From 356231bc2a8bbc640f1375f39f985ec2e6d939e0 Mon Sep 17 00:00:00 2001
From: Axel Burri <axel@tty0.ch>
Date: Sat, 29 Jul 2017 19:03:23 +0200
Subject: [PATCH] btrbk: abort if source subvolume has readonly or
 received_uuid flag

---
 ChangeLog  |  2 ++
 btrbk      | 10 ++++++++++
 doc/FAQ.md | 18 ++++++++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 6f42d21..d824dab 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,6 +5,8 @@ btrbk-current
     and "lockfile" configuration options.
   * Show "up-to-date" status for backups in "stats" command.
   * Show "correlated" status instead of "orphaned" in "stats" command.
+  * Check source subvolumes for readonly and received_uuid flags, and
+    abort if one of them is set.
 
 btrbk-0.25.0
 
diff --git a/btrbk b/btrbk
index 590c230..d814836 100755
--- a/btrbk
+++ b/btrbk
@@ -4534,6 +4534,16 @@ MAIN:
         WARN "Skipping subvolume \"$svol->{PRINT}\": $abrt";
         next;
       }
+      if($svol->{node}{readonly}) {
+        ABORTED($svol, "subvolume is readonly");
+        WARN "Skipping subvolume \"$svol->{PRINT}\": $abrt";
+        next;
+      }
+      if($svol->{node}{received_uuid} ne '-') {
+        ABORTED($svol, "\"Received UUID\" is set");
+        WARN "Skipping subvolume \"$svol->{PRINT}\": $abrt";
+        next;
+      }
       if($svol->{node}{uuid} && _is_child_of($sroot->{node}, $svol->{node}{uuid})) {
         DEBUG "Found \"$svol->{PRINT}\" (id=$svol->{node}{id}) in btrfs subtree of: $sroot->{PRINT}";
       } else {
diff --git a/doc/FAQ.md b/doc/FAQ.md
index 8f84b6b..0f62a07 100644
--- a/doc/FAQ.md
+++ b/doc/FAQ.md
@@ -260,3 +260,21 @@ This approach has the advantage that you don't need to reformat your
 USB disk. This works fine, but be aware that you may run into trouble
 if a single stream gets corrupted, making all subsequent streams
 unusable.
+
+
+I'm getting an error: Aborted: "Received UUID" is set
+-----------------------------------------------------
+
+You probably restored a backup with send-receive, and made it
+read/write using `btrfs property set`. This is bad, as all snapshots
+and backups will inherit this identical "Received UUID", which results
+in all these subvolumes will be treated as "containing same data".
+
+To fix this, create a "proper" snapshot:
+
+    # cd /mnt/btr_pool
+    # mv mysubvolume mysubvolume.broken
+    # btrfs subvolume snapshot mysubvolume.broken mysubvolume
+
+Now, `mysubvolume` should have an empty "Received UUID", and btrbk
+will not complain any more.