Re: How to export linux fs using USB MassStorage device


Well it sounds easy as you write it, but creating a fat in the
background - at least some caching for the most important structures
is required - and give the right block - created on the fly - back
when asked for the block number seems not an easy task to me.

I don't see what you mean here. For a read-only thingy you don't "create ab fat in the background", but you simulate one. You provide the PC with a completely constant file-system definition and FAT (only one is necessary) and a directory that only is dynamic regarding the file site. Now the PC will request blocks with the files' content according to the FAT information you provided. Your program will read these blocks from the real files-


So I plan to first create a few simple things as user apps:
- simple static fat which can be mounted using a loop device

I don't see why you need a loop device - or anything additional to the modified g_file software at all.

- simple app read a directory structure, convert it into static fat,
mountable using loop

???


Now write a simple block device driver (module) which builds upppon
simple app 2
challenges here might be:
- access directory using vfs access inside the kernel instead of user
space
- get the blocks dynamicly created
This block device should be mountable as fat

If that is done I only need to load g_file_storage with the device
- sounds easy ... right ^^

To me that sounds rather complicated (compared to just modifying the g_file program to simulate an FAT device for the PC.

-Michael
.