ramfs: Keep track of attribute indexed state better and add assertions.

The "ASSERT(!fInIndex || fInIndex != inIndex);" one, tracking
state transitions, catches the underlying cause of #19252.

src/add-ons/kernel/file_systems/ramfs/Attribute.cpp

@@ -26,6 +26,7 @@ Attribute::Attribute(Volume *volume, Node *node, const char *name,
 // destructor
 Attribute::~Attribute()
 {
+	ASSERT(fIndex == NULL);
 }
 
 // InitCheck
@@ -101,6 +102,9 @@ Attribute::WriteAt(off_t offset, const void *buffer, size_t size,
 void
 Attribute::SetIndex(AttributeIndex *index, bool inIndex)
 {
+	ASSERT(fIndex == NULL || index == NULL || fIndex == index);
+	ASSERT(!fInIndex || fInIndex != inIndex);
+
 	fIndex = index;
 	fInIndex = inIndex;
 }

src/add-ons/kernel/file_systems/ramfs/AttributeIndexImpl.cpp

@@ -237,8 +237,7 @@ AttributeIndexImpl::CountEntries() const
 
 // Changed
 status_t
-AttributeIndexImpl::Changed(Attribute *attribute, const uint8 *oldKey,
-							size_t oldLength)
+AttributeIndexImpl::Changed(Attribute *attribute, const uint8 *oldKey, size_t oldLength)
 {
 	fVolume->AssertWriteLocked();
 
@@ -261,17 +260,16 @@ AttributeIndexImpl::Changed(Attribute *attribute, const uint8 *oldKey,
 				}
 				// remove and re-insert the attribute
 				it.Remove();
+				attribute->SetIndex(this, false);
 			}
 		}
 		// re-insert the attribute
 		if (fKeyLength > 0 && attribute->GetSize() != (off_t)fKeyLength) {
-			attribute->SetIndex(this, false);
+			ASSERT(!attribute->IsInIndex());
 		} else {
 			error = fAttributes->Insert(attribute);
 			if (error == B_OK)
 				attribute->SetIndex(this, true);
-			else
-				attribute->SetIndex(NULL, false);
 		}
 	}
 	return error;
@@ -281,7 +279,9 @@ AttributeIndexImpl::Changed(Attribute *attribute, const uint8 *oldKey,
 status_t
 AttributeIndexImpl::Added(Attribute *attribute)
 {
-PRINT("AttributeIndex::Add(%p)\n", attribute);
+	PRINT("AttributeIndex::Add(%p)\n", attribute);
+	fVolume->AssertWriteLocked();
+
 	status_t error = (attribute ? B_OK : B_BAD_VALUE);
 	if (error == B_OK) {
 		size_t size = attribute->GetSize();
@@ -300,13 +300,17 @@ PRINT("AttributeIndex::Add(%p)\n", attribute);
 bool
 AttributeIndexImpl::Removed(Attribute *attribute)
 {
-PRINT("AttributeIndex::Removed(%p)\n", attribute);
-	bool result = (attribute && attribute->GetIndex() == this);
-	if (result) {
-		if (attribute->IsInIndex())
-			fAttributes->Remove(attribute, attribute);
+	PRINT("AttributeIndex::Removed(%p)\n", attribute);
+	fVolume->AssertWriteLocked();
+
+	if (attribute == NULL || attribute->GetIndex() != this)
+		return false;
+
+	bool result = true;
+	if (attribute->IsInIndex())
+		result = (fAttributes->Remove(attribute, attribute) == B_OK);
+	if (result)
 		attribute->SetIndex(NULL, false);
-	}
 	return result;
 }