forked from etcd-io/etcd
/
mdstat.go
158 lines (128 loc) · 4.43 KB
/
mdstat.go
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package procfs
import (
"fmt"
"io/ioutil"
"path"
"regexp"
"strconv"
"strings"
)
var (
statuslineRE = regexp.MustCompile(`(\d+) blocks .*\[(\d+)/(\d+)\] \[[U_]+\]`)
buildlineRE = regexp.MustCompile(`\((\d+)/\d+\)`)
)
// MDStat holds info parsed from /proc/mdstat.
type MDStat struct {
// Name of the device.
Name string
// activity-state of the device.
ActivityState string
// Number of active disks.
DisksActive int64
// Total number of disks the device consists of.
DisksTotal int64
// Number of blocks the device holds.
BlocksTotal int64
// Number of blocks on the device that are in sync.
BlocksSynced int64
}
// ParseMDStat parses an mdstat-file and returns a struct with the relevant infos.
func (fs FS) ParseMDStat() (mdstates []MDStat, err error) {
mdStatusFilePath := path.Join(string(fs), "mdstat")
content, err := ioutil.ReadFile(mdStatusFilePath)
if err != nil {
return []MDStat{}, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
}
mdStatusFile := string(content)
lines := strings.Split(mdStatusFile, "\n")
var currentMD string
// Each md has at least the deviceline, statusline and one empty line afterwards
// so we will have probably something of the order len(lines)/3 devices
// so we use that for preallocation.
estimateMDs := len(lines) / 3
mdStates := make([]MDStat, 0, estimateMDs)
for i, l := range lines {
if l == "" {
// Skip entirely empty lines.
continue
}
if l[0] == ' ' {
// Those lines are not the beginning of a md-section.
continue
}
if strings.HasPrefix(l, "Personalities") || strings.HasPrefix(l, "unused") {
// We aren't interested in lines with general info.
continue
}
mainLine := strings.Split(l, " ")
if len(mainLine) < 3 {
return mdStates, fmt.Errorf("error parsing mdline: %s", l)
}
currentMD = mainLine[0] // name of md-device
activityState := mainLine[2] // activity status of said md-device
if len(lines) <= i+3 {
return mdStates, fmt.Errorf("error parsing %s: entry for %s has fewer lines than expected", mdStatusFilePath, currentMD)
}
active, total, size, err := evalStatusline(lines[i+1]) // parse statusline, always present
if err != nil {
return mdStates, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
}
//
// Now get the number of synced blocks.
//
// Get the line number of the syncing-line.
var j int
if strings.Contains(lines[i+2], "bitmap") { // then skip the bitmap line
j = i + 3
} else {
j = i + 2
}
// If device is syncing at the moment, get the number of currently synced bytes,
// otherwise that number equals the size of the device.
syncedBlocks := size
if strings.Contains(lines[j], "recovery") || strings.Contains(lines[j], "resync") {
syncedBlocks, err = evalBuildline(lines[j])
if err != nil {
return mdStates, fmt.Errorf("error parsing %s: %s", mdStatusFilePath, err)
}
}
mdStates = append(mdStates, MDStat{currentMD, activityState, active, total, size, syncedBlocks})
}
return mdStates, nil
}
func evalStatusline(statusline string) (active, total, size int64, err error) {
matches := statuslineRE.FindStringSubmatch(statusline)
// +1 to make it more obvious that the whole string containing the info is also returned as matches[0].
if len(matches) != 3+1 {
return 0, 0, 0, fmt.Errorf("unexpected number matches found in statusline: %s", statusline)
}
size, err = strconv.ParseInt(matches[1], 10, 64)
if err != nil {
return 0, 0, 0, fmt.Errorf("%s in statusline: %s", err, statusline)
}
total, err = strconv.ParseInt(matches[2], 10, 64)
if err != nil {
return 0, 0, 0, fmt.Errorf("%s in statusline: %s", err, statusline)
}
active, err = strconv.ParseInt(matches[3], 10, 64)
if err != nil {
return 0, 0, 0, fmt.Errorf("%s in statusline: %s", err, statusline)
}
return active, total, size, nil
}
// Gets the size that has already been synced out of the sync-line.
func evalBuildline(buildline string) (int64, error) {
matches := buildlineRE.FindStringSubmatch(buildline)
// +1 to make it more obvious that the whole string containing the info is also returned as matches[0].
if len(matches) < 1+1 {
return 0, fmt.Errorf("too few matches found in buildline: %s", buildline)
}
if len(matches) > 1+1 {
return 0, fmt.Errorf("too many matches found in buildline: %s", buildline)
}
syncedSize, err := strconv.ParseInt(matches[1], 10, 64)
if err != nil {
return 0, fmt.Errorf("%s in buildline: %s", err, buildline)
}
return syncedSize, nil
}