os/bluestore: Add make_range_shared_maybe_merge

Adds function that converts a specified range in object to shared blobs,
possibly merging them with other shared blobs.

Modify make_range_shared_maybe_merge to allow for merging blobs.
It now uses can_merge_blobs and merge_blobs.

Add discard_unused_buffers() to make_range_shared.

Signed-off-by: Adam Kupczyk <akupczyk@ibm.com>

diff --git a/src/os/bluestore/BlueStore.cc b/src/os/bluestore/BlueStore.cc
index 310e15ed2312f2a24b0d183ebaa710d9b3ce2a36..235e5f5264194118d5679817ebd8773a0a1123bb 100644 (file)
--- a/src/os/bluestore/BlueStore.cc
+++ b/src/os/bluestore/BlueStore.cc
@@ -3124,6 +3124,78 @@ void BlueStore::ExtentMap::reblob_extents(uint32_t blob_start, uint32_t blob_end
   }
 }
 
+// Convert blobs in selected range to shared blobs.
+void BlueStore::ExtentMap::make_range_shared_maybe_merge(
+  BlueStore* store, TransContext* txc, CollectionRef& c,
+  OnodeRef& oldo, uint64_t srcoff, uint64_t length)
+{
+  uint64_t end = srcoff + length;
+  uint32_t dirty_range_begin = OBJECT_MAX_SIZE;
+  uint32_t dirty_range_end = 0;
+  // load entire object; in most cases we clone entire object anyway
+  oldo->extent_map.fault_range(c->store->db, 0, OBJECT_MAX_SIZE);
+  std::multimap<uint64_t /*blob_start*/, Blob*> candidates;
+  scan_shared_blobs(c, srcoff, length, candidates);
+
+  for (auto ep = oldo->extent_map.seek_lextent(srcoff);
+    ep != oldo->extent_map.extent_map.end(); ) {
+    auto& e = *ep;
+    if (e.logical_offset >= end) {
+      break;
+    }
+    dout(25) << __func__ << " src " << e
+            << " bc=" << e.blob->bc << dendl;
+    const bluestore_blob_t& blob = e.blob->get_blob();
+    // make sure it is shared
+    if (!blob.is_shared()) {
+      dirty_range_begin = std::min<uint32_t>(dirty_range_begin, e.blob_start());
+      // first try to find a shared blob nearby
+      // that can accomodate extra extents
+      uint32_t blob_width; //to signal when extents end
+      dout(20) << __func__ << std::hex
+              << " e.blob_start=" << e.blob_start()
+              << " e.logical_offset=" << e.logical_offset
+              << std::dec << dendl;
+      Blob* b = blob.is_compressed() ? nullptr :
+       find_mergable_companion(e.blob.get(), e.blob_start(), blob_width, candidates);
+      if (b) {
+       dout(20) << __func__ << " merging to: " << *b << " bc=" << b->bc << dendl;
+       e.blob->discard_unused_buffers(store->cct, oldo->c->cache);
+       b->discard_unused_buffers(store->cct, oldo->c->cache);
+       uint32_t b_logical_length = b->merge_blob(store->cct, e.blob.get());
+       for (auto p : blob.get_extents()) {
+         if (p.is_valid()) {
+           b->shared_blob->get_ref(p.offset, p.length);
+         }
+       }
+       // reblob extents might erase e
+       dirty_range_end = std::max<uint32_t>(dirty_range_end, e.blob_start() + b_logical_length);
+       uint32_t goto_logical_offset = e.logical_offset + e.length;
+       reblob_extents(e.blob_start(), e.blob_start() + blob_width,
+                      e.blob, b);
+       ep = oldo->extent_map.seek_lextent(goto_logical_offset);
+       dout(20) << __func__ << " merged: " << *b << dendl;
+      } else {
+       // no candidate, has to convert to shared
+       c->make_blob_shared(store->_assign_blobid(txc), e.blob);
+       ceph_assert(e.logical_end() > 0);
+       dirty_range_end = std::max<uint32_t>(dirty_range_end, e.logical_end());
+       ++ep;
+      }
+    } else {
+      c->load_shared_blob(e.blob->shared_blob);
+      ++ep;
+    }
+  }
+  if (dirty_range_begin < dirty_range_end) {
+    // source onode got modified in the process
+    oldo->extent_map.dirty_range(dirty_range_begin,
+                                dirty_range_end - dirty_range_begin);
+    oldo->extent_map.maybe_reshard(dirty_range_begin, dirty_range_end);
+    txc->write_onode(oldo);
+  }
+}
+
 void BlueStore::ExtentMap::dup(BlueStore* b, TransContext* txc,
   CollectionRef& c, OnodeRef& oldo, OnodeRef& newo, uint64_t& srcoff,
   uint64_t& length, uint64_t& dstoff) {

diff --git a/src/os/bluestore/BlueStore.h b/src/os/bluestore/BlueStore.h
index e45f55bbd14e0d8ff9126b86e5180308ce797c88..bd9a1561de84920b3152dc6e341912ab51a278b2 100644 (file)
--- a/src/os/bluestore/BlueStore.h
+++ b/src/os/bluestore/BlueStore.h
@@ -915,6 +915,8 @@ public:
                                  std::multimap<uint64_t /*blob_start*/, Blob*>& candidates);
     void reblob_extents(uint32_t blob_start, uint32_t blob_end,
                        BlobRef from_blob, BlobRef to_blob);
+    void make_range_shared_maybe_merge(BlueStore* store, TransContext* txc, CollectionRef& c,
+                                      OnodeRef& oldo, uint64_t srcoff, uint64_t length);
 
     void dup(BlueStore* b, TransContext*, CollectionRef&, OnodeRef&, OnodeRef&,
       uint64_t&, uint64_t&, uint64_t&);