arlad/blocks.c

   1 /*
   2  * Copyright (c) 2005-2006, Stockholms Universitet
   3  * (Stockholm University, Stockholm Sweden)
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the university nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  22  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  25  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  28  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  29  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  30  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  31  * POSSIBILITY OF SUCH DAMAGE.
  32  */
  33
  34 /* $Id$ */
  35
  36 #include <arla_local.h>
  37
  38 /*
  39  * return pointer to block if it is in cache, else NULL
  40  */
  41
  42 struct block *
  43 block_get(FCacheEntry *node, uint64_t offset)
  44 {
  45     struct block *entry = NULL;
  46     Listitem *item;
  47
  48     assert(block_offset(offset) == offset);
  49
  50     for (item = listhead(node->blocks);
  51          item;
  52          item = listnext(node->blocks, item)) {
  53         entry = (struct block *)listdata(item);
  54
  55         if (entry->offset == offset) {
  56             fcache_block_lru(entry);
  57             return entry;
  58         }
  59     }
  60
  61     return NULL;
  62 }
  63
  64 /*
  65  * add a block
  66  *
  67  * Caller needs to link the block into some lru.
  68  */
  69
  70 struct block *
  71 block_add(FCacheEntry *node, uint64_t offset)
  72 {
  73     struct block *new;
  74
  75 #ifdef BLOCKS_PARANOIA
  76     struct block *old = block_get(node, offset);
  77     assert(!old);
  78 #endif
  79
  80     assert(block_offset(offset) == offset);
  81
  82     new = malloc(sizeof(*new));
  83     assert(new);
  84
  85     new->offset = offset;
  86     new->node = node;
  87     new->flags.kernelp = FALSE;
  88     new->flags.busy    = FALSE;
  89
  90     new->lru_le = NULL;
  91     new->block_le = listaddhead(node->blocks, new);
  92
  93     return new;
  94 }
  95
  96 /*
  97  * call callback for every block present in cache
  98  */
  99
 100 void
 101 block_foreach(FCacheEntry *node,
 102               block_callback_t fun,
 103               void *data)
 104 {
 105     struct block *entry;
 106     Listitem *item, *prev;
 107
 108     for (item = listtail(node->blocks);
 109          item;
 110          item = prev) {
 111         prev = listprev(node->blocks, item);
 112         entry = (struct block *)listdata(item);
 113
 114         fun(entry, data);
 115     }
 116 }
 117
 118 /*
 119  * free all block internal resources
 120  *
 121  * Assumes the node is properly locked and that data is taken care of.
 122  */
 123
 124 void
 125 block_free(struct block *block)
 126 {
 127     listdel(block->node->blocks, block->block_le);
 128     free(block);
 129 }
 130
 131 /*
 132  * Return aggregate status for the node.
 133  *
 134  * If we only have busy blocks, return BLOCK_BUSY.   XXX reverse this?
 135  */
 136
 137 BlockState
 138 block_any(FCacheEntry *node)
 139 {
 140     struct block *entry;
 141     Listitem *item, *prev;
 142
 143     if (listemptyp(node->blocks))
 144         return BLOCK_NONE;
 145
 146     for (item = listtail(node->blocks);
 147          item;
 148          item = prev) {
 149         prev = listprev(node->blocks, item);
 150         entry = (struct block *)listdata(item);
 151
 152         if (!entry->flags.busy)
 153             return BLOCK_GOT;
 154     }
 155
 156     return BLOCK_BUSY;
 157 }
 158
 159 /*
 160  * Return TRUE if we have no data.
 161  */
 162
 163 Bool
 164 block_emptyp(FCacheEntry *node)
 165 {
 166     if (listemptyp(node->blocks))
 167         return TRUE;
 168     return FALSE;
 169 }
 170