On 2019/8/27 10:01, Chao Yu wrote:
> On 2019/8/21 12:48, Shin'ichiro Kawasaki wrote:
>> On sudden f2fs shutdown, zoned block device status and f2fs current
>> segment positions in meta data can be inconsistent. When f2fs shutdown
>> happens before write operations completes, 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, the
>> inconsistency causes write operations not at write pointers and
>> "Unaligned write command" error is reported. This error was observed when
>> xfstests test case generic/388 was run with f2fs on a zoned block device.
>>
>> To avoid the error, have f2fs.fsck check consistency between each current
>> segment's position and the write pointer of the zone the current segment
>> points to. If the write pointer goes advance from the current segment,
>> fix the current segment position setting at same as the write pointer
>> position. In case the write pointer is behind the current segment, write
>> zero data at the write pointer position to make write pointer position at
>> same as the current segment.
>>
>> When inconsistencies are found, turn on c.bug_on flag in fsck_verify() to
>> ask users to fix them or not. When inconsistencies get fixed, turn on
>> 'force' flag in fsck_verify() to enforce fixes in following checks. This
>> position fix is done at the beginning of do_fsck() function so that other
>> checks reflect the current segment modification.
>>
>> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawas...@wdc.com>
>> ---
>>  fsck/fsck.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>>  fsck/fsck.h |   3 ++
>>  fsck/main.c |   2 +
>>  3 files changed, 138 insertions(+)
>>
>> diff --git a/fsck/fsck.c b/fsck/fsck.c
>> index 8953ca1..21a06ac 100644
>> --- a/fsck/fsck.c
>> +++ b/fsck/fsck.c
>> @@ -2574,6 +2574,125 @@ out:
>>      return cnt;
>>  }
>>  
>> +struct write_pointer_check_data {
>> +    struct f2fs_sb_info *sbi;
>> +    struct device_info *dev;
>> +};
>> +
>> +#define SECTOR_SHIFT 9
>> +
>> +static int fsck_chk_write_pointer(int i, struct blk_zone *blkz, void 
>> *opaque)
>> +{
>> +    struct write_pointer_check_data *wpd = opaque;
>> +    struct f2fs_sb_info *sbi = wpd->sbi;
>> +    struct device_info *dev = wpd->dev;
>> +    struct f2fs_fsck *fsck = F2FS_FSCK(sbi);
>> +    block_t zone_block, wp_block, wp_blkoff, cs_block, b;
>> +    unsigned int zone_segno, wp_segno;
>> +    struct seg_entry *se;
>> +    struct curseg_info *cs;
>> +    int cs_index, ret;
>> +    int log_sectors_per_block = sbi->log_blocksize - SECTOR_SHIFT;
>> +    unsigned int segs_per_zone = sbi->segs_per_sec * sbi->secs_per_zone;
>> +    void *zero_blk;
>> +
>> +    if (blk_zone_conv(blkz))
>> +            return 0;
>> +
>> +    zone_block = dev->start_blkaddr
>> +            + (blk_zone_sector(blkz) >> log_sectors_per_block);
>> +    zone_segno = GET_SEGNO(sbi, zone_block);
>> +    wp_block = dev->start_blkaddr
>> +            + (blk_zone_wp_sector(blkz) >> log_sectors_per_block);
>> +    wp_segno = GET_SEGNO(sbi, wp_block);
>> +    wp_blkoff = wp_block - START_BLOCK(sbi, wp_segno);
>> +
>> +    /* find the curseg which points to the zone */
>> +    for (cs_index = 0; cs_index < NO_CHECK_TYPE; cs_index++) {
>> +            cs = &SM_I(sbi)->curseg_array[cs_index];
>> +            if (zone_segno <= cs->segno &&
>> +                cs->segno < zone_segno + segs_per_zone)
>> +                    break;
>> +    }
> 
> Will this happen?
> 
> - write checkpoint
> - curseg points zone A
> - write large number of data
> - curseg points zone B, write pointer > 0
> - sudden power cut, curseg will be reset to zone A
> 
> zone B's write pointer won't be verified due to curseg points to zone A?

IIUC, we are trying fix such condition in a separated PATCH 4/4.

Reviewed-by: Chao Yu <yuch...@huawei.com>

Thanks


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