lib/ext2fs/res_gdt.c

   1 /*
   2  * res_gdt.c --- reserve blocks for growing the group descriptor table
   3  *               during online resizing.
   4  *
   5  * Copyright (C) 2002 Andreas Dilger
   6  *
   7  * %Begin-Header%
   8  * This file may be redistributed under the terms of the GNU Library
   9  * General Public License, version 2.
  10  * %End-Header%
  11  */
  12
  13 #include "config.h"
  14 #include <stdio.h>
  15 #include <string.h>
  16 #include <time.h>
  17 #include "ext2_fs.h"
  18 #include "ext2fsP.h"
  19
  20 /*
  21  * Iterate through the groups which hold BACKUP superblock/GDT copies in an
  22  * ext3 filesystem.  The counters should be initialized to 1, 5, and 7 before
  23  * calling this for the first time.  In a sparse_super filesystem it will be
  24  * the sequence of powers of 3, 5, and 7: 1, 3, 5, 7, 9, 25, 27, 49, 81, ...
  25  * For a non-sparse filesystem it will be every group: 1, 2, 3, 4, ...
  26  * For a sparse_super2 filesystem there are two backups in specific groups.
  27  */
  28 dgrp_t ext2fs_list_backups(ext2_filsys fs, dgrp_t *three,
  29                            dgrp_t *five, dgrp_t *seven)
  30 {
  31         dgrp_t *min = three;
  32         unsigned long long mult = 3;
  33         dgrp_t ret;
  34
  35         if (fs && ext2fs_has_feature_sparse_super2(fs->super)) {
  36                 if (*min == 1) {
  37                         *min += 1;
  38                         if (fs->super->s_backup_bgs[0])
  39                                 return fs->super->s_backup_bgs[0];
  40                 }
  41                 if (*min == 2) {
  42                         *min += 1;
  43                         if (fs->super->s_backup_bgs[1])
  44                                 return fs->super->s_backup_bgs[1];
  45                 }
  46
  47                 return fs->group_desc_count;
  48         }
  49
  50         if (fs && !ext2fs_has_feature_sparse_super(fs->super)) {
  51                 ret = *min;
  52                 *min += 1;
  53
  54                 return ret;
  55         }
  56
  57         if (*five < *min) {
  58                 min = five;
  59                 mult = 5;
  60         }
  61         if (*seven < *min) {
  62                 min = seven;
  63                 mult = 7;
  64         }
  65
  66         ret = *min;
  67         mult *= *min;
  68         if (mult > (dgrp_t)-1)
  69                 *min = (dgrp_t)-1;
  70         else
  71                 *min = mult;
  72
  73         return ret;
  74 }
  75
  76 /*
  77  * This code assumes that the reserved blocks have already been marked in-use
  78  * during ext2fs_initialize(), so that they are not allocated for other
  79  * uses before we can add them to the resize inode (which has to come
  80  * after the creation of the inode table).
  81  */
  82 errcode_t ext2fs_create_resize_inode(ext2_filsys fs)
  83 {
  84         errcode_t               retval, retval2;
  85         struct ext2_super_block *sb;
  86         struct ext2_inode       inode;
  87         __u32                   *dindir_buf, *gdt_buf;
  88         unsigned long long      apb, inode_size;
  89         /* FIXME-64 - can't deal with extents */
  90         blk_t                   dindir_blk, rsv_off, gdt_off, gdt_blk;
  91         int                     dindir_dirty = 0, inode_dirty = 0, sb_blk = 0;
  92
  93         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  94
  95         sb = fs->super;
  96
  97         retval = ext2fs_get_array(2, fs->blocksize, &dindir_buf);
  98         if (retval)
  99                 return retval;
 100         gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize);
 101
 102         retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
 103         if (retval)
 104                 goto out_free;
 105
 106         /*
 107          * File systems with a blocksize of 1024 and bigalloc have
 108          * sb->s_first_data_block of 0; yet the superblock is still at
 109          * block #1.  We compensate for it here.
 110          */
 111         sb_blk = sb->s_first_data_block;
 112         if (fs->blocksize == 1024 && sb_blk == 0)
 113                 sb_blk = 1;
 114
 115         /* Maximum possible file size (we only use double indirect blocks) */
 116         apb = EXT2_ADDR_PER_BLOCK(sb);
 117         if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
 118 #ifdef RES_GDT_DEBUG
 119                 printf("reading GDT dindir %u\n", dindir_blk);
 120 #endif
 121                 retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
 122                 if (retval)
 123                         goto out_inode;
 124         } else {
 125                 blk_t goal = sb_blk + fs->desc_blocks +
 126                         sb->s_reserved_gdt_blocks + 2 +
 127                         fs->inode_blocks_per_group;
 128
 129                 retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
 130                 if (retval)
 131                         goto out_free;
 132                 inode.i_mode = LINUX_S_IFREG | 0600;
 133                 inode.i_links_count = 1;
 134                 inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
 135                 ext2fs_iblk_set(fs, &inode, 1);
 136                 memset(dindir_buf, 0, fs->blocksize);
 137 #ifdef RES_GDT_DEBUG
 138                 printf("allocated GDT dindir %u\n", dindir_blk);
 139 #endif
 140                 dindir_dirty = inode_dirty = 1;
 141                 inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
 142                 inode_size *= fs->blocksize;
 143                 retval = ext2fs_inode_size_set(fs, &inode, inode_size);
 144                 if (retval)
 145                         goto out_free;
 146                 inode.i_ctime = ext2fsP_get_time(fs);
 147         }
 148
 149         for (rsv_off = 0, gdt_off = fs->desc_blocks,
 150              gdt_blk = sb_blk + 1 + fs->desc_blocks;
 151              rsv_off < sb->s_reserved_gdt_blocks;
 152              rsv_off++, gdt_off++, gdt_blk++) {
 153                 dgrp_t three = 1, five = 5, seven = 7;
 154                 dgrp_t grp, last = 0;
 155                 int gdt_dirty = 0;
 156
 157                 gdt_off %= apb;
 158                 if (!dindir_buf[gdt_off]) {
 159                         /* FIXME XXX XXX
 160                         blk_t new_blk;
 161
 162                         retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
 163                         if (retval)
 164                                 goto out_free;
 165                         if (new_blk != gdt_blk) {
 166                                 // XXX free block
 167                                 retval = -1; // XXX
 168                         }
 169                         */
 170                         gdt_dirty = dindir_dirty = inode_dirty = 1;
 171                         memset(gdt_buf, 0, fs->blocksize);
 172                         dindir_buf[gdt_off] = gdt_blk;
 173                         ext2fs_iblk_add_blocks(fs, &inode, 1);
 174 #ifdef RES_GDT_DEBUG
 175                         printf("added primary GDT block %u at %u[%u]\n",
 176                                gdt_blk, dindir_blk, gdt_off);
 177 #endif
 178                 } else if (dindir_buf[gdt_off] == gdt_blk) {
 179 #ifdef RES_GDT_DEBUG
 180                         printf("reading primary GDT block %u\n", gdt_blk);
 181 #endif
 182                         retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
 183                         if (retval)
 184                                 goto out_dindir;
 185                 } else {
 186 #ifdef RES_GDT_DEBUG
 187                         printf("bad primary GDT %u != %u at %u[%u]\n",
 188                                dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
 189 #endif
 190                         retval = EXT2_ET_RESIZE_INODE_CORRUPT;
 191                         goto out_dindir;
 192                 }
 193
 194                 while ((grp = ext2fs_list_backups(fs, &three, &five, &seven)) <
 195                        fs->group_desc_count) {
 196                         blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
 197
 198                         if (!gdt_buf[last]) {
 199 #ifdef RES_GDT_DEBUG
 200                                 printf("added backup GDT %u grp %u@%u[%u]\n",
 201                                        expect, grp, gdt_blk, last);
 202 #endif
 203                                 gdt_buf[last] = expect;
 204                                 ext2fs_iblk_add_blocks(fs, &inode, 1);
 205                                 gdt_dirty = inode_dirty = 1;
 206                         } else if (gdt_buf[last] != expect) {
 207 #ifdef RES_GDT_DEBUG
 208                                 printf("bad backup GDT %u != %u at %u[%u]\n",
 209                                        gdt_buf[last], expect, gdt_blk, last);
 210 #endif
 211                                 retval = EXT2_ET_RESIZE_INODE_CORRUPT;
 212                                 goto out_dindir;
 213                         }
 214                         last++;
 215                 }
 216                 if (gdt_dirty) {
 217 #ifdef RES_GDT_DEBUG
 218                         printf("writing primary GDT block %u\n", gdt_blk);
 219 #endif
 220                         retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
 221                         if (retval)
 222                                 goto out_dindir;
 223                 }
 224         }
 225
 226 out_dindir:
 227         if (dindir_dirty) {
 228                 retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
 229                 if (!retval)
 230                         retval = retval2;
 231         }
 232 out_inode:
 233 #ifdef RES_GDT_DEBUG
 234         printf("inode.i_blocks = %u, i_size = %lu\n", inode.i_blocks,
 235                EXT2_I_SIZE(&inode));
 236 #endif
 237         if (inode_dirty) {
 238                 time_t now = ext2fsP_get_time(fs);
 239
 240                 ext2fs_inode_xtime_set(&inode, i_atime, now);
 241                 ext2fs_inode_xtime_set(&inode, i_mtime, now);
 242                 retval2 = ext2fs_write_new_inode(fs, EXT2_RESIZE_INO, &inode);
 243                 if (!retval)
 244                         retval = retval2;
 245         }
 246 out_free:
 247         ext2fs_free_mem(&dindir_buf);
 248         return retval;
 249 }
 250