On Tue, Oct 11, 2022 at 10:50:06AM -0400, Sasha Levin wrote: > From: Qu Wenruo <wqu@xxxxxxxx> > > [ Upstream commit e562a8bdf652b010ce2525bcf15d145c9d3932bf ] > > Introduce a new runtime flag, BTRFS_QGROUP_RUNTIME_FLAG_CANCEL_RESCAN, > which will inform qgroup rescan to cancel its work asynchronously. > > This is to address the window when an operation makes qgroup numbers > inconsistent (like qgroup inheriting) while a qgroup rescan is running. > > In that case, qgroup inconsistent flag will be cleared when qgroup > rescan finishes. > But we changed the ownership of some extents, which means the rescan is > already meaningless, and the qgroup inconsistent flag should not be > cleared. > > With the new flag, each time we set INCONSISTENT flag, we also set this > new flag to inform any running qgroup rescan to exit immediately, and > leaving the INCONSISTENT flag there. > > The new runtime flag can only be cleared when a new rescan is started. Qu, does this patch make sense for stable on itself? It was part of a series adding some new flags and the sysfs knob. As I read it there's a case where it can affect how the rescan is done and that it can be cancelled but still am not sure if it's worth the backport.
