soft read-only fs

[Ryan Dooley]

Hi,

I was trying to come up with a project to do and I was wondering if anybody
had done work on a filesystem to support soft read only mounts.  This is
something I had seen on our F5 Big-IP boxes.  They are based on BSD/OS for
those who are intrested.

The soft read-only functionality checks to see if files are open for writing. 
If there are none, the file system gets downgraded to read-only.  When a file
opens up for writing, the file system is promoted to read-write.

It's probably not a necessity with the more journaling filesystems that get
working with Linux.  I just wanted to make sure I wasn't about to reinvent
the wheel (or fs if you like :-)

Cheers,
	Ryan