
 107  *      dbuf_free_range: db_mtx (dn_dbufs)
 108  *      dbuf_remove_ref: db_mtx, callees:
 109  *              dbuf_hash_remove: hash_mutexes, db_mtx
 110  *      dbuf_create: hash_mutexes, db_mtx (dn_dbufs)
 111  *      dnode_set_blksz: (dn_dbufs)
 112  *
 113  * hash_mutexes (global)
 114  *   must be held before:
 115  *      db_mtx
 116  *   protects dbuf_hash_table (global) and db_hash_next
 117  *   held from:
 118  *      dbuf_find: db_mtx
 119  *      dbuf_hash_insert: db_mtx
 120  *      dbuf_hash_remove: db_mtx
 121  *
 122  * db_mtx (meta-leaf)
 123  *   must be held before:
 124  *      dn_mtx, dn_dirty_mtx, dd_lock (leaf mutexes)
 125  *   protects:
 126  *      db_state
 127  *      db_holds
 128  *      db_buf
 129  *      db_changed
 130  *      db_data_pending
 131  *      db_dirtied
 132  *      db_link
 133  *      db_dirty_node (??)
 134  *      db_dirtycnt
 135  *      db_d.*
 136  *      db.*
 137  *   held from:
 138  *      dbuf_dirty: dn_mtx, dn_dirty_mtx
 139  *      dbuf_dirty->dsl_dir_willuse_space: dd_lock
 140  *      dbuf_dirty->dbuf_new_block->dsl_dataset_block_freeable: dd_lock
 141  *      dbuf_undirty: dn_dirty_mtx (db_d)
 142  *      dbuf_write_done: dn_dirty_mtx (db_state)
 143  *      dbuf_*
 144  *      dmu_buf_update_user: none (db_d)
 145  *      dmu_evict_user: none (db_d) (maybe can eliminate)
 146  *      dbuf_find: none (db_holds)
 147  *      dbuf_hash_insert: none (db_holds)
 148  *      dmu_buf_read_array_impl: none (db_state, db_changed)
 149  *      dmu_sync: none (db_dirty_node, db_d)
 150  *      dnode_reallocate: none (db)
 151  *
 152  * dn_mtx (leaf)
 153  *   protects:
 154  *      dn_dirty_dbufs
 155  *      dn_ranges
 156  *      phys accounting
 157  *      dn_allocated_txg
 158  *      dn_free_txg
 159  *      dn_assigned_txg
 160  *      dd_assigned_tx
 161  *      dn_notxholds
 162  *      dn_dirtyctx
 163  *      dn_dirtyctx_firstset
 164  *      (dn_phys copy fields?)
 165  *      (dn_phys contents?)
 166  *   held from:
 167  *      dnode_*
 168  *      dbuf_dirty: none
 169  *      dbuf_sync: none (phys accounting)
 170  *      dbuf_undirty: none (dn_ranges, dn_dirty_dbufs)
 171  *      dbuf_write_done: none (phys accounting)
 172  *      dmu_object_info_from_dnode: none (accounting)
 173  *      dmu_tx_commit: none
 174  *      dmu_tx_hold_object_impl: none
 175  *      dmu_tx_try_assign: dn_notxholds(cv)
 176  *      dmu_tx_unassign: none
 177  *
 178  * dd_lock
 179  *    must be held before:
 180  *      ds_lock
 181  *      ancestors' dd_lock
 182  *    protects:
 183  *      dd_prop_cbs
 184  *      dd_sync_*
 185  *      dd_used_bytes
 186  *      dd_tempreserved
 187  *      dd_space_towrite
 188  *      dd_myname
 189  *      dd_phys accounting?
 190  *    held from:
 191  *      dsl_dir_*
 192  *      dsl_prop_changed_notify: none (dd_prop_cbs)
 193  *      dsl_prop_register: none (dd_prop_cbs)
 194  *      dsl_prop_unregister: none (dd_prop_cbs)
 195  *      dsl_dataset_block_freeable: none (dd_sync_*)
 196  *
 197  * os_lock (leaf)
 198  *   protects:
 199  *      os_dirty_dnodes
 200  *      os_free_dnodes
 201  *      os_dnodes
 202  *      os_downgraded_dbufs
 203  *      dn_dirtyblksz
 204  *      dn_dirty_link
 205  *   held from:
 206  *      dnode_create: none (os_dnodes)
 207  *      dnode_destroy: none (os_dnodes)
 208  *      dnode_setdirty: none (dn_dirtyblksz, os_*_dnodes)
 209  *      dnode_free: none (dn_dirtyblksz, os_*_dnodes)
 210  *
 211  * ds_lock
 212  *    protects:
 213  *      ds_objset
 214  *      ds_open_refcount
 215  *      ds_snapname
 216  *      ds_phys accounting
 217  *      ds_phys userrefs zapobj
 218  *      ds_reserved
 219  *    held from:
 220  *      dsl_dataset_*
 221  *
 222  * dr_mtx (leaf)
 223  *    protects:
 224  *      dr_children
 225  *    held from:
 226  *      dbuf_dirty
 227  *      dbuf_undirty
 228  *      dbuf_sync_indirect
 229  *      dnode_new_blkid
 230  */
 231
 232 struct objset;
 233 struct dmu_pool;
 234
 235 typedef struct dmu_xuio {
 236         int next;
 237         int cnt;
 238         struct arc_buf **bufs;
 239         iovec_t *iovp;
 240 } dmu_xuio_t;
 241
 242 #ifdef  __cplusplus
 243 }
 244 #endif
 245
 246 #endif  /* _SYS_DMU_IMPL_H */