On Thu, 2017-06-29 at 11:25 +0200, Carlos Maiolino wrote: > Emergency remount (sysrq-u) sets MS_RDONLY to the superblock but doesn't set > MNT_READONLY to the mount point. > > Once calculate_f_flags() only check for the mount point read only state, > when setting kstatfs flags, after an emergency remount, statfs does not > report the filesystem as read-only, even though it is. > > Enable flags_by_sb() to also check for superblock read only state, so the > kstatfs and consequently statfs can properly show the read-only state of > the filesystem. > > Signed-off-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx> > --- > fs/statfs.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/fs/statfs.c b/fs/statfs.c > index 4e4623c..c1dfc37 100644 > --- a/fs/statfs.c > +++ b/fs/statfs.c > @@ -38,6 +38,8 @@ static int flags_by_sb(int s_flags) > flags |= ST_SYNCHRONOUS; > if (s_flags & MS_MANDLOCK) > flags |= ST_MANDLOCK; > + if (s_flags & MS_RDONLY) > + flags |= ST_RDONLY; > return flags; > } > IIUC, the superblock won't be writeable once MS_RDONLY is set, so every mount that uses it also becomes readonly regardless of how MNT_READONLY is set. LGTM: Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
