resize/online.c

   1 /*
   2  * online.c --- Do on-line resizing of the ext3 filesystem
   3  *
   4  * Copyright (C) 2006 by Theodore Ts'o
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Public
   8  * License.
   9  * %End-Header%
  10  */
  11
  12 #include "config.h"
  13 #include "resize2fs.h"
  14 #ifdef HAVE_SYS_IOCTL_H
  15 #include <sys/ioctl.h>
  16 #endif
  17 #include <sys/stat.h>
  18 #include <fcntl.h>
  19
  20 extern char *program_name;
  21
  22 #define MAX_32_NUM ((((unsigned long long) 1) << 32) - 1)
  23
  24 errcode_t online_resize_fs(ext2_filsys fs, const char *mtpt,
  25                            blk64_t *new_size, int flags EXT2FS_ATTR((unused)))
  26 {
  27 #ifdef __linux__
  28         struct ext2_new_group_input input;
  29         struct ext4_new_group_input input64;
  30         struct ext2_super_block *sb = fs->super;
  31         unsigned long           new_desc_blocks;
  32         ext2_filsys             new_fs;
  33         errcode_t               retval;
  34         double                  percent;
  35         dgrp_t                  i;
  36         blk_t                   size;
  37         int                     fd, overhead;
  38         int                     use_old_ioctl = 1;
  39
  40         printf(_("Filesystem at %s is mounted on %s; "
  41                  "on-line resizing required\n"), fs->device_name, mtpt);
  42
  43         if (*new_size < ext2fs_blocks_count(sb)) {
  44                 com_err(program_name, 0, _("On-line shrinking not supported"));
  45                 exit(1);
  46         }
  47
  48         /*
  49          * If the number of descriptor blocks is going to increase,
  50          * the on-line resizing inode must be present.
  51          */
  52         new_desc_blocks = ext2fs_div_ceil(
  53                 ext2fs_div64_ceil(*new_size -
  54                                   fs->super->s_first_data_block,
  55                                   EXT2_BLOCKS_PER_GROUP(fs->super)),
  56                 EXT2_DESC_PER_BLOCK(fs->super));
  57         printf("old_desc_blocks = %lu, new_desc_blocks = %lu\n",
  58                fs->desc_blocks, new_desc_blocks);
  59
  60         /*
  61          * Do error checking to make sure the resize will be successful.
  62          */
  63         if ((access("/sys/fs/ext4/features/meta_bg_resize", R_OK) != 0) ||
  64             getenv("RESIZE2FS_NO_META_BG_RESIZE")) {
  65                 if (!EXT2_HAS_COMPAT_FEATURE(fs->super,
  66                                         EXT2_FEATURE_COMPAT_RESIZE_INODE) &&
  67                     (new_desc_blocks != fs->desc_blocks)) {
  68                         com_err(program_name, 0,
  69                                 _("Filesystem does not support online resizing"));
  70                         exit(1);
  71                 }
  72
  73                 if (EXT2_HAS_COMPAT_FEATURE(fs->super,
  74                                         EXT2_FEATURE_COMPAT_RESIZE_INODE) &&
  75                     new_desc_blocks > (fs->desc_blocks +
  76                                        fs->super->s_reserved_gdt_blocks)) {
  77                         com_err(program_name, 0,
  78                                 _("Not enough reserved gdt blocks for resizing"));
  79                         exit(1);
  80                 }
  81
  82                 if ((ext2fs_blocks_count(sb) > MAX_32_NUM) ||
  83                     (*new_size > MAX_32_NUM)) {
  84                         com_err(program_name, 0,
  85                                 _("Kernel does not support resizing a file system this large"));
  86                         exit(1);
  87                 }
  88         }
  89
  90         fd = open(mtpt, O_RDONLY);
  91         if (fd < 0) {
  92                 com_err(program_name, errno,
  93                         _("while trying to open mountpoint %s"), mtpt);
  94                 exit(1);
  95         }
  96
  97         if (ioctl(fd, EXT4_IOC_RESIZE_FS, new_size)) {
  98                 /*
  99                  * If kernel does not support EXT4_IOC_RESIZE_FS, use the
 100                  * old online resize. Note that the old approach does not
 101                  * handle >32 bit file systems
 102                  *
 103                  * Sigh, if we are running a 32-bit binary on a 64-bit
 104                  * kernel (which happens all the time on the MIPS
 105                  * architecture in Debian, but can happen on other CPU
 106                  * architectures as well) we will get EINVAL returned
 107                  * when an ioctl doesn't exist, at least up to Linux
 108                  * 3.1.  See compat_sys_ioctl() in fs/compat_ioctl.c
 109                  * in the kernel sources.  This is probably a kernel
 110                  * bug, but work around it here.
 111                  */
 112                 if ((errno != ENOTTY) && (errno != EINVAL)) {
 113                         if (errno == EPERM)
 114                                 com_err(program_name, 0,
 115                                 _("Permission denied to resize filesystem"));
 116                         else
 117                                 com_err(program_name, errno,
 118                                 _("While checking for on-line resizing "
 119                                   "support"));
 120                         exit(1);
 121                 }
 122         } else {
 123                 close(fd);
 124                 return 0;
 125         }
 126
 127         size = ext2fs_blocks_count(sb);
 128
 129         if (ioctl(fd, EXT2_IOC_GROUP_EXTEND, &size)) {
 130                 if (errno == EPERM)
 131                         com_err(program_name, 0,
 132                                 _("Permission denied to resize filesystem"));
 133                 else if (errno == ENOTTY)
 134                         com_err(program_name, 0,
 135                         _("Kernel does not support online resizing"));
 136                 else
 137                         com_err(program_name, errno,
 138                         _("While checking for on-line resizing support"));
 139                 exit(1);
 140         }
 141
 142         percent = (ext2fs_r_blocks_count(sb) * 100.0) /
 143                 ext2fs_blocks_count(sb);
 144
 145         retval = ext2fs_read_bitmaps(fs);
 146         if (retval)
 147                 return retval;
 148
 149         retval = ext2fs_dup_handle(fs, &new_fs);
 150         if (retval)
 151                 return retval;
 152
 153         /* The current method of adding one block group at a time to a
 154          * mounted filesystem means it is impossible to accomodate the
 155          * flex_bg allocation method of placing the metadata together
 156          * in a single block group.  For now we "fix" this issue by
 157          * using the traditional layout for new block groups, where
 158          * each block group is self-contained and contains its own
 159          * bitmap blocks and inode tables.  This means we don't get
 160          * the layout advantages of flex_bg in the new block groups,
 161          * but at least it allows on-line resizing to function.
 162          */
 163         new_fs->super->s_feature_incompat &= ~EXT4_FEATURE_INCOMPAT_FLEX_BG;
 164         retval = adjust_fs_info(new_fs, fs, 0, *new_size);
 165         if (retval)
 166                 return retval;
 167
 168         printf(_("Performing an on-line resize of %s to %llu (%dk) blocks.\n"),
 169                fs->device_name, *new_size, fs->blocksize / 1024);
 170
 171         size = fs->group_desc_count * sb->s_blocks_per_group +
 172                 sb->s_first_data_block;
 173         if (size > *new_size)
 174                 size = *new_size;
 175
 176         if (ioctl(fd, EXT2_IOC_GROUP_EXTEND, &size)) {
 177                 com_err(program_name, errno,
 178                         _("While trying to extend the last group"));
 179                 exit(1);
 180         }
 181
 182         for (i = fs->group_desc_count;
 183              i < new_fs->group_desc_count; i++) {
 184
 185                 overhead = (int) (2 + new_fs->inode_blocks_per_group);
 186
 187                 if (ext2fs_bg_has_super(new_fs, new_fs->group_desc_count - 1))
 188                         overhead += 1 + new_fs->desc_blocks +
 189                                 new_fs->super->s_reserved_gdt_blocks;
 190
 191                 input.group = i;
 192                 input.block_bitmap = ext2fs_block_bitmap_loc(new_fs, i);
 193                 input.inode_bitmap = ext2fs_inode_bitmap_loc(new_fs, i);
 194                 input.inode_table = ext2fs_inode_table_loc(new_fs, i);
 195                 input.blocks_count = ext2fs_group_blocks_count(new_fs, i);
 196                 input.reserved_blocks = (blk_t) (percent * input.blocks_count
 197                                                  / 100.0);
 198
 199 #if 0
 200                 printf("new block bitmap is at 0x%04x\n", input.block_bitmap);
 201                 printf("new inode bitmap is at 0x%04x\n", input.inode_bitmap);
 202                 printf("new inode table is at 0x%04x-0x%04x\n",
 203                        input.inode_table,
 204                        input.inode_table + new_fs->inode_blocks_per_group-1);
 205                 printf("new group has %u blocks\n", input.blocks_count);
 206                 printf("new group will reserve %d blocks\n",
 207                        input.reserved_blocks);
 208                 printf("new group has %d free blocks\n",
 209                        ext2fs_bg_free_blocks_count(new_fs, i),
 210                 printf("new group has %d free inodes (%d blocks)\n",
 211                        ext2fs_bg_free_inodes_count(new_fs, i),
 212                        new_fs->inode_blocks_per_group);
 213                 printf("Adding group #%d\n", input.group);
 214 #endif
 215
 216                 if (use_old_ioctl &&
 217                     ioctl(fd, EXT2_IOC_GROUP_ADD, &input) == 0)
 218                         continue;
 219                 else
 220                         use_old_ioctl = 0;
 221
 222                 input64.group = input.group;
 223                 input64.block_bitmap = input.block_bitmap;
 224                 input64.inode_bitmap = input.inode_bitmap;
 225                 input64.inode_table = input.inode_table;
 226                 input64.blocks_count = input.blocks_count;
 227                 input64.reserved_blocks = input.reserved_blocks;
 228                 input64.unused = input.unused;
 229
 230                 if (ioctl(fd, EXT4_IOC_GROUP_ADD, &input64) < 0) {
 231                         com_err(program_name, errno,
 232                                 _("While trying to add group #%d"),
 233                                 input.group);
 234                         exit(1);
 235                 }
 236         }
 237
 238         ext2fs_free(new_fs);
 239         close(fd);
 240
 241         return 0;
 242 #else
 243         printf(_("Filesystem at %s is mounted on %s, and on-line resizing is "
 244                  "not supported on this system.\n"), fs->device_name, mtpt);
 245         exit(1);
 246 #endif
 247 }