On Tue, May 31, 2011 at 5:00 AM, Stephane Chazelas <stephane_chaze...@yahoo.fr> wrote: > 2011-05-27 13:49:52 +0200, Andreas Philipp: > [...] >> > Thanks, I can understand that. What I don't get is how one creates >> > a subvol with a top-level other than 5. I might be missing the >> > obvious, though. >> > >> > If I do: >> > >> > btrfs sub create A btrfs sub create A/B btrfs sub snap A A/B/C >> > >> > A, A/B, A/B/C have their top-level being 5. How would I get a new >> > snapshot to be a child of A/B for instance? >> > >> > In my case, 285, was not appearing in the btrfs sub list output, >> > 287 was a child of 285 with path "data" while all I did was create >> > a snapshot of 284 (path u6:10022/vm+xfs@u8/xvda1/g8/v3/data in vol >> > 5) in u6:10022/vm+xfs@u8/xvda1/g8/v3/snapshots/2011-03-30 >> > >> > So I did manage to get a volume with a parent other than 5, but I >> > did not ask for it. > [...] >> Reconsidering the explanations on btrfs subvolume list in this thread >> I get the impression that a line in the output of btrfs subvolume list >> with top level other than 5 indicates that the backrefs from one >> subvolume to its parent are broken. >> >> What's your opinion on this? > [...] > > Given that I don't really get what the parent-child relationship > means in that context, I can't really comment. > > In effect, the snapshot had been created and was attached to the > right directory (but didn't appear in the sub list), and there > was an additional "data" volume that I had not asked for nor > created that had the snapshot above as parent and that did > appear in the sub list. > > It pretty much looks like a bug to me, I'd like to understand > more so that I can maybe try and avoid running into it again.
i'm actually really interested in the conclusion to this thread because i _want_ to create subvols with a new parent ... i didn't realize this wasn't possible (nor the mount option) until reading this thread. this would give me a little more flexibility with initcpio hooks and the like vs. packing the btrfs root with tons of hidden files [subvols] or using IDs directly ... i tried absolutely everything i could think of to reproduce this but all subvols ended up having a top level id of `5`. ... so, is there any known way to _purposefully_ create parented subvols with the current tools? -- C Anthony -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
