Re: [RFD] readonly/read-write semantics

Jean-Marc Saffroy (saffroy@ri.silicomp.fr)
Tue, 4 Sep 2001 04:07:51 +0200 (CEST)


On Sat, 1 Sep 2001, Alexander Viro wrote:

> IMO a part of the problem is that we are mixing "I'm not asking that
> to be writable" with "I won't let you write". The former belongs
> to the mounting side, the latter - to filesystem.

In addition to this, I would like to be sure that a (local or remote)
file system that is not mounted r/w will not be affected by local activity
(eg. not even if I pull the power cord).

> Notice that setups along the lines "mount /dev/sda5 read-only on
> /home/jail/pub and read-write on /home/ftp/pub" are not that
> unreasonable, so even for local filesystems it might make sense.
>
> IOW, I suspect that right solution would have two separate layers -
> * does anyone get write access under that mountpoint? (VFS)
> * is this fs asked to handle write access and had it agreed with that?
> (filesystem)

Then a mount point could be compared to the notion of view in a database,
right ? Sounds nice.

-- 
Jean-Marc Saffroy - Research Engineer - Silicomp Research Institute
mailto:saffroy@ri.silicomp.fr

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