• David Howells's avatar
    VFS: Differentiate mount flags (MS_*) from internal superblock flags · e462ec50
    David Howells authored
    Differentiate the MS_* flags passed to mount(2) from the internal flags set
    in the super_block's s_flags.  s_flags are now called SB_*, with the names
    and the values for the moment mirroring the MS_* flags that they're
    equivalent to.
    
    In this patch, just the headers are altered and some kernel code where
    blind automated conversion isn't necessarily correct.
    
    Note that this shows up some interesting issues:
    
     (1) Some MS_* flags get translated to MNT_* flags (such as MS_NODEV ->
         MNT_NODEV) without passing this on to the filesystem, but some
         filesystems set such flags anyway.
    
     (2) The ->remount_fs() methods of some filesystems adjust the *flags
         argument by setting MS_* flags in it, such as MS_NOATIME - but these
         flags are then scrubbed by do_remount_sb() (only the occupants of
         MS_RMT_MASK are permitted: MS_RDONLY, MS_SYNCHRONOUS, MS_MANDLOCK,
         MS_I_VERSION and MS_LAZYTIME)
    
    I'm not sure what's the best way to solve all these cases.
    Suggested-by: 's avatarAl Viro <viro@ZenIV.linux.org.uk>
    Signed-off-by: 's avatarDavid Howells <dhowells@redhat.com>
    e462ec50
do_mounts.c 14.6 KB