[Ocfs2-devel] [PATCH 1/1] ocfs2: validate bg_free_bits_count after update
Sunil Mushran
sunil.mushran at oracle.com
Mon Oct 4 14:56:22 PDT 2010
It think it should return -EROFS.
Also, change >= to >. I don't think this error message needs to know
that 1 bit is consumed by the header.
Rest looks good.
On 10/01/2010 01:53 PM, Srinivas Eeda wrote:
> This patch adds a safe check to ensure bg_free_bits_count doesn't exceed
> bg_bits in a group descriptor. This is to avoid on disk corruption that was
> seen recently.
>
> debugfs: group<52803072>
> Group Chain: 179 Parent Inode: 11 Generation: 2959379682
> CRC32: 00000000 ECC: 0000
> ## Block# Total Used Free Contig Size
> 0 52803072 32256 4294965350 34202 18207 4032
> ......
>
> Signed-off-by: Srinivas Eeda<srinivas.eeda at oracle.com>
> ---
> fs/ocfs2/suballoc.c | 16 ++++++++++++++++
> 1 files changed, 16 insertions(+), 0 deletions(-)
>
> diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
> index 849c2f0..d606a79 100644
> --- a/fs/ocfs2/suballoc.c
> +++ b/fs/ocfs2/suballoc.c
> @@ -1380,6 +1380,14 @@ static inline int ocfs2_block_group_set_bits(handle_t *handle,
> }
>
> le16_add_cpu(&bg->bg_free_bits_count, -num_bits);
> + if (le16_to_cpu(bg->bg_free_bits_count)>= le16_to_cpu(bg->bg_bits)) {
> + ocfs2_error(alloc_inode->i_sb, "Group descriptor # %llu has bit"
> + " count %u but claims %u are freed. num_bits %d",
> + (unsigned long long)le64_to_cpu(bg->bg_blkno),
> + le16_to_cpu(bg->bg_bits),
> + le16_to_cpu(bg->bg_free_bits_count), num_bits);
> + return -EIO;
> + }
> while(num_bits--)
> ocfs2_set_bit(bit_off++, bitmap);
>
> @@ -2419,6 +2427,14 @@ static int ocfs2_block_group_clear_bits(handle_t *handle,
> (unsigned long *) undo_bg->bg_bitmap);
> }
> le16_add_cpu(&bg->bg_free_bits_count, num_bits);
> + if (le16_to_cpu(bg->bg_free_bits_count)>= le16_to_cpu(bg->bg_bits)) {
> + ocfs2_error(alloc_inode->i_sb, "Group descriptor # %llu has bit"
> + " count %u but claims %u are freed. num_bits %d",
> + (unsigned long long)le64_to_cpu(bg->bg_blkno),
> + le16_to_cpu(bg->bg_bits),
> + le16_to_cpu(bg->bg_free_bits_count), num_bits);
> + return -EIO;
> + }
>
> if (undo_fn)
> jbd_unlock_bh_state(group_bh);
>
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