> On Jun 8, 2016, at 10:45 AM, Benjamin Coddington <bcodding@xxxxxxxxxx> wrote:
>
> Hi Dros,
>
> The client takes this WARN_ON_ONCE path pretty often in
> pnfs_generic_pg_test() with SCSI layout type and generic/010:
>
> 1925 if (pgio->pg_lseg) {
> 1926 seg_end = end_offset(pgio->pg_lseg->pls_range.offset,
> 1927 pgio->pg_lseg->pls_range.length);
> 1928 req_start = req_offset(req);
> 1929 WARN_ON_ONCE(req_start >= seg_end);
> 1930 /* start of request is past the last byte of this segment */
> 1931 if (req_start >= seg_end) {
> 1932 /* reference the new lseg */
> 1933 if (pgio->pg_ops->pg_cleanup)
> 1934 pgio->pg_ops->pg_cleanup(pgio);
> 1935 if (pgio->pg_ops->pg_init)
> 1936 pgio->pg_ops->pg_init(pgio, req);
> 1937 return 0;
> 1938 }
>
> I'm trying to figure out why that's a WARN-able path.. do you recall the
> original reason for that warning?
What’s happening here is that the pgio descriptor spans multiple layout segments.
IIRC this points to a problem with the pg_test call. It shouldn’t allow requests
from different lsegs to be coalesced.
-dros
--
To unsubscribe from this list: send the line "unsubscribe linux-nfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
