>>>>> "Yiwen" == jiangyiwen <jiangyiwen@xxxxxxxxxx> writes: Yiwen, Yiwen> First, I don't understand why blk_peek_request() return Yiwen> EREMOTEIO, as I know, in this situation we only prepare scsi Yiwen> command without sending to device, and I think EREMOTEIO should Yiwen> be returned only when IO has already sent to device, maybe I Yiwen> don't understand definition of EREMOTEIO. So, Why don't return Yiwen> the errno with EOPNOTSUPP? DM currently has special handling for EREMOTEIO failures (because that's what we'd return when a device responds with ILLEGAL REQUEST). I am not opposed to returning EOPNOTSUPP but it would require more changes and since this is a bugfix for stable I want to keep it as small as possible. Yiwen> In addition, I still worried with whether there has other Yiwen> situations which will return EIO or other error. In this way, Yiwen> MD/DM still can happen this type of problem, so I think may be in Yiwen> multipath we still needs a protection to avoid it. There are various error scenarios where we can end up bailing with a BLKPREP_KILL. But the general rule of thumb is that these conditions all demand a retry. The optional commands like WRITE SAME and UNMAP are special in that they are irrecoverable. Yiwen> At last, I have a additional problem, I remember that you Yiwen> previously send a series of patches about XCOPY, why don't have Yiwen> any news latter later? I very much expect that I can see these Yiwen> patches which are merged into kernel. I am working on a refresh of the series that includes token-based copy offload support in addition to EXTENDED COPY. The patches depend on Mike Christie's request flag patch series which has yet to be merged. -- Martin K. Petersen Oracle Linux Engineering -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
