init bcachefs support

bcachefs/bcachefs.go

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+// Copyright 2017 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package bcachefs provides access to statistics exposed by bcachefs.
+package bcachefs
+
+// Stats contains bcachefs runtime statistics, parsed from /sys/fs/bcachefs/.
+//
+// The names and meanings of each statistic were taken from bcache.txt and
+// files in drivers/md/bcache in the Linux kernel source. Counters are uint64
+// (in-kernel counters are mostly unsigned long).
+type Stats struct {
+	// The name of the bcachefs used to source these statistics.
+	Name     string
+	Bcachefs BcachefsStats
+	Bdevs    []BdevStats
+	Caches   []CacheStats
+}
+
+// BcachefsStats contains statistics tied to a bcache ID.
+type BcachefsStats struct { // nolint:revive
+	AverageKeySize        uint64
+	BtreeCacheSize        uint64
+	CacheAvailablePercent uint64
+	Congested             uint64
+	RootUsagePercent      uint64
+	TreeDepth             uint64
+	Internal              InternalStats
+	FiveMin               PeriodStats
+	Total                 PeriodStats
+}
+
+// BdevStats contains statistics for one backing device.
+type BdevStats struct {
+	Name               string
+	DirtyData          uint64
+	FiveMin            PeriodStats
+	Total              PeriodStats
+	WritebackRateDebug WritebackRateDebugStats
+}
+
+// CacheStats contains statistics for one cache device.
+type CacheStats struct {
+	Name            string
+	IOErrors        uint64
+	MetadataWritten uint64
+	Written         uint64
+	Priority        PriorityStats
+}
+
+// PriorityStats contains statistics from the priority_stats file.
+type PriorityStats struct {
+	UnusedPercent   uint64
+	MetadataPercent uint64
+}
+
+// InternalStats contains internal bcache statistics.
+type InternalStats struct {
+	ActiveJournalEntries                uint64
+	BtreeNodes                          uint64
+	BtreeReadAverageDurationNanoSeconds uint64
+	CacheReadRaces                      uint64
+}
+
+// PeriodStats contains statistics for a time period (5 min or total).
+type PeriodStats struct {
+	Bypassed            uint64
+	CacheBypassHits     uint64
+	CacheBypassMisses   uint64
+	CacheHits           uint64
+	CacheMissCollisions uint64
+	CacheMisses         uint64
+	CacheReadaheads     uint64
+}
+
+// WritebackRateDebugStats contains bcache writeback statistics.
+type WritebackRateDebugStats struct {
+	Rate         uint64
+	Dirty        uint64
+	Target       uint64
+	Proportional int64
+	Integral     int64
+	Change       int64
+	NextIO       int64
+}