nfsd: Ensure that nfsd_create_setattr commits files to stable storage

Since nfsd_create_setattr strips the mode from the struct iattr, it
is quite possible that it will optimise away the call to nfsd_setattr
altogether.
If this is the case, then we never call commit_metadata() on the
newly created file.

Also ensure that both nfsd_setattr() and nfsd_create_setattr() fail
when the call to commit_metadata fails.
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

fs/nfsd/vfs.c

@@ -463,7 +463,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 	if (size_change)
 		put_write_access(inode);
 	if (!err)
-		commit_metadata(fhp);
+		err = commit_metadata(fhp);
 out:
 	return err;
 }
@@ -1121,7 +1121,8 @@ nfsd_create_setattr(struct svc_rqst *rqstp, struct svc_fh *resfhp,
 		iap->ia_valid &= ~(ATTR_UID|ATTR_GID);
 	if (iap->ia_valid)
 		return nfsd_setattr(rqstp, resfhp, iap, 0, (time_t)0);
-	return 0;
+	/* Callers expect file metadata to be committed here */
+	return commit_metadata(resfhp);
 }
 
 /* HPUX client sometimes creates a file in mode 000, and sets size to 0.
@@ -1253,9 +1254,10 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	err = nfsd_create_setattr(rqstp, resfhp, iap);
 
 	/*
-	 * nfsd_setattr already committed the child.  Transactional filesystems
-	 * had a chance to commit changes for both parent and child
-	 * simultaneously making the following commit_metadata a noop.
+	 * nfsd_create_setattr already committed the child.  Transactional
+	 * filesystems had a chance to commit changes for both parent and
+	 * child * simultaneously making the following commit_metadata a
+	 * noop.
 	 */
 	err2 = nfserrno(commit_metadata(fhp));
 	if (err2)
@@ -1426,7 +1428,8 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp,
 	err = nfsd_create_setattr(rqstp, resfhp, iap);
 
 	/*
-	 * nfsd_setattr already committed the child (and possibly also the parent).
+	 * nfsd_create_setattr already committed the child
+	 * (and possibly also the parent).
 	 */
 	if (!err)
 		err = nfserrno(commit_metadata(fhp));