Re: [PATCH v2 3/3] blkid: support zone reset for wipefs

[Damien Le Moal <Damien.LeMoal@wdc.com>]

On 2021/04/14 10:33, Naohiro Aota wrote:
> We cannot overwrite superblock magic in a sequential required zone. So,
> wipefs cannot work as it is. Instead, this commit implements the wiping by
> zone resetting.
> 
> Zone resetting must be done only for a sequential write zone. This is
> checked by is_conventional().
> 
> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
> ---
>  libblkid/src/probe.c | 79 ++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 73 insertions(+), 6 deletions(-)
> 
> diff --git a/libblkid/src/probe.c b/libblkid/src/probe.c
> index 9d180aab5242..23c3621627d4 100644
> --- a/libblkid/src/probe.c
> +++ b/libblkid/src/probe.c
> @@ -107,6 +107,7 @@
>  #include <stdint.h>
>  #include <stdarg.h>
>  #include <limits.h>
> +#include <stdbool.h>
>  
>  #include "blkidP.h"
>  #include "all-io.h"
> @@ -1228,6 +1229,48 @@ int blkid_do_probe(blkid_probe pr)
>  	return rc;
>  }
>  
> +#ifdef HAVE_LINUX_BLKZONED_H
> +static int is_conventional(blkid_probe pr, uint64_t offset)
> +{
> +	struct blk_zone_report *rep = NULL;
> +	size_t rep_size;
> +	int ret;
> +	uint64_t zone_mask;
> +
> +	if (!pr->zone_size)
> +		return 1;
> +
> +	rep_size = sizeof(struct blk_zone_report) + sizeof(struct blk_zone);
> +	rep = calloc(1, rep_size);
> +	if (!rep)
> +		return -1;
> +
> +	zone_mask = ~(pr->zone_size - 1);
> +	rep->sector = (offset & zone_mask) >> 9;
> +	rep->nr_zones = 1;
> +	ret = ioctl(blkid_probe_get_fd(pr), BLKREPORTZONE, rep);
> +	if (ret) {
> +		free(rep);
> +		return -1;
> +	}
> +
> +	if (rep->zones[0].type == BLK_ZONE_TYPE_CONVENTIONAL)
> +		ret = 1;
> +	else
> +		ret = 0;
> +
> +	free(rep);
> +
> +	return ret;
> +}
> +#else
> +static inline int is_conventional(blkid_probe pr __attribute__((__unused__)),
> +				  uint64_t offset __attribute__((__unused__)))
> +{
> +	return 1;
> +}
> +#endif
> +
>  /**
>   * blkid_do_wipe:
>   * @pr: prober
> @@ -1267,6 +1310,7 @@ int blkid_do_wipe(blkid_probe pr, int dryrun)
>  	const char *off = NULL;
>  	size_t len = 0;
>  	uint64_t offset, magoff;
> +	bool conventional;
>  	char buf[BUFSIZ];
>  	int fd, rc = 0;
>  	struct blkid_chain *chn;
> @@ -1302,6 +1346,11 @@ int blkid_do_wipe(blkid_probe pr, int dryrun)
>  	if (len > sizeof(buf))
>  		len = sizeof(buf);
>  
> +	rc = is_conventional(pr, offset);
> +	if (rc < 0)
> +		return rc;
> +	conventional = rc == 1;
> +
>  	DBG(LOWPROBE, ul_debug(
>  	    "do_wipe [offset=0x%"PRIx64" (%"PRIu64"), len=%zu, chain=%s, idx=%d, dryrun=%s]\n",
>  	    offset, offset, len, chn->driver->name, chn->idx, dryrun ? "yes" : "not"));
> @@ -1309,13 +1358,31 @@ int blkid_do_wipe(blkid_probe pr, int dryrun)
>  	if (lseek(fd, offset, SEEK_SET) == (off_t) -1)
>  		return -1;
>  
> -	memset(buf, 0, len);
> -
>  	if (!dryrun && len) {
> -		/* wipen on device */
> -		if (write_all(fd, buf, len))
> -			return -1;
> -		fsync(fd);
> +		if (conventional) {
> +			memset(buf, 0, len);
> +
> +			/* wipen on device */
> +			if (write_all(fd, buf, len))
> +				return -1;
> +			fsync(fd);
> +		} else {
> +#ifdef HAVE_LINUX_BLKZONED_H
> +			uint64_t zone_mask = ~(pr->zone_size - 1);
> +			struct blk_zone_range range = {
> +				.sector = (offset & zone_mask) >> 9,
> +				.nr_sectors = pr->zone_size >> 9,
> +			};
> +
> +			rc = ioctl(fd, BLKRESETZONE, &range);
> +			if (rc < 0)
> +				return -1;
> +#else
> +			/* Should not reach here */
> +			assert(0);
> +#endif
> +		}
> +
>  		pr->flags &= ~BLKID_FL_MODIF_BUFF;	/* be paranoid */
>  
>  		return blkid_probe_step_back(pr);
> 

Looks OK to me.

Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>

-- 
Damien Le Moal
Western Digital Research