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

[Chao Yu <yuchao0@huawei.com>]

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)

> +	    && 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.

Thanks,

> +		return 0;
> +
> +	f2fs_notice(sbi, "Unaligned curseg[%d] with write pointer: "
> +		    "curseg[0x%x,0x%x] wp[0x%x,0x%x]",
> +		    type, cs->segno, cs->next_blkoff, wp_segno, wp_blkoff);
> +
> +	f2fs_notice(sbi, "Assign new section to curseg[%d]: "
> +		    "curseg[0x%x,0x%x]", type, cs->segno, cs->next_blkoff);
> +	allocate_segment_by_default(sbi, type, true);
> +
> +	/* check newly assigned zone */
> +	cs_section = GET_SEC_FROM_SEG(sbi, cs->segno);
> +	cs_zone_block = START_BLOCK(sbi, GET_SEG_FROM_SEC(sbi, cs_section));
> +
> +	zbd = get_target_zoned_dev(sbi, cs_zone_block);
> +	if (!zbd)
> +		return 0;
> +
> +	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;
> +
> +	if (zone.wp != zone.start) {
> +		f2fs_notice(sbi,
> +			    "New section for curseg[%d] is not empty, "
> +			    "run fsck to fix: curseg[0x%x,0x%x]",
> +			    type, cs->segno, cs->next_blkoff);
> +		set_sbi_flag(sbi, SBI_NEED_FSCK);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +int f2fs_fix_curseg_write_pointer(struct f2fs_sb_info *sbi)
> +{
> +	int i, ret;
> +
> +	for (i = 0; i < NO_CHECK_TYPE; i++) {
> +		ret = fix_curseg_write_pointer(sbi, i);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +#else
> +int f2fs_fix_curseg_write_pointer(struct f2fs_sb_info *sbi)
> +{
> +	return 0;
> +}
> +#endif
> +
>  /*
>   * Update min, max modified time for cost-benefit GC algorithm
>   */
> 


_______________________________________________
Linux-f2fs-devel mailing list
Linux-f2fs-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel