sys/cddl/contrib/opensolaris/uts/common/fs/zfs/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 2007 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 #pragma ident   "%Z%%M% %I%     %E% SMI"
  30
  31 #include <sys/txg_impl.h>
  32 #include <sys/zio.h>
  33 #include <sys/dnode.h>
  34 #include <sys/zfs_context.h>
  35
  36 #ifdef  __cplusplus
  37 extern "C" {
  38 #endif
  39
  40 /*
  41  * This is the locking strategy for the DMU.  Numbers in parenthesis are
  42  * cases that use that lock order, referenced below:
  43  *
  44  * ARC is self-contained
  45  * bplist is self-contained
  46  * refcount is self-contained
  47  * txg is self-contained (hopefully!)
  48  * zst_lock
  49  * zf_rwlock
  50  *
  51  * XXX try to improve evicting path?
  52  *
  53  * dp_config_rwlock > os_obj_lock > dn_struct_rwlock >
  54  *      dn_dbufs_mtx > hash_mutexes > db_mtx > leafs
  55  *
  56  * dp_config_rwlock
  57  *    must be held before: everything
  58  *    protects dd namespace changes
  59  *    protects property changes globally
  60  *    held from:
  61  *      dsl_dir_open/r:
  62  *      dsl_dir_create_sync/w:
  63  *      dsl_dir_sync_destroy/w:
  64  *      dsl_dir_rename_sync/w:
  65  *      dsl_prop_changed_notify/r:
  66  *
  67  * os_obj_lock
  68  *   must be held before:
  69  *      everything except dp_config_rwlock
  70  *   protects os_obj_next
  71  *   held from:
  72  *      dmu_object_alloc: dn_dbufs_mtx, db_mtx, hash_mutexes, dn_struct_rwlock
  73  *
  74  * dn_struct_rwlock
  75  *   must be held before:
  76  *      everything except dp_config_rwlock and os_obj_lock
  77  *   protects structure of dnode (eg. nlevels)
  78  *      db_blkptr can change when syncing out change to nlevels
  79  *      dn_maxblkid
  80  *      dn_nlevels
  81  *      dn_*blksz*
  82  *      phys nlevels, maxblkid, physical blkptr_t's (?)
  83  *   held from:
  84  *      callers of dbuf_read_impl, dbuf_hold[_impl], dbuf_prefetch
  85  *      dmu_object_info_from_dnode: dn_dirty_mtx (dn_datablksz)
  86  *      dmu_tx_count_free:
  87  *      dbuf_read_impl: db_mtx, dmu_zfetch()
  88  *      dmu_zfetch: zf_rwlock/r, zst_lock, dbuf_prefetch()
  89  *      dbuf_new_size: db_mtx
  90  *      dbuf_dirty: db_mtx
  91  *      dbuf_findbp: (callers, phys? - the real need)
  92  *      dbuf_create: dn_dbufs_mtx, hash_mutexes, db_mtx (phys?)
  93  *      dbuf_prefetch: dn_dirty_mtx, hash_mutexes, db_mtx, dn_dbufs_mtx
  94  *      dbuf_hold_impl: hash_mutexes, db_mtx, dn_dbufs_mtx, dbuf_findbp()
  95  *      dnode_sync/w (increase_indirection): db_mtx (phys)
  96  *      dnode_set_blksz/w: dn_dbufs_mtx (dn_*blksz*)
  97  *      dnode_new_blkid/w: (dn_maxblkid)
  98  *      dnode_free_range/w: dn_dirty_mtx (dn_maxblkid)
  99  *      dnode_next_offset: (phys)
 100  *
 101  * dn_dbufs_mtx
 102  *    must be held before:
 103  *      db_mtx, hash_mutexes
 104  *    protects:
 105  *      dn_dbufs
 106  *      dn_evicted
 107  *    held from:
 108  *      dmu_evict_user: db_mtx (dn_dbufs)
 109  *      dbuf_free_range: db_mtx (dn_dbufs)
 110  *      dbuf_remove_ref: db_mtx, callees:
 111  *              dbuf_hash_remove: hash_mutexes, db_mtx
 112  *      dbuf_create: hash_mutexes, db_mtx (dn_dbufs)
 113  *      dnode_set_blksz: (dn_dbufs)
 114  *
 115  * hash_mutexes (global)
 116  *   must be held before:
 117  *      db_mtx
 118  *   protects dbuf_hash_table (global) and db_hash_next
 119  *   held from:
 120  *      dbuf_find: db_mtx
 121  *      dbuf_hash_insert: db_mtx
 122  *      dbuf_hash_remove: db_mtx
 123  *
 124  * db_mtx (meta-leaf)
 125  *   must be held before:
 126  *      dn_mtx, dn_dirty_mtx, dd_lock (leaf mutexes)
 127  *   protects:
 128  *      db_state
 129  *      db_holds
 130  *      db_buf
 131  *      db_changed
 132  *      db_data_pending
 133  *      db_dirtied
 134  *      db_link
 135  *      db_dirty_node (??)
 136  *      db_dirtycnt
 137  *      db_d.*
 138  *      db.*
 139  *   held from:
 140  *      dbuf_dirty: dn_mtx, dn_dirty_mtx
 141  *      dbuf_dirty->dsl_dir_willuse_space: dd_lock
 142  *      dbuf_dirty->dbuf_new_block->dsl_dataset_block_freeable: dd_lock
 143  *      dbuf_undirty: dn_dirty_mtx (db_d)
 144  *      dbuf_write_done: dn_dirty_mtx (db_state)
 145  *      dbuf_*
 146  *      dmu_buf_update_user: none (db_d)
 147  *      dmu_evict_user: none (db_d) (maybe can eliminate)
 148  *      dbuf_find: none (db_holds)
 149  *      dbuf_hash_insert: none (db_holds)
 150  *      dmu_buf_read_array_impl: none (db_state, db_changed)
 151  *      dmu_sync: none (db_dirty_node, db_d)
 152  *      dnode_reallocate: none (db)
 153  *
 154  * dn_mtx (leaf)
 155  *   protects:
 156  *      dn_dirty_dbufs
 157  *      dn_ranges
 158  *      phys accounting
 159  *      dn_allocated_txg
 160  *      dn_free_txg
 161  *      dn_assigned_txg
 162  *      dd_assigned_tx
 163  *      dn_notxholds
 164  *      dn_dirtyctx
 165  *      dn_dirtyctx_firstset
 166  *      (dn_phys copy fields?)
 167  *      (dn_phys contents?)
 168  *   held from:
 169  *      dnode_*
 170  *      dbuf_dirty: none
 171  *      dbuf_sync: none (phys accounting)
 172  *      dbuf_undirty: none (dn_ranges, dn_dirty_dbufs)
 173  *      dbuf_write_done: none (phys accounting)
 174  *      dmu_object_info_from_dnode: none (accounting)
 175  *      dmu_tx_commit: none
 176  *      dmu_tx_hold_object_impl: none
 177  *      dmu_tx_try_assign: dn_notxholds(cv)
 178  *      dmu_tx_unassign: none
 179  *
 180  * dd_lock (leaf)
 181  *    protects:
 182  *      dd_prop_cbs
 183  *      dd_sync_*
 184  *      dd_used_bytes
 185  *      dd_tempreserved
 186  *      dd_space_towrite
 187  *      dd_myname
 188  *      dd_phys accounting?
 189  *    held from:
 190  *      dsl_dir_*
 191  *      dsl_prop_changed_notify: none (dd_prop_cbs)
 192  *      dsl_prop_register: none (dd_prop_cbs)
 193  *      dsl_prop_unregister: none (dd_prop_cbs)
 194  *      dsl_dataset_block_freeable: none (dd_sync_*)
 195  *
 196  * os_lock (leaf)
 197  *   protects:
 198  *      os_dirty_dnodes
 199  *      os_free_dnodes
 200  *      os_dnodes
 201  *      os_downgraded_dbufs
 202  *      dn_dirtyblksz
 203  *      dn_dirty_link
 204  *   held from:
 205  *      dnode_create: none (os_dnodes)
 206  *      dnode_destroy: none (os_dnodes)
 207  *      dnode_setdirty: none (dn_dirtyblksz, os_*_dnodes)
 208  *      dnode_free: none (dn_dirtyblksz, os_*_dnodes)
 209  *
 210  * ds_lock (leaf)
 211  *    protects:
 212  *      ds_user_ptr
 213  *      ds_user_evice_func
 214  *      ds_open_refcount
 215  *      ds_snapname
 216  *      ds_phys accounting
 217  *    held from:
 218  *      dsl_dataset_*
 219  *
 220  * dr_mtx (leaf)
 221  *    protects:
 222  *      dr_children
 223  *    held from:
 224  *      dbuf_dirty
 225  *      dbuf_undirty
 226  *      dbuf_sync_indirect
 227  *      dnode_new_blkid
 228  */
 229
 230 struct objset;
 231 struct dmu_pool;
 232
 233 #ifdef  __cplusplus
 234 }
 235 #endif
 236
 237 #endif  /* _SYS_DMU_IMPL_H */