On Tue, 2013-03-26 at 12:31 +0800, Lingzhu Xiang wrote: > On 03/26/2013 11:56 AM, Matthew Garrett wrote: > > Ok, so having thought some more about the actual problem (ie, Samsungs > > go wrong if there's too much used space marked as being active, not > > merely too much used space) I think we really want to be looking for the > > amount of active space rather than the remaining space value that > > QueryVariableInfo() gives us. Something like this (absolutely untested, > > provided here for comment) patch? I'll try rigging something up under > > OVMF to test it. This version certainly seems a little over-naive, since > > it won't handle the case of a variable that's being overwritten with > > something of a different size. > > > > commit 263c2ee36c67dfa6d869304a3b5aef7a14f1ec4e > > Author: Matthew Garrett <matthew.garrett@xxxxxxxxxx> > > Date: Mon Mar 25 13:40:28 2013 -0400 > > > > efi: Distinguish between "remaining space" and actually used space > > > > EFI implementations distinguish between space that is actively used by a > > variable and space that merely hasn't been garbage collected yet. Space > > that hasn't yet been garbage collected isn't available for use and so isn't > > counted in the remaining_space field returned by QueryVariableInfo(). > > > > Combined with commit 68d9298 this can cause problems. Some implementations > > don't garbage collect until the remaining space is smaller than the maximum > > variable size, and as a result check_var_size() will always fail once more > > than 50% of the variable store has been used even if most of that space is > > marked as available for garbage collection. The user is unable to create > > new variables, and deleting variables doesn't increase the remaining space. > > Do you mean they don't garbage collect across reboots? [...] Yes, see <http://article.gmane.org/gmane.linux.kernel.stable/47156>. Ben. -- Ben Hutchings I'm not a reverse psychological virus. Please don't copy me into your sig.
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