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-rw-r--r--src/librbd/LibrbdWriteback.cc270
1 files changed, 270 insertions, 0 deletions
diff --git a/src/librbd/LibrbdWriteback.cc b/src/librbd/LibrbdWriteback.cc
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+++ b/src/librbd/LibrbdWriteback.cc
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+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#include <errno.h>
+
+#include "common/ceph_context.h"
+#include "common/dout.h"
+#include "common/Mutex.h"
+#include "common/WorkQueue.h"
+#include "osdc/Striper.h"
+#include "include/Context.h"
+#include "include/rados/librados.hpp"
+#include "include/rbd/librbd.hpp"
+
+#include "librbd/ExclusiveLock.h"
+#include "librbd/ImageCtx.h"
+#include "librbd/internal.h"
+#include "librbd/LibrbdWriteback.h"
+#include "librbd/ObjectMap.h"
+#include "librbd/Journal.h"
+#include "librbd/Utils.h"
+#include "librbd/io/AioCompletion.h"
+#include "librbd/io/ObjectDispatchSpec.h"
+#include "librbd/io/ObjectDispatcher.h"
+#include "librbd/io/ReadResult.h"
+
+#include "include/ceph_assert.h"
+
+#define dout_subsys ceph_subsys_rbd
+#undef dout_prefix
+#define dout_prefix *_dout << "librbdwriteback: "
+
+namespace librbd {
+
+ /**
+ * context to wrap another context in a Mutex
+ *
+ * @param cct cct
+ * @param c context to finish
+ * @param l mutex to lock
+ */
+ class C_ReadRequest : public Context {
+ public:
+ C_ReadRequest(CephContext *cct, Context *c, Mutex *cache_lock)
+ : m_cct(cct), m_ctx(c), m_cache_lock(cache_lock) {
+ }
+ void finish(int r) override {
+ ldout(m_cct, 20) << "aio_cb completing " << dendl;
+ {
+ Mutex::Locker cache_locker(*m_cache_lock);
+ m_ctx->complete(r);
+ }
+ ldout(m_cct, 20) << "aio_cb finished" << dendl;
+ }
+ private:
+ CephContext *m_cct;
+ Context *m_ctx;
+ Mutex *m_cache_lock;
+ };
+
+ class C_OrderedWrite : public Context {
+ public:
+ C_OrderedWrite(CephContext *cct, LibrbdWriteback::write_result_d *result,
+ const ZTracer::Trace &trace, LibrbdWriteback *wb)
+ : m_cct(cct), m_result(result), m_trace(trace), m_wb_handler(wb) {}
+ ~C_OrderedWrite() override {}
+ void finish(int r) override {
+ ldout(m_cct, 20) << "C_OrderedWrite completing " << m_result << dendl;
+ {
+ Mutex::Locker l(m_wb_handler->m_lock);
+ ceph_assert(!m_result->done);
+ m_result->done = true;
+ m_result->ret = r;
+ m_wb_handler->complete_writes(m_result->oid);
+ }
+ ldout(m_cct, 20) << "C_OrderedWrite finished " << m_result << dendl;
+ m_trace.event("finish");
+ }
+ private:
+ CephContext *m_cct;
+ LibrbdWriteback::write_result_d *m_result;
+ ZTracer::Trace m_trace;
+ LibrbdWriteback *m_wb_handler;
+ };
+
+ struct C_CommitIOEventExtent : public Context {
+ ImageCtx *image_ctx;
+ uint64_t journal_tid;
+ uint64_t offset;
+ uint64_t length;
+
+ C_CommitIOEventExtent(ImageCtx *image_ctx, uint64_t journal_tid,
+ uint64_t offset, uint64_t length)
+ : image_ctx(image_ctx), journal_tid(journal_tid), offset(offset),
+ length(length) {
+ }
+
+ void finish(int r) override {
+ // all IO operations are flushed prior to closing the journal
+ ceph_assert(image_ctx->journal != nullptr);
+
+ image_ctx->journal->commit_io_event_extent(journal_tid, offset, length,
+ r);
+ }
+ };
+
+ LibrbdWriteback::LibrbdWriteback(ImageCtx *ictx, Mutex& lock)
+ : m_tid(0), m_lock(lock), m_ictx(ictx) {
+ }
+
+ void LibrbdWriteback::read(const object_t& oid, uint64_t object_no,
+ const object_locator_t& oloc,
+ uint64_t off, uint64_t len, snapid_t snapid,
+ bufferlist *pbl, uint64_t trunc_size,
+ __u32 trunc_seq, int op_flags,
+ const ZTracer::Trace &parent_trace,
+ Context *onfinish)
+ {
+ ZTracer::Trace trace;
+ if (parent_trace.valid()) {
+ trace.init("", &m_ictx->trace_endpoint, &parent_trace);
+ trace.copy_name("cache read " + oid.name);
+ trace.event("start");
+ }
+
+ // on completion, take the mutex and then call onfinish.
+ onfinish = new C_ReadRequest(m_ictx->cct, onfinish, &m_lock);
+
+ // re-use standard object read state machine
+ auto aio_comp = io::AioCompletion::create_and_start(onfinish, m_ictx,
+ io::AIO_TYPE_READ);
+ aio_comp->read_result = io::ReadResult{pbl};
+ aio_comp->set_request_count(1);
+
+ auto req_comp = new io::ReadResult::C_ObjectReadRequest(
+ aio_comp, off, len, {{0, len}});
+
+ auto req = io::ObjectDispatchSpec::create_read(
+ m_ictx, io::OBJECT_DISPATCH_LAYER_CACHE, oid.name, object_no, off, len,
+ snapid, op_flags, trace, &req_comp->bl, &req_comp->extent_map, req_comp);
+ req->send();
+ }
+
+ bool LibrbdWriteback::may_copy_on_write(const object_t& oid, uint64_t read_off, uint64_t read_len, snapid_t snapid)
+ {
+ m_ictx->snap_lock.get_read();
+ librados::snap_t snap_id = m_ictx->snap_id;
+ m_ictx->parent_lock.get_read();
+ uint64_t overlap = 0;
+ m_ictx->get_parent_overlap(snap_id, &overlap);
+ m_ictx->parent_lock.put_read();
+ m_ictx->snap_lock.put_read();
+
+ uint64_t object_no = oid_to_object_no(oid.name, m_ictx->object_prefix);
+
+ // reverse map this object extent onto the parent
+ vector<pair<uint64_t,uint64_t> > objectx;
+ Striper::extent_to_file(m_ictx->cct, &m_ictx->layout,
+ object_no, 0, m_ictx->layout.object_size,
+ objectx);
+ uint64_t object_overlap = m_ictx->prune_parent_extents(objectx, overlap);
+ bool may = object_overlap > 0;
+ ldout(m_ictx->cct, 10) << "may_copy_on_write " << oid << " " << read_off
+ << "~" << read_len << " = " << may << dendl;
+ return may;
+ }
+
+ ceph_tid_t LibrbdWriteback::write(const object_t& oid,
+ const object_locator_t& oloc,
+ uint64_t off, uint64_t len,
+ const SnapContext& snapc,
+ const bufferlist &bl,
+ ceph::real_time mtime, uint64_t trunc_size,
+ __u32 trunc_seq, ceph_tid_t journal_tid,
+ const ZTracer::Trace &parent_trace,
+ Context *oncommit)
+ {
+ ZTracer::Trace trace;
+ if (parent_trace.valid()) {
+ trace.init("", &m_ictx->trace_endpoint, &parent_trace);
+ trace.copy_name("writeback " + oid.name);
+ trace.event("start");
+ }
+
+ uint64_t object_no = oid_to_object_no(oid.name, m_ictx->object_prefix);
+
+ write_result_d *result = new write_result_d(oid.name, oncommit);
+ m_writes[oid.name].push(result);
+ ldout(m_ictx->cct, 20) << "write will wait for result " << result << dendl;
+
+ bufferlist bl_copy(bl);
+
+ Context *ctx = new C_OrderedWrite(m_ictx->cct, result, trace, this);
+ ctx = util::create_async_context_callback(*m_ictx, ctx);
+
+ auto req = io::ObjectDispatchSpec::create_write(
+ m_ictx, io::OBJECT_DISPATCH_LAYER_CACHE, oid.name, object_no, off,
+ std::move(bl_copy), snapc, 0, journal_tid, trace, ctx);
+ req->object_dispatch_flags = (
+ io::OBJECT_DISPATCH_FLAG_FLUSH |
+ io::OBJECT_DISPATCH_FLAG_WILL_RETRY_ON_ERROR);
+ req->send();
+
+ return ++m_tid;
+ }
+
+
+ void LibrbdWriteback::overwrite_extent(const object_t& oid, uint64_t off,
+ uint64_t len,
+ ceph_tid_t original_journal_tid,
+ ceph_tid_t new_journal_tid) {
+ typedef std::vector<std::pair<uint64_t,uint64_t> > Extents;
+
+ ldout(m_ictx->cct, 20) << __func__ << ": " << oid << " "
+ << off << "~" << len << " "
+ << "journal_tid=" << original_journal_tid << ", "
+ << "new_journal_tid=" << new_journal_tid << dendl;
+
+ uint64_t object_no = oid_to_object_no(oid.name, m_ictx->object_prefix);
+
+ // all IO operations are flushed prior to closing the journal
+ ceph_assert(original_journal_tid != 0 && m_ictx->journal != NULL);
+
+ Extents file_extents;
+ Striper::extent_to_file(m_ictx->cct, &m_ictx->layout, object_no, off,
+ len, file_extents);
+ for (Extents::iterator it = file_extents.begin();
+ it != file_extents.end(); ++it) {
+ if (new_journal_tid != 0) {
+ // ensure new journal event is safely committed to disk before
+ // committing old event
+ m_ictx->journal->flush_event(
+ new_journal_tid, new C_CommitIOEventExtent(m_ictx,
+ original_journal_tid,
+ it->first, it->second));
+ } else {
+ m_ictx->journal->commit_io_event_extent(original_journal_tid, it->first,
+ it->second, 0);
+ }
+ }
+ }
+
+ void LibrbdWriteback::complete_writes(const std::string& oid)
+ {
+ ceph_assert(m_lock.is_locked());
+ std::queue<write_result_d*>& results = m_writes[oid];
+ ldout(m_ictx->cct, 20) << "complete_writes() oid " << oid << dendl;
+ std::list<write_result_d*> finished;
+
+ while (!results.empty()) {
+ write_result_d *result = results.front();
+ if (!result->done)
+ break;
+ finished.push_back(result);
+ results.pop();
+ }
+
+ if (results.empty())
+ m_writes.erase(oid);
+
+ for (std::list<write_result_d*>::iterator it = finished.begin();
+ it != finished.end(); ++it) {
+ write_result_d *result = *it;
+ ldout(m_ictx->cct, 20) << "complete_writes() completing " << result
+ << dendl;
+ result->oncommit->complete(result->ret);
+ delete result;
+ }
+ }
+}
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