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authorEric Sandeen <esandeen@redhat.com>2006-09-27 01:49:29 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-27 08:26:09 -0700
commit855565e81ad8940cc645b5110ec2c7f124a76d23 (patch)
tree48b5ff0eb7bd297404b301e679d6330976e3e90d /fs/ext3
parent2aed3484695ecb03f1395bb62f1099e8b0826124 (diff)
[PATCH] fix ext3 mounts at 16T
I need to do some actual IO testing now, but this gets things mounting for a 16T ext3 filesystem. (patched up e2fsprogs is needed too, I'll send that off the kernel list) This patch fixes these issues in the kernel: o sbi->s_groups_count overflows in ext3_fill_super() 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) / EXT3_BLOCKS_PER_GROUP(sb); at 16T, s_blocks_count is already maxed out; adding EXT3_BLOCKS_PER_GROUP(sb) overflows it and groups_count comes out to 0. Not really what we want, and causes a failed mount. Feel free to check my math (actually, please do!), but changing it this way should work & avoid the overflow: (A + B - 1)/B changed to: ((A - 1)/B) + 1 o ext3_check_descriptors() overflows range checks ext3_check_descriptors() iterates over all block groups making sure that various bits are within the right block ranges... on the last pass through, it is checking the error case [item] >= block + EXT3_BLOCKS_PER_GROUP(sb) where "block" is the first block in the last block group. The last block in this group (and the last one that will fit in 32 bits) is block + EXT3_BLOCKS_PER_GROUP(sb)- 1. block + EXT3_BLOCKS_PER_GROUP(sb) wraps back around to 0. so, make things clearer with "first_block" and "last_block" where those are first and last, inclusive, and use <, > rather than <, >=. Finally, the last block group may be smaller than the rest, so account for this on the last pass through: last_block = sb->s_blocks_count - 1; (a similar patch could be done for ext2; does anyone in their right mind use ext2 at 16T? I'll send an ext2 patch doing the same thing if that's warranted) Signed-off-by: Eric Sandeen <esandeen@redhat.com> Cc: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/ext3')
-rw-r--r--fs/ext3/super.c34
1 files changed, 19 insertions, 15 deletions
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index 4b95bfe4c8f..762dff7b56f 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -1174,7 +1174,8 @@ static int ext3_setup_super(struct super_block *sb, struct ext3_super_block *es,
static int ext3_check_descriptors (struct super_block * sb)
{
struct ext3_sb_info *sbi = EXT3_SB(sb);
- ext3_fsblk_t block = le32_to_cpu(sbi->s_es->s_first_data_block);
+ ext3_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block);
+ ext3_fsblk_t last_block;
struct ext3_group_desc * gdp = NULL;
int desc_block = 0;
int i;
@@ -1183,12 +1184,17 @@ static int ext3_check_descriptors (struct super_block * sb)
for (i = 0; i < sbi->s_groups_count; i++)
{
+ if (i == sbi->s_groups_count - 1)
+ last_block = le32_to_cpu(sbi->s_es->s_blocks_count) - 1;
+ else
+ last_block = first_block +
+ (EXT3_BLOCKS_PER_GROUP(sb) - 1);
+
if ((i % EXT3_DESC_PER_BLOCK(sb)) == 0)
gdp = (struct ext3_group_desc *)
sbi->s_group_desc[desc_block++]->b_data;
- if (le32_to_cpu(gdp->bg_block_bitmap) < block ||
- le32_to_cpu(gdp->bg_block_bitmap) >=
- block + EXT3_BLOCKS_PER_GROUP(sb))
+ if (le32_to_cpu(gdp->bg_block_bitmap) < first_block ||
+ le32_to_cpu(gdp->bg_block_bitmap) > last_block)
{
ext3_error (sb, "ext3_check_descriptors",
"Block bitmap for group %d"
@@ -1197,9 +1203,8 @@ static int ext3_check_descriptors (struct super_block * sb)
le32_to_cpu(gdp->bg_block_bitmap));
return 0;
}
- if (le32_to_cpu(gdp->bg_inode_bitmap) < block ||
- le32_to_cpu(gdp->bg_inode_bitmap) >=
- block + EXT3_BLOCKS_PER_GROUP(sb))
+ if (le32_to_cpu(gdp->bg_inode_bitmap) < first_block ||
+ le32_to_cpu(gdp->bg_inode_bitmap) > last_block)
{
ext3_error (sb, "ext3_check_descriptors",
"Inode bitmap for group %d"
@@ -1208,9 +1213,9 @@ static int ext3_check_descriptors (struct super_block * sb)
le32_to_cpu(gdp->bg_inode_bitmap));
return 0;
}
- if (le32_to_cpu(gdp->bg_inode_table) < block ||
- le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >=
- block + EXT3_BLOCKS_PER_GROUP(sb))
+ if (le32_to_cpu(gdp->bg_inode_table) < first_block ||
+ le32_to_cpu(gdp->bg_inode_table) + sbi->s_itb_per_group >
+ last_block)
{
ext3_error (sb, "ext3_check_descriptors",
"Inode table for group %d"
@@ -1219,7 +1224,7 @@ static int ext3_check_descriptors (struct super_block * sb)
le32_to_cpu(gdp->bg_inode_table));
return 0;
}
- block += EXT3_BLOCKS_PER_GROUP(sb);
+ first_block += EXT3_BLOCKS_PER_GROUP(sb);
gdp++;
}
@@ -1622,10 +1627,9 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
if (EXT3_BLOCKS_PER_GROUP(sb) == 0)
goto cantfind_ext3;
- 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) /
- EXT3_BLOCKS_PER_GROUP(sb);
+ sbi->s_groups_count = ((le32_to_cpu(es->s_blocks_count) -
+ le32_to_cpu(es->s_first_data_block) - 1)
+ / EXT3_BLOCKS_PER_GROUP(sb)) + 1;
db_count = (sbi->s_groups_count + EXT3_DESC_PER_BLOCK(sb) - 1) /
EXT3_DESC_PER_BLOCK(sb);
sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),