From: Namjae Jeon Subject: [PATCH v2] fat: fix data past EOF resulting from fsx testsuite Date: Wed, 12 Nov 2014 19:02:11 +0900 Message-ID: <009a01cffe5f$ba714f50$2f53edf0$@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org To: OGAWA Hirofumi , Andrew Morton Return-path: Received: from mailout4.samsung.com ([203.254.224.34]:33813 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751954AbaKLKCU (ORCPT ); Wed, 12 Nov 2014 05:02:20 -0500 Received: from epcpsbgr1.samsung.com (u141.gpu120.samsung.co.kr [203.254.230.141]) by mailout4.samsung.com (Oracle Communications Messaging Server 7u4-24.01 (7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NEX005G07VOJ550@mailout4.samsung.com> for linux-fsdevel@vger.kernel.org; Wed, 12 Nov 2014 19:02:12 +0900 (KST) Content-language: ko Sender: linux-fsdevel-owner@vger.kernel.org List-ID: When running FSX with direct I/O mode, fsx resulted in DATA past EOF issues. fsx ./file2 -Z -r 4096 -w 4096 ... .. truncating to largest ever: 0x907c fallocating to largest ever: 0x11137 truncating to largest ever: 0x2c6fe truncating to largest ever: 0x2cfdf fallocating to largest ever: 0x40000 Mapped Read: non-zero data past EOF (0x18628) page offset 0x629 is 0x2a4e ... .. The reason being, it is doing a truncate down, but the zeroing does not happen on the last block boundary when offset is not aligned. Even though it calls truncate_setsize()->truncate_inode_pages()-> truncate_inode_pages_range() and considers the partial zeroout but it retrieves the page using find_lock_page() - which only looks the page in the cache. So, zeroing out does not happen in case of direct IO. Make a truncate page based around block_truncate_page for FAT filesystem and invoke that helper to zerout in case the offset is not aligned with the blocksize. Signed-off-by: Namjae Jeon Signed-off-by: Amit Sahrawat --- fs/fat/fat.h | 1 + fs/fat/file.c | 3 +++ fs/fat/inode.c | 12 ++++++++++++ 3 files changed, 16 insertions(+) diff --git a/fs/fat/fat.h b/fs/fat/fat.h index eff027d..61801da 100644 --- a/fs/fat/fat.h +++ b/fs/fat/fat.h @@ -374,6 +374,7 @@ extern int fat_file_fsync(struct file *file, loff_t start, loff_t end, int datasync); /* fat/inode.c */ +extern int fat_block_truncate_page(struct inode *inode, loff_t from); extern void fat_attach(struct inode *inode, loff_t i_pos); extern void fat_detach(struct inode *inode); extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos); diff --git a/fs/fat/file.c b/fs/fat/file.c index f2c73ae..757fc20 100644 --- a/fs/fat/file.c +++ b/fs/fat/file.c @@ -523,6 +523,9 @@ int fat_setattr(struct dentry *dentry, struct iattr *attr) } if (attr->ia_valid & ATTR_SIZE) { + error = fat_block_truncate_page(inode, attr->ia_size); + if (error) + goto out; down_write(&MSDOS_I(inode)->truncate_lock); truncate_setsize(inode, attr->ia_size); fat_truncate_blocks(inode, attr->ia_size); diff --git a/fs/fat/inode.c b/fs/fat/inode.c index f362796..9bf44eb 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -339,6 +339,18 @@ static sector_t _fat_bmap(struct address_space *mapping, sector_t block) return blocknr; } +/* + * fat_block_truncate_page() zeroes out a mapping from file offset `from' + * up to the end of the block which corresponds to `from'. + * This is required during truncate to physically zeroout the tail end + * of that block so it doesn't yield old data if the file is later grown. + * Also, avoid causing failure from fsx for cases of "data past EOF" + */ +int fat_block_truncate_page(struct inode *inode, loff_t from) +{ + return block_truncate_page(inode->i_mapping, from, fat_get_block); +} + static const struct address_space_operations fat_aops = { .readpage = fat_readpage, .readpages = fat_readpages, -- 1.7.11-rc0