Allow users other than the owner to change the mtime of a file

groszdani · 09-05-2009, 09:06 AM

If I mount a FAT filesystem (e. g. a pendrive) as root with umask=000, the owner of every file on it will be root but any user will be able to write on it. If a non-root user writes to it, file modification times are not preserved because only the owner of the files can change the mtimes.

Is there a way to allow any user who can change the contents of a file to change its mtime as well? To me it would seem logical.

blackhole54 · 09-08-2009, 06:00 PM

I just tried this on Ubuntu 6.10 using kernel 2.6.17-12-generic and the modification time was adjusted for a normal user as I would expect. Perhaps this is a bug in the software you have?

For the record, as root:

Code:

mount -o umask=000 /dev/sdb1 /mnt/usb
echo hi > /mnt/usb/work_directory/test_mod

As a normal user:

Code:

echo there >> /mnt/usb/work_directory/test_mod

And the modification time reflected the change. I then edited the file as the normal user using vi, and again mtime changed.