Messages in this thread | | | From | "Stefan Monnier" <monnier+lists/linux/kernel/news/@tequila.cs.yale.edu> | Subject | Re: FS Unions | Date | 15 Jun 1999 12:16:46 -0400 |
| |
>>>>> "Jan-Simon" == Jan-Simon Pendry <jsp@ms.com> writes: > 1. persistent representation of a whiteout node. > 2. persistently mark a directory non-transparent. > 3. return list of whiteouts in a directory. > 4. create a named whiteout. > 5. remove a named whiteout.
This intrusiveness is very bothersome. How about a different model where the unionfs is really just a file-system that unions two others (i.e. a total of 3 filesystems involved). This way, all the white-out garbage can be kept in unionfs. Also the `move directory' could potentially be dealt with by having the unionfs layer remember the move (basically, unionfs would be a layer of redirection-pointers that originally either point to a same-name node in fs1 or a same-name node in fs2, and over time that would change by adding pointers to nowhereland (white-outs) and pointers to different-name nodes in fs[12].
Of course, it might be better to make those redirection-pointers point to several places at a time (if those places a re directories).
To provide persistence, the unionfs would of course need some disk space, which would probably be a file rather than a partition.
Write access would either be disallowed, or would be applied to one of the underlying filesystems. Unless we want to make unionfs a full-blown filesystem so that you can write to it and create files directly in it.
Stefan
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |