Received-SPF: pass (google.com: domain of linux-nfs-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Sender: Chuck Lever <chucklever@gmail.com>
Subject: [PATCH v2 001/118] NFSD: Fix returned READDIR offset cookie
From:   Chuck Lever <chuck.lever@oracle.com>
To:     linux-nfs@vger.kernel.org
Date:   Fri, 20 Nov 2020 15:33:51 -0500
Message-ID: <160590443133.1340.6772360578279663543.stgit@klimt.1015granger.net>
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Code inspection shows that the server's NFSv3 READDIR implementation
returns the same offset cookie as the client sent, instead of the
last cookie it returns in the reply's dirlist. This is unlike the
NFSv2 READDIR, NFSv3 READDIRPLUS, and NFSv4 READDIR implementations,
and it's been like this since the beginning of kernel git history.

I copied the logic from nfsd3_proc_readdirplus().

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfs3proc.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index d9be589fed15..e0ad18d6b5a8 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -430,6 +430,7 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
 	struct nfsd3_readdirargs *argp = rqstp->rq_argp;
 	struct nfsd3_readdirres  *resp = rqstp->rq_resp;
 	int		count = 0;
+	loff_t		offset;
 	struct page	**p;
 	caddr_t		page_addr = NULL;
 
@@ -448,7 +449,9 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
 	resp->common.err = nfs_ok;
 	resp->buffer = argp->buffer;
 	resp->rqstp = rqstp;
-	resp->status = nfsd_readdir(rqstp, &resp->fh, (loff_t *)&argp->cookie,
+	offset = argp->cookie;
+
+	resp->status = nfsd_readdir(rqstp, &resp->fh, &offset,
 				    &resp->common, nfs3svc_encode_entry);
 	memcpy(resp->verf, argp->verf, 8);
 	count = 0;
@@ -464,8 +467,6 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
 	}
 	resp->count = count >> 2;
 	if (resp->offset) {
-		loff_t offset = argp->cookie;
-
 		if (unlikely(resp->offset1)) {
 			/* we ended up with offset on a page boundary */
 			*resp->offset = htonl(offset >> 32);