On 05/19/2017 08:55 AM, NeilBrown wrote: > > MS_REMOUNT|MS_BIND affect all per-mount-point > flag. MS_READONLY is only special because it, > uniquely, is both a per-mount-point flag *and* a > per-filesystem flag. > > So the sections of per-mount-point flags and > MS_REMOUNT can usefully be clarified. > > Signed-off-by: NeilBrown <neilb@xxxxxxxx> Thanks, Neil. Applied. Cheers, Michael > --- > man2/mount.2 | 23 ++++++++++++++++++----- > 1 file changed, 18 insertions(+), 5 deletions(-) > > diff --git a/man2/mount.2 b/man2/mount.2 > index 35fdda084d61..3e5348368757 100644 > --- a/man2/mount.2 > +++ b/man2/mount.2 > @@ -288,6 +288,12 @@ are also settable on a per-mount-point basis. > The > .B MS_RELATIME > flag is also settable on a per-mount-point basis. > +Since Linux 2.6.16, > +.B MS_RDONLY > +can be set or cleared on a per-mount-point basis as well as on > +the underlying filesystem. The mounted filesystem will only be > +writable if neither the filesystem nor the mountpoint are flagged as > +read-only. > .\" > .SS Remounting an existing mount > An existing mount may be remounted by specifying > @@ -317,6 +323,10 @@ and > arguments should match the values used in the original > .BR mount () > call, except for those parameters that are being deliberately changed. > +Another exception is that > +.B MS_BIND > +has a different meaning for remount, and it should only be included if > +explicitly desired. > > The following > .I mountflags > @@ -351,17 +361,20 @@ then the remount operation preserves the existing values of these flags > (rather than defaulting to > .BR MS_RELATIME ). > > -Since Linux 2.6.26, this flag can also be used to make > +Since Linux 2.6.26, this flag can be used with > +.B MS_BIND > +to only modify the per-mount-point flags. > .\" See https://lwn.net/Articles/281157/ > -an existing bind mount read-only by specifying > +This is particularly useful for setting or clearing the "read-only" > +flag on a mount point without changing the underlying filesystem. > +Specifying > .IR mountflags > as: > > MS_REMOUNT | MS_BIND | MS_RDONLY > > -Note that only the > -.BR MS_RDONLY > -setting of the bind mount can be changed in this manner. > +will make access through this mountpoint read-only, without affecting > +other mount points. > .\" > .SS Creating a bind mount > If > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
