Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>

When testing pnfs with nfsd_debug on, nfsd print a negative number
of layout length and foff in nfsd4_block_proc_layoutget as,
"GET: -xxxx:-xxx 2"
Signed-off-by: NKinglong Mee <kinglongmee@gmail.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

Add a small shim between core nfsd and filesystems to translate the
somewhat cumbersome pNFS data structures and semantics to something
more palatable for Linux filesystems.

Thanks to Rick McNeal for the old prototype pNFS blocklayout server
code, which gave a lot of inspiration to this version even if no
code is left from it.
Signed-off-by: NChristoph Hellwig <hch@lst.de>