[SMB3POSIX] File attributes

[Jeremy Allison]

On Tue, Nov 28, 2023 at 05:32:48PM -0600, Steve French wrote:
>
>Couldn't we implement "chattr +i" ("immutable") by updating the ACL? Or if
>the ACL solution is not good enough (e.g. preventing links to be created to
>the
>file etc.) then seems like no harm in defining an ioctl as a secondary way
>to set the following attrs:
>
>#define STATX_ATTR_COMPRESSED           0x00000004 /* [I] File is
>compressed by the fs */
>#define STATX_ATTR_IMMUTABLE            0x00000010 /* [I] File is marked
>immutable */
>#define STATX_ATTR_APPEND               0x00000020 /* [I] File is
>append-only */
>#define STATX_ATTR_NODUMP               0x00000040 /* [I] File is not to be
>dumped */
>#define STATX_ATTR_ENCRYPTED            0x00000800 /* [I] File requires key
>to decrypt in fs */
>#define STATX_ATTR_AUTOMOUNT            0x00001000 /* Dir: Automount
>trigger */
>#define STATX_ATTR_MOUNT_ROOT           0x00002000 /* Root of a mount */
>#define STATX_ATTR_VERITY               0x00100000 /* [I] Verity protected
>file */
>#define STATX_ATTR_DAX                  0x00200000 /* File is currently in
>DAX state */

I disagree. There is harm in specifying something which
currently has no users or usage. We don't want to add
arbitrary stuff that isn't currently used or needed,
that way lies the SMB1+POSIX extensions - which
defined a chattr but was never implemented on Linux.

We might get it wrong.

Let's start with a minimum usable feature set that
people actually use, and once we have more experience
with that then let's *carefully* decide if we want/need
to expand it.