On Dec 16, 2013, at 4:54 PM, Nicolas Michel <be.nicolas.michel@xxxxxxxxx> 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 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
