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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 F01C7C43461 for ; Tue, 13 Apr 2021 11:29:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D0B2B61370 for ; Tue, 13 Apr 2021 11:29:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238304AbhDML33 (ORCPT ); Tue, 13 Apr 2021 07:29:29 -0400 Received: from mx2.suse.de ([195.135.220.15]:55014 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231346AbhDML3X (ORCPT ); Tue, 13 Apr 2021 07:29:23 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 570B4B167; Tue, 13 Apr 2021 11:29:00 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id E1F7C1F2B6E; Tue, 13 Apr 2021 13:28:59 +0200 (CEST) From: Jan Kara To: Cc: , , Ted Tso , Christoph Hellwig , Amir Goldstein , Dave Chinner , Jan Kara Subject: [PATCH 7/7] fs: Remove i_mapping_sem protection from .page_mkwrite handlers Date: Tue, 13 Apr 2021 13:28:51 +0200 Message-Id: <20210413112859.32249-7-jack@suse.cz> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210413105205.3093-1-jack@suse.cz> References: <20210413105205.3093-1-jack@suse.cz> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Using i_mapping_sem in .page_mkwrite handlers is generally unnecessary since these handlers do not create any new pages in the page cache. Thus if the handler locks the page and it is still attached to appropriate mapping, we are certain there cannot be truncate or hole punch in progress past its page cache invalidation step (remember that a page cannot be created in the page cache from the moment hole punch acquires i_mapping_sem and starts invalidating page cache to the moment the operation is finished and i_mapping_sem is released) and any page cache invalidation will wait until we release the page lock. So just remove i_mapping_sem usage from .page_mkwrite handlers. Signed-off-by: Jan Kara --- fs/ext4/inode.c | 3 --- fs/xfs/xfs_file.c | 2 -- fs/zonefs/super.c | 3 --- 3 files changed, 8 deletions(-) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index d76803eba884..4779b6084a30 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -6064,8 +6064,6 @@ vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) sb_start_pagefault(inode->i_sb); file_update_time(vma->vm_file); - down_read(&inode->i_mapping_sem); - err = ext4_convert_inline_data(inode); if (err) goto out_ret; @@ -6177,7 +6175,6 @@ vm_fault_t ext4_page_mkwrite(struct vm_fault *vmf) out_ret: ret = block_page_mkwrite_return(err); out: - up_read(&inode->i_mapping_sem); sb_end_pagefault(inode->i_sb); return ret; out_error: diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c index a76404708312..416a5c8ccdda 100644 --- a/fs/xfs/xfs_file.c +++ b/fs/xfs/xfs_file.c @@ -1316,10 +1316,8 @@ __xfs_filemap_fault( xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); } else { if (write_fault) { - xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED); ret = iomap_page_mkwrite(vmf, &xfs_buffered_write_iomap_ops); - xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED); } else ret = filemap_fault(vmf); } diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c index ace6f3a223da..a90ef0f09a9f 100644 --- a/fs/zonefs/super.c +++ b/fs/zonefs/super.c @@ -594,10 +594,7 @@ static vm_fault_t zonefs_filemap_page_mkwrite(struct vm_fault *vmf) sb_start_pagefault(inode->i_sb); file_update_time(vmf->vma->vm_file); - /* Serialize against truncates */ - down_read(&inode->i_mapping_sem); ret = iomap_page_mkwrite(vmf, &zonefs_iomap_ops); - up_read(&inode->i_mapping_sem); sb_end_pagefault(inode->i_sb); return ret; -- 2.31.0.99.g0d91da736d9f.dirty