From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1511654-1518326043-2-3264863811027786052 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='uk', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1518326042; b=Zq3iSMYSAnBexFKGfYa/s5T6vHeneXwbJCoI6BOHyFhdIxi hlcoyXEB7ZuVOiPBFz2mJaUJb60UDFJWSjoI0MfpXCmnDmopEIEqbD9+364XFBka R5K9tuzDYq9KXjbXSIa6Xs6T6T9TnkrgJRLDQHBQwZX6oSRLrvR8gpnVyoefCF86 wxDM7lJYNoa7mjrJ+Bipwu86fMY0rxjf3h0+SVn+3OLh91Wbyub8N4eA8Necf3rM zaCN9isPi13xZ7Jb7todgi8ptjZRniCHLfD8XkAgUI87/I8Y8YiAKXyx412vzGn1 JuUiK2+q3Wp1Ou6VpVYcMt8DAUKRgoAuEH+wA8Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1518326042; bh=y0mZqfPUiAZ+upshjlp NiQr3t3cARq973qsUUedzfFI=; b=g60XhMyuVFBJjfYlnUGJBRSEFeQ/TJF2slD mjKBj/xp3SldvWDgALn2uaW5TA0pyyhFOK9/FmFshM1Gy1JMv+OQx088l6IN6yl8 H9XH3qV1t4Zan85rei1k1F6gQddPYFSlU8ep6igVvBY0/nJlc1DxgK3+etDe4L6I X5ofK+MVjCx3JJ3MzCe5PvtOaQXt4oS+4C78kli0+/VmZzt1KH/xESChtl2HomGl 6Pg7+8WeOeyhN2ZpUisBS3rtVFArgehIdpGcZDcO4rvGRmBRcIRtbH/ekmqoNnEo zvHsI7FtBG1szcQpGMgsvCKfFH1f+fcZw1lo7esDk/E8q6C6BZw== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753672AbeBKFMZ (ORCPT ); Sun, 11 Feb 2018 00:12:25 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41404 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752623AbeBKEdl (ORCPT ); Sat, 10 Feb 2018 23:33:41 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "NeilBrown" , "Ian Kent" , "Linus Torvalds" Date: Sun, 11 Feb 2018 04:20:06 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 51/79] autofs: don't fail mount for transient error In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.2.99-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: NeilBrown commit ecc0c469f27765ed1e2b967be0aa17cee1a60b76 upstream. Currently if the autofs kernel module gets an error when writing to the pipe which links to the daemon, then it marks the whole moutpoint as catatonic, and it will stop working. It is possible that the error is transient. This can happen if the daemon is slow and more than 16 requests queue up. If a subsequent process tries to queue a request, and is then signalled, the write to the pipe will return -ERESTARTSYS and autofs will take that as total failure. So change the code to assess -ERESTARTSYS and -ENOMEM as transient failures which only abort the current request, not the whole mountpoint. It isn't a crash or a data corruption, but having autofs mountpoints suddenly stop working is rather inconvenient. Ian said: : And given the problems with a half dozen (or so) user space applications : consuming large amounts of CPU under heavy mount and umount activity this : could happen more easily than we expect. Link: http://lkml.kernel.org/r/87y3norvgp.fsf@notabene.neil.brown.name Signed-off-by: NeilBrown Acked-by: Ian Kent Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds [bwh: Backported to 3.2: autofs4_write() doesn't take an autofs_sb_info pointer] Signed-off-by: Ben Hutchings --- fs/autofs4/waitq.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) --- a/fs/autofs4/waitq.c +++ b/fs/autofs4/waitq.c @@ -88,7 +88,8 @@ static int autofs4_write(struct file *fi spin_unlock_irqrestore(¤t->sighand->siglock, flags); } - return (bytes > 0); + /* if 'wr' returned 0 (impossible) we assume -EIO (safe) */ + return bytes == 0 ? 0 : wr < 0 ? wr : -EIO; } static void autofs4_notify_daemon(struct autofs_sb_info *sbi, @@ -102,6 +103,7 @@ static void autofs4_notify_daemon(struct } pkt; struct file *pipe = NULL; size_t pktsz; + int ret; DPRINTK("wait id = 0x%08lx, name = %.*s, type=%d", (unsigned long) wq->wait_queue_token, wq->name.len, wq->name.name, type); @@ -180,7 +182,18 @@ static void autofs4_notify_daemon(struct mutex_unlock(&sbi->wq_mutex); if (autofs4_write(pipe, &pkt, pktsz)) + switch (ret = autofs4_write(pipe, &pkt, pktsz)) { + case 0: + break; + case -ENOMEM: + case -ERESTARTSYS: + /* Just fail this one */ + autofs4_wait_release(sbi, wq->wait_queue_token, ret); + break; + default: autofs4_catatonic_mode(sbi); + break; + } fput(pipe); }