Return-Path: linux-nfs-owner@vger.kernel.org Received: from casper.infradead.org ([85.118.1.10]:45760 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753145AbaHGHVb (ORCPT ); Thu, 7 Aug 2014 03:21:31 -0400 From: Christoph Hellwig To: Trond Myklebust Cc: linux-nfs@vger.kernel.org Subject: [PATCH 01/17] nfs: cap request size to fit a kmalloced page array Date: Thu, 7 Aug 2014 09:23:33 +0200 Message-Id: <1407396229-4785-2-git-send-email-hch@lst.de> In-Reply-To: <1407396229-4785-1-git-send-email-hch@lst.de> References: <1407396229-4785-1-git-send-email-hch@lst.de> Sender: linux-nfs-owner@vger.kernel.org List-ID: pNFS servers may return arbitrarily large layouts. Trim back the I/O size to one that we can at least allocate the page array for. Signed-off-by: Christoph Hellwig --- fs/nfs/pagelist.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 9425118..23471b1 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -466,6 +466,14 @@ size_t nfs_generic_pg_test(struct nfs_pageio_descriptor *desc, return 0; } + /* + * Limit the request size so that we can still allocate a page array + * for it without upsetting the slab allocator. + */ + if (((desc->pg_count + req->wb_bytes) >> PAGE_SHIFT) * + sizeof(struct page) > PAGE_SIZE) + return 0; + return min(desc->pg_bsize - desc->pg_count, (size_t)req->wb_bytes); } EXPORT_SYMBOL_GPL(nfs_generic_pg_test); -- 1.9.1