[dm-devel] thin_repair doesn't do size checking on the output device

Zdenek Kabelac zkabelac at redhat.com
Mon May 19 07:37:12 UTC 2014

Dne 19.5.2014 09:13, M.H. Tsai napsal(a):
> Hi All,
> I'm using LVM2.2.02.106 and thin-provisioning-tools 0.3.2 on Ubuntu 13.10. I
> found that thin_repair doesn't do size checking on the output device, thus it
> will crash if the output device is larger than the space map's limitation
> (i.e., 255*16320*4096 bytes). The bitmap_count calculated by sm_disk::extend()
> might exceeded 255.
> The direct influence is that it cannot collaborate with the LVM2 "lvconvert
> --repair" command while the thinpool's metadata is exactly 16GiB. The reason
> is that the size of the pool metadata spare's DM target activated by
> _lvconvert_thinpool_repair() is 16384MiB, not 16192MiB. LVM2 only adjust the
> DM target's size to DM_THIN_MAX_METADATA_SIZE(16192MiB) while the metadata or
> the spare volume are activated within a thinpool.
> If this is a bug, I thought that it might be better to add size checking to
> thin_repair, since that users might use devices larger than 16GiB as the
> output device. Is that a feasible approach?

Yep - it's a bug and will need some fix.

Thanks for noticing this case.


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