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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 7F3DAC4360C for ; Tue, 8 Oct 2019 07:15:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52EBE2173B for ; Tue, 8 Oct 2019 07:15:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="gqM2lNpZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730242AbfJHHPr (ORCPT ); Tue, 8 Oct 2019 03:15:47 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:53474 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730150AbfJHHPr (ORCPT ); Tue, 8 Oct 2019 03:15:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:To:From:Sender: Reply-To:Cc:Content-Type:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=2Jwee5q8LQz4jhFGIfaJLAkC3AxGj7sm6QFBKI+1xL8=; b=gqM2lNpZO8M9uXNqcZXW/FsSK g9lai7Sp5mrM/RDHHCMqSSMfTJUL7BjhxTtNOPhH2soPxzCAs4r/5b694dHtwwK0aKnbuRwoT/q0x Fb/L7x6DoWPsbUUY4WLIMrBDkbBgwmILVLYr+U3lGvriJEp8KukB21mzR29buGybA5F0OAgg9g5e4 nXhjtxWM+u0ZvrBpcjPuSd7jtcl85zi0nq/WHeGG8w4QLnQO//uty2xFgze+oZkouHjMRPLq2ZGaB WzLTlj/VJluVxZYigv7fa4S6Lzx/fU5HiW3MtAwgEjc460EVRNjl0xsprDjABJneC2dj7dbosTqHg T8D+MX5LQ==; Received: from [2001:4bb8:188:141c:c70:4a89:bc61:2] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.2 #3 (Red Hat Linux)) id 1iHjik-0005x4-Rm; Tue, 08 Oct 2019 07:15:47 +0000 From: Christoph Hellwig To: Goldwyn Rodrigues , linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 06/20] iomap: use write_begin to read pages to unshare Date: Tue, 8 Oct 2019 09:15:13 +0200 Message-Id: <20191008071527.29304-7-hch@lst.de> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191008071527.29304-1-hch@lst.de> References: <20191008071527.29304-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org Use the existing iomap write_begin code to read the pages unshared by iomap_file_unshare. That avoids the extra ->readpage call and extent tree lookup currently done by read_mapping_page. Signed-off-by: Christoph Hellwig --- fs/iomap/buffered-io.c | 49 ++++++++++++++---------------------------- 1 file changed, 16 insertions(+), 33 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index d5abd8e5dca7..ac1bbed71a9b 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -548,6 +548,10 @@ iomap_migrate_page(struct address_space *mapping, struct page *newpage, EXPORT_SYMBOL_GPL(iomap_migrate_page); #endif /* CONFIG_MIGRATION */ +enum { + IOMAP_WRITE_F_UNSHARE = (1 << 0), +}; + static void iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) { @@ -577,7 +581,7 @@ iomap_read_page_sync(loff_t block_start, struct page *page, unsigned poff, } static int -__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, +__iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, struct page *page, struct iomap *iomap) { struct iomap_page *iop = iomap_page_create(inode, page); @@ -596,11 +600,14 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, if (plen == 0) break; - if ((from <= poff || from >= poff + plen) && + if (!(flags & IOMAP_WRITE_F_UNSHARE) && + (from <= poff || from >= poff + plen) && (to <= poff || to >= poff + plen)) continue; if (iomap_block_needs_zeroing(inode, iomap, block_start)) { + if (WARN_ON_ONCE(flags & IOMAP_WRITE_F_UNSHARE)) + return -EIO; zero_user_segments(page, poff, from, to, poff + plen); iomap_set_range_uptodate(page, poff, plen); continue; @@ -646,7 +653,8 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, else if (iomap->flags & IOMAP_F_BUFFER_HEAD) status = __block_write_begin_int(page, pos, len, NULL, iomap); else - status = __iomap_write_begin(inode, pos, len, page, iomap); + status = __iomap_write_begin(inode, pos, len, flags, page, + iomap); if (unlikely(status)) goto out_unlock; @@ -869,22 +877,6 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter, } EXPORT_SYMBOL_GPL(iomap_file_buffered_write); -static struct page * -__iomap_read_page(struct inode *inode, loff_t offset) -{ - struct address_space *mapping = inode->i_mapping; - struct page *page; - - page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL); - if (IS_ERR(page)) - return page; - if (!PageUptodate(page)) { - put_page(page); - return ERR_PTR(-EIO); - } - return page; -} - static loff_t iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) @@ -900,24 +892,15 @@ iomap_unshare_actor(struct inode *inode, loff_t pos, loff_t length, void *data, return length; do { - struct page *page, *rpage; - unsigned long offset; /* Offset into pagecache page */ - unsigned long bytes; /* Bytes to write to page */ - - offset = offset_in_page(pos); - bytes = min_t(loff_t, PAGE_SIZE - offset, length); - - rpage = __iomap_read_page(inode, pos); - if (IS_ERR(rpage)) - return PTR_ERR(rpage); + unsigned long offset = offset_in_page(pos); + unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length); + struct page *page; - status = iomap_write_begin(inode, pos, bytes, 0, &page, iomap); - put_page(rpage); + status = iomap_write_begin(inode, pos, bytes, + IOMAP_WRITE_F_UNSHARE, &page, iomap); if (unlikely(status)) return status; - WARN_ON_ONCE(!PageUptodate(page)); - status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); if (unlikely(status <= 0)) { if (WARN_ON_ONCE(status == 0)) -- 2.20.1