package main
import (
- "bytes"
+ "bufio"
+ "errors"
+ "flag"
"fmt"
"io"
"io/ioutil"
"time"
)
+type unixVolumeAdder struct {
+ *volumeSet
+}
+
+func (vs *unixVolumeAdder) Set(value string) error {
+ if dirs := strings.Split(value, ","); 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
+ }
+ if len(value) == 0 || value[0] != '/' {
+ return errors.New("Invalid volume: must begin with '/'.")
+ }
+ if _, err := os.Stat(value); err != nil {
+ return err
+ }
+ var locker sync.Locker
+ if flagSerializeIO {
+ locker = &sync.Mutex{}
+ }
+ *vs.volumeSet = append(*vs.volumeSet, &UnixVolume{
+ root: value,
+ locker: locker,
+ readonly: flagReadonly,
+ })
+ return nil
+}
+
+func init() {
+ flag.Var(
+ &unixVolumeAdder{&volumes},
+ "volumes",
+ "Deprecated synonym for -volume.")
+ flag.Var(
+ &unixVolumeAdder{&volumes},
+ "volume",
+ "Local storage directory. Can be given more than once to add multiple directories. If none are supplied, the default is to use all directories named \"keep\" that exist in the top level directory of a mount point at startup time. Can be a comma-separated list, but this is deprecated: use multiple -volume arguments instead.")
+}
+
+// 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)
+ }
+ 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 := flagReadonly
+ for _, fsopt := range strings.Split(args[3], ",") {
+ if fsopt == "ro" {
+ flagReadonly = true
+ break
+ }
+ if fsopt == "rw" {
+ break
+ }
+ }
+ if err := vs.Set(keepdir); err != nil {
+ log.Printf("adding %q: %s", keepdir, err)
+ } else {
+ added++
+ }
+ flagReadonly = flagReadonlyWas
+ }
+ return added
+}
+
// A UnixVolume stores and retrieves blocks in a local directory.
type UnixVolume struct {
// path to the volume's root directory
return stat, err
}
-// Get retrieves a block identified by the locator string "loc", and
-// returns its contents as a byte slice.
-//
-// Get returns a nil buffer IFF it returns a non-nil error.
-func (v *UnixVolume) Get(loc string) ([]byte, error) {
+// Get retrieves a block, copies it to the given slice, and returns
+// the number of bytes copied.
+func (v *UnixVolume) Get(loc string, buf []byte) (int, error) {
path := v.blockPath(loc)
stat, err := v.stat(path)
if err != nil {
- return nil, err
+ return 0, v.translateError(err)
+ }
+ if stat.Size() > int64(len(buf)) {
+ return 0, TooLongError
}
- buf := bufs.Get(int(stat.Size()))
+ var read int
+ size := int(stat.Size())
err = v.getFunc(path, func(rdr io.Reader) error {
- _, err = io.ReadFull(rdr, buf)
+ read, err = io.ReadFull(rdr, buf[:size])
return err
})
- if err != nil {
- bufs.Put(buf)
- return nil, err
- }
- return buf, nil
+ return read, err
}
// Compare returns nil if Get(loc) would return the same content as
// bytes.Compare(), but uses less memory.
func (v *UnixVolume) Compare(loc string, expect []byte) error {
path := v.blockPath(loc)
- stat, err := v.stat(path)
- if err != nil {
- return err
- }
- bufLen := 1 << 20
- if int64(bufLen) > stat.Size() {
- bufLen = int(stat.Size())
- if bufLen < 1 {
- // len(buf)==0 would prevent us from handling
- // empty files the same way as non-empty
- // files, because reading 0 bytes at a time
- // never reaches EOF.
- bufLen = 1
- }
+ if _, err := v.stat(path); err != nil {
+ return v.translateError(err)
}
- cmp := expect
- buf := make([]byte, bufLen)
return v.getFunc(path, func(rdr io.Reader) error {
- // Loop invariants: all data read so far matched what
- // we expected, and the first N bytes of cmp are
- // expected to equal the next N bytes read from
- // reader.
- for {
- n, err := rdr.Read(buf)
- if n > len(cmp) || bytes.Compare(cmp[:n], buf[:n]) != 0 {
- return collisionOrCorrupt(loc[:32], expect[:len(expect)-len(cmp)], buf[:n], rdr)
- }
- cmp = cmp[n:]
- if err == io.EOF {
- if len(cmp) != 0 {
- return collisionOrCorrupt(loc[:32], expect[:len(expect)-len(cmp)], nil, nil)
- }
- return nil
- } else if err != nil {
- return err
- }
- }
+ return compareReaderWithBuf(rdr, expect, loc[:32])
})
}
}
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
if !strings.HasPrefix(name, prefix) {
continue
}
+ if !blockFileRe.MatchString(name) {
+ continue
+ }
_, err = fmt.Fprint(w,
name,
"+", fileInfo[0].Size(),
}
}
-// Delete deletes the block data from the unix storage
-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 {
return MethodDisabledError
return nil
}
}
- return os.Remove(p)
+
+ if trashLifetime == 0 {
+ return os.Remove(p)
+ }
+ return os.Rename(p, fmt.Sprintf("%v.trash.%d", p, time.Now().Add(trashLifetime).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
+ }
+ }
+ }
+
+ if foundTrash == false {
+ return os.ErrNotExist
+ }
+
+ return
}
// blockDir returns the fully qualified directory name for the directory
return !v.readonly
}
+func (v *UnixVolume) Replication() int {
+ return 1
+}
+
// lockfile and unlockfile use flock(2) to manage kernel file locks.
func lockfile(f *os.File) error {
return syscall.Flock(int(f.Fd()), syscall.LOCK_EX)
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