This lets userspace query whether a mountpoint was made MS_SLAVE.
Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx>
---
fs/statfs.c | 10 +++++++++-
include/linux/statfs.h | 1 +
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/statfs.c b/fs/statfs.c
index 26cda2586d7e..86e957d16a68 100644
--- a/fs/statfs.c
+++ b/fs/statfs.c
@@ -10,6 +10,7 @@
#include <linux/uaccess.h>
#include <linux/compat.h>
#include "internal.h"
+#include "pnode.h"
static int flags_by_mnt(int mnt_flags)
{
@@ -52,8 +53,15 @@ static int flags_by_sb(int s_flags)
static int calculate_f_flags(struct vfsmount *mnt)
{
- return ST_VALID | flags_by_mnt(mnt->mnt_flags) |
+ int flags = 0;
+
+ flags = ST_VALID | flags_by_mnt(mnt->mnt_flags) |
flags_by_sb(mnt->mnt_sb->s_flags);
+
+ if (IS_MNT_SLAVE(real_mount(mnt)))
+ flags |= ST_SLAVE;
+
+ return flags;
}
static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
diff --git a/include/linux/statfs.h b/include/linux/statfs.h
index 1ea4a45aa6c3..663fa5498a7d 100644
--- a/include/linux/statfs.h
+++ b/include/linux/statfs.h
@@ -42,6 +42,7 @@ struct kstatfs {
#define ST_RELATIME (1<<12) /* update atime relative to mtime/ctime */
#define ST_UNBINDABLE (1<<17) /* change to unbindable */
#define ST_PRIVATE (1<<18) /* change to private */
+#define ST_SLAVE (1<<19) /* change to slave */
#define ST_SHARED (1<<20) /* change to shared */
#endif
--
2.17.0
