Re: Is there some doc or some example of libbtrfs ?

[Pierre Couderc <pierre@couderc.eu>]

On 8/7/20 12:17 PM, Nikolay Borisov wrote:
>
> On 7.08.20 г. 12:36 ч., Pierre Couderc wrote:
>> Ho do I get programmatically btrfs xxxxx....?
>>
> Well, the example is in the source code of btrfs-progs, namely :
>
> btrfs_list_subvols_print
>   list_subvol_search
>
> TLDR You'd have to use the TREE_SEARCH ioctl which allows you to get
> data from btrfs' various trees. In order to figure out what data to pass
> to  the ioctl you'd have to familiarize yourself with the internal
> structure of btrfs trees to know which items represent a snapshot and
> which proper subvolumes. You should check the "ROOT ITEM" description at
> https://github.com/btrfs/btrfs-dev-docs/blob/master/tree-items.txt to
> see when a root item is a snapshot and not a subvolume.
>
A small tip for the next one :

To understand how and where some function is called (here 
btrfs_list_subvols_print), grep in in "cmds" subdirectory (here 
logically subvolume.c).