linux-kernel - [PATCH] nfsd: allow nfsv3 readdir request to be larger.

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Message-ID: <87y35rr52t.fsf@notabene.neil.brown.name>
Date:   Thu, 07 Mar 2019 09:49:46 +1100
From:   NeilBrown <neilb@...e.com>
To:     "J. Bruce Fields" <bfields@...ldses.org>
Cc:     Jeff Layton <jlayton@...nel.org>, linux-nfs@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] nfsd: allow nfsv3 readdir request to be larger.


nfsd currently reports the NFSv4 dtpref FSINFO parameter
to be PAGE_SIZE, so NFS clients will typically ask for one
page of directory entries at a time.  This is needlessly restrictive
as nfsd can handle larger replies easily.

Also, a READDIR request (but not a READDIRPLUS request) has the count
size clipped to PAGE_SIE, again unnecessary.

This patch lifts these limits so that larger readdir requests can be
used.

Signed-off-by: NeilBrown <neilb@...e.com>
---
 fs/nfsd/nfs3proc.c | 2 +-
 fs/nfsd/nfs3xdr.c  | 4 +++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
index c9cf46e0c040..8f933e84cec1 100644
--- a/fs/nfsd/nfs3proc.c
+++ b/fs/nfsd/nfs3proc.c
@@ -588,7 +588,7 @@ nfsd3_proc_fsinfo(struct svc_rqst *rqstp)
 	resp->f_wtmax  = max_blocksize;
 	resp->f_wtpref = max_blocksize;
 	resp->f_wtmult = PAGE_SIZE;
-	resp->f_dtpref = PAGE_SIZE;
+	resp->f_dtpref = max_blocksize;
 	resp->f_maxfilesize = ~(u32) 0;
 	resp->f_properties = NFS3_FSF_DEFAULT;
 
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
index 83919116d5cb..93fea246f676 100644
--- a/fs/nfsd/nfs3xdr.c
+++ b/fs/nfsd/nfs3xdr.c
@@ -573,6 +573,8 @@ int
 nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
 {
 	struct nfsd3_readdirargs *args = rqstp->rq_argp;
+	u32 max_blocksize = svc_max_payload(rqstp);
+
 	p = decode_fh(p, &args->fh);
 	if (!p)
 		return 0;
@@ -580,7 +582,7 @@ nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
 	args->verf   = p; p += 2;
 	args->dircount = ~0;
 	args->count  = ntohl(*p++);
-	args->count  = min_t(u32, args->count, PAGE_SIZE);
+	args->count  = min_t(u32, args->count, max_blocksize);
 	args->buffer = page_address(*(rqstp->rq_next_page++));
 
 	return xdr_argsize_check(rqstp, p);
-- 
2.14.0.rc0.dirty


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