From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53016 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S939513AbdAFVwx (ORCPT ); Fri, 6 Jan 2017 16:52:53 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Trond Myklebust Subject: [PATCH 4.8 83/96] pNFS: Fix a deadlock between read resends and layoutreturn Date: Fri, 6 Jan 2017 22:44:11 +0100 Message-Id: <20170106214231.095036751@linuxfoundation.org> In-Reply-To: <20170106214227.601120243@linuxfoundation.org> References: <20170106214227.601120243@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Trond Myklebust commit 54e4a0dfa25d9365c4e80a639e80d9213eb6edbe upstream. We must not call nfs_pageio_init_read() on a new nfs_pageio_descriptor while holding a reference to a layout segment, as that can deadlock pnfs_update_layout(). Fixes: d67ae825a59d6 ("pnfs/flexfiles: Add the FlexFile Layout Driver") Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman --- fs/nfs/flexfilelayout/flexfilelayout.c | 4 ++++ fs/nfs/pnfs.c | 4 ++++ 2 files changed, 8 insertions(+) --- a/fs/nfs/flexfilelayout/flexfilelayout.c +++ b/fs/nfs/flexfilelayout/flexfilelayout.c @@ -28,6 +28,9 @@ static struct group_info *ff_zero_group; +static void ff_layout_read_record_layoutstats_done(struct rpc_task *task, + struct nfs_pgio_header *hdr); + static struct pnfs_layout_hdr * ff_layout_alloc_layout_hdr(struct inode *inode, gfp_t gfp_flags) { @@ -1293,6 +1296,7 @@ static int ff_layout_read_done_cb(struct hdr->pgio_mirror_idx + 1, &hdr->pgio_mirror_idx)) goto out_eagain; + ff_layout_read_record_layoutstats_done(task, hdr); pnfs_read_resend_pnfs(hdr); return task->tk_status; case -NFS4ERR_RESET_TO_MDS: --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -2248,6 +2248,10 @@ void pnfs_read_resend_pnfs(struct nfs_pg struct nfs_pageio_descriptor pgio; if (!test_and_set_bit(NFS_IOHDR_REDO, &hdr->flags)) { + /* Prevent deadlocks with layoutreturn! */ + pnfs_put_lseg(hdr->lseg); + hdr->lseg = NULL; + nfs_pageio_init_read(&pgio, hdr->inode, false, hdr->completion_ops); hdr->task.tk_status = nfs_pageio_resend(&pgio, hdr);