> On Sep 1, 2022, at 2:33 PM, Anna Schumaker <anna@xxxxxxxxxx> wrote:
>
> Chuck, I tried to add in sparse read support by adding this extra
> change. Unfortunately it leads to a bunch of new failing xfstests. Do
> you have any thoughts about what might be going on? Is the patch okay
> without the splice support?
>
> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
> index adbff7737c14..e21e6cfd1c6d 100644
> --- a/fs/nfsd/nfs4xdr.c
> +++ b/fs/nfsd/nfs4xdr.c
> @@ -4733,6 +4733,7 @@ static __be32
> nfsd4_encode_read_plus_data(struct nfsd4_compoundres *resp,
> struct nfsd4_read *read)
> {
> + bool splice_ok = test_bit(RQ_SPLICE_OK, &resp->rqstp->rq_flags);
> unsigned long maxcount;
> struct xdr_stream *xdr = resp->xdr;
> struct file *file = read->rd_nf->nf_file;
> @@ -4747,7 +4748,10 @@ nfsd4_encode_read_plus_data(struct nfsd4_compoundres *resp,
> maxcount = min_t(unsigned long, read->rd_length,
> (xdr->buf->buflen - xdr->buf->len));
>
> - nfserr = nfsd4_encode_readv(resp, read, file, maxcount);
> + if (file->f_op->splice_read && splice_ok)
> + nfserr = nfsd4_encode_splice_read(resp, read, file, maxcount);
> + else
> + nfserr = nfsd4_encode_readv(resp, read, file, maxcount)
> if (nfserr)
> return nfserr;
I applied the above change to a test server, and was able to reproduce
a bunch of new test failures when using NFSv4.2. I confirmed using nfsd
tracepoints that splice read and READ_PLUS is being used.
I then expanded the test. When using an XFS-based export, I reproduced
the failures. But I was not able to reproduce these failures with
exports based on tmpfs, btrfs, or ext4. Again, I confirmed using nfsd
tracepoints that splice read was being used, and mountstats on my
client showed READ_PLUS is being used.
Then I tried testing the XFS-backed export with NFSv4.1, and found
that most of the failures appeared again. Once again, I confirmed
using nfsd tracepoints that splice read is being used during the tests.
Can you confirm that you see test failures with NFSv4.1 and XFS but
not with NFSv4.2 / READ_PLUS with btrfs, ext4, or tmpfs?
--
Chuck Lever
