librbd/migration: move snapshot delta helpers to utils

The RawFormat class has logic for computing snapshot deltas that
can be re-used by the new QCOWFormat class.

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

diff --git a/src/librbd/migration/RawFormat.cc b/src/librbd/migration/RawFormat.cc
index 774762594f4b2fd4510da662979cdded499ffa06..0b655d36882001f7a152767c8a9cc5b154465956 100644 (file)
--- a/src/librbd/migration/RawFormat.cc
+++ b/src/librbd/migration/RawFormat.cc
@@ -11,6 +11,7 @@
 #include "librbd/io/ReadResult.h"
 #include "librbd/migration/SnapshotInterface.h"
 #include "librbd/migration/SourceSpecBuilder.h"
+#include "librbd/migration/Utils.h"
 
 namespace librbd {
 namespace migration {
@@ -205,26 +206,8 @@ void RawFormat<I>::list_snaps(io::Extents&& image_extents,
     // zero out any space between the previous snapshot end and this
     // snapshot's end
     auto& snap_info = snapshot->get_snap_info();
-    if (previous_size && *previous_size > snap_info.size) {
-      ldout(cct, 20) << "snapshot resize " << *previous_size << " -> "
-                     << snap_info.size << dendl;
-      interval_set<uint64_t> zero_interval;
-      zero_interval.insert(snap_info.size, *previous_size - snap_info.size);
-
-      for (auto& image_extent : image_extents) {
-        interval_set<uint64_t> image_interval;
-        image_interval.insert(image_extent.first, image_extent.second);
-
-        image_interval.intersection_of(zero_interval);
-        for (auto [image_offset, image_length] : image_interval) {
-          ldout(cct, 20) << "zeroing extent " << image_offset << "~"
-                         << image_length << " at snapshot " << snap_id << dendl;
-          sparse_extents.insert(image_offset, image_length,
-                                {io::SPARSE_EXTENT_STATE_ZEROED, image_length});
-        }
-      }
-    }
-    previous_size = snap_info.size;
+    util::zero_shrunk_snapshot(cct, image_extents, snap_id, snap_info.size,
+                               &previous_size, &sparse_extents);
 
     // build set of data/zeroed extents for the current snapshot
     snapshot->list_snap(io::Extents{image_extents}, list_snaps_flags,
@@ -242,45 +225,7 @@ void RawFormat<I>::handle_list_snaps(int r, io::SnapIds&& snap_ids,
   ldout(cct, 20) << "r=" << r << ", "
                  << "snapshot_delta=" << snapshot_delta << dendl;
 
-  io::SnapshotDelta orig_snapshot_delta = std::move(*snapshot_delta);
-  snapshot_delta->clear();
-
-  auto snap_id_it = snap_ids.begin();
-  ceph_assert(snap_id_it != snap_ids.end());
-
-  // merge any snapshot intervals that were not requested
-  std::list<io::SparseExtents*> pending_sparse_extents;
-  for (auto& [snap_key, sparse_extents] : orig_snapshot_delta) {
-    // advance to next valid requested snap id
-    while (snap_id_it != snap_ids.end() && *snap_id_it < snap_key.first) {
-      ++snap_id_it;
-    }
-    if (snap_id_it == snap_ids.end()) {
-      break;
-    }
-
-    // loop through older write/read snapshot sparse extents to remove any
-    // overlaps with the current sparse extent
-    for (auto prev_sparse_extents : pending_sparse_extents) {
-      for (auto& sparse_extent : sparse_extents) {
-        prev_sparse_extents->erase(sparse_extent.get_off(),
-                                   sparse_extent.get_len());
-      }
-    }
-
-    auto write_read_snap_ids = std::make_pair(*snap_id_it, snap_key.second);
-    (*snapshot_delta)[write_read_snap_ids] = std::move(sparse_extents);
-
-    if (write_read_snap_ids.first > snap_key.first) {
-      // the current snapshot wasn't requested so it might need to get
-      // merged with a later snapshot
-      pending_sparse_extents.push_back(&(*snapshot_delta)[write_read_snap_ids]);
-    } else {
-      // we don't merge results passed a valid requested snapshot
-      pending_sparse_extents.clear();
-    }
-  }
-
+  util::merge_snapshot_delta(snap_ids, snapshot_delta);
   on_finish->complete(r);
 }
 

diff --git a/src/librbd/migration/Utils.cc b/src/librbd/migration/Utils.cc
index 23b803d2762753e7cfc6c85fb89f7a4ceafff72e..c5c1279d899c3b29678d42bc24a95a39d3cabf2b 100644 (file)
--- a/src/librbd/migration/Utils.cc
+++ b/src/librbd/migration/Utils.cc
@@ -60,6 +60,74 @@ int parse_url(CephContext* cct, const std::string& url, UrlSpec* url_spec) {
   return 0;
 }
 
+void zero_shrunk_snapshot(CephContext* cct, const io::Extents& image_extents,
+                          uint64_t snap_id, uint64_t new_size,
+                          std::optional<uint64_t> *previous_size,
+                          io::SparseExtents* sparse_extents) {
+  if (*previous_size && **previous_size > new_size) {
+    ldout(cct, 20) << "snapshot resize " << **previous_size << " -> "
+                   << new_size << dendl;
+    interval_set<uint64_t> zero_interval;
+    zero_interval.insert(new_size, **previous_size - new_size);
+
+    for (auto& image_extent : image_extents) {
+      interval_set<uint64_t> image_interval;
+      image_interval.insert(image_extent.first, image_extent.second);
+
+      image_interval.intersection_of(zero_interval);
+      for (auto [image_offset, image_length] : image_interval) {
+        ldout(cct, 20) << "zeroing extent " << image_offset << "~"
+                       << image_length << " at snapshot " << snap_id << dendl;
+        sparse_extents->insert(image_offset, image_length,
+                               {io::SPARSE_EXTENT_STATE_ZEROED, image_length});
+      }
+    }
+  }
+  *previous_size = new_size;
+}
+
+void merge_snapshot_delta(const io::SnapIds& snap_ids,
+                          io::SnapshotDelta* snapshot_delta) {
+  io::SnapshotDelta orig_snapshot_delta = std::move(*snapshot_delta);
+  snapshot_delta->clear();
+
+  auto snap_id_it = snap_ids.begin();
+  ceph_assert(snap_id_it != snap_ids.end());
+
+  // merge any snapshot intervals that were not requested
+  std::list<io::SparseExtents*> pending_sparse_extents;
+  for (auto& [snap_key, sparse_extents] : orig_snapshot_delta) {
+    // advance to next valid requested snap id
+    while (snap_id_it != snap_ids.end() && *snap_id_it < snap_key.first) {
+      ++snap_id_it;
+    }
+    if (snap_id_it == snap_ids.end()) {
+      break;
+    }
+
+    // loop through older write/read snapshot sparse extents to remove any
+    // overlaps with the current sparse extent
+    for (auto prev_sparse_extents : pending_sparse_extents) {
+      for (auto& sparse_extent : sparse_extents) {
+        prev_sparse_extents->erase(sparse_extent.get_off(),
+                                   sparse_extent.get_len());
+      }
+    }
+
+    auto write_read_snap_ids = std::make_pair(*snap_id_it, snap_key.second);
+    (*snapshot_delta)[write_read_snap_ids] = std::move(sparse_extents);
+
+    if (write_read_snap_ids.first > snap_key.first) {
+      // the current snapshot wasn't requested so it might need to get
+      // merged with a later snapshot
+      pending_sparse_extents.push_back(&(*snapshot_delta)[write_read_snap_ids]);
+    } else {
+      // we don't merge results passed a valid requested snapshot
+      pending_sparse_extents.clear();
+    }
+  }
+}
+
 } // namespace util
 } // namespace migration
 } // namespace librbd

diff --git a/src/librbd/migration/Utils.h b/src/librbd/migration/Utils.h
index a3e2fe0132c63b986435d775140918482d2c74b2..afbadde7d178468567815f22d6ff35e4565a5da5 100644 (file)
--- a/src/librbd/migration/Utils.h
+++ b/src/librbd/migration/Utils.h
@@ -5,7 +5,9 @@
 #define CEPH_LIBRBD_MIGRATION_UTILS_H
 
 #include "include/common_fwd.h"
+#include "librbd/io/Types.h"
 #include "librbd/migration/Types.h"
+#include <optional>
 #include <string>
 
 namespace librbd {
@@ -14,6 +16,13 @@ namespace util {
 
 int parse_url(CephContext* cct, const std::string& url, UrlSpec* url_spec);
 
+void zero_shrunk_snapshot(CephContext* cct, const io::Extents& image_extents,
+                          uint64_t snap_id, uint64_t new_size,
+                          std::optional<uint64_t> *previous_size,
+                          io::SparseExtents* sparse_extents);
+void merge_snapshot_delta(const io::SnapIds& snap_ids,
+                          io::SnapshotDelta* snapshot_delta);
+
 } // namespace util
 } // namespace migration
 } // namespace librbd