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-rw-r--r--src/osdc/Journaler.cc1607
1 files changed, 1607 insertions, 0 deletions
diff --git a/src/osdc/Journaler.cc b/src/osdc/Journaler.cc
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--- /dev/null
+++ b/src/osdc/Journaler.cc
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+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation. See file COPYING.
+ *
+ */
+
+#include "common/perf_counters.h"
+#include "common/dout.h"
+#include "include/Context.h"
+#include "msg/Messenger.h"
+#include "osdc/Journaler.h"
+#include "common/errno.h"
+#include "include/ceph_assert.h"
+#include "common/Finisher.h"
+
+#define dout_subsys ceph_subsys_journaler
+#undef dout_prefix
+#define dout_prefix *_dout << objecter->messenger->get_myname() \
+ << ".journaler." << name << (readonly ? "(ro) ":"(rw) ")
+
+using std::chrono::seconds;
+
+
+class Journaler::C_DelayFlush : public Context {
+ Journaler *journaler;
+ public:
+ explicit C_DelayFlush(Journaler *j) : journaler(j) {}
+ void finish(int r) override {
+ journaler->_do_delayed_flush();
+ }
+};
+
+void Journaler::set_readonly()
+{
+ lock_guard l(lock);
+
+ ldout(cct, 1) << "set_readonly" << dendl;
+ readonly = true;
+}
+
+void Journaler::set_writeable()
+{
+ lock_guard l(lock);
+
+ ldout(cct, 1) << "set_writeable" << dendl;
+ readonly = false;
+}
+
+void Journaler::create(file_layout_t *l, stream_format_t const sf)
+{
+ lock_guard lk(lock);
+
+ ceph_assert(!readonly);
+ state = STATE_ACTIVE;
+
+ stream_format = sf;
+ journal_stream.set_format(sf);
+ _set_layout(l);
+
+ prezeroing_pos = prezero_pos = write_pos = flush_pos =
+ safe_pos = read_pos = requested_pos = received_pos =
+ expire_pos = trimming_pos = trimmed_pos =
+ next_safe_pos = layout.get_period();
+
+ ldout(cct, 1) << "created blank journal at inode 0x" << std::hex << ino
+ << std::dec << ", format=" << stream_format << dendl;
+}
+
+void Journaler::set_layout(file_layout_t const *l)
+{
+ lock_guard lk(lock);
+ _set_layout(l);
+}
+
+void Journaler::_set_layout(file_layout_t const *l)
+{
+ layout = *l;
+
+ if (layout.pool_id != pg_pool) {
+ // user can reset pool id through cephfs-journal-tool
+ lderr(cct) << "may got older pool id from header layout" << dendl;
+ ceph_abort();
+ }
+ last_written.layout = layout;
+ last_committed.layout = layout;
+
+ // prefetch intelligently.
+ // (watch out, this is big if you use big objects or weird striping)
+ uint64_t periods = cct->_conf.get_val<uint64_t>("journaler_prefetch_periods");
+ fetch_len = layout.get_period() * periods;
+}
+
+
+/***************** HEADER *******************/
+
+ostream& operator<<(ostream &out, const Journaler::Header &h)
+{
+ return out << "loghead(trim " << h.trimmed_pos
+ << ", expire " << h.expire_pos
+ << ", write " << h.write_pos
+ << ", stream_format " << (int)(h.stream_format)
+ << ")";
+}
+
+class Journaler::C_ReadHead : public Context {
+ Journaler *ls;
+public:
+ bufferlist bl;
+ explicit C_ReadHead(Journaler *l) : ls(l) {}
+ void finish(int r) override {
+ ls->_finish_read_head(r, bl);
+ }
+};
+
+class Journaler::C_RereadHead : public Context {
+ Journaler *ls;
+ Context *onfinish;
+public:
+ bufferlist bl;
+ C_RereadHead(Journaler *l, Context *onfinish_) : ls (l),
+ onfinish(onfinish_) {}
+ void finish(int r) override {
+ ls->_finish_reread_head(r, bl, onfinish);
+ }
+};
+
+class Journaler::C_ProbeEnd : public Context {
+ Journaler *ls;
+public:
+ uint64_t end;
+ explicit C_ProbeEnd(Journaler *l) : ls(l), end(-1) {}
+ void finish(int r) override {
+ ls->_finish_probe_end(r, end);
+ }
+};
+
+class Journaler::C_ReProbe : public Context {
+ Journaler *ls;
+ C_OnFinisher *onfinish;
+public:
+ uint64_t end;
+ C_ReProbe(Journaler *l, C_OnFinisher *onfinish_) :
+ ls(l), onfinish(onfinish_), end(0) {}
+ void finish(int r) override {
+ ls->_finish_reprobe(r, end, onfinish);
+ }
+};
+
+void Journaler::recover(Context *onread)
+{
+ lock_guard l(lock);
+ if (is_stopping()) {
+ onread->complete(-EAGAIN);
+ return;
+ }
+
+ ldout(cct, 1) << "recover start" << dendl;
+ ceph_assert(state != STATE_ACTIVE);
+ ceph_assert(readonly);
+
+ if (onread)
+ waitfor_recover.push_back(wrap_finisher(onread));
+
+ if (state != STATE_UNDEF) {
+ ldout(cct, 1) << "recover - already recovering" << dendl;
+ return;
+ }
+
+ ldout(cct, 1) << "read_head" << dendl;
+ state = STATE_READHEAD;
+ C_ReadHead *fin = new C_ReadHead(this);
+ _read_head(fin, &fin->bl);
+}
+
+void Journaler::_read_head(Context *on_finish, bufferlist *bl)
+{
+ // lock is locked
+ ceph_assert(state == STATE_READHEAD || state == STATE_REREADHEAD);
+
+ object_t oid = file_object_t(ino, 0);
+ object_locator_t oloc(pg_pool);
+ objecter->read_full(oid, oloc, CEPH_NOSNAP, bl, 0, wrap_finisher(on_finish));
+}
+
+void Journaler::reread_head(Context *onfinish)
+{
+ lock_guard l(lock);
+ _reread_head(wrap_finisher(onfinish));
+}
+
+/**
+ * Re-read the head from disk, and set the write_pos, expire_pos, trimmed_pos
+ * from the on-disk header. This switches the state to STATE_REREADHEAD for
+ * the duration, and you shouldn't start a re-read while other operations are
+ * in-flight, nor start other operations while a re-read is in progress.
+ * Also, don't call this until the Journaler has finished its recovery and has
+ * gone STATE_ACTIVE!
+ */
+void Journaler::_reread_head(Context *onfinish)
+{
+ ldout(cct, 10) << "reread_head" << dendl;
+ ceph_assert(state == STATE_ACTIVE);
+
+ state = STATE_REREADHEAD;
+ C_RereadHead *fin = new C_RereadHead(this, onfinish);
+ _read_head(fin, &fin->bl);
+}
+
+void Journaler::_finish_reread_head(int r, bufferlist& bl, Context *finish)
+{
+ lock_guard l(lock);
+ if (is_stopping()) {
+ finish->complete(-EAGAIN);
+ return;
+ }
+
+ //read on-disk header into
+ ceph_assert(bl.length() || r < 0 );
+
+ // unpack header
+ if (r == 0) {
+ Header h;
+ auto p = bl.cbegin();
+ try {
+ decode(h, p);
+ } catch (const buffer::error &e) {
+ finish->complete(-EINVAL);
+ return;
+ }
+ prezeroing_pos = prezero_pos = write_pos = flush_pos = safe_pos = next_safe_pos
+ = h.write_pos;
+ expire_pos = h.expire_pos;
+ trimmed_pos = trimming_pos = h.trimmed_pos;
+ init_headers(h);
+ state = STATE_ACTIVE;
+ }
+
+ finish->complete(r);
+}
+
+void Journaler::_finish_read_head(int r, bufferlist& bl)
+{
+ lock_guard l(lock);
+ if (is_stopping())
+ return;
+
+ ceph_assert(state == STATE_READHEAD);
+
+ if (r!=0) {
+ ldout(cct, 0) << "error getting journal off disk" << dendl;
+ list<Context*> ls;
+ ls.swap(waitfor_recover);
+ finish_contexts(cct, ls, r);
+ return;
+ }
+
+ if (bl.length() == 0) {
+ ldout(cct, 1) << "_finish_read_head r=" << r
+ << " read 0 bytes, assuming empty log" << dendl;
+ state = STATE_ACTIVE;
+ list<Context*> ls;
+ ls.swap(waitfor_recover);
+ finish_contexts(cct, ls, 0);
+ return;
+ }
+
+ // unpack header
+ bool corrupt = false;
+ Header h;
+ auto p = bl.cbegin();
+ try {
+ decode(h, p);
+
+ if (h.magic != magic) {
+ ldout(cct, 0) << "on disk magic '" << h.magic << "' != my magic '"
+ << magic << "'" << dendl;
+ corrupt = true;
+ } else if (h.write_pos < h.expire_pos || h.expire_pos < h.trimmed_pos) {
+ ldout(cct, 0) << "Corrupt header (bad offsets): " << h << dendl;
+ corrupt = true;
+ }
+ } catch (const buffer::error &e) {
+ corrupt = true;
+ }
+
+ if (corrupt) {
+ list<Context*> ls;
+ ls.swap(waitfor_recover);
+ finish_contexts(cct, ls, -EINVAL);
+ return;
+ }
+
+ prezeroing_pos = prezero_pos = write_pos = flush_pos = safe_pos = next_safe_pos
+ = h.write_pos;
+ read_pos = requested_pos = received_pos = expire_pos = h.expire_pos;
+ trimmed_pos = trimming_pos = h.trimmed_pos;
+
+ init_headers(h);
+ _set_layout(&h.layout);
+ stream_format = h.stream_format;
+ journal_stream.set_format(h.stream_format);
+
+ ldout(cct, 1) << "_finish_read_head " << h
+ << ". probing for end of log (from " << write_pos << ")..."
+ << dendl;
+ C_ProbeEnd *fin = new C_ProbeEnd(this);
+ state = STATE_PROBING;
+ _probe(fin, &fin->end);
+}
+
+void Journaler::_probe(Context *finish, uint64_t *end)
+{
+ // lock is locked
+ ldout(cct, 1) << "probing for end of the log" << dendl;
+ ceph_assert(state == STATE_PROBING || state == STATE_REPROBING);
+ // probe the log
+ filer.probe(ino, &layout, CEPH_NOSNAP,
+ write_pos, end, true, 0, wrap_finisher(finish));
+}
+
+void Journaler::_reprobe(C_OnFinisher *finish)
+{
+ ldout(cct, 10) << "reprobe" << dendl;
+ ceph_assert(state == STATE_ACTIVE);
+
+ state = STATE_REPROBING;
+ C_ReProbe *fin = new C_ReProbe(this, finish);
+ _probe(fin, &fin->end);
+}
+
+
+void Journaler::_finish_reprobe(int r, uint64_t new_end,
+ C_OnFinisher *onfinish)
+{
+ lock_guard l(lock);
+ if (is_stopping()) {
+ onfinish->complete(-EAGAIN);
+ return;
+ }
+
+ ceph_assert(new_end >= write_pos || r < 0);
+ ldout(cct, 1) << "_finish_reprobe new_end = " << new_end
+ << " (header had " << write_pos << ")."
+ << dendl;
+ prezeroing_pos = prezero_pos = write_pos = flush_pos = safe_pos = next_safe_pos = new_end;
+ state = STATE_ACTIVE;
+ onfinish->complete(r);
+}
+
+void Journaler::_finish_probe_end(int r, uint64_t end)
+{
+ lock_guard l(lock);
+ if (is_stopping())
+ return;
+
+ ceph_assert(state == STATE_PROBING);
+ if (r < 0) { // error in probing
+ goto out;
+ }
+ if (((int64_t)end) == -1) {
+ end = write_pos;
+ ldout(cct, 1) << "_finish_probe_end write_pos = " << end << " (header had "
+ << write_pos << "). log was empty. recovered." << dendl;
+ ceph_abort(); // hrm.
+ } else {
+ ceph_assert(end >= write_pos);
+ ldout(cct, 1) << "_finish_probe_end write_pos = " << end
+ << " (header had " << write_pos << "). recovered."
+ << dendl;
+ }
+
+ state = STATE_ACTIVE;
+
+ prezeroing_pos = prezero_pos = write_pos = flush_pos = safe_pos = next_safe_pos = end;
+
+out:
+ // done.
+ list<Context*> ls;
+ ls.swap(waitfor_recover);
+ finish_contexts(cct, ls, r);
+}
+
+class Journaler::C_RereadHeadProbe : public Context
+{
+ Journaler *ls;
+ C_OnFinisher *final_finish;
+public:
+ C_RereadHeadProbe(Journaler *l, C_OnFinisher *finish) :
+ ls(l), final_finish(finish) {}
+ void finish(int r) override {
+ ls->_finish_reread_head_and_probe(r, final_finish);
+ }
+};
+
+void Journaler::reread_head_and_probe(Context *onfinish)
+{
+ lock_guard l(lock);
+
+ ceph_assert(state == STATE_ACTIVE);
+ _reread_head(new C_RereadHeadProbe(this, wrap_finisher(onfinish)));
+}
+
+void Journaler::_finish_reread_head_and_probe(int r, C_OnFinisher *onfinish)
+{
+ // Expect to be called back from finish_reread_head, which already takes lock
+ // lock is locked
+ if (is_stopping()) {
+ onfinish->complete(-EAGAIN);
+ return;
+ }
+
+ // Let the caller know that the operation has failed or was intentionally
+ // failed since the caller has been blocklisted.
+ if (r == -EBLOCKLISTED) {
+ onfinish->complete(r);
+ return;
+ }
+
+ ceph_assert(!r); //if we get an error, we're boned
+ _reprobe(onfinish);
+}
+
+
+// WRITING
+
+class Journaler::C_WriteHead : public Context {
+public:
+ Journaler *ls;
+ Header h;
+ C_OnFinisher *oncommit;
+ C_WriteHead(Journaler *l, Header& h_, C_OnFinisher *c) : ls(l), h(h_),
+ oncommit(c) {}
+ void finish(int r) override {
+ ls->_finish_write_head(r, h, oncommit);
+ }
+};
+
+void Journaler::write_head(Context *oncommit)
+{
+ lock_guard l(lock);
+ _write_head(oncommit);
+}
+
+
+void Journaler::_write_head(Context *oncommit)
+{
+ ceph_assert(!readonly);
+ ceph_assert(state == STATE_ACTIVE);
+ last_written.trimmed_pos = trimmed_pos;
+ last_written.expire_pos = expire_pos;
+ last_written.unused_field = expire_pos;
+ last_written.write_pos = safe_pos;
+ last_written.stream_format = stream_format;
+ ldout(cct, 10) << "write_head " << last_written << dendl;
+
+ // Avoid persisting bad pointers in case of bugs
+ ceph_assert(last_written.write_pos >= last_written.expire_pos);
+ ceph_assert(last_written.expire_pos >= last_written.trimmed_pos);
+
+ last_wrote_head = ceph::real_clock::now();
+
+ bufferlist bl;
+ encode(last_written, bl);
+ SnapContext snapc;
+
+ object_t oid = file_object_t(ino, 0);
+ object_locator_t oloc(pg_pool);
+ objecter->write_full(oid, oloc, snapc, bl, ceph::real_clock::now(), 0,
+ wrap_finisher(new C_WriteHead(
+ this, last_written,
+ wrap_finisher(oncommit))),
+ 0, 0, write_iohint);
+}
+
+void Journaler::_finish_write_head(int r, Header &wrote,
+ C_OnFinisher *oncommit)
+{
+ lock_guard l(lock);
+
+ if (r < 0) {
+ lderr(cct) << "_finish_write_head got " << cpp_strerror(r) << dendl;
+ handle_write_error(r);
+ return;
+ }
+ ceph_assert(!readonly);
+ ldout(cct, 10) << "_finish_write_head " << wrote << dendl;
+ last_committed = wrote;
+ if (oncommit) {
+ oncommit->complete(r);
+ }
+
+ _trim(); // trim?
+}
+
+
+/***************** WRITING *******************/
+
+class Journaler::C_Flush : public Context {
+ Journaler *ls;
+ uint64_t start;
+ ceph::real_time stamp;
+public:
+ C_Flush(Journaler *l, int64_t s, ceph::real_time st)
+ : ls(l), start(s), stamp(st) {}
+ void finish(int r) override {
+ ls->_finish_flush(r, start, stamp);
+ }
+};
+
+void Journaler::_finish_flush(int r, uint64_t start, ceph::real_time stamp)
+{
+ lock_guard l(lock);
+ ceph_assert(!readonly);
+
+ if (r < 0) {
+ lderr(cct) << "_finish_flush got " << cpp_strerror(r) << dendl;
+ handle_write_error(r);
+ return;
+ }
+
+ ceph_assert(start < flush_pos);
+
+ // calc latency?
+ if (logger) {
+ ceph::timespan lat = ceph::real_clock::now() - stamp;
+ logger->tinc(logger_key_lat, lat);
+ }
+
+ // adjust safe_pos
+ auto it = pending_safe.find(start);
+ ceph_assert(it != pending_safe.end());
+ uint64_t min_next_safe_pos = pending_safe.begin()->second;
+ pending_safe.erase(it);
+ if (pending_safe.empty())
+ safe_pos = next_safe_pos;
+ else
+ safe_pos = min_next_safe_pos;
+
+ ldout(cct, 10) << "_finish_flush safe from " << start
+ << ", pending_safe " << pending_safe
+ << ", (prezeroing/prezero)/write/flush/safe positions now "
+ << "(" << prezeroing_pos << "/" << prezero_pos << ")/"
+ << write_pos << "/" << flush_pos << "/" << safe_pos
+ << dendl;
+
+ // kick waiters <= safe_pos
+ if (!waitfor_safe.empty()) {
+ list<Context*> ls;
+ while (!waitfor_safe.empty()) {
+ auto it = waitfor_safe.begin();
+ if (it->first > safe_pos)
+ break;
+ ls.splice(ls.end(), it->second);
+ waitfor_safe.erase(it);
+ }
+ finish_contexts(cct, ls);
+ }
+}
+
+
+
+uint64_t Journaler::append_entry(bufferlist& bl)
+{
+ unique_lock l(lock);
+
+ ceph_assert(!readonly);
+ uint32_t s = bl.length();
+
+ // append
+ size_t delta = bl.length() + journal_stream.get_envelope_size();
+ // write_buf space is nearly full
+ if (!write_buf_throttle.get_or_fail(delta)) {
+ l.unlock();
+ ldout(cct, 10) << "write_buf_throttle wait, delta " << delta << dendl;
+ write_buf_throttle.get(delta);
+ l.lock();
+ }
+ ldout(cct, 20) << "write_buf_throttle get, delta " << delta << dendl;
+ size_t wrote = journal_stream.write(bl, &write_buf, write_pos);
+ ldout(cct, 10) << "append_entry len " << s << " to " << write_pos << "~"
+ << wrote << dendl;
+ write_pos += wrote;
+
+ // flush previous object?
+ uint64_t su = get_layout_period();
+ ceph_assert(su > 0);
+ uint64_t write_off = write_pos % su;
+ uint64_t write_obj = write_pos / su;
+ uint64_t flush_obj = flush_pos / su;
+ if (write_obj != flush_obj) {
+ ldout(cct, 10) << " flushing completed object(s) (su " << su << " wro "
+ << write_obj << " flo " << flush_obj << ")" << dendl;
+ _do_flush(write_buf.length() - write_off);
+
+ // if _do_flush() skips flushing some data, it does do a best effort to
+ // update next_safe_pos.
+ if (write_buf.length() > 0 &&
+ write_buf.length() <= wrote) { // the unflushed data are within this entry
+ // set next_safe_pos to end of previous entry
+ next_safe_pos = write_pos - wrote;
+ }
+ }
+
+ return write_pos;
+}
+
+
+void Journaler::_do_flush(unsigned amount)
+{
+ if (is_stopping())
+ return;
+ if (write_pos == flush_pos)
+ return;
+ ceph_assert(write_pos > flush_pos);
+ ceph_assert(!readonly);
+
+ // flush
+ uint64_t len = write_pos - flush_pos;
+ ceph_assert(len == write_buf.length());
+ if (amount && amount < len)
+ len = amount;
+
+ // zero at least two full periods ahead. this ensures
+ // that the next object will not exist.
+ uint64_t period = get_layout_period();
+ if (flush_pos + len + 2*period > prezero_pos) {
+ _issue_prezero();
+
+ int64_t newlen = prezero_pos - flush_pos - period;
+ if (newlen <= 0) {
+ ldout(cct, 10) << "_do_flush wanted to do " << flush_pos << "~" << len
+ << " already too close to prezero_pos " << prezero_pos
+ << ", zeroing first" << dendl;
+ waiting_for_zero_pos = flush_pos + len;
+ return;
+ }
+ if (static_cast<uint64_t>(newlen) < len) {
+ ldout(cct, 10) << "_do_flush wanted to do " << flush_pos << "~" << len
+ << " but hit prezero_pos " << prezero_pos
+ << ", will do " << flush_pos << "~" << newlen << dendl;
+ waiting_for_zero_pos = flush_pos + len;
+ len = newlen;
+ }
+ }
+ ldout(cct, 10) << "_do_flush flushing " << flush_pos << "~" << len << dendl;
+
+ // submit write for anything pending
+ // flush _start_ pos to _finish_flush
+ ceph::real_time now = ceph::real_clock::now();
+ SnapContext snapc;
+
+ Context *onsafe = new C_Flush(this, flush_pos, now); // on COMMIT
+ pending_safe[flush_pos] = next_safe_pos;
+
+ bufferlist write_bl;
+
+ // adjust pointers
+ if (len == write_buf.length()) {
+ write_bl.swap(write_buf);
+ next_safe_pos = write_pos;
+ } else {
+ write_buf.splice(0, len, &write_bl);
+ // Keys of waitfor_safe map are journal entry boundaries.
+ // Try finding a journal entry that we are actually flushing
+ // and set next_safe_pos to end of it. This is best effort.
+ // The one we found may not be the lastest flushing entry.
+ auto p = waitfor_safe.lower_bound(flush_pos + len);
+ if (p != waitfor_safe.end()) {
+ if (p->first > flush_pos + len && p != waitfor_safe.begin())
+ --p;
+ if (p->first <= flush_pos + len && p->first > next_safe_pos)
+ next_safe_pos = p->first;
+ }
+ }
+
+ filer.write(ino, &layout, snapc,
+ flush_pos, len, write_bl, ceph::real_clock::now(),
+ 0,
+ wrap_finisher(onsafe), write_iohint);
+
+ flush_pos += len;
+ ceph_assert(write_buf.length() == write_pos - flush_pos);
+ write_buf_throttle.put(len);
+ ldout(cct, 20) << "write_buf_throttle put, len " << len << dendl;
+
+ ldout(cct, 10)
+ << "_do_flush (prezeroing/prezero)/write/flush/safe pointers now at "
+ << "(" << prezeroing_pos << "/" << prezero_pos << ")/" << write_pos
+ << "/" << flush_pos << "/" << safe_pos << dendl;
+
+ _issue_prezero();
+}
+
+
+void Journaler::wait_for_flush(Context *onsafe)
+{
+ lock_guard l(lock);
+ if (is_stopping()) {
+ if (onsafe)
+ onsafe->complete(-EAGAIN);
+ return;
+ }
+ _wait_for_flush(onsafe);
+}
+
+void Journaler::_wait_for_flush(Context *onsafe)
+{
+ ceph_assert(!readonly);
+
+ // all flushed and safe?
+ if (write_pos == safe_pos) {
+ ceph_assert(write_buf.length() == 0);
+ ldout(cct, 10)
+ << "flush nothing to flush, (prezeroing/prezero)/write/flush/safe "
+ "pointers at " << "(" << prezeroing_pos << "/" << prezero_pos << ")/"
+ << write_pos << "/" << flush_pos << "/" << safe_pos << dendl;
+ if (onsafe) {
+ finisher->queue(onsafe, 0);
+ }
+ return;
+ }
+
+ // queue waiter
+ if (onsafe) {
+ waitfor_safe[write_pos].push_back(wrap_finisher(onsafe));
+ }
+}
+
+void Journaler::flush(Context *onsafe)
+{
+ lock_guard l(lock);
+ if (is_stopping()) {
+ if (onsafe)
+ onsafe->complete(-EAGAIN);
+ return;
+ }
+ _flush(wrap_finisher(onsafe));
+}
+
+void Journaler::_flush(C_OnFinisher *onsafe)
+{
+ ceph_assert(!readonly);
+
+ if (write_pos == flush_pos) {
+ ceph_assert(write_buf.length() == 0);
+ ldout(cct, 10) << "flush nothing to flush, (prezeroing/prezero)/write/"
+ "flush/safe pointers at " << "(" << prezeroing_pos << "/" << prezero_pos
+ << ")/" << write_pos << "/" << flush_pos << "/" << safe_pos
+ << dendl;
+ if (onsafe) {
+ onsafe->complete(0);
+ }
+ } else {
+ _do_flush();
+ _wait_for_flush(onsafe);
+ }
+
+ // write head?
+ if (_write_head_needed()) {
+ _write_head();
+ }
+}
+
+bool Journaler::_write_head_needed()
+{
+ return last_wrote_head + seconds(cct->_conf.get_val<int64_t>("journaler_write_head_interval"))
+ < ceph::real_clock::now();
+}
+
+
+/*************** prezeroing ******************/
+
+struct C_Journaler_Prezero : public Context {
+ Journaler *journaler;
+ uint64_t from, len;
+ C_Journaler_Prezero(Journaler *j, uint64_t f, uint64_t l)
+ : journaler(j), from(f), len(l) {}
+ void finish(int r) override {
+ journaler->_finish_prezero(r, from, len);
+ }
+};
+
+void Journaler::_issue_prezero()
+{
+ ceph_assert(prezeroing_pos >= flush_pos);
+
+ uint64_t num_periods = cct->_conf.get_val<uint64_t>("journaler_prezero_periods");
+ /*
+ * issue zero requests based on write_pos, even though the invariant
+ * is that we zero ahead of flush_pos.
+ */
+ uint64_t period = get_layout_period();
+ uint64_t to = write_pos + period * num_periods + period - 1;
+ to -= to % period;
+
+ if (prezeroing_pos >= to) {
+ ldout(cct, 20) << "_issue_prezero target " << to << " <= prezeroing_pos "
+ << prezeroing_pos << dendl;
+ return;
+ }
+
+ while (prezeroing_pos < to) {
+ uint64_t len;
+ if (prezeroing_pos % period == 0) {
+ len = period;
+ ldout(cct, 10) << "_issue_prezero removing " << prezeroing_pos << "~"
+ << period << " (full period)" << dendl;
+ } else {
+ len = period - (prezeroing_pos % period);
+ ldout(cct, 10) << "_issue_prezero zeroing " << prezeroing_pos << "~"
+ << len << " (partial period)" << dendl;
+ }
+ SnapContext snapc;
+ Context *c = wrap_finisher(new C_Journaler_Prezero(this, prezeroing_pos,
+ len));
+ filer.zero(ino, &layout, snapc, prezeroing_pos, len,
+ ceph::real_clock::now(), 0, c);
+ prezeroing_pos += len;
+ }
+}
+
+// Lock cycle because we get called out of objecter callback (holding
+// objecter read lock), but there are also cases where we take the journaler
+// lock before calling into objecter to do I/O.
+void Journaler::_finish_prezero(int r, uint64_t start, uint64_t len)
+{
+ lock_guard l(lock);
+
+ ldout(cct, 10) << "_prezeroed to " << start << "~" << len
+ << ", prezeroing/prezero was " << prezeroing_pos << "/"
+ << prezero_pos << ", pending " << pending_zero
+ << dendl;
+ if (r < 0 && r != -ENOENT) {
+ lderr(cct) << "_prezeroed got " << cpp_strerror(r) << dendl;
+ handle_write_error(r);
+ return;
+ }
+
+ ceph_assert(r == 0 || r == -ENOENT);
+
+ if (start == prezero_pos) {
+ prezero_pos += len;
+ while (!pending_zero.empty() &&
+ pending_zero.begin().get_start() == prezero_pos) {
+ interval_set<uint64_t>::iterator b(pending_zero.begin());
+ prezero_pos += b.get_len();
+ pending_zero.erase(b);
+ }
+
+ if (waiting_for_zero_pos > flush_pos) {
+ _do_flush(waiting_for_zero_pos - flush_pos);
+ }
+
+ if (prezero_pos == prezeroing_pos &&
+ !waitfor_prezero.empty()) {
+ list<Context*> ls;
+ ls.swap(waitfor_prezero);
+ finish_contexts(cct, ls, 0);
+ }
+ } else {
+ pending_zero.insert(start, len);
+ }
+ ldout(cct, 10) << "_prezeroed prezeroing/prezero now " << prezeroing_pos
+ << "/" << prezero_pos
+ << ", pending " << pending_zero
+ << dendl;
+}
+
+void Journaler::wait_for_prezero(Context *onfinish)
+{
+ ceph_assert(onfinish);
+ lock_guard l(lock);
+
+ if (prezero_pos == prezeroing_pos) {
+ finisher->queue(onfinish, 0);
+ return;
+ }
+ waitfor_prezero.push_back(wrap_finisher(onfinish));
+}
+
+
+/***************** READING *******************/
+
+
+class Journaler::C_Read : public Context {
+ Journaler *ls;
+ uint64_t offset;
+ uint64_t length;
+public:
+ bufferlist bl;
+ C_Read(Journaler *j, uint64_t o, uint64_t l) : ls(j), offset(o), length(l) {}
+ void finish(int r) override {
+ ls->_finish_read(r, offset, length, bl);
+ }
+};
+
+class Journaler::C_RetryRead : public Context {
+ Journaler *ls;
+public:
+ explicit C_RetryRead(Journaler *l) : ls(l) {}
+
+ void finish(int r) override {
+ // Should only be called from waitfor_safe i.e. already inside lock
+ // (ls->lock is locked
+ ls->_prefetch();
+ }
+};
+
+void Journaler::_finish_read(int r, uint64_t offset, uint64_t length,
+ bufferlist& bl)
+{
+ lock_guard l(lock);
+
+ if (r < 0) {
+ ldout(cct, 0) << "_finish_read got error " << r << dendl;
+ error = r;
+ } else {
+ ldout(cct, 10) << "_finish_read got " << offset << "~" << bl.length()
+ << dendl;
+ if (bl.length() < length) {
+ ldout(cct, 0) << "_finish_read got less than expected (" << length << ")"
+ << dendl;
+ error = -EINVAL;
+ }
+ }
+
+ if (error) {
+ if (on_readable) {
+ C_OnFinisher *f = on_readable;
+ on_readable = 0;
+ f->complete(error);
+ }
+ return;
+ }
+
+ prefetch_buf[offset].swap(bl);
+
+ try {
+ _assimilate_prefetch();
+ } catch (const buffer::error &err) {
+ lderr(cct) << "_decode error from assimilate_prefetch" << dendl;
+ error = -EINVAL;
+ if (on_readable) {
+ C_OnFinisher *f = on_readable;
+ on_readable = 0;
+ f->complete(error);
+ }
+ return;
+ }
+ _prefetch();
+}
+
+void Journaler::_assimilate_prefetch()
+{
+ bool was_readable = readable;
+
+ bool got_any = false;
+ while (!prefetch_buf.empty()) {
+ map<uint64_t,bufferlist>::iterator p = prefetch_buf.begin();
+ if (p->first != received_pos) {
+ uint64_t gap = p->first - received_pos;
+ ldout(cct, 10) << "_assimilate_prefetch gap of " << gap
+ << " from received_pos " << received_pos
+ << " to first prefetched buffer " << p->first << dendl;
+ break;
+ }
+
+ ldout(cct, 10) << "_assimilate_prefetch " << p->first << "~"
+ << p->second.length() << dendl;
+ received_pos += p->second.length();
+ read_buf.claim_append(p->second);
+ ceph_assert(received_pos <= requested_pos);
+ prefetch_buf.erase(p);
+ got_any = true;
+ }
+
+ if (got_any) {
+ ldout(cct, 10) << "_assimilate_prefetch read_buf now " << read_pos << "~"
+ << read_buf.length() << ", read pointers read_pos=" << read_pos
+ << " received_pos=" << received_pos << " requested_pos=" << requested_pos
+ << dendl;
+
+ // Update readability (this will also hit any decode errors resulting
+ // from bad data)
+ readable = _is_readable();
+ }
+
+ if ((got_any && !was_readable && readable) || read_pos == write_pos) {
+ // readable!
+ ldout(cct, 10) << "_finish_read now readable (or at journal end) readable="
+ << readable << " read_pos=" << read_pos << " write_pos="
+ << write_pos << dendl;
+ if (on_readable) {
+ C_OnFinisher *f = on_readable;
+ on_readable = 0;
+ f->complete(0);
+ }
+ }
+}
+
+void Journaler::_issue_read(uint64_t len)
+{
+ // stuck at safe_pos? (this is needed if we are reading the tail of
+ // a journal we are also writing to)
+ ceph_assert(requested_pos <= safe_pos);
+ if (requested_pos == safe_pos) {
+ ldout(cct, 10) << "_issue_read requested_pos = safe_pos = " << safe_pos
+ << ", waiting" << dendl;
+ ceph_assert(write_pos > requested_pos);
+ if (pending_safe.empty()) {
+ _flush(NULL);
+ }
+
+ // Make sure keys of waitfor_safe map are journal entry boundaries.
+ // The key we used here is either next_safe_pos or old value of
+ // next_safe_pos. next_safe_pos is always set to journal entry
+ // boundary.
+ auto p = pending_safe.rbegin();
+ if (p != pending_safe.rend())
+ waitfor_safe[p->second].push_back(new C_RetryRead(this));
+ else
+ waitfor_safe[next_safe_pos].push_back(new C_RetryRead(this));
+ return;
+ }
+
+ // don't read too much
+ if (requested_pos + len > safe_pos) {
+ len = safe_pos - requested_pos;
+ ldout(cct, 10) << "_issue_read reading only up to safe_pos " << safe_pos
+ << dendl;
+ }
+
+ // go.
+ ldout(cct, 10) << "_issue_read reading " << requested_pos << "~" << len
+ << ", read pointers read_pos=" << read_pos << " received_pos=" << received_pos
+ << " requested_pos+len=" << (requested_pos+len) << dendl;
+
+ // step by period (object). _don't_ do a single big filer.read()
+ // here because it will wait for all object reads to complete before
+ // giving us back any data. this way we can process whatever bits
+ // come in that are contiguous.
+ uint64_t period = get_layout_period();
+ while (len > 0) {
+ uint64_t e = requested_pos + period;
+ e -= e % period;
+ uint64_t l = e - requested_pos;
+ if (l > len)
+ l = len;
+ C_Read *c = new C_Read(this, requested_pos, l);
+ filer.read(ino, &layout, CEPH_NOSNAP, requested_pos, l, &c->bl, 0,
+ wrap_finisher(c), CEPH_OSD_OP_FLAG_FADVISE_DONTNEED);
+ requested_pos += l;
+ len -= l;
+ }
+}
+
+void Journaler::_prefetch()
+{
+ if (is_stopping())
+ return;
+
+ ldout(cct, 10) << "_prefetch" << dendl;
+ // prefetch
+ uint64_t pf;
+ if (temp_fetch_len) {
+ ldout(cct, 10) << "_prefetch temp_fetch_len " << temp_fetch_len << dendl;
+ pf = temp_fetch_len;
+ temp_fetch_len = 0;
+ } else {
+ pf = fetch_len;
+ }
+
+ uint64_t raw_target = read_pos + pf;
+
+ // read full log segments, so increase if necessary
+ uint64_t period = get_layout_period();
+ uint64_t remainder = raw_target % period;
+ uint64_t adjustment = remainder ? period - remainder : 0;
+ uint64_t target = raw_target + adjustment;
+
+ // don't read past the log tail
+ if (target > write_pos)
+ target = write_pos;
+
+ if (requested_pos < target) {
+ uint64_t len = target - requested_pos;
+ ldout(cct, 10) << "_prefetch " << pf << " requested_pos " << requested_pos
+ << " < target " << target << " (" << raw_target
+ << "), prefetching " << len << dendl;
+
+ if (pending_safe.empty() && write_pos > safe_pos) {
+ // If we are reading and writing the journal, then we may need
+ // to issue a flush if one isn't already in progress.
+ // Avoid doing a flush every time so that if we do write/read/write/read
+ // we don't end up flushing after every write.
+ ldout(cct, 10) << "_prefetch: requested_pos=" << requested_pos
+ << ", read_pos=" << read_pos
+ << ", write_pos=" << write_pos
+ << ", safe_pos=" << safe_pos << dendl;
+ _do_flush();
+ }
+
+ _issue_read(len);
+ }
+}
+
+
+/*
+ * _is_readable() - return true if next entry is ready.
+ */
+bool Journaler::_is_readable()
+{
+ // anything to read?
+ if (read_pos == write_pos)
+ return false;
+
+ // Check if the retrieve bytestream has enough for an entry
+ uint64_t need;
+ if (journal_stream.readable(read_buf, &need)) {
+ return true;
+ }
+
+ ldout (cct, 10) << "_is_readable read_buf.length() == " << read_buf.length()
+ << ", but need " << need << " for next entry; fetch_len is "
+ << fetch_len << dendl;
+
+ // partial fragment at the end?
+ if (received_pos == write_pos) {
+ ldout(cct, 10) << "is_readable() detected partial entry at tail, "
+ "adjusting write_pos to " << read_pos << dendl;
+
+ // adjust write_pos
+ prezeroing_pos = prezero_pos = write_pos = flush_pos = safe_pos = next_safe_pos = read_pos;
+ ceph_assert(write_buf.length() == 0);
+ ceph_assert(waitfor_safe.empty());
+
+ // reset read state
+ requested_pos = received_pos = read_pos;
+ read_buf.clear();
+
+ // FIXME: truncate on disk?
+
+ return false;
+ }
+
+ if (need > fetch_len) {
+ temp_fetch_len = need;
+ ldout(cct, 10) << "_is_readable noting temp_fetch_len " << temp_fetch_len
+ << dendl;
+ }
+
+ ldout(cct, 10) << "_is_readable: not readable, returning false" << dendl;
+ return false;
+}
+
+/*
+ * is_readable() - kickstart prefetch, too
+ */
+bool Journaler::is_readable()
+{
+ lock_guard l(lock);
+
+ if (error != 0) {
+ return false;
+ }
+
+ bool r = readable;
+ _prefetch();
+ return r;
+}
+
+class Journaler::C_EraseFinish : public Context {
+ Journaler *journaler;
+ C_OnFinisher *completion;
+ public:
+ C_EraseFinish(Journaler *j, C_OnFinisher *c) : journaler(j), completion(c) {}
+ void finish(int r) override {
+ journaler->_finish_erase(r, completion);
+ }
+};
+
+/**
+ * Entirely erase the journal, including header. For use when you
+ * have already made a copy of the journal somewhere else.
+ */
+void Journaler::erase(Context *completion)
+{
+ lock_guard l(lock);
+
+ // Async delete the journal data
+ uint64_t first = trimmed_pos / get_layout_period();
+ uint64_t num = (write_pos - trimmed_pos) / get_layout_period() + 2;
+ filer.purge_range(ino, &layout, SnapContext(), first, num,
+ ceph::real_clock::now(), 0,
+ wrap_finisher(new C_EraseFinish(
+ this, wrap_finisher(completion))));
+
+ // We will not start the operation to delete the header until
+ // _finish_erase has seen the data deletion succeed: otherwise if
+ // there was an error deleting data we might prematurely delete the
+ // header thereby lose our reference to the data.
+}
+
+void Journaler::_finish_erase(int data_result, C_OnFinisher *completion)
+{
+ lock_guard l(lock);
+ if (is_stopping()) {
+ completion->complete(-EAGAIN);
+ return;
+ }
+
+ if (data_result == 0) {
+ // Async delete the journal header
+ filer.purge_range(ino, &layout, SnapContext(), 0, 1,
+ ceph::real_clock::now(),
+ 0, wrap_finisher(completion));
+ } else {
+ lderr(cct) << "Failed to delete journal " << ino << " data: "
+ << cpp_strerror(data_result) << dendl;
+ completion->complete(data_result);
+ }
+}
+
+/* try_read_entry(bl)
+ * read entry into bl if it's ready.
+ * otherwise, do nothing.
+ */
+bool Journaler::try_read_entry(bufferlist& bl)
+{
+ lock_guard l(lock);
+
+ if (!readable) {
+ ldout(cct, 10) << "try_read_entry at " << read_pos << " not readable"
+ << dendl;
+ return false;
+ }
+
+ uint64_t start_ptr;
+ size_t consumed;
+ try {
+ consumed = journal_stream.read(read_buf, &bl, &start_ptr);
+ if (stream_format >= JOURNAL_FORMAT_RESILIENT) {
+ ceph_assert(start_ptr == read_pos);
+ }
+ } catch (const buffer::error &e) {
+ lderr(cct) << __func__ << ": decode error from journal_stream" << dendl;
+ error = -EINVAL;
+ return false;
+ }
+
+ ldout(cct, 10) << "try_read_entry at " << read_pos << " read "
+ << read_pos << "~" << consumed << " (have "
+ << read_buf.length() << ")" << dendl;
+
+ read_pos += consumed;
+ try {
+ // We were readable, we might not be any more
+ readable = _is_readable();
+ } catch (const buffer::error &e) {
+ lderr(cct) << __func__ << ": decode error from _is_readable" << dendl;
+ error = -EINVAL;
+ return false;
+ }
+
+ // prefetch?
+ _prefetch();
+
+ // If bufferlist consists of discontiguous memory, decoding types whose
+ // denc_traits needs contiguous memory is inefficient. The bufferlist may
+ // get copied to temporary memory multiple times (copy_shallow() in
+ // src/include/denc.h actually does deep copy)
+ if (bl.get_num_buffers() > 1)
+ bl.rebuild();
+ return true;
+}
+
+void Journaler::wait_for_readable(Context *onreadable)
+{
+ lock_guard l(lock);
+ if (is_stopping()) {
+ finisher->queue(onreadable, -EAGAIN);
+ return;
+ }
+
+ ceph_assert(on_readable == 0);
+ if (!readable) {
+ ldout(cct, 10) << "wait_for_readable at " << read_pos << " onreadable "
+ << onreadable << dendl;
+ on_readable = wrap_finisher(onreadable);
+ } else {
+ // race with OSD reply
+ finisher->queue(onreadable, 0);
+ }
+}
+
+bool Journaler::have_waiter() const
+{
+ return on_readable != nullptr;
+}
+
+
+
+
+/***************** TRIMMING *******************/
+
+
+class Journaler::C_Trim : public Context {
+ Journaler *ls;
+ uint64_t to;
+public:
+ C_Trim(Journaler *l, int64_t t) : ls(l), to(t) {}
+ void finish(int r) override {
+ ls->_finish_trim(r, to);
+ }
+};
+
+void Journaler::trim()
+{
+ lock_guard l(lock);
+ _trim();
+}
+
+void Journaler::_trim()
+{
+ if (is_stopping())
+ return;
+
+ ceph_assert(!readonly);
+ uint64_t period = get_layout_period();
+ uint64_t trim_to = last_committed.expire_pos;
+ trim_to -= trim_to % period;
+ ldout(cct, 10) << "trim last_commited head was " << last_committed
+ << ", can trim to " << trim_to
+ << dendl;
+ if (trim_to == 0 || trim_to == trimming_pos) {
+ ldout(cct, 10) << "trim already trimmed/trimming to "
+ << trimmed_pos << "/" << trimming_pos << dendl;
+ return;
+ }
+
+ if (trimming_pos > trimmed_pos) {
+ ldout(cct, 10) << "trim already trimming atm, try again later. "
+ "trimmed/trimming is " << trimmed_pos << "/" << trimming_pos << dendl;
+ return;
+ }
+
+ // trim
+ ceph_assert(trim_to <= write_pos);
+ ceph_assert(trim_to <= expire_pos);
+ ceph_assert(trim_to > trimming_pos);
+ ldout(cct, 10) << "trim trimming to " << trim_to
+ << ", trimmed/trimming/expire are "
+ << trimmed_pos << "/" << trimming_pos << "/" << expire_pos
+ << dendl;
+
+ // delete range of objects
+ uint64_t first = trimming_pos / period;
+ uint64_t num = (trim_to - trimming_pos) / period;
+ SnapContext snapc;
+ filer.purge_range(ino, &layout, snapc, first, num,
+ ceph::real_clock::now(), 0,
+ wrap_finisher(new C_Trim(this, trim_to)));
+ trimming_pos = trim_to;
+}
+
+void Journaler::_finish_trim(int r, uint64_t to)
+{
+ lock_guard l(lock);
+
+ ceph_assert(!readonly);
+ ldout(cct, 10) << "_finish_trim trimmed_pos was " << trimmed_pos
+ << ", trimmed/trimming/expire now "
+ << to << "/" << trimming_pos << "/" << expire_pos
+ << dendl;
+ if (r < 0 && r != -ENOENT) {
+ lderr(cct) << "_finish_trim got " << cpp_strerror(r) << dendl;
+ handle_write_error(r);
+ return;
+ }
+
+ ceph_assert(r >= 0 || r == -ENOENT);
+
+ ceph_assert(to <= trimming_pos);
+ ceph_assert(to > trimmed_pos);
+ trimmed_pos = to;
+}
+
+void Journaler::handle_write_error(int r)
+{
+ // lock is locked
+
+ lderr(cct) << "handle_write_error " << cpp_strerror(r) << dendl;
+ if (on_write_error) {
+ on_write_error->complete(r);
+ on_write_error = NULL;
+ called_write_error = true;
+ } else if (called_write_error) {
+ /* We don't call error handler more than once, subsequent errors
+ * are dropped -- this is okay as long as the error handler does
+ * something dramatic like respawn */
+ lderr(cct) << __func__ << ": multiple write errors, handler already called"
+ << dendl;
+ } else {
+ ceph_abort_msg("unhandled write error");
+ }
+}
+
+
+/**
+ * Test whether the 'read_buf' byte stream has enough data to read
+ * an entry
+ *
+ * sets 'next_envelope_size' to the number of bytes needed to advance (enough
+ * to get the next header if header was unavailable, or enough to get the whole
+ * next entry if the header was available but the body wasn't).
+ */
+bool JournalStream::readable(bufferlist &read_buf, uint64_t *need) const
+{
+ ceph_assert(need != NULL);
+
+ uint32_t entry_size = 0;
+ uint64_t entry_sentinel = 0;
+ auto p = read_buf.cbegin();
+
+ // Do we have enough data to decode an entry prefix?
+ if (format >= JOURNAL_FORMAT_RESILIENT) {
+ *need = sizeof(entry_size) + sizeof(entry_sentinel);
+ } else {
+ *need = sizeof(entry_size);
+ }
+ if (read_buf.length() >= *need) {
+ if (format >= JOURNAL_FORMAT_RESILIENT) {
+ decode(entry_sentinel, p);
+ if (entry_sentinel != sentinel) {
+ throw buffer::malformed_input("Invalid sentinel");
+ }
+ }
+
+ decode(entry_size, p);
+ } else {
+ return false;
+ }
+
+ // Do we have enough data to decode an entry prefix, payload and suffix?
+ if (format >= JOURNAL_FORMAT_RESILIENT) {
+ *need = JOURNAL_ENVELOPE_RESILIENT + entry_size;
+ } else {
+ *need = JOURNAL_ENVELOPE_LEGACY + entry_size;
+ }
+ if (read_buf.length() >= *need) {
+ return true; // No more bytes needed
+ }
+
+ return false;
+}
+
+
+/**
+ * Consume one entry from a journal byte stream 'from', splicing a
+ * serialized LogEvent blob into 'entry'.
+ *
+ * 'entry' must be non null and point to an empty bufferlist.
+ *
+ * 'from' must contain sufficient valid data (i.e. readable is true).
+ *
+ * 'start_ptr' will be set to the entry's start pointer, if the collection
+ * format provides it. It may not be null.
+ *
+ * @returns The number of bytes consumed from the `from` byte stream. Note
+ * that this is not equal to the length of `entry`, which contains
+ * the inner serialized LogEvent and not the envelope.
+ */
+size_t JournalStream::read(bufferlist &from, bufferlist *entry,
+ uint64_t *start_ptr)
+{
+ ceph_assert(start_ptr != NULL);
+ ceph_assert(entry != NULL);
+ ceph_assert(entry->length() == 0);
+
+ uint32_t entry_size = 0;
+
+ // Consume envelope prefix: entry_size and entry_sentinel
+ auto from_ptr = from.cbegin();
+ if (format >= JOURNAL_FORMAT_RESILIENT) {
+ uint64_t entry_sentinel = 0;
+ decode(entry_sentinel, from_ptr);
+ // Assertion instead of clean check because of precondition of this
+ // fn is that readable() already passed
+ ceph_assert(entry_sentinel == sentinel);
+ }
+ decode(entry_size, from_ptr);
+
+ // Read out the payload
+ from_ptr.copy(entry_size, *entry);
+
+ // Consume the envelope suffix (start_ptr)
+ if (format >= JOURNAL_FORMAT_RESILIENT) {
+ decode(*start_ptr, from_ptr);
+ } else {
+ *start_ptr = 0;
+ }
+
+ // Trim the input buffer to discard the bytes we have consumed
+ from.splice(0, from_ptr.get_off());
+
+ return from_ptr.get_off();
+}
+
+
+/**
+ * Append one entry
+ */
+size_t JournalStream::write(bufferlist &entry, bufferlist *to,
+ uint64_t const &start_ptr)
+{
+ ceph_assert(to != NULL);
+
+ uint32_t const entry_size = entry.length();
+ if (format >= JOURNAL_FORMAT_RESILIENT) {
+ encode(sentinel, *to);
+ }
+ encode(entry_size, *to);
+ to->claim_append(entry);
+ if (format >= JOURNAL_FORMAT_RESILIENT) {
+ encode(start_ptr, *to);
+ }
+
+ if (format >= JOURNAL_FORMAT_RESILIENT) {
+ return JOURNAL_ENVELOPE_RESILIENT + entry_size;
+ } else {
+ return JOURNAL_ENVELOPE_LEGACY + entry_size;
+ }
+}
+
+/**
+ * set write error callback
+ *
+ * Set a callback/context to trigger if we get a write error from
+ * the objecter. This may be from an explicit request (e.g., flush)
+ * or something async the journaler did on its own (e.g., journal
+ * header update).
+ *
+ * It is only used once; if the caller continues to use the
+ * Journaler and wants to hear about errors, it needs to reset the
+ * error_handler.
+ *
+ * @param c callback/context to trigger on error
+ */
+void Journaler::set_write_error_handler(Context *c) {
+ lock_guard l(lock);
+ ceph_assert(!on_write_error);
+ on_write_error = wrap_finisher(c);
+ called_write_error = false;
+}
+
+
+/**
+ * Wrap a context in a C_OnFinisher, if it is non-NULL
+ *
+ * Utility function to avoid lots of error-prone and verbose
+ * NULL checking on contexts passed in.
+ */
+C_OnFinisher *Journaler::wrap_finisher(Context *c)
+{
+ if (c != NULL) {
+ return new C_OnFinisher(c, finisher);
+ } else {
+ return NULL;
+ }
+}
+
+void Journaler::shutdown()
+{
+ lock_guard l(lock);
+
+ ldout(cct, 1) << __func__ << dendl;
+
+ state = STATE_STOPPING;
+ readable = false;
+
+ // Kick out anyone reading from journal
+ error = -EAGAIN;
+ if (on_readable) {
+ C_OnFinisher *f = on_readable;
+ on_readable = 0;
+ f->complete(-EAGAIN);
+ }
+
+ list<Context*> ls;
+ ls.swap(waitfor_recover);
+ finish_contexts(cct, ls, -ESHUTDOWN);
+
+ std::map<uint64_t, std::list<Context*> >::iterator i;
+ for (i = waitfor_safe.begin(); i != waitfor_safe.end(); ++i) {
+ finish_contexts(cct, i->second, -EAGAIN);
+ }
+ waitfor_safe.clear();
+}
+