rbd: implement 'export-diff' and 'import-diff' commands

Export a diff of an image from a previous snapshot to a file (or stdout).

Import a diff and apply it to an image, and then create the ending
snapshot.

Signed-off-by: Sage Weil <sage@inktank.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/qa/workunits/rbd/diff.sh b/qa/workunits/rbd/diff.sh
new file mode 100755
index 00000000000..6f9cd27ae42
--- /dev/null
+++ b/qa/workunits/rbd/diff.sh
@@ -0,0 +1,43 @@
+#!/bin/bash -ex
+
+function cleanup() {
+    rbd snap purge foo || :
+    rbd rm foo || :
+    rbd snap purge foo.copy || :
+    rbd rm foo.copy || :
+    rm -f foo.diff foo.out
+}
+
+cleanup
+
+rbd create foo --size 1000
+rbd bench-write foo --io-size 4096 --io-threads 5 --io-total 4096000 --io-pattern rand
+
+#rbd cp foo foo.copy
+rbd create foo.copy --size 1000
+rbd export-diff foo - | rbd import-diff - foo.copy
+
+rbd snap create foo --snap=two
+rbd bench-write foo --io-size 4096 --io-threads 5 --io-total 4096000 --io-pattern rand
+rbd snap create foo --snap=three
+rbd snap create foo.copy --snap=two
+
+rbd export-diff foo@three --from-snap two foo.diff
+rbd import-diff foo.diff foo.copy
+rbd snap ls foo.copy | grep three
+
+rbd export foo foo.out
+orig=`md5sum foo.out | awk '{print $1}'`
+rm foo.out
+rbd export foo.copy foo.out
+copy=`md5sum foo.out | awk '{print $1}'`
+
+if [ "$orig" != "$copy" ]; then
+    echo does not match
+    exit 1
+fi
+
+cleanup
+
+echo OK
+