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Message-ID: <fc8c38f6-a039-7b63-d25c-966b0d4396d8@huawei.com>
Date: Tue, 27 Nov 2018 09:42:39 +0800
From: Chao Yu <yuchao0@...wei.com>
To: Jaegeuk Kim <jaegeuk@...nel.org>,
Sahitya Tummala <stummala@...eaurora.org>
CC: <linux-f2fs-devel@...ts.sourceforge.net>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] f2fs: fix sbi->extent_list corruption issue
On 2018/11/27 8:30, Jaegeuk Kim wrote:
> On 11/26, 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.
>>
>> Signed-off-by: Sahitya Tummala <stummala@...eaurora.org>
>> ---
>> v2:
>> -call evict_inodes() and f2fs_shrink_extent_tree() to cleanup inodes
>>
>> fs/f2fs/f2fs.h | 1 +
>> fs/f2fs/shrinker.c | 2 +-
>> fs/f2fs/super.c | 13 ++++++++++++-
>> 3 files changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 1e03197..aaee63b 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -3407,6 +3407,7 @@ struct rb_entry *f2fs_lookup_rb_tree_ret(struct rb_root_cached *root,
>> bool f2fs_check_rb_tree_consistence(struct f2fs_sb_info *sbi,
>> struct rb_root_cached *root);
>> unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink);
>> +unsigned long __count_extent_cache(struct f2fs_sb_info *sbi);
>> bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext);
>> void f2fs_drop_extent_tree(struct inode *inode);
>> unsigned int f2fs_destroy_extent_node(struct inode *inode);
>> diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c
>> index 9e13db9..7e3c13b 100644
>> --- a/fs/f2fs/shrinker.c
>> +++ b/fs/f2fs/shrinker.c
>> @@ -30,7 +30,7 @@ static unsigned long __count_free_nids(struct f2fs_sb_info *sbi)
>> return count > 0 ? count : 0;
>> }
>>
>> -static unsigned long __count_extent_cache(struct f2fs_sb_info *sbi)
>> +unsigned long __count_extent_cache(struct f2fs_sb_info *sbi)
>> {
>> return atomic_read(&sbi->total_zombie_tree) +
>> atomic_read(&sbi->total_ext_node);
>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>> index af58b2c..769e7b1 100644
>> --- a/fs/f2fs/super.c
>> +++ b/fs/f2fs/super.c
>> @@ -3016,6 +3016,16 @@ static void f2fs_tuning_parameters(struct f2fs_sb_info *sbi)
>> sbi->readdir_ra = 1;
>> }
>>
>> +static void f2fs_cleanup_inodes(struct f2fs_sb_info *sbi)
>> +{
>> + struct super_block *sb = sbi->sb;
>> +
>> + sync_filesystem(sb);
>
> This writes another checkpoint, which would not be what this retrial intended.
Actually, checkpoint will not be triggered due to SBI_POR_DOING flag check
as below:
int f2fs_sync_fs(struct super_block *sb, int sync)
{
...
if (unlikely(is_sbi_flag_set(sbi, SBI_POR_DOING)))
return -EAGAIN;
...
}
And also all dirty data/node won't be persisted due to SBI_POR_DOING flag,
IIUC.
Thanks,
> How about adding a condition in f2fs_may_extent_tree() when adding extents?
> Likewise, if (shrinker is not registered) return false;
>
>
>> + shrink_dcache_sb(sb);
>> + evict_inodes(sb);
>> + f2fs_shrink_extent_tree(sbi, __count_extent_cache(sbi));
>> +}
>> +
>> static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>> {
>> struct f2fs_sb_info *sbi;
>> @@ -3402,6 +3412,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>> * falls into an infinite loop in f2fs_sync_meta_pages().
>> */
>> truncate_inode_pages_final(META_MAPPING(sbi));
>> + /* cleanup recovery and quota inodes */
>> + f2fs_cleanup_inodes(sbi);
>> f2fs_unregister_sysfs(sbi);
>> free_root_inode:
>> dput(sb->s_root);
>> @@ -3445,7 +3457,6 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
>> /* give only one another chance */
>> if (retry) {
>> retry = false;
>> - shrink_dcache_sb(sb);
>> goto try_onemore;
>> }
>> return err;
>> --
>> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.
>
> .
>
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