Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:55968 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757371AbaAIVdg (ORCPT ); Thu, 9 Jan 2014 16:33:36 -0500 Date: Thu, 9 Jan 2014 16:33:35 -0500 To: linux-nfs@vger.kernel.org Cc: sandeen@redhat.com, jlayton@redhat.com Subject: fix encode_entryplus_baggage stack usage Message-ID: <20140109213335.GA21559@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii From: "J. Bruce Fields" Sender: linux-nfs-owner@vger.kernel.org List-ID: Eric ran across an excessive stack with this (and a bunch of xfs code) to blame. Untested. I don't know whether it's worth the minor extra work here to avoid the alloc/free on each entry. nfsd4_encode_fattr will need the same treatment. --b. commit 5b35a1f99f999555e82420e687e9d079ae796547 Author: J. Bruce Fields Date: Thu Jan 9 16:24:35 2014 -0500 nfsd: fix encode_entryplus_baggage stack usage We stick an extra svc_fh in nfsd3_readdirres to save the need to kmalloc, though maybe it would be fine to kmalloc instead. Signed-off-by: J. Bruce Fields diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c index 1ee6bae..de6e39e 100644 --- a/fs/nfsd/nfs3xdr.c +++ b/fs/nfsd/nfs3xdr.c @@ -842,21 +842,21 @@ out: static __be32 *encode_entryplus_baggage(struct nfsd3_readdirres *cd, __be32 *p, const char *name, int namlen) { - struct svc_fh fh; + struct svc_fh *fh = &cd->scratch; __be32 err; - fh_init(&fh, NFS3_FHSIZE); - err = compose_entry_fh(cd, &fh, name, namlen); + fh_init(fh, NFS3_FHSIZE); + err = compose_entry_fh(cd, fh, name, namlen); if (err) { *p++ = 0; *p++ = 0; goto out; } - p = encode_post_op_attr(cd->rqstp, p, &fh); + p = encode_post_op_attr(cd->rqstp, p, fh); *p++ = xdr_one; /* yes, a file handle follows */ - p = encode_fh(p, &fh); + p = encode_fh(p, fh); out: - fh_put(&fh); + fh_put(fh); return p; } diff --git a/fs/nfsd/xdr3.h b/fs/nfsd/xdr3.h index b6d5542..335e04a 100644 --- a/fs/nfsd/xdr3.h +++ b/fs/nfsd/xdr3.h @@ -174,6 +174,9 @@ struct nfsd3_linkres { struct nfsd3_readdirres { __be32 status; struct svc_fh fh; + /* Just to save kmalloc on every readdirplus entry (svc_fh is a + * little large for the stack): */ + struct svc_fh scratch; int count; __be32 verf[2];