sys/vfs/hammer/hammer_freemap.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_freemap.c,v 1.8 2008/05/03 05:28:55 dillon Exp $
  35  */
  36
  37 /*
  38  * HAMMER freemap - bigblock allocator.  The freemap is a 2-layer blockmap
  39  * with one layer2 entry for each big-block in the filesystem.  Big blocks
  40  * are 8MB blocks.
  41  *
  42  * Our allocator is fairly straightforward, we just iterate through available
  43  * blocks looking for a free one.  We shortcut the iteration based on
  44  * layer1 availability.
  45  */
  46
  47 #include "hammer.h"
  48
  49 hammer_off_t
  50 hammer_freemap_alloc(hammer_transaction_t trans, hammer_off_t owner,
  51                      int *errorp)
  52 {
  53         hammer_volume_ondisk_t ondisk;
  54         hammer_off_t layer1_offset;
  55         hammer_off_t layer2_offset;
  56         hammer_off_t result_offset;
  57         hammer_blockmap_t blockmap;
  58         hammer_buffer_t buffer1 = NULL;
  59         hammer_buffer_t buffer2 = NULL;
  60         struct hammer_blockmap_layer1 *layer1;
  61         struct hammer_blockmap_layer2 *layer2;
  62         int vol_no;
  63         int loops = 0;
  64
  65         *errorp = 0;
  66         ondisk = trans->rootvol->ondisk;
  67
  68         blockmap = &trans->hmp->blockmap[HAMMER_ZONE_FREEMAP_INDEX];
  69         result_offset = blockmap->next_offset;
  70         vol_no = HAMMER_VOL_DECODE(result_offset);
  71         for (;;) {
  72                 layer1_offset = blockmap->phys_offset +
  73                                 HAMMER_BLOCKMAP_LAYER1_OFFSET(result_offset);
  74
  75                 layer1 = hammer_bread(trans->hmp, layer1_offset, errorp, &buffer1);
  76                 if (layer1->phys_offset == HAMMER_BLOCKMAP_UNAVAIL) {
  77                         /*
  78                          * End-of-volume, try next volume.
  79                          */
  80 new_volume:
  81                         ++vol_no;
  82                         if (vol_no >= trans->hmp->nvolumes)
  83                                 vol_no = 0;
  84                         result_offset = HAMMER_ENCODE_RAW_BUFFER(vol_no, 0);
  85                         if (vol_no == 0 && ++loops == 2) {
  86                                 *errorp = ENOSPC;
  87                                 result_offset = 0;
  88                                 goto done;
  89                         }
  90                 } else {
  91                         layer2_offset = layer1->phys_offset +
  92                                 HAMMER_BLOCKMAP_LAYER2_OFFSET(result_offset);
  93                         layer2 = hammer_bread(trans->hmp, layer2_offset, errorp,
  94                                               &buffer2);
  95                         if (layer2->u.owner == HAMMER_BLOCKMAP_FREE) {
  96                                 hammer_modify_buffer(trans, buffer2,
  97                                                      layer2, sizeof(*layer2));
  98                                 layer2->u.owner = owner &
  99                                                 ~HAMMER_LARGEBLOCK_MASK64;
 100                                 hammer_modify_buffer_done(buffer2);
 101                                 hammer_modify_buffer(trans, buffer1,
 102                                                      layer1, sizeof(*layer1));
 103                                 --layer1->blocks_free;
 104                                 hammer_modify_buffer_done(buffer1);
 105                                 hammer_modify_volume(trans, trans->rootvol,
 106                                      &ondisk->vol0_stat_freebigblocks,
 107                                      sizeof(ondisk->vol0_stat_freebigblocks));
 108                                 --ondisk->vol0_stat_freebigblocks;
 109                                 hammer_modify_volume_done(trans->rootvol);
 110                                 break;
 111                         }
 112                         if (layer1->blocks_free == 0 ||
 113                             layer2->u.owner == HAMMER_BLOCKMAP_UNAVAIL) {
 114                                 /*
 115                                  * layer2 has no free blocks remaining,
 116                                  * skip to the next layer.
 117                                  */
 118                                 result_offset = (result_offset + HAMMER_BLOCKMAP_LAYER2_MASK) & ~HAMMER_BLOCKMAP_LAYER2_MASK;
 119                                 if (HAMMER_VOL_DECODE(result_offset) != vol_no)
 120                                         goto new_volume;
 121                         } else {
 122                                 result_offset += HAMMER_LARGEBLOCK_SIZE;
 123                                 if (HAMMER_VOL_DECODE(result_offset) != vol_no)
 124                                         goto new_volume;
 125                         }
 126                 }
 127         }
 128         hammer_modify_volume(trans, trans->rootvol, NULL, 0);
 129         blockmap->next_offset = result_offset + HAMMER_LARGEBLOCK_SIZE;
 130         hammer_modify_volume_done(trans->rootvol);
 131 done:
 132         if (buffer1)
 133                 hammer_rel_buffer(buffer1, 0);
 134         if (buffer2)
 135                 hammer_rel_buffer(buffer2, 0);
 136         return(result_offset);
 137 }
 138
 139 void
 140 hammer_freemap_free(hammer_transaction_t trans, hammer_off_t phys_offset,
 141                     hammer_off_t owner, int *errorp)
 142 {
 143         hammer_volume_ondisk_t ondisk;
 144         hammer_off_t layer1_offset;
 145         hammer_off_t layer2_offset;
 146         hammer_blockmap_t blockmap;
 147         hammer_buffer_t buffer1 = NULL;
 148         hammer_buffer_t buffer2 = NULL;
 149         struct hammer_blockmap_layer1 *layer1;
 150         struct hammer_blockmap_layer2 *layer2;
 151
 152         KKASSERT((phys_offset & HAMMER_LARGEBLOCK_MASK64) == 0);
 153
 154         hammer_uncache_buffer(trans->hmp, phys_offset);
 155         *errorp = 0;
 156         ondisk = trans->rootvol->ondisk;
 157
 158         blockmap = &trans->hmp->blockmap[HAMMER_ZONE_FREEMAP_INDEX];
 159         layer1_offset = blockmap->phys_offset +
 160                         HAMMER_BLOCKMAP_LAYER1_OFFSET(phys_offset);
 161         layer1 = hammer_bread(trans->hmp, layer1_offset, errorp, &buffer1);
 162
 163         KKASSERT(layer1->phys_offset != HAMMER_BLOCKMAP_UNAVAIL);
 164
 165         layer2_offset = layer1->phys_offset +
 166                         HAMMER_BLOCKMAP_LAYER2_OFFSET(phys_offset);
 167         layer2 = hammer_bread(trans->hmp, layer2_offset, errorp, &buffer2);
 168
 169         KKASSERT(layer2->u.owner == (owner & ~HAMMER_LARGEBLOCK_MASK64));
 170         hammer_modify_buffer(trans, buffer1, layer1, sizeof(*layer1));
 171         ++layer1->blocks_free;
 172         hammer_modify_buffer_done(buffer1);
 173         hammer_modify_buffer(trans, buffer2, layer2, sizeof(*layer2));
 174         layer2->u.owner = HAMMER_BLOCKMAP_FREE;
 175         hammer_modify_buffer_done(buffer2);
 176
 177         hammer_modify_volume(trans, trans->rootvol,
 178                              &ondisk->vol0_stat_freebigblocks,
 179                              sizeof(ondisk->vol0_stat_freebigblocks));
 180         ++ondisk->vol0_stat_freebigblocks;
 181         hammer_modify_volume_done(trans->rootvol);
 182
 183         if (buffer1)
 184                 hammer_rel_buffer(buffer1, 0);
 185         if (buffer2)
 186                 hammer_rel_buffer(buffer2, 0);
 187 }
 188