https://bugzilla.kernel.org/show_bug.cgi?id=191381 Bug ID: 191381 Summary: LIO ignores XCOPY source and destination descriptor IDs Product: IO/Storage Version: 2.5 Kernel Version: 4.9.0 Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: SCSI Assignee: linux-scsi@xxxxxxxxxxxxxxx Reporter: ddiss.dev@xxxxxxxxx Regression: No The EXTENDED COPY SCSI command (XCOPY) is used extensively by VMware ESX initiators, to offload to the iSCSI target, the process of copying data between a source and destination LU region. XCOPY is also supported by other initiators, such as ddpt (http://sg.danny.cz/sg/ddpt.html), libiscsi, etc. The XCOPY specification in SPC-4 (revision 37) states that the XCOPY source and destination device(s) should be derived from the copy source and copy destination descriptor (CSCD) IDs in the XCOPY segment descriptor. The CSCD IDs are generally (for block -> block copies), indexes into the corresponding CSCD list, i.e. ================================= XCOPY Header ================================= CSCD List - entry 0 + LU ID - entry 2 + LU ID ================================= Segment Descriptor List - segment 0 + src CSCD ID = (CSCD entry 0) + dest CSCD ID = (CSCD entry 1) + len + src lba + dest lba ================================= Currently LIO completely ignores the src and dest CSCD IDs in the Segment Descriptor List, and instead assumes that the first entry in the CSCD list corresponds to the source, and the second to the destination. This assumption appears to stand true for XCOPY requests from ESXi initiators. However, deviation from the spec may break other initiators - it causes a number of libiscsi tests to fail. -- You are receiving this mail because: You are the assignee for the bug. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
