On Fri, Feb 11, 2005 at 01:58:59PM -0500, Gregory Maxwell wrote: > 1. Lots of applications today (such a P2P sharing systems) need the > hashes of files.. it's inefficient to keep recomputing them. The file > system always knows when a file changes, so it can be setup to always > return the correct hash.
That should be done in userland, imho. Especially since different apps use lots of different hashes. I was thinking about this kind of stuff (ECC plugin for r4) not too long ago. Hashing the whole file is too slow; if you update a single block, the whole file has to be read in to recalculate. Adding, say, one sector of crc for each block would be a lot more feasible. I think the best way to do this though, would be to write a virtual blk driver that works like loop back (ie, uses a backing file/dev), and shortens the overall size by one sector * number of blocks. Actually, you could probably copy the raid5 md code and rewrite it to only use one device. I'd try that first. -- Tom Vier <[EMAIL PROTECTED]> DSA Key ID 0x15741ECE
