On Wed, Apr 08, 2020 at 11:36:16AM +0100, fdmanana@xxxxxxxxxx wrote:
> From: Filipe Manana <fdmanana@xxxxxxxx>
>
> While running generic/521 I've had fsx taking a lot of CPU time and not
> making any progress for several hours. Attaching gdb to the fsx process
> revealed that fsx was in the loop that generates the ranges for a
> copy_file_range operation, in particular the loop seemed to never end
> because the range defined by 'offset2' kept overlapping with the range
> defined by 'offset'.
> So far this happened one time only in one of my test VMs with generic/521.
>
> Fix this by breaking out of the loop after trying 30 times, like we
> currently do for dedupe operations, which results in logging the operation
> as skipped.
>
> Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
> ---
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
> ltp/fsx.c | 30 +++++++++++++++++++-----------
> 1 file changed, 19 insertions(+), 11 deletions(-)
>
> diff --git a/ltp/fsx.c b/ltp/fsx.c
> index 5949ebf0..89a5f60e 100644
> --- a/ltp/fsx.c
> +++ b/ltp/fsx.c
> @@ -2042,17 +2042,25 @@ test(void)
> break;
> }
> case OP_COPY_RANGE:
> - TRIM_OFF_LEN(offset, size, file_size);
> - offset -= offset % readbdy;
> - if (o_direct)
> - size -= size % readbdy;
> - do {
> - offset2 = random();
> - TRIM_OFF(offset2, maxfilelen);
> - offset2 -= offset2 % writebdy;
> - } while (range_overlaps(offset, offset2, size) ||
> - offset2 + size > maxfilelen);
> - break;
> + {
> + int tries = 0;
> +
> + TRIM_OFF_LEN(offset, size, file_size);
> + offset -= offset % readbdy;
> + if (o_direct)
> + size -= size % readbdy;
> + do {
> + if (tries++ >= 30) {
> + size = 0;
> + break;
> + }
> + offset2 = random();
> + TRIM_OFF(offset2, maxfilelen);
> + offset2 -= offset2 % writebdy;
> + } while (range_overlaps(offset, offset2, size) ||
> + offset2 + size > maxfilelen);
> + break;
> + }
> }
>
> have_op:
> --
> 2.11.0
>
