Mhmm. Thanks. I'm begining to understand ;) Still : how can I see/know that id 5 is mapped to id 0 ? And why doing this? For what purpose? (is it a default btrfs behavior or is it set by the Ubuntu installer?)
2013/12/17 Chris Murphy <li...@colorremedies.com>: > > On Dec 16, 2013, at 4:54 PM, Nicolas Michel <be.nicolas.mic...@gmail.com> > wrote: > >> OK. thanks for your pretty fast answer :) >> >> Now my last question is: in this case it was "easy" as I know that I >> created all these subvolumes as parts of volume 0. But in the btrfs >> subv list / I don't see any information that tells me they belongs to >> id 0. If I have to debug a server/desktop and I don't know the >> hierarchy that has been made, how can I know that my tmp subvolume is >> indeed a child of id 0 ? > > When you do a subvol list it shows you what its top level is. Example: > > > > # btrfs subvol list / > ID 256 gen 1047 top level 5 path root > ID 258 gen 983 top level 5 path home > ID 259 gen 983 top level 5 path data > ID 276 gen 1012 top level 5 path root_ro > > > root is mounted at / > home is mounted at /hoome > data is mounted at /data > root_ro is not mounted at all > > > #cd /data > # btrfs subvol create data2 > Create subvolume './data2' > # btrfs subvol list / > ID 256 gen 1047 top level 5 path root > ID 258 gen 983 top level 5 path home > ID 259 gen 1048 top level 5 path data > ID 276 gen 1012 top level 5 path root_ro > ID 277 gen 1048 top level 5 path data/data2 > > # btrfs subvol list /data > ID 256 gen 1047 top level 5 path root > ID 258 gen 983 top level 5 path home > ID 259 gen 1048 top level 5 path data > ID 276 gen 1012 top level 5 path root_ro > ID 277 gen 1048 top level 259 path data2 > > > So notice that "top level 5 data/data2" means the same as "top level 259 > data2" because top level 259 implies data. > > You can also use btrfs subvol show <subvol> and it will give you more > information including whether it's a snapshot, what the parent is; and if > it's a parent that has snapshots it'll list the snapshots. > > # btrfs subvol show /data > /data > Name: data > uuid: bc45f4be-51c9-2848-bb68-d6e922b8e2bd > Parent uuid: - > Creation time: 2013-12-12 16:18:13 > Object ID: 259 > Generation (Gen): 1048 > Gen at creation: 11 > Parent: 5 > Top Level: 5 > Flags: - > Snapshot(s): > # btrfs subvol show /data/data2 > /data/data2 > Name: data2 > uuid: a66eddf9-107f-0448-a021-da417a982827 > Parent uuid: - > Creation time: 2013-12-16 17:11:36 > Object ID: 277 > Generation (Gen): 1048 > Gen at creation: 1048 > Parent: 259 > Top Level: 259 > Flags: - > Snapshot(s): > > > > Chris Murphy > -- Nicolas MICHEL -- 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
