On 05/04/2016 17:16, Alex Bligh wrote: > > > * Document that sending FUA for commands that do nothing is permissible, > > > but > > > 'SHOULD NOT' be done; an existing client does this. > > > > Can you send a pointer to the discussion? FUA on reads definitely does > > *something* in SCSI (it ensures that the data is moved out of the > > volatile cache prior to the read, similar to what QEMU implements). > > Sure. I got a solitary one reply that referenced the kernel, which > was copied to this list - see below.
Ok, thanks. > I don't have strong feelings either way, but the safer option would > be to not REQUIRE the server to rely on any FUA read behaviour (I'm > already saying they should ignore the bit on reads). Qemu can't > currently RELY on FUA on reads, as it's not documented anywhere > and with the reference NBD server did nothing until recently; recently > it started errorring the read! See below. Right. However, bugs get fixed... Paolo > On that basis I chose to go with 'FUA on read does nothing'. > > If the kernel actually does something on read perhaps we should > reconsider. ------------------------------------------------------------------------------ _______________________________________________ Nbd-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/nbd-general
