On Mon, Mar 19, 2018 at 02:02:23PM +0100, David Sterba wrote: > On Mon, Mar 19, 2018 at 08:20:10AM +0000, Hugo Mills wrote: > > On Mon, Mar 19, 2018 at 05:16:42PM +0900, Misono, Tomohiro wrote: > > > Currently, the top-level subvolume lacks the UUID. As a result, both > > > non-snapshot subvolume and snapshot of top-level subvolume do not have > > > Parent UUID and cannot be distinguisued. Therefore "fi show" of > > > top-level lists all the subvolumes which lacks the UUID in > > > "Snapshot(s)" filed. Also, it lacks the otime information. > > > > > > Fix this by adding the UUID and otime at the mkfs time. As a > > > consequence, snapshots of top-level subvolume now have a Parent UUID and > > > UUID tree will create an entry for top-level subvolume at mount time. > > > This should not cause the problem for current kernel, but user program > > > which relies on the empty Parent UUID may be affected by this change. > > > > Is there any way of adding a UUID to the top level subvol on an > > existing filesystem? It would be helpful not to have to rebuild every > > filesystem in the world to fix this. > > We can do that by a special purpose tool. The easiest way is to set the > uuid on an unmouted filesystem, but as this is a one-time action I hope > this is acceptable. Added to todo, thanks for the suggestion.
Sounds good to me. Hugo. -- Hugo Mills | Talking about music is like dancing about hugo@... carfax.org.uk | architecture http://carfax.org.uk/ | PGP: E2AB1DE4 | Frank Zappa
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