On Tue, Jan 12, 2016 at 4:23 PM, Andrew Price <anpr...@redhat.com> wrote: > On 12/01/16 13:30, Andreas Gruenbacher wrote: >> >> Is it guaranteed that the kernel will never set the new rg_skip field >> if it hasn't verified that the next resource group is where it thinks >> it is? > > > No, but rg_skip is set from the ri_addr of the next resource group in the > rindex and gfs2 generally trusts the rindex so if it's corrupt then there'll > be other problems down the line. > >> Otherwise we could end up with incorrect fsck "hints" for >> corrupted filesystems, which would make things worse. > > > I don't think it would make things worse. fsck.gfs2 will be able to check > whether the rg_skip field is correct by checking it against the rindex and > whether there's an rgrp where it's pointing (and checking that it's within a > sensible range). Before, we only had the rindex and the rgrp header to check > against each other but now we have a third factor. > > That said, the fsck.gfs2 case is only one of the ways this would be useful. > The original plan was to generally reduce dependence on the rindex, > effectively allowing us to iterate over all rgrps without reading it in. > Though I don't recall the specific issue which motivated it, I can think of > cases where it would improve things.
It would be helpful to explain the reasons for adding rg_skip in the patch description. Thanks, Andreas
