ext3-sector_t-overflow-2.6.9-rhel4.patch

非常经典的一个分布式系统

Subject: Avoid disk sector_t overflow for >2TB ext3 filesystem
From: Mingming Cao <[e-mail]>


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<[e-mail]>
Acked-by: Andreas Dilger <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 fs/ext3/resize.c |   10 ++++++++++
 fs/ext3/super.c  |   10 ++++++++++
 2 files changed, 20 insertions(+)

diff -puN fs/ext3/resize.c~avoid-disk-sector_t-overflow-for-2tb-ext3-filesystem fs/ext3/resize.c
--- devel/fs/ext3/resize.c~avoid-disk-sector_t-overflow-for-2tb-ext3-filesystem	2006-05-22 14:09:53.000000000 -0700
+++ devel-akpm/fs/ext3/resize.c	2006-05-22 14:10:56.000000000 -0700
@@ -926,6 +926,16 @@ int ext3_group_extend(struct super_block
 	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");
diff -puN fs/ext3/super.c~avoid-disk-sector_t-overflow-for-2tb-ext3-filesystem fs/ext3/super.c
--- devel/fs/ext3/super.c~avoid-disk-sector_t-overflow-for-2tb-ext3-filesystem	2006-05-22 14:09:53.000000000 -0700
+++ devel-akpm/fs/ext3/super.c	2006-05-22 14:11:10.000000000 -0700
@@ -1565,6 +1565,17 @@ static int ext3_fill_super (struct super
 		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 - %u blocks\n", sb->s_id,
+		       le32_to_cpu(es->s_blocks_count));
+		if (sizeof(sector_t) < 8)
+			printk(KERN_WARNING
+			       "EXT3-fs: CONFIG_LBD not enabled\n");
+		goto failed_mount;
+	}
+
 	sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -
 			       le32_to_cpu(es->s_first_data_block) +
 			       EXT3_BLOCKS_PER_GROUP(sb) - 1) /
_