doc(versioning): document version semantics of this project

It's semantic versioning applied to bcachefs kernel data structures.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

diff --git a/README.md b/README.md
index 30149ab4b72d6f6142de810c783105a0e3454ebe..f95defa55b2f9a8361d2d2d1a922169f5ac2498a 100644 (file)
--- a/README.md
+++ b/README.md
@@ -15,6 +15,16 @@ This repo primarily consists of the following:
 Please refer to the main site for [getting started](https://bcachefs.org/#Getting_started)
 An in-depth user manual is (also) found on the [official website](https://bcachefs.org/#Documentation)
 
+Version semantics
+-----------------
+
+The tools relies on an expected disk format structure which is reflected by your current kernel version.
+Disk format can be upgraded or downgraded automatically by the kernel, if needed.
+
+- Any patch-level change means no disk format change
+- Any minor-level change means a potential disk format change which **is not breaking**
+- Any major-level change means **breaking changes**
+
 Build and install
 -----------------