Re: [libvirt] [PATCH/RFC]: don't ignore errors to save the domain status file
On Sat, Jan 31, 2009 at 02:32:09PM +0100, Guido G?nther wrote:
Hi,
we currently don't report errors to save qemu's domain status file back
to the caller. That was o.k. as long as the code was there for testing
but now that the XML is being picked up on daemon restart we must
handle these.
The attached patch does that, although I'm not confident that it's
enough. While we return error on device attach/unattach the device
actually got attached/unattached already. Same is true for
suspend/resume.
A better solution would be to write out the new domain status into a
temp file and simply call rename(2) on it when the attach/unattach
succeeds and discard it if it fails. This would minimize the possible
error conditions like disk full, missing permissions to write into that
directory etc. Does this sound reasonable?
Yeah, I think that sounds like a reasonable idea
virPrepareStatusFile()
virSaveStatusFile()
the former creates the temporary file, and the latter does
the rename().
In the prepare stage, we could also do a access(R_OK)
check on the eventual target, as a sanity check that
we're likely to be able to complete the rename() later.
Daniel
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