Hi Hannes and Jens,
> On Feb 3, 2022, at 5:47 AM, Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> On 2/3/22 12:24 AM, Hannes Reinecke wrote:
>> On 2/3/22 07:52, Song Liu wrote:
>>> CC linux-block (it was a typo in the original email)
>>>
>>> On Wed, Feb 2, 2022 at 10:40 PM Song Liu <song@xxxxxxxxxx> wrote:
>>>>
>>>> Currently, drivers reports BLK_STS_IOERR for devices that are not full
>>>> online or being removed. This behavior could cause confusion for users,
>>>> as they are not really I/O errors from the device.
>>>>
>>>> Solve this issue with a new state BLK_STS_OFFLINE, which reports "device
>>>> offline error" in dmesg instead of "I/O error".
>>>>
>>>> Signed-off-by: Song Liu <song@xxxxxxxxxx>
>>>> ---
>>>> block/blk-core.c | 1 +
>>>> include/linux/blk_types.h | 7 +++++++
>>>> 2 files changed, 8 insertions(+)
>>>>
>>>> diff --git a/block/blk-core.c b/block/blk-core.c
>>>> index 61f6a0dc4511..24035dd2eef1 100644
>>>> --- a/block/blk-core.c
>>>> +++ b/block/blk-core.c
>>>> @@ -164,6 +164,7 @@ static const struct {
>>>> [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" },
>>>> [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" },
>>>> [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" },
>>>> + [BLK_STS_OFFLINE] = { -EIO, "device offline" },
>>>>
>>>> /* device mapper special case, should not leak out: */
>>>> [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" },
>>>> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
>>>> index fe065c394fff..5561e58d158a 100644
>>>> --- a/include/linux/blk_types.h
>>>> +++ b/include/linux/blk_types.h
>>>> @@ -153,6 +153,13 @@ typedef u8 __bitwise blk_status_t;
>>>> */
>>>> #define BLK_STS_ZONE_ACTIVE_RESOURCE ((__force blk_status_t)16)
>>>>
>>>> +/*
>>>> + * BLK_STS_OFFLINE is returned from the driver when the target device is offline
>>>> + * or is being taken offline. This could help differentiate the case where a
>>>> + * device is intentionally being shut down from a real I/O error.
>>>> + */
>>>> +#define BLK_STS_OFFLINE ((__force blk_status_t)17)
>>>> +
>>>> /**
>>>> * blk_path_error - returns true if error may be path related
>>>> * @error: status the request was completed with
>>>> --
>>>> 2.30.2
>>>>
>> Please do not overload EIO here.
>> EIO already is a catch-all error if we don't know any better, but for
>> the 'device offline' case we do (or rather should).
>> Please map it onto 'ENODEV' or 'ENXIO'.
>
> It's deliberately EIO as not to force a change in behavior. I don't mind
> using something else, but that should be a separate change then.
Thanks for these feedbacks. Shall I send v2 with an extra patch that
changes EIO to ENODEV/ENXIO? Or shall we do that in a follow up patch?
Also, any preference between ENODEV and ENXIO?
Thanks,
Song
