On 2019/11/28 13:31, Shinichiro Kawasaki wrote:
> On Nov 25, 2019 / 15:37, Chao Yu wrote:
>> On 2019/11/14 16:19, Shin'ichiro Kawasaki wrote:
>>> To catch f2fs bugs in write pointer handling code for zoned block
>>> devices, check write pointers of non-open zones that current segments do
>>> not point to. Do this check at mount time, after the fsync data recovery
>>> and current segments' write pointer consistency fix. Or when fsync data
>>> recovery is disabled by mount option, do the check when there is no fsync
>>> data.
>>>
>>> Check two items comparing write pointers with valid block maps in SIT.
>>> The first item is check for zones with no valid blocks. When there is no
>>> valid blocks in a zone, the write pointer should be at the start of the
>>> zone. If not, next write operation to the zone will cause unaligned write
>>> error. If write pointer is not at the zone start, make mount fail and ask
>>> users to run fsck.
>>>
>>> The second item is check between the write pointer position and the last
>>> valid block in the zone. It is unexpected that the last valid block
>>> position is beyond the write pointer. In such a case, report as a bug.
>>> Fix is not required for such zone, because the zone is not selected for
>>> next write operation until the zone get discarded.
>>>
>>> Also move a constant F2FS_REPORT_ZONE from super.c to f2fs.h to use it
>>> in segment.c also.
>>>
>>> Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
>>> ---
>>> fs/f2fs/f2fs.h | 3 +
>>> fs/f2fs/segment.c | 149 ++++++++++++++++++++++++++++++++++++++++++++++
>>> fs/f2fs/super.c | 16 ++++-
>>> 3 files changed, 165 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index a2e24718c13b..1bb64950d793 100644
>>> --- a/fs/f2fs/f2fs.h
>>> +++ b/fs/f2fs/f2fs.h
>>> @@ -3137,6 +3137,7 @@ 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_check_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);
>>> @@ -3610,6 +3611,8 @@ static inline bool f2fs_blkz_is_seq(struct
>>> f2fs_sb_info *sbi, int devi,
>>>
>>> return test_bit(zno, FDEV(devi).blkz_seq);
>>> }
>>> +
>>> +#define F2FS_REPORT_NR_ZONES 4096
>>> #endif
>>>
>>> static inline bool f2fs_hw_should_discard(struct f2fs_sb_info *sbi)
>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>>> index 6ece146dab34..29e3b6f62f8c 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -4333,6 +4333,133 @@ static int sanity_check_curseg(struct f2fs_sb_info
>>> *sbi)
>>>
>>> #ifdef CONFIG_BLK_DEV_ZONED
>>>
>>> +static int check_zone_write_pointer(struct f2fs_sb_info *sbi,
>>> + struct f2fs_dev_info *fdev,
>>> + struct blk_zone *zone)
>>> +{
>>> + unsigned int wp_segno, wp_blkoff, zone_secno, zone_segno, segno;
>>> + block_t zone_block, wp_block, last_valid_block;
>>> + unsigned int log_sectors_per_block = sbi->log_blocksize - SECTOR_SHIFT;
>>> + int i, s, b;
>>> + struct seg_entry *se;
>>> +
>>> + wp_block = fdev->start_blk + (zone->wp >> log_sectors_per_block);
>>> + wp_segno = GET_SEGNO(sbi, wp_block);
>>> + wp_blkoff = wp_block - START_BLOCK(sbi, wp_segno);
>>> + zone_block = fdev->start_blk + (zone->start >> log_sectors_per_block);
>>> + zone_segno = GET_SEGNO(sbi, zone_block);
>>> + zone_secno = GET_SEC_FROM_SEG(sbi, zone_segno);
>>> +
>>> + if (zone_segno >= MAIN_SEGS(sbi))
>>> + return 0;
>>> +
>>> + /*
>>> + * Skip check of zones cursegs point to, since
>>> + * fix_curseg_write_pointer() checks them.
>>> + */
>>> + for (i = 0; i < NO_CHECK_TYPE; i++)
>>> + if (zone_secno == GET_SEC_FROM_SEG(sbi,
>>> + CURSEG_I(sbi, i)->segno))
>>> + return 0;
>>> +
>>> + /*
>>> + * Get last valid block of the zone.
>>> + */
>>> + last_valid_block = zone_block - 1;
>>> + for (s = sbi->segs_per_sec - 1; s >= 0; s--) {
>>> + segno = zone_segno + s;
>>> + se = get_seg_entry(sbi, segno);
>>> + for (b = sbi->blocks_per_seg - 1; b >= 0; b--)
>>> + if (f2fs_test_bit(b, se->cur_valid_map)) {
>>> + last_valid_block = START_BLOCK(sbi, segno) + b;
>>> + break;
>>> + }
>>> + if (last_valid_block >= zone_block)
>>> + break;
>>> + }
>>> +
>>> + /*
>>> + * If last valid block is beyond the write pointer, report the
>>> + * inconsistency. This inconsistency does not cause write error
>>> + * because the zone will not be selected for write operation until
>>> + * it get discarded. Just report it.
>>> + */
>>> + if (last_valid_block >= wp_block) {
>>> + f2fs_notice(sbi, "Valid block beyond write pointer: "
>>> + "valid block[0x%x,0x%x] wp[0x%x,0x%x]",
>>> + GET_SEGNO(sbi, last_valid_block),
>>> + GET_BLKOFF_FROM_SEG0(sbi, last_valid_block),
>>> + wp_segno, wp_blkoff);
>>> + return 0;
>>> + }
>>> +
>>> + /*
>>> + * If there is no valid block in the zone and if write pointer is
>>> + * not at zone start, report the error to run fsck.
>>
>> So we only need to report this as inconsistent status in the condition of
>> discard has been triggered, right? otherwise, f2fs will trigger discard later
>> to reset zone->wp before opening this zone?
>
> Hmm, my intent was to catch the inconsistency at mount time, assuming the
> inconsistency is not expected at mount time. In other words, I assume that
> discard is triggered for zones without valid blocks before that last clean
IIUC, if there is too many pending discards, put_super() may drop discard
entries
to avoid delaying umount, so we can not assume all discards are always being
triggered.
So what I mean is for the condition of a) there is valid (including fsycned)
block,
b) zone->wp is not at correct position, f2fs can handle it by issuing discard.
Let
me know if I misread this comment.
Thanks,
> umount. If the last sudden f2fs shutdown without clean umount caused the
> inconsistency, it should be reported and fixed, I think.
>
> SIT valid blocks are referred to check if there is no valid blocks in the
> zone.
> SIT may be broken due to software bug or hardware flaw, then I think it is the
> better to run fsck rather than discard by f2fs.
>
> If I miss anything, please let me know.
>
> --
> Best Regards,
> Shin'ichiro Kawasaki
>
>>
>> Thanks,
>>
>>> + */
>>> + if (last_valid_block + 1 == zone_block && zone->wp != zone->start) {
>>> + f2fs_notice(sbi,
>>> + "Zone without valid block has non-zero write "
>>> + "pointer, run fsck to fix: wp[0x%x,0x%x]",
>>> + wp_segno, wp_blkoff);
>>> + f2fs_stop_checkpoint(sbi, true);
>>> + set_sbi_flag(sbi, SBI_NEED_FSCK);
>>> + return -EINVAL;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int check_dev_write_pointer(struct f2fs_sb_info *sbi,
>>> + struct f2fs_dev_info *fdev) {
>>> + sector_t nr_sectors = fdev->bdev->bd_part->nr_sects;
>>> + sector_t sector = 0;
>>> + struct blk_zone *zones;
>>> + unsigned int i, nr_zones;
>>> + unsigned int n = 0;
>>> + int err = -EIO;
>>> +
>>> + if (!bdev_is_zoned(fdev->bdev))
>>> + return 0;
>>> +
>>> + zones = f2fs_kzalloc(sbi,
>>> + array_size(F2FS_REPORT_NR_ZONES,
>>> + sizeof(struct blk_zone)),
>>> + GFP_KERNEL);
>>> + if (!zones)
>>> + return -ENOMEM;
>>> +
>>> + /* Get block zones type */
>>> + while (zones && sector < nr_sectors) {
>>> +
>>> + nr_zones = F2FS_REPORT_NR_ZONES;
>>> + err = blkdev_report_zones(fdev->bdev, sector, zones, &nr_zones);
>>> + if (err)
>>> + break;
>>> + if (!nr_zones) {
>>> + err = -EIO;
>>> + break;
>>> + }
>>> +
>>> + for (i = 0; i < nr_zones; i++) {
>>> + if (zones[i].type == BLK_ZONE_TYPE_SEQWRITE_REQ) {
>>> + err = check_zone_write_pointer(sbi, fdev,
>>> + &zones[i]);
>>> + if (err)
>>> + break;
>>> + }
>>> + sector += zones[i].len;
>>> + n++;
>>> + }
>>> + if (err)
>>> + break;
>>> + }
>>> +
>>> + kvfree(zones);
>>> +
>>> + return err;
>>> +}
>>> +
>>> static struct f2fs_dev_info *get_target_zoned_dev(struct f2fs_sb_info *sbi,
>>> block_t zone_blkaddr)
>>> {
>>> @@ -4399,6 +4526,10 @@ static int fix_curseg_write_pointer(struct
>>> f2fs_sb_info *sbi, int type)
>>> "curseg[0x%x,0x%x]", type, cs->segno, cs->next_blkoff);
>>> allocate_segment_by_default(sbi, type, true);
>>>
>>> + /* check consistency of the zone curseg pointed to */
>>> + if (check_zone_write_pointer(sbi, zbd, &zone))
>>> + return -EIO;
>>> +
>>> /* 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));
>>> @@ -4444,11 +4575,29 @@ int f2fs_fix_curseg_write_pointer(struct
>>> f2fs_sb_info *sbi)
>>>
>>> return 0;
>>> }
>>> +
>>> +int f2fs_check_write_pointer(struct f2fs_sb_info *sbi)
>>> +{
>>> + int i, ret;
>>> +
>>> + for (i = 0; i < sbi->s_ndevs; i++) {
>>> + ret = check_dev_write_pointer(sbi, &FDEV(i));
>>> + if (ret)
>>> + return ret;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> #else
>>> int f2fs_fix_curseg_write_pointer(struct f2fs_sb_info *sbi)
>>> {
>>> return 0;
>>> }
>>> +
>>> +int f2fs_check_write_pointer(struct f2fs_sb_info *sbi)
>>> +{
>>> + return 0;
>>> +}
>>> #endif
>>>
>>> /*
>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>> index 1443cee15863..8ca772670c67 100644
>>> --- a/fs/f2fs/super.c
>>> +++ b/fs/f2fs/super.c
>>> @@ -2890,8 +2890,6 @@ static int init_blkz_info(struct f2fs_sb_info *sbi,
>>> int devi)
>>> if (!FDEV(devi).blkz_seq)
>>> return -ENOMEM;
>>>
>>> -#define F2FS_REPORT_NR_ZONES 4096
>>> -
>>> zones = f2fs_kzalloc(sbi,
>>> array_size(F2FS_REPORT_NR_ZONES,
>>> sizeof(struct blk_zone)),
>>> @@ -3509,7 +3507,8 @@ static int f2fs_fill_super(struct super_block *sb,
>>> void *data, int silent)
>>>
>>> err = f2fs_recover_fsync_data(sbi, false);
>>> if (err < 0) {
>>> - if (err != -ENOMEM)
>>> + if (err != -ENOMEM &&
>>> + !is_sbi_flag_set(sbi, SBI_NEED_FSCK))
>>> skip_recovery = true;
>>> need_fsck = true;
>>> f2fs_err(sbi, "Cannot recover all fsync data errno=%d",
>>> @@ -3525,6 +3524,17 @@ static int f2fs_fill_super(struct super_block *sb,
>>> void *data, int silent)
>>> goto free_meta;
>>> }
>>> }
>>> +
>>> + /*
>>> + * If the f2fs is not readonly and fsync data recovery succeeds,
>>> + * check zoned block devices' write pointer consistency.
>>> + */
>>> + if (!err && !f2fs_readonly(sb) && f2fs_sb_has_blkzoned(sbi)) {
>>> + err = f2fs_check_write_pointer(sbi);
>>> + if (err)
>>> + goto free_meta;
>>> + }
>>> +
>>> reset_checkpoint:
>>> /* f2fs_recover_fsync_data() cleared this already */
>>> clear_sbi_flag(sbi, SBI_POR_DOING);
>>> .
>
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