Where should I mount my internal drive partitions?
As far as I searched on the internet, I came to know that
/Media = mount point for removable media that system do it itself ( usb drive , CD )
/Mnt = temporarily mounting anything manually
I can most probably mount anything wherever I want, but if that’s the case what’s the point of /mnt? Just to be organised I suppose.
TLDR
If /mnt is for temporary and /media is for removable where should permanent non-removable devices/partitions be mounted. i.e. an internal HDD which is formatted as NTFS but needs to be automounted at startup?
Asking with the sole reason to know that, what’s the practice of user who know Linux well, unlike me.
I know this is a silly question but I asked anyway.
I use
chown 000so that regular users fail to access a directory when no filesystem is mounted on it
My dummy brain can’t understand it man.
Isn’t someone can’t access a directory when no filesystem is mounted on it the default behaviour?
No, directories without anything mounted on them are normal directories - which checks out, since you can mount anything anywhere; unlike Windows volume letters, which only exist when volumes are mounted or detected by the OS.
When you mount a filesystem onto a directory, the OS “replaces” its contents AND permissions with that of the filesystem’s root.
Here’s an example with my setup (hopefully you’re somewhat familiar with Bash and the output of ls -l).
Imagine some random filesystem in /dev/sda1 owned by “user” which only contains a file named “/Hello World.txt”:
$ # List permissions of files in /mnt:
$ # note that none of the directories have read, write nor execute permissions
$ ls -la /mnt
drwxr-xr-x 1 root root 168 May 31 23:13 .
drwxr-xr-x 1 root root 128 May 31 23:14 ..
d--------- 1 root root 0 Aug 1 2020 a/
d--------- 1 root root 0 Feb 11 2022 b/
d--------- 1 root root 0 Aug 11 2021 vdisks/
$ # No read permission on a directory => directory entries cannot be listed
$ ls /mnt/a
cannot open directory '/mnt/a': Permission denied
$ sudo mount /dev/sda1 /mnt/a
$ # List again the permissions in /mnt: the root of /dev/sda1
$ # has rwxr-xr-x (or 755) permissions, which override the 000 of /mnt/a ...
$ ls -la /mnt
drwxr-xr-x 1 root root 168 May 31 23:13 .
drwxr-xr-x 1 root root 128 May 31 23:14 ..
drwxr-xr-x 1 root root 0 Aug 1 2020 a/
d--------- 1 root root 0 Feb 11 2022 b/
d--------- 1 root root 0 Aug 11 2021 vdisks/
$ # ... and its contents can be accessed by the mounted filesystem's owner:
$ ls -la /mnt/a
drwxr-xr-x 1 user user 168 May 31 23:13 .
drwxr-xr-x 1 root root 168 May 31 23:13 ..
-rw-r--r-- 1 user user 0 Jul 4 22:13 'Hello World.txt'
$ find /mnt
/mnt
/mnt/a
/mnt/a/Hello World.txt
find: ‘/mnt/b Permission denied
find: ‘/mnt/vdisks’: Permission denied
Please note that me setting permissions is just extreme pedantry, it’s not necessary at all and barely changes anything and if you’re still getting familiar with how the Linux VFS and its permissions work you can just ignore all of this.
OS “replaces” its contents AND permissions with that of the filesystem’s root.
So, the original content is lost forever?
setting permissions is just extreme pedantry
So, what’s the actual use case of it though? Even though it’s pedantry, it still there has to be some benefits, right?
I mean, What’s the need for you to deny the access of /mnt/a untill has mounted with something? One can just leave it as it is, right?
So, the original content is lost forever?
No, but it becomes invisible and inaccessible* as long as the filesystem is mounted over it - see this Stack Exchange question and accepted answer.
The benefits are marginal, for example I can see if a filesystem is mounted by simply typing ll /mnt (ll being an alias of ls -lA) - it comes handy with my system due to how I manage a bunch of virtual machines and their virtual disks, and it’s short and easy to type.
Some programs may refuse to write inside inaccessible directories, even if the root user can always modify regular files and directories as long as the filesystem supports it.
It’s not a matter of security, it’s more of a hint that if I’m trying to create something inside those directories then I’m doing something wrong (like forgetting to mount a filesystem) and “permission denied” errors let me know that I am.
