On 2012年12月15日 06:05, Eric Blake wrote:
On 12/14/2012 08:45 AM, Osier Yang wrote:
Just like for domain starting, this sets the disk's unpriv_sgio
if cdbfilter is specified when attaching disk.
---
src/qemu/qemu_driver.c | 23 +++++++++++++++++------
1 files changed, 17 insertions(+), 6 deletions(-)
+
+ /* Set sysfs unpriv_sgio if cdbfilter is specified. */
+ if (disk->cdbfilter) {
+ if (virSetDeviceUnprivSGIO(disk->src, NULL,
+ (disk->cdbfilter ==
+ VIR_DOMAIN_DISK_CDB_FILTER_NO)
+ ? 1 : 0)< 0) {
+ VIR_WARN("Failed to set unpriv_sgio of disk '%s'", disk->src);
+ goto end;
+ }
+ }
Again, does this do the right thing if some other domain already had
cdbfilter='no' (aka kernel allows SG_IO) but this domain omitted the
cdbfilter attribute (which defaults to cdbfilter='yes' but does not
satisfy the if(disk->cdbfilter) condition)?
I think it does the right thing, because not specifying "cdbfilter"
should mean it doesn't care about what the kernel setting is, not
means cdbfiler="yes" instead. Assuming that one used rawio="yes"
for a domain, and if we defaults cdbfilter to "yes", it will cause
regression, as the user still expects SG_IO commands can be executed
on the disk, however, it's disabled by cdbfilter="yes".
I suspect that will be
worked out when you rework things to use a tri-state rawio.
Of course, this is based on we use a separate XML tag like cdbfilter,
it won't stand anymore if we finally use a tri-state rawio.
Regards,
Osier
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