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 1.10 2008/05/04 09:06:45 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         hammer_lock_ex(&trans->hmp->free_lock);
  69
  70         blockmap = &trans->hmp->blockmap[HAMMER_ZONE_FREEMAP_INDEX];
  71         result_offset = blockmap->next_offset;
  72         vol_no = HAMMER_VOL_DECODE(result_offset);
  73         for (;;) {
  74                 layer1_offset = blockmap->phys_offset +
  75                                 HAMMER_BLOCKMAP_LAYER1_OFFSET(result_offset);
  76
  77                 layer1 = hammer_bread(trans->hmp, layer1_offset, errorp, &buffer1);
  78                 if (layer1->phys_offset == HAMMER_BLOCKMAP_UNAVAIL) {
  79                         /*
  80                          * End-of-volume, try next volume.
  81                          */
  82 new_volume:
  83                         ++vol_no;
  84                         if (vol_no >= trans->hmp->nvolumes)
  85                                 vol_no = 0;
  86                         result_offset = HAMMER_ENCODE_RAW_BUFFER(vol_no, 0);
  87                         if (vol_no == 0 && ++loops == 2) {
  88                                 *errorp = ENOSPC;
  89                                 result_offset = 0;
  90                                 goto done;
  91                         }
  92                 } else {
  93                         layer2_offset = layer1->phys_offset +
  94                                 HAMMER_BLOCKMAP_LAYER2_OFFSET(result_offset);
  95                         layer2 = hammer_bread(trans->hmp, layer2_offset, errorp,
  96                                               &buffer2);
  97                         if (layer2->u.owner == HAMMER_BLOCKMAP_FREE) {
  98                                 hammer_modify_buffer(trans, buffer2,
  99                                                      layer2, sizeof(*layer2));
 100                                 layer2->u.owner = owner &
 101                                                 ~HAMMER_LARGEBLOCK_MASK64;
 102                                 hammer_modify_buffer_done(buffer2);
 103                                 hammer_modify_buffer(trans, buffer1,
 104                                                      layer1, sizeof(*layer1));
 105                                 --layer1->blocks_free;
 106                                 hammer_modify_buffer_done(buffer1);
 107                                 hammer_modify_volume_field(trans,
 108                                                      trans->rootvol,
 109                                                      vol0_stat_freebigblocks);
 110                                 --ondisk->vol0_stat_freebigblocks;
 111                                 hammer_modify_volume_done(trans->rootvol);
 112                                 break;
 113                         }
 114                         if (layer1->blocks_free == 0 ||
 115                             layer2->u.owner == HAMMER_BLOCKMAP_UNAVAIL) {
 116                                 /*
 117                                  * layer2 has no free blocks remaining,
 118                                  * skip to the next layer.
 119                                  */
 120                                 result_offset = (result_offset + HAMMER_BLOCKMAP_LAYER2_MASK) & ~HAMMER_BLOCKMAP_LAYER2_MASK;
 121                                 if (HAMMER_VOL_DECODE(result_offset) != vol_no)
 122                                         goto new_volume;
 123                         } else {
 124                                 result_offset += HAMMER_LARGEBLOCK_SIZE;
 125                                 if (HAMMER_VOL_DECODE(result_offset) != vol_no)
 126                                         goto new_volume;
 127                         }
 128                 }
 129         }
 130         hammer_modify_volume(trans, trans->rootvol, NULL, 0);
 131         blockmap->next_offset = result_offset + HAMMER_LARGEBLOCK_SIZE;
 132         hammer_modify_volume_done(trans->rootvol);
 133 done:
 134         hammer_unlock(&trans->hmp->free_lock);
 135         if (buffer1)
 136                 hammer_rel_buffer(buffer1, 0);
 137         if (buffer2)
 138                 hammer_rel_buffer(buffer2, 0);
 139         return(result_offset);
 140 }
 141
 142 void
 143 hammer_freemap_free(hammer_transaction_t trans, hammer_off_t phys_offset,
 144                     hammer_off_t owner, int *errorp)
 145 {
 146         hammer_volume_ondisk_t ondisk;
 147         hammer_off_t layer1_offset;
 148         hammer_off_t layer2_offset;
 149         hammer_blockmap_t blockmap;
 150         hammer_buffer_t buffer1 = NULL;
 151         hammer_buffer_t buffer2 = NULL;
 152         struct hammer_blockmap_layer1 *layer1;
 153         struct hammer_blockmap_layer2 *layer2;
 154
 155         KKASSERT((phys_offset & HAMMER_LARGEBLOCK_MASK64) == 0);
 156
 157         hammer_uncache_buffer(trans->hmp, phys_offset);
 158         *errorp = 0;
 159         ondisk = trans->rootvol->ondisk;
 160
 161         blockmap = &trans->hmp->blockmap[HAMMER_ZONE_FREEMAP_INDEX];
 162         layer1_offset = blockmap->phys_offset +
 163                         HAMMER_BLOCKMAP_LAYER1_OFFSET(phys_offset);
 164         layer1 = hammer_bread(trans->hmp, layer1_offset, errorp, &buffer1);
 165
 166         KKASSERT(layer1->phys_offset != HAMMER_BLOCKMAP_UNAVAIL);
 167
 168         layer2_offset = layer1->phys_offset +
 169                         HAMMER_BLOCKMAP_LAYER2_OFFSET(phys_offset);
 170         layer2 = hammer_bread(trans->hmp, layer2_offset, errorp, &buffer2);
 171
 172         KKASSERT(layer2->u.owner == (owner & ~HAMMER_LARGEBLOCK_MASK64));
 173         hammer_modify_buffer(trans, buffer1, layer1, sizeof(*layer1));
 174         ++layer1->blocks_free;
 175         hammer_modify_buffer_done(buffer1);
 176         hammer_modify_buffer(trans, buffer2, layer2, sizeof(*layer2));
 177         layer2->u.owner = HAMMER_BLOCKMAP_FREE;
 178         hammer_modify_buffer_done(buffer2);
 179
 180         hammer_modify_volume_field(trans, trans->rootvol,
 181                                    vol0_stat_freebigblocks);
 182         ++ondisk->vol0_stat_freebigblocks;
 183         hammer_modify_volume_done(trans->rootvol);
 184
 185         if (buffer1)
 186                 hammer_rel_buffer(buffer1, 0);
 187         if (buffer2)
 188                 hammer_rel_buffer(buffer2, 0);
 189 }
 190