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         if (EXT2_HAS_COMPAT_FEATURE(fs->super,
  80                                     EXT4_FEATURE_COMPAT_SPARSE_SUPER2) &&
  81             (access("/sys/fs/ext4/features/sparse_super2", R_OK) != 0)) {
  82                 com_err(program_name, 0, _("kernel does not support online "
  83                                            "resize with sparse_super2"));
  84                 exit(1);
  85         }
  86
  87         printf(_("Filesystem at %s is mounted on %s; "
  88                  "on-line resizing required\n"), fs->device_name, mtpt);
  89
  90         if (*new_size < ext2fs_blocks_count(sb)) {
  91                 com_err(program_name, 0, _("On-line shrinking not supported"));
  92                 exit(1);
  93         }
  94
  95         /*
  96          * If the number of descriptor blocks is going to increase,
  97          * the on-line resizing inode must be present.
  98          */
  99         new_desc_blocks = ext2fs_div_ceil(
 100                 ext2fs_div64_ceil(*new_size -
 101                                   fs->super->s_first_data_block,
 102                                   EXT2_BLOCKS_PER_GROUP(fs->super)),
 103                 EXT2_DESC_PER_BLOCK(fs->super));
 104         printf("old_desc_blocks = %lu, new_desc_blocks = %lu\n",
 105                fs->desc_blocks, new_desc_blocks);
 106
 107         /*
 108          * Do error checking to make sure the resize will be successful.
 109          */
 110         if ((access("/sys/fs/ext4/features/meta_bg_resize", R_OK) != 0) ||
 111             no_meta_bg_resize) {
 112                 if (!EXT2_HAS_COMPAT_FEATURE(fs->super,
 113                                         EXT2_FEATURE_COMPAT_RESIZE_INODE) &&
 114                     (new_desc_blocks != fs->desc_blocks)) {
 115                         com_err(program_name, 0,
 116                                 _("Filesystem does not support online resizing"));
 117                         exit(1);
 118                 }
 119
 120                 if (EXT2_HAS_COMPAT_FEATURE(fs->super,
 121                                         EXT2_FEATURE_COMPAT_RESIZE_INODE) &&
 122                     new_desc_blocks > (fs->desc_blocks +
 123                                        fs->super->s_reserved_gdt_blocks)) {
 124                         com_err(program_name, 0,
 125                                 _("Not enough reserved gdt blocks for resizing"));
 126                         exit(1);
 127                 }
 128
 129                 if ((ext2fs_blocks_count(sb) > MAX_32_NUM) ||
 130                     (*new_size > MAX_32_NUM)) {
 131                         com_err(program_name, 0,
 132                                 _("Kernel does not support resizing a file system this large"));
 133                         exit(1);
 134                 }
 135         }
 136
 137         fd = open(mtpt, O_RDONLY);
 138         if (fd < 0) {
 139                 com_err(program_name, errno,
 140                         _("while trying to open mountpoint %s"), mtpt);
 141                 exit(1);
 142         }
 143
 144         if (no_resize_ioctl) {
 145                 printf(_("Old resize interface requested.\n"));
 146         } else if (ioctl(fd, EXT4_IOC_RESIZE_FS, new_size)) {
 147                 /*
 148                  * If kernel does not support EXT4_IOC_RESIZE_FS, use the
 149                  * old online resize. Note that the old approach does not
 150                  * handle >32 bit file systems
 151                  *
 152                  * Sigh, if we are running a 32-bit binary on a 64-bit
 153                  * kernel (which happens all the time on the MIPS
 154                  * architecture in Debian, but can happen on other CPU
 155                  * architectures as well) we will get EINVAL returned
 156                  * when an ioctl doesn't exist, at least up to Linux
 157                  * 3.1.  See compat_sys_ioctl() in fs/compat_ioctl.c
 158                  * in the kernel sources.  This is probably a kernel
 159                  * bug, but work around it here.
 160                  */
 161                 if ((errno != ENOTTY) && (errno != EINVAL)) {
 162                         if (errno == EPERM)
 163                                 com_err(program_name, 0,
 164                                 _("Permission denied to resize filesystem"));
 165                         else
 166                                 com_err(program_name, errno,
 167                                 _("While checking for on-line resizing "
 168                                   "support"));
 169                         exit(1);
 170                 }
 171         } else {
 172                 close(fd);
 173                 return 0;
 174         }
 175
 176         size = ext2fs_blocks_count(sb);
 177
 178         if (ioctl(fd, EXT2_IOC_GROUP_EXTEND, &size)) {
 179                 if (errno == EPERM)
 180                         com_err(program_name, 0,
 181                                 _("Permission denied to resize filesystem"));
 182                 else if (errno == ENOTTY)
 183                         com_err(program_name, 0,
 184                         _("Kernel does not support online resizing"));
 185                 else
 186                         com_err(program_name, errno,
 187                         _("While checking for on-line resizing support"));
 188                 exit(1);
 189         }
 190
 191         percent = (ext2fs_r_blocks_count(sb) * 100.0) /
 192                 ext2fs_blocks_count(sb);
 193
 194         retval = ext2fs_read_bitmaps(fs);
 195         if (retval) {
 196                 close(fd);
 197                 return retval;
 198         }
 199
 200         retval = ext2fs_dup_handle(fs, &new_fs);
 201         if (retval) {
 202                 close(fd);
 203                 return retval;
 204         }
 205
 206         /* The current method of adding one block group at a time to a
 207          * mounted filesystem means it is impossible to accomodate the
 208          * flex_bg allocation method of placing the metadata together
 209          * in a single block group.  For now we "fix" this issue by
 210          * using the traditional layout for new block groups, where
 211          * each block group is self-contained and contains its own
 212          * bitmap blocks and inode tables.  This means we don't get
 213          * the layout advantages of flex_bg in the new block groups,
 214          * but at least it allows on-line resizing to function.
 215          */
 216         new_fs->super->s_feature_incompat &= ~EXT4_FEATURE_INCOMPAT_FLEX_BG;
 217         retval = adjust_fs_info(new_fs, fs, 0, *new_size);
 218         if (retval) {
 219                 close(fd);
 220                 return retval;
 221         }
 222
 223         printf(_("Performing an on-line resize of %s to %llu (%dk) blocks.\n"),
 224                fs->device_name, *new_size, fs->blocksize / 1024);
 225
 226         size = fs->group_desc_count * sb->s_blocks_per_group +
 227                 sb->s_first_data_block;
 228         if (size > *new_size)
 229                 size = *new_size;
 230
 231         if (ioctl(fd, EXT2_IOC_GROUP_EXTEND, &size)) {
 232                 com_err(program_name, errno,
 233                         _("While trying to extend the last group"));
 234                 exit(1);
 235         }
 236
 237         for (i = fs->group_desc_count;
 238              i < new_fs->group_desc_count; i++) {
 239
 240                 overhead = (int) (2 + new_fs->inode_blocks_per_group);
 241
 242                 if (ext2fs_bg_has_super(new_fs, new_fs->group_desc_count - 1))
 243                         overhead += 1 + new_fs->desc_blocks +
 244                                 new_fs->super->s_reserved_gdt_blocks;
 245
 246                 input.group = i;
 247                 input.block_bitmap = ext2fs_block_bitmap_loc(new_fs, i);
 248                 input.inode_bitmap = ext2fs_inode_bitmap_loc(new_fs, i);
 249                 input.inode_table = ext2fs_inode_table_loc(new_fs, i);
 250                 input.blocks_count = ext2fs_group_blocks_count(new_fs, i);
 251                 input.reserved_blocks = (blk_t) (percent * input.blocks_count
 252                                                  / 100.0);
 253
 254 #if 0
 255                 printf("new block bitmap is at 0x%04x\n", input.block_bitmap);
 256                 printf("new inode bitmap is at 0x%04x\n", input.inode_bitmap);
 257                 printf("new inode table is at 0x%04x-0x%04x\n",
 258                        input.inode_table,
 259                        input.inode_table + new_fs->inode_blocks_per_group-1);
 260                 printf("new group has %u blocks\n", input.blocks_count);
 261                 printf("new group will reserve %d blocks\n",
 262                        input.reserved_blocks);
 263                 printf("new group has %d free blocks\n",
 264                        ext2fs_bg_free_blocks_count(new_fs, i),
 265                 printf("new group has %d free inodes (%d blocks)\n",
 266                        ext2fs_bg_free_inodes_count(new_fs, i),
 267                        new_fs->inode_blocks_per_group);
 268                 printf("Adding group #%d\n", input.group);
 269 #endif
 270
 271                 if (use_old_ioctl &&
 272                     ioctl(fd, EXT2_IOC_GROUP_ADD, &input) == 0)
 273                         continue;
 274                 else
 275                         use_old_ioctl = 0;
 276
 277                 input64.group = input.group;
 278                 input64.block_bitmap = input.block_bitmap;
 279                 input64.inode_bitmap = input.inode_bitmap;
 280                 input64.inode_table = input.inode_table;
 281                 input64.blocks_count = input.blocks_count;
 282                 input64.reserved_blocks = input.reserved_blocks;
 283                 input64.unused = input.unused;
 284
 285                 if (ioctl(fd, EXT4_IOC_GROUP_ADD, &input64) < 0) {
 286                         com_err(program_name, errno,
 287                                 _("While trying to add group #%d"),
 288                                 input.group);
 289                         exit(1);
 290                 }
 291         }
 292
 293         ext2fs_free(new_fs);
 294         close(fd);
 295
 296         return 0;
 297 #else
 298         printf(_("Filesystem at %s is mounted on %s, and on-line resizing is "
 299                  "not supported on this system.\n"), fs->device_name, mtpt);
 300         exit(1);
 301 #endif
 302 }