Re: [PATCH 1/1] f2fs: Fix zoned block device support

[Jaegeuk Kim <jaegeuk@kernel.org>]

Hello,

On 02/27, Masato Suzuki wrote:
> The introduction of the multi-device feature partially broke the support
> for zoned block devices. In the function f2fs_scan_devices, sbi->devs
> allocation and initialization is skipped in the case of a single device
> mount. This result in no device information structure being allocated
> for the device. This is fine if the device is a regular device, but in
> the case of a zoned block device, the device zone type array is not
> initialized, which causes the function __f2fs_issue_discard_zone to fail
> as get_blkz_type is unable to determine the zone type of a section.
> 
> Fix this by always allocating and initializing the sbi->devs device
> information array even in the case of a single device if that device is
> zoned. For this particular case, make sure to obtain a reference on the
> single device so that the call to blkdev_put() in destroy_device_list
> operates as expected.
> 
> Signed-off-by: Masato Suzuki <masato.suzuki@wdc.com>

Thank you for the patch.
I've added:

Fixes: 3c62be17d4f562f4 ("f2fs: support multiple devices")
Cc: <stable@vger.kernel.org> # v4.10

Thanks,

> Acked-by: Damien Le Moal <damien.lemoal@wdc.com>
> ---
>  fs/f2fs/super.c | 67 +++++++++++++++++++++++++++++++++++++--------------------
>  1 file changed, 44 insertions(+), 23 deletions(-)
> 
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 46fd30d..287fcbd 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1698,36 +1698,55 @@ int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover)
>  static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
>  {
>  	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
> +	unsigned int max_devices = MAX_DEVICES;
>  	int i;
>  
> -	for (i = 0; i < MAX_DEVICES; i++) {
> -		if (!RDEV(i).path[0])
> +	/* Initialize single device information */
> +	if (!RDEV(0).path[0]) {
> +		if (!bdev_is_zoned(sbi->sb->s_bdev))
>  			return 0;
> +		max_devices = 1;
> +	}
>  
> -		if (i == 0) {
> -			sbi->devs = kzalloc(sizeof(struct f2fs_dev_info) *
> -						MAX_DEVICES, GFP_KERNEL);
> -			if (!sbi->devs)
> -				return -ENOMEM;
> -		}
> +	/*
> +	 * Initialize multiple devices information, or single
> +	 * zoned block device information.
> +	 */
> +	sbi->devs = kcalloc(max_devices, sizeof(struct f2fs_dev_info),
> +				GFP_KERNEL);
> +	if (!sbi->devs)
> +		return -ENOMEM;
>  
> -		memcpy(FDEV(i).path, RDEV(i).path, MAX_PATH_LEN);
> -		FDEV(i).total_segments = le32_to_cpu(RDEV(i).total_segments);
> -		if (i == 0) {
> -			FDEV(i).start_blk = 0;
> -			FDEV(i).end_blk = FDEV(i).start_blk +
> -				(FDEV(i).total_segments <<
> -				sbi->log_blocks_per_seg) - 1 +
> -				le32_to_cpu(raw_super->segment0_blkaddr);
> -		} else {
> -			FDEV(i).start_blk = FDEV(i - 1).end_blk + 1;
> -			FDEV(i).end_blk = FDEV(i).start_blk +
> -				(FDEV(i).total_segments <<
> -				sbi->log_blocks_per_seg) - 1;
> -		}
> +	for (i = 0; i < max_devices; i++) {
>  
> -		FDEV(i).bdev = blkdev_get_by_path(FDEV(i).path,
> +		if (i > 0 && !RDEV(i).path[0])
> +			break;
> +
> +		if (max_devices == 1) {
> +			/* Single zoned block device mount */
> +			FDEV(0).bdev =
> +				blkdev_get_by_dev(sbi->sb->s_bdev->bd_dev,
>  					sbi->sb->s_mode, sbi->sb->s_type);
> +		} else {
> +			/* Multi-device mount */
> +			memcpy(FDEV(i).path, RDEV(i).path, MAX_PATH_LEN);
> +			FDEV(i).total_segments =
> +				le32_to_cpu(RDEV(i).total_segments);
> +			if (i == 0) {
> +				FDEV(i).start_blk = 0;
> +				FDEV(i).end_blk = FDEV(i).start_blk +
> +				    (FDEV(i).total_segments <<
> +				    sbi->log_blocks_per_seg) - 1 +
> +				    le32_to_cpu(raw_super->segment0_blkaddr);
> +			} else {
> +				FDEV(i).start_blk = FDEV(i - 1).end_blk + 1;
> +				FDEV(i).end_blk = FDEV(i).start_blk +
> +					(FDEV(i).total_segments <<
> +					sbi->log_blocks_per_seg) - 1;
> +			}
> +			FDEV(i).bdev = blkdev_get_by_path(FDEV(i).path,
> +					sbi->sb->s_mode, sbi->sb->s_type);
> +		}
>  		if (IS_ERR(FDEV(i).bdev))
>  			return PTR_ERR(FDEV(i).bdev);
>  
> @@ -1747,6 +1766,8 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
>  					"Failed to initialize F2FS blkzone information");
>  				return -EINVAL;
>  			}
> +			if (max_devices == 1)
> +				break;
>  			f2fs_msg(sbi->sb, KERN_INFO,
>  				"Mount Device [%2d]: %20s, %8u, %8x - %8x (zone: %s)",
>  				i, FDEV(i).path,
> -- 
> 2.9.3
> 
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