[PATCH] Avoid disk sector_t overflow for >2TB ext3 filesystem (fcd5df35) · Commits · 戴 / test

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 bytes. 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<cmm@us.ibm.com> Acked-by:

Andreas Dilger <adilger@clusterfs.com> Signed-off-by:

Andrew Morton <akpm@osdl.org> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

fs/ext3/resize.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -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");

fs/ext3/super.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -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 "
		"enabled\n");
		goto failed_mount;
		}

		if (EXT3_BLOCKS_PER_GROUP(sb) == 0)
		goto cantfind_ext3;
		sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -

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