Raspberry Pi 3 (Raspbian) programatically accessing a USB drive: best way to do this?

I'm running Raspbian 1.0, v9/15 on an RP3. I'm working on an application that will access a dedicated USB flash drive to store collected data. The static path to write the data is "/media/user/kingston". This works great unless I have a system crash at which point the owner and group for "/media/user/kingston" are changed to root, and the mount point for the flash drive now is now changed to "/media/user/kingston1" which (clearly) does not work with the static path defined in my application. Is there a standard dynamic path option that is available for this device and OS? Thanks in advance...

Update: Based on BJ Black's advice, this is what I added to fstab after creating a directory named /usb at the root of the filesystem,

/dev/sda1  /usb  vfat noatime,nofail,user,rw,exec,umask=000   0  3

The advantages are, 1) allows bootup even when no USB drive is inserted, 2) allows any usb storage device to be used here.

Disadvantage is that the system must be powered down (or drive umounted) before flash drive is removed otherwise bad things happen, (I tried this). Question: Is there anything that I can do to reduce the "bad things" in the event that someone pulls out the usb while it is still mounted? Thanks in advance.

Solution

In general, I tend to prefer using a hard mount point for this kind of thing. There are possibly some neat tricks in /sys (or by using a grep against the output of mount(1) or /proc/mounts), but they'll fail as soon as you change out your Kingston stick for some other vendor (yuck).

Have a look at this link to better understand what's automounting your usb stick and how to shut that mechanism off.

As for mounting in a permanent place, I'd try either:

Create a mount point (say /data) and put an entry in fstab(5) so it gets mounted automatically on boot.
Same as 1, but use the noauto and user and do an explicit call to mount(1) from your application, or...
Install autofs and put an entry in auto.misc to automount the device (probably /dev/sda1) on use. Then symlink /data -> /misc/data.

Of these, I like option 3 the best, as the stick will unmount automatically when idle. Then your application need only double-check that the path is writable beforehand.

Also be super-careful on writes, as cheapie USB sticks tend to erase in large blocks and their wear levelling is weak at best (so both small random writes and large writes tend to wear the flash fast). Using f2fs or careful write buffering helps (and the noatime option on mount helps). And don't call fsync() all the time in your app!