This is a note to let you know that I've just added the patch titled
ext4: fix the free blocks calculation for ext3 file systems w/ uninit_bg
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-fix-the-free-blocks-calculation-for-ext3-file-systems-w-uninit_bg.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From b0dd6b70f0fda17ae9762fbb72d98e40a4f66556 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <[email protected]>
Date: Thu, 7 Jun 2012 18:56:06 -0400
Subject: ext4: fix the free blocks calculation for ext3 file systems w/
uninit_bg
From: Theodore Ts'o <[email protected]>
commit b0dd6b70f0fda17ae9762fbb72d98e40a4f66556 upstream.
Ext3 filesystems that are converted to use as many ext4 file system
features as possible will enable uninit_bg to speed up e2fsck times.
These file systems will have a native ext3 layout of inode tables and
block allocation bitmaps (as opposed to ext4's flex_bg layout).
Unfortunately, in these cases, when first allocating a block in an
uninitialized block group, ext4 would incorrectly calculate the number
of free blocks in that block group, and then errorneously report that
the file system was corrupt:
EXT4-fs error (device vdd): ext4_mb_generate_buddy:741: group 30, 32254
clusters in bitmap, 32258 in gd
This problem can be reproduced via:
mke2fs -q -t ext4 -O ^flex_bg /dev/vdd 5g
mount -t ext4 /dev/vdd /mnt
fallocate -l 4600m /mnt/test
The problem was caused by a bone headed mistake in the check to see if a
particular metadata block was part of the block group.
Many thanks to Kees Cook for finding and bisecting the buggy commit
which introduced this bug (commit fd034a84e1, present since v3.2).
Reported-by: Sander Eikelenboom <[email protected]>
Reported-by: Kees Cook <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>
Tested-by: Kees Cook <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/ext4/balloc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -90,8 +90,8 @@ unsigned ext4_num_overhead_clusters(stru
* unusual file system layouts.
*/
if (ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp), block_group)) {
- block_cluster = EXT4_B2C(sbi, (start -
- ext4_block_bitmap(sb, gdp)));
+ block_cluster = EXT4_B2C(sbi,
+ ext4_block_bitmap(sb, gdp) - start);
if (block_cluster < num_clusters)
block_cluster = -1;
else if (block_cluster == num_clusters) {
@@ -102,7 +102,7 @@ unsigned ext4_num_overhead_clusters(stru
if (ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp), block_group)) {
inode_cluster = EXT4_B2C(sbi,
- start - ext4_inode_bitmap(sb, gdp));
+ ext4_inode_bitmap(sb, gdp) - start);
if (inode_cluster < num_clusters)
inode_cluster = -1;
else if (inode_cluster == num_clusters) {
@@ -114,7 +114,7 @@ unsigned ext4_num_overhead_clusters(stru
itbl_blk = ext4_inode_table(sb, gdp);
for (i = 0; i < sbi->s_itb_per_group; i++) {
if (ext4_block_in_group(sb, itbl_blk + i, block_group)) {
- c = EXT4_B2C(sbi, start - itbl_blk + i);
+ c = EXT4_B2C(sbi, itbl_blk + i - start);
if ((c < num_clusters) || (c == inode_cluster) ||
(c == block_cluster) || (c == itbl_cluster))
continue;
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/ext4-fix-the-free-blocks-calculation-for-ext3-file-systems-w-uninit_bg.patch
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