[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
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>
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index a60cc6e..df98a77 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -1565,6 +1565,16 @@
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) -