On Mon, Oct 17, 2011 at 4:45 PM, Tao Ma <tm@xxxxxx> wrote:
> From: Tao Ma <boyu.mt@xxxxxxxxxx>
>
> In 4fd30c033, we move the range check before we change ix to avoid the memory stamp.
> But actually we should check against the EXT_MAX_INDEX, not EXT_LAST_INDEX.
>
> So this patch revert the old patch and adds a new check before we setting ix.
>
> Cc: "Theodore Ts'o" <tytso@xxxxxxx>
> Signed-off-by: Tao Ma <boyu.mt@xxxxxxxxxx>
> ---
> Ted, since 4fd30c033 is in your dev branch, I am fine to integrate these 2 patches to one.
>
> fs/ext4/extents.c | 9 +++++++--
> 1 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 2dff31e..5c48612 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -779,8 +779,8 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
> ix = curp->p_idx;
> }
>
> - if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) {
> - EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
> + if (unlikely(ix > EXT_MAX_INDEX(curp->p_hdr))) {
> + EXT4_ERROR_INODE(inode, "ix > EXT_MAX_INDEX!");
> return -EIO;
> }
Hi Tao,
I think original LAST_INDEX check aims to verify all index entries are
contiguous, because max entries bas been checked by eh_entries >=
ex_max in previous code.
>
> @@ -788,6 +788,11 @@ 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(ix > EXT_LAST_INDEX(curp->p_hdr))) {
> + EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!");
> + return -EIO;
> + }
> +
Actually I do not think we need a verification here. The code is
short and we know that index entries are contiguous.
Yongqiang.
> err = ext4_ext_dirty(handle, inode, curp);
> ext4_std_error(inode->i_sb, err);
>
> --
> 1.6.3.3.334.g916e1.dirty
>
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--
Best Wishes
Yongqiang Yang
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