btrfs-progs: eliminate bogus IOC_DEV_INFO call
diff mbox

Message ID 20170727192446.27158-1-hans.van.kranenburg@mendix.com
State New
Headers show

Commit Message

Hans van Kranenburg July 27, 2017, 7:24 p.m. UTC
Device ID numbers always start at 1, not at 0. The first IOC_DEV_INFO
call does not make sense, since it will always return ENODEV.

ioctl(3, BTRFS_IOC_DEV_INFO, {devid=0}) = -1 ENODEV (No such device)

Signed-off-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
---
 cmds-fi-usage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Henk Slager July 28, 2017, 9:49 a.m. UTC | #1
On Thu, Jul 27, 2017 at 9:24 PM, Hans van Kranenburg
<hans.van.kranenburg@mendix.com> wrote:
> Device ID numbers always start at 1, not at 0. The first IOC_DEV_INFO
> call does not make sense, since it will always return ENODEV.

When there is a btrfs-replace ongoing, there is a Device ID 0

> ioctl(3, BTRFS_IOC_DEV_INFO, {devid=0}) = -1 ENODEV (No such device)
>
> Signed-off-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
> ---
>  cmds-fi-usage.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/cmds-fi-usage.c b/cmds-fi-usage.c
> index 101a0c4..52c4c62 100644
> --- a/cmds-fi-usage.c
> +++ b/cmds-fi-usage.c
> @@ -535,7 +535,7 @@ static int load_device_info(int fd, struct device_info **device_info_ptr,
>                 return 1;
>         }
>
> -       for (i = 0, ndevs = 0 ; i <= fi_args.max_id ; i++) {
> +       for (i = 1, ndevs = 0 ; i <= fi_args.max_id ; i++) {
>                 if (ndevs >= fi_args.num_devices) {
>                         error("unexpected number of devices: %d >= %llu", ndevs,
>                                 (unsigned long long)fi_args.num_devices);
> --
> 2.11.0
>
> --
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Hans van Kranenburg July 29, 2017, 8:20 p.m. UTC | #2
On 28/07/2017 11:49, Henk Slager wrote:
> On Thu, Jul 27, 2017 at 9:24 PM, Hans van Kranenburg
> <hans.van.kranenburg@mendix.com> wrote:
>> Device ID numbers always start at 1, not at 0. The first IOC_DEV_INFO
>> call does not make sense, since it will always return ENODEV.
>
> When there is a btrfs-replace ongoing, there is a Device ID 0

Aha... thanks for teaching me something new today. :) Actually, I 
remember having seen it a time earlier yes.

So, this one goes to /dev/null!

Hans

>
>> ioctl(3, BTRFS_IOC_DEV_INFO, {devid=0}) = -1 ENODEV (No such device)
>>
>> Signed-off-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com>
>> ---
>>   cmds-fi-usage.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/cmds-fi-usage.c b/cmds-fi-usage.c
>> index 101a0c4..52c4c62 100644
>> --- a/cmds-fi-usage.c
>> +++ b/cmds-fi-usage.c
>> @@ -535,7 +535,7 @@ static int load_device_info(int fd, struct device_info **device_info_ptr,
>>                  return 1;
>>          }
>>
>> -       for (i = 0, ndevs = 0 ; i <= fi_args.max_id ; i++) {
>> +       for (i = 1, ndevs = 0 ; i <= fi_args.max_id ; i++) {
>>                  if (ndevs >= fi_args.num_devices) {
>>                          error("unexpected number of devices: %d >= %llu", ndevs,
>>                                  (unsigned long long)fi_args.num_devices);
>> --
>> 2.11.0
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html

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Patch
diff mbox

diff --git a/cmds-fi-usage.c b/cmds-fi-usage.c
index 101a0c4..52c4c62 100644
--- a/cmds-fi-usage.c
+++ b/cmds-fi-usage.c
@@ -535,7 +535,7 @@  static int load_device_info(int fd, struct device_info **device_info_ptr,
 		return 1;
 	}
 
-	for (i = 0, ndevs = 0 ; i <= fi_args.max_id ; i++) {
+	for (i = 1, ndevs = 0 ; i <= fi_args.max_id ; i++) {
 		if (ndevs >= fi_args.num_devices) {
 			error("unexpected number of devices: %d >= %llu", ndevs,
 				(unsigned long long)fi_args.num_devices);