Re: [PATCH] ntfs: compare streams_interface with mounted volume on remount

[CharSyam]

Hi liubaolin.

Thanks for your reviews.
I will fix it soon.

2026년 10월 12일 (월) 오후 5:26, liubaolin <liubaolin12138@xxxxxxx>님이 작성:
>
>
>
> 在 2026/10/12 11:16, DaeMyung Kang 写道:
> > During reconfiguration, fc->s_fs_info points to a newly allocated
> > ntfs_volume. It does not contain the mounted volume's stream setting.
> > Consequently, a windows mount rejects a remount with the same
> > streams_interface=windows setting, but accepts streams_interface=none
> > without changing the active pathname interface. This also breaks an
> > ordinary read-only remount when the existing windows setting is passed
> > again, for example from fstab.
> >
> > Compare the requested setting with the mounted volume instead. Use its
> > superblock when reporting an unsupported setting change.
> >
> > Fixes: 2de2cdd9cc08 ("ntfs: add pathname access for named streams")
> > Signed-off-by: DaeMyung Kang <charsyam@xxxxxxxxx>
> > ---
> >   fs/ntfs/super.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
> > index 242fb19ced2b..711e90be9382 100644
> > --- a/fs/ntfs/super.c
> > +++ b/fs/ntfs/super.c
> > @@ -275,8 +275,8 @@ static int ntfs_parse_param(struct fs_context *fc, struct fs_parameter *param)
> >                       result.uint_32 == STREAMS_INTERFACE_WINDOWS;
> >
> >               if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE &&
> > -                 NVolStreamsWindows(vol) != streams_windows) {
> > -                     ntfs_error(vol->sb,
> > +                 NVolStreamsWindows(NTFS_SB(fc->root->d_sb)) != streams_windows) {
> > +                     ntfs_error(fc->root->d_sb,
> >                                  "Cannot change streams_interface on remount.");
> >                       return -EINVAL;
> >               }
>
> Hi DaeMyung,
>
>     The fix looks correct.
>     However, vol->sb is NULL in the newly allocated volume, so
> ntfs_error() only logs the message. Changing the argument to
> fc->root->d_sb also invokes the mounted volume’s error-handling policy,
> which would trigger a panic on a read-write mount with errors=panic.
>
>     This branch only rejects an unsupported option change during
> remount; it does not indicate filesystem corruption or an I/O error.
>
>     Could we use ntfs_warning(fc->root->d_sb, ...) without triggering
> that policy?
>
> Thanks,
> Baolin.
>