On Tue, Jan 16, 2018 at 10:10:12AM +0000, David Howells wrote:
> Inside the kernel the MS_* flags appear to belong to a number of fundamentally
> different classes:
Good point, but I'm not sure about your terminology -- for example
"topology" sounds strange if we use "propagation" for years.
> (1) Things like MS_SILENT and MS_REMOUNT which affect the behaviour of the
> mount process, but aren't persistent beyond that.
mount-operation flags (now including MS_BIND too)
> (2) Inter-namespace topology management, controlling how mounts are shared
> and duplicated between namespaces.
propagation flags
> (3) Restrictions on accesses through a particular mountpoint, eg. MS_NODEV,
> MS_NOEXEC.
VFS flags (now including MS_BIND|MS_REMOUNT|MS_RDONLY too)
> (4) Instructions to a filesystem on how a superblock is to behave.
FS flags
> I think the classes are fundamentally different - and we've already separated
> (4) from the others inside the kernel. However, I've no great objection to
> keeping (2) and (3) together in the same mask. It just sounds cleaner to
> separate them.
I agree.
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
