Re: [f2fs-dev] [PATCH v3 1/2] f2fs: Check write pointer consistency of open zones

[Chao Yu <yuchao0@huawei.com>]

On 2019/11/28 12:07, Shinichiro Kawasaki wrote:
> On Nov 25, 2019 / 14:59, Chao Yu wrote:
>> On 2019/11/14 16:19, Shin'ichiro Kawasaki wrote:
>>> On sudden f2fs shutdown, write pointers of zoned block devices can go
>>> further but f2fs meta data keeps current segments at positions before the
>>> write operations. After remounting the f2fs, this inconsistency causes
>>> write operations not at write pointers and "Unaligned write command"
>>> error is reported.
>>>
>>> To avoid the error, compare current segments with write pointers of open
>>> zones the current segments point to, during mount operation. If the write
>>> pointer position is not aligned with the current segment position, assign
>>> a new zone to the current segment. Also check the newly assigned zone has
>>> write pointer at zone start. If not, make mount fail and ask users to run
>>> fsck.
>>>
>>> Perform the consistency check during fsync recovery. Not to lose the
>>> fsync data, do the check after fsync data gets restored and before
>>> checkpoint commit which flushes data at current segment positions. Not to
>>> cause conflict with kworker's dirfy data/node flush, do the fix within
>>> SBI_POR_DOING protection.
>>>
>>> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
>>> ---
>>>  fs/f2fs/f2fs.h     |   1 +
>>>  fs/f2fs/recovery.c |  17 ++++++-
>>>  fs/f2fs/segment.c  | 120 +++++++++++++++++++++++++++++++++++++++++++++
>>>  3 files changed, 136 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index 4024790028aa..a2e24718c13b 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -3136,6 +3136,7 @@ void f2fs_write_node_summaries(struct f2fs_sb_info *sbi, block_t start_blk);
>>>  int f2fs_lookup_journal_in_cursum(struct f2fs_journal *journal, int type,
>>>  			unsigned int val, int alloc);
>>>  void f2fs_flush_sit_entries(struct f2fs_sb_info *sbi, struct cp_control *cpc);
>>> +int f2fs_fix_curseg_write_pointer(struct f2fs_sb_info *sbi);
>>>  int f2fs_build_segment_manager(struct f2fs_sb_info *sbi);
>>>  void f2fs_destroy_segment_manager(struct f2fs_sb_info *sbi);
>>>  int __init f2fs_create_segment_manager_caches(void);
>>> diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
>>> index 783773e4560d..712054ed8d64 100644
>>> --- a/fs/f2fs/recovery.c
>>> +++ b/fs/f2fs/recovery.c
>>> @@ -784,9 +784,22 @@ int f2fs_recover_fsync_data(struct f2fs_sb_info *sbi, bool check_only)
>>>  	if (err) {
>>>  		truncate_inode_pages_final(NODE_MAPPING(sbi));
>>>  		truncate_inode_pages_final(META_MAPPING(sbi));
>>> -	} else {
>>> -		clear_sbi_flag(sbi, SBI_POR_DOING);
>>>  	}
>>> +
>>> +	/*
>>> +	 * If fsync data succeeds or there is no fsync data to recover,
>>> +	 * and the f2fs is not read only, check and fix zoned block devices'
>>> +	 * write pointer consistency.
>>> +	 */
>>> +	if (!ret && !err && !f2fs_readonly(sbi->sb)
>>
>> Using !check_only will be more readable?
>>
>> if (!err && !check_only && !f2fs_readonly(sbi->sb)
> 
> When check_only is on and there is no fsync data, I think we should fix the
> write pointer inconsistency. With the condition you suggested, this case can
> not be covered.

Alright.

> 
> Having said that, my expression with !ret is not good from readability point
> of view. How about this?
> 
> 
> bool fix_curseg_write_pointer;
> fix_curseg_write_pointer = !check_only || (check_only && list_empty(&inode_list));

fix_curseg_write_pointer = !check_only || list_empty(&inode_list); is enough.

> 
> ...
> 
> if (!err && fix_curseg_write_pointer && !f2fs_readonly(sbi->sb)
> 	&& f2fs_sb_has_blkzoned(sbi)) {
> 	err = f2fs_fix_curseg_write_pointer(sbi);
> 	ret = err;
> }

It's okay to me.

Thanks,

> 
> 
>>> +	    && f2fs_sb_has_blkzoned(sbi)) {
>>> +		err = f2fs_fix_curseg_write_pointer(sbi);
>>> +		ret = err;
>>> +	}
>>> +
>>> +	if (!err)
>>> +		clear_sbi_flag(sbi, SBI_POR_DOING);
>>> +
>>>  	mutex_unlock(&sbi->cp_mutex);
>>>  
>>>  	/* let's drop all the directory inodes for clean checkpoint */
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 808709581481..6ece146dab34 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -4331,6 +4331,126 @@ static int sanity_check_curseg(struct f2fs_sb_info *sbi)
>>>  	return 0;
>>>  }
>>>  
>>> +#ifdef CONFIG_BLK_DEV_ZONED
>>> +
>>> +static struct f2fs_dev_info *get_target_zoned_dev(struct f2fs_sb_info *sbi,
>>> +						  block_t zone_blkaddr)
>>> +{
>>> +	int i;
>>> +
>>> +	for (i = 0; i < sbi->s_ndevs; i++) {
>>> +		if (!bdev_is_zoned(FDEV(i).bdev))
>>> +			continue;
>>> +		if (sbi->s_ndevs == 1 || (FDEV(i).start_blk <= zone_blkaddr &&
>>> +					  zone_blkaddr <= FDEV(i).end_blk))
>>> +			return &FDEV(i);
>>> +	}
>>> +
>>> +	return NULL;
>>> +}
>>> +
>>> +static int fix_curseg_write_pointer(struct f2fs_sb_info *sbi, int type)
>>> +{
>>> +	struct curseg_info *cs = CURSEG_I(sbi, type);
>>> +	struct f2fs_dev_info *zbd;
>>> +	struct blk_zone zone;
>>> +	unsigned int cs_section, wp_segno, wp_blkoff, nr_zones, wp_sector_off;
>>> +	block_t cs_zone_block, wp_block, cs_block;
>>> +	unsigned int log_sectors_per_block = sbi->log_blocksize - SECTOR_SHIFT;
>>> +	sector_t zone_sector;
>>> +	int err;
>>> +
>>> +	cs_section = GET_SEC_FROM_SEG(sbi, cs->segno);
>>> +	cs_zone_block = START_BLOCK(sbi, GET_SEG_FROM_SEC(sbi, cs_section));
>>> +	cs_block = START_BLOCK(sbi, cs->segno) + cs->next_blkoff;
>>> +
>>> +	zbd = get_target_zoned_dev(sbi, cs_zone_block);
>>> +	if (!zbd)
>>> +		return 0;
>>> +
>>> +	/* report zone for the sector the curseg points to */
>>> +	zone_sector = (sector_t)(cs_zone_block - zbd->start_blk)
>>> +		<< log_sectors_per_block;
>>> +	nr_zones = 1;
>>> +	err = blkdev_report_zones(zbd->bdev, zone_sector, &zone, &nr_zones);
>>> +	if (err) {
>>> +		f2fs_err(sbi, "Report zone failed: %s errno=(%d)",
>>> +			 zbd->path, err);
>>> +		return err;
>>> +	}
>>> +
>>> +	if (zone.type != BLK_ZONE_TYPE_SEQWRITE_REQ)
>>> +		return 0;
>>> +
>>> +	wp_block = zbd->start_blk + (zone.wp >> log_sectors_per_block);
>>> +	wp_segno = GET_SEGNO(sbi, wp_block);
>>> +	wp_blkoff = wp_block - START_BLOCK(sbi, wp_segno);
>>> +	wp_sector_off = zone.wp & GENMASK(log_sectors_per_block - 1, 0);
>>> +
>>> +	if (cs->segno == wp_segno && cs->next_blkoff == wp_blkoff &&
>>> +	    wp_sector_off == 0)
>>
>> We uses indent instead of space in f2fs coding style, please keep line
>> with it.
> 
> Noted this f2fs conding style. Will replace the spaces with tab indent.
> Thanks!
> 
> --
> Best Regards,
> Shin'ichiro Kawasaki.
> 


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