From patchwork Fri Oct 7 01:27:49 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 9365561 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6E3D3607D3 for ; Fri, 7 Oct 2016 01:28:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3F29C2929A for ; Fri, 7 Oct 2016 01:28:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2F52B2929C; Fri, 7 Oct 2016 01:28:04 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_TVD_MIME_EPI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6C42F2929A for ; Fri, 7 Oct 2016 01:28:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754781AbcJGB17 (ORCPT ); Thu, 6 Oct 2016 21:27:59 -0400 Received: from mx2.suse.de ([195.135.220.15]:53688 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754374AbcJGB16 (ORCPT ); Thu, 6 Oct 2016 21:27:58 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 91550AD67; Fri, 7 Oct 2016 01:27:56 +0000 (UTC) From: NeilBrown To: Trond Myklebust , Anna Schumaker Date: Fri, 07 Oct 2016 12:27:49 +1100 Cc: NFS List Subject: Re: [PATCH] NFS: Don't disconnect open-owner on NFS4ERR_BAD_SEQID In-Reply-To: <87y46monel.fsf@notabene.neil.brown.name> References: <87y46monel.fsf@notabene.neil.brown.name> User-Agent: Notmuch/0.22.1 (http://notmuchmail.org) Emacs/24.5.1 (x86_64-suse-linux-gnu) Message-ID: <87bmyx3q3u.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Hi again, I posted a version of this patch 4 months and got no reply, so thought it might be time to try again. This version includes a small change to handle the case when a delegation stateid gets a BAD_STATEID, in the context of the open-owner getting a BAD_SEQID. Obviously this whole issue can only happen if the server is buggy (or if the client is buggy, but I don't think it is), but it would be best to handle that case gracefully. Currently it spins indefinitely. Thanks, NeilBrown From: NeilBrown Subject: [PATCH] NFS: Don't disconnect open-owner on NFS4ERR_BAD_SEQID When an NFS4ERR_BAD_SEQID is received the open-owner is removed from the ->state_owners rbtree so that it will no longer be used. If any stateids attached to this open-owner are still in use, and if a request using one get an NFS4ERR_BAD_STATEID reply, this can for bad. The state is marked as needing recovery and the nfs4_state_manager() is scheduled to clean up. nfs4_state_manager() finds states to be recovered by walking the state_owners rbtree. As the open-owner is not in the rbtree, the bad state is not found so nfs4_state_manager() completes having done nothing. The request is then retried, with a predicatable result (indefinite retries). This patch changes NFS4ERR_BAD_SEQID handling to leave the open-owner in the rbtree but mark it a 'stale'. With this the indefinite retries no longer happen. Errors get to user-space instead if recovery doesn't work. If the stateid is for a delegation, the result is more complex. nfs4_state_manager() tries to return the delegation but uses the open-owner with the bad seqid to open files on the server, and this fails with more BAD_SEQID errors. To avoid this we update the so_seqid.create_time of the bad open-owner so that it looks to the server like a new open-owner and an OPEN_CONFIRM is requested. This allows the return of the delagation to complete. Signed-off-by: NeilBrown --- fs/nfs/nfs4_fs.h | 3 ++- fs/nfs/nfs4state.c | 22 +++++++++------------- 2 files changed, 11 insertions(+), 14 deletions(-) diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h index 3f0e459f2499..6be19814553f 100644 --- a/fs/nfs/nfs4_fs.h +++ b/fs/nfs/nfs4_fs.h @@ -113,7 +113,8 @@ struct nfs4_state_owner { enum { NFS_OWNER_RECLAIM_REBOOT, - NFS_OWNER_RECLAIM_NOGRACE + NFS_OWNER_RECLAIM_NOGRACE, + NFS_OWNER_STALE, }; #define NFS_LOCK_NEW 0 diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c index 74cc32490c7a..8ed2285fc527 100644 --- a/fs/nfs/nfs4state.c +++ b/fs/nfs/nfs4state.c @@ -397,6 +397,8 @@ nfs4_find_state_owner_locked(struct nfs_server *server, struct rpc_cred *cred) p = &parent->rb_left; else if (cred > sp->so_cred) p = &parent->rb_right; + else if (test_bit(NFS_OWNER_STALE, &sp->so_flags)) + p = &parent->rb_left; else { if (!list_empty(&sp->so_lru)) list_del_init(&sp->so_lru); @@ -424,6 +426,8 @@ nfs4_insert_state_owner_locked(struct nfs4_state_owner *new) p = &parent->rb_left; else if (new->so_cred > sp->so_cred) p = &parent->rb_right; + else if (test_bit(NFS_OWNER_STALE, &sp->so_flags)) + p = &parent->rb_left; else { if (!list_empty(&sp->so_lru)) list_del_init(&sp->so_lru); @@ -496,19 +500,11 @@ nfs4_alloc_state_owner(struct nfs_server *server, static void nfs4_drop_state_owner(struct nfs4_state_owner *sp) { - struct rb_node *rb_node = &sp->so_server_node; - - if (!RB_EMPTY_NODE(rb_node)) { - struct nfs_server *server = sp->so_server; - struct nfs_client *clp = server->nfs_client; - - spin_lock(&clp->cl_lock); - if (!RB_EMPTY_NODE(rb_node)) { - rb_erase(rb_node, &server->state_owners); - RB_CLEAR_NODE(rb_node); - } - spin_unlock(&clp->cl_lock); - } + set_bit(NFS_OWNER_STALE, &sp->so_flags); + /* Delegation recall might insist on using this open_owner + * so reset it to force a new 'confirm' stage to be initiated. + */ + sp->so_seqid.create_time = ktime_get(); } static void nfs4_free_state_owner(struct nfs4_state_owner *sp)