From patchwork Sat Jun 29 07:30:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chao Yu X-Patchwork-Id: 11023737 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 90A851398 for ; Sat, 29 Jun 2019 07:30:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 928A828517 for ; Sat, 29 Jun 2019 07:30:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8654828514; Sat, 29 Jun 2019 07:30:48 +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=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D61B828553 for ; Sat, 29 Jun 2019 07:30:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726810AbfF2Hao (ORCPT ); Sat, 29 Jun 2019 03:30:44 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:2960 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726527AbfF2Hao (ORCPT ); Sat, 29 Jun 2019 03:30:44 -0400 Received: from DGGEMM403-HUB.china.huawei.com (unknown [172.30.72.53]) by Forcepoint Email with ESMTP id 09ED22C58F7AE824AD79; Sat, 29 Jun 2019 15:30:40 +0800 (CST) Received: from dggeme763-chm.china.huawei.com (10.3.19.109) by DGGEMM403-HUB.china.huawei.com (10.3.20.211) with Microsoft SMTP Server (TLS) id 14.3.439.0; Sat, 29 Jun 2019 15:30:39 +0800 Received: from szvp000201624.huawei.com (10.120.216.130) by dggeme763-chm.china.huawei.com (10.3.19.109) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1591.10; Sat, 29 Jun 2019 15:30:39 +0800 From: Chao Yu To: , CC: , , , , Chao Yu Subject: [PATCH RFC] iomap: introduce IOMAP_TAIL Date: Sat, 29 Jun 2019 15:30:20 +0800 Message-ID: <20190629073020.22759-1-yuchao0@huawei.com> X-Mailer: git-send-email 2.18.0.rc1 MIME-Version: 1.0 X-Originating-IP: [10.120.216.130] X-ClientProxiedBy: dggeme713-chm.china.huawei.com (10.1.199.109) To dggeme763-chm.china.huawei.com (10.3.19.109) X-CFilter-Loop: Reflected Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Some filesystems like erofs/reiserfs have the ability to pack tail data into metadata, however iomap framework can only support mapping inline data with IOMAP_INLINE type, it restricts that: - inline data should be locating at page #0. - inline size should equal to .i_size So we can not use IOMAP_INLINE to handle tail-packing case. This patch introduces new mapping type IOMAP_TAIL to map tail-packed data for further use of erofs. Signed-off-by: Chao Yu --- fs/iomap.c | 22 ++++++++++++++++++++++ include/linux/iomap.h | 1 + 2 files changed, 23 insertions(+) diff --git a/fs/iomap.c b/fs/iomap.c index 12654c2e78f8..ae7777ce77d0 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -280,6 +280,23 @@ iomap_read_inline_data(struct inode *inode, struct page *page, SetPageUptodate(page); } +static void +iomap_read_tail_data(struct inode *inode, struct page *page, + struct iomap *iomap) +{ + size_t size = i_size_read(inode) & (PAGE_SIZE - 1); + void *addr; + + if (PageUptodate(page)) + return; + + addr = kmap_atomic(page); + memcpy(addr, iomap->inline_data, size); + memset(addr + size, 0, PAGE_SIZE - size); + kunmap_atomic(addr); + SetPageUptodate(page); +} + static loff_t iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) @@ -298,6 +315,11 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, return PAGE_SIZE; } + if (iomap->type == IOMAP_TAIL) { + iomap_read_tail_data(inode, page, iomap); + return PAGE_SIZE; + } + /* zero post-eof blocks as the page may be mapped */ iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen); if (plen == 0) diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 2103b94cb1bf..7e1ee48e3db7 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -25,6 +25,7 @@ struct vm_fault; #define IOMAP_MAPPED 0x03 /* blocks allocated at @addr */ #define IOMAP_UNWRITTEN 0x04 /* blocks allocated at @addr in unwritten state */ #define IOMAP_INLINE 0x05 /* data inline in the inode */ +#define IOMAP_TAIL 0x06 /* tail data packed in metdata */ /* * Flags for all iomap mappings: