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Subject: Re: [f2fs-dev] [PATCH] f2fs: avoid frequent costly fsck triggers
To:     Jaegeuk Kim <jaegeuk@kernel.org>
CC:     <linux-kernel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>
References: <20181128073125.39102-1-jaegeuk@kernel.org>
 <724de929-6ee1-3ad7-cfa7-6e80d4e7a3da@huawei.com>
 <20181128081035.GA41969@jaegeuk-macbookpro.roam.corp.google.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <4f43735a-d01f-f194-18ce-4fbbe10ad8d4@huawei.com>
Date:   Wed, 28 Nov 2018 16:19:00 +0800
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On 2018/11/28 16:10, Jaegeuk Kim wrote:
> On 11/28, Chao Yu wrote:
>> Hi Jaeguek,
>>
>> On 2018/11/28 15:31, Jaegeuk Kim wrote:
>>> If we want to re-enable nat_bits, we rely on fsck which requires full scan
>>> of directory tree. Let's do that by regular fsck or unclean shutdown.
>>
>> Reviewed-by: Chao Yu <yuchao0@huawei.com>
>>
>> BTW, I have patch made some month ago...
>>
>> In order to detect nat_bits disabling, could we introduce one more flag for
>> fsck?
> 
> Do we have a way to enable nat_bits very quickly in fsck?

For image with SBI_NATBIT_NEED_REPAIR flag, can we just check metadata and
rebuild nat_bits based on verified nat blocks/journals?

Thanks,

> 
>>
>> >From 86e8bdb2faeec904944bb6621073f4f7de51cc2d Mon Sep 17 00:00:00 2001
>> From: Chao Yu <yuchao0@huawei.com>
>> Date: Sun, 9 Sep 2018 05:40:20 +0800
>> Subject: [PATCH] f2fs: set specified flag after invalidating nat_bits
>>
>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>> ---
>>  fs/f2fs/checkpoint.c    | 12 +++++++++++-
>>  fs/f2fs/f2fs.h          |  3 ++-
>>  fs/f2fs/node.c          |  3 +++
>>  include/linux/f2fs_fs.h |  1 +
>>  4 files changed, 17 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>> index 7e17bb3dfcb1..f7fb14e0f5f9 100644
>> --- a/fs/f2fs/checkpoint.c
>> +++ b/fs/f2fs/checkpoint.c
>> @@ -1226,13 +1226,16 @@ static void update_ckpt_flags(struct f2fs_sb_info
>> *sbi, struct cp_control *cpc)
>>  	unsigned long orphan_num = sbi->im[ORPHAN_INO].ino_num;
>>  	struct f2fs_checkpoint *ckpt = F2FS_CKPT(sbi);
>>  	unsigned long flags;
>> +	bool disable_natbits = false;
>>
>>  	spin_lock_irqsave(&sbi->cp_lock, flags);
>>
>>  	if ((cpc->reason & CP_UMOUNT) &&
>>  			le32_to_cpu(ckpt->cp_pack_total_block_count) >
>> -			sbi->blocks_per_seg - NM_I(sbi)->nat_bits_blocks)
>> +			sbi->blocks_per_seg - NM_I(sbi)->nat_bits_blocks) {
>>  		disable_nat_bits(sbi, false);
>> +		disable_natbits = true;
>> +	}
>>
>>  	if (cpc->reason & CP_TRIMMED)
>>  		__set_ckpt_flags(ckpt, CP_TRIMMED_FLAG);
>> @@ -1270,11 +1273,18 @@ static void update_ckpt_flags(struct f2fs_sb_info
>> *sbi, struct cp_control *cpc)
>>  	if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR))
>>  		__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);
>>
>> +	if (is_sbi_flag_set(sbi, SBI_NATBIT_NEED_REPAIR))
>> +		__set_ckpt_flags(ckpt, CP_NATBIT_NEED_FSCK_FLAG);
>> +
>>  	/* set this flag to activate crc|cp_ver for recovery */
>>  	__set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG);
>>  	__clear_ckpt_flags(ckpt, CP_NOCRC_RECOVERY_FLAG);
>>
>>  	spin_unlock_irqrestore(&sbi->cp_lock, flags);
>> +
>> +	if (disable_natbits)
>> +		f2fs_msg(sbi->sb, KERN_NOTICE,
>> +			"No enough space in CP area, disable nat_bits.");
>>  }
>>
>>  static void commit_checkpoint(struct f2fs_sb_info *sbi,
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index f0cedbe0c536..b55341c269b2 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -1107,6 +1107,7 @@ enum {
>>  	SBI_QUOTA_NEED_FLUSH,			/* need to flush quota info in CP */
>>  	SBI_QUOTA_SKIP_FLUSH,			/* skip flushing quota in current CP */
>>  	SBI_QUOTA_NEED_REPAIR,			/* quota file may be corrupted */
>> +	SBI_NATBIT_NEED_REPAIR,			/* nat full/empty bitmaps need repair */
>>  };
>>
>>  enum {
>> @@ -1628,7 +1629,7 @@ static inline void disable_nat_bits(struct
>> f2fs_sb_info *sbi, bool lock)
>>  {
>>  	unsigned long flags;
>>
>> -	set_sbi_flag(sbi, SBI_NEED_FSCK);
>> +	set_sbi_flag(sbi, SBI_NATBIT_NEED_REPAIR);
>>
>>  	if (lock)
>>  		spin_lock_irqsave(&sbi->cp_lock, flags);
>> diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
>> index e57add1e8966..0c6f8312a087 100644
>> --- a/fs/f2fs/node.c
>> +++ b/fs/f2fs/node.c
>> @@ -2902,6 +2902,9 @@ static int __get_nat_bitmaps(struct f2fs_sb_info *sbi)
>>
>>  	cp_ver |= (cur_cp_crc(ckpt) << 32);
>>  	if (cpu_to_le64(cp_ver) != *(__le64 *)nm_i->nat_bits) {
>> +		f2fs_msg(sbi->sb, KERN_NOTICE,
>> +			"Disable nat_bits due to incorrect cp_ver (%llu, %llu)",
>> +			cp_ver, le64_to_cpu(*(__le64 *)nm_i->nat_bits));
>>  		disable_nat_bits(sbi, true);
>>  		return 0;
>>  	}
>> diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
>> index 7196653833fa..1f3ae1504573 100644
>> --- a/include/linux/f2fs_fs.h
>> +++ b/include/linux/f2fs_fs.h
>> @@ -117,6 +117,7 @@ struct f2fs_super_block {
>>  /*
>>   * For checkpoint
>>   */
>> +#define CP_NATBIT_NEED_FSCK_FLAG	0X00002000
>>  #define CP_DISABLED_FLAG		0x00001000
>>  #define CP_QUOTA_NEED_FSCK_FLAG		0x00000800
>>  #define CP_LARGE_NAT_BITMAP_FLAG	0x00000400
>> -- 
>> 2.18.0.rc1
>>
>>
>>
>>>
>>> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
>>> ---
>>>  fs/f2fs/f2fs.h | 6 +++++-
>>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index c28a9d1cb278..aa500239baf2 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -1621,7 +1621,11 @@ static inline void disable_nat_bits(struct f2fs_sb_info *sbi, bool lock)
>>>  {
>>>  	unsigned long flags;
>>>  
>>> -	set_sbi_flag(sbi, SBI_NEED_FSCK);
>>> +	/*
>>> +	 * In order to re-enable nat_bits we need to call fsck.f2fs by
>>> +	 * set_sbi_flag(sbi, SBI_NEED_FSCK). But it may give huge cost,
>>> +	 * so let's rely on regular fsck or unclean shutdown.
>>> +	 */
>>>  
>>>  	if (lock)
>>>  		spin_lock_irqsave(&sbi->cp_lock, flags);
>>>
> 
> .
>