nfsd/blocklayout: accept any minlength

Recent Linux clients have started to send GETLAYOUT requests with
minlength less than blocksize.

Servers aren't really allowed to impose this kind of restriction on
layouts; see RFC 5661 section 18.43.3 for details.

This has been observed to cause indefinite hangs on fsx runs on some
clients.

Cc: stable@vger.kernel.org
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/blocklayout.c

@@ -56,14 +56,6 @@ nfsd4_block_proc_layoutget(struct inode *inode, const struct svc_fh *fhp,
 	u32 device_generation = 0;
 	int error;
 
-	/*
-	 * We do not attempt to support I/O smaller than the fs block size,
-	 * or not aligned to it.
-	 */
-	if (args->lg_minlength < block_size) {
-		dprintk("pnfsd: I/O too small\n");
-		goto out_layoutunavailable;
-	}
 	if (seg->offset & (block_size - 1)) {
 		dprintk("pnfsd: I/O misaligned\n");
 		goto out_layoutunavailable;