From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46976 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935288AbdAJKdM (ORCPT ); Tue, 10 Jan 2017 05:33:12 -0500 Subject: Patch "xfs: fix crash and data corruption due to removal of busy COW extents" has been added to the 4.9-stable tree To: hch@lst.de, darrick.wong@oracle.com, gregkh@linuxfoundation.org Cc: , From: Date: Tue, 10 Jan 2017 11:33:03 +0100 In-Reply-To: <1483976343-661-32-git-send-email-hch@lst.de> Message-ID: <148404438396115@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled xfs: fix crash and data corruption due to removal of busy COW extents to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xfs-fix-crash-and-data-corruption-due-to-removal-of-busy-cow-extents.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From hch@lst.de Tue Jan 10 11:31:19 2017 From: Christoph Hellwig Date: Mon, 9 Jan 2017 16:39:02 +0100 Subject: xfs: fix crash and data corruption due to removal of busy COW extents To: stable@vger.kernel.org Cc: linux-xfs@vger.kernel.org, "Darrick J. Wong" Message-ID: <1483976343-661-32-git-send-email-hch@lst.de> commit a1b7a4dea6166cf46be895bce4aac67ea5160fe8 upstream. There is a race window between write_cache_pages calling clear_page_dirty_for_io and XFS calling set_page_writeback, in which the mapping for an inode is tagged neither as dirty, nor as writeback. If the COW shrinker hits in exactly that window we'll remove the delayed COW extents and writepages trying to write it back, which in release kernels will manifest as corruption of the bmap btree, and in debug kernels will trip the ASSERT about now calling xfs_bmapi_write with the COWFORK flag for holes. A complex customer load manages to hit this window fairly reliably, probably by always having COW writeback in flight while the cow shrinker runs. This patch adds another check for having the I_DIRTY_PAGES flag set, which is still set during this race window. While this fixes the problem I'm still not overly happy about the way the COW shrinker works as it still seems a bit fragile. Signed-off-by: Christoph Hellwig Signed-off-by: Darrick J. Wong Cc: Christoph Hellwig Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_icache.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/xfs/xfs_icache.c +++ b/fs/xfs/xfs_icache.c @@ -1599,7 +1599,8 @@ xfs_inode_free_cowblocks( * If the mapping is dirty or under writeback we cannot touch the * CoW fork. Leave it alone if we're in the midst of a directio. */ - if (mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY) || + if ((VFS_I(ip)->i_state & I_DIRTY_PAGES) || + mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_DIRTY) || mapping_tagged(VFS_I(ip)->i_mapping, PAGECACHE_TAG_WRITEBACK) || atomic_read(&VFS_I(ip)->i_dio_count)) return 0; Patches currently in stable-queue which might be from hch@lst.de are queue-4.9/xfs-always-succeed-when-deduping-zero-bytes.patch queue-4.9/xfs-fix-crash-and-data-corruption-due-to-removal-of-busy-cow-extents.patch queue-4.9/xfs-don-t-allow-di_size-with-high-bit-set.patch queue-4.9/xfs-new-inode-extent-list-lookup-helpers.patch queue-4.9/xfs-don-t-call-xfs_sb_quota_from_disk-twice.patch queue-4.9/xfs-factor-rmap-btree-size-into-the-indlen-calculations.patch queue-4.9/xfs-check-return-value-of-_trans_reserve_quota_nblks.patch queue-4.9/xfs-complain-if-we-don-t-get-nextents-bmap-records.patch queue-4.9/xfs-check-for-bogus-values-in-btree-block-headers.patch queue-4.9/xfs-use-gpf_nofs-when-allocating-btree-cursors.patch queue-4.9/xfs-fix-max_retries-_show-and-_store-functions.patch queue-4.9/xfs-fix-double-cleanup-when-cui-recovery-fails.patch queue-4.9/xfs-don-t-skip-cow-forks-w-delalloc-blocks-in-cowblocks-scan.patch queue-4.9/xfs-track-preallocation-separately-in-xfs_bmapi_reserve_delalloc.patch queue-4.9/xfs-use-the-actual-ag-length-when-reserving-blocks.patch queue-4.9/xfs-ignore-leaf-attr-ichdr.count-in-verifier-during-log-replay.patch queue-4.9/xfs-pass-post-eof-speculative-prealloc-blocks-to-bmapi.patch queue-4.9/xfs-don-t-cap-maximum-dedupe-request-length.patch queue-4.9/xfs-pass-state-not-whichfork-to-trace_xfs_extlist.patch queue-4.9/xfs-move-agi-buffer-type-setting-to-xfs_read_agi.patch queue-4.9/xfs-check-minimum-block-size-for-crc-filesystems.patch queue-4.9/xfs-handle-cow-fork-in-xfs_bmap_trace_exlist.patch queue-4.9/pci-msi-check-for-null-affinity-mask-in-pci_irq_get_affinity.patch queue-4.9/xfs-error-out-if-trying-to-add-attrs-and-anextents-0.patch queue-4.9/xfs-don-t-bug-on-mixed-direct-and-mapped-i-o.patch queue-4.9/xfs-use-new-extent-lookup-helpers-xfs_file_iomap_begin_delay.patch queue-4.9/xfs-fix-unbalanced-inode-reclaim-flush-locking.patch queue-4.9/genirq-affinity-fix-node-generation-from-cpumask.patch queue-4.9/xfs-use-new-extent-lookup-helpers-in-__xfs_reflink_reserve_cow.patch queue-4.9/xfs-don-t-crash-if-reading-a-directory-results-in-an-unexpected-hole.patch queue-4.9/xfs-remove-prev-argument-to-xfs_bmapi_reserve_delalloc.patch queue-4.9/xfs-clean-up-cow-fork-reservation-and-tag-inodes-correctly.patch queue-4.9/xfs-forbid-ag-btrees-with-level-0.patch queue-4.9/xfs-provide-helper-for-counting-extents-from-if_bytes.patch