From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04A10C48BE5 for ; Wed, 16 Jun 2021 21:22:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB1F361351 for ; Wed, 16 Jun 2021 21:22:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233987AbhFPVYm (ORCPT ); Wed, 16 Jun 2021 17:24:42 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:48414 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233909AbhFPVYl (ORCPT ); Wed, 16 Jun 2021 17:24:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1623878553; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=GUzVV1RzuS/uejV8gOCi1Hq++h3D2eM6DMUllFfeIsg=; b=Am9PY8HLr42aDk+GutZ8JmawblxL//m9QFtZR5elHnJ90dOK1mn+EZj2LoP+Ran5Q5zv/m ikFwuFe+dpib3NC46k5xxVySzcM72vl+nPyPhHAZ14o2SBI/9pUeTlRhV0nx7lE+cQAPUG WPMLEea22YNlnxgEp8nywpEX69r1VVE= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-274-sqaPo7RxOm-kKy-LjM7vgw-1; Wed, 16 Jun 2021 17:22:32 -0400 X-MC-Unique: sqaPo7RxOm-kKy-LjM7vgw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2A48D18D6A2C; Wed, 16 Jun 2021 21:22:31 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-118-65.rdu2.redhat.com [10.10.118.65]) by smtp.corp.redhat.com (Postfix) with ESMTP id DB5C55C1D0; Wed, 16 Jun 2021 21:22:29 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH] afs: Re-enable freezing once a page fault is interrupted From: David Howells To: torvalds@linux-foundation.org Cc: "Matthew Wilcox (Oracle)" , linux-afs@lists.infradead.org, dhowells@redhat.com, marc.dionne@auristor.com, linux-afs@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 16 Jun 2021 22:22:28 +0100 Message-ID: <162387854886.1035841.15139736369962171742.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.23 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Matthew Wilcox (Oracle) If a task is killed during a page fault, it does not currently call sb_end_pagefault(), which means that the filesystem cannot be frozen at any time thereafter. This may be reported by lockdep like this: ==================================== WARNING: fsstress/10757 still has locks held! 5.13.0-rc4-build4+ #91 Not tainted ------------------------------------ 1 lock held by fsstress/10757: #0: ffff888104eac530 ( sb_pagefaults as filesystem freezing is modelled as a lock. Fix this by removing all the direct returns from within the function, and using 'ret' to indicate whether we were interrupted or successful. Fixes: 1cf7a1518aef ("afs: Implement shared-writeable mmap") Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: David Howells cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/20210616154900.1958373-1-willy@infradead.org/ --- fs/afs/write.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/fs/afs/write.c b/fs/afs/write.c index f722cb80a594..ff36800a7389 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -848,6 +848,7 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) struct inode *inode = file_inode(file); struct afs_vnode *vnode = AFS_FS_I(inode); unsigned long priv; + vm_fault_t ret = VM_FAULT_RETRY; _enter("{{%llx:%llu}},{%lx}", vnode->fid.vid, vnode->fid.vnode, page->index); @@ -859,14 +860,14 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) #ifdef CONFIG_AFS_FSCACHE if (PageFsCache(page) && wait_on_page_fscache_killable(page) < 0) - return VM_FAULT_RETRY; + goto out; #endif if (wait_on_page_writeback_killable(page)) - return VM_FAULT_RETRY; + goto out; if (lock_page_killable(page) < 0) - return VM_FAULT_RETRY; + goto out; /* We mustn't change page->private until writeback is complete as that * details the portion of the page we need to write back and we might @@ -874,7 +875,7 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) */ if (wait_on_page_writeback_killable(page) < 0) { unlock_page(page); - return VM_FAULT_RETRY; + goto out; } priv = afs_page_dirty(page, 0, thp_size(page)); @@ -888,8 +889,10 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) } file_update_time(file); + ret = VM_FAULT_LOCKED; +out: sb_end_pagefault(inode->i_sb); - return VM_FAULT_LOCKED; + return ret; } /*