Re: find subvolume directories

[Andrei Borzenkov <arvidjaar@gmail.com>]

18.07.2019 15:00, Axel Burri пишет:
> On 13/07/2019 01.17, Ulli Horlacher wrote:
>> I need to find (all) subvolume directories.
>> I know, btrfs subvolumes root directories have inode #256, but a
>> "find / -inum 256" is horrible slow!
> 
> Having all required frameworks for this in btrbk, implementing a "list
> all subvolumes below <path>" command was quite easy to implement:
> 
> https://github.com/digint/btrbk/commit/e12d980502
> 
>  - get mounted filesystems from /proc/self/mountinfo
>  - fetch subvolumes using "btrfs subvolume list" (fast, needs root)
>  - filter and print subvolumes below mount point
> 
> Note that this approach needs root, as "btrfs subvolume list" requires
> "cap_sys_admin" and "cap_dac_read_search".
> 
> 
> Try it:
> 
> Download btrbk from "action-ls" feature branch (no dependencies needed):
> 
> # cd /tmp
> # wget https://raw.githubusercontent.com/digint/btrbk/action-ls/btrbk
> # chmod +x /tmp/btrbk
> 
> 
> List subvolumes below /home:
> 
> # ./btrbk ls /home
> # ./btrbk ls /home -t
> 
> 
> Comprehensive list of all accessible subvolumes:
> 
> # ./btrbk ls / --format=long
> 

Seems to work, also across non-btrfs mount point. One thing missing is
actual subvolume path (not current mount point).

> 
> Show commands run by btrbk:
> 
> # ./btrbk ls / -l debug
> 
> 
> If you need to run this as a regular user (and if you are brave), you
> can install setcap enabled btrfs binaries from:
> https://github.com/digint/btrfs-progs-btrbk
> 
> Hope this helps,
> 
> - Axel
>