birthtime support on Linux

[ThomasWaldmann]

I just noticed that for 1.4-maint, a mounted archive does not show birthtime in stat output.

The original file had a birthtime.

So:

• is birthtime not archived?
• is FUSE getattr not processing birthtime, even if it is there?

Debian Trixie, borg with pyfuse3.

[ThomasWaldmann]

There seems to be a Python os.stat limitation on Linux (demonstrated on Ubuntu 24.04):

Python 3.12.3 (main, Nov  6 2025, 13:44:16) [GCC 13.3.0] on linux
>>> os.stat(".")
os.stat_result(st_mode=16872, st_ino=1868593, st_dev=2050, st_nlink=18,
               st_uid=1000, st_gid=1000, st_size=4096,
               st_atime=1767190190, st_mtime=1767189974, st_ctime=1767189974)

On the shell:

tw@ubuntu:~$ stat .
  File: .
  Size: 4096      	Blocks: 8          IO Block: 4096   directory
Device: 8,2	Inode: 1868593     Links: 18
Access: (0750/drwxr-x---)  Uid: ( 1000/      tw)   Gid: ( 1000/      tw)
Access: 2025-12-31 15:09:50.949888448 +0100
Modify: 2026-01-04 14:23:34.787923283 +0100
Change: 2026-01-04 14:23:34.787923283 +0100
 Birth: 2023-07-25 18:58:38.408000000 +0200

[ThomasWaldmann]

There also is a pyfuse3 limitation:

On Linux, the GET_BIRTHTIME macro just returns 0.