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Diffstat (limited to 'classllfio__v2__xxx_1_1algorithm_1_1shared__fs__mutex_1_1atomic__append.html')
| -rw-r--r-- | classllfio__v2__xxx_1_1algorithm_1_1shared__fs__mutex_1_1atomic__append.html | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/classllfio__v2__xxx_1_1algorithm_1_1shared__fs__mutex_1_1atomic__append.html b/classllfio__v2__xxx_1_1algorithm_1_1shared__fs__mutex_1_1atomic__append.html index 483dbafa..23c966b2 100644 --- a/classllfio__v2__xxx_1_1algorithm_1_1shared__fs__mutex_1_1atomic__append.html +++ b/classllfio__v2__xxx_1_1algorithm_1_1shared__fs__mutex_1_1atomic__append.html @@ -204,7 +204,7 @@ Protected Member Functions</h2></td></tr> <li>Similarly older operating systems (e.g. Linux < 3.0) do not implement extent hole punching and therefore will also see excessive disk space consumption. Note at the time of writing OS X doesn't implement hole punching at all.</li> <li>If your OS doesn't have sane byte range locks (OS X, BSD, older Linuxes) and multiple objects in your process use the same lock file, misoperation will occur. Use lock_files instead.</li> </ul> -<dl class="todo"><dt><b><a class="el" href="todo.html#_todo000007">Todo:</a></b></dt><dd><p class="startdd">Implement hole punching once I port that code from LLFIO v1. </p> +<dl class="todo"><dt><b><a class="el" href="todo.html#_todo000006">Todo:</a></b></dt><dd><p class="startdd">Implement hole punching once I port that code from LLFIO v1. </p> <p>Decide on some resolution mechanism for sudden process exit. </p> <p class="enddd">There is a 1 out of 2^64-2 chance of unique id collision. It would be nice if we actually formally checked that our chosen unique id is actually unique. </p> </dd></dl> @@ -248,7 +248,7 @@ Protected Member Functions</h2></td></tr> </tr> </table> </div><div class="memdoc"> -<dl class="todo"><dt><b><a class="el" href="todo.html#_todo000009">Todo:</a></b></dt><dd>Read from header.last_known_good immediately if possible in order to avoid a duplicate read later </dd></dl> +<dl class="todo"><dt><b><a class="el" href="todo.html#_todo000008">Todo:</a></b></dt><dd>Read from header.last_known_good immediately if possible in order to avoid a duplicate read later </dd></dl> <p>Implements <a class="el" href="classllfio__v2__xxx_1_1algorithm_1_1shared__fs__mutex_1_1shared__fs__mutex.html">llfio_v2_xxx::algorithm::shared_fs_mutex::shared_fs_mutex</a>.</p> <div class="fragment"><div class="line"><a name="l00249"></a><span class="lineno"> 249</span>  {</div><div class="line"><a name="l00250"></a><span class="lineno"> 250</span>  LLFIO_LOG_FUNCTION_CALL(<span class="keyword">this</span>);</div><div class="line"><a name="l00251"></a><span class="lineno"> 251</span>  atomic_append_detail::lock_request lock_request;</div><div class="line"><a name="l00252"></a><span class="lineno"> 252</span>  <span class="keywordflow">if</span>(out.entities.size() > <span class="keyword">sizeof</span>(lock_request.entities) / <span class="keyword">sizeof</span>(lock_request.entities[0]))</div><div class="line"><a name="l00253"></a><span class="lineno"> 253</span>  {</div><div class="line"><a name="l00254"></a><span class="lineno"> 254</span>  <span class="keywordflow">return</span> errc::argument_list_too_long;</div><div class="line"><a name="l00255"></a><span class="lineno"> 255</span>  }</div><div class="line"><a name="l00256"></a><span class="lineno"> 256</span> </div><div class="line"><a name="l00257"></a><span class="lineno"> 257</span>  std::chrono::steady_clock::time_point began_steady;</div><div class="line"><a name="l00258"></a><span class="lineno"> 258</span>  std::chrono::system_clock::time_point end_utc;</div><div class="line"><a name="l00259"></a><span class="lineno"> 259</span>  <span class="keywordflow">if</span>(d)</div><div class="line"><a name="l00260"></a><span class="lineno"> 260</span>  {</div><div class="line"><a name="l00261"></a><span class="lineno"> 261</span>  <span class="keywordflow">if</span>((d).steady)</div><div class="line"><a name="l00262"></a><span class="lineno"> 262</span>  {</div><div class="line"><a name="l00263"></a><span class="lineno"> 263</span>  began_steady = std::chrono::steady_clock::now();</div><div class="line"><a name="l00264"></a><span class="lineno"> 264</span>  }</div><div class="line"><a name="l00265"></a><span class="lineno"> 265</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00266"></a><span class="lineno"> 266</span>  {</div><div class="line"><a name="l00267"></a><span class="lineno"> 267</span>  end_utc = (d).to_time_point();</div><div class="line"><a name="l00268"></a><span class="lineno"> 268</span>  }</div><div class="line"><a name="l00269"></a><span class="lineno"> 269</span>  }</div><div class="line"><a name="l00270"></a><span class="lineno"> 270</span>  <span class="comment">// Fire this if an error occurs</span></div><div class="line"><a name="l00271"></a><span class="lineno"> 271</span>  <span class="keyword">auto</span> disableunlock = undoer([&] { out.release(); });</div><div class="line"><a name="l00272"></a><span class="lineno"> 272</span> </div><div class="line"><a name="l00273"></a><span class="lineno"> 273</span>  <span class="comment">// Write my lock request immediately</span></div><div class="line"><a name="l00274"></a><span class="lineno"> 274</span>  memset(&lock_request, 0, <span class="keyword">sizeof</span>(lock_request));</div><div class="line"><a name="l00275"></a><span class="lineno"> 275</span>  lock_request.unique_id = _unique_id;</div><div class="line"><a name="l00276"></a><span class="lineno"> 276</span>  <span class="keyword">auto</span> count = std::chrono::system_clock::now() - std::chrono::system_clock::from_time_t(_header.time_offset);</div><div class="line"><a name="l00277"></a><span class="lineno"> 277</span>  lock_request.us_count = std::chrono::duration_cast<std::chrono::microseconds>(count).count();</div><div class="line"><a name="l00278"></a><span class="lineno"> 278</span>  lock_request.items = out.entities.size();</div><div class="line"><a name="l00279"></a><span class="lineno"> 279</span>  memcpy(lock_request.entities, out.entities.data(), <span class="keyword">sizeof</span>(lock_request.entities[0]) * out.entities.size());</div><div class="line"><a name="l00280"></a><span class="lineno"> 280</span>  <span class="keywordflow">if</span>(!_skip_hashing)</div><div class="line"><a name="l00281"></a><span class="lineno"> 281</span>  {</div><div class="line"><a name="l00282"></a><span class="lineno"> 282</span>  lock_request.hash = QUICKCPPLIB_NAMESPACE::algorithm::hash::fast_hash::hash((reinterpret_cast<char *>(&lock_request)) + 16, <span class="keyword">sizeof</span>(lock_request) - 16);</div><div class="line"><a name="l00283"></a><span class="lineno"> 283</span>  }</div><div class="line"><a name="l00284"></a><span class="lineno"> 284</span>  <span class="comment">// My lock request will be the file's current length or higher</span></div><div class="line"><a name="l00285"></a><span class="lineno"> 285</span>  OUTCOME_TRY(my_lock_request_offset, _h.<a class="code" href="classllfio__v2__xxx_1_1file__handle.html#a7991af58283025b80a7225866643f0b4">maximum_extent</a>());</div><div class="line"><a name="l00286"></a><span class="lineno"> 286</span>  {</div><div class="line"><a name="l00287"></a><span class="lineno"> 287</span>  OUTCOME_TRYV(_h.<a class="code" href="classllfio__v2__xxx_1_1handle.html#a101620e9fff0c0e8c346af0e9de58b6a">set_append_only</a>(<span class="keyword">true</span>));</div><div class="line"><a name="l00288"></a><span class="lineno"> 288</span>  <span class="keyword">auto</span> undo = undoer([<span class="keyword">this</span>] { (void) _h.<a class="code" href="classllfio__v2__xxx_1_1handle.html#a101620e9fff0c0e8c346af0e9de58b6a">set_append_only</a>(<span class="keyword">false</span>); });</div><div class="line"><a name="l00289"></a><span class="lineno"> 289</span>  file_handle::extent_guard append_guard;</div><div class="line"><a name="l00290"></a><span class="lineno"> 290</span>  <span class="keywordflow">if</span>(_nfs_compatibility)</div><div class="line"><a name="l00291"></a><span class="lineno"> 291</span>  {</div><div class="line"><a name="l00292"></a><span class="lineno"> 292</span>  <span class="keyword">auto</span> lastbyte = <span class="keyword">static_cast<</span>file_handle::extent_type<span class="keyword">></span>(-1);</div><div class="line"><a name="l00293"></a><span class="lineno"> 293</span>  <span class="comment">// Lock up to the beginning of the shadow lock space</span></div><div class="line"><a name="l00294"></a><span class="lineno"> 294</span>  lastbyte &= ~(1ULL << 63U);</div><div class="line"><a name="l00295"></a><span class="lineno"> 295</span>  OUTCOME_TRY(append_guard_, _h.<a class="code" href="classllfio__v2__xxx_1_1io__handle.html#a29cc9f2525f78dd73f8402cb59d97212">lock</a>(my_lock_request_offset, lastbyte, <span class="keyword">true</span>));</div><div class="line"><a name="l00296"></a><span class="lineno"> 296</span>  append_guard = std::move(append_guard_);</div><div class="line"><a name="l00297"></a><span class="lineno"> 297</span>  }</div><div class="line"><a name="l00298"></a><span class="lineno"> 298</span>  OUTCOME_TRYV(_h.<a class="code" href="classllfio__v2__xxx_1_1io__handle.html#a83884eca7b4cd09125a5cf8a155e6052">write</a>(0, {{reinterpret_cast<byte *>(&lock_request), sizeof(lock_request)}}));</div><div class="line"><a name="l00299"></a><span class="lineno"> 299</span>  }</div><div class="line"><a name="l00300"></a><span class="lineno"> 300</span> </div><div class="line"><a name="l00301"></a><span class="lineno"> 301</span>  <span class="comment">// Find the record I just wrote</span></div><div class="line"><a name="l00302"></a><span class="lineno"> 302</span>  <span class="keyword">alignas</span>(64) byte _buffer[4096 + 2048]; <span class="comment">// 6Kb cache line aligned buffer</span></div><div class="line"><a name="l00303"></a><span class="lineno"> 303</span>  <span class="comment">// Read onwards from length as reported before I wrote my lock request</span></div><div class="line"><a name="l00304"></a><span class="lineno"> 304</span>  <span class="comment">// until I find my lock request. This loop should never actually iterate</span></div><div class="line"><a name="l00305"></a><span class="lineno"> 305</span>  <span class="comment">// except under extreme load conditions.</span><span class="comment"></span></div><div class="line"><a name="l00306"></a><span class="lineno"> 306</span> <span class="comment"> //! \todo Read from header.last_known_good immediately if possible in order</span></div><div class="line"><a name="l00307"></a><span class="lineno"> 307</span> <span class="comment"> //! to avoid a duplicate read later</span></div><div class="line"><a name="l00308"></a><span class="lineno"> 308</span> <span class="comment"></span> <span class="keywordflow">for</span>(;;)</div><div class="line"><a name="l00309"></a><span class="lineno"> 309</span>  {</div><div class="line"><a name="l00310"></a><span class="lineno"> 310</span>  file_handle::buffer_type req{_buffer, <span class="keyword">sizeof</span>(_buffer)};</div><div class="line"><a name="l00311"></a><span class="lineno"> 311</span>  file_handle::io_result<file_handle::buffers_type> readoutcome = _h.<a class="code" href="classllfio__v2__xxx_1_1file__handle.html#a6e46c6ea379152eb559ab15990f7c467">read</a>({req, my_lock_request_offset});</div><div class="line"><a name="l00312"></a><span class="lineno"> 312</span>  <span class="comment">// Should never happen :)</span></div><div class="line"><a name="l00313"></a><span class="lineno"> 313</span>  <span class="keywordflow">if</span>(readoutcome.has_error())</div><div class="line"><a name="l00314"></a><span class="lineno"> 314</span>  {</div><div class="line"><a name="l00315"></a><span class="lineno"> 315</span>  LLFIO_LOG_FATAL(<span class="keyword">this</span>, <span class="stringliteral">"atomic_append::lock() saw an error when searching for just written data"</span>);</div><div class="line"><a name="l00316"></a><span class="lineno"> 316</span>  std::terminate();</div><div class="line"><a name="l00317"></a><span class="lineno"> 317</span>  }</div><div class="line"><a name="l00318"></a><span class="lineno"> 318</span>  <span class="keyword">const</span> atomic_append_detail::lock_request *record, *lastrecord;</div><div class="line"><a name="l00319"></a><span class="lineno"> 319</span>  <span class="keywordflow">for</span>(record = reinterpret_cast<const atomic_append_detail::lock_request *>(readoutcome.value()[0].data()), lastrecord = reinterpret_cast<const atomic_append_detail::lock_request *>(readoutcome.value()[0].data() + readoutcome.value()[0].size()); record < lastrecord && record->hash != lock_request.hash;</div><div class="line"><a name="l00320"></a><span class="lineno"> 320</span>  ++record)</div><div class="line"><a name="l00321"></a><span class="lineno"> 321</span>  {</div><div class="line"><a name="l00322"></a><span class="lineno"> 322</span>  my_lock_request_offset += <span class="keyword">sizeof</span>(atomic_append_detail::lock_request);</div><div class="line"><a name="l00323"></a><span class="lineno"> 323</span>  }</div><div class="line"><a name="l00324"></a><span class="lineno"> 324</span>  <span class="keywordflow">if</span>(record->hash == lock_request.hash)</div><div class="line"><a name="l00325"></a><span class="lineno"> 325</span>  {</div><div class="line"><a name="l00326"></a><span class="lineno"> 326</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00327"></a><span class="lineno"> 327</span>  }</div><div class="line"><a name="l00328"></a><span class="lineno"> 328</span>  }</div><div class="line"><a name="l00329"></a><span class="lineno"> 329</span> </div><div class="line"><a name="l00330"></a><span class="lineno"> 330</span>  <span class="comment">// extent_guard is now valid and will be unlocked on error</span></div><div class="line"><a name="l00331"></a><span class="lineno"> 331</span>  out.hint = my_lock_request_offset;</div><div class="line"><a name="l00332"></a><span class="lineno"> 332</span>  disableunlock.dismiss();</div><div class="line"><a name="l00333"></a><span class="lineno"> 333</span> </div><div class="line"><a name="l00334"></a><span class="lineno"> 334</span>  <span class="comment">// Lock my request for writing so others can sleep on me</span></div><div class="line"><a name="l00335"></a><span class="lineno"> 335</span>  file_handle::extent_guard my_request_guard;</div><div class="line"><a name="l00336"></a><span class="lineno"> 336</span>  <span class="keywordflow">if</span>(!spin_not_sleep)</div><div class="line"><a name="l00337"></a><span class="lineno"> 337</span>  {</div><div class="line"><a name="l00338"></a><span class="lineno"> 338</span>  <span class="keyword">auto</span> lock_offset = my_lock_request_offset;</div><div class="line"><a name="l00339"></a><span class="lineno"> 339</span>  <span class="comment">// Set the top bit to use the shadow lock space on Windows</span></div><div class="line"><a name="l00340"></a><span class="lineno"> 340</span>  lock_offset |= (1ULL << 63U);</div><div class="line"><a name="l00341"></a><span class="lineno"> 341</span>  OUTCOME_TRY(my_request_guard_, _h.<a class="code" href="classllfio__v2__xxx_1_1io__handle.html#a29cc9f2525f78dd73f8402cb59d97212">lock</a>(lock_offset, <span class="keyword">sizeof</span>(lock_request), <span class="keyword">true</span>));</div><div class="line"><a name="l00342"></a><span class="lineno"> 342</span>  my_request_guard = std::move(my_request_guard_);</div><div class="line"><a name="l00343"></a><span class="lineno"> 343</span>  }</div><div class="line"><a name="l00344"></a><span class="lineno"> 344</span> </div><div class="line"><a name="l00345"></a><span class="lineno"> 345</span>  <span class="comment">// Read every record preceding mine until header.first_known_good inclusive</span></div><div class="line"><a name="l00346"></a><span class="lineno"> 346</span>  <span class="keyword">auto</span> record_offset = my_lock_request_offset - <span class="keyword">sizeof</span>(atomic_append_detail::lock_request);</div><div class="line"><a name="l00347"></a><span class="lineno"> 347</span>  <span class="keywordflow">do</span></div><div class="line"><a name="l00348"></a><span class="lineno"> 348</span>  {</div><div class="line"><a name="l00349"></a><span class="lineno"> 349</span>  reload:</div><div class="line"><a name="l00350"></a><span class="lineno"> 350</span>  <span class="comment">// Refresh the header and load a snapshot of everything between record_offset</span></div><div class="line"><a name="l00351"></a><span class="lineno"> 351</span>  <span class="comment">// and first_known_good or -6Kb, whichever the sooner</span></div><div class="line"><a name="l00352"></a><span class="lineno"> 352</span>  OUTCOME_TRYV(_read_header());</div><div class="line"><a name="l00353"></a><span class="lineno"> 353</span>  <span class="comment">// If there are no preceding records, we're done</span></div><div class="line"><a name="l00354"></a><span class="lineno"> 354</span>  <span class="keywordflow">if</span>(record_offset < _header.first_known_good)</div><div class="line"><a name="l00355"></a><span class="lineno"> 355</span>  {</div><div class="line"><a name="l00356"></a><span class="lineno"> 356</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00357"></a><span class="lineno"> 357</span>  }</div><div class="line"><a name="l00358"></a><span class="lineno"> 358</span>  <span class="keyword">auto</span> start_offset = record_offset;</div><div class="line"><a name="l00359"></a><span class="lineno"> 359</span>  <span class="keywordflow">if</span>(start_offset > <span class="keyword">sizeof</span>(_buffer) - <span class="keyword">sizeof</span>(atomic_append_detail::lock_request))</div><div class="line"><a name="l00360"></a><span class="lineno"> 360</span>  {</div><div class="line"><a name="l00361"></a><span class="lineno"> 361</span>  start_offset -= <span class="keyword">sizeof</span>(_buffer) - <span class="keyword">sizeof</span>(atomic_append_detail::lock_request);</div><div class="line"><a name="l00362"></a><span class="lineno"> 362</span>  }</div><div class="line"><a name="l00363"></a><span class="lineno"> 363</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00364"></a><span class="lineno"> 364</span>  {</div><div class="line"><a name="l00365"></a><span class="lineno"> 365</span>  start_offset = <span class="keyword">sizeof</span>(atomic_append_detail::lock_request);</div><div class="line"><a name="l00366"></a><span class="lineno"> 366</span>  }</div><div class="line"><a name="l00367"></a><span class="lineno"> 367</span>  <span class="keywordflow">if</span>(start_offset < _header.first_known_good)</div><div class="line"><a name="l00368"></a><span class="lineno"> 368</span>  {</div><div class="line"><a name="l00369"></a><span class="lineno"> 369</span>  start_offset = _header.first_known_good;</div><div class="line"><a name="l00370"></a><span class="lineno"> 370</span>  }</div><div class="line"><a name="l00371"></a><span class="lineno"> 371</span>  assert(record_offset >= start_offset);</div><div class="line"><a name="l00372"></a><span class="lineno"> 372</span>  assert(record_offset - start_offset <= <span class="keyword">sizeof</span>(_buffer));</div><div class="line"><a name="l00373"></a><span class="lineno"> 373</span>  file_handle::buffer_type req{_buffer, (size_t)(record_offset - start_offset) + <span class="keyword">sizeof</span>(atomic_append_detail::lock_request)};</div><div class="line"><a name="l00374"></a><span class="lineno"> 374</span>  OUTCOME_TRY(batchread, _h.<a class="code" href="classllfio__v2__xxx_1_1file__handle.html#a6e46c6ea379152eb559ab15990f7c467">read</a>({req, start_offset}));</div><div class="line"><a name="l00375"></a><span class="lineno"> 375</span>  assert(batchread[0].size() == record_offset - start_offset + <span class="keyword">sizeof</span>(atomic_append_detail::lock_request));</div><div class="line"><a name="l00376"></a><span class="lineno"> 376</span>  <span class="keyword">const</span> atomic_append_detail::lock_request *record = <span class="keyword">reinterpret_cast<</span>atomic_append_detail::lock_request *<span class="keyword">></span>(batchread[0].data() + batchread[0].size() - <span class="keyword">sizeof</span>(atomic_append_detail::lock_request));</div><div class="line"><a name="l00377"></a><span class="lineno"> 377</span>  <span class="keyword">const</span> atomic_append_detail::lock_request *firstrecord = <span class="keyword">reinterpret_cast<</span>atomic_append_detail::lock_request *<span class="keyword">></span>(batchread[0].data());</div><div class="line"><a name="l00378"></a><span class="lineno"> 378</span> </div><div class="line"><a name="l00379"></a><span class="lineno"> 379</span>  <span class="comment">// Skip all completed lock requests or not mentioning any of my entities</span></div><div class="line"><a name="l00380"></a><span class="lineno"> 380</span>  <span class="keywordflow">for</span>(; record >= firstrecord; record_offset -= <span class="keyword">sizeof</span>(atomic_append_detail::lock_request), --record)</div><div class="line"><a name="l00381"></a><span class="lineno"> 381</span>  {</div><div class="line"><a name="l00382"></a><span class="lineno"> 382</span>  <span class="comment">// If a completed lock request, skip</span></div><div class="line"><a name="l00383"></a><span class="lineno"> 383</span>  <span class="keywordflow">if</span>(!record->hash && (record->unique_id == 0u))</div><div class="line"><a name="l00384"></a><span class="lineno"> 384</span>  {</div><div class="line"><a name="l00385"></a><span class="lineno"> 385</span>  <span class="keywordflow">continue</span>;</div><div class="line"><a name="l00386"></a><span class="lineno"> 386</span>  }</div><div class="line"><a name="l00387"></a><span class="lineno"> 387</span>  <span class="comment">// If record hash doesn't match contents it's a torn read, reload</span></div><div class="line"><a name="l00388"></a><span class="lineno"> 388</span>  <span class="keywordflow">if</span>(!_skip_hashing)</div><div class="line"><a name="l00389"></a><span class="lineno"> 389</span>  {</div><div class="line"><a name="l00390"></a><span class="lineno"> 390</span>  <span class="keywordflow">if</span>(record->hash != QUICKCPPLIB_NAMESPACE::algorithm::hash::fast_hash::hash((reinterpret_cast<const char *>(record)) + 16, <span class="keyword">sizeof</span>(atomic_append_detail::lock_request) - 16))</div><div class="line"><a name="l00391"></a><span class="lineno"> 391</span>  {</div><div class="line"><a name="l00392"></a><span class="lineno"> 392</span>  <span class="keywordflow">goto</span> reload;</div><div class="line"><a name="l00393"></a><span class="lineno"> 393</span>  }</div><div class="line"><a name="l00394"></a><span class="lineno"> 394</span>  }</div><div class="line"><a name="l00395"></a><span class="lineno"> 395</span> </div><div class="line"><a name="l00396"></a><span class="lineno"> 396</span>  <span class="comment">// Does this record lock anything I am locking?</span></div><div class="line"><a name="l00397"></a><span class="lineno"> 397</span>  <span class="keywordflow">for</span>(<span class="keyword">const</span> <span class="keyword">auto</span> &entity : out.entities)</div><div class="line"><a name="l00398"></a><span class="lineno"> 398</span>  {</div><div class="line"><a name="l00399"></a><span class="lineno"> 399</span>  <span class="keywordflow">for</span>(<span class="keywordtype">size_t</span> n = 0; n < record->items; n++)</div><div class="line"><a name="l00400"></a><span class="lineno"> 400</span>  {</div><div class="line"><a name="l00401"></a><span class="lineno"> 401</span>  <span class="keywordflow">if</span>(record->entities[n].value == entity.value)</div><div class="line"><a name="l00402"></a><span class="lineno"> 402</span>  {</div><div class="line"><a name="l00403"></a><span class="lineno"> 403</span>  <span class="comment">// Is the lock I want exclusive or the lock he wants exclusive?</span></div><div class="line"><a name="l00404"></a><span class="lineno"> 404</span>  <span class="comment">// If so, need to block</span></div><div class="line"><a name="l00405"></a><span class="lineno"> 405</span>  <span class="keywordflow">if</span>((record->entities[n].exclusive != 0u) || (entity.exclusive != 0u))</div><div class="line"><a name="l00406"></a><span class="lineno"> 406</span>  {</div><div class="line"><a name="l00407"></a><span class="lineno"> 407</span>  <span class="keywordflow">goto</span> beginwait;</div><div class="line"><a name="l00408"></a><span class="lineno"> 408</span>  }</div><div class="line"><a name="l00409"></a><span class="lineno"> 409</span>  }</div><div class="line"><a name="l00410"></a><span class="lineno"> 410</span>  }</div><div class="line"><a name="l00411"></a><span class="lineno"> 411</span>  }</div><div class="line"><a name="l00412"></a><span class="lineno"> 412</span>  }</div><div class="line"><a name="l00413"></a><span class="lineno"> 413</span>  <span class="comment">// None of this batch of records has anything to do with my request, so keep going</span></div><div class="line"><a name="l00414"></a><span class="lineno"> 414</span>  <span class="keywordflow">continue</span>;</div><div class="line"><a name="l00415"></a><span class="lineno"> 415</span> </div><div class="line"><a name="l00416"></a><span class="lineno"> 416</span>  beginwait:</div><div class="line"><a name="l00417"></a><span class="lineno"> 417</span>  <span class="comment">// Sleep until this record is freed using a shared lock</span></div><div class="line"><a name="l00418"></a><span class="lineno"> 418</span>  <span class="comment">// on the record in our way. Note there is a race here</span></div><div class="line"><a name="l00419"></a><span class="lineno"> 419</span>  <span class="comment">// between when the lock requester writes the lock</span></div><div class="line"><a name="l00420"></a><span class="lineno"> 420</span>  <span class="comment">// request and when he takes an exclusive lock on it,</span></div><div class="line"><a name="l00421"></a><span class="lineno"> 421</span>  <span class="comment">// so if our shared lock succeeds we need to immediately</span></div><div class="line"><a name="l00422"></a><span class="lineno"> 422</span>  <span class="comment">// unlock and retry based on the data.</span></div><div class="line"><a name="l00423"></a><span class="lineno"> 423</span>  std::this_thread::yield();</div><div class="line"><a name="l00424"></a><span class="lineno"> 424</span>  <span class="keywordflow">if</span>(!spin_not_sleep)</div><div class="line"><a name="l00425"></a><span class="lineno"> 425</span>  {</div><div class="line"><a name="l00426"></a><span class="lineno"> 426</span>  deadline nd;</div><div class="line"><a name="l00427"></a><span class="lineno"> 427</span>  <span class="keywordflow">if</span>(d)</div><div class="line"><a name="l00428"></a><span class="lineno"> 428</span>  {</div><div class="line"><a name="l00429"></a><span class="lineno"> 429</span>  <span class="keywordflow">if</span>((d).steady)</div><div class="line"><a name="l00430"></a><span class="lineno"> 430</span>  {</div><div class="line"><a name="l00431"></a><span class="lineno"> 431</span>  std::chrono::nanoseconds ns = std::chrono::duration_cast<std::chrono::nanoseconds>((began_steady + std::chrono::nanoseconds((d).nsecs)) - std::chrono::steady_clock::now());</div><div class="line"><a name="l00432"></a><span class="lineno"> 432</span>  <span class="keywordflow">if</span>(ns.count() < 0)</div><div class="line"><a name="l00433"></a><span class="lineno"> 433</span>  {</div><div class="line"><a name="l00434"></a><span class="lineno"> 434</span>  (nd).nsecs = 0;</div><div class="line"><a name="l00435"></a><span class="lineno"> 435</span>  }</div><div class="line"><a name="l00436"></a><span class="lineno"> 436</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00437"></a><span class="lineno"> 437</span>  {</div><div class="line"><a name="l00438"></a><span class="lineno"> 438</span>  (nd).nsecs = ns.count();</div><div class="line"><a name="l00439"></a><span class="lineno"> 439</span>  }</div><div class="line"><a name="l00440"></a><span class="lineno"> 440</span>  }</div><div class="line"><a name="l00441"></a><span class="lineno"> 441</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00442"></a><span class="lineno"> 442</span>  {</div><div class="line"><a name="l00443"></a><span class="lineno"> 443</span>  (nd) = (d);</div><div class="line"><a name="l00444"></a><span class="lineno"> 444</span>  }</div><div class="line"><a name="l00445"></a><span class="lineno"> 445</span>  }</div><div class="line"><a name="l00446"></a><span class="lineno"> 446</span>  <span class="keyword">auto</span> lock_offset = record_offset;</div><div class="line"><a name="l00447"></a><span class="lineno"> 447</span>  <span class="comment">// Set the top bit to use the shadow lock space on Windows</span></div><div class="line"><a name="l00448"></a><span class="lineno"> 448</span>  lock_offset |= (1ULL << 63U);</div><div class="line"><a name="l00449"></a><span class="lineno"> 449</span>  OUTCOME_TRYV(_h.<a class="code" href="classllfio__v2__xxx_1_1io__handle.html#a29cc9f2525f78dd73f8402cb59d97212">lock</a>(lock_offset, <span class="keyword">sizeof</span>(*record), <span class="keyword">false</span>, nd));</div><div class="line"><a name="l00450"></a><span class="lineno"> 450</span>  }</div><div class="line"><a name="l00451"></a><span class="lineno"> 451</span>  <span class="comment">// Make sure we haven't timed out during this wait</span></div><div class="line"><a name="l00452"></a><span class="lineno"> 452</span>  <span class="keywordflow">if</span>(d)</div><div class="line"><a name="l00453"></a><span class="lineno"> 453</span>  {</div><div class="line"><a name="l00454"></a><span class="lineno"> 454</span>  <span class="keywordflow">if</span>((d).steady)</div><div class="line"><a name="l00455"></a><span class="lineno"> 455</span>  {</div><div class="line"><a name="l00456"></a><span class="lineno"> 456</span>  <span class="keywordflow">if</span>(std::chrono::steady_clock::now() >= (began_steady + std::chrono::nanoseconds((d).nsecs)))</div><div class="line"><a name="l00457"></a><span class="lineno"> 457</span>  {</div><div class="line"><a name="l00458"></a><span class="lineno"> 458</span>  <span class="keywordflow">return</span> errc::timed_out;</div><div class="line"><a name="l00459"></a><span class="lineno"> 459</span>  }</div><div class="line"><a name="l00460"></a><span class="lineno"> 460</span>  }</div><div class="line"><a name="l00461"></a><span class="lineno"> 461</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00462"></a><span class="lineno"> 462</span>  {</div><div class="line"><a name="l00463"></a><span class="lineno"> 463</span>  <span class="keywordflow">if</span>(std::chrono::system_clock::now() >= end_utc)</div><div class="line"><a name="l00464"></a><span class="lineno"> 464</span>  {</div><div class="line"><a name="l00465"></a><span class="lineno"> 465</span>  <span class="keywordflow">return</span> errc::timed_out;</div><div class="line"><a name="l00466"></a><span class="lineno"> 466</span>  }</div><div class="line"><a name="l00467"></a><span class="lineno"> 467</span>  }</div><div class="line"><a name="l00468"></a><span class="lineno"> 468</span>  }</div><div class="line"><a name="l00469"></a><span class="lineno"> 469</span>  } <span class="keywordflow">while</span>(record_offset >= _header.first_known_good);</div><div class="line"><a name="l00470"></a><span class="lineno"> 470</span>  <span class="keywordflow">return</span> success();</div><div class="line"><a name="l00471"></a><span class="lineno"> 471</span>  }</div><div class="ttc" id="classllfio__v2__xxx_1_1io__handle_html_a83884eca7b4cd09125a5cf8a155e6052"><div class="ttname"><a href="classllfio__v2__xxx_1_1io__handle.html#a83884eca7b4cd09125a5cf8a155e6052">llfio_v2_xxx::io_handle::write</a></div><div class="ttdeci">virtual io_result< const_buffers_type > write(io_request< const_buffers_type > reqs, deadline d=deadline()) noexcept</div><div class="ttdoc">Write data to the open handle. </div></div> @@ -315,7 +315,7 @@ Protected Member Functions</h2></td></tr> </table> </dd> </dl> -<dl class="todo"><dt><b><a class="el" href="todo.html#_todo000008">Todo:</a></b></dt><dd>fs_mutex_append needs to check if file still exists after lock is granted, awaiting path fetching. </dd></dl> +<dl class="todo"><dt><b><a class="el" href="todo.html#_todo000007">Todo:</a></b></dt><dd>fs_mutex_append needs to check if file still exists after lock is granted, awaiting path fetching. </dd></dl> <div class="fragment"><div class="line"><a name="l00204"></a><span class="lineno"> 204</span>  {</div><div class="line"><a name="l00205"></a><span class="lineno"> 205</span>  LLFIO_LOG_FUNCTION_CALL(0);</div><div class="line"><a name="l00206"></a><span class="lineno"> 206</span>  OUTCOME_TRY(ret, <a class="code" href="classllfio__v2__xxx_1_1file__handle.html#a09e6b3e9806b328a687a55e955b885a3">file_handle::file</a>(base, lockfile, <a class="code" href="classllfio__v2__xxx_1_1handle.html#aa3930273a2d4cabbac309e0b75701dcaaefb2a684e4afb7d55e6147fbe5a332ee">file_handle::mode::write</a>, <a class="code" href="classllfio__v2__xxx_1_1handle.html#af0b352d0f273ba6fa70c178b2c2fee42a8f0339e854eb5321306a443ce9199e1d">file_handle::creation::if_needed</a>, <a class="code" href="classllfio__v2__xxx_1_1handle.html#aecd3a7db6cee3aec07d32fe6f99e6852ad5197d93c063a2b1e22d1630a39b7aef">file_handle::caching::temporary</a>));</div><div class="line"><a name="l00207"></a><span class="lineno"> 207</span>  atomic_append_detail::header header;</div><div class="line"><a name="l00208"></a><span class="lineno"> 208</span>  <span class="comment">// Lock the entire header for exclusive access</span></div><div class="line"><a name="l00209"></a><span class="lineno"> 209</span>  <span class="keyword">auto</span> lockresult = ret.try_lock(0, <span class="keyword">sizeof</span>(header), <span class="keyword">true</span>);<span class="comment"></span></div><div class="line"><a name="l00210"></a><span class="lineno"> 210</span> <span class="comment"> //! \todo fs_mutex_append needs to check if file still exists after lock is granted, awaiting path fetching.</span></div><div class="line"><a name="l00211"></a><span class="lineno"> 211</span> <span class="comment"></span> <span class="keywordflow">if</span>(lockresult.has_error())</div><div class="line"><a name="l00212"></a><span class="lineno"> 212</span>  {</div><div class="line"><a name="l00213"></a><span class="lineno"> 213</span>  <span class="keywordflow">if</span>(lockresult.error() != errc::timed_out)</div><div class="line"><a name="l00214"></a><span class="lineno"> 214</span>  {</div><div class="line"><a name="l00215"></a><span class="lineno"> 215</span>  <span class="keywordflow">return</span> std::move(lockresult).error();</div><div class="line"><a name="l00216"></a><span class="lineno"> 216</span>  }</div><div class="line"><a name="l00217"></a><span class="lineno"> 217</span>  <span class="comment">// Somebody else is also using this file</span></div><div class="line"><a name="l00218"></a><span class="lineno"> 218</span>  }</div><div class="line"><a name="l00219"></a><span class="lineno"> 219</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00220"></a><span class="lineno"> 220</span>  {</div><div class="line"><a name="l00221"></a><span class="lineno"> 221</span>  <span class="comment">// I am the first person to be using this (stale?) file, so write a new header and truncate</span></div><div class="line"><a name="l00222"></a><span class="lineno"> 222</span>  OUTCOME_TRYV(ret.truncate(<span class="keyword">sizeof</span>(header)));</div><div class="line"><a name="l00223"></a><span class="lineno"> 223</span>  memset(&header, 0, <span class="keyword">sizeof</span>(header));</div><div class="line"><a name="l00224"></a><span class="lineno"> 224</span>  header.time_offset = std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());</div><div class="line"><a name="l00225"></a><span class="lineno"> 225</span>  header.first_known_good = <span class="keyword">sizeof</span>(header);</div><div class="line"><a name="l00226"></a><span class="lineno"> 226</span>  header.first_after_hole_punch = <span class="keyword">sizeof</span>(header);</div><div class="line"><a name="l00227"></a><span class="lineno"> 227</span>  <span class="keywordflow">if</span>(!skip_hashing)</div><div class="line"><a name="l00228"></a><span class="lineno"> 228</span>  {</div><div class="line"><a name="l00229"></a><span class="lineno"> 229</span>  header.hash = QUICKCPPLIB_NAMESPACE::algorithm::hash::fast_hash::hash((reinterpret_cast<char *>(&header)) + 16, <span class="keyword">sizeof</span>(header) - 16);</div><div class="line"><a name="l00230"></a><span class="lineno"> 230</span>  }</div><div class="line"><a name="l00231"></a><span class="lineno"> 231</span>  OUTCOME_TRYV(ret.write(0, {{reinterpret_cast<byte *>(&header), sizeof(header)}}));</div><div class="line"><a name="l00232"></a><span class="lineno"> 232</span>  }</div><div class="line"><a name="l00233"></a><span class="lineno"> 233</span>  <span class="comment">// Open a shared lock on last byte in header to prevent other users zomping the file</span></div><div class="line"><a name="l00234"></a><span class="lineno"> 234</span>  OUTCOME_TRY(guard, ret.lock(<span class="keyword">sizeof</span>(header) - 1, 1, <span class="keyword">false</span>));</div><div class="line"><a name="l00235"></a><span class="lineno"> 235</span>  <span class="comment">// Unlock any exclusive lock I gained earlier now</span></div><div class="line"><a name="l00236"></a><span class="lineno"> 236</span>  <span class="keywordflow">if</span>(lockresult)</div><div class="line"><a name="l00237"></a><span class="lineno"> 237</span>  {</div><div class="line"><a name="l00238"></a><span class="lineno"> 238</span>  lockresult.value().unlock();</div><div class="line"><a name="l00239"></a><span class="lineno"> 239</span>  }</div><div class="line"><a name="l00240"></a><span class="lineno"> 240</span>  <span class="comment">// The constructor will read and cache the header</span></div><div class="line"><a name="l00241"></a><span class="lineno"> 241</span>  <span class="keywordflow">return</span> atomic_append(std::move(ret), std::move(guard), nfs_compatibility, skip_hashing);</div><div class="line"><a name="l00242"></a><span class="lineno"> 242</span>  }</div><div class="ttc" id="classllfio__v2__xxx_1_1file__handle_html_a09e6b3e9806b328a687a55e955b885a3"><div class="ttname"><a href="classllfio__v2__xxx_1_1file__handle.html#a09e6b3e9806b328a687a55e955b885a3">llfio_v2_xxx::file_handle::file</a></div><div class="ttdeci">static result< file_handle > file(const path_handle &base, path_view_type path, mode _mode=mode::read, creation _creation=creation::open_existing, caching _caching=caching::all, flag flags=flag::none) noexcept</div></div> <div class="ttc" id="classllfio__v2__xxx_1_1handle_html_aa3930273a2d4cabbac309e0b75701dcaaefb2a684e4afb7d55e6147fbe5a332ee"><div class="ttname"><a href="classllfio__v2__xxx_1_1handle.html#aa3930273a2d4cabbac309e0b75701dcaaefb2a684e4afb7d55e6147fbe5a332ee">llfio_v2_xxx::handle::mode::write</a></div><div class="ttdoc">Ability to read and write (READ_CONTROL|FILE_READ_DATA|FILE_READ_ATTRIBUTES|FILE_READ_EA|FILE_WRITE_D...</div></div> <div class="ttc" id="classllfio__v2__xxx_1_1handle_html_aecd3a7db6cee3aec07d32fe6f99e6852ad5197d93c063a2b1e22d1630a39b7aef"><div class="ttname"><a href="classllfio__v2__xxx_1_1handle.html#aecd3a7db6cee3aec07d32fe6f99e6852ad5197d93c063a2b1e22d1630a39b7aef">llfio_v2_xxx::handle::caching::temporary</a></div><div class="ttdoc">Cache reads and writes of data and metadata so they complete immediately, only sending any updates to...</div></div> |