sync_filesystem() does not sync dirty data for readonly
filesystem during umount, so before changing to readonly
filesystem we should sync dirty data for data integrity.
Signed-off-by: Chengguang Xu <cgxu519@xxxxxxxxxxxx>
---
fs/overlayfs/super.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index f57aa348dcd6..1bab326342bc 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -364,11 +364,20 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
static int ovl_remount(struct super_block *sb, int *flags, char *data)
{
struct ovl_fs *ofs = sb->s_fs_info;
+ struct super_block *upper_sb;
+ int ret = 0;
if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs))
return -EROFS;
- return 0;
+ if (*flags & SB_RDONLY && !sb_rdonly(sb)) {
+ upper_sb = ofs->upper_mnt->mnt_sb;
+ down_read(&upper_sb->s_umount);
+ ret = sync_filesystem(upper_sb);
+ up_read(&upper_sb->s_umount);
+ }
+
+ return ret;
}
static const struct super_operations ovl_super_operations = {
--
2.20.1
