[Qemu-devel] [PATCH V7 5/6] blkdebug: add debug events for snapshot

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

Some code in qcow2-snapshot.c directly accesses bs->file, so in those
places errors can't be injected by other events. Since the code in
qcow2-snapshot.c is similar to the other qcow2 internal code (in regards
to e.g. the L1 table), add some debug events.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
---
 block/blkdebug.c       |    4 ++++
 block/qcow2-snapshot.c |    3 +++
 include/block/block.h  |    4 ++++
 3 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/block/blkdebug.c b/block/blkdebug.c
index 37cf028..891b549 100644
--- a/block/blkdebug.c
+++ b/block/blkdebug.c
@@ -186,6 +186,10 @@ static const char *event_names[BLKDBG_EVENT_MAX] = {
 
     [BLKDBG_FLUSH_TO_OS]                    = "flush_to_os",
     [BLKDBG_FLUSH_TO_DISK]                  = "flush_to_disk",
+
+    [BLKDBG_SNAPSHOT_L1_UPDATE]             = "snapshot_l1_update",
+    [BLKDBG_SNAPSHOT_LIST_UPDATE]           = "snapshot_list_update",
+    [BLKDBG_SNAPSHOT_HEADER_UPDATE]         = "snapshot_header_update",
 };
 
 static int get_event_by_name(const char *name, BlkDebugEvent *event)
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 5f787bc..2548de7 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -207,6 +207,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
     }
 
 
+    BLKDBG_EVENT(bs->file, BLKDBG_SNAPSHOT_LIST_UPDATE);
     /* Write all snapshots to the new list */
     for(i = 0; i < s->nb_snapshots; i++) {
         sn = s->snapshots + i;
@@ -292,6 +293,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs, Error **errp)
     header_data.nb_snapshots        = cpu_to_be32(s->nb_snapshots);
     header_data.snapshots_offset    = cpu_to_be64(snapshots_offset);
 
+    BLKDBG_EVENT(bs->file, BLKDBG_SNAPSHOT_HEADER_UPDATE);
     ret = bdrv_pwrite_sync(bs->file, offsetof(QCowHeader, nb_snapshots),
                            &header_data, sizeof(header_data));
     if (ret < 0) {
@@ -452,6 +454,7 @@ void qcow2_snapshot_create(BlockDriverState *bs,
         goto dealloc_cluster;
     }
 
+    BLKDBG_EVENT(bs->file, BLKDBG_SNAPSHOT_L1_UPDATE);
     ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table,
                       s->l1_size * sizeof(uint64_t));
     if (ret < 0) {
diff --git a/include/block/block.h b/include/block/block.h
index 36efaea..8901683 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -515,6 +515,10 @@ typedef enum {
     BLKDBG_FLUSH_TO_OS,
     BLKDBG_FLUSH_TO_DISK,
 
+    BLKDBG_SNAPSHOT_L1_UPDATE,
+    BLKDBG_SNAPSHOT_LIST_UPDATE,
+    BLKDBG_SNAPSHOT_HEADER_UPDATE,
+
     BLKDBG_EVENT_MAX,
 } BlkDebugEvent;
 
-- 
1.7.1