On 02/14/14 13:21, Hannes Reinecke wrote:
> On 02/14/2014 01:09 PM, Bart Van Assche wrote:
>> On 01/31/14 10:29, Hannes Reinecke wrote:
>>> + if (!target_id_size) {
>>> + /* Check for EMC Clariion extended inquiry */
>>> + if (!strncmp(sdev->vendor, "DGC ", 8) &&
>>> + sdev->inquiry_len > 160) {
>>> + target_id_size = sdev->inquiry[160];
>>> + target_id = sdev->inquiry + 161;
>>> + strcpy(target_id_str, "emc.");
>>> + memcpy(target_id_str + 4, target_id, target_id_size);
>>> + }
>>> + /* Check for HP EVA extended inquiry */
>>> + if (!strncmp(sdev->vendor, "HP ", 8) &&
>>> + !strncmp(sdev->model, "HSV", 3) &&
>>> + sdev->inquiry_len > 170) {
>>> + target_id_size = 16;
>>> + target_id = sdev->inquiry + 154;
>>> + strcpy(target_id_str, "naa.");
>>> + memcpy(target_id_str + 4, target_id, target_id_size);
>>> + }
>>> + }
>>
>> Being able to identify a storage array unambiguously is essential for
>> the new ALUA device handler algorithm introduced by this patch series.
>> What if a new storage array is introduced that is not covered by one of
>> the heuristics in this patch ? Has it been considered to let storage
>> array identification occur in user space instead of in the kernel ?
>
> As noted in the other mail, if we cannot decipher the array
> identifier the whole thing degrades into one pg per sdev.
> IE we cannot bunch RTPG / STPG for those.
> The idea here is that those arrays do not have any limitations,
> so that no special treatment is required.
>
> Adding identifiers from userspace are a bit tricky; there is no
> actual sysfs structure for the device handler.
> Which we would need if we were to use these tricks.
The reason I started asking about the target device ID is because for
Fusion-io ION devices we also encode the device ID in the INQUIRY
response (bytes 36..55; left aligned; padded with '\0'). The vendor name
is "FUSIONIO" and the first three characters of the product name are
"ION". Can you add the necessary support in the device identification
code ? Seems like it's time we get you a pair of those devices for
testing :-) An example:
# sg_inq -rl256 /dev/sdb | dd bs=1 count=20 skip=36 2>/dev/null | od -c
0000000 U S E 2 4 0 F W 6 5 \0 \0 \0 \0 \0 \0
0000020 \0 \0 \0 \0
0000024
Thanks,
Bart.
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