From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:42132 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731911AbeKTDHv (ORCPT ); Mon, 19 Nov 2018 22:07:51 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Filipe Manana , Robbie Ko , David Sterba Subject: [PATCH 4.18 101/171] Btrfs: fix cur_offset in the error case for nocow Date: Mon, 19 Nov 2018 17:28:17 +0100 Message-Id: <20181119162635.009393449@linuxfoundation.org> In-Reply-To: <20181119162618.909354448@linuxfoundation.org> References: <20181119162618.909354448@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Robbie Ko commit 506481b20e818db40b6198815904ecd2d6daee64 upstream. When the cow_file_range fails, the related resources are unlocked according to the range [start..end), so the unlock cannot be repeated in run_delalloc_nocow. In some cases (e.g. cur_offset <= end && cow_start != -1), cur_offset is not updated correctly, so move the cur_offset update before cow_file_range. kernel BUG at mm/page-writeback.c:2663! Internal error: Oops - BUG: 0 [#1] SMP CPU: 3 PID: 31525 Comm: kworker/u8:7 Tainted: P O Hardware name: Realtek_RTD1296 (DT) Workqueue: writeback wb_workfn (flush-btrfs-1) task: ffffffc076db3380 ti: ffffffc02e9ac000 task.ti: ffffffc02e9ac000 PC is at clear_page_dirty_for_io+0x1bc/0x1e8 LR is at clear_page_dirty_for_io+0x14/0x1e8 pc : [] lr : [] pstate: 40000145 sp : ffffffc02e9af4f0 Process kworker/u8:7 (pid: 31525, stack limit = 0xffffffc02e9ac020) Call trace: [] clear_page_dirty_for_io+0x1bc/0x1e8 [] extent_clear_unlock_delalloc+0x1e4/0x210 [btrfs] [] run_delalloc_nocow+0x3b8/0x948 [btrfs] [] run_delalloc_range+0x250/0x3a8 [btrfs] [] writepage_delalloc.isra.21+0xbc/0x1d8 [btrfs] [] __extent_writepage+0xe8/0x248 [btrfs] [] extent_write_cache_pages.isra.17+0x164/0x378 [btrfs] [] extent_writepages+0x48/0x68 [btrfs] [] btrfs_writepages+0x20/0x30 [btrfs] [] do_writepages+0x30/0x88 [] __writeback_single_inode+0x34/0x198 [] writeback_sb_inodes+0x184/0x3c0 [] __writeback_inodes_wb+0x6c/0xc0 [] wb_writeback+0x1b8/0x1c0 [] wb_workfn+0x150/0x250 [] process_one_work+0x1dc/0x388 [] worker_thread+0x130/0x500 [] kthread+0x10c/0x110 [] ret_from_fork+0x10/0x40 Code: d503201f a9025bb5 a90363b7 f90023b9 (d4210000) CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana Signed-off-by: Robbie Ko Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/inode.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -1537,12 +1537,11 @@ out_check: } btrfs_release_path(path); - if (cur_offset <= end && cow_start == (u64)-1) { + if (cur_offset <= end && cow_start == (u64)-1) cow_start = cur_offset; - cur_offset = end; - } if (cow_start != (u64)-1) { + cur_offset = end; ret = cow_file_range(inode, locked_page, cow_start, end, end, page_started, nr_written, 1, NULL); if (ret)