From 4a2b112e98fe4c66f805eb690bfe1ae7ba342e5b Mon Sep 17 00:00:00 2001
From: Ming-Hung Tsai <mtsai@redhat.com>
Date: Thu, 19 Aug 2021 18:38:23 +0800
Subject: [PATCH 2/3] [thin_repair/thin_dump] Change the label type for empty
leaves
Empty leaves now are treated as bottom-level leaves, so that empty
devices could be recovered.
(cherry picked from commit d3f796f5e35162b0867ee2ba8de781f14ad35c61)
---
functional-tests/thin-functional-tests.scm | 53 +++++++++++++++++++++++++++++-
thin-provisioning/metadata_dumper.cc | 8 +++++
2 files changed, 60 insertions(+), 1 deletion(-)
diff --git a/functional-tests/thin-functional-tests.scm b/functional-tests/thin-functional-tests.scm
index fcabddf..d06a5a3 100644
--- a/functional-tests/thin-functional-tests.scm
+++ b/functional-tests/thin-functional-tests.scm
@@ -14,7 +14,8 @@
(temp-file)
(thin metadata)
(thin xml)
- (srfi s8 receive))
+ (srfi s8 receive)
+ (xml))
(define-tool thin-check)
(define-tool thin-delta)
@@ -96,6 +97,32 @@
;; to run.
(define (register-thin-tests) #t)
+ ;; XML of metadata with empty thins
+ (define xml-with-empty-thins
+ (fmt #f
+ (tag 'superblock `((uuid . "")
+ (time . 0)
+ (transaction . 1)
+ (flags . 0)
+ (version . 2)
+ (data-block-size . 128)
+ (nr-data-blocks . 1024))
+ (tag 'device `((dev-id . 1)
+ (mapped-blocks . 16)
+ (transaction . 0)
+ (creation-time . 0)
+ (snap-time . 0))
+ (tag 'range-mapping `((origin-begin . 0)
+ (data-begin . 0)
+ (length . 16)
+ (time . 0))))
+ (tag 'device `((dev-id . 2)
+ (mapped-blocks . 0)
+ (transaction . 0)
+ (creation-time . 0)
+ (snap-time . 0))
+ " "))))
+
;;;-----------------------------------------------------------
;;; thin_check scenarios
;;;-----------------------------------------------------------
@@ -376,6 +403,17 @@
(run-fail-rcv (_ stderr) (thin-dump "--repair" "--transaction-id=5" "--data-block-size=128" md)
(assert-matches ".*nr data blocks.*" stderr))))
+ (define-scenario (thin-dump repair-superblock with-empty-devices)
+ "metadata with empty devices could be recovered"
+ (with-temp-file-sized ((md "thin.bin" (meg 4)))
+ (with-temp-file-containing ((xml "thin.xml" xml-with-empty-thins))
+ (run-ok (thin-restore "-i" xml "-o" md)))
+ (run-ok-rcv (expected-xml _) (thin-dump md)
+ (damage-superblock md)
+ (run-ok-rcv (repaired-xml stderr) (thin-dump "--repair" "--transaction-id=1" "--data-block-size=128" "--nr-data-blocks=1024" md)
+ (assert-eof stderr)
+ (assert-equal expected-xml repaired-xml)))))
+
;;;-----------------------------------------------------------
;;; thin_rmap scenarios
;;;-----------------------------------------------------------
@@ -572,6 +610,19 @@
(run-fail-rcv (_ stderr) (thin-repair "--transaction-id=5" "--data-block-size=128" "-i" md1 "-o" md2)
(assert-matches ".*nr data blocks.*" stderr)))))
+ (define-scenario (thin-repair superblock with-empty-devices)
+ "metadata with empty devices could be recovered"
+ (with-temp-file-sized ((md1 "thin.bin" (meg 4)))
+ (with-temp-file-containing ((xml "thin.xml" xml-with-empty-thins))
+ (run-ok (thin-restore "-i" xml "-o" md1)))
+ (run-ok-rcv (expected-xml _) (thin-dump md1)
+ (damage-superblock md1)
+ (with-empty-metadata (md2)
+ (run-ok-rcv (_ stderr) (thin-repair "--transaction-id=1" "--data-block-size=128" "--nr-data-blocks=1024" "-i" md1 "-o" md2)
+ (assert-eof stderr))
+ (run-ok-rcv (repaired-xml stderr) (thin-dump md2)
+ (assert-eof stderr)
+ (assert-equal expected-xml repaired-xml))))))
;;;-----------------------------------------------------------
;;; thin_metadata_pack scenarios
diff --git a/thin-provisioning/metadata_dumper.cc b/thin-provisioning/metadata_dumper.cc
index 37c6969..d169c27 100644
--- a/thin-provisioning/metadata_dumper.cc
+++ b/thin-provisioning/metadata_dumper.cc
@@ -438,6 +438,14 @@ namespace {
// in the bottom 24 bits. This means every block/time apart from block 0
// will result in a value that's outside the range of the metadata device.
bool is_top_level(node_ref<uint64_traits> &n) {
+ // A leaf node of value-size 8 and without mappings should be
+ // treated as a bottom-level leaf, so that it could be referenced
+ // by top-level nodes, if any. On the other hand, an empty
+ // top-level leaf doesn't help repairing.
+ if (!n.get_nr_entries()) {
+ return false;
+ }
+
auto nr_metadata_blocks = bm_.get_nr_blocks();
for (unsigned i = 0; i < n.get_nr_entries(); i++)
--
1.8.3.1