Re: [PATCH] cramfs is ro only, so honour this in inode->mode

Shane Nay (shane@agendacomputing.com)
Mon, 8 Jan 2001 12:13:39 +0000


Ingo,
> cramfs is a read-only fs. So we should honour that in inode->mode
> to avoid confusion of programs.
>
> My isofs shows this too, so I think I'm right deleting the write
> permissions in the inode. May be we should change it in
> mkcramfs (too).
>
> I don't know what POSIX says about RO fs, but I can't find any
> real sense in having W permissions for an RO fs.

The only sense I can derive from it is the situation that I'm in. We use
cramfs partitions for lots of stuff, but one of them is to hold mirrors of
the "default" configuration of the user-area of our device. (Flash) It
makes it easy to just copy over the base partitions knowing the permisions
will stick right.

This may not initially seem like such a great thing..., but imagine a base
distro being distributed as a cramfs file. Copy the thing over to your HD
and you're done, otherwise the distro packaging has to keep track of
permisions for each file, etc.

On the other hand..., maybe I'm being "selfish", and this is the right way to
go. You never write to it, so why track the write bits? (One answer is
maybe later we can create a writable cramfs, but oh well) Lord knows I could
use a few extra bits in the cramfs inode.... (Using sticky bit to denote XIP
mode binaries right now..., such a hack)

Thanks,
Shane Nay.
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