From patchwork Wed Jun 16 15:49:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Matthew Wilcox (Oracle)" X-Patchwork-Id: 12325549 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=-18.8 required=3.0 tests=BAYES_00,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, USER_AGENT_GIT 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 B0984C48BE6 for ; Wed, 16 Jun 2021 15:50:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8317960FF1 for ; Wed, 16 Jun 2021 15:50:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234724AbhFPPwZ (ORCPT ); Wed, 16 Jun 2021 11:52:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234793AbhFPPwY (ORCPT ); Wed, 16 Jun 2021 11:52:24 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F3EBC061574; Wed, 16 Jun 2021 08:50:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:In-Reply-To:References; bh=E5vX2MLfmqTWkpek062RxTj+YrNTuLmQP4A+jQIoiJ4=; b=dIAWMqFaji5kUvQpp46QKUy+Fh CI4H3SUGQXMsU3C1s3aXacUCPKT9OZeZSNlVyBCfWWzQ6HyJbXbe/P+d6LD5+1Q/m3RWX5zf9tjJo 3fqeoVmCohgUa/G1D4G17YK0F+csk105KUK/6RCyBvwWzB7TGQ6q3O8cO0x3h2G+bZpABCAlRL2xv d/u4UMaEMGOMeRdUDHBjV/ZSgn9CazHVFG1o7VxqynEqaiVlfaNW3UqfvWj4NYL1maffO2NnuGDAM jQbxFtRohDPYjrmlVJtnpIaXm/vUUausGSCbPoPi08mZApH3g2EzkV23SAFfWTZLAULsQgvT6um7a 5UEuEdtw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1ltXmp-008DWU-7P; Wed, 16 Jun 2021 15:49:09 +0000 From: "Matthew Wilcox (Oracle)" To: David Howells , Marc Dionne , linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: "Matthew Wilcox (Oracle)" Subject: [PATCH] afs: Re-enable freezing once a page fault is interrupted Date: Wed, 16 Jun 2021 16:49:00 +0100 Message-Id: <20210616154900.1958373-1-willy@infradead.org> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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. Signed-off-by: Matthew Wilcox (Oracle) --- 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 a523bb86915d..62dd906f9b72 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -832,6 +832,7 @@ int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) */ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) { + vm_fault_t ret = VM_FAULT_RETRY; struct page *page = thp_head(vmf->page); struct file *file = vmf->vma->vm_file; struct inode *inode = file_inode(file); @@ -848,14 +849,14 @@ 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 @@ -863,7 +864,7 @@ 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)); @@ -877,8 +878,10 @@ 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; } /*