-// A UnixVolume is a Volume backed by a locally mounted disk.
-//
package main
import (
+ "bufio"
+ "context"
+ "flag"
"fmt"
+ "io"
"io/ioutil"
"log"
"os"
"path/filepath"
+ "regexp"
"strconv"
"strings"
+ "sync"
"syscall"
"time"
)
-// IORequests are encapsulated Get or Put requests. They are used to
-// implement serialized I/O (i.e. only one read/write operation per
-// volume). When running in serialized mode, the Keep front end sends
-// IORequests on a channel to an IORunner, which handles them one at a
-// time and returns an IOResponse.
-//
-type IOMethod int
-
-const (
- KeepGet IOMethod = iota
- KeepPut
-)
+type unixVolumeAdder struct {
+ *Config
+}
-type IORequest struct {
- method IOMethod
- loc string
- data []byte
- reply chan *IOResponse
+// String implements flag.Value
+func (s *unixVolumeAdder) String() string {
+ return "-"
}
-type IOResponse struct {
- data []byte
- err error
+func (vs *unixVolumeAdder) Set(path string) error {
+ if dirs := strings.Split(path, ","); len(dirs) > 1 {
+ log.Print("DEPRECATED: using comma-separated volume list.")
+ for _, dir := range dirs {
+ if err := vs.Set(dir); err != nil {
+ return err
+ }
+ }
+ return nil
+ }
+ vs.Config.Volumes = append(vs.Config.Volumes, &UnixVolume{
+ Root: path,
+ ReadOnly: deprecated.flagReadonly,
+ Serialize: deprecated.flagSerializeIO,
+ })
+ return nil
}
-// A UnixVolume has the following properties:
-//
-// root
-// the path to the volume's root directory
-// queue
-// A channel of IORequests. If non-nil, all I/O requests for
-// this volume should be queued on this channel; the result
-// will be delivered on the IOResponse channel supplied in the
-// request.
-//
-type UnixVolume struct {
- root string // path to this volume
- queue chan *IORequest
- readonly bool
+func init() {
+ VolumeTypes = append(VolumeTypes, func() VolumeWithExamples { return &UnixVolume{} })
+
+ flag.Var(&unixVolumeAdder{theConfig}, "volumes", "see Volumes configuration")
+ flag.Var(&unixVolumeAdder{theConfig}, "volume", "see Volumes configuration")
}
-func (v *UnixVolume) IOHandler() {
- for req := range v.queue {
- var result IOResponse
- switch req.method {
- case KeepGet:
- result.data, result.err = v.Read(req.loc)
- case KeepPut:
- result.err = v.Write(req.loc, req.data)
+// Discover adds a UnixVolume for every directory named "keep" that is
+// located at the top level of a device- or tmpfs-backed mount point
+// other than "/". It returns the number of volumes added.
+func (vs *unixVolumeAdder) Discover() int {
+ added := 0
+ f, err := os.Open(ProcMounts)
+ if err != nil {
+ log.Fatalf("opening %s: %s", ProcMounts, err)
+ }
+ scanner := bufio.NewScanner(f)
+ for scanner.Scan() {
+ args := strings.Fields(scanner.Text())
+ if err := scanner.Err(); err != nil {
+ log.Fatalf("reading %s: %s", ProcMounts, err)
}
- req.reply <- &result
+ dev, mount := args[0], args[1]
+ if mount == "/" {
+ continue
+ }
+ if dev != "tmpfs" && !strings.HasPrefix(dev, "/dev/") {
+ continue
+ }
+ keepdir := mount + "/keep"
+ if st, err := os.Stat(keepdir); err != nil || !st.IsDir() {
+ continue
+ }
+ // Set the -readonly flag (but only for this volume)
+ // if the filesystem is mounted readonly.
+ flagReadonlyWas := deprecated.flagReadonly
+ for _, fsopt := range strings.Split(args[3], ",") {
+ if fsopt == "ro" {
+ deprecated.flagReadonly = true
+ break
+ }
+ if fsopt == "rw" {
+ break
+ }
+ }
+ if err := vs.Set(keepdir); err != nil {
+ log.Printf("adding %q: %s", keepdir, err)
+ } else {
+ added++
+ }
+ deprecated.flagReadonly = flagReadonlyWas
}
+ return added
}
-func MakeUnixVolume(root string, serialize bool, readonly bool) *UnixVolume {
- v := &UnixVolume{
- root: root,
- queue: nil,
- readonly: readonly,
- }
- if serialize {
- v.queue = make(chan *IORequest)
- go v.IOHandler()
- }
- return v
+// A UnixVolume stores and retrieves blocks in a local directory.
+type UnixVolume struct {
+ Root string // path to the volume's root directory
+ ReadOnly bool
+ Serialize bool
+ DirectoryReplication int
+
+ // something to lock during IO, typically a sync.Mutex (or nil
+ // to skip locking)
+ locker sync.Locker
}
-func (v *UnixVolume) Get(loc string) ([]byte, error) {
- if v.queue == nil {
- return v.Read(loc)
+// Examples implements VolumeWithExamples.
+func (*UnixVolume) Examples() []Volume {
+ return []Volume{
+ &UnixVolume{
+ Root: "/mnt/local-disk",
+ Serialize: true,
+ DirectoryReplication: 1,
+ },
+ &UnixVolume{
+ Root: "/mnt/network-disk",
+ Serialize: false,
+ DirectoryReplication: 2,
+ },
}
- reply := make(chan *IOResponse)
- v.queue <- &IORequest{KeepGet, loc, nil, reply}
- response := <-reply
- return response.data, response.err
}
-func (v *UnixVolume) Put(loc string, block []byte) error {
- if v.readonly {
- return MethodDisabledError
+// Type implements Volume
+func (v *UnixVolume) Type() string {
+ return "Directory"
+}
+
+// Start implements Volume
+func (v *UnixVolume) Start() error {
+ if v.Serialize {
+ v.locker = &sync.Mutex{}
}
- if v.queue == nil {
- return v.Write(loc, block)
+ if !strings.HasPrefix(v.Root, "/") {
+ return fmt.Errorf("volume root does not start with '/': %q", v.Root)
}
- reply := make(chan *IOResponse)
- v.queue <- &IORequest{KeepPut, loc, block, reply}
- response := <-reply
- return response.err
+ if v.DirectoryReplication == 0 {
+ v.DirectoryReplication = 1
+ }
+ _, err := os.Stat(v.Root)
+ return err
}
+// Touch sets the timestamp for the given locator to the current time
func (v *UnixVolume) Touch(loc string) error {
- if v.readonly {
+ if v.ReadOnly {
return MethodDisabledError
}
p := v.blockPath(loc)
return err
}
defer f.Close()
+ if v.locker != nil {
+ v.locker.Lock()
+ defer v.locker.Unlock()
+ }
if e := lockfile(f); e != nil {
return e
}
defer unlockfile(f)
- now := time.Now().Unix()
- utime := syscall.Utimbuf{now, now}
- return syscall.Utime(p, &utime)
+ ts := syscall.NsecToTimespec(time.Now().UnixNano())
+ return syscall.UtimesNano(p, []syscall.Timespec{ts, ts})
}
+// Mtime returns the stored timestamp for the given locator.
func (v *UnixVolume) Mtime(loc string) (time.Time, error) {
p := v.blockPath(loc)
- if fi, err := os.Stat(p); err != nil {
+ fi, err := os.Stat(p)
+ if err != nil {
return time.Time{}, err
- } else {
- return fi.ModTime(), nil
}
+ return fi.ModTime(), nil
}
-// Read retrieves a block identified by the locator string "loc", and
-// returns its contents as a byte slice.
-//
-// If the block could not be opened or read, Read returns a nil slice
-// and the os.Error that was generated.
-//
-// If the block is present but its content hash does not match loc,
-// Read returns the block and a CorruptError. It is the caller's
-// responsibility to decide what (if anything) to do with the
-// corrupted data block.
-//
-func (v *UnixVolume) Read(loc string) ([]byte, error) {
- buf, err := ioutil.ReadFile(v.blockPath(loc))
- return buf, err
+// Lock the locker (if one is in use), open the file for reading, and
+// call the given function if and when the file is ready to read.
+func (v *UnixVolume) getFunc(path string, fn func(io.Reader) error) error {
+ if v.locker != nil {
+ v.locker.Lock()
+ defer v.locker.Unlock()
+ }
+ f, err := os.Open(path)
+ if err != nil {
+ return err
+ }
+ defer f.Close()
+ return fn(f)
+}
+
+// stat is os.Stat() with some extra sanity checks.
+func (v *UnixVolume) stat(path string) (os.FileInfo, error) {
+ stat, err := os.Stat(path)
+ if err == nil {
+ if stat.Size() < 0 {
+ err = os.ErrInvalid
+ } else if stat.Size() > BlockSize {
+ err = TooLongError
+ }
+ }
+ return stat, err
}
-// Write stores a block of data identified by the locator string
+// Get retrieves a block, copies it to the given slice, and returns
+// the number of bytes copied.
+func (v *UnixVolume) Get(ctx context.Context, loc string, buf []byte) (int, error) {
+ path := v.blockPath(loc)
+ stat, err := v.stat(path)
+ if err != nil {
+ return 0, v.translateError(err)
+ }
+ if stat.Size() > int64(len(buf)) {
+ return 0, TooLongError
+ }
+ var read int
+ size := int(stat.Size())
+ err = v.getFunc(path, func(rdr io.Reader) error {
+ read, err = io.ReadFull(rdr, buf[:size])
+ return err
+ })
+ return read, err
+}
+
+// Compare returns nil if Get(loc) would return the same content as
+// expect. It is functionally equivalent to Get() followed by
+// bytes.Compare(), but uses less memory.
+func (v *UnixVolume) Compare(loc string, expect []byte) error {
+ path := v.blockPath(loc)
+ if _, err := v.stat(path); err != nil {
+ return v.translateError(err)
+ }
+ return v.getFunc(path, func(rdr io.Reader) error {
+ return compareReaderWithBuf(rdr, expect, loc[:32])
+ })
+}
+
+// Put stores a block of data identified by the locator string
// "loc". It returns nil on success. If the volume is full, it
// returns a FullError. If the write fails due to some other error,
// that error is returned.
-//
-func (v *UnixVolume) Write(loc string, block []byte) error {
+func (v *UnixVolume) Put(loc string, block []byte) error {
+ if v.ReadOnly {
+ return MethodDisabledError
+ }
if v.IsFull() {
return FullError
}
}
bpath := v.blockPath(loc)
+ if v.locker != nil {
+ v.locker.Lock()
+ defer v.locker.Unlock()
+ }
if _, err := tmpfile.Write(block); err != nil {
log.Printf("%s: writing to %s: %s\n", v, bpath, err)
+ tmpfile.Close()
+ os.Remove(tmpfile.Name())
return err
}
if err := tmpfile.Close(); err != nil {
}
// Status returns a VolumeStatus struct describing the volume's
-// current state.
+// current state, or nil if an error occurs.
//
func (v *UnixVolume) Status() *VolumeStatus {
var fs syscall.Statfs_t
var devnum uint64
- if fi, err := os.Stat(v.root); err == nil {
+ if fi, err := os.Stat(v.Root); err == nil {
devnum = fi.Sys().(*syscall.Stat_t).Dev
} else {
log.Printf("%s: os.Stat: %s\n", v, err)
return nil
}
- err := syscall.Statfs(v.root, &fs)
+ err := syscall.Statfs(v.Root, &fs)
if err != nil {
log.Printf("%s: statfs: %s\n", v, err)
return nil
// uses fs.Blocks - fs.Bfree.
free := fs.Bavail * uint64(fs.Bsize)
used := (fs.Blocks - fs.Bfree) * uint64(fs.Bsize)
- return &VolumeStatus{v.root, devnum, free, used}
+ return &VolumeStatus{v.Root, devnum, free, used}
}
-// Index returns a list of blocks found on this volume which begin with
-// the specified prefix. If the prefix is an empty string, Index returns
-// a complete list of blocks.
+var blockDirRe = regexp.MustCompile(`^[0-9a-f]+$`)
+var blockFileRe = regexp.MustCompile(`^[0-9a-f]{32}$`)
+
+// IndexTo writes (to the given Writer) a list of blocks found on this
+// volume which begin with the specified prefix. If the prefix is an
+// empty string, IndexTo writes a complete list of blocks.
//
-// The return value is a multiline string (separated by
-// newlines). Each line is in the format
+// Each block is given in the format
//
-// locator+size modification-time
+// locator+size modification-time {newline}
//
// e.g.:
//
// e4d41e6fd68460e0e3fc18cc746959d2+67108864 1377796043
// e4de7a2810f5554cd39b36d8ddb132ff+67108864 1388701136
//
-func (v *UnixVolume) Index(prefix string) (output string) {
- filepath.Walk(v.root,
- func(path string, info os.FileInfo, err error) error {
- // This WalkFunc inspects each path in the volume
- // and prints an index line for all files that begin
- // with prefix.
- if err != nil {
- log.Printf("IndexHandler: %s: walking to %s: %s",
- v, path, err)
- return nil
- }
- locator := filepath.Base(path)
- // Skip directories that do not match prefix.
- // We know there is nothing interesting inside.
- if info.IsDir() &&
- !strings.HasPrefix(locator, prefix) &&
- !strings.HasPrefix(prefix, locator) {
- return filepath.SkipDir
+func (v *UnixVolume) IndexTo(prefix string, w io.Writer) error {
+ var lastErr error
+ rootdir, err := os.Open(v.Root)
+ if err != nil {
+ return err
+ }
+ defer rootdir.Close()
+ for {
+ names, err := rootdir.Readdirnames(1)
+ if err == io.EOF {
+ return lastErr
+ } else if err != nil {
+ return err
+ }
+ if !strings.HasPrefix(names[0], prefix) && !strings.HasPrefix(prefix, names[0]) {
+ // prefix excludes all blocks stored in this dir
+ continue
+ }
+ if !blockDirRe.MatchString(names[0]) {
+ continue
+ }
+ blockdirpath := filepath.Join(v.Root, names[0])
+ blockdir, err := os.Open(blockdirpath)
+ if err != nil {
+ log.Print("Error reading ", blockdirpath, ": ", err)
+ lastErr = err
+ continue
+ }
+ for {
+ fileInfo, err := blockdir.Readdir(1)
+ if err == io.EOF {
+ break
+ } else if err != nil {
+ log.Print("Error reading ", blockdirpath, ": ", err)
+ lastErr = err
+ break
}
- // Skip any file that is not apparently a locator, e.g. .meta files
- if !IsValidLocator(locator) {
- return nil
+ name := fileInfo[0].Name()
+ if !strings.HasPrefix(name, prefix) {
+ continue
}
- // Print filenames beginning with prefix
- if !info.IsDir() && strings.HasPrefix(locator, prefix) {
- output = output + fmt.Sprintf(
- "%s+%d %d\n", locator, info.Size(), info.ModTime().Unix())
+ if !blockFileRe.MatchString(name) {
+ continue
}
- return nil
- })
-
- return
+ _, err = fmt.Fprint(w,
+ name,
+ "+", fileInfo[0].Size(),
+ " ", fileInfo[0].ModTime().UnixNano(),
+ "\n")
+ }
+ blockdir.Close()
+ }
}
-func (v *UnixVolume) Delete(loc string) error {
+// Trash trashes the block data from the unix storage
+// If TrashLifetime == 0, the block is deleted
+// Else, the block is renamed as path/{loc}.trash.{deadline},
+// where deadline = now + TrashLifetime
+func (v *UnixVolume) Trash(loc string) error {
// Touch() must be called before calling Write() on a block. Touch()
// also uses lockfile(). This avoids a race condition between Write()
- // and Delete() because either (a) the file will be deleted and Touch()
+ // and Trash() because either (a) the file will be trashed and Touch()
// will signal to the caller that the file is not present (and needs to
// be re-written), or (b) Touch() will update the file's timestamp and
- // Delete() will read the correct up-to-date timestamp and choose not to
- // delete the file.
+ // Trash() will read the correct up-to-date timestamp and choose not to
+ // trash the file.
- if v.readonly {
+ if v.ReadOnly {
return MethodDisabledError
}
+ if v.locker != nil {
+ v.locker.Lock()
+ defer v.locker.Unlock()
+ }
p := v.blockPath(loc)
f, err := os.OpenFile(p, os.O_RDWR|os.O_APPEND, 0644)
if err != nil {
}
defer unlockfile(f)
- // If the block has been PUT in the last blob_signature_ttl
+ // If the block has been PUT in the last blobSignatureTTL
// seconds, return success without removing the block. This
// protects data from garbage collection until it is no longer
// possible for clients to retrieve the unreferenced blocks
// anyway (because the permission signatures have expired).
if fi, err := os.Stat(p); err != nil {
return err
- } else {
- if time.Since(fi.ModTime()) < blob_signature_ttl {
- return nil
+ } else if time.Since(fi.ModTime()) < time.Duration(theConfig.BlobSignatureTTL) {
+ return nil
+ }
+
+ if theConfig.TrashLifetime == 0 {
+ return os.Remove(p)
+ }
+ return os.Rename(p, fmt.Sprintf("%v.trash.%d", p, time.Now().Add(theConfig.TrashLifetime.Duration()).Unix()))
+}
+
+// Untrash moves block from trash back into store
+// Look for path/{loc}.trash.{deadline} in storage,
+// and rename the first such file as path/{loc}
+func (v *UnixVolume) Untrash(loc string) (err error) {
+ if v.ReadOnly {
+ return MethodDisabledError
+ }
+
+ files, err := ioutil.ReadDir(v.blockDir(loc))
+ if err != nil {
+ return err
+ }
+
+ if len(files) == 0 {
+ return os.ErrNotExist
+ }
+
+ foundTrash := false
+ prefix := fmt.Sprintf("%v.trash.", loc)
+ for _, f := range files {
+ if strings.HasPrefix(f.Name(), prefix) {
+ foundTrash = true
+ err = os.Rename(v.blockPath(f.Name()), v.blockPath(loc))
+ if err == nil {
+ break
+ }
}
}
- return os.Remove(p)
+
+ if foundTrash == false {
+ return os.ErrNotExist
+ }
+
+ return
}
// blockDir returns the fully qualified directory name for the directory
// where loc is (or would be) stored on this volume.
func (v *UnixVolume) blockDir(loc string) string {
- return filepath.Join(v.root, loc[0:3])
+ return filepath.Join(v.Root, loc[0:3])
}
// blockPath returns the fully qualified pathname for the path to loc
}
// IsFull returns true if the free space on the volume is less than
-// MIN_FREE_KILOBYTES.
+// MinFreeKilobytes.
//
func (v *UnixVolume) IsFull() (isFull bool) {
- fullSymlink := v.root + "/full"
+ fullSymlink := v.Root + "/full"
// Check if the volume has been marked as full in the last hour.
if link, err := os.Readlink(fullSymlink); err == nil {
}
if avail, err := v.FreeDiskSpace(); err == nil {
- isFull = avail < MIN_FREE_KILOBYTES
+ isFull = avail < MinFreeKilobytes
} else {
log.Printf("%s: FreeDiskSpace: %s\n", v, err)
isFull = false
//
func (v *UnixVolume) FreeDiskSpace() (free uint64, err error) {
var fs syscall.Statfs_t
- err = syscall.Statfs(v.root, &fs)
+ err = syscall.Statfs(v.Root, &fs)
if err == nil {
// Statfs output is not guaranteed to measure free
// space in terms of 1K blocks.
}
func (v *UnixVolume) String() string {
- return fmt.Sprintf("[UnixVolume %s]", v.root)
+ return fmt.Sprintf("[UnixVolume %s]", v.Root)
}
+// Writable returns false if all future Put, Mtime, and Delete calls
+// are expected to fail.
func (v *UnixVolume) Writable() bool {
- return !v.readonly
+ return !v.ReadOnly
+}
+
+// Replication returns the number of replicas promised by the
+// underlying device (as specified in configuration).
+func (v *UnixVolume) Replication() int {
+ return v.DirectoryReplication
}
// lockfile and unlockfile use flock(2) to manage kernel file locks.
func unlockfile(f *os.File) error {
return syscall.Flock(int(f.Fd()), syscall.LOCK_UN)
}
+
+// Where appropriate, translate a more specific filesystem error to an
+// error recognized by handlers, like os.ErrNotExist.
+func (v *UnixVolume) translateError(err error) error {
+ switch err.(type) {
+ case *os.PathError:
+ // stat() returns a PathError if the parent directory
+ // (not just the file itself) is missing
+ return os.ErrNotExist
+ default:
+ return err
+ }
+}
+
+var unixTrashLocRegexp = regexp.MustCompile(`/([0-9a-f]{32})\.trash\.(\d+)$`)
+
+// EmptyTrash walks hierarchy looking for {hash}.trash.*
+// and deletes those with deadline < now.
+func (v *UnixVolume) EmptyTrash() {
+ var bytesDeleted, bytesInTrash int64
+ var blocksDeleted, blocksInTrash int
+
+ err := filepath.Walk(v.Root, func(path string, info os.FileInfo, err error) error {
+ if err != nil {
+ log.Printf("EmptyTrash: filepath.Walk: %v: %v", path, err)
+ return nil
+ }
+ if info.Mode().IsDir() {
+ return nil
+ }
+ matches := unixTrashLocRegexp.FindStringSubmatch(path)
+ if len(matches) != 3 {
+ return nil
+ }
+ deadline, err := strconv.ParseInt(matches[2], 10, 64)
+ if err != nil {
+ log.Printf("EmptyTrash: %v: ParseInt(%v): %v", path, matches[2], err)
+ return nil
+ }
+ bytesInTrash += info.Size()
+ blocksInTrash++
+ if deadline > time.Now().Unix() {
+ return nil
+ }
+ err = os.Remove(path)
+ if err != nil {
+ log.Printf("EmptyTrash: Remove %v: %v", path, err)
+ return nil
+ }
+ bytesDeleted += info.Size()
+ blocksDeleted++
+ return nil
+ })
+
+ if err != nil {
+ log.Printf("EmptyTrash error for %v: %v", v.String(), err)
+ }
+
+ log.Printf("EmptyTrash stats for %v: Deleted %v bytes in %v blocks. Remaining in trash: %v bytes in %v blocks.", v.String(), bytesDeleted, blocksDeleted, bytesInTrash-bytesDeleted, blocksInTrash-blocksDeleted)
+}
projects / arvados.git / blobdiff