Re: removable media revalidation - udev vs. devfs or static /dev

Linus Torvalds
2004-01-08T02:03:44Z

On Wed, 7 Jan 2004, Olaf Hering wrote:
> >
> > Then, user space can just access "/dev/sda1" or whatever, and the act of
> > accessing it will force the re-scan.
>
> How would that work? I mean, what will a tool that cares about a block
> event do? It will run a fdisk/parted -l /udev/sda to figure out what partitions
> are there (just to skip an extended partition sda5, as example) and
> finds no media. That tool will never run again on sda, unless a new
> block add event comes in. So some sort of polling is required for that
> class of devices.

What is your problem?

I'll use a very common and simple case that I do myself: use any USB media
reader to read a camera card. It will be a FAT filesystem on the first
partition, so your fstab might look like this:

/dev/sda1 /mnt/smartmedia vfat noauto,user,ro 0 0

and then you just do "mount /mnt/smartmedia", and you're done.

This works. I do it all the time. You just stick in your card, and mount
it, and off it foes. No "fdisk" or "parted" _anywhere_.

Linus