From: Christoph Hellwig <hch@lst.de>
Date: Fri, 9 Oct 2015 13:03:26 +0000 (+0200)
Subject: nfsd/blocklayout: accept any minlength
X-Git-Tag: v4.2.5~25
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0d6b6d7625050575f3fdc973cc0258ec04c9f401;p=thirdparty%2Fkernel%2Fstable.git

nfsd/blocklayout: accept any minlength

commit 8c3ad9cb7343dc5f61b8cf3cdbe1016c5e7c2c8b upstream.

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.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/nfsd/blocklayout.c b/fs/nfsd/blocklayout.c
index cdefaa331a071..c29d9421bd5e1 100644
--- a/fs/nfsd/blocklayout.c
+++ b/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;