[SOLVED] SOLVED: BTRFS how to find the volume which is the parent of sub-volumes

marozsas · 05-11-2020, 12:52 PM

Hi there !

Code:

localhost:/home/miguel # btrfs subvolume list -t /var
ID      gen     top level       path
--      ---     ---------       ----
256     1993    5               @
257     1997    256             @/var
258     1964    256             @/usr/local
259     1997    256             @/tmp
260     1888    256             @/srv
261     1964    256             @/root
262     1905    256             @/opt
263     1888    256             @/boot/grub2/x86_64-efi
264     1888    256             @/boot/grub2/i386-pc
localhost:/home/miguel #

How do I know who is the parent dir (volume) of theses sub-volumes ?

I expect to see all theses sub-volumes as regular folders in the parent folder.

thank you in advance,

shruggy · 05-12-2020, 06:34 AM

Just guessing. Maybe

Code:

btrfs inspect-internal subvolid-resolve <ID> <MountPoint>

marozsas · 05-12-2020, 09:55 AM

Quote:

Originally Posted by shruggy

Just guessing. Maybe

Code:

btrfs inspect-internal subvolid-resolve <ID> <MountPoint>

no, not useful really....

Code:

root@fenix:/home/miguel# btrfs inspect-internal subvolid 272 /home/miguel/tmp
miguel/tmp
root@fenix:/home/miguel#

marozsas · 05-13-2020, 11:47 AM

Code:

root@fenix:/home/miguel# btrfs filesystem show | awk '/ +uuid:/ {print $4}' | xargs -L 1 -I{} blkid -t  UUID={}
/dev/sdc2: LABEL="home-btrf" UUID="af3bd7fe-5796-4248-9917-3e71a5a56ec6" UUID_SUB="f1d4dae9-d68d-4dbf-8b35-7a789ec3d7f2" TYPE="btrfs" PARTLABEL="home" PARTUUID="63b012c8-4c9f-49f5-85d9-da7e0f6b4a23"
root@fenix:/home/miguel#

Looks like btrfs does not have a tool to inform which is the parent folder or root folder of sub-volume.
You have to figure out based on the UUID returned by "btrfs filesystem show" and using blkid, return the device that match that UUID.

I hope this could be useful to someone.

cheers,

JZL240I-U · 05-14-2020, 12:37 PM

Thanks for coming back and sharing your solution

.