sys/vfs/hammer/hammer_mirror.c

   1 /*
   2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/vfs/hammer/hammer_mirror.c,v 1.1 2008/06/24 17:38:17 dillon Exp $
  35  */
  36 /*
  37  * HAMMER mirroring ioctls - serialize and deserialize modifications made
  38  *                           to a filesystem.
  39  */
  40
  41 #include "hammer.h"
  42
  43 int
  44 hammer_ioc_mirror_read(hammer_transaction_t trans, hammer_inode_t ip,
  45                        struct hammer_ioc_mirror_rw *mirror)
  46 {
  47         struct hammer_cursor cursor;
  48         hammer_btree_elm_t elm;
  49         int error;
  50
  51         if ((mirror->key_beg.localization | mirror->key_end.localization) &
  52             HAMMER_LOCALIZE_PSEUDOFS_MASK) {
  53                 return(EINVAL);
  54         }
  55         if (hammer_btree_cmp(&mirror->key_beg, &mirror->key_end) > 0)
  56                 return(EINVAL);
  57
  58         mirror->key_cur = mirror->key_beg;
  59         mirror->key_cur.localization += ip->obj_localization;
  60
  61 retry:
  62         error = hammer_init_cursor(trans, &cursor, NULL, NULL);
  63         if (error) {
  64                 hammer_done_cursor(&cursor);
  65                 goto failed;
  66         }
  67         cursor.key_beg = mirror->key_cur;
  68         cursor.key_end = mirror->key_end;
  69         cursor.key_end.localization += ip->obj_localization;
  70
  71         cursor.flags |= HAMMER_CURSOR_END_INCLUSIVE;
  72         cursor.flags |= HAMMER_CURSOR_BACKEND;
  73
  74         /*
  75          * This flag allows the btree scan code to return internal nodes
  76          * at every index, giving the mirroring code the ability to skip
  77          * whole sub-trees based on mirror_tid.
  78          */
  79         cursor.flags |= HAMMER_CURSOR_MIRRORING;
  80
  81         error = hammer_btree_first(&cursor);
  82         while (error == 0) {
  83                 /*
  84                  * Internal or Leaf node
  85                  */
  86                 elm = &cursor.node->ondisk->elms[cursor.index];
  87                 reblock->key_cur.obj_id = elm->base.obj_id;
  88                 reblock->key_cur.localization = elm->base.localization;
  89
  90                 /*
  91                  * Yield to more important tasks
  92                  */
  93                 if ((error = hammer_signal_check(trans->hmp)) != 0)
  94                         break;
  95                 if (trans->hmp->sync_lock.wanted) {
  96                         tsleep(trans, 0, "hmrslo", hz / 10);
  97                 }
  98                 if (trans->hmp->locked_dirty_count +
  99                     trans->hmp->io_running_count > hammer_limit_dirtybufs) {
 100                         hammer_flusher_async(trans->hmp);
 101                         tsleep(trans, 0, "hmrslo", hz / 10);
 102                 }
 103
 104 #if 0
 105                 /*
 106                  * Acquiring the sync_lock prevents the operation from
 107                  * crossing a synchronization boundary.
 108                  *
 109                  * NOTE: cursor.node may have changed on return.
 110                  */
 111                 hammer_sync_lock_sh(trans);
 112                 error = hammer_reblock_helper(reblock, &cursor, elm);
 113                 hammer_sync_unlock(trans);
 114 #endif
 115                 if (error == 0) {
 116                         cursor.flags |= HAMMER_CURSOR_ATEDISK;
 117                         error = hammer_btree_iterate(&cursor);
 118                 }
 119         }
 120         if (error == ENOENT)
 121                 error = 0;
 122         hammer_done_cursor(&cursor);
 123         if (error == EDEADLK)
 124                 goto retry;
 125         if (error == EINTR) {
 126                 reblock->head.flags |= HAMMER_IOC_HEAD_INTR;
 127                 error = 0;
 128         }
 129 failed:
 130         mirror->key_cur.localization &= HAMMER_LOCALIZE_MASK;
 131         return(error);
 132 }
 133