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Date: Wed, 9 Jan 2019 14:13:02 +0800
From: Chao Yu <yuchao0@...wei.com>
To: Jaegeuk Kim <jaegeuk@...nel.org>
CC: Sahitya Tummala <stummala@...eaurora.org>,
<linux-f2fs-devel@...ts.sourceforge.net>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] f2fs: fix sbi->extent_list corruption issue
On 2019/1/9 12:38, Jaegeuk Kim wrote:
> On 01/07, Chao Yu wrote:
>> On 2019/1/5 4:33, Jaegeuk Kim wrote:
>>> On 01/04, Sahitya Tummala wrote:
>>>> On Mon, Nov 26, 2018 at 10:17:20AM +0530, Sahitya Tummala wrote:
>>>>> When there is a failure in f2fs_fill_super() after/during
>>>>> the recovery of fsync'd nodes, it frees the current sbi and
>>>>> retries again. This time the mount is successful, but the files
>>>>> that got recovered before retry, still holds the extent tree,
>>>>> whose extent nodes list is corrupted since sbi and sbi->extent_list
>>>>> is freed up. The list_del corruption issue is observed when the
>>>>> file system is getting unmounted and when those recoverd files extent
>>>>> node is being freed up in the below context.
>>>>>
>>>>> list_del corruption. prev->next should be fffffff1e1ef5480, but was (null)
>>>>> <...>
>>>>> kernel BUG at kernel/msm-4.14/lib/list_debug.c:53!
>>>>> task: fffffff1f46f2280 task.stack: ffffff8008068000
>>>>> lr : __list_del_entry_valid+0x94/0xb4
>>>>> pc : __list_del_entry_valid+0x94/0xb4
>>>>> <...>
>>>>> Call trace:
>>>>> __list_del_entry_valid+0x94/0xb4
>>>>> __release_extent_node+0xb0/0x114
>>>>> __free_extent_tree+0x58/0x7c
>>>>> f2fs_shrink_extent_tree+0xdc/0x3b0
>>>>> f2fs_leave_shrinker+0x28/0x7c
>>>>> f2fs_put_super+0xfc/0x1e0
>>>>> generic_shutdown_super+0x70/0xf4
>>>>> kill_block_super+0x2c/0x5c
>>>>> kill_f2fs_super+0x44/0x50
>>>>> deactivate_locked_super+0x60/0x8c
>>>>> deactivate_super+0x68/0x74
>>>>> cleanup_mnt+0x40/0x78
>>>>> __cleanup_mnt+0x1c/0x28
>>>>> task_work_run+0x48/0xd0
>>>>> do_notify_resume+0x678/0xe98
>>>>> work_pending+0x8/0x14
>>>>>
>>>>> Fix this by cleaning up inodes, extent tree and nodes of those
>>>>> recovered files before freeing up sbi and before next retry.
>>>>>
>>>> Hi Jaegeuk, Chao,
>>>>
>>>> I have observed another scenario where the similar list corruption issue
>>>> can happen with sbi->inode_list as well. If recover_fsync_data()
>>>> fails at some point in write_checkpoint() due to some error and if
>>>> those recovered inodes are still dirty, then after the mount is
>>>> successful, this issue is observed when that dirty inode is under
>>>> writeback.
>>>
>>> recover_fsync_data() does iget/iput in pair, and destroy_fsync_dnodes() drops
>>> its dirty list and call iput(), when there is an error. So, after then, there'd
>>> be no dirty inodes. If there's no error, checkpoint() flushes quota/dentry pages
>>> in dirty inodes as well. Can we check where this dirty inode came from?
>>
>> I guess it comes from:
>>
>> f2fs_recover_fsync_data()
>>
>> /* Needed for iput() to work correctly and not trash data */
>> sbi->sb->s_flags |= SB_ACTIVE;
>>
>> iput_final()
>>
>> if (!drop && (sb->s_flags & SB_ACTIVE)) {
>> inode_add_lru(inode);
>> spin_unlock(&inode->i_lock);
>> return;
>> }
>>
>> So dirty data in those inode can be remained after iput(), then meta/node
>> can be persisted during next checkpoint, if checkpoint failed due to error,
>> dirty inode remain in system. IIUC.
>
>
> 749 err = recover_data(sbi, &inode_list, &tmp_inode_list, &dir_list);
> 750 if (!err)
> 751 f2fs_bug_on(sbi, !list_empty(&inode_list));
> 752 else {
> 753 /* restore s_flags to let iput() trash data */
> 754 sbi->sb->s_flags = s_flags;
> 755 }
>
> We deactivate sb before iput?
We only restore s_flags in error path of recover_data? I remember Sahitya
said his case is encountering error in later checkpoint()?
Thanks,
>
>>
>>>
>>> Oh, one sceanrio can be an error by f2fs_disable_checkpoint() which will do GC.
>>>
>>>>
>>>> [ 90.400500] list_del corruption. prev->next should be ffffffed1f566208, but was (null)
>>>> [ 90.675349] Call trace:
>>>> [ 90.677869] __list_del_entry_valid+0x94/0xb4
>>>> [ 90.682351] remove_dirty_inode+0xac/0x114
>>>> [ 90.686563] __f2fs_write_data_pages+0x6a8/0x6c8
>>>> [ 90.691302] f2fs_write_data_pages+0x40/0x4c
>>>> [ 90.695695] do_writepages+0x80/0xf0
>>>> [ 90.699372] __writeback_single_inode+0xdc/0x4ac
>>>> [ 90.704113] writeback_sb_inodes+0x280/0x440
>>>> [ 90.708501] wb_writeback+0x1b8/0x3d0
>>>> [ 90.712267] wb_workfn+0x1a8/0x4d4
>>>> [ 90.715765] process_one_work+0x1c0/0x3d4
>>>> [ 90.719883] worker_thread+0x224/0x344
>>>> [ 90.723739] kthread+0x120/0x130
>>>> [ 90.727055] ret_from_fork+0x10/0x18
>>>>
>>>> I think it is better to cleanup those inodes completely before freeing sbi
>>>> and before next retry as done in this patch. Would you like to re-consider
>>>> this patch for this new issue?
>>>
>>> The patch was merged in mainline already.
>>> Could you take a look at this patch?
>>>
>>> >From cb1d20e640402beed300c2bdce79311ee8a781ad Mon Sep 17 00:00:00 2001
>>> From: Jaegeuk Kim <jaegeuk@...nel.org>
>>> Date: Fri, 4 Jan 2019 12:29:00 -0800
>>> Subject: [PATCH] f2fs: sync filesystem after roll-forward recovery
>>
>> You mean android kernel mainline?
>
> I meant the previous patch was upstreamed. We need another patch to address this
> second issue.
>
> Thanks,
>
>>
>> Thanks,
>>
>>>
>>> Some works after roll-forward recovery can get an error which will release
>>> all the data structures. Let's flush them in order to make it clean.
>>>
>>> One possible corruption came from:
>>>
>>> [ 90.400500] list_del corruption. prev->next should be ffffffed1f566208, but was (null)
>>> [ 90.675349] Call trace:
>>> [ 90.677869] __list_del_entry_valid+0x94/0xb4
>>> [ 90.682351] remove_dirty_inode+0xac/0x114
>>> [ 90.686563] __f2fs_write_data_pages+0x6a8/0x6c8
>>> [ 90.691302] f2fs_write_data_pages+0x40/0x4c
>>> [ 90.695695] do_writepages+0x80/0xf0
>>> [ 90.699372] __writeback_single_inode+0xdc/0x4ac
>>> [ 90.704113] writeback_sb_inodes+0x280/0x440
>>> [ 90.708501] wb_writeback+0x1b8/0x3d0
>>> [ 90.712267] wb_workfn+0x1a8/0x4d4
>>> [ 90.715765] process_one_work+0x1c0/0x3d4
>>> [ 90.719883] worker_thread+0x224/0x344
>>> [ 90.723739] kthread+0x120/0x130
>>> [ 90.727055] ret_from_fork+0x10/0x18
>>>
>>> Reported-by: Sahitya Tummala <stummala@...eaurora.org>
>>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>>> ---
>>> fs/f2fs/super.c | 8 ++++++--
>>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index 547cb7459be7..bb02186293a3 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -3357,7 +3357,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>>> if (test_opt(sbi, DISABLE_CHECKPOINT)) {
>>> err = f2fs_disable_checkpoint(sbi);
>>> if (err)
>>> - goto free_meta;
>>> + goto sync_free_meta;
>>> } else if (is_set_ckpt_flags(sbi, CP_DISABLED_FLAG)) {
>>> f2fs_enable_checkpoint(sbi);
>>> }
>>> @@ -3370,7 +3370,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>>> /* After POR, we can run background GC thread.*/
>>> err = f2fs_start_gc_thread(sbi);
>>> if (err)
>>> - goto free_meta;
>>> + goto sync_free_meta;
>>> }
>>> kvfree(options);
>>>
>>> @@ -3392,6 +3392,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>>> f2fs_update_time(sbi, REQ_TIME);
>>> return 0;
>>>
>>> +sync_free_meta:
>>> + /* safe to flush all the data */
>>> + sync_filesystem(sbi->sb);
>>> +
>>> free_meta:
>>> /* flush dirty orphan inode objects */
>>> f2fs_sync_inode_meta(sbi);
>>>
>
> .
>
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