Messages in this thread | | | Date | Wed, 02 May 2012 15:59:59 +0200 | From | Paolo Bonzini <> | Subject | Re: [PATCH] scsi: Silence unnecessary warnings about ioctl to partition |
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Il 02/05/2012 15:51, Jan Kara ha scritto: >> > NACK. I would bet that all the warnings you've seen are for ioctl that >> > would have failed anyway with ENOTTY. > Actually, you would loose the bet ;)
Doh. :)
> The customer was complaining about > warning about SG_IO ioctl. Apparently some Veritas filesystem thread generates > a *lot* of these (I don't know if they happen to do all the filesystem IO > with SG_IO and I'm not sure I want to know ;).
Can you at least ask the customer for help finding which command was sent? And perhaps have them try a kernel that blocks SG_IO to see what breaks if anything?
> Also I tend to side with Alan that I don't quite see > the point in trying to restrict CAP_SYS_RAWIO threads and thus breaking the > compatibility
For example, we have a customer that wants this:
* a VM should be able to send vendor-specific commands to a disk via SG_IO (vendor-specific commands require CAP_SYS_RAWIO).
* they want to assign logical volumes or partitions to the same VM without letting it read or write outside the logical volume or partition.
Of course a better solution for this would be customizable filters for SG_IO commands, where a privileged application would open the block device with CAP_SYS_RAWIO, set the filter and hand the file descriptor to QEMU. Or alternatively some extension of the device cgroup. But either solution would require a large amount of work.
Paolo
> (if ioctls would be restricted for partitions from the > beginning, then sure it seems like a cleaner choice). But I don't feel that > strongly about it.
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