Re: [PATCH v11 21/48] ext4: Add richacl feature flag

On Mon, Oct 19, 2015 at 3:16 PM, Austin S Hemmelgarn
[off-list ref] wrote:

On 2015-10-16 13:41, Andreas Gruenbacher wrote:

quoted

On Fri, Oct 16, 2015 at 7:31 PM, Austin S Hemmelgarn
[off-list ref] wrote:

quoted

I would like to re-iterate, on both XFS and ext4, I _really_ think this
should be a ro_compat flag, and not an incompat one.  If a person has the
ability to mount the FS (even if it's a read-only mount), then they by
definition have read access to the file or partition that the filesystem
is contained in, which means that any ACL's stored on the filesystem are
functionally irrelevant,

It is unfortunately not safe to make such a file system accessible to
other users, so the feature is not strictly read-only compatible.

OK, seeing as I wasn't particularly clear as to why I object to this in my
other e-mail, let's try this again.

Can you please explain exactly why it isn't safe to make such a filesystem
accessible to other users?

See here: http://www.spinics.net/lists/linux-ext4/msg49541.html

Andreas