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authorDenis V. Lunev <den@openvz.org>2015-11-19 09:42:01 +0300
committerJuan Quintela <quintela@redhat.com>2015-11-19 11:50:00 +0100
commite9ff957ac26e0e11869a3568cfa7423ae33c51e7 (patch)
tree202f78903d148296e9bd8a86814b47e10426816e /block
parent5df5416e639cd75bd85d243af41387c2418fa580 (diff)
snapshot: create helper to test that block drivers supports snapshots
The patch enforces proper locking for this operation. Signed-off-by: Denis V. Lunev <den@openvz.org> Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> CC: Kevin Wolf <kwolf@redhat.com> Tested-by: Greg Kurz <gkurz@linux.vnet.ibm.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/snapshot.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/block/snapshot.c b/block/snapshot.c
index 89500f2f18..d929d08913 100644
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -356,3 +356,27 @@ int bdrv_snapshot_load_tmp_by_id_or_name(BlockDriverState *bs,
return ret;
}
+
+
+/* Group operations. All block drivers are involved.
+ * These functions will properly handle dataplane (take aio_context_acquire
+ * when appropriate for appropriate block drivers) */
+
+bool bdrv_all_can_snapshot(BlockDriverState **first_bad_bs)
+{
+ bool ok = true;
+ BlockDriverState *bs = NULL;
+
+ while (ok && (bs = bdrv_next(bs))) {
+ AioContext *ctx = bdrv_get_aio_context(bs);
+
+ aio_context_acquire(ctx);
+ if (bdrv_is_inserted(bs) && !bdrv_is_read_only(bs)) {
+ ok = bdrv_can_snapshot(bs);
+ }
+ aio_context_release(ctx);
+ }
+
+ *first_bad_bs = bs;
+ return ok;
+}