diff mbox series

[06/24] fs: add is_userns_visible() helper

Message ID 20200211165753.356508-7-christian.brauner@ubuntu.com (mailing list archive)
State New, archived
Headers show
Series user_namespace: introduce fsid mappings | expand

Commit Message

Christian Brauner Feb. 11, 2020, 4:57 p.m. UTC 
Introduce a helper which makes it possible to detect fileystems whose
superblock is visible in multiple user namespace. This currently only
means proc and sys. Such filesystems usually have special semantics so their
behavior will not be changed with the introduction of fsid mappings.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
---
 include/linux/fs.h | 5 +++++
 1 file changed, 5 insertions(+)
diff mbox series

Patch

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 98e0349adb52..1449cd363fb6 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3627,4 +3627,9 @@  static inline int inode_drain_writes(struct inode *inode)
 	return filemap_write_and_wait(inode->i_mapping);
 }
 
+static inline bool is_userns_visible(unsigned long iflags)
+{
+	return (iflags & SB_I_USERNS_VISIBLE);
+}
+
 #endif /* _LINUX_FS_H */