[libvirt] [PATCH v2 2/4] qemu: block: use the delete flag to delete snapshot images if requested

[Pavel Mores]

When blockcommit finishes successfully, one of the
qemuBlockJobProcessEventCompletedCommit() and
qemuBlockJobProcessEventCompletedActiveCommit() event handlers is called.
This is where the delete flag (stored in qemuBlockJobCommitData since the
previous commit) can actually be used to delete the committed snapshot
images if requested.

Signed-off-by: Pavel Mores <pmores at redhat.com>
---
 src/qemu/qemu_blockjob.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/src/qemu/qemu_blockjob.c b/src/qemu/qemu_blockjob.c
index 7d94a6ce38..cf221a2839 100644
--- a/src/qemu/qemu_blockjob.c
+++ b/src/qemu/qemu_blockjob.c
@@ -965,6 +965,31 @@ qemuBlockJobProcessEventCompletedPull(virQEMUDriverPtr driver,
 }
 
 
+/**
+ * Helper for qemuBlockJobProcessEventCompletedCommit() and
+ * qemuBlockJobProcessEventCompletedActiveCommit().  Relies on adjustments
+ * these functions perform on the 'backingStore' chain to function correctly.
+ *
+ * TODO look into removing backing store for non-local snapshots too
+ */
+static void
+qemuBlockJobUnlinkCommittedStorage(virStorageSourcePtr top)
+{
+    virStorageSourcePtr p = top;
+    const size_t errmsg_len = 128;
+    char errmsg_buf[errmsg_len];
+    char *errmsg;
+
+    for (; p != NULL; p = p->backingStore) {
+        if (virStorageSourceIsLocalStorage(p))
+            if (unlink(p->path) < 0) {
+                errmsg = strerror_r(errno, errmsg_buf, errmsg_len);
+                VIR_WARN("Unable to remove snapshot image file %s (%s)",
+                         p->path, errmsg);
+            }
+    }
+}
+
 /**
  * qemuBlockJobProcessEventCompletedCommit:
  * @driver: qemu driver object
@@ -1031,6 +1056,9 @@ qemuBlockJobProcessEventCompletedCommit(virQEMUDriverPtr driver,
     job->data.commit.topparent->backingStore = job->data.commit.base;
 
     qemuBlockJobEventProcessConcludedRemoveChain(driver, vm, asyncJob, job->data.commit.top);
+
+    if (job->data.commit.deleteCommittedImages)
+        qemuBlockJobUnlinkCommittedStorage(job->data.commit.top);
     virObjectUnref(job->data.commit.top);
     job->data.commit.top = NULL;
 
@@ -1121,6 +1149,9 @@ qemuBlockJobProcessEventCompletedActiveCommit(virQEMUDriverPtr driver,
     job->disk->src->readonly = job->data.commit.top->readonly;
 
     qemuBlockJobEventProcessConcludedRemoveChain(driver, vm, asyncJob, job->data.commit.top);
+
+    if (job->data.commit.deleteCommittedImages)
+        qemuBlockJobUnlinkCommittedStorage(job->data.commit.top);
     virObjectUnref(job->data.commit.top);
     job->data.commit.top = NULL;
     /* the mirror element does not serve functional purpose for the commit job */
-- 
2.21.0