@@ -21,12 +21,19 @@ from accessing the corresponding object from the original filesystem.
This is most obvious from the 'st_dev' field returned by stat(2).
While directories will report an st_dev from the overlay-filesystem,
-all non-directory objects will report an st_dev from the lower or
+non-directory objects may report an st_dev from the lower filesystem or
upper filesystem that is providing the object. Similarly st_ino will
only be unique when combined with st_dev, and both of these can change
over the lifetime of a non-directory object. Many applications and
tools ignore these values and will not be affected.
+In the special case of all overlay layers on the same underlying
+filesystem, all objects will report an st_dev from the overlay
+filesystem and st_ino from the underlying filesystem. This will
+make the overlay mount more compliant with filesystem scanners and
+overlay objects will be distinguishable from the corresponding
+objects in the original filesystem.
+
Upper and Lower
---------------
Signed-off-by: Amir Goldstein <amir73il@gmail.com> --- Documentation/filesystems/overlayfs.txt | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)