Commit fcd5df35 authored by Mingming Cao's avatar Mingming Cao Committed by Linus Torvalds
Browse files

[PATCH] Avoid disk sector_t overflow for >2TB ext3 filesystem

If ext3 filesystem is larger than 2TB, and sector_t is a u32 (i.e.
CONFIG_LBD not defined in the kernel), the calculation of the disk sector
will overflow.  Add check at ext3_fill_super() and ext3_group_extend() to
prevent mount/remount/resize >2TB ext3 filesystem if sector_t size is 4

Verified this patch on a 32 bit platform without CONFIG_LBD defined
(sector_t is 32 bits long), mount refuse to mount a 10TB ext3.

Signed-off-by: Mingming Cao<>
Acked-by: default avatarAndreas Dilger <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent b6136773
......@@ -925,6 +925,16 @@ int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es,
if (n_blocks_count == 0 || n_blocks_count == o_blocks_count)
return 0;
if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
printk(KERN_ERR "EXT3-fs: filesystem on %s:"
" too large to resize to %lu blocks safely\n",
sb->s_id, n_blocks_count);
if (sizeof(sector_t) < 8)
ext3_warning(sb, __FUNCTION__,
"CONFIG_LBD not enabled\n");
return -EINVAL;
if (n_blocks_count < o_blocks_count) {
ext3_warning(sb, __FUNCTION__,
"can't shrink FS - resize aborted");
......@@ -1565,6 +1565,16 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
goto failed_mount;
if (le32_to_cpu(es->s_blocks_count) >
(sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) {
printk(KERN_ERR "EXT3-fs: filesystem on %s:"
" too large to mount safely\n", sb->s_id);
if (sizeof(sector_t) < 8)
printk(KERN_WARNING "EXT3-fs: CONFIG_LBD not "
goto failed_mount;
if (EXT3_BLOCKS_PER_GROUP(sb) == 0)
goto cantfind_ext3;
sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment