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,UNPARSEABLE_RELAY,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 7CFEAC4338F for ; Tue, 27 Jul 2021 03:00:25 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D313F6101E for ; Tue, 27 Jul 2021 03:00:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D313F6101E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.ozlabs.org Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4GYhP33kmPz3089 for ; Tue, 27 Jul 2021 13:00:23 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.alibaba.com (client-ip=115.124.30.56; helo=out30-56.freemail.mail.aliyun.com; envelope-from=hsiangkao@linux.alibaba.com; receiver=) Received: from out30-56.freemail.mail.aliyun.com (out30-56.freemail.mail.aliyun.com [115.124.30.56]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4GYhNr3RzNz2yLZ for ; Tue, 27 Jul 2021 13:00:10 +1000 (AEST) X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R351e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e01424; MF=hsiangkao@linux.alibaba.com; NM=1; PH=DS; RN=10; SR=0; TI=SMTPD_---0Uh6wb0w_1627354798; Received: from e18g09479.et15sqa.tbsite.net(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0Uh6wb0w_1627354798) by smtp.aliyun-inc.com(127.0.0.1); Tue, 27 Jul 2021 11:00:02 +0800 From: Gao Xiang To: linux-erofs@lists.ozlabs.org, linux-fsdevel@vger.kernel.org Subject: [PATCH v9] iomap: Support file tail packing Date: Tue, 27 Jul 2021 10:59:56 +0800 Message-Id: <20210727025956.80684-1-hsiangkao@linux.alibaba.com> X-Mailer: git-send-email 2.24.4 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: linux-erofs@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Development of Linux EROFS file system List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Andreas Gruenbacher , "Darrick J . Wong" , LKML , Matthew Wilcox , Joseph Qi , Christoph Hellwig Errors-To: linux-erofs-bounces+linux-erofs=archiver.kernel.org@lists.ozlabs.org Sender: "Linux-erofs" The existing inline data support only works for cases where the entire file is stored as inline data. For larger files, EROFS stores the initial blocks separately and then can pack a small tail adjacent to the inode. Generalise inline data to allow for tail packing. Tails may not cross a page boundary in memory. We currently have no filesystems that support tail packing and writing, so that case is currently disabled (see iomap_write_begin_inline). Cc: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Matthew Wilcox (Oracle) Signed-off-by: Andreas Gruenbacher Signed-off-by: Gao Xiang --- v8: https://lore.kernel.org/r/20210726145734.214295-1-hsiangkao@linux.alibaba.com changes since v8: - update the subject to 'iomap: Support file tail packing' as there are clearly a number of ways to make the inline data support more flexible (Matthew); - add one extra safety check (Darrick): if (WARN_ON_ONCE(size > iomap->length)) return -EIO; fs/iomap/buffered-io.c | 42 ++++++++++++++++++++++++++++++------------ fs/iomap/direct-io.c | 10 ++++++---- include/linux/iomap.h | 18 ++++++++++++++++++ 3 files changed, 54 insertions(+), 16 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 87ccb3438bec..f429b9d87dbe 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -205,25 +205,32 @@ struct iomap_readpage_ctx { struct readahead_control *rac; }; -static void -iomap_read_inline_data(struct inode *inode, struct page *page, +static int iomap_read_inline_data(struct inode *inode, struct page *page, struct iomap *iomap) { - size_t size = i_size_read(inode); + size_t size = i_size_read(inode) - iomap->offset; void *addr; if (PageUptodate(page)) - return; + return 0; - BUG_ON(page_has_private(page)); - BUG_ON(page->index); - BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data)); + /* inline data must start page aligned in the file */ + if (WARN_ON_ONCE(offset_in_page(iomap->offset))) + return -EIO; + if (WARN_ON_ONCE(size > PAGE_SIZE - + offset_in_page(iomap->inline_data))) + return -EIO; + if (WARN_ON_ONCE(size > iomap->length)) + return -EIO; + if (WARN_ON_ONCE(page_has_private(page))) + return -EIO; addr = kmap_atomic(page); memcpy(addr, iomap->inline_data, size); memset(addr + size, 0, PAGE_SIZE - size); kunmap_atomic(addr); SetPageUptodate(page); + return 0; } static inline bool iomap_block_needs_zeroing(struct inode *inode, @@ -247,8 +254,10 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, sector_t sector; if (iomap->type == IOMAP_INLINE) { - WARN_ON_ONCE(pos); - iomap_read_inline_data(inode, page, iomap); + int ret = iomap_read_inline_data(inode, page, iomap); + + if (ret) + return ret; return PAGE_SIZE; } @@ -589,6 +598,15 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags, return 0; } +static int iomap_write_begin_inline(struct inode *inode, + struct page *page, struct iomap *srcmap) +{ + /* needs more work for the tailpacking case, disable for now */ + if (WARN_ON_ONCE(srcmap->offset != 0)) + return -EIO; + return iomap_read_inline_data(inode, page, srcmap); +} + static int iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, struct page **pagep, struct iomap *iomap, struct iomap *srcmap) @@ -618,7 +636,7 @@ iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, } if (srcmap->type == IOMAP_INLINE) - iomap_read_inline_data(inode, page, srcmap); + status = iomap_write_begin_inline(inode, page, srcmap); else if (iomap->flags & IOMAP_F_BUFFER_HEAD) status = __block_write_begin_int(page, pos, len, NULL, srcmap); else @@ -671,11 +689,11 @@ static size_t iomap_write_end_inline(struct inode *inode, struct page *page, void *addr; WARN_ON_ONCE(!PageUptodate(page)); - BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data)); + BUG_ON(!iomap_inline_data_valid(iomap)); flush_dcache_page(page); addr = kmap_atomic(page); - memcpy(iomap->inline_data + pos, addr + pos, copied); + memcpy(iomap_inline_data(iomap, pos), addr + pos, copied); kunmap_atomic(addr); mark_inode_dirty(inode); diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 9398b8c31323..41ccbfc9dc82 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -378,23 +378,25 @@ iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length, struct iomap_dio *dio, struct iomap *iomap) { struct iov_iter *iter = dio->submit.iter; + void *inline_data = iomap_inline_data(iomap, pos); size_t copied; - BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data)); + if (WARN_ON_ONCE(!iomap_inline_data_valid(iomap))) + return -EIO; if (dio->flags & IOMAP_DIO_WRITE) { loff_t size = inode->i_size; if (pos > size) - memset(iomap->inline_data + size, 0, pos - size); - copied = copy_from_iter(iomap->inline_data + pos, length, iter); + memset(iomap_inline_data(iomap, size), 0, pos - size); + copied = copy_from_iter(inline_data, length, iter); if (copied) { if (pos + copied > size) i_size_write(inode, pos + copied); mark_inode_dirty(inode); } } else { - copied = copy_to_iter(iomap->inline_data + pos, length, iter); + copied = copy_to_iter(inline_data, length, iter); } dio->size += copied; return copied; diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 479c1da3e221..b8ec145b2975 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -97,6 +97,24 @@ iomap_sector(struct iomap *iomap, loff_t pos) return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT; } +/* + * Returns the inline data pointer for logical offset @pos. + */ +static inline void *iomap_inline_data(struct iomap *iomap, loff_t pos) +{ + return iomap->inline_data + pos - iomap->offset; +} + +/* + * Check if the mapping's length is within the valid range for inline data. + * This is used to guard against accessing data beyond the page inline_data + * points at. + */ +static inline bool iomap_inline_data_valid(struct iomap *iomap) +{ + return iomap->length <= PAGE_SIZE - offset_in_page(iomap->inline_data); +} + /* * When a filesystem sets page_ops in an iomap mapping it returns, page_prepare * and page_done will be called for each page written to. This only applies to -- 2.24.4