On 6/28/22 16:56, Stefan Hajnoczi wrote:
> On Mon, Jun 27, 2022 at 08:19:14AM +0800, Sam Li wrote:
>> diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
>> index 2f0d8ac25a..3f2592b9f5 100644
>> --- a/qemu-io-cmds.c
>> +++ b/qemu-io-cmds.c
>> @@ -1706,6 +1706,122 @@ static const cmdinfo_t flush_cmd = {
>> .oneline = "flush all in-core file state to disk",
>> };
>>
>> +static int zone_report_f(BlockBackend *blk, int argc, char **argv)
>> +{
>> + int ret;
>> + int64_t offset, len, nr_zones;
>> + int i = 0;
>> +
>> + ++optind;
>> + offset = cvtnum(argv[optind]);
>> + ++optind;
>> + len = cvtnum(argv[optind]);
>> + ++optind;
>> + nr_zones = cvtnum(argv[optind]);
>> +
>> + g_autofree BlockZoneDescriptor *zones = g_new(BlockZoneDescriptor,
>> nr_zones);
>> + ret = blk_zone_report(blk, offset, len, &nr_zones, zones);
>> + while (i < nr_zones) {
>
> Does blk_zone_report() set nr_zones to 0 on failure or do we need to
> check if (ret < 0) here?
ret = 0 means "no zone reported" which happen only if nr_zones is 0 or the
start offset is past the end of the disk capacity. ret < 0 would mean that
a report zone operation was actually attempted and failed (EIO, ENOMEM etc).
>
>> + fprintf(stdout, "start: 0x%lx, len 0x%lx, cap 0x%lx, wptr 0x%lx, "
>
> The rest of the source file uses printf() instead of fprintf(stdout,
> ...). That's usually preferred because it's shorter.
>
>> + "zcond:%u, [type: %u]\n",
>
> Please use PRIx64 instead of lx format specifiers for portability. On
> 32-bit hosts lx is 32-bit, not 64-bit. You can grep QEMU's code for
> examples of PRIx64.
>
>> + zones[i].start, zones[i].length, zones[i].cap, zones[i].wp,
>> + zones[i].cond, zones[i].type);
>> + ++i;
>> + }
>
> A for loop is more idiomatic:
>
> for (int i = 0; i < nr_zones; i++) {
> ...
> }
>
>> + return ret;
>> +}
>> +
>> +static const cmdinfo_t zone_report_cmd = {
>> + .name = "zone_report",
>> + .altname = "f",
>> + .cfunc = zone_report_f,
>> + .argmin = 3,
>> + .argmax = 3,
>> + .args = "offset [offset..] len [len..] number [num..]",
>
> The arguments are "offset len number". This command does not accept
> optional offset/len/num arguments.
The arguments should be offset + len OR offset + number of zones. Having
the 3 of them does not make sense to me. The interface would then be:
(1) offset + len -> report all zones in the block range [offset .. offset
+ len - 1]
(2) offset + number of zones -> report at most "number of zones" from the
zone containing the block at "offset".
(2) matches the semantic used at the device command level. So I prefer to
approach (1).
>
>> + .oneline = "report a number of zones",
>
> Maybe "report zone information".
>
>> +};
>> +
>> +static int zone_open_f(BlockBackend *blk, int argc, char **argv)
>> +{
>> + int64_t offset, len;
>> + ++optind;
>> + offset = cvtnum(argv[optind]);
>> + ++optind;
>> + len = cvtnum(argv[optind]);
>> + return blk_zone_mgmt(blk, zone_open, offset, len);
>
> Where is the error reported? When I look at read_f() I see:
>
> if (ret < 0) {
> printf("read failed: %s\n", strerror(-ret));
>
> I think something similar is needed because qemu-io.c does not print an
> error message for us. The same is true for the other commands defined in
> this patch.
>
>> +}
>> +
>> +static const cmdinfo_t zone_open_cmd = {
>> + .name = "zone_open",
>> + .altname = "f",
>> + .cfunc = zone_open_f,
>> + .argmin = 2,
>> + .argmax = 2,
>> + .args = "offset [offset..] len [len..]",
>
> There are no optional offset/len args. The same is true for the other
> commands below.
--
Damien Le Moal
Western Digital Research
