On 2019/11/8 12:27, Shinichiro Kawasaki wrote:
> On Nov 05, 2019 / 20:22, Chao Yu wrote:
>> On 2019/10/28 14:58, 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. 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 the 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 | 147 ++++++++++++++++++++++++++++++++++++++++++++++
>>> fs/f2fs/super.c | 11 ++--
>>> 3 files changed, 157 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>>> index 0216282c5b80..e8524be17852 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, bool
>>> check_only);
>>> +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 2b6e637dd6d3..20ef5b3705e1 100644
>>> --- a/fs/f2fs/segment.c
>>> +++ b/fs/f2fs/segment.c
>>> @@ -4333,6 +4333,131 @@ 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 s, wp_segno, wp_blkoff, zone_secno, zone_segno, segno;
>>> + block_t zone_block, wp_block, last_valid_block, b;
>>> + unsigned int log_sectors_per_block = sbi->log_blocksize - SECTOR_SHIFT;
>>> + int i;
>>> + 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;
>>> +
>>> + /*
>>> + * If a curseg points to the zone, skip check because the zone
>>> + * may have fsync data that valid block map does not mark.
>>
>> None-curseg zone may also contain fsynced data as well? Maybe we can only
>> verify
>> on clean image or recovered image?
>
> Right. This function for none-curseg zones should be called after fsync data
If so, any place to check recovery is done? You know, user can choose to skip
recovery by using disable_roll_forward/norecovery mount option.
> recovery. I think my comment above is confusing. The point is that this
> function is for none-curseg zones, and other function covers check for curseg
> zones. Let me revise the comment as follows:
>
> 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 = 0; s < sbi->segs_per_sec; s++) {
>>> + segno = zone_segno + s;
>>> + se = get_seg_entry(sbi, segno);
>>> + for (b = 0; b < sbi->blocks_per_seg; b++)
>>> + if (f2fs_test_bit(b, se->cur_valid_map))
>>> + last_valid_block = START_BLOCK(sbi, segno) + b;
>>> + }
>>
>> We search bitmap table reversedly.
>
> Yes, will reverse the loops in the next post.
>
>>
>>> +
>>> + /*
>>> + * 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 and mark the
>>> + * zone as used.
>>> + */
>>> + 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);
>>> + __set_inuse(sbi, zone_segno);
>>
>> Why do we need to set it inused? if this is necessary, we need to call this
>> under free_i->segmap_lock.
>
> I once thought that I need to set inconsistent zones in use, because I
> observed
> that write operation happened after zone consistency check failure (in
> fill_super() after free_meta label). It caused unaligned writer error. To
> avoid
> it, I added __set_inuse() to keep inconsistent zones not selected for the
> write
> target.
>
> But that write operation happened because the write pointer fix curseg was
> done
> out of the SBI_POR_DOING protection. Now I learned SBI_POR_DOING can protect
> write operation, and I don't think set in use for the inconsistent zones is
> required. Will remove __set_inuse() calls from this patch and the first patch.
Also f2fs_stop_checkpoint() will stop any data/node/meta writeback, so it'd be
safe here.
Thanks,
>
> Thanks!
>
> --
> Best Regards,
> Shin'ichiro Kawasaki.
>
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