On Friday 2 October 2020 10:19:24 AM IST Darrick J. Wong wrote:
> From: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
>
> If userspace asked fsmap to count the number of entries, we cannot
> return more than UINT_MAX entries because fmh_entries is u32.
> Therefore, stop counting if we hit this limit or else we will waste time
> to return truncated results.
>
> Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl")
> Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
The upper bound check is correct.
Reviewed-by: Chandan Babu R <chandanrlinux@xxxxxxxxx>
> ---
> fs/xfs/xfs_fsmap.c | 3 +++
> 1 file changed, 3 insertions(+)
>
>
> diff --git a/fs/xfs/xfs_fsmap.c b/fs/xfs/xfs_fsmap.c
> index 4eebcec4aae6..aa36e7daf82c 100644
> --- a/fs/xfs/xfs_fsmap.c
> +++ b/fs/xfs/xfs_fsmap.c
> @@ -256,6 +256,9 @@ xfs_getfsmap_helper(
>
> /* Are we just counting mappings? */
> if (info->head->fmh_count == 0) {
> + if (info->head->fmh_entries == UINT_MAX)
> + return -ECANCELED;
> +
> if (rec_daddr > info->next_daddr)
> info->head->fmh_entries++;
>
>
>
--
chandan
