From: Jason Dillaman <dillaman@redhat.com>
Date: Fri, 8 May 2015 19:15:29 +0000 (-0400)
Subject: librbd: add new copyup helper method
X-Git-Tag: v9.0.2~13^2~12
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=da5b565f9f1c83891c3523aba87120fa0915312d;p=ceph.git

librbd: add new copyup helper method

ImageCtx::get_copyup_snap_id returns the oldest snapshot
to be used when calculating parent image overlaps.

Signed-off-by: Jason Dillaman <dillaman@redhat.com>

Conflicts:
	src/librbd/AioRequest.cc
---

diff --git a/src/librbd/ImageCtx.cc b/src/librbd/ImageCtx.cc
index 298eeed12ffc..c5e253ebd0a3 100644
--- a/src/librbd/ImageCtx.cc
+++ b/src/librbd/ImageCtx.cc
@@ -586,6 +586,17 @@ public:
     return -ENOENT;
   }
 
+  uint64_t ImageCtx::get_copyup_snap_id() const
+  {
+    assert(snap_lock.is_locked());
+    // copyup requires the largest possible parent overlap,
+    // which is always the oldest snapshot (if any).
+    if (!snaps.empty()) {
+      return snaps.back();
+    }
+    return CEPH_NOSNAP;
+  }
+
   void ImageCtx::aio_read_from_cache(object_t o, uint64_t object_no,
 				     bufferlist *bl, size_t len,
 				     uint64_t off, Context *onfinish,
diff --git a/src/librbd/ImageCtx.h b/src/librbd/ImageCtx.h
index 11028705f593..e0b5cb477ab7 100644
--- a/src/librbd/ImageCtx.h
+++ b/src/librbd/ImageCtx.h
@@ -210,6 +210,7 @@ namespace librbd {
     uint64_t get_parent_snap_id(librados::snap_t in_snap_id) const;
     int get_parent_overlap(librados::snap_t in_snap_id,
 			   uint64_t *overlap) const;
+    uint64_t get_copyup_snap_id() const;
     void aio_read_from_cache(object_t o, uint64_t object_no, bufferlist *bl,
 			     size_t len, uint64_t off, Context *onfinish,
 			     int fadvise_flags);