On Sun, Oct 28, 2007 at 07:00:22PM -0400, Bernardo Innocenti wrote:
> These two defines happen to have the same value (128 or 0x80) in
> mount/mount_constants.h.
>
> From a quick scan, it seems there's no immediate harm in it, but
> it's still very confusing.
Hmm...
util-linux 2.10n:
* mount: add replace, after, before, over, bind
Why there is undocumented mount options
--after|--before|--over|--replace ?
in mount/mount_constants.h:
#ifndef MS_ACTION_MASK
#define MS_ACTION_MASK 0x380
/* Remount, but new filesystem may be different from old. Atomic
(i.e. there is no interval when nothing is mounted at the mountpoint).
If new fs differs from the old one and old is busy - -EBUSY. */
#define MS_REPLACE 0x080 /* 128 */
/* After, Before: as soon as we get unions these will add a new member
in the end or beginning of the chain. Fail if there is a stack
on the mountpoint. */
#define MS_AFTER 0x100 /* 256 */
#define MS_BEFORE 0x180
/* Over: if nothing mounted on a mountpoint - same as if none of these
flags had been set; if we have a union with more than one element - fail;
if we have a stack or plain mount - mount atop of it, forming a stack. */
#define MS_OVER 0x200 /* 512 */
#endif
I don't see MS_{REPLACE,AFTER,BEFORE,OVER} in linux-2.6/include/linux/fs.h.
Is it unimplemented stuff? If yes, I'd like to remove it mount(8).
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
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