From patchwork Tue Jul 27 02:59:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gao Xiang X-Patchwork-Id: 12401259 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=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 104D1C4338F for ; Tue, 27 Jul 2021 03:00:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E1D2860FF2 for ; Tue, 27 Jul 2021 03:00:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234533AbhG0CTt (ORCPT ); Mon, 26 Jul 2021 22:19:49 -0400 Received: from out4436.biz.mail.alibaba.com ([47.88.44.36]:23162 "EHLO out4436.biz.mail.alibaba.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234410AbhG0CTr (ORCPT ); Mon, 26 Jul 2021 22:19:47 -0400 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 Cc: LKML , Huang Jianan , Joseph Qi , Gao Xiang , "Darrick J . Wong" , Christoph Hellwig , Matthew Wilcox , Andreas Gruenbacher 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 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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