From patchwork Fri May 18 16:48:11 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 10411289 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7F444601F9 for ; Fri, 18 May 2018 16:49:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6FE8828619 for ; Fri, 18 May 2018 16:49:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 64DCB288BD; Fri, 18 May 2018 16:49:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE, T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C61A128894 for ; Fri, 18 May 2018 16:49:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6E39F6B0613; Fri, 18 May 2018 12:49:19 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 66CC06B0614; Fri, 18 May 2018 12:49:19 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4C1A26B0615; Fri, 18 May 2018 12:49:19 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id 047176B0613 for ; Fri, 18 May 2018 12:49:19 -0400 (EDT) Received: by mail-pl0-f70.google.com with SMTP id f35-v6so5355797plb.10 for ; Fri, 18 May 2018 09:49:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:from:to:cc:subject:date :message-id:in-reply-to:references; bh=CjOooqcVKuHQTcqkzfyWrhOo6jQIUe+LRnxP5OSUqXI=; b=Cp/YY/lll9ckdoxQMPedoOD5EMQ2yc9BItMmmfHBv6OrAI9U03XsU5F19oRCCtXDG3 5HDVcxNSgerCUqdsfzV05Ourof92yL15drEbiPdD9tapoF7rHV35++w0AXbndT4OhLJV h2vWpR+ZzUKIF7fL/2sghpIjxD2OuNXGC/whliQ+l/Z0sSEGi3qKxrPnJwevEHrxUpdi /iX7Y7YXNHz3A2wRRuUe2iGMz/lM3t+oGVVqcMfqC1EGNkj9Ax4reoSwANCrNPYNXd3I IStizUeEGZxPP3lm17UDm719t5Hftz66gDBGCGxnbcJmeqTDba8v16g+aTKiFmRn2whh Juhg== X-Gm-Message-State: ALKqPwdRitBpgZPOylXstwxRmy238q9KOk6aoUjKV2hkOkdJa9RDV79c JnDzN01LLhZffVPQwSFJDzQL2j9ICNAx9bZN/ruutgF55KvExEAqdcK2GREh9UOMgO1DIvVb8VV RR1/qs2VNSonPxN1K3BkUSprkSVOP4FtUaoeAJhuqHg0tpIjFaE/A7LbYZjTGHko= X-Received: by 2002:a63:a44a:: with SMTP id c10-v6mr8097977pgp.147.1526662158648; Fri, 18 May 2018 09:49:18 -0700 (PDT) X-Google-Smtp-Source: AB8JxZpK8xettAkydeIgGRnwgTSSC4nkMTk93ARcxV02T00YeJZGNHiI5EHgXljIB8LGbt+jvfo9 X-Received: by 2002:a63:a44a:: with SMTP id c10-v6mr8097942pgp.147.1526662157791; Fri, 18 May 2018 09:49:17 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1526662157; cv=none; d=google.com; s=arc-20160816; b=O2nucCtuhxIXJE3wtTvbBzIC2aZmT1B6DVIVK5ShhR0uDeCVUPmkHpPwUKlkkubGQ7 V2PjmZObb90H15C4HrIpNGOVwuIE+EzADuwHfdDvznKxzusaKWjZ7ImLeF0NIu2f2OkL xi1J5GIHQ5wiHp6D1rtGl7Teja2+owtbPfmUp2/+4mzgyNVNQuNIf4fI39lL9HCFK0kk U6N54Nc54V7BT/PC0zNo1tS9bf99v+O8UWnnw8uOhnUeBn/MIaDRync5YvKBqdqloBeT exim3WY5p7YI2UXuVS2RI3WqKATL08K0EXvs+OLfU/19Zqb6g9SRUYkvb8IWFokdPp9y n7eg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature:arc-authentication-results; bh=CjOooqcVKuHQTcqkzfyWrhOo6jQIUe+LRnxP5OSUqXI=; b=FVeG0IAMeiKXEr5Bwp9f6sFPNBZne7d7sSnrKZVPYFXcXfRYsViWMRZraIZA0e7VpO Im/n0ycsimvR+FKiFt/446EvMZkdMlpf0GxlG+DdPPn+s6Xdgtv2nhC0cvqtI0FF5ycI rqpcYxR+ggcewqce8oYDYAnXgqaSE3NFCYfB2GvWZA8XXPEwnDCO5xROFrtaYvgSuXfC mVu3oPwAtEmwCZ4Mo9HxmHJAsiHM1/3D6nyhbsVa0NfO/4XlHqbZvrdVak5hWXaD0cYi GlyeVUpA+X3/SMsVAl+ZZMPRiolwYsdPAXhESejdXAoWF/Y+uAamqbZ7ZNeZkpddZhno 2Y8A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=UIUEqZDK; spf=pass (google.com: best guess record for domain of batv+77ddf8e9b1b344f28472+5381+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=BATV+77ddf8e9b1b344f28472+5381+infradead.org+hch@bombadil.srs.infradead.org Received: from bombadil.infradead.org (bombadil.infradead.org. [2607:7c80:54:e::133]) by mx.google.com with ESMTPS id 92-v6si7675683pli.280.2018.05.18.09.49.17 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 18 May 2018 09:49:17 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of batv+77ddf8e9b1b344f28472+5381+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=UIUEqZDK; spf=pass (google.com: best guess record for domain of batv+77ddf8e9b1b344f28472+5381+infradead.org+hch@bombadil.srs.infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=BATV+77ddf8e9b1b344f28472+5381+infradead.org+hch@bombadil.srs.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding: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=CjOooqcVKuHQTcqkzfyWrhOo6jQIUe+LRnxP5OSUqXI=; b=UIUEqZDKgYRXdS43WTtDlGqib ryRb+e62MZIv2MYovb/KGHF3W7tQrqKUvddUPRroMZZqYEAZ8vRGAvAjTH9dPFBqBzXhq83ZHMC/B y/AymOVEDSuGtevTkL4edDm7wvP880M45aq3GdYWhxGG3ThtJf9V6yQJ7zMCGJKczeKu15zp5ruvC fTxfiDahOHhuF9uq2OPZ9toi1Z9mzN6W3lU+Oxz/HFievCYzPCXBsZmnZWxyL7PYY+hcmU8VaEjNZ tyHXBagn5jKxCS/k2SUymWBwfudlgOF+3W08AJ8IPMR7IG0d1RnO263R1xdMfwVpHyOkLwYPwEsxP 4jnWr8u1A==; Received: from 80-109-164-210.cable.dynamic.surfer.at ([80.109.164.210] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1fJiZA-0006ZR-Tc; Fri, 18 May 2018 16:49:17 +0000 From: Christoph Hellwig To: linux-xfs@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 15/34] iomap: add an iomap-based readpage and readpages implementation Date: Fri, 18 May 2018 18:48:11 +0200 Message-Id: <20180518164830.1552-16-hch@lst.de> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180518164830.1552-1-hch@lst.de> References: <20180518164830.1552-1-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP Simply use iomap_apply to iterate over the file and a submit a bio for each non-uptodate but mapped region and zero everything else. Note that as-is this can not be used for file systems with a blocksize smaller than the page size, but that support will be added later. Signed-off-by: Christoph Hellwig --- fs/iomap.c | 200 +++++++++++++++++++++++++++++++++++++++++- include/linux/iomap.h | 4 + 2 files changed, 203 insertions(+), 1 deletion(-) diff --git a/fs/iomap.c b/fs/iomap.c index 7c1b071d115c..821671af2618 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -1,6 +1,6 @@ /* * Copyright (C) 2010 Red Hat, Inc. - * Copyright (c) 2016 Christoph Hellwig. + * Copyright (c) 2016-2018 Christoph Hellwig. * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -103,6 +104,203 @@ iomap_sector(struct iomap *iomap, loff_t pos) return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT; } +static inline bool +iomap_block_needs_zeroing(struct inode *inode, loff_t pos, struct iomap *iomap) +{ + return iomap->type != IOMAP_MAPPED || pos > i_size_read(inode); +} + +static void +iomap_read_end_io(struct bio *bio) +{ + int error = blk_status_to_errno(bio->bi_status); + struct bio_vec *bvec; + int i; + + bio_for_each_segment_all(bvec, bio, i) + page_endio(bvec->bv_page, false, error); + bio_put(bio); +} + +static struct bio * +iomap_read_bio_alloc(struct iomap *iomap, sector_t sector, loff_t length) +{ + int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT; + struct bio *bio = bio_alloc(GFP_NOFS, min(BIO_MAX_PAGES, nr_vecs)); + + bio->bi_opf = REQ_OP_READ; + bio->bi_iter.bi_sector = sector; + bio_set_dev(bio, iomap->bdev); + bio->bi_end_io = iomap_read_end_io; + return bio; +} + +struct iomap_readpage_ctx { + struct page *cur_page; + bool cur_page_in_bio; + struct bio *bio; + struct list_head *pages; +}; + +static loff_t +iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, + struct iomap *iomap) +{ + struct iomap_readpage_ctx *ctx = data; + struct page *page = ctx->cur_page; + unsigned poff = pos & (PAGE_SIZE - 1); + unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length); + bool is_contig = false; + sector_t sector; + + /* we don't support blocksize < PAGE_SIZE quite yet: */ + WARN_ON_ONCE(pos != page_offset(page)); + WARN_ON_ONCE(plen != PAGE_SIZE); + + if (iomap_block_needs_zeroing(inode, pos, iomap)) { + zero_user(page, poff, plen); + SetPageUptodate(page); + goto done; + } + + ctx->cur_page_in_bio = true; + + /* + * Try to merge into a previous segment if we can. + */ + sector = iomap_sector(iomap, pos); + if (ctx->bio && bio_end_sector(ctx->bio) == sector) { + if (__bio_try_merge_page(ctx->bio, page, plen, poff)) + goto done; + is_contig = true; + } + + if (!ctx->bio || !is_contig || bio_full(ctx->bio)) { + if (ctx->bio) + submit_bio(ctx->bio); + ctx->bio = iomap_read_bio_alloc(iomap, sector, length); + } + + __bio_add_page(ctx->bio, page, plen, poff); +done: + return plen; +} + +int +iomap_readpage(struct page *page, const struct iomap_ops *ops) +{ + struct iomap_readpage_ctx ctx = { .cur_page = page }; + struct inode *inode = page->mapping->host; + unsigned poff; + loff_t ret; + + WARN_ON_ONCE(page_has_buffers(page)); + + for (poff = 0; poff < PAGE_SIZE; poff += ret) { + ret = iomap_apply(inode, page_offset(page) + poff, + PAGE_SIZE - poff, 0, ops, &ctx, + iomap_readpage_actor); + if (ret <= 0) { + WARN_ON_ONCE(ret == 0); + SetPageError(page); + break; + } + } + + if (ctx.bio) { + submit_bio(ctx.bio); + WARN_ON_ONCE(!ctx.cur_page_in_bio); + } else { + WARN_ON_ONCE(ctx.cur_page_in_bio); + unlock_page(page); + } + return 0; +} +EXPORT_SYMBOL_GPL(iomap_readpage); + +static struct page * +iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, + loff_t length, loff_t *done) +{ + while (!list_empty(pages)) { + struct page *page = lru_to_page(pages); + + if (page_offset(page) >= (u64)pos + length) + break; + + list_del(&page->lru); + if (!add_to_page_cache_lru(page, inode->i_mapping, page->index, + GFP_NOFS)) + return page; + + *done += PAGE_SIZE; + put_page(page); + } + + return NULL; +} + +static loff_t +iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, + void *data, struct iomap *iomap) +{ + struct iomap_readpage_ctx *ctx = data; + loff_t done, ret; + + for (done = 0; done < length; done += ret) { + if (ctx->cur_page && ((pos + done) & (PAGE_SIZE - 1)) == 0) { + if (!ctx->cur_page_in_bio) + unlock_page(ctx->cur_page); + put_page(ctx->cur_page); + ctx->cur_page = NULL; + } + if (!ctx->cur_page) { + ctx->cur_page = iomap_next_page(inode, ctx->pages, + pos, length, &done); + if (!ctx->cur_page) + break; + ctx->cur_page_in_bio = false; + } + ret = iomap_readpage_actor(inode, pos + done, length - done, + ctx, iomap); + } + + return done; +} + +int +iomap_readpages(struct address_space *mapping, struct list_head *pages, + unsigned nr_pages, const struct iomap_ops *ops) +{ + struct iomap_readpage_ctx ctx = { .pages = pages }; + loff_t pos = page_offset(list_entry(pages->prev, struct page, lru)); + loff_t last = page_offset(list_entry(pages->next, struct page, lru)); + loff_t length = last - pos + PAGE_SIZE, ret = 0; + + while (length > 0) { + ret = iomap_apply(mapping->host, pos, length, 0, ops, + &ctx, iomap_readpages_actor); + if (ret <= 0) { + WARN_ON_ONCE(ret == 0); + goto done; + } + pos += ret; + length -= ret; + } + ret = 0; +done: + if (ctx.bio) + submit_bio(ctx.bio); + if (ctx.cur_page) { + if (!ctx.cur_page_in_bio) + unlock_page(ctx.cur_page); + put_page(ctx.cur_page); + } + WARN_ON_ONCE(!ret && !list_empty(ctx.pages)); + return ret; +} +EXPORT_SYMBOL_GPL(iomap_readpages); + static void iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) { diff --git a/include/linux/iomap.h b/include/linux/iomap.h index a044a824da85..7300d30ca495 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -9,6 +9,7 @@ struct fiemap_extent_info; struct inode; struct iov_iter; struct kiocb; +struct page; struct vm_area_struct; struct vm_fault; @@ -88,6 +89,9 @@ struct iomap_ops { ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from, const struct iomap_ops *ops); +int iomap_readpage(struct page *page, const struct iomap_ops *ops); +int iomap_readpages(struct address_space *mapping, struct list_head *pages, + unsigned nr_pages, const struct iomap_ops *ops); int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len, const struct iomap_ops *ops); int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len,