The patch titled
fix ext3 mounts at 16T
has been added to the -mm tree. Its filename is
fix-ext3-mounts-at-16t.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: fix ext3 mounts at 16T
From: Eric Sandeen <esandeen@xxxxxxxxxx>
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@xxxxxxxxxx>
Cc: Mingming Cao <cmm@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/ext3/super.c | 34 +++++++++++++++++++---------------
1 files changed, 19 insertions(+), 15 deletions(-)
diff -puN fs/ext3/super.c~fix-ext3-mounts-at-16t fs/ext3/super.c
--- a/fs/ext3/super.c~fix-ext3-mounts-at-16t
+++ a/fs/ext3/super.c
@@ -1132,7 +1132,8 @@ static int ext3_setup_super(struct super
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;
@@ -1141,12 +1142,17 @@ static int ext3_check_descriptors (struc
for (i = 0; i < sbi->s_groups_count; i++)
{
+ if (i == sbi->s_groups_count - 1)
+ last_block = 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"
@@ -1155,9 +1161,8 @@ static int ext3_check_descriptors (struc
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"
@@ -1166,9 +1171,9 @@ static int ext3_check_descriptors (struc
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"
@@ -1177,7 +1182,7 @@ static int ext3_check_descriptors (struc
le32_to_cpu(gdp->bg_inode_table));
return 0;
}
- block += EXT3_BLOCKS_PER_GROUP(sb);
+ first_block += EXT3_BLOCKS_PER_GROUP(sb);
gdp++;
}
@@ -1581,10 +1586,9 @@ static int ext3_fill_super (struct super
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 *),
_
Patches currently in -mm which might be from esandeen@xxxxxxxxxx are
mount-udf-udf_part_flag_read_only-partitions-with-ms_rdonly.patch
fix-ext3-mounts-at-16t.patch
-
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