-x doesn't seem to respect filesystem boundary on BTRFS

[osamuaoki]

If you have a BTRFS snapshot directory on Linux system, "gdu -x" seems to peek into it while "du -x" doesn't peek into it.

Of course, such directory is not listed in /proc/self/mounts (/etc/mtab), since they are created by btrfs subvolume snapshot .... But stepping into such snapshot subvolume and alike are crossing filesystem boundary. The device number are different.

$ stat .
  File: .
  Size: 326       	Blocks: 0          IO Block: 4096   directory
Device: 0,77	Inode: 256         Links: 1
Access: (0755/drwxr-xr-x)  Uid: ( 1000/   osamu)   Gid: ( 1000/   osamu)
Access: 2023-01-29 00:24:37.239494047 +0900
Modify: 2022-12-20 15:37:26.049621026 +0900
Change: 2022-12-20 15:37:26.049621026 +0900
 Birth: 2021-11-07 17:30:03.545015150 +0900
Press any key to continue...

$ pwd
/home/osamu/github

I have snapshot:

$ stat .
  File: .
  Size: 326       	Blocks: 0          IO Block: 4096   directory
Device: 0,90	Inode: 256         Links: 1
Access: (0755/drwxr-xr-x)  Uid: ( 1000/   osamu)   Gid: ( 1000/   osamu)
Access: 2023-01-22 00:53:07.567855980 +0900
Modify: 2022-12-20 15:37:26.049621026 +0900
Change: 2022-12-20 15:37:26.049621026 +0900
 Birth: 2021-11-07 17:30:03.545015150 +0900
Press any key to continue...

$ pwd
/home/osamu/github/.bss.d/2023-01-21T23:43:23+00:00.hour

Then gdu seems to peek into this.

[lilydjwg]

A working patch (I had to gzip it because GitHub didn't accept my .patch file):

traditional-no-cross.patch.gz