diff options
Diffstat (limited to 'src/librbd/api/DiffIterate.cc')
| -rw-r--r-- | src/librbd/api/DiffIterate.cc | 376 |
1 files changed, 376 insertions, 0 deletions
diff --git a/src/librbd/api/DiffIterate.cc b/src/librbd/api/DiffIterate.cc new file mode 100644 index 000000000..042f5eafb --- /dev/null +++ b/src/librbd/api/DiffIterate.cc @@ -0,0 +1,376 @@ +// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- +// vim: ts=8 sw=2 smarttab + +#include "librbd/api/DiffIterate.h" +#include "librbd/ImageCtx.h" +#include "librbd/ImageState.h" +#include "librbd/ObjectMap.h" +#include "librbd/Utils.h" +#include "librbd/internal.h" +#include "librbd/io/AioCompletion.h" +#include "librbd/io/ImageDispatchSpec.h" +#include "librbd/object_map/DiffRequest.h" +#include "include/rados/librados.hpp" +#include "include/interval_set.h" +#include "common/errno.h" +#include "common/Cond.h" +#include "common/Throttle.h" +#include "osdc/Striper.h" +#include <boost/tuple/tuple.hpp> +#include <list> +#include <map> +#include <vector> + +#define dout_subsys ceph_subsys_rbd +#undef dout_prefix +#define dout_prefix *_dout << "librbd::DiffIterate: " + +namespace librbd { +namespace api { + +namespace { + +struct DiffContext { + DiffIterate<>::Callback callback; + void *callback_arg; + bool whole_object; + bool include_parent; + uint64_t from_snap_id; + uint64_t end_snap_id; + OrderedThrottle throttle; + + template <typename I> + DiffContext(I &image_ctx, DiffIterate<>::Callback callback, + void *callback_arg, bool _whole_object, bool _include_parent, + uint64_t _from_snap_id, uint64_t _end_snap_id) + : callback(callback), callback_arg(callback_arg), + whole_object(_whole_object), include_parent(_include_parent), + from_snap_id(_from_snap_id), end_snap_id(_end_snap_id), + throttle(image_ctx.config.template get_val<uint64_t>("rbd_concurrent_management_ops"), true) { + } +}; + +template <typename I> +class C_DiffObject : public Context { +public: + C_DiffObject(I &image_ctx, DiffContext &diff_context, uint64_t image_offset, + uint64_t image_length) + : m_image_ctx(image_ctx), m_cct(image_ctx.cct), + m_diff_context(diff_context), m_image_offset(image_offset), + m_image_length(image_length) { + } + + void send() { + Context* ctx = m_diff_context.throttle.start_op(this); + auto aio_comp = io::AioCompletion::create_and_start( + ctx, util::get_image_ctx(&m_image_ctx), io::AIO_TYPE_GENERIC); + int list_snaps_flags = 0; + if (!m_diff_context.include_parent || m_diff_context.from_snap_id != 0) { + list_snaps_flags |= io::LIST_SNAPS_FLAG_DISABLE_LIST_FROM_PARENT; + } + if (m_diff_context.whole_object) { + list_snaps_flags |= io::LIST_SNAPS_FLAG_WHOLE_OBJECT; + } + auto req = io::ImageDispatchSpec::create_list_snaps( + m_image_ctx, io::IMAGE_DISPATCH_LAYER_INTERNAL_START, + aio_comp, {{m_image_offset, m_image_length}}, + {m_diff_context.from_snap_id, m_diff_context.end_snap_id}, + list_snaps_flags, &m_snapshot_delta, {}); + req->send(); + } + +protected: + typedef boost::tuple<uint64_t, size_t, bool> Diff; + typedef std::list<Diff> Diffs; + + void finish(int r) override { + CephContext *cct = m_cct; + + if (r < 0) { + ldout(cct, 20) << "list_snaps failed: " << m_image_offset << "~" + << m_image_length << ": " << cpp_strerror(r) << dendl; + } + + Diffs diffs; + ldout(cct, 20) << "image extent " << m_image_offset << "~" + << m_image_length << ": list_snaps complete" << dendl; + + compute_diffs(&diffs); + for (Diffs::const_iterator d = diffs.begin(); d != diffs.end(); ++d) { + r = m_diff_context.callback(d->get<0>(), d->get<1>(), d->get<2>(), + m_diff_context.callback_arg); + if (r < 0) { + break; + } + } + m_diff_context.throttle.end_op(r); + } + +private: + I& m_image_ctx; + CephContext *m_cct; + DiffContext &m_diff_context; + uint64_t m_image_offset; + uint64_t m_image_length; + + io::SnapshotDelta m_snapshot_delta; + + void compute_diffs(Diffs *diffs) { + CephContext *cct = m_cct; + + // merge per-snapshot deltas into an aggregate + io::SparseExtents aggregate_snapshot_extents; + for (auto& [key, snapshot_extents] : m_snapshot_delta) { + for (auto& snapshot_extent : snapshot_extents) { + auto state = snapshot_extent.get_val().state; + + // ignore DNE object (and parent) + if ((state == io::SPARSE_EXTENT_STATE_DNE) || + (key == io::INITIAL_WRITE_READ_SNAP_IDS && + state == io::SPARSE_EXTENT_STATE_ZEROED)) { + continue; + } + + aggregate_snapshot_extents.insert( + snapshot_extent.get_off(), snapshot_extent.get_len(), + {state, snapshot_extent.get_len()}); + } + } + + // build delta callback set + for (auto& snapshot_extent : aggregate_snapshot_extents) { + ldout(cct, 20) << "off=" << snapshot_extent.get_off() << ", " + << "len=" << snapshot_extent.get_len() << ", " + << "state=" << snapshot_extent.get_val().state << dendl; + diffs->emplace_back( + snapshot_extent.get_off(), snapshot_extent.get_len(), + snapshot_extent.get_val().state == io::SPARSE_EXTENT_STATE_DATA); + } + } +}; + +int simple_diff_cb(uint64_t off, size_t len, int exists, void *arg) { + // it's possible for a discard to create a hole in the parent image -- ignore + if (exists) { + interval_set<uint64_t> *diff = static_cast<interval_set<uint64_t> *>(arg); + diff->insert(off, len); + } + return 0; +} + +} // anonymous namespace + +template <typename I> +int DiffIterate<I>::diff_iterate(I *ictx, + const cls::rbd::SnapshotNamespace& from_snap_namespace, + const char *fromsnapname, + uint64_t off, uint64_t len, + bool include_parent, bool whole_object, + int (*cb)(uint64_t, size_t, int, void *), + void *arg) +{ + ldout(ictx->cct, 20) << "diff_iterate " << ictx << " off = " << off + << " len = " << len << dendl; + + if (!ictx->data_ctx.is_valid()) { + return -ENODEV; + } + + // ensure previous writes are visible to listsnaps + C_SaferCond flush_ctx; + { + std::shared_lock owner_locker{ictx->owner_lock}; + auto aio_comp = io::AioCompletion::create_and_start(&flush_ctx, ictx, + io::AIO_TYPE_FLUSH); + auto req = io::ImageDispatchSpec::create_flush( + *ictx, io::IMAGE_DISPATCH_LAYER_INTERNAL_START, + aio_comp, io::FLUSH_SOURCE_INTERNAL, {}); + req->send(); + } + int r = flush_ctx.wait(); + if (r < 0) { + return r; + } + + r = ictx->state->refresh_if_required(); + if (r < 0) { + return r; + } + + ictx->image_lock.lock_shared(); + r = clip_io(ictx, off, &len); + ictx->image_lock.unlock_shared(); + if (r < 0) { + return r; + } + + DiffIterate command(*ictx, from_snap_namespace, fromsnapname, off, len, + include_parent, whole_object, cb, arg); + r = command.execute(); + return r; +} + +template <typename I> +int DiffIterate<I>::execute() { + CephContext* cct = m_image_ctx.cct; + + ceph_assert(m_image_ctx.data_ctx.is_valid()); + + librados::snap_t from_snap_id = 0; + librados::snap_t end_snap_id; + uint64_t from_size = 0; + uint64_t end_size; + { + std::shared_lock image_locker{m_image_ctx.image_lock}; + if (m_from_snap_name) { + from_snap_id = m_image_ctx.get_snap_id(m_from_snap_namespace, + m_from_snap_name); + from_size = m_image_ctx.get_image_size(from_snap_id); + } + end_snap_id = m_image_ctx.snap_id; + end_size = m_image_ctx.get_image_size(end_snap_id); + } + + if (from_snap_id == CEPH_NOSNAP) { + return -ENOENT; + } + if (from_snap_id == end_snap_id) { + // no diff. + return 0; + } + if (from_snap_id >= end_snap_id) { + return -EINVAL; + } + + int r; + bool fast_diff_enabled = false; + BitVector<2> object_diff_state; + interval_set<uint64_t> parent_diff; + if (m_whole_object) { + C_SaferCond ctx; + auto req = object_map::DiffRequest<I>::create(&m_image_ctx, from_snap_id, + end_snap_id, + &object_diff_state, &ctx); + req->send(); + + r = ctx.wait(); + if (r < 0) { + ldout(cct, 5) << "fast diff disabled" << dendl; + } else { + ldout(cct, 5) << "fast diff enabled" << dendl; + fast_diff_enabled = true; + + // check parent overlap only if we are comparing to the beginning of time + if (m_include_parent && from_snap_id == 0) { + std::shared_lock image_locker{m_image_ctx.image_lock}; + uint64_t overlap = 0; + m_image_ctx.get_parent_overlap(m_image_ctx.snap_id, &overlap); + if (m_image_ctx.parent && overlap > 0) { + ldout(cct, 10) << " first getting parent diff" << dendl; + DiffIterate diff_parent(*m_image_ctx.parent, {}, nullptr, 0, overlap, + true, true, &simple_diff_cb, &parent_diff); + r = diff_parent.execute(); + if (r < 0) { + return r; + } + } + } + } + } + + ldout(cct, 5) << "diff_iterate from " << from_snap_id << " to " + << end_snap_id << " size from " << from_size + << " to " << end_size << dendl; + DiffContext diff_context(m_image_ctx, m_callback, m_callback_arg, + m_whole_object, m_include_parent, from_snap_id, + end_snap_id); + + uint64_t period = m_image_ctx.get_stripe_period(); + uint64_t off = m_offset; + uint64_t left = m_length; + + while (left > 0) { + uint64_t period_off = off - (off % period); + uint64_t read_len = min(period_off + period - off, left); + + if (fast_diff_enabled) { + // map to extents + map<object_t,vector<ObjectExtent> > object_extents; + Striper::file_to_extents(cct, m_image_ctx.format_string, + &m_image_ctx.layout, off, read_len, 0, + object_extents, 0); + + // get diff info for each object and merge adjacent stripe units + // into an aggregate (this also sorts them) + io::SparseExtents aggregate_sparse_extents; + for (auto& [object, extents] : object_extents) { + const uint64_t object_no = extents.front().objectno; + uint8_t diff_state = object_diff_state[object_no]; + ldout(cct, 20) << "object " << object << ": diff_state=" + << (int)diff_state << dendl; + + if (diff_state == object_map::DIFF_STATE_HOLE && + from_snap_id == 0 && !parent_diff.empty()) { + // no data in child object -- report parent diff instead + for (auto& oe : extents) { + for (auto& be : oe.buffer_extents) { + interval_set<uint64_t> o; + o.insert(off + be.first, be.second); + o.intersection_of(parent_diff); + ldout(cct, 20) << " reporting parent overlap " << o << dendl; + for (auto e = o.begin(); e != o.end(); ++e) { + aggregate_sparse_extents.insert(e.get_start(), e.get_len(), + {io::SPARSE_EXTENT_STATE_DATA, + e.get_len()}); + } + } + } + } else if (diff_state == object_map::DIFF_STATE_HOLE_UPDATED || + diff_state == object_map::DIFF_STATE_DATA_UPDATED) { + auto state = (diff_state == object_map::DIFF_STATE_HOLE_UPDATED ? + io::SPARSE_EXTENT_STATE_ZEROED : io::SPARSE_EXTENT_STATE_DATA); + for (auto& oe : extents) { + for (auto& be : oe.buffer_extents) { + aggregate_sparse_extents.insert(off + be.first, be.second, + {state, be.second}); + } + } + } + } + + for (const auto& se : aggregate_sparse_extents) { + ldout(cct, 20) << "off=" << se.get_off() << ", len=" << se.get_len() + << ", state=" << se.get_val().state << dendl; + r = m_callback(se.get_off(), se.get_len(), + se.get_val().state == io::SPARSE_EXTENT_STATE_DATA, + m_callback_arg); + if (r < 0) { + return r; + } + } + } else { + auto diff_object = new C_DiffObject<I>(m_image_ctx, diff_context, off, + read_len); + diff_object->send(); + + if (diff_context.throttle.pending_error()) { + r = diff_context.throttle.wait_for_ret(); + return r; + } + } + + left -= read_len; + off += read_len; + } + + r = diff_context.throttle.wait_for_ret(); + if (r < 0) { + return r; + } + return 0; +} + +} // namespace api +} // namespace librbd + +template class librbd::api::DiffIterate<librbd::ImageCtx>; |