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 #ifdef __linux__
  25 static int parse_version_number(const char *s)
  26 {
  27         int     major, minor, rev;
  28         char    *endptr;
  29         const char *cp = s;
  30
  31         if (!s)
  32                 return 0;
  33         major = strtol(cp, &endptr, 10);
  34         if (cp == endptr || *endptr != '.')
  35                 return 0;
  36         cp = endptr + 1;
  37         minor = strtol(cp, &endptr, 10);
  38         if (cp == endptr || *endptr != '.')
  39                 return 0;
  40         cp = endptr + 1;
  41         rev = strtol(cp, &endptr, 10);
  42         if (cp == endptr)
  43                 return 0;
  44         return ((((major * 256) + minor) * 256) + rev);
  45 }
  46
  47 #define VERSION_CODE(a,b,c) (((a) << 16) + ((b) << 8) + (c))
  48
  49 #endif
  50
  51 errcode_t online_resize_fs(ext2_filsys fs, const char *mtpt,
  52                            blk64_t *new_size, int flags EXT2FS_ATTR((unused)))
  53 {
  54 #ifdef __linux__
  55         struct ext2_new_group_input input;
  56         struct ext4_new_group_input input64;
  57         struct ext2_super_block *sb = fs->super;
  58         unsigned long           new_desc_blocks;
  59         ext2_filsys             new_fs;
  60         errcode_t               retval;
  61         double                  percent;
  62         dgrp_t                  i;
  63         blk_t                   size;
  64         int                     fd, overhead;
  65         int                     use_old_ioctl = 1;
  66         int                     no_meta_bg_resize = 0;
  67         int                     no_resize_ioctl = 0;
  68
  69         if (getenv("RESIZE2FS_KERNEL_VERSION")) {
  70                 char *version_to_emulate = getenv("RESIZE2FS_KERNEL_VERSION");
  71                 int kvers = parse_version_number(version_to_emulate);
  72
  73                 if (kvers < VERSION_CODE(3, 7, 0))
  74                         no_meta_bg_resize = 1;
  75                 if (kvers < VERSION_CODE(3, 3, 0))
  76                         no_resize_ioctl = 1;
  77         }
  78
  79         printf(_("Filesystem at %s is mounted on %s; "
  80                  "on-line resizing required\n"), fs->device_name, mtpt);
  81
  82         if (*new_size < ext2fs_blocks_count(sb)) {
  83                 com_err(program_name, 0, _("On-line shrinking not supported"));
  84                 exit(1);
  85         }
  86
  87         /*
  88          * If the number of descriptor blocks is going to increase,
  89          * the on-line resizing inode must be present.
  90          */
  91         new_desc_blocks = ext2fs_div_ceil(
  92                 ext2fs_div64_ceil(*new_size -
  93                                   fs->super->s_first_data_block,
  94                                   EXT2_BLOCKS_PER_GROUP(fs->super)),
  95                 EXT2_DESC_PER_BLOCK(fs->super));
  96         printf("old_desc_blocks = %lu, new_desc_blocks = %lu\n",
  97                fs->desc_blocks, new_desc_blocks);
  98
  99         /*
 100          * Do error checking to make sure the resize will be successful.
 101          */
 102         if ((access("/sys/fs/ext4/features/meta_bg_resize", R_OK) != 0) ||
 103             no_meta_bg_resize) {
 104                 if (!EXT2_HAS_COMPAT_FEATURE(fs->super,
 105                                         EXT2_FEATURE_COMPAT_RESIZE_INODE) &&
 106                     (new_desc_blocks != fs->desc_blocks)) {
 107                         com_err(program_name, 0,
 108                                 _("Filesystem does not support online resizing"));
 109                         exit(1);
 110                 }
 111
 112                 if (EXT2_HAS_COMPAT_FEATURE(fs->super,
 113                                         EXT2_FEATURE_COMPAT_RESIZE_INODE) &&
 114                     new_desc_blocks > (fs->desc_blocks +
 115                                        fs->super->s_reserved_gdt_blocks)) {
 116                         com_err(program_name, 0,
 117                                 _("Not enough reserved gdt blocks for resizing"));
 118                         exit(1);
 119                 }
 120
 121                 if ((ext2fs_blocks_count(sb) > MAX_32_NUM) ||
 122                     (*new_size > MAX_32_NUM)) {
 123                         com_err(program_name, 0,
 124                                 _("Kernel does not support resizing a file system this large"));
 125                         exit(1);
 126                 }
 127         }
 128
 129         fd = open(mtpt, O_RDONLY);
 130         if (fd < 0) {
 131                 com_err(program_name, errno,
 132                         _("while trying to open mountpoint %s"), mtpt);
 133                 exit(1);
 134         }
 135
 136         if (no_resize_ioctl) {
 137                 printf(_("Old resize interface requested.\n"));
 138         } else if (ioctl(fd, EXT4_IOC_RESIZE_FS, new_size)) {
 139                 /*
 140                  * If kernel does not support EXT4_IOC_RESIZE_FS, use the
 141                  * old online resize. Note that the old approach does not
 142                  * handle >32 bit file systems
 143                  *
 144                  * Sigh, if we are running a 32-bit binary on a 64-bit
 145                  * kernel (which happens all the time on the MIPS
 146                  * architecture in Debian, but can happen on other CPU
 147                  * architectures as well) we will get EINVAL returned
 148                  * when an ioctl doesn't exist, at least up to Linux
 149                  * 3.1.  See compat_sys_ioctl() in fs/compat_ioctl.c
 150                  * in the kernel sources.  This is probably a kernel
 151                  * bug, but work around it here.
 152                  */
 153                 if ((errno != ENOTTY) && (errno != EINVAL)) {
 154                         if (errno == EPERM)
 155                                 com_err(program_name, 0,
 156                                 _("Permission denied to resize filesystem"));
 157                         else
 158                                 com_err(program_name, errno,
 159                                 _("While checking for on-line resizing "
 160                                   "support"));
 161                         exit(1);
 162                 }
 163         } else {
 164                 close(fd);
 165                 return 0;
 166         }
 167
 168         size = ext2fs_blocks_count(sb);
 169
 170         if (ioctl(fd, EXT2_IOC_GROUP_EXTEND, &size)) {
 171                 if (errno == EPERM)
 172                         com_err(program_name, 0,
 173                                 _("Permission denied to resize filesystem"));
 174                 else if (errno == ENOTTY)
 175                         com_err(program_name, 0,
 176                         _("Kernel does not support online resizing"));
 177                 else
 178                         com_err(program_name, errno,
 179                         _("While checking for on-line resizing support"));
 180                 exit(1);
 181         }
 182
 183         percent = (ext2fs_r_blocks_count(sb) * 100.0) /
 184                 ext2fs_blocks_count(sb);
 185
 186         retval = ext2fs_read_bitmaps(fs);
 187         if (retval)
 188                 return retval;
 189
 190         retval = ext2fs_dup_handle(fs, &new_fs);
 191         if (retval)
 192                 return retval;
 193
 194         /* The current method of adding one block group at a time to a
 195          * mounted filesystem means it is impossible to accomodate the
 196          * flex_bg allocation method of placing the metadata together
 197          * in a single block group.  For now we "fix" this issue by
 198          * using the traditional layout for new block groups, where
 199          * each block group is self-contained and contains its own
 200          * bitmap blocks and inode tables.  This means we don't get
 201          * the layout advantages of flex_bg in the new block groups,
 202          * but at least it allows on-line resizing to function.
 203          */
 204         new_fs->super->s_feature_incompat &= ~EXT4_FEATURE_INCOMPAT_FLEX_BG;
 205         retval = adjust_fs_info(new_fs, fs, 0, *new_size);
 206         if (retval)
 207                 return retval;
 208
 209         printf(_("Performing an on-line resize of %s to %llu (%dk) blocks.\n"),
 210                fs->device_name, *new_size, fs->blocksize / 1024);
 211
 212         size = fs->group_desc_count * sb->s_blocks_per_group +
 213                 sb->s_first_data_block;
 214         if (size > *new_size)
 215                 size = *new_size;
 216
 217         if (ioctl(fd, EXT2_IOC_GROUP_EXTEND, &size)) {
 218                 com_err(program_name, errno,
 219                         _("While trying to extend the last group"));
 220                 exit(1);
 221         }
 222
 223         for (i = fs->group_desc_count;
 224              i < new_fs->group_desc_count; i++) {
 225
 226                 overhead = (int) (2 + new_fs->inode_blocks_per_group);
 227
 228                 if (ext2fs_bg_has_super(new_fs, new_fs->group_desc_count - 1))
 229                         overhead += 1 + new_fs->desc_blocks +
 230                                 new_fs->super->s_reserved_gdt_blocks;
 231
 232                 input.group = i;
 233                 input.block_bitmap = ext2fs_block_bitmap_loc(new_fs, i);
 234                 input.inode_bitmap = ext2fs_inode_bitmap_loc(new_fs, i);
 235                 input.inode_table = ext2fs_inode_table_loc(new_fs, i);
 236                 input.blocks_count = ext2fs_group_blocks_count(new_fs, i);
 237                 input.reserved_blocks = (blk_t) (percent * input.blocks_count
 238                                                  / 100.0);
 239
 240 #if 0
 241                 printf("new block bitmap is at 0x%04x\n", input.block_bitmap);
 242                 printf("new inode bitmap is at 0x%04x\n", input.inode_bitmap);
 243                 printf("new inode table is at 0x%04x-0x%04x\n",
 244                        input.inode_table,
 245                        input.inode_table + new_fs->inode_blocks_per_group-1);
 246                 printf("new group has %u blocks\n", input.blocks_count);
 247                 printf("new group will reserve %d blocks\n",
 248                        input.reserved_blocks);
 249                 printf("new group has %d free blocks\n",
 250                        ext2fs_bg_free_blocks_count(new_fs, i),
 251                 printf("new group has %d free inodes (%d blocks)\n",
 252                        ext2fs_bg_free_inodes_count(new_fs, i),
 253                        new_fs->inode_blocks_per_group);
 254                 printf("Adding group #%d\n", input.group);
 255 #endif
 256
 257                 if (use_old_ioctl &&
 258                     ioctl(fd, EXT2_IOC_GROUP_ADD, &input) == 0)
 259                         continue;
 260                 else
 261                         use_old_ioctl = 0;
 262
 263                 input64.group = input.group;
 264                 input64.block_bitmap = input.block_bitmap;
 265                 input64.inode_bitmap = input.inode_bitmap;
 266                 input64.inode_table = input.inode_table;
 267                 input64.blocks_count = input.blocks_count;
 268                 input64.reserved_blocks = input.reserved_blocks;
 269                 input64.unused = input.unused;
 270
 271                 if (ioctl(fd, EXT4_IOC_GROUP_ADD, &input64) < 0) {
 272                         com_err(program_name, errno,
 273                                 _("While trying to add group #%d"),
 274                                 input.group);
 275                         exit(1);
 276                 }
 277         }
 278
 279         ext2fs_free(new_fs);
 280         close(fd);
 281
 282         return 0;
 283 #else
 284         printf(_("Filesystem at %s is mounted on %s, and on-line resizing is "
 285                  "not supported on this system.\n"), fs->device_name, mtpt);
 286         exit(1);
 287 #endif
 288 }