package procfs // While implementing parsing of /proc/[pid]/mountstats, this blog was used // heavily as a reference: // https://utcc.utoronto.ca/~cks/space/blog/linux/NFSMountstatsIndex // // Special thanks to Chris Siebenmann for all of his posts explaining the // various statistics available for NFS. import ( "bufio" "fmt" "io" "strconv" "strings" "time" ) // Constants shared between multiple functions. const ( deviceEntryLen = 8 fieldBytesLen = 8 fieldEventsLen = 27 statVersion10 = "1.0" statVersion11 = "1.1" fieldTransport10Len = 10 fieldTransport11Len = 13 ) // A Mount is a device mount parsed from /proc/[pid]/mountstats. type Mount struct { // Name of the device. Device string // The mount point of the device. Mount string // The filesystem type used by the device. Type string // If available additional statistics related to this Mount. // Use a type assertion to determine if additional statistics are available. Stats MountStats } // A MountStats is a type which contains detailed statistics for a specific // type of Mount. type MountStats interface { mountStats() } // A MountStatsNFS is a MountStats implementation for NFSv3 and v4 mounts. type MountStatsNFS struct { // The version of statistics provided. StatVersion string // The age of the NFS mount. Age time.Duration // Statistics related to byte counters for various operations. Bytes NFSBytesStats // Statistics related to various NFS event occurrences. Events NFSEventsStats // Statistics broken down by filesystem operation. Operations []NFSOperationStats // Statistics about the NFS RPC transport. Transport NFSTransportStats } // mountStats implements MountStats. func (m MountStatsNFS) mountStats() {} // A NFSBytesStats contains statistics about the number of bytes read and written // by an NFS client to and from an NFS server. type NFSBytesStats struct { // Number of bytes read using the read() syscall. Read uint64 // Number of bytes written using the write() syscall. Write uint64 // Number of bytes read using the read() syscall in O_DIRECT mode. DirectRead uint64 // Number of bytes written using the write() syscall in O_DIRECT mode. DirectWrite uint64 // Number of bytes read from the NFS server, in total. ReadTotal uint64 // Number of bytes written to the NFS server, in total. WriteTotal uint64 // Number of pages read directly via mmap()'d files. ReadPages uint64 // Number of pages written directly via mmap()'d files. WritePages uint64 } // A NFSEventsStats contains statistics about NFS event occurrences. type NFSEventsStats struct { // Number of times cached inode attributes are re-validated from the server. InodeRevalidate uint64 // Number of times cached dentry nodes are re-validated from the server. DnodeRevalidate uint64 // Number of times an inode cache is cleared. DataInvalidate uint64 // Number of times cached inode attributes are invalidated. AttributeInvalidate uint64 // Number of times files or directories have been open()'d. VFSOpen uint64 // Number of times a directory lookup has occurred. VFSLookup uint64 // Number of times permissions have been checked. VFSAccess uint64 // Number of updates (and potential writes) to pages. VFSUpdatePage uint64 // Number of pages read directly via mmap()'d files. VFSReadPage uint64 // Number of times a group of pages have been read. VFSReadPages uint64 // Number of pages written directly via mmap()'d files. VFSWritePage uint64 // Number of times a group of pages have been written. VFSWritePages uint64 // Number of times directory entries have been read with getdents(). VFSGetdents uint64 // Number of times attributes have been set on inodes. VFSSetattr uint64 // Number of pending writes that have been forcefully flushed to the server. VFSFlush uint64 // Number of times fsync() has been called on directories and files. VFSFsync uint64 // Number of times locking has been attempted on a file. VFSLock uint64 // Number of times files have been closed and released. VFSFileRelease uint64 // Unknown. Possibly unused. CongestionWait uint64 // Number of times files have been truncated. Truncation uint64 // Number of times a file has been grown due to writes beyond its existing end. WriteExtension uint64 // Number of times a file was removed while still open by another process. SillyRename uint64 // Number of times the NFS server gave less data than expected while reading. ShortRead uint64 // Number of times the NFS server wrote less data than expected while writing. ShortWrite uint64 // Number of times the NFS server indicated EJUKEBOX; retrieving data from // offline storage. JukeboxDelay uint64 // Number of NFS v4.1+ pNFS reads. PNFSRead uint64 // Number of NFS v4.1+ pNFS writes. PNFSWrite uint64 } // A NFSOperationStats contains statistics for a single operation. type NFSOperationStats struct { // The name of the operation. Operation string // Number of requests performed for this operation. Requests uint64 // Number of times an actual RPC request has been transmitted for this operation. Transmissions uint64 // Number of times a request has had a major timeout. MajorTimeouts uint64 // Number of bytes sent for this operation, including RPC headers and payload. BytesSent uint64 // Number of bytes received for this operation, including RPC headers and payload. BytesReceived uint64 // Duration all requests spent queued for transmission before they were sent. CumulativeQueueTime time.Duration // Duration it took to get a reply back after the request was transmitted. CumulativeTotalResponseTime time.Duration // Duration from when a request was enqueued to when it was completely handled. CumulativeTotalRequestTime time.Duration } // A NFSTransportStats contains statistics for the NFS mount RPC requests and // responses. type NFSTransportStats struct { // The local port used for the NFS mount. Port uint64 // Number of times the client has had to establish a connection from scratch // to the NFS server. Bind uint64 // Number of times the client has made a TCP connection to the NFS server. Connect uint64 // Duration (in jiffies, a kernel internal unit of time) the NFS mount has // spent waiting for connections to the server to be established. ConnectIdleTime uint64 // Duration since the NFS mount last saw any RPC traffic. IdleTime time.Duration // Number of RPC requests for this mount sent to the NFS server. Sends uint64 // Number of RPC responses for this mount received from the NFS server. Receives uint64 // Number of times the NFS server sent a response with a transaction ID // unknown to this client. BadTransactionIDs uint64 // A running counter, incremented on each request as the current difference // ebetween sends and receives. CumulativeActiveRequests uint64 // A running counter, incremented on each request by the current backlog // queue size. CumulativeBacklog uint64 // Stats below only available with stat version 1.1. // Maximum number of simultaneously active RPC requests ever used. MaximumRPCSlotsUsed uint64 // A running counter, incremented on each request as the current size of the // sending queue. CumulativeSendingQueue uint64 // A running counter, incremented on each request as the current size of the // pending queue. CumulativePendingQueue uint64 } // parseMountStats parses a /proc/[pid]/mountstats file and returns a slice // of Mount structures containing detailed information about each mount. // If available, statistics for each mount are parsed as well. func parseMountStats(r io.Reader) ([]*Mount, error) { const ( device = "device" statVersionPrefix = "statvers=" nfs3Type = "nfs" nfs4Type = "nfs4" ) var mounts []*Mount s := bufio.NewScanner(r) for s.Scan() { // Only look for device entries in this function ss := strings.Fields(string(s.Bytes())) if len(ss) == 0 || ss[0] != device { continue } m, err := parseMount(ss) if err != nil { return nil, err } // Does this mount also possess statistics information? if len(ss) > deviceEntryLen { // Only NFSv3 and v4 are supported for parsing statistics if m.Type != nfs3Type && m.Type != nfs4Type { return nil, fmt.Errorf("cannot parse MountStats for fstype %q", m.Type) } statVersion := strings.TrimPrefix(ss[8], statVersionPrefix) stats, err := parseMountStatsNFS(s, statVersion) if err != nil { return nil, err } m.Stats = stats } mounts = append(mounts, m) } return mounts, s.Err() } // parseMount parses an entry in /proc/[pid]/mountstats in the format: // device [device] mounted on [mount] with fstype [type] func parseMount(ss []string) (*Mount, error) { if len(ss) < deviceEntryLen { return nil, fmt.Errorf("invalid device entry: %v", ss) } // Check for specific words appearing at specific indices to ensure // the format is consistent with what we expect format := []struct { i int s string }{ {i: 0, s: "device"}, {i: 2, s: "mounted"}, {i: 3, s: "on"}, {i: 5, s: "with"}, {i: 6, s: "fstype"}, } for _, f := range format { if ss[f.i] != f.s { return nil, fmt.Errorf("invalid device entry: %v", ss) } } return &Mount{ Device: ss[1], Mount: ss[4], Type: ss[7], }, nil } // parseMountStatsNFS parses a MountStatsNFS by scanning additional information // related to NFS statistics. func parseMountStatsNFS(s *bufio.Scanner, statVersion string) (*MountStatsNFS, error) { // Field indicators for parsing specific types of data const ( fieldAge = "age:" fieldBytes = "bytes:" fieldEvents = "events:" fieldPerOpStats = "per-op" fieldTransport = "xprt:" ) stats := &MountStatsNFS{ StatVersion: statVersion, } for s.Scan() { ss := strings.Fields(string(s.Bytes())) if len(ss) == 0 { break } if len(ss) < 2 { return nil, fmt.Errorf("not enough information for NFS stats: %v", ss) } switch ss[0] { case fieldAge: // Age integer is in seconds d, err := time.ParseDuration(ss[1] + "s") if err != nil { return nil, err } stats.Age = d case fieldBytes: bstats, err := parseNFSBytesStats(ss[1:]) if err != nil { return nil, err } stats.Bytes = *bstats case fieldEvents: estats, err := parseNFSEventsStats(ss[1:]) if err != nil { return nil, err } stats.Events = *estats case fieldTransport: if len(ss) < 3 { return nil, fmt.Errorf("not enough information for NFS transport stats: %v", ss) } tstats, err := parseNFSTransportStats(ss[2:], statVersion) if err != nil { return nil, err } stats.Transport = *tstats } // When encountering "per-operation statistics", we must break this // loop and parse them separately to ensure we can terminate parsing // before reaching another device entry; hence why this 'if' statement // is not just another switch case if ss[0] == fieldPerOpStats { break } } if err := s.Err(); err != nil { return nil, err } // NFS per-operation stats appear last before the next device entry perOpStats, err := parseNFSOperationStats(s) if err != nil { return nil, err } stats.Operations = perOpStats return stats, nil } // parseNFSBytesStats parses a NFSBytesStats line using an input set of // integer fields. func parseNFSBytesStats(ss []string) (*NFSBytesStats, error) { if len(ss) != fieldBytesLen { return nil, fmt.Errorf("invalid NFS bytes stats: %v", ss) } ns := make([]uint64, 0, fieldBytesLen) for _, s := range ss { n, err := strconv.ParseUint(s, 10, 64) if err != nil { return nil, err } ns = append(ns, n) } return &NFSBytesStats{ Read: ns[0], Write: ns[1], DirectRead: ns[2], DirectWrite: ns[3], ReadTotal: ns[4], WriteTotal: ns[5], ReadPages: ns[6], WritePages: ns[7], }, nil } // parseNFSEventsStats parses a NFSEventsStats line using an input set of // integer fields. func parseNFSEventsStats(ss []string) (*NFSEventsStats, error) { if len(ss) != fieldEventsLen { return nil, fmt.Errorf("invalid NFS events stats: %v", ss) } ns := make([]uint64, 0, fieldEventsLen) for _, s := range ss { n, err := strconv.ParseUint(s, 10, 64) if err != nil { return nil, err } ns = append(ns, n) } return &NFSEventsStats{ InodeRevalidate: ns[0], DnodeRevalidate: ns[1], DataInvalidate: ns[2], AttributeInvalidate: ns[3], VFSOpen: ns[4], VFSLookup: ns[5], VFSAccess: ns[6], VFSUpdatePage: ns[7], VFSReadPage: ns[8], VFSReadPages: ns[9], VFSWritePage: ns[10], VFSWritePages: ns[11], VFSGetdents: ns[12], VFSSetattr: ns[13], VFSFlush: ns[14], VFSFsync: ns[15], VFSLock: ns[16], VFSFileRelease: ns[17], CongestionWait: ns[18], Truncation: ns[19], WriteExtension: ns[20], SillyRename: ns[21], ShortRead: ns[22], ShortWrite: ns[23], JukeboxDelay: ns[24], PNFSRead: ns[25], PNFSWrite: ns[26], }, nil } // parseNFSOperationStats parses a slice of NFSOperationStats by scanning // additional information about per-operation statistics until an empty // line is reached. func parseNFSOperationStats(s *bufio.Scanner) ([]NFSOperationStats, error) { const ( // Number of expected fields in each per-operation statistics set numFields = 9 ) var ops []NFSOperationStats for s.Scan() { ss := strings.Fields(string(s.Bytes())) if len(ss) == 0 { // Must break when reading a blank line after per-operation stats to // enable top-level function to parse the next device entry break } if len(ss) != numFields { return nil, fmt.Errorf("invalid NFS per-operations stats: %v", ss) } // Skip string operation name for integers ns := make([]uint64, 0, numFields-1) for _, st := range ss[1:] { n, err := strconv.ParseUint(st, 10, 64) if err != nil { return nil, err } ns = append(ns, n) } ops = append(ops, NFSOperationStats{ Operation: strings.TrimSuffix(ss[0], ":"), Requests: ns[0], Transmissions: ns[1], MajorTimeouts: ns[2], BytesSent: ns[3], BytesReceived: ns[4], CumulativeQueueTime: time.Duration(ns[5]) * time.Millisecond, CumulativeTotalResponseTime: time.Duration(ns[6]) * time.Millisecond, CumulativeTotalRequestTime: time.Duration(ns[7]) * time.Millisecond, }) } return ops, s.Err() } // parseNFSTransportStats parses a NFSTransportStats line using an input set of // integer fields matched to a specific stats version. func parseNFSTransportStats(ss []string, statVersion string) (*NFSTransportStats, error) { switch statVersion { case statVersion10: if len(ss) != fieldTransport10Len { return nil, fmt.Errorf("invalid NFS transport stats 1.0 statement: %v", ss) } case statVersion11: if len(ss) != fieldTransport11Len { return nil, fmt.Errorf("invalid NFS transport stats 1.1 statement: %v", ss) } default: return nil, fmt.Errorf("unrecognized NFS transport stats version: %q", statVersion) } // Allocate enough for v1.1 stats since zero value for v1.1 stats will be okay // in a v1.0 response ns := make([]uint64, 0, fieldTransport11Len) for _, s := range ss { n, err := strconv.ParseUint(s, 10, 64) if err != nil { return nil, err } ns = append(ns, n) } return &NFSTransportStats{ Port: ns[0], Bind: ns[1], Connect: ns[2], ConnectIdleTime: ns[3], IdleTime: time.Duration(ns[4]) * time.Second, Sends: ns[5], Receives: ns[6], BadTransactionIDs: ns[7], CumulativeActiveRequests: ns[8], CumulativeBacklog: ns[9], MaximumRPCSlotsUsed: ns[10], CumulativeSendingQueue: ns[11], CumulativePendingQueue: ns[12], }, nil }