• Miklos Szeredi's avatar
    ovl: mount read-only if workdir can't be created · cc6f67bc
    Miklos Szeredi authored
    OpenWRT folks reported that overlayfs fails to mount if upper fs is full,
    because workdir can't be created.  Wordir creation can fail for various
    other reasons too.
    
    There's no reason that the mount itself should fail, overlayfs can work
    fine without a workdir, as long as the overlay isn't modified.
    
    So mount it read-only and don't allow remounting read-write.
    
    Add a couple of WARN_ON()s for the impossible case of workdir being used
    despite being read-only.
    
    Reported-by: Bastian Bittorf <bittorf@bluebottle.com> 
    Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
    Cc: <stable@vger.kernel.org> # v3.18+
    cc6f67bc
dir.c 21.3 KB