Messages in this thread | ![/](/images/icornerl.gif) | | From | John Bradford <> | Subject | Virtual WORM device | Date | Tue, 7 Jan 2003 18:41:07 +0000 (GMT) |
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> There is a project waiting for someone who wants > to contribute. It only slightly involves the kernel, > but is quite useful.
> Somebody should then modify `rm` and the kernel unlink > to `mv' files to the dumpster directory on the > file-system, instead of really deleting them.
Another possibility would be to create a meta-device that works like a cross between the loopback device, and WORM device, I.E. start at the begining, and allocate sectors sequentially. Whenever a sector would normally be overwritten, a new one is allocated instead. This way, you could always access the filesystem as it was at any mount in time.
Hypothetically, you could do something like:
mkmetawormdevice /dev/mw0 /dev/hda2
to create a device /dev/mw0, which uses /dev/hda2 for physical storage.
Then:
write foo to sector 0 of /dev/mw0 - actually writes foo to sector 0 of /dev/hda2
write bar to sector 1 of /dev/mw0 - actually writes foo to sector 1 of /dev/hda2
write foobar to sector 0 of /dev/mw0 - actually writes foobar to sector 2 of /dev/hda2, and notes the date and time that the virtual 'overwrite' happened.
Due to the sequential nature of the writes, the data could even be compressed quite easily.
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