Re: [RFC PATCH] getting misc stats/attributes via xattr API

From: Karel Zak
Date: Thu May 05 2022 - 08:30:57 EST


On Tue, May 03, 2022 at 02:23:23PM +0200, Miklos Szeredi wrote:
> Examples:
>
> $ getfattr -etext -n ":" .
> # file: .
> :="mnt:\000mntns:"
>
> $ getfattr -etext -n ":mnt:" .
> # file: .
> :mnt:="info"
>
> $ getfattr -etext -n ":mnt:info" .
> # file: .
> :mnt:info="21 1 254:0 / / rw,relatime - ext4 /dev/root rw\012"

Is there a way how to get mountinfo-like entry by mount ID for some
sub-tree? Something like:

getfattr -etext -n ":mnt:info:21" /

The interface has to be consistent with some notification system (I
see your question about fsnotify/fanotify at linux-fsdevel) and mount
ID seems better than paths due to over-mounts, etc.

> $ getfattr -etext -n ":mntns:" .
> # file: .
> :mntns:="21:\00022:\00024:\00025:\00023:\00026:\00027:\00028:\00029:\00030:\00031:"
>
> $ getfattr -etext -n ":mntns:28:" .
> # file: .
> :mntns:28:="info"

Karel

--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com