release/src/router/busybox/e2fsprogs/old_e2fsprogs/ext2fs/res_gdt.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * res_gdt.c --- reserve blocks for growing the group descriptor table
   4  *               during online resizing.
   5  *
   6  * Copyright (C) 2002 Andreas Dilger
   7  *
   8  * %Begin-Header%
   9  * This file may be redistributed under the terms of the GNU Public
  10  * License.
  11  * %End-Header%
  12  */
  13
  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         int                     rsv_add;
  69         unsigned long long      apb, inode_size;
  70         blk_t                   dindir_blk, rsv_off, gdt_off, gdt_blk;
  71         int                     dindir_dirty = 0, inode_dirty = 0;
  72
  73         EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
  74
  75         sb = fs->super;
  76
  77         retval = ext2fs_get_mem(2 * fs->blocksize, (void *)&dindir_buf);
  78         if (retval)
  79                 goto out_free;
  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         /* Maximum possible file size (we donly use the dindirect blocks) */
  87         apb = EXT2_ADDR_PER_BLOCK(sb);
  88         rsv_add = fs->blocksize / 512;
  89         if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
  90 #ifdef RES_GDT_DEBUG
  91                 printf("reading GDT dindir %u\n", dindir_blk);
  92 #endif
  93                 retval = ext2fs_read_ind_block(fs, dindir_blk, dindir_buf);
  94                 if (retval)
  95                         goto out_inode;
  96         } else {
  97                 blk_t goal = 3 + sb->s_reserved_gdt_blocks +
  98                         fs->desc_blocks + fs->inode_blocks_per_group;
  99
 100                 retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
 101                 if (retval)
 102                         goto out_free;
 103                 inode.i_mode = LINUX_S_IFREG | 0600;
 104                 inode.i_links_count = 1;
 105                 inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
 106                 inode.i_blocks = rsv_add;
 107                 memset(dindir_buf, 0, fs->blocksize);
 108 #ifdef RES_GDT_DEBUG
 109                 printf("allocated GDT dindir %u\n", dindir_blk);
 110 #endif
 111                 dindir_dirty = inode_dirty = 1;
 112                 inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
 113                 inode_size *= fs->blocksize;
 114                 inode.i_size = inode_size & 0xFFFFFFFF;
 115                 inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF;
 116                 if (inode.i_size_high) {
 117                         sb->s_feature_ro_compat |=
 118                                 EXT2_FEATURE_RO_COMPAT_LARGE_FILE;
 119                 }
 120                 inode.i_ctime = time(NULL);
 121         }
 122
 123         for (rsv_off = 0, gdt_off = fs->desc_blocks,
 124              gdt_blk = sb->s_first_data_block + 1 + fs->desc_blocks;
 125              rsv_off < sb->s_reserved_gdt_blocks;
 126              rsv_off++, gdt_off++, gdt_blk++) {
 127                 unsigned int three = 1, five = 5, seven = 7;
 128                 unsigned int grp, last = 0;
 129                 int gdt_dirty = 0;
 130
 131                 gdt_off %= apb;
 132                 if (!dindir_buf[gdt_off]) {
 133                         /* FIXME XXX XXX
 134                         blk_t new_blk;
 135
 136                         retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
 137                         if (retval)
 138                                 goto out_free;
 139                         if (new_blk != gdt_blk) {
 140                                 // XXX free block
 141                                 retval = -1; // XXX
 142                         }
 143                         */
 144                         gdt_dirty = dindir_dirty = inode_dirty = 1;
 145                         memset(gdt_buf, 0, fs->blocksize);
 146                         dindir_buf[gdt_off] = gdt_blk;
 147                         inode.i_blocks += rsv_add;
 148 #ifdef RES_GDT_DEBUG
 149                         printf("added primary GDT block %u at %u[%u]\n",
 150                                gdt_blk, dindir_blk, gdt_off);
 151 #endif
 152                 } else if (dindir_buf[gdt_off] == gdt_blk) {
 153 #ifdef RES_GDT_DEBUG
 154                         printf("reading primary GDT block %u\n", gdt_blk);
 155 #endif
 156                         retval = ext2fs_read_ind_block(fs, gdt_blk, gdt_buf);
 157                         if (retval)
 158                                 goto out_dindir;
 159                 } else {
 160 #ifdef RES_GDT_DEBUG
 161                         printf("bad primary GDT %u != %u at %u[%u]\n",
 162                                dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
 163 #endif
 164                         retval = EXT2_ET_RESIZE_INODE_CORRUPT;
 165                         goto out_dindir;
 166                 }
 167
 168                 while ((grp = list_backups(fs, &three, &five, &seven)) <
 169                        fs->group_desc_count) {
 170                         blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
 171
 172                         if (!gdt_buf[last]) {
 173 #ifdef RES_GDT_DEBUG
 174                                 printf("added backup GDT %u grp %u@%u[%u]\n",
 175                                        expect, grp, gdt_blk, last);
 176 #endif
 177                                 gdt_buf[last] = expect;
 178                                 inode.i_blocks += rsv_add;
 179                                 gdt_dirty = inode_dirty = 1;
 180                         } else if (gdt_buf[last] != expect) {
 181 #ifdef RES_GDT_DEBUG
 182                                 printf("bad backup GDT %u != %u at %u[%u]\n",
 183                                        gdt_buf[last], expect, gdt_blk, last);
 184 #endif
 185                                 retval = EXT2_ET_RESIZE_INODE_CORRUPT;
 186                                 goto out_dindir;
 187                         }
 188                         last++;
 189                 }
 190                 if (gdt_dirty) {
 191 #ifdef RES_GDT_DEBUG
 192                         printf("writing primary GDT block %u\n", gdt_blk);
 193 #endif
 194                         retval = ext2fs_write_ind_block(fs, gdt_blk, gdt_buf);
 195                         if (retval)
 196                                 goto out_dindir;
 197                 }
 198         }
 199
 200 out_dindir:
 201         if (dindir_dirty) {
 202                 retval2 = ext2fs_write_ind_block(fs, dindir_blk, dindir_buf);
 203                 if (!retval)
 204                         retval = retval2;
 205         }
 206 out_inode:
 207 #ifdef RES_GDT_DEBUG
 208         printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
 209                inode.i_size);
 210 #endif
 211         if (inode_dirty) {
 212                 inode.i_atime = inode.i_mtime = time(NULL);
 213                 retval2 = ext2fs_write_inode(fs, EXT2_RESIZE_INO, &inode);
 214                 if (!retval)
 215                         retval = retval2;
 216         }
 217 out_free:
 218         ext2fs_free_mem((void *)&dindir_buf);
 219         return retval;
 220 }