On 6/23/11 3:47 AM, Robin Dong wrote:
> If eh_entries is equal to (or greater than) eh_max, the operation of
> inserting new extent_idx will make number of entries overflow.
> So check eh_entries before inserting the new extent_idx.
Do you have any testcase you can share which shows this bug?
Thanks,
-Eric
> Signed-off-by: Robin Dong <sanbai@xxxxxxxxxx>
> ---
> fs/ext4/extents.c | 18 ++++++++++--------
> 1 files changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index eb63c7b..792e77e 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -776,6 +776,16 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
> logical, le32_to_cpu(curp->p_idx->ei_block));
> return -EIO;
> }
> +
> + if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
> + >= le16_to_cpu(curp->p_hdr->eh_max))) {
> + EXT4_ERROR_INODE(inode,
> + "eh_entries %d >= eh_max %d!",
> + le16_to_cpu(curp->p_hdr->eh_entries),
> + le16_to_cpu(curp->p_hdr->eh_max));
> + return -EIO;
> + }
> +
> len = EXT_MAX_INDEX(curp->p_hdr) - curp->p_idx;
> if (logical > le32_to_cpu(curp->p_idx->ei_block)) {
> /* insert after */
> @@ -805,14 +815,6 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
> ext4_idx_store_pblock(ix, ptr);
> le16_add_cpu(&curp->p_hdr->eh_entries, 1);
>
> - if (unlikely(le16_to_cpu(curp->p_hdr->eh_entries)
> - > le16_to_cpu(curp->p_hdr->eh_max))) {
> - EXT4_ERROR_INODE(inode,
> - "eh_entries %d > eh_max %d!",
> - le16_to_cpu(curp->p_hdr->eh_entries),
> - le16_to_cpu(curp->p_hdr->eh_max));
> - return -EIO;
> - }
> if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
> EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
> return -EIO;
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