From f93eadd793f9f4fded30df5589f98ccfc0e1839f Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@redhat.com>
Date: Tue, 12 May 2015 16:37:56 -0700
Subject: [PATCH] mon: prevent bucket deletion when referenced by a rule

If a rule references a bucket with 'take', prevent deletion.

Fixes: #11602
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 3d591afef90b0601572c748f13faac029d05f5a0)
---
 qa/workunits/mon/crush_ops.sh |  6 ++++++
 src/crush/CrushWrapper.cc     | 27 +++++++++++++++++++++++++++
 src/crush/CrushWrapper.h      |  1 +
 3 files changed, 34 insertions(+)

diff --git a/qa/workunits/mon/crush_ops.sh b/qa/workunits/mon/crush_ops.sh
index 56a0d232d7124..847edd83c37d5 100755
--- a/qa/workunits/mon/crush_ops.sh
+++ b/qa/workunits/mon/crush_ops.sh
@@ -63,6 +63,12 @@ ceph osd tree | grep -c host1 | grep -q 0
 
 expect_false ceph osd crush rm bar   # not empty
 ceph osd crush unlink host2
+
+# reference foo and bar with a rule
+ceph osd crush rule create-simple foo-rule foo host firstn
+expect_false ceph osd crush rm foo
+ceph osd crush rule rm foo-rule
+
 ceph osd crush rm bar
 ceph osd crush rm foo
 ceph osd crush rm osd.$o2 host2
diff --git a/src/crush/CrushWrapper.cc b/src/crush/CrushWrapper.cc
index b17829b8e8ece..abf79af701f11 100644
--- a/src/crush/CrushWrapper.cc
+++ b/src/crush/CrushWrapper.cc
@@ -113,6 +113,9 @@ bool CrushWrapper::_maybe_remove_last_instance(CephContext *cct, int item, bool
   if (_search_item_exists(item)) {
     return false;
   }
+  if (item < 0 && _bucket_is_in_use(cct, item)) {
+    return false;
+  }
 
   if (item < 0 && !unlink_only) {
     crush_bucket *t = get_bucket(item);
@@ -140,6 +143,9 @@ int CrushWrapper::remove_item(CephContext *cct, int item, bool unlink_only)
 		    << " items, not empty" << dendl;
       return -ENOTEMPTY;
     }
+    if (_bucket_is_in_use(cct, item)) {
+      return -EBUSY;
+    }
   }
 
   for (int i = 0; i < crush->max_buckets; i++) {
@@ -179,6 +185,22 @@ bool CrushWrapper::_search_item_exists(int item) const
   return false;
 }
 
+bool CrushWrapper::_bucket_is_in_use(CephContext *cct, int item)
+{
+  for (unsigned i = 0; i < crush->max_rules; ++i) {
+    crush_rule *r = crush->rules[i];
+    if (!r)
+      continue;
+    for (unsigned j = 0; j < r->len; ++j) {
+      if (r->steps[j].op == CRUSH_RULE_TAKE &&
+	  r->steps[j].arg1 == item) {
+	return true;
+      }
+    }
+  }
+  return false;
+}
+
 int CrushWrapper::_remove_item_under(CephContext *cct, int item, int ancestor, bool unlink_only)
 {
   ldout(cct, 5) << "_remove_item_under " << item << " under " << ancestor
@@ -214,6 +236,11 @@ int CrushWrapper::remove_item_under(CephContext *cct, int item, int ancestor, bo
 {
   ldout(cct, 5) << "remove_item_under " << item << " under " << ancestor
 		<< (unlink_only ? " unlink_only":"") << dendl;
+
+  if (!unlink_only && _bucket_is_in_use(cct, item)) {
+    return -EBUSY;
+  }
+
   int ret = _remove_item_under(cct, item, ancestor, unlink_only);
   if (ret < 0)
     return ret;
diff --git a/src/crush/CrushWrapper.h b/src/crush/CrushWrapper.h
index 9fac2fe443ab6..8e285976dd493 100644
--- a/src/crush/CrushWrapper.h
+++ b/src/crush/CrushWrapper.h
@@ -518,6 +518,7 @@ public:
 private:
   bool _maybe_remove_last_instance(CephContext *cct, int id, bool unlink_only);
   int _remove_item_under(CephContext *cct, int id, int ancestor, bool unlink_only);
+  bool _bucket_is_in_use(CephContext *cct, int id);
 public:
   int remove_item_under(CephContext *cct, int id, int ancestor, bool unlink_only);
 
-- 
2.39.5