On Tue, Dec 05, 2006 at 11:41:28AM -0500, Nikolai Joukov wrote: > > > As we promised on the linux-ext4 list on October 31, here is the patch > > > that adds secure deletion via a trash-bin functionality for ext4. It is a > > > compromise solution that combines secure deletion with the trash-bin support > > > (the latter had been requested by even more people than the former :-). > > > > Given that almost all of the code for this uses vfs interfaces and > > only a couple of simple filesystem hooks, is there any reason for > > this being ext4 specific? i.e. why aren't you hooking the vfs layer > > so we get a single undelete/secure delete implementation for all > > filesystems? > > You are right. Actually, we mentioned it as a benefit number 4 of this > approach in the original post. Most of the code is not > file-system--specific and can be used by any other (all other?) file > system(s). The only complication is that only ext2/3/4 and reiser file > systems already support the per-file secure deletion and undelete > attributes. They are defined but unused in 2.6.19, right? I can't see anywhere in the 2.6.19 ext2/3/4/reiser trees that actually those flags, including setting and retrieving them from disk. JFS i can see sets, clears and retreives them, but not the fielsystems you mention. Though I might just be blind..... ;) If all we need to add to XFS is support for those flags, then XFS support would be trivial to add. Oh, damn. I take that back. We're almost out of flag space in the on disk inode - these two flags would use the last 2 flag bits so this may require an on disk inode format change in XFS. This will be a little more complex than I first thought, but not impossible as we already support two on-disk inode format versions. > Since ext4 is in early development now, we believe it'd be easier to get > such code into ext4 than into the main-line VFS. If there's enough > interested among the kernel maintainers, we'd be happy to move this > functionality to the VFS and provide f/s hooks for > secure-deletion/trash-bin. I'd certainly like to see new functionality like this added at the VFS rather than in any particular filesystem. Don't know about anyone else, though.... > I guess, the right thing to do would be to move the common trash-bin > (tb.c and tb.h) code into the /fs and /include/linux directories. And call them trashbin.[ch] ;) > Also, VFS would require just a couple of trivial changes to support > something like '-o trashbin' mount-time option for all file systems. > In addition, individual file systems may support per-file attributes for > this (e.g., ext2/3/4). Sounds like a good idea to me. Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
