Fwd: Bug#838958: linux: mount(2) _silently_ ignores other mountflags when MS_BIND is set
tags 838958 fixed-upstream
thanks
On 09/27/2016 11:27 AM, Debian Bug Tracking System wrote:
> Processing control commands:
>
>> reassign -1 manpages-dev
> Bug #838958 [src:linux] linux: mount(2) _silently_ ignores other mountflags when MS_BIND is set
> Bug reassigned from package 'src:linux' to 'manpages-dev'.
> Ignoring request to alter found versions of bug #838958 to the same values previously set
> Ignoring request to alter fixed versions of bug #838958 to the same values previously set
By chance, in the most recent upstream release (4.07) I made substantial
changes to the mount(2) page:
http://man7.org/linux/man-pages/man2/mount.2.html
In particular, I think the following new text addresses the doc problem
relevant to this bug:
Creating a bind mount
If mountflags includes MS_BIND (available since Linux 2.4), then
perform a bind mount. A bind mount makes a file or a directory
subtree visible at another point within the single directory
hierarchy. Bind mounts may cross filesystem boundaries and span
chroot(2) jails.
The filesystemtype and data arguments are ignored.
The remaining bits in the mountflags argument are also ignored, with
the exception of MS_REC. (The bind mount has the same mount options
as the underlying mount point.) However, see the discussion of
remounting above, for a method of making an existing bind mount read-
only.
And the referred-to text describing MS_REMOUNT nowadays says:
Since Linux 2.6.26, this flag can also be used to make an existing
bind mount read-only by specifying mountflags as:
MS_REMOUNT | MS_BIND | MS_RDONLY
Note that only the MS_RDONLY setting of the bind mount can be changed
in this manner.
Cheers,
Michael
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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