nfsd: fh_drop_write in nfsd_unlink

fh_want_write() can now be called twice, but I'm also fixing up the
callers not to do that.

Other cases include setattr and create.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/vfs.c

@@ -1786,12 +1786,12 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 	rdentry = lookup_one_len(fname, dentry, flen);
 	host_err = PTR_ERR(rdentry);
 	if (IS_ERR(rdentry))
-		goto out_nfserr;
+		goto out_drop_write;
 
 	if (d_really_is_negative(rdentry)) {
 		dput(rdentry);
-		err = nfserr_noent;
-		goto out;
+		host_err = -ENOENT;
+		goto out_drop_write;
 	}
 
 	if (!type)
@@ -1805,6 +1805,8 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 		host_err = commit_metadata(fhp);
 	dput(rdentry);
 
+out_drop_write:
+	fh_drop_write(fhp);
 out_nfserr:
 	err = nfserrno(host_err);
 out: