On 01/13/2012 09:35 PM, Roland Dreier wrote: > In general, with my target vendor hat on, I'd be very interested in > what special SCSI commands the Linux initiator stack might want > to use. Extended copy is one (very complex) case -- and BTW > Microsoft seems to plan on using XCOPY LITE with NTFS. > > Another possibly interesting example would be COMPARE AND > WRITE for clustered filesystems. > > Any other storage operations that FS developers might want > from the block device? (Either standard SCSI commands or > more speculative stuff that T10 hasn't thought of yet) > copy-and-modify the command looks like a a write with destination [write_start, num_sectors] The command also receives a read destination [read_start, num_sectors] where read_start <= write_start && write_start+num_sectors <= read_start+num_sectors That's for the like of pNFS blocks layout where the FS maintains a copy-on-write with FS blocks larger than a sector. Today it needs to do the copy then the modification. (2 + 1) operations instead of 1 Na, too marginal. Is it worth it? It might depend on the FS block size. Just some crazy idea Boaz > - R. > -- > 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 -- 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
