Messages in this thread | | | Subject | Re: [PATCH] scsi: do not requeue requests unaligned with device sector size | From | "Martin K. Petersen" <> | Date | Wed, 21 Dec 2016 09:01:11 -0500 |
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>>>>> "Mauricio" == Mauricio Faria de Oliveira <mauricfo@linux.vnet.ibm.com> writes:
Mauricio,
Mauricio> When a SCSI command (e.g., read operation) is partially Mauricio> completed with good status and residual bytes (i.e., not all Mauricio> the bytes from the specified transfer length were transferred) Mauricio> the SCSI midlayer will update the request/bios with the Mauricio> completed bytes and requeue the request in order to complete Mauricio> the remainder/pending bytes.
I agree with Christoph and Hannes. Some of this falls into the gray area that's outside of the T10 spec (HBA programming interface guarantees) but it seems like a deficiency in the HBA to report a byte count that's not a multiple of the logical block size. A block can't be partially written. Either it made it or it didn't. Regardless of how the I/O is being broken up into frames at the transport level and at which offset the transfer was interrupted.
I am also not a fan of the delayed retry stuff which seems somewhat orthogonal to the problem you're describing.
-- Martin K. Petersen Oracle Linux Engineering
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