From: Brad Peters <bpeters@redhat.com>
Date: Wed, 5 Mar 2008 17:24:03 -0500
Subject: [nfs] fslocations/referrals broken
Message-id: 20080305222403.GE8084@bpeters-ibm
O-Subject: Re: [RHEL-5.2 PATCH] BZ#432690 - [regression] NFS fslocations/referrals broken
Bugzilla: 432690

RHBZ#:
------------
https://bugzilla.redhat.com/show_bug.cgi?id=432690

Description:
------------
The NFS Security Negotiation feature (RHBZ253019: LTC37709: 200628: NFS
Security
Negotiation) introduced two regressions in 2.6.18-78.el5.  This bug fixes
those problems.

The first issue is a serious regression that totally breaks nfs referrals
(fs
locations). It is fixed by removing a redundant parsing of the export
stream for
the fsloc option.

The second issue is a regression that causes a directory entry which is a
mount
point for a sub-mounted file system to appear incorrectly.

The second segment is upstream here:

http://git.kernel.org/
?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=a1033be72cdb053e1
82bb41e302a1c11e72b68bb

The first segment fixes a problem that arose from a bad backport/merge of
the
security negotiation code into RHEL 5.1 (this code segment moved - which
caused
it to appear twice in the backport)

NFS fslocations/referrals regressed and is completely unuseable, this
function
worked in 5.1.

The patch was tested and addresses the problem - I have run my security
negotiation test suite against it from both Linux and AIX clients. The
suite includes referral testing.

RHEL Version Found:
------------
Regression - fix for feature added in 5.1

kABI Status:
------------
No symbols were harmed.

Upstream Status:
------------
The second part of this patch is upstream in git commit:
a1033be72cdb053e182bb41e302a1c11e72b68bb

Test Status:
------------
Verified to fix referrals and negotiation on a system-X system
---------------------------------------------------------------

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index b72402b..d6bd71a 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -409,10 +409,6 @@ fsloc_parse(char **mesg, char *buf, struct nfsd4_fs_locations *fsloc)
 	int len;
 	int migrated, i, err;
 
-	len = qword_get(mesg, buf, PAGE_SIZE);
-	if (len != 5 || memcmp(buf, "fsloc", 5))
-		return 0;
-
 	/* listsize */
 	err = get_int(mesg, &fsloc->locations_count);
 	if (err)
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 31e2e7f..ebd8bf6 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -106,7 +106,8 @@ nfsd_cross_mnt(struct svc_rqst *rqstp, struct dentry **dpp,
 
 	exp2 = rqst_exp_get_by_name(rqstp, mnt, mounts);
 	if (IS_ERR(exp2)) {
-		err = PTR_ERR(exp2);
+		if (PTR_ERR(exp2) != -ENOENT)
+			err = PTR_ERR(exp2);
 		dput(mounts);
 		mntput(mnt);
 		goto out;