[Bugs] [Bug 1297182] Mounting with "-o noatime" or "-o noexec" causes "nosuid, nodev" to be set as well

[bugzilla at redhat.com]

https://bugzilla.redhat.com/show_bug.cgi?id=1297182



--- Comment #16 from Worker Ant <bugzilla-bot at gluster.org> ---
COMMIT: https://review.gluster.org/16313 committed in master by Kaleb KEITHLEY
(kkeithle at redhat.com) 
------
commit e624e7fe38a784363c57108c73487d83a7bda562
Author: Csaba Henk <csaba at redhat.com>
Date:   Tue Jan 3 15:26:30 2017 +0100

    fuse: clean up mount flag processing

    In general, when one invokes a mount helper program -- basically
    anything that mounts something based on its command line, so thinking of
    mount(8), mount.<fs-type> or fusermount, but also of FUSE servers in
    general, including glusterfs -- the command line arguments that are to
    affect mount(2) are mapped to a bitmask called the mount flags, which is
    passed to mount(2), so that the kernel can interpret the flag bits and
    adjusts properties of the mount accordingly.

    There is a traditional syntax for this mechanism as implemented in
    mount(8): one passes "-ocomma,separated,mount,options" and the
    individual option name strings are mapped to flag bits in mount(8).

    FUSE further explores this idea and typically the FUSE server command
    lines allow further option names to be used in the "-ooption,name,list"
    which are then separated from the kernel sanctioned option names (to
    which we'll refer as "system mount options") and are passed to a
    platform specific lower level fuse mount helper interface.

    The separation of system mount option names and FUSE specific option
    names is also platform specific, so the general mount interface
    function, which in case of glusterfs is gf_fuse_mount(), should abstract
    this away.

    Therefore we change the signature of this function from

            int gf_fuse_mount (const char *mountpoint, char *fsname,
                               unsigned long mountflags, char *mnt_param,
                               pid_t *mtab_pid, int status_fd);

    to

            int gf_fuse_mount (const char *mountpoint, char *fsname,
                               char *mnt_param, pid_t *mtab_pid,
                               int status_fd);

    and deal with flag extraction in platform specific mount code. Note that
    the sole purpose of the mountflags argument was to indicate read-only
    mounting. The other system mount option names were expected to reside in
    the comma-separated mnt_param string, but they were not properly
    processed (see the referred BUG). With the new gf_fuse_mount signature
    read-only mounting is to be indicated as a "ro" component in mnt_param.

    - For Darwin, which has a dedicated, separate gf_fuse_mount
      implementation, gf_fuse_mount was ignoring mountflags, so only the
      signature had to to be adjusted. However, as bonus, we gain read-only
      support for Darwin, which was missing so far, given that it was
      indicated via the ignored mountflags. Darwin's low level mount helper
      relies on the "ro" component of the option string, which agrees with
      the new calling convention of gf_fuse_mount.

    - On Linux, system mount option name handling (apart from the
      distinguished read-only option) used to have the inadvertent side
      effect of adding "nosuid,nodev" as indicated in BUG; since
      Ia89d975d1e27fcfa5ab2036ba546aa8fa0d2d1b0 this side effect is removed,
      but system mount option name handling was left broken (passing system
      mount options other than "ro" fails to mount).

    - On other platforms, system mount option name handling is broken
      (expect for the distinguished read-only option).

    As of this change, in the general (non-Darwin) implementation of
    gf_fuse_mount we take care of proper separation of system mount names
    and their conversion to mount flags. For Linux, we adopt the conversion
    table from FUSE upstream. For other systems we just provide a best
    effort to support those system mount options which are understood across
    all Unices (nosuid,nodev,noatime,noexec,ro). (This can be improved later
    to provide proper plaform support.)

    BUG: 1297182
    Change-Id: I5d10b5df46feba7a02bf5bf1018db69e6b52260a
    Signed-off-by: Csaba Henk <csaba at redhat.com>
    Reviewed-on: https://review.gluster.org/16313
    Smoke: Gluster Build System <jenkins at build.gluster.org>
    NetBSD-regression: NetBSD Build System <jenkins at build.gluster.org>
    CentOS-regression: Gluster Build System <jenkins at build.gluster.org>
    Reviewed-by: Amar Tumballi <amarts at redhat.com>
    Tested-by: Amar Tumballi <amarts at redhat.com>

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