nfsd4: break only delegations when appropriate

As a temporary fix, nfsd was breaking all leases on unlink, link,
rename, and setattr.

Now that we can distinguish between leases and delegations, we can be
nicer and break only the delegations, and not bother lease-holders with
operations they don't care about.

And we get to delete some code while we're at it.

Note that in the presence of delegations the vfs calls here all return
-EWOULDBLOCK instead of blocking, so nfsd threads will not get stuck
waiting for delegation returns.
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/vfs.c

@@ -273,13 +273,6 @@ nfsd_lookup(struct svc_rqst *rqstp, struct svc_fh *fhp, const char *name,
 	return err;
 }
 
-static int nfsd_break_lease(struct inode *inode)
-{
-	if (!S_ISREG(inode->i_mode))
-		return 0;
-	return break_lease(inode, O_WRONLY | O_NONBLOCK);
-}
-
 /*
  * Commit metadata changes to stable storage.
  */
@@ -448,16 +441,10 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap,
 		goto out_put_write_access;
 	}
 
-	host_err = nfsd_break_lease(inode);
-	if (host_err)
-		goto out_put_write_access_nfserror;
-
 	fh_lock(fhp);
 	host_err = notify_change(dentry, iap, NULL);
 	fh_unlock(fhp);
 
-out_put_write_access_nfserror:
-	err = nfserrno(host_err);
 out_put_write_access:
 	if (size_change)
 		put_write_access(inode);
@@ -1759,11 +1746,6 @@ nfsd_link(struct svc_rqst *rqstp, struct svc_fh *ffhp,
 	err = nfserr_noent;
 	if (!dold->d_inode)
 		goto out_dput;
-	host_err = nfsd_break_lease(dold->d_inode);
-	if (host_err) {
-		err = nfserrno(host_err);
-		goto out_dput;
-	}
 	host_err = vfs_link(dold, dirp, dnew, NULL);
 	if (!host_err) {
 		err = nfserrno(commit_metadata(ffhp));
@@ -1857,14 +1839,6 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen,
 	if (ffhp->fh_export->ex_path.dentry != tfhp->fh_export->ex_path.dentry)
 		goto out_dput_new;
 
-	host_err = nfsd_break_lease(odentry->d_inode);
-	if (host_err)
-		goto out_dput_new;
-	if (ndentry->d_inode) {
-		host_err = nfsd_break_lease(ndentry->d_inode);
-		if (host_err)
-			goto out_dput_new;
-	}
 	host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL);
 	if (!host_err) {
 		host_err = commit_metadata(tfhp);
@@ -1934,16 +1908,12 @@ nfsd_unlink(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
 	if (!type)
 		type = rdentry->d_inode->i_mode & S_IFMT;
 
-	host_err = nfsd_break_lease(rdentry->d_inode);
-	if (host_err)
-		goto out_put;
 	if (type != S_IFDIR)
 		host_err = vfs_unlink(dirp, rdentry, NULL);
 	else
 		host_err = vfs_rmdir(dirp, rdentry);
 	if (!host_err)
 		host_err = commit_metadata(fhp);
-out_put:
 	dput(rdentry);
 
 out_nfserr: