From 0a93f6913570b4019d18b7eb7ded5110b2b1d19e Mon Sep 17 00:00:00 2001
From: Axel Burri <axel@tty0.ch>
Date: Thu, 11 Apr 2019 14:41:08 +0200
Subject: [PATCH] btrbk: treat all related readonly subvolumes within snapdir
 as "snapshots"

With this, previous snapshots (far relations) are still listed when
restoring a snapshot.

Example (S = source subvolume, readwrite):

  After 3 snapshots:
  A->S, B->S, C->S

  Restore B: `btrfs subvol delete S; btrfs subvol snapshot B S'`
  A->S, B->S, C->S, S'->B

Previous implementation would show now snapshots for S', as no
snapshot has parent_uuid=S'.

New implementation shows A, B, C as snapshots for S', as orphaned
siblings (A, B, C pointing to deleted S) are also related.
---
 btrbk | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/btrbk b/btrbk
index b9e6030..8c5265a 100755
--- a/btrbk
+++ b/btrbk
@@ -2920,14 +2920,11 @@ sub get_snapshot_children($$;$)
   my $snaproot = shift || die;
   my $svol = shift // die;
   my $btrbk_basename = shift; # if set, also filter by direct_leaf
-  my @ret;
+  my @ret = map( { vinfo_resolved($_, $snaproot, btrbk_direct_leaf => $btrbk_basename) // () }
+                 @{get_related_readonly_nodes($svol)} );
 
-  foreach (@{vinfo_subvol_list($snaproot, readonly => 1, btrbk_direct_leaf => $btrbk_basename)}) {
-    next unless($_->{node}{parent_uuid} eq $svol->{node}{uuid});
-    TRACE "get_snapshot_children: found: $_->{PRINT}";
-    push(@ret, $_);
-  }
-  DEBUG "Found " . scalar(@ret) . " snapshot children of \"$svol->{PRINT}\" in: $snaproot->{PRINT}" . (defined($btrbk_basename) ? "/$btrbk_basename.*" : "");
+  if($loglevel >= 4) { TRACE "get_snapshot_children: found: $_->{PRINT}" foreach(@ret); }
+  DEBUG "Found " . scalar(@ret) . " related snapshots of \"$svol->{PRINT}\" in: $snaproot->{PRINT}" . (defined($btrbk_basename) ? "/$btrbk_basename.*" : "");
   return @ret;
 }