From: Steve Dickson <SteveD@redhat.com>
Date: Fri, 8 Feb 2008 11:11:24 -0500
Subject: [nfs] interoperability problem with AIX clients
Message-id: 47AC7F2C.3080007@RedHat.com
O-Subject: [RHEL5.2] [PATCH] NFSd: interoperability problem with AIX clients
Bugzilla: 426804

There is is an interoperability problem with the
new SECINFO feature that causes ls on AIX client
to always fail. The problem was know when I submitted
the original patch but the fix had not been accepted
in upstream. This is on longer the case, so I am
proposing this patch be include in the 5.2 beta.

Unfortunately we don't have access to a AIX so I
have depended on IBM to do most of the functionality
testing but I have been concentrating regression testing.

For that last few days I've been running a -78 kernel
with this patch included on my desktop and the server
serving my desktop (i.e. my home directory is nfsv4 mounted).

It also turns out Peter Staubach has been "pounding" my
patched server for the last couple of days during is
client testing... either one of us has seen an problems.

The bz is 426804:
https://bugzilla.redhat.com/show_bug.cgi?id=426804

steved.

Acked-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Peter Staubach <staubach@redhat.com>

diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 6a61d75..da5e7d4 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -723,7 +723,7 @@ nfsd4_verify(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_ver
 	status = nfsd4_encode_fattr(current_fh, current_fh->fh_export,
 				    current_fh->fh_dentry, buf,
 				    &count, verify->ve_bmval,
-				    rqstp);
+				    rqstp, 0);
 
 	/* this means that nfsd4_encode_fattr() ran out of space */
 	if (status == nfserr_resource && count == 0)
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 85af6cb..227b9b7 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1420,7 +1420,7 @@ nfsd4_encode_aclname(struct svc_rqst *rqstp, int whotype, uid_t id, int group,
 int
 nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
 		struct dentry *dentry, u32 *buffer, int *countp, u32 *bmval,
-		struct svc_rqst *rqstp)
+		struct svc_rqst *rqstp, int ignore_crossmnt)
 {
 	u32 bmval0 = bmval[0];
 	u32 bmval1 = bmval[1];
@@ -1783,7 +1783,12 @@ out_acl:
 
 		if ((buflen -= 8) < 0)
                 	goto out_resource;
-		if (exp->ex_mnt->mnt_root->d_inode == dentry->d_inode) {
+		/*
+		 * Get parent's attributes if not ignoring crossmount
+		 * and this is the root of a cross-mounted filesystem.
+		 */
+		if (ignore_crossmnt == 0 &&
+			exp->ex_mnt->mnt_root->d_inode == dentry->d_inode) {
 			status = vfs_getattr(exp->ex_mnt->mnt_parent,
 					exp->ex_mnt->mnt_mountpoint, &stat);
 			if (status)
@@ -1819,13 +1824,25 @@ nfsd4_encode_dirent_fattr(struct nfsd4_readdir *cd,
 	struct svc_export *exp = cd->rd_fhp->fh_export;
 	struct dentry *dentry;
 	int nfserr;
+	int ignore_crossmnt = 0;
 
 	dentry = lookup_one_len(name, cd->rd_fhp->fh_dentry, namlen);
 	if (IS_ERR(dentry))
 		return nfserrno(PTR_ERR(dentry));
 
 	exp_get(exp);
-	if (d_mountpoint(dentry)) {
+	/*
+	 * In the case of a mountpoint, the client may be asking for
+	 * attributes that are only properties of the underlying filesystem
+	 * as opposed to the cross-mounted file system. In such a case,
+	 * we will not follow the cross mount and will fill the attribtutes
+	 * directly from the mountpoint dentry.
+	 */
+	if (d_mountpoint(dentry) && 
+		(cd->rd_bmval[0] & ~FATTR4_WORD0_RDATTR_ERROR) == 0 &&
+		(cd->rd_bmval[1] & ~FATTR4_WORD1_MOUNTED_ON_FILEID) == 0)
+		ignore_crossmnt = 1;
+	else if (d_mountpoint(dentry)) {
   		int err;
   
 		/*
@@ -1843,7 +1860,7 @@ nfsd4_encode_dirent_fattr(struct nfsd4_readdir *cd,
 			goto out_put;
 	}
 	nfserr = nfsd4_encode_fattr(NULL, exp, dentry, p, buflen, cd->rd_bmval,
-					cd->rd_rqstp);
+					cd->rd_rqstp, ignore_crossmnt);
 out_put:
 	dput(dentry);
 	exp_put(exp);
@@ -1996,7 +2013,7 @@ nfsd4_encode_getattr(struct nfsd4_compoundres *resp, int nfserr, struct nfsd4_ge
 	buflen = resp->end - resp->p - (COMPOUND_ERR_SLACK_SPACE >> 2);
 	nfserr = nfsd4_encode_fattr(fhp, fhp->fh_export, fhp->fh_dentry,
 				    resp->p, &buflen, getattr->ga_bmval,
-				    resp->rqstp);
+				    resp->rqstp, 0);
 
 	if (!nfserr)
 		resp->p += buflen;
diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h
index f6ea18f..f894f04 100644
--- a/include/linux/nfsd/xdr4.h
+++ b/include/linux/nfsd/xdr4.h
@@ -437,7 +437,7 @@ void nfsd4_encode_operation(struct nfsd4_compoundres *, struct nfsd4_op *);
 void nfsd4_encode_replay(struct nfsd4_compoundres *resp, struct nfsd4_op *op);
 int nfsd4_encode_fattr(struct svc_fh *fhp, struct svc_export *exp,
 		       struct dentry *dentry, u32 *buffer, int *countp, 
-		       u32 *bmval, struct svc_rqst *);
+		       u32 *bmval, struct svc_rqst *, int ignore_crossmnt);
 extern int nfsd4_setclientid(struct svc_rqst *rqstp, 
 		struct nfsd4_setclientid *setclid);
 extern int nfsd4_setclientid_confirm(struct svc_rqst *rqstp,