On Wed, Apr 8, 2015 at 8:24 PM, Peng Tao <tao.peng@xxxxxxxxxxxxxxx> wrote:
> When adding completed bytes, we should just use hdr->good_bytes.
> Otherwise if we send multiple requests for one direct IO (due to
> rsize/wsize limitation), we'll count completed bytes incorrectly.
>
> This fixes 5fadeb47("nfs: count DIO good bytes correctly with mirroring").
>
> Reported-by: Jean Spector <jean@xxxxxxxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx> # v3.19+
> Signed-off-by: Peng Tao <tao.peng@xxxxxxxxxxxxxxx>
> ---
> fs/nfs/direct.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
> index e907c8c..645109e 100644
> --- a/fs/nfs/direct.c
> +++ b/fs/nfs/direct.c
> @@ -132,10 +132,8 @@ nfs_direct_good_bytes(struct nfs_direct_req *dreq, struct nfs_pgio_header *hdr)
> WARN_ON_ONCE(hdr->pgio_mirror_idx >= dreq->mirror_count);
>
> count = dreq->mirrors[hdr->pgio_mirror_idx].count;
> - if (count + dreq->io_start < hdr->io_start + hdr->good_bytes) {
> - count = hdr->io_start + hdr->good_bytes - dreq->io_start;
> - dreq->mirrors[hdr->pgio_mirror_idx].count = count;
> - }
> + if (count + dreq->io_start < hdr->io_start + hdr->good_bytes)
> + dreq->mirrors[hdr->pgio_mirror_idx].count += hdr->good_bytes;
oh, speaking too soon. This would actually fail concurrent DIO writers
if split requests complete randomly. Please don't merge it! I'll send
a updated version. sorry for the noise!
Thanks,
Tao
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html