From patchwork Tue Mar 7 04:24:49 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Filipe Manana X-Patchwork-Id: 9609633 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id ED0AC6016C for ; Tue, 7 Mar 2017 18:36:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DCA9D28400 for ; Tue, 7 Mar 2017 18:36:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D001128505; Tue, 7 Mar 2017 18:36:32 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.9 required=2.0 tests=BAYES_00, DATE_IN_PAST_12_24, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E079428400 for ; Tue, 7 Mar 2017 18:36:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932824AbdCGSga (ORCPT ); Tue, 7 Mar 2017 13:36:30 -0500 Received: from mail.kernel.org ([198.145.29.136]:47390 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932639AbdCGSg2 (ORCPT ); Tue, 7 Mar 2017 13:36:28 -0500 Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id E100620411 for ; Tue, 7 Mar 2017 18:36:15 +0000 (UTC) Received: from debian3.lan (bl12-226-64.dsl.telepac.pt [85.245.226.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3A43820426 for ; Tue, 7 Mar 2017 18:36:14 +0000 (UTC) From: fdmanana@kernel.org To: linux-btrfs@vger.kernel.org Subject: [PATCH v2] Btrfs: fix invalid attempt to free reserved space on failure to cow range Date: Tue, 7 Mar 2017 04:24:49 +0000 Message-Id: <1488860689-6008-1-git-send-email-fdmanana@kernel.org> X-Mailer: git-send-email 2.7.0.rc3 X-Virus-Scanned: ClamAV using ClamSMTP Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Filipe Manana When attempting to COW a file range (we are starting writeback and doing COW), if we manage to reserve an extent for the range we will write into but fail after reserving it and before creating the respective ordered extent, we end up in an error path where we attempt to decrement the data space's bytes_may_use counter after we already did it while reserving the extent, leading to a warning/trace like the following: [ 847.621524] ------------[ cut here ]------------ [ 847.625441] WARNING: CPU: 5 PID: 4905 at fs/btrfs/extent-tree.c:4316 btrfs_free_reserved_data_space_noquota+0x60/0x9f [btrfs] [ 847.633704] Modules linked in: btrfs crc32c_generic xor raid6_pq acpi_cpufreq i2c_piix4 ppdev psmouse tpm_tis serio_raw pcspkr parport_pc tpm_tis_core i2c_core sg [ 847.644616] CPU: 5 PID: 4905 Comm: xfs_io Not tainted 4.10.0-rc8-btrfs-next-37+ #2 [ 847.648601] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014 [ 847.648601] Call Trace: [ 847.648601] dump_stack+0x67/0x90 [ 847.648601] __warn+0xc2/0xdd [ 847.648601] warn_slowpath_null+0x1d/0x1f [ 847.648601] btrfs_free_reserved_data_space_noquota+0x60/0x9f [btrfs] [ 847.648601] btrfs_clear_bit_hook+0x140/0x258 [btrfs] [ 847.648601] clear_state_bit+0x87/0x128 [btrfs] [ 847.648601] __clear_extent_bit+0x222/0x2b7 [btrfs] [ 847.648601] clear_extent_bit+0x17/0x19 [btrfs] [ 847.648601] extent_clear_unlock_delalloc+0x3b/0x6b [btrfs] [ 847.648601] cow_file_range.isra.39+0x387/0x39a [btrfs] [ 847.648601] run_delalloc_nocow+0x4d7/0x70e [btrfs] [ 847.648601] ? arch_local_irq_save+0x9/0xc [ 847.648601] run_delalloc_range+0xa7/0x2b5 [btrfs] [ 847.648601] writepage_delalloc.isra.31+0xb9/0x15c [btrfs] [ 847.648601] __extent_writepage+0x249/0x2e8 [btrfs] [ 847.648601] extent_write_cache_pages.constprop.33+0x28b/0x36c [btrfs] [ 847.648601] ? arch_local_irq_save+0x9/0xc [ 847.648601] ? mark_lock+0x24/0x201 [ 847.648601] extent_writepages+0x4b/0x5c [btrfs] [ 847.648601] ? btrfs_writepage_start_hook+0xed/0xed [btrfs] [ 847.648601] btrfs_writepages+0x28/0x2a [btrfs] [ 847.648601] do_writepages+0x23/0x2c [ 847.648601] __filemap_fdatawrite_range+0x5a/0x61 [ 847.648601] filemap_fdatawrite_range+0x13/0x15 [ 847.648601] btrfs_fdatawrite_range+0x20/0x46 [btrfs] [ 847.648601] start_ordered_ops+0x19/0x23 [btrfs] [ 847.648601] btrfs_sync_file+0x136/0x42c [btrfs] [ 847.648601] vfs_fsync_range+0x8c/0x9e [ 847.648601] vfs_fsync+0x1c/0x1e [ 847.648601] do_fsync+0x31/0x4a [ 847.648601] SyS_fsync+0x10/0x14 [ 847.648601] entry_SYSCALL_64_fastpath+0x18/0xad [ 847.648601] RIP: 0033:0x7f5b05200800 [ 847.648601] RSP: 002b:00007ffe204f71c8 EFLAGS: 00000246 ORIG_RAX: 000000000000004a [ 847.648601] RAX: ffffffffffffffda RBX: ffffffff8109637b RCX: 00007f5b05200800 [ 847.648601] RDX: 00000000008bd0a0 RSI: 00000000008bd2e0 RDI: 0000000000000003 [ 847.648601] RBP: ffffc90001d67f98 R08: 000000000000ffff R09: 000000000000001f [ 847.648601] R10: 00000000000001f6 R11: 0000000000000246 R12: 0000000000000046 [ 847.648601] R13: ffffc90001d67f78 R14: 00007f5b054be740 R15: 00007f5b054be740 [ 847.648601] ? trace_hardirqs_off_caller+0x3f/0xaa [ 847.685787] ---[ end trace 2a4a3e15382508e8 ]--- So fix this by not attempting to decrement the data space info's bytes_may_use counter if we already reserved the extent and an error happened before creating the ordered extent. We are already correctly freeing the reserved extent if an error happens, so there's no additional measure needed. Signed-off-by: Filipe Manana --- V2: Removed previous dependence on a no longer needed cleanup patch and rebased it on top of Qu's recent patchset that fixes hanging ordered extents when errors happen. fs/btrfs/extent_io.h | 4 +++- fs/btrfs/inode.c | 56 ++++++++++++++++++++++++++++++++++++++-------------- 2 files changed, 44 insertions(+), 16 deletions(-) diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h index 3e4fad4..d31313d 100644 --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h @@ -21,8 +21,10 @@ #define EXTENT_NORESERVE (1U << 15) #define EXTENT_QGROUP_RESERVED (1U << 16) #define EXTENT_CLEAR_DATA_RESV (1U << 17) +#define EXTENT_SPACE_FREED (1U << 18) #define EXTENT_IOBITS (EXTENT_LOCKED | EXTENT_WRITEBACK) -#define EXTENT_CTLBITS (EXTENT_DO_ACCOUNTING | EXTENT_FIRST_DELALLOC) +#define EXTENT_CTLBITS (EXTENT_DO_ACCOUNTING | EXTENT_FIRST_DELALLOC |\ + EXTENT_SPACE_FREED) /* * flags for bio submission. The high bits indicate the compression diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 9b03eb9b..9714453 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -942,10 +942,13 @@ static noinline int cow_file_range(struct inode *inode, u64 num_bytes; unsigned long ram_size; u64 disk_num_bytes; - u64 cur_alloc_size; + u64 cur_alloc_size = 0; u64 blocksize = fs_info->sectorsize; struct btrfs_key ins; struct extent_map *em; + unsigned clear_bits; + unsigned long page_ops; + bool extent_reserved = false; int ret = 0; if (btrfs_is_free_space_inode(BTRFS_I(inode))) { @@ -990,14 +993,14 @@ static noinline int cow_file_range(struct inode *inode, start + num_bytes - 1, 0); while (disk_num_bytes > 0) { - unsigned long op; - cur_alloc_size = disk_num_bytes; ret = btrfs_reserve_extent(root, cur_alloc_size, cur_alloc_size, fs_info->sectorsize, 0, alloc_hint, &ins, 1, 1); if (ret < 0) goto out_unlock; + cur_alloc_size = ins.offset; + extent_reserved = true; ram_size = ins.offset; em = create_io_em(inode, start, ins.offset, /* len */ @@ -1012,7 +1015,6 @@ static noinline int cow_file_range(struct inode *inode, goto out_reserve; free_extent_map(em); - cur_alloc_size = ins.offset; ret = btrfs_add_ordered_extent(inode, start, ins.objectid, ram_size, cur_alloc_size, 0); if (ret) @@ -1047,14 +1049,14 @@ static noinline int cow_file_range(struct inode *inode, * Do set the Private2 bit so we know this page was properly * setup for writepage */ - op = unlock ? PAGE_UNLOCK : 0; - op |= PAGE_SET_PRIVATE2; + page_ops = unlock ? PAGE_UNLOCK : 0; + page_ops |= PAGE_SET_PRIVATE2; extent_clear_unlock_delalloc(inode, start, start + ram_size - 1, delalloc_end, locked_page, EXTENT_LOCKED | EXTENT_DELALLOC, - op); + page_ops); if (disk_num_bytes > cur_alloc_size) disk_num_bytes = 0; else @@ -1062,6 +1064,7 @@ static noinline int cow_file_range(struct inode *inode, num_bytes -= cur_alloc_size; alloc_hint = ins.objectid + ins.offset; start += cur_alloc_size; + extent_reserved = false; /* * btrfs_reloc_clone_csums() error, since start is increased @@ -1080,12 +1083,35 @@ static noinline int cow_file_range(struct inode *inode, btrfs_dec_block_group_reservations(fs_info, ins.objectid); btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1); out_unlock: + clear_bits = EXTENT_LOCKED | EXTENT_DO_ACCOUNTING | EXTENT_DELALLOC | + EXTENT_DEFRAG; + page_ops = PAGE_UNLOCK | PAGE_CLEAR_DIRTY | PAGE_SET_WRITEBACK | + PAGE_END_WRITEBACK; + /* + * If we reserved an extent for our delalloc range (or a subrange) and + * failed to create the respective ordered extent, then it means that + * when we reserved the extent we decremented the extent's size from + * the data space_info's bytes_may_use counter and incremented the + * space_info's bytes_reserved counter by the same amount. We must make + * sure extent_clear_unlock_delalloc() does not try to decrement again + * the data space_info's bytes_may_use counter, therefore we pass it the + * flag EXTENT_SPACE_FREED. + */ + if (extent_reserved) { + extent_clear_unlock_delalloc(inode, start, + start + cur_alloc_size, + start + cur_alloc_size, + locked_page, + clear_bits | EXTENT_SPACE_FREED, + page_ops); + start += cur_alloc_size; + if (start >= end) + goto out; + } extent_clear_unlock_delalloc(inode, start, end, delalloc_end, locked_page, - EXTENT_LOCKED | EXTENT_DO_ACCOUNTING | - EXTENT_DELALLOC | EXTENT_DEFRAG, - PAGE_UNLOCK | PAGE_CLEAR_DIRTY | - PAGE_SET_WRITEBACK | PAGE_END_WRITEBACK); + clear_bits, + page_ops); goto out; } @@ -1794,10 +1820,10 @@ static void btrfs_clear_bit_hook(struct btrfs_inode *inode, if (btrfs_is_testing(fs_info)) return; - if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID - && do_list && !(state->state & EXTENT_NORESERVE) - && (*bits & (EXTENT_DO_ACCOUNTING | - EXTENT_CLEAR_DATA_RESV))) + if (root->root_key.objectid != BTRFS_DATA_RELOC_TREE_OBJECTID && + do_list && !(state->state & EXTENT_NORESERVE) && + (*bits & (EXTENT_DO_ACCOUNTING | EXTENT_CLEAR_DATA_RESV)) && + !(*bits & EXTENT_SPACE_FREED)) btrfs_free_reserved_data_space_noquota( &inode->vfs_inode, state->start, len);