[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/resize.c b/fs/ext3/resize.c
index 34b39e9..a31dff8 100644
--- a/fs/ext3/resize.c
+++ b/fs/ext3/resize.c
@@ -925,6 +925,16 @@
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");