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 "ext2fs.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 filesystem it will be the
  24  * 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  */
  27 static unsigned int list_backups(ext2_filsys fs, unsigned int *three,
  28                                  unsigned int *five, unsigned int *seven)
  29 {
  30         unsigned int *min = three;
  31         int mult = 3;
  32         unsigned int ret;
  33
  34         if (!(fs->super->s_feature_ro_compat &
  35               EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER)) {
  36                 ret = *min;
  37                 *min += 1;
  38                 return ret;
  39         }
  40
  41         if (*five < *min) {
  42                 min = five;
  43                 mult = 5;
  44         }
  45         if (*seven < *min) {
  46                 min = seven;
  47                 mult = 7;
  48         }
  49
  50         ret = *min;
  51         *min *= mult;
  52
  53         return ret;
  54 }
  55
  56 /*
  57  * This code assumes that the reserved blocks have already been marked in-use
  58  * during ext2fs_initialize(), so that they are not allocated for other
  59  * uses before we can add them to the resize inode (which has to come
  60  * after the creation of the inode table).
  61  */
  62 errcode_t ext2fs_create_resize_inode(ext2_filsys fs)
  63 {
  64         errcode_t               retval, retval2;
  65         struct ext2_super_block *sb;
  66         struct ext2_inode       inode;
  67         __u32                   *dindir_buf, *gdt_buf;
  68         unsigned long long      apb, inode_size;
  69         /* FIXME-64 - can't deal with extents */
  70         blk_t                   dindir_blk, rsv_off, gdt_off, gdt_blk;
  71         int                     dindir_dirty = 0, inode_dirty = 0, sb_blk = 0;
  72
  73         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  74
  75         sb = fs->super;
  76
  77         retval = ext2fs_get_array(2, fs->blocksize, &dindir_buf);
  78         if (retval)
  79                 return retval;
  80         gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize);
  81
  82         retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
  83         if (retval)
  84                 goto out_free;
  85
  86         /*
  87          * File systems with a blocksize of 1024 and bigalloc have
  88          * sb->s_first_data_block of 0; yet the superblock is still at
  89          * block #1.  We compensate for it here.
  90          */
  91         sb_blk = sb->s_first_data_block;
  92         if (fs->blocksize == 1024 && sb_blk == 0)
  93                 sb_blk = 1;
  94
  95         /* Maximum possible file size (we donly use the dindirect blocks) */
  96         apb = EXT2_ADDR_PER_BLOCK(sb);
  97         if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
  98 #ifdef RES_GDT_DEBUG
  99                 printf("reading GDT dindir %u\n", dindir_blk);
 100 #endif
 101                 retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
 102                 if (retval)
 103                         goto out_inode;
 104         } else {
 105                 blk_t goal = sb_blk + fs->desc_blocks +
 106                         sb->s_reserved_gdt_blocks + 2 +
 107                         fs->inode_blocks_per_group;
 108
 109                 retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
 110                 if (retval)
 111                         goto out_free;
 112                 inode.i_mode = LINUX_S_IFREG | 0600;
 113                 inode.i_links_count = 1;
 114                 inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
 115                 ext2fs_iblk_set(fs, &inode, 1);
 116                 memset(dindir_buf, 0, fs->blocksize);
 117 #ifdef RES_GDT_DEBUG
 118                 printf("allocated GDT dindir %u\n", dindir_blk);
 119 #endif
 120                 dindir_dirty = inode_dirty = 1;
 121                 inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
 122                 inode_size *= fs->blocksize;
 123                 inode.i_size = inode_size & 0xFFFFFFFF;
 124                 inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF;
 125                 if(inode.i_size_high) {
 126                         sb->s_feature_ro_compat |=
 127                                 EXT2_FEATURE_RO_COMPAT_LARGE_FILE;
 128                 }
 129                 inode.i_ctime = fs->now ? fs->now : time(0);
 130         }
 131
 132         for (rsv_off = 0, gdt_off = fs->desc_blocks,
 133              gdt_blk = sb_blk + 1 + fs->desc_blocks;
 134              rsv_off < sb->s_reserved_gdt_blocks;
 135              rsv_off++, gdt_off++, gdt_blk++) {
 136                 unsigned int three = 1, five = 5, seven = 7;
 137                 unsigned int grp, last = 0;
 138                 int gdt_dirty = 0;
 139
 140                 gdt_off %= apb;
 141                 if (!dindir_buf[gdt_off]) {
 142                         /* FIXME XXX XXX
 143                         blk_t new_blk;
 144
 145                         retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
 146                         if (retval)
 147                                 goto out_free;
 148                         if (new_blk != gdt_blk) {
 149                                 // XXX free block
 150                                 retval = -1; // XXX
 151                         }
 152                         */
 153                         gdt_dirty = dindir_dirty = inode_dirty = 1;
 154                         memset(gdt_buf, 0, fs->blocksize);
 155                         dindir_buf[gdt_off] = gdt_blk;
 156                         ext2fs_iblk_add_blocks(fs, &inode, 1);
 157 #ifdef RES_GDT_DEBUG
 158                         printf("added primary GDT block %u at %u[%u]\n",
 159                                gdt_blk, dindir_blk, gdt_off);
 160 #endif
 161                 } else if (dindir_buf[gdt_off] == gdt_blk) {
 162 #ifdef RES_GDT_DEBUG
 163                         printf("reading primary GDT block %u\n", gdt_blk);
 164 #endif
 165                         retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
 166                         if (retval)
 167                                 goto out_dindir;
 168                 } else {
 169 #ifdef RES_GDT_DEBUG
 170                         printf("bad primary GDT %u != %u at %u[%u]\n",
 171                                dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
 172 #endif
 173                         retval = EXT2_ET_RESIZE_INODE_CORRUPT;
 174                         goto out_dindir;
 175                 }
 176
 177                 while ((grp = list_backups(fs, &three, &five, &seven)) <
 178                        fs->group_desc_count) {
 179                         blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
 180
 181                         if (!gdt_buf[last]) {
 182 #ifdef RES_GDT_DEBUG
 183                                 printf("added backup GDT %u grp %u@%u[%u]\n",
 184                                        expect, grp, gdt_blk, last);
 185 #endif
 186                                 gdt_buf[last] = expect;
 187                                 ext2fs_iblk_add_blocks(fs, &inode, 1);
 188                                 gdt_dirty = inode_dirty = 1;
 189                         } else if (gdt_buf[last] != expect) {
 190 #ifdef RES_GDT_DEBUG
 191                                 printf("bad backup GDT %u != %u at %u[%u]\n",
 192                                        gdt_buf[last], expect, gdt_blk, last);
 193 #endif
 194                                 retval = EXT2_ET_RESIZE_INODE_CORRUPT;
 195                                 goto out_dindir;
 196                         }
 197                         last++;
 198                 }
 199                 if (gdt_dirty) {
 200 #ifdef RES_GDT_DEBUG
 201                         printf("writing primary GDT block %u\n", gdt_blk);
 202 #endif
 203                         retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
 204                         if (retval)
 205                                 goto out_dindir;
 206                 }
 207         }
 208
 209 out_dindir:
 210         if (dindir_dirty) {
 211                 retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
 212                 if (!retval)
 213                         retval = retval2;
 214         }
 215 out_inode:
 216 #ifdef RES_GDT_DEBUG
 217         printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
 218                inode.i_size);
 219 #endif
 220         if (inode_dirty) {
 221                 inode.i_atime = inode.i_mtime = fs->now ? fs->now : time(0);
 222                 retval2 = ext2fs_write_new_inode(fs, EXT2_RESIZE_INO, &inode);
 223                 if (!retval)
 224                         retval = retval2;
 225         }
 226 out_free:
 227         ext2fs_free_mem(&dindir_buf);
 228         return retval;
 229 }
 230