On 2019/12/2 17:40, 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, reset the write pointer
> to place at the zone start.
>
> 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.
>
> Signed-off-by: Shin'ichiro Kawasaki <[email protected]>
> ---
> fs/f2fs/f2fs.h | 1 +
> fs/f2fs/segment.c | 126 ++++++++++++++++++++++++++++++++++++++++++++++
> fs/f2fs/super.c | 11 ++++
> 3 files changed, 138 insertions(+)
>
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 002c417b0a53..23a84d7f17b8 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -3156,6 +3156,7 @@ 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);
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 9b6c7ab67b93..48903b7a9d25 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -4370,6 +4370,90 @@ 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, ret;
> + struct seg_entry *se;
> +
> + if (zone->type != BLK_ZONE_TYPE_SEQWRITE_REQ)
> + return 0;
> +
> + 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, reset the write pointer.
> + */
> + if (last_valid_block + 1 == zone_block && zone->wp != zone->start) {
> + f2fs_notice(sbi,
> + "Zone without valid block has non-zero write "
> + "pointer. Reset the write pointer: wp[0x%x,0x%x]",
> + wp_segno, wp_blkoff);
> + ret = blkdev_zone_mgmt(fdev->bdev, REQ_OP_ZONE_RESET,
> + zone->start, zone->len, GFP_NOFS);
Should use __f2fs_issue_discard_zone() to cover multi-device support?
> + if (ret) {
> + f2fs_notice(sbi, "Reset zone failed: %s (errno=%d)",
> + fdev->path, ret);
> + return ret;
> + }
Just out of curiosity, how long will RESET command take normally?
Thanks,
> + }
> +
> + return 0;
> +}
> +
> static struct f2fs_dev_info *get_target_zoned_dev(struct f2fs_sb_info *sbi,
> block_t zone_blkaddr)
> {
> @@ -4442,6 +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));
> @@ -4492,11 +4580,49 @@ int f2fs_fix_curseg_write_pointer(struct f2fs_sb_info
> *sbi)
>
> return 0;
> }
> +
> +struct check_zone_write_pointer_args {
> + struct f2fs_sb_info *sbi;
> + struct f2fs_dev_info *fdev;
> +};
> +
> +static int check_zone_write_pointer_cb(struct blk_zone *zone, unsigned int
> idx,
> + void *data) {
> + struct check_zone_write_pointer_args *args;
> + args = (struct check_zone_write_pointer_args *)data;
> +
> + return check_zone_write_pointer(args->sbi, args->fdev, zone);
> +}
> +
> +int f2fs_check_write_pointer(struct f2fs_sb_info *sbi)
> +{
> + int i, ret;
> + struct check_zone_write_pointer_args args;
> +
> + for (i = 0; i < sbi->s_ndevs; i++) {
> + if (!bdev_is_zoned(FDEV(i).bdev))
> + continue;
> +
> + args.sbi = sbi;
> + args.fdev = &FDEV(i);
> + ret = blkdev_report_zones(FDEV(i).bdev, 0, BLK_ALL_ZONES,
> + check_zone_write_pointer_cb, &args);
> + if (ret < 0)
> + 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 5111e1ffe58a..755ad57c795b 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -3544,6 +3544,17 @@ 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);
>
_______________________________________________
Linux-f2fs-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
