From patchwork Sat Oct 3 05:56:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chandan Babu R X-Patchwork-Id: 11815059 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0E98E6CA for ; Sat, 3 Oct 2020 05:56:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D75BA206DD for ; Sat, 3 Oct 2020 05:56:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sQ4Indrh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725648AbgJCF4s (ORCPT ); Sat, 3 Oct 2020 01:56:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725446AbgJCF4s (ORCPT ); Sat, 3 Oct 2020 01:56:48 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1AB3C0613D0 for ; Fri, 2 Oct 2020 22:56:46 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id q4so2441809pjh.5 for ; Fri, 02 Oct 2020 22:56:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=b8ZuztcBYLWQqVQ3emWtfAW71IKOUR0iF+Lp7SCxAB4=; b=sQ4Indrhc7bNV2wpK1JUZeWo9GSR3h5t35p3Vs2cq9JPAdZ8Q0ohlHWBhdD29LXsFR 7x9kMuZDR6J3J2Q/xUmJo0B0c6foUuqwPlcmfZoVKiG3lVCgFjlfgnFAf2+zxNXBnV5B b6YX44pfmQzIzF0sinMUVmCLNFUhqpO12nGnI2aqmK5TZFWUmywycKpY9kKAFRmh59C8 /hO9D8Kb3aT+THg/szdUus28t9sKSW3WV+zIteec9RBEXhhNfjgFGIUMqQr4QCVe8Pc3 Gw49/sR3rz8pyGlSBlJW3jzzNVBoNqAGTfUhN5XF3KXmvu0jCOu+xxyo1DNLflyzHq7g eHyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=b8ZuztcBYLWQqVQ3emWtfAW71IKOUR0iF+Lp7SCxAB4=; b=e5xzm1BXkOjocFCaWvtniHLr4FUaSIAmocpm5bdZK68okOZUsT9TnrdW4CouY5Nxgo EFJFuWxxVEWMtfA0HC5oX375mT4ZsKRfKS1dEG9kGX3Nc0hx2+6Wm67rsl0mPBJ7T/MR aG3HMySYvf74fZ8dD+thag1ESYea0Mmwo9H2W7dhbC2FYwK7P72jqxMB1YgrpJcvMTU4 MXZgNu9A4TS0AG0sVzhPqc+hBlvJ4G+LENaTNhC8+7OYyHbscopQeRcQZVsT/UdFkcbv xBNq7aGpNmJzOwtRsUzdQxSgB0zn0jERzUOTRXsfUqSzjkrnHxox3v1cKWPxNFnf7TXC jCvg== X-Gm-Message-State: AOAM532P2rDoHA/h9mbvLA1UXrOcLwXYiyQZrA2hUuaZG/u2OgRdq8vg SBP9Y+7yL6IewbrneebAKtDvUe2lcHQ= X-Google-Smtp-Source: ABdhPJxcgNZ4Rv39C/BY77Qw+XVtf+b1V6JoqD/rUcmxHpNzXf7S1o5cklCvQhLTQGHgp1W9+F86sA== X-Received: by 2002:a17:90b:384c:: with SMTP id nl12mr5281081pjb.166.1601704605748; Fri, 02 Oct 2020 22:56:45 -0700 (PDT) Received: from localhost.localdomain ([122.171.168.96]) by smtp.gmail.com with ESMTPSA id 125sm4106664pff.59.2020.10.02.22.56.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 02 Oct 2020 22:56:45 -0700 (PDT) From: Chandan Babu R To: linux-xfs@vger.kernel.org Cc: Chandan Babu R , darrick.wong@oracle.com, david@fromorbit.com Subject: [PATCH V5 00/12] Bail out if transaction can cause extent count to overflow Date: Sat, 3 Oct 2020 11:26:21 +0530 Message-Id: <20201003055633.9379-1-chandanrlinux@gmail.com> X-Mailer: git-send-email 2.28.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org XFS does not check for possible overflow of per-inode extent counter fields when adding extents to either data or attr fork. For e.g. 1. Insert 5 million xattrs (each having a value size of 255 bytes) and then delete 50% of them in an alternating manner. 2. On a 4k block sized XFS filesystem instance, the above causes 98511 extents to be created in the attr fork of the inode. xfsaild/loop0 2008 [003] 1475.127209: probe:xfs_inode_to_disk: (ffffffffa43fb6b0) if_nextents=98511 i_ino=131 3. The incore inode fork extent counter is a signed 32-bit quantity. However, the on-disk extent counter is an unsigned 16-bit quantity and hence cannot hold 98511 extents. 4. The following incorrect value is stored in the xattr extent counter, # xfs_db -f -c 'inode 131' -c 'print core.naextents' /dev/loop0 core.naextents = -32561 This patchset adds a new helper function (i.e. xfs_iext_count_may_overflow()) to check for overflow of the per-inode data and xattr extent counters and invokes it before starting an fs operation (e.g. creating a new directory entry). With this patchset applied, XFS detects counter overflows and returns with an error rather than causing a silent corruption. The patchset has been tested by executing xfstests with the following mkfs.xfs options, 1. -m crc=0 -b size=1k 2. -m crc=0 -b size=4k 3. -m crc=0 -b size=512 4. -m rmapbt=1,reflink=1 -b size=1k 5. -m rmapbt=1,reflink=1 -b size=4k The patches can also be obtained from https://github.com/chandanr/linux.git at branch xfs-reserve-extent-count-v5. I have two patches that define the newly introduced error injection tags in xfsprogs (https://github.com/chandanr/xfsprogs-dev/commit/7fd7aeef1cefbcc9abd6dd5887e710c80e48079d and https://github.com/chandanr/xfsprogs-dev/commit/3cbe12f6fdf306de06c4096eb50641fa2d834dc5). I have also written tests (https://github.com/chandanr/check-iext-overflow/blob/master/check-iext-overflow.sh/) for verifying the checks introduced in the kernel. The tests have to be edited to make them suitable for merging with xfstests. But they also depend on error tags introduced in these patches . Hence, I am planning to post the changes for xfsprogs and xfstests if other developers are fine with the changes made in this patchset. Changelog: V4 -> V5: 1. Introduce new error tag XFS_ERRTAG_BMAP_ALLOC_MINLEN_EXTENT to let user space programs to be able to guarantee that free space requests for files are satisfied by allocating minlen sized extents. 2. Change xfs_bmap_btalloc() and xfs_alloc_vextent() to allocate minlen sized extents when XFS_ERRTAG_BMAP_ALLOC_MINLEN_EXTENT is enabled. 3. Introduce a new patch that causes tp->t_firstblock to be assigned to a value only when its previous value is NULLFSBLOCK. 4. Replace the previously introduced MAXERRTAGEXTNUM (maximum inode fork extent count) with the hardcoded value of 10. 5. xfs_bui_item_recover(): Use XFS_IEXT_ADD_NOSPLIT_CNT when mapping an extent. 6. xfs_swap_extent_rmap(): Use xfs_bmap_is_real_extent() instead of xfs_bmap_is_update_needed() to assess if the extent really needs to be swapped. V3 -> V4: 1. Introduce new patch which lets userspace programs to test "extent count overflow detection" by injecting an error tag. The new error tag reduces the maximum allowed extent count to 10. 2. Injecting the newly defined error tag prevents xfs_bmap_add_extent_hole_real() from merging a new extent with its neighbours to allow writing deterministic tests for testing extent count overflow for Directories, Xattr and growing realtime devices. This is required because the new extent being allocated can be contiguous with its neighbours (w.r.t both file and disk offsets). 3. Injecting the newly defined error tag forces block sized extents to be allocated for summary/bitmap files when growing a realtime device. This is required because xfs_growfs_rt_alloc() allocates as large an extent as possible for summary/bitmap files and hence it would be impossible to write deterministic tests. 4. Rename XFS_IEXT_REMOVE_CNT to XFS_IEXT_PUNCH_HOLE_CNT to reflect the actual meaning of the fs operation. 5. Fold XFS_IEXT_INSERT_HOLE_CNT code into that associated with XFS_IEXT_PUNCH_HOLE_CNT since both perform the same job. 6. xfs_swap_extent_rmap(): Check for extent overflow should be made on the source file only if the donor file extent has a valid on-disk mapping and vice versa. V2 -> V3: 1. Move the definition of xfs_iext_count_may_overflow() from libxfs/xfs_trans_resv.c to libxfs/xfs_inode_fork.c. Also, I tried to make xfs_iext_count_may_overflow() an inline function by placing the definition in libxfs/xfs_inode_fork.h. However this required that the definition of 'struct xfs_inode' be available, since xfs_iext_count_may_overflow() uses a 'struct xfs_inode *' type variable. 2. Handle XFS_COW_FORK within xfs_iext_count_may_overflow() by returning a success value. 3. Rename XFS_IEXT_ADD_CNT to XFS_IEXT_ADD_NOSPLIT_CNT. Thanks to Darrick for the suggesting the new name. 4. Expand comments to make use of 80 columns. V1 -> V2: 1. Rename helper function from xfs_trans_resv_ext_cnt() to xfs_iext_count_may_overflow(). 2. Define and use macros to represent fs operations and the corresponding increase in extent count. 3. Split the patches based on the fs operation being performed. Chandan Babu R (12): xfs: Add helper for checking per-inode extent count overflow xfs: Check for extent overflow when trivally adding a new extent xfs: Check for extent overflow when punching a hole xfs: Check for extent overflow when adding/removing xattrs xfs: Check for extent overflow when adding/removing dir entries xfs: Check for extent overflow when writing to unwritten extent xfs: Check for extent overflow when moving extent from cow to data fork xfs: Check for extent overflow when remapping an extent xfs: Check for extent overflow when swapping extents xfs: Introduce error injection to reduce maximum inode fork extent count xfs: Set tp->t_firstblock only once during a transaction's lifetime xfs: Introduce error injection to allocate only minlen size extents for files fs/xfs/libxfs/xfs_alloc.c | 46 ++++++++++++++++++++ fs/xfs/libxfs/xfs_alloc.h | 1 + fs/xfs/libxfs/xfs_attr.c | 13 ++++++ fs/xfs/libxfs/xfs_bmap.c | 38 +++++++++++++---- fs/xfs/libxfs/xfs_errortag.h | 6 ++- fs/xfs/libxfs/xfs_inode_fork.c | 27 ++++++++++++ fs/xfs/libxfs/xfs_inode_fork.h | 77 ++++++++++++++++++++++++++++++++++ fs/xfs/xfs_bmap_item.c | 10 +++++ fs/xfs/xfs_bmap_util.c | 31 ++++++++++++++ fs/xfs/xfs_dquot.c | 8 +++- fs/xfs/xfs_error.c | 6 +++ fs/xfs/xfs_inode.c | 27 ++++++++++++ fs/xfs/xfs_iomap.c | 10 +++++ fs/xfs/xfs_reflink.c | 10 +++++ fs/xfs/xfs_rtalloc.c | 5 +++ fs/xfs/xfs_symlink.c | 5 +++ 16 files changed, 309 insertions(+), 11 deletions(-)