Function readPhysicalBlock

fdbserver/VersionedBTree.actor.cpp:2967–2977

	void freeExtent(LogicalPageID pageID) override { freeExtent_impl(this, pageID); }

	ACTOR static UNCANCELLABLE Future<int> readPhysicalBlock(DWALPager* self,
	                                                         Reference<ArenaPage> pageBuffer,
	                                                         int pageOffset,
	                                                         int blockSize,
	                                                         int64_t offset,
	                                                         int priority) {
		state PriorityMultiLock::Lock lock = wait(self->ioLock.lock(std::min(priority, ioMaxPriority)));
		++g_redwoodMetrics.metric.pagerDiskRead;
		int bytes = wait(self->pageFile->read(pageBuffer->rawData() + pageOffset, blockSize, offset));
		return bytes;
	}

	// Read a physical page from the page file.  Note that header pages use a page size of smallestPhysicalBlock.
	// If the user chosen physical page size is larger, then there will be a gap of unused space after the header pages