[ubifs] add update vfs super block infomation when remount to ro mode.

[ubifs] add update vfs super block infomation when remount to ro mode.

[ZhangJieJing]

If some read/write error happens(eg.CRC error), ubifs make self a read
only mode,
but the vfs infomation still not update.
This patch add this also make /proc/mounts update.

Signed-off-by: zhangjiejing <kzjeef@gmail.com>

Change-Id: I709ada21d1f6168d2e785eac389510e2b5edb2a4
---
 fs/ubifs/io.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/fs/ubifs/io.c b/fs/ubifs/io.c
index 0168271..d33c233 100644
--- a/fs/ubifs/io.c
+++ b/fs/ubifs/io.c
@@ -63,6 +63,7 @@ void ubifs_ro_mode(struct ubifs_info *c, int err)
        if (!c->ro_media) {
                c->ro_media = 1;
                c->no_chk_data_crc = 0;
+                c->vfs_sb->s_flags |= MS_RDONLY;
                ubifs_warn("switched to read-only mode, error %d", err);
                dbg_dump_stack();
        }
--
1.6.3.3
---
Best regards,
Zhang Jiejing