initial code repo

[stor4nfv.git] / src / ceph / src / librbd / io / ReadResult.cc

diff --git a/src/ceph/src/librbd/io/ReadResult.cc b/src/ceph/src/librbd/io/ReadResult.cc
new file mode 100644 (file)
index 0000000..1b8cdb0
--- /dev/null
+++ b/src/ceph/src/librbd/io/ReadResult.cc
@@ -0,0 +1,166 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include "librbd/io/ReadResult.h"
+#include "include/buffer.h"
+#include "common/dout.h"
+#include "librbd/io/AioCompletion.h"
+#include <boost/variant/apply_visitor.hpp>
+#include <boost/variant/static_visitor.hpp>
+
+#define dout_subsys ceph_subsys_rbd
+#undef dout_prefix
+#define dout_prefix *_dout << "librbd::io::ReadResult: " << this \
+                           << " " << __func__ << ": "
+
+namespace librbd {
+namespace io {
+
+struct ReadResult::SetClipLengthVisitor : public boost::static_visitor<void> {
+  size_t length;
+
+  SetClipLengthVisitor(size_t length) : length(length) {
+  }
+
+  void operator()(Linear &linear) const {
+    assert(length <= linear.buf_len);
+    linear.buf_len = length;
+  }
+
+  template <typename T>
+  void operator()(T &t) const {
+  }
+};
+
+struct ReadResult::AssembleResultVisitor : public boost::static_visitor<void> {
+  CephContext *cct;
+  Striper::StripedReadResult &destriper;
+
+  AssembleResultVisitor(CephContext *cct, Striper::StripedReadResult &destriper)
+    : cct(cct), destriper(destriper) {
+  }
+
+  void operator()(Empty &empty) const {
+    ldout(cct, 20) << "dropping read result" << dendl;
+  }
+
+  void operator()(Linear &linear) const {
+    ldout(cct, 20) << "copying resulting bytes to "
+                   << reinterpret_cast<void*>(linear.buf) << dendl;
+    destriper.assemble_result(cct, linear.buf, linear.buf_len);
+  }
+
+  void operator()(Vector &vector) const {
+    bufferlist bl;
+    destriper.assemble_result(cct, bl, true);
+
+    ldout(cct, 20) << "copying resulting " << bl.length() << " bytes to iovec "
+                   << reinterpret_cast<const void*>(vector.iov) << dendl;
+
+    bufferlist::iterator it = bl.begin();
+    size_t length = bl.length();
+    size_t offset = 0;
+    int idx = 0;
+    for (; offset < length && idx < vector.iov_count; idx++) {
+      size_t len = MIN(vector.iov[idx].iov_len, length - offset);
+      it.copy(len, static_cast<char *>(vector.iov[idx].iov_base));
+      offset += len;
+    }
+    assert(offset == bl.length());
+  }
+
+  void operator()(Bufferlist &bufferlist) const {
+    bufferlist.bl->clear();
+    destriper.assemble_result(cct, *bufferlist.bl, true);
+
+    ldout(cct, 20) << "moved resulting " << bufferlist.bl->length() << " "
+                   << "bytes to bl " << reinterpret_cast<void*>(bufferlist.bl)
+                   << dendl;
+  }
+};
+
+ReadResult::C_ReadRequest::C_ReadRequest(AioCompletion *aio_completion)
+  : aio_completion(aio_completion) {
+  aio_completion->add_request();
+}
+
+void ReadResult::C_ReadRequest::finish(int r) {
+  aio_completion->complete_request(r);
+}
+
+void ReadResult::C_ImageReadRequest::finish(int r) {
+  CephContext *cct = aio_completion->ictx->cct;
+  ldout(cct, 10) << "C_ImageReadRequest: r=" << r
+                 << dendl;
+  if (r >= 0) {
+    size_t length = 0;
+    for (auto &image_extent : image_extents) {
+      length += image_extent.second;
+    }
+    assert(length == bl.length());
+
+    aio_completion->lock.Lock();
+    aio_completion->read_result.m_destriper.add_partial_result(
+      cct, bl, image_extents);
+    aio_completion->lock.Unlock();
+    r = length;
+  }
+
+  C_ReadRequest::finish(r);
+}
+
+void ReadResult::C_SparseReadRequestBase::finish(ExtentMap &extent_map,
+                                                 const Extents &buffer_extents,
+                                                 uint64_t offset, size_t length,
+                                                 bufferlist &bl, int r) {
+  aio_completion->lock.Lock();
+  CephContext *cct = aio_completion->ictx->cct;
+  ldout(cct, 10) << "C_SparseReadRequestBase: r = " << r
+                 << dendl;
+
+  if (r >= 0 || r == -ENOENT) { // this was a sparse_read operation
+    ldout(cct, 10) << " got " << extent_map
+                   << " for " << buffer_extents
+                   << " bl " << bl.length() << dendl;
+    // reads from the parent don't populate the m_ext_map and the overlap
+    // may not be the full buffer.  compensate here by filling in m_ext_map
+    // with the read extent when it is empty.
+    if (extent_map.empty()) {
+      extent_map[offset] = bl.length();
+    }
+
+    aio_completion->read_result.m_destriper.add_partial_sparse_result(
+      cct, bl, extent_map, offset, buffer_extents);
+    r = length;
+  }
+  aio_completion->lock.Unlock();
+
+  C_ReadRequest::finish(r);
+}
+
+ReadResult::ReadResult() : m_buffer(Empty()) {
+}
+
+ReadResult::ReadResult(char *buf, size_t buf_len)
+  : m_buffer(Linear(buf, buf_len)) {
+}
+
+ReadResult::ReadResult(const struct iovec *iov, int iov_count)
+  : m_buffer(Vector(iov, iov_count)) {
+}
+
+ReadResult::ReadResult(ceph::bufferlist *bl)
+  : m_buffer(Bufferlist(bl)) {
+}
+
+void ReadResult::set_clip_length(size_t length) {
+  boost::apply_visitor(SetClipLengthVisitor(length), m_buffer);
+}
+
+void ReadResult::assemble_result(CephContext *cct) {
+  boost::apply_visitor(AssembleResultVisitor(cct, m_destriper), m_buffer);
+}
+
+} // namespace io
+} // namespace librbd
+