nfsd: fix nfs read eof detection

Currently, the knfsd server assumes that a short read indicates an
end of file. That assumption is incorrect. The short read means that
either we've hit the end of file, or we've hit a read error.

In the case of a read error, the client may want to retry (as per the
implementation recommendations in RFC1813 and RFC7530), but currently it
is being told that it hit an eof.

Move the code to detect eof from version specific code into the generic
nfsd read.

Report eof only in the two following cases:
1) read() returns a zero length short read with no error.
2) the offset+length of the read is >= the file size.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h
index 2cb29e961a76..99ff9f403ff1 100644
--- a/fs/nfsd/xdr3.h
+++ b/fs/nfsd/xdr3.h
@@ -151,7 +151,7 @@ struct nfsd3_readres {
 	__be32			status;
 	struct svc_fh		fh;
 	unsigned long		count;
-	int			eof;
+	__u32			eof;
 };
 
 struct nfsd3_writeres {