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md_journal.go
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md_journal.go
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// Copyright 2016 Keybase Inc. All rights reserved.
// Use of this source code is governed by a BSD
// license that can be found in the LICENSE file.
package libkbfs
import (
"path/filepath"
"time"
"github.com/keybase/client/go/kbfs/idutil"
"github.com/keybase/client/go/kbfs/ioutil"
"github.com/keybase/client/go/kbfs/kbfscodec"
"github.com/keybase/client/go/kbfs/kbfscrypto"
"github.com/keybase/client/go/kbfs/kbfsmd"
"github.com/keybase/client/go/kbfs/tlf"
"github.com/keybase/client/go/logger"
"github.com/keybase/client/go/protocol/keybase1"
"github.com/pkg/errors"
"golang.org/x/net/context"
)
// ImmutableBareRootMetadata is a thin wrapper around a
// BareRootMetadata and a kbfsmd.ExtraMetadata that takes ownership of it
// and does not ever modify it again. Thus, its MdID can be calculated
// and stored along with a local timestamp. ImmutableBareRootMetadata
// objects can be assumed to never alias a (modifiable)
// BareRootMetadata.
//
// Note that kbfsmd.MakeID() on an ImmutableBareRootMetadata will
// compute the wrong result, since anonymous fields of interface type
// are not encoded inline by the codec. Use
// kbfsmd.MakeID(ibrmd.BareRootMetadata) instead.
//
// TODO: Move this to bare_root_metadata.go if it's used in more
// places.
type ImmutableBareRootMetadata struct {
kbfsmd.RootMetadata
extra kbfsmd.ExtraMetadata
mdID kbfsmd.ID
localTimestamp time.Time
}
// MakeImmutableBareRootMetadata makes a new ImmutableBareRootMetadata
// from the given BareRootMetadata and its corresponding MdID.
func MakeImmutableBareRootMetadata(
rmd kbfsmd.RootMetadata, extra kbfsmd.ExtraMetadata, mdID kbfsmd.ID,
localTimestamp time.Time) ImmutableBareRootMetadata {
if mdID == (kbfsmd.ID{}) {
panic("zero mdID passed to MakeImmutableBareRootMetadata")
}
return ImmutableBareRootMetadata{rmd, extra, mdID, localTimestamp}
}
// MakeBareTlfHandleWithExtra makes a BareTlfHandle for this
// ImmutableBareRootMetadata. Should be used only by servers and MDOps.
func (ibrmd ImmutableBareRootMetadata) MakeBareTlfHandleWithExtra() (
tlf.Handle, error) {
return ibrmd.RootMetadata.MakeBareTlfHandle(ibrmd.extra)
}
// mdJournal stores a single ordered list of metadata IDs for a (TLF,
// user, device) tuple, along with the associated metadata objects, in
// flat files on disk in a directory. The directory may be shared with
// other things, but it is assumed that any subdirectories created by
// mdJournal is not used by anything else.
//
// The directory layout looks like:
//
// dir/md_journal/EARLIEST
// dir/md_journal/LATEST
// dir/md_journal/0...001
// dir/md_journal/0...002
// dir/md_journal/0...fff
// dir/mds/0100/0...01/data
// dir/mds/0100/0...01/info.json
// ...
// dir/mds/01ff/f...ff/data
// dir/mds/01ff/f...ff/info.json
// dir/wkbv3/0100...01
// ...
// dir/wkbv3/0100...ff
// dir/rkbv3/0100...01
// ...
// dir/rkbv3/0100...ff
//
// There's a single journal subdirectory; the journal ordinals are
// just Revisions, and the journal entries are just MdIDs.
//
// The Metadata objects are stored separately in dir/mds. Each MD has
// its own subdirectory with its ID truncated to 17 bytes (34
// characters) as a name. The MD subdirectories are splayed over (# of
// possible hash types) * 256 subdirectories -- one byte for the hash
// type (currently only one) plus the first byte of the hash data --
// using the first four characters of the name to keep the number of
// directories in dir itself to a manageable number, similar to git.
// Each block directory has data, which is the raw MD data that should
// hash to the MD ID, and info.json, which contains the version and
// timestamp info for that MD. Future versions of the journal might
// add more files to this directory; if any code is written to move
// MDs around, it should be careful to preserve any unknown files in
// an MD directory.
//
// Writer (reader) key bundles for V3 metadata objects are stored
// separately in dir/wkbv3 (dir/rkbv3). The number of bundles is
// small, so no need to splay them.
//
// TODO: Garbage-collect unreferenced key bundles.
//
// The maximum number of characters added to the root dir by an MD
// journal is 50:
//
// /mds/01ff/f...(30 characters total)...ff/info.json
//
// This covers even the temporary files created in convertToBranch and
// resolveAndClear, which create paths like
//
// /md_journal123456789/0...(16 characters total)...001
//
// which have only 37 characters.
//
// mdJournal is not goroutine-safe, so any code that uses it must
// guarantee that only one goroutine at a time calls its functions.
type mdJournal struct {
// key is assumed to be the VerifyingKey of a device owned by
// uid, and both uid and key are assumed constant for the
// lifetime of this object.
uid keybase1.UID
key kbfscrypto.VerifyingKey
codec kbfscodec.Codec
crypto cryptoPure
clock Clock
teamMemChecker kbfsmd.TeamMembershipChecker
osg idutil.OfflineStatusGetter
tlfID tlf.ID
mdVer kbfsmd.MetadataVer
dir string
log logger.Logger
deferLog logger.Logger
j mdIDJournal
// branchID is the kbfsmd.BranchID that every MD in the journal is set
// to, except for when it is kbfsmd.PendingLocalSquashBranchID, in which
// case the journal is a bunch of MDs with a null branchID
// followed by a bunch of MDs with bid =
// kbfsmd.PendingLocalSquashBranchID.
//
// branchID doesn't need to be persisted, even if the journal
// becomes empty, since on a restart the branch ID is retrieved
// from the server (via GetUnmergedForTLF).
branchID kbfsmd.BranchID
// Set only when the journal becomes empty due to
// flushing. This doesn't need to be persisted for the same
// reason as branchID.
lastMdID kbfsmd.ID
}
func makeMDJournalWithIDJournal(
ctx context.Context, uid keybase1.UID, key kbfscrypto.VerifyingKey,
codec kbfscodec.Codec, crypto cryptoPure, clock Clock,
teamMemChecker kbfsmd.TeamMembershipChecker, osg idutil.OfflineStatusGetter,
tlfID tlf.ID, mdVer kbfsmd.MetadataVer, dir string, idJournal mdIDJournal,
log logger.Logger) (*mdJournal, error) {
if uid == keybase1.UID("") {
return nil, errors.New("Empty user")
}
if key == (kbfscrypto.VerifyingKey{}) {
return nil, errors.New("Empty verifying key")
}
deferLog := log.CloneWithAddedDepth(1)
journal := mdJournal{
uid: uid,
key: key,
codec: codec,
crypto: crypto,
clock: clock,
teamMemChecker: teamMemChecker,
osg: osg,
tlfID: tlfID,
mdVer: mdVer,
dir: dir,
log: log,
deferLog: deferLog,
j: idJournal,
}
_, earliest, _, _, err := journal.getEarliestWithExtra(ctx, false)
if err != nil {
return nil, err
}
latest, err := journal.getLatest(ctx, false)
if err != nil {
return nil, err
}
if (earliest == nil) != (latest == ImmutableBareRootMetadata{}) {
return nil, errors.Errorf("has earliest=%t != has latest=%t",
earliest != nil,
latest != ImmutableBareRootMetadata{})
}
if earliest != nil {
if earliest.BID() != latest.BID() &&
!(earliest.BID() == kbfsmd.NullBranchID &&
latest.BID() == kbfsmd.PendingLocalSquashBranchID) {
return nil, errors.Errorf(
"earliest.BID=%s != latest.BID=%s",
earliest.BID(), latest.BID())
}
log.CDebugf(ctx, "Initializing with branch ID %s", latest.BID())
journal.branchID = latest.BID()
}
return &journal, nil
}
func mdJournalPath(dir string) string {
return filepath.Join(dir, "md_journal")
}
func makeMDJournal(
ctx context.Context, uid keybase1.UID, key kbfscrypto.VerifyingKey,
codec kbfscodec.Codec, crypto cryptoPure, clock Clock,
teamMemChecker kbfsmd.TeamMembershipChecker, osg idutil.OfflineStatusGetter,
tlfID tlf.ID, mdVer kbfsmd.MetadataVer, dir string,
log logger.Logger) (*mdJournal, error) {
journalDir := mdJournalPath(dir)
idJournal, err := makeMdIDJournal(codec, journalDir)
if err != nil {
return nil, err
}
return makeMDJournalWithIDJournal(
ctx, uid, key, codec, crypto, clock, teamMemChecker, osg, tlfID, mdVer,
dir, idJournal, log)
}
// The functions below are for building various paths.
func (j mdJournal) mdsPath() string {
return filepath.Join(j.dir, "mds")
}
func (j mdJournal) writerKeyBundlesV3Path() string {
return filepath.Join(j.dir, "wkbv3")
}
func (j mdJournal) readerKeyBundlesV3Path() string {
return filepath.Join(j.dir, "rkbv3")
}
// The final components of the paths below are truncated to 34
// characters, which corresponds to 16 random bytes (since the first
// byte is a hash type) or 128 random bits, which means that the
// expected number of MDs generated before getting a path collision is
// 2^64 (see
// https://en.wikipedia.org/wiki/Birthday_problem#Cast_as_a_collision_problem
// ). The full ID can be recovered just by hashing the data again with
// the same hash type.
func (j mdJournal) writerKeyBundleV3Path(id kbfsmd.TLFWriterKeyBundleID) string {
idStr := id.String()
return filepath.Join(j.writerKeyBundlesV3Path(), idStr[:34])
}
func (j mdJournal) readerKeyBundleV3Path(id kbfsmd.TLFReaderKeyBundleID) string {
idStr := id.String()
return filepath.Join(j.readerKeyBundlesV3Path(), idStr[:34])
}
func (j mdJournal) mdJournalDirs() []string {
return []string{
mdJournalPath(j.dir), j.mdsPath(),
j.writerKeyBundlesV3Path(), j.readerKeyBundlesV3Path(),
}
}
func (j mdJournal) mdPath(id kbfsmd.ID) string {
idStr := id.String()
return filepath.Join(j.mdsPath(), idStr[:4], idStr[4:34])
}
func (j mdJournal) mdDataPath(id kbfsmd.ID) string {
return filepath.Join(j.mdPath(id), "data")
}
func (j mdJournal) mdInfoPath(id kbfsmd.ID) string {
return filepath.Join(j.mdPath(id), "info.json")
}
// mdInfo is the structure stored in mdInfoPath(id).
//
// TODO: Handle unknown fields? We'd have to build a handler for this,
// since the Go JSON library doesn't support it natively.
type mdInfo struct {
Timestamp time.Time
Version kbfsmd.MetadataVer
}
func (j mdJournal) getMDInfo(id kbfsmd.ID) (time.Time, kbfsmd.MetadataVer, error) {
var info mdInfo
err := ioutil.DeserializeFromJSONFile(j.mdInfoPath(id), &info)
if err != nil {
return time.Time{}, kbfsmd.MetadataVer(-1), err
}
return info.Timestamp, info.Version, nil
}
// putMDInfo assumes that the parent directory of j.mdInfoPath(id)
// (which is j.mdPath(id)) has already been created.
func (j mdJournal) putMDInfo(
id kbfsmd.ID, timestamp time.Time, version kbfsmd.MetadataVer) error {
info := mdInfo{timestamp, version}
return ioutil.SerializeToJSONFile(info, j.mdInfoPath(id))
}
// getExtraMetadata gets the extra metadata corresponding to the given
// IDs, if any, after checking them.
func (j mdJournal) getExtraMetadata(
wkbID kbfsmd.TLFWriterKeyBundleID, rkbID kbfsmd.TLFReaderKeyBundleID,
wkbNew, rkbNew bool) (kbfsmd.ExtraMetadata, error) {
if (wkbID == kbfsmd.TLFWriterKeyBundleID{}) !=
(rkbID == kbfsmd.TLFReaderKeyBundleID{}) {
return nil, errors.Errorf(
"wkbID is empty (%t) != rkbID is empty (%t)",
wkbID == kbfsmd.TLFWriterKeyBundleID{},
rkbID == kbfsmd.TLFReaderKeyBundleID{})
}
if wkbID == (kbfsmd.TLFWriterKeyBundleID{}) {
return nil, nil
}
wkb, err := kbfsmd.DeserializeTLFWriterKeyBundleV3(
j.codec, j.writerKeyBundleV3Path(wkbID))
if err != nil {
return nil, err
}
err = kbfsmd.CheckWKBID(j.codec, wkbID, wkb)
if err != nil {
return nil, err
}
rkb, err := kbfsmd.DeserializeTLFReaderKeyBundleV3(
j.codec, j.readerKeyBundleV3Path(rkbID))
if err != nil {
return nil, err
}
err = kbfsmd.CheckRKBID(j.codec, rkbID, rkb)
if err != nil {
return nil, err
}
return kbfsmd.NewExtraMetadataV3(wkb, rkb, wkbNew, rkbNew), nil
}
func (j mdJournal) putExtraMetadata(rmd kbfsmd.RootMetadata, extra kbfsmd.ExtraMetadata) (
wkbNew, rkbNew bool, err error) {
wkbID := rmd.GetTLFWriterKeyBundleID()
rkbID := rmd.GetTLFReaderKeyBundleID()
if extra == nil {
if wkbID != (kbfsmd.TLFWriterKeyBundleID{}) {
panic(errors.Errorf("unexpected non-nil wkbID %s", wkbID))
}
if rkbID != (kbfsmd.TLFReaderKeyBundleID{}) {
panic(errors.Errorf("unexpected non-nil rkbID %s", rkbID))
}
return false, false, nil
}
if wkbID == (kbfsmd.TLFWriterKeyBundleID{}) {
panic("writer key bundle ID is empty")
}
if rkbID == (kbfsmd.TLFReaderKeyBundleID{}) {
panic("reader key bundle ID is empty")
}
extraV3, ok := extra.(*kbfsmd.ExtraMetadataV3)
if !ok {
return false, false, errors.New("Invalid extra metadata")
}
// TODO: We lose extraV3.wkbNew and extraV3.rkbNew here. Store
// it as part of the mdInfo, so we don't needlessly send it
// while flushing.
err = kbfsmd.CheckWKBID(j.codec, wkbID, extraV3.GetWriterKeyBundle())
if err != nil {
return false, false, err
}
err = kbfsmd.CheckRKBID(j.codec, rkbID, extraV3.GetReaderKeyBundle())
if err != nil {
return false, false, err
}
err = kbfscodec.SerializeToFileIfNotExist(
j.codec, extraV3.GetWriterKeyBundle(), j.writerKeyBundleV3Path(wkbID))
if err != nil {
return false, false, err
}
err = kbfscodec.SerializeToFileIfNotExist(
j.codec, extraV3.GetReaderKeyBundle(), j.readerKeyBundleV3Path(rkbID))
if err != nil {
return false, false, err
}
return extraV3.IsWriterKeyBundleNew(), extraV3.IsReaderKeyBundleNew(), nil
}
// getMDAndExtra verifies the MD data, the writer signature (but not
// the key), and the extra metadata for the given ID and returns
// them. It also returns the last-modified timestamp of the
// file. verifyBranchID should be false only when called from
// makeMDJournal, i.e. when figuring out what to set j.branchID in the
// first place.
//
// It returns a kbfsmd.MutableRootMetadata so that it can be put in a
// RootMetadataSigned object.
func (j mdJournal) getMDAndExtra(ctx context.Context, entry mdIDJournalEntry,
verifyBranchID bool) (
kbfsmd.MutableRootMetadata, kbfsmd.ExtraMetadata, time.Time, error) {
// Read info.
timestamp, version, err := j.getMDInfo(entry.ID)
if err != nil {
return nil, nil, time.Time{}, err
}
// Read data.
p := j.mdDataPath(entry.ID)
data, err := ioutil.ReadFile(p)
if err != nil {
return nil, nil, time.Time{}, err
}
rmd, err := kbfsmd.DecodeRootMetadata(
j.codec, j.tlfID, version, j.mdVer, data)
if err != nil {
return nil, nil, time.Time{}, err
}
// Check integrity.
mdID, err := kbfsmd.MakeID(j.codec, rmd)
if err != nil {
return nil, nil, time.Time{}, err
}
if mdID != entry.ID {
return nil, nil, time.Time{}, errors.Errorf(
"Metadata ID mismatch: expected %s, got %s",
entry.ID, mdID)
}
err = rmd.IsLastModifiedBy(j.uid, j.key)
if err != nil {
return nil, nil, time.Time{}, err
}
extra, err := j.getExtraMetadata(
rmd.GetTLFWriterKeyBundleID(), rmd.GetTLFReaderKeyBundleID(),
entry.WKBNew, entry.RKBNew)
if err != nil {
return nil, nil, time.Time{}, err
}
err = rmd.IsValidAndSigned(
ctx, j.codec, j.teamMemChecker, extra, j.key,
j.osg.OfflineAvailabilityForID(j.tlfID))
if err != nil {
return nil, nil, time.Time{}, err
}
if verifyBranchID && rmd.BID() != j.branchID &&
!(rmd.BID() == kbfsmd.NullBranchID && j.branchID == kbfsmd.PendingLocalSquashBranchID) {
return nil, nil, time.Time{}, errors.Errorf(
"Branch ID mismatch: expected %s, got %s",
j.branchID, rmd.BID())
}
return rmd, extra, timestamp, nil
}
// putMD stores the given metadata under its ID, if it's not already
// stored. The extra metadata is put separately, since sometimes,
// (e.g., when converting to a branch) we don't need to put it.
func (j mdJournal) putMD(rmd kbfsmd.RootMetadata) (kbfsmd.ID, error) {
// TODO: Make crypto and RMD wrap errors.
err := rmd.IsLastModifiedBy(j.uid, j.key)
if err != nil {
return kbfsmd.ID{}, err
}
id, err := kbfsmd.MakeID(j.codec, rmd)
if err != nil {
return kbfsmd.ID{}, err
}
_, err = ioutil.Stat(j.mdDataPath(id))
if ioutil.IsNotExist(err) {
// Continue on.
} else if err != nil {
return kbfsmd.ID{}, err
} else {
// Entry exists, so nothing else to do.
return id, nil
}
err = kbfscodec.SerializeToFileIfNotExist(
j.codec, rmd, j.mdDataPath(id))
if err != nil {
return kbfsmd.ID{}, err
}
err = j.putMDInfo(id, j.clock.Now(), rmd.Version())
if err != nil {
return kbfsmd.ID{}, err
}
return id, nil
}
// removeMD removes the metadata (which must exist) with the given ID.
func (j *mdJournal) removeMD(id kbfsmd.ID) error {
path := j.mdPath(id)
err := ioutil.RemoveAll(path)
if err != nil {
return err
}
// Remove the parent (splayed) directory (which should exist)
// if it's empty.
err = ioutil.Remove(filepath.Dir(path))
if ioutil.IsExist(err) {
err = nil
}
return err
}
// getEarliestWithExtra returns a kbfsmd.MutableRootMetadata so that it
// can be put in a RootMetadataSigned object.
func (j mdJournal) getEarliestWithExtra(
ctx context.Context, verifyBranchID bool) (
kbfsmd.ID, kbfsmd.MutableRootMetadata, kbfsmd.ExtraMetadata, time.Time, error) {
entry, exists, err := j.j.getEarliestEntry()
if err != nil {
return kbfsmd.ID{}, nil, nil, time.Time{}, err
}
if !exists {
return kbfsmd.ID{}, nil, nil, time.Time{}, nil
}
earliest, extra, timestamp, err :=
j.getMDAndExtra(ctx, entry, verifyBranchID)
if err != nil {
return kbfsmd.ID{}, nil, nil, time.Time{}, err
}
return entry.ID, earliest, extra, timestamp, nil
}
func (j mdJournal) getLatest(ctx context.Context, verifyBranchID bool) (
ImmutableBareRootMetadata, error) {
entry, exists, err := j.j.getLatestEntry()
if err != nil {
return ImmutableBareRootMetadata{}, err
}
if !exists {
return ImmutableBareRootMetadata{}, nil
}
latest, extra, timestamp, err :=
j.getMDAndExtra(ctx, entry, verifyBranchID)
if err != nil {
return ImmutableBareRootMetadata{}, err
}
return MakeImmutableBareRootMetadata(
latest, extra, entry.ID, timestamp), nil
}
func (j mdJournal) checkGetParams(ctx context.Context) (
ImmutableBareRootMetadata, error) {
head, err := j.getLatest(ctx, true)
if err != nil {
return ImmutableBareRootMetadata{}, err
}
if head == (ImmutableBareRootMetadata{}) {
return ImmutableBareRootMetadata{}, nil
}
ok, err := isReader(
ctx, j.teamMemChecker, j.uid, head.RootMetadata, head.extra)
if err != nil {
return ImmutableBareRootMetadata{}, err
}
if !ok {
// TODO: Use a non-server error.
return ImmutableBareRootMetadata{}, kbfsmd.ServerErrorUnauthorized{}
}
return head, nil
}
func (j *mdJournal) convertToBranch(
ctx context.Context, bid kbfsmd.BranchID, signer kbfscrypto.Signer,
codec kbfscodec.Codec, tlfID tlf.ID, mdcache MDCache) (err error) {
if j.branchID != kbfsmd.NullBranchID {
return errors.Errorf(
"convertToBranch called with j.branchID=%s", j.branchID)
}
if bid == kbfsmd.NullBranchID {
return errors.Errorf(
"convertToBranch called with null branchID")
}
earliestRevision, err := j.j.readEarliestRevision()
if err != nil {
return err
}
latestRevision, err := j.j.readLatestRevision()
if err != nil {
return err
}
j.log.CDebugf(
ctx, "rewriting MDs %s to %s", earliestRevision, latestRevision)
_, allEntries, err := j.j.getEntryRange(
earliestRevision, latestRevision)
if err != nil {
return err
}
j.log.CDebugf(ctx, "New branch ID=%s", bid)
journalTempDir, err := ioutil.TempDir(j.dir, "md_journal")
if err != nil {
return err
}
j.log.CDebugf(ctx, "Using temp dir %s for rewriting", journalTempDir)
mdsToRemove := make([]kbfsmd.ID, 0, len(allEntries))
defer func() {
// If we crash here and leave behind the tempdir, it
// won't be cleaned up automatically when the journal
// is completely drained, but it'll be cleaned up when
// the parent journal (i.e., tlfJournal) is completely
// drained. As for the entries, they'll be cleaned up
// the next time the journal is completely drained.
j.log.CDebugf(ctx, "Removing temp dir %s and %d old MDs",
journalTempDir, len(mdsToRemove))
removeErr := ioutil.RemoveAll(journalTempDir)
if removeErr != nil {
j.log.CWarningf(ctx,
"Error when removing temp dir %s: %+v",
journalTempDir, removeErr)
}
// Garbage-collect the unnecessary MD entries.
for _, id := range mdsToRemove {
removeErr := j.removeMD(id)
if removeErr != nil {
j.log.CWarningf(ctx, "Error when removing old MD %s: %+v",
id, removeErr)
}
}
}()
tempJournal, err := makeMdIDJournal(j.codec, journalTempDir)
if err != nil {
return err
}
var prevID kbfsmd.ID
isPendingLocalSquash := bid == kbfsmd.PendingLocalSquashBranchID
for _, entry := range allEntries {
brmd, _, ts, err := j.getMDAndExtra(ctx, entry, true)
if err != nil {
return err
}
if entry.IsLocalSquash && isPendingLocalSquash {
// If this is a local squash, don't convert it. We don't
// want to squash anything more into it.
j.log.CDebugf(ctx, "Preserving local squash %s", entry.ID)
err = tempJournal.append(brmd.RevisionNumber(), entry)
if err != nil {
return err
}
continue
}
brmd.SetUnmerged()
brmd.SetBranchID(bid)
// Re-sign the writer metadata internally, since we
// changed it.
err = brmd.SignWriterMetadataInternally(ctx, j.codec, signer)
if err != nil {
j.log.CDebugf(ctx, "Early exit %d %+v", brmd.RevisionNumber(), err)
return err
}
// Set the prev root for everything after the first MD we
// modify, which happens to be indicated by mdsToRemove being
// non-empty.
if len(mdsToRemove) > 0 {
j.log.CDebugf(ctx, "Old prev root of rev=%s is %s",
brmd.RevisionNumber(), brmd.GetPrevRoot())
j.log.CDebugf(ctx, "Changing prev root of rev=%s to %s",
brmd.RevisionNumber(), prevID)
brmd.SetPrevRoot(prevID)
}
// TODO: this rewrites the file, and so the modification time
// no longer tracks when exactly the original operation is
// done, so future ImmutableBareMetadatas for this MD will
// have a slightly wrong localTimestamp. Instead, we might
// want to pass in the timestamp and do an explicit
// os.Chtimes() on the file after writing it.
newID, err := j.putMD(brmd)
if err != nil {
return err
}
mdsToRemove = append(mdsToRemove, newID)
// Preserve unknown fields from the old journal.
newEntry := entry
newEntry.ID = newID
newEntry.IsLocalSquash = false
err = tempJournal.append(brmd.RevisionNumber(), newEntry)
if err != nil {
return err
}
prevID = newID
// If possible, replace the old RMD in the cache. If it's not
// already in the cache, don't bother adding it, as that will
// just evict something incorrectly. If it's been replaced by
// the REAL commit from the master branch due to a race, don't
// clobber that real commit. TODO: Don't replace the MD until
// we know for sure that the branch conversion succeeds
// (however, the Replace doesn't affect correctness since the
// original commit will be read from disk instead of the cache
// in the event of a conversion failure).
oldIrmd, err := mdcache.Get(
tlfID, brmd.RevisionNumber(), kbfsmd.NullBranchID)
if err == nil && entry.ID == oldIrmd.mdID {
newRmd, err := oldIrmd.deepCopy(codec)
if err != nil {
return err
}
newRmd.bareMd = brmd
// Everything else is the same.
err = mdcache.Replace(
MakeImmutableRootMetadata(newRmd,
oldIrmd.LastModifyingWriterVerifyingKey(),
newID, ts, false),
kbfsmd.NullBranchID)
if err != nil {
return err
}
} else {
j.log.CDebugf(ctx,
"Not cache-replacing rev=%d: old ID=%s, entry.ID=%s, err=%+v",
brmd.RevisionNumber(), oldIrmd.mdID, entry.ID, err)
}
j.log.CDebugf(ctx, "Changing ID for rev=%s from %s to %s",
brmd.RevisionNumber(), entry.ID, newID)
}
// TODO: Do the below atomically on the filesystem
// level. Specifically, make "md_journal" always be a symlink,
// and then perform the swap by atomically changing the
// symlink to point to the new journal directory.
oldJournalTempDir := journalTempDir + ".old"
dir, err := j.j.move(oldJournalTempDir)
if err != nil {
return err
}
j.log.CDebugf(ctx, "Moved old journal from %s to %s",
dir, oldJournalTempDir)
newJournalOldDir, err := tempJournal.move(dir)
if err != nil {
return err
}
j.log.CDebugf(ctx, "Moved new journal from %s to %s",
newJournalOldDir, dir)
// Make the defer block above remove oldJournalTempDir.
journalTempDir = oldJournalTempDir
mdsToRemove = make([]kbfsmd.ID, 0, len(allEntries))
for _, entry := range allEntries {
if entry.IsLocalSquash && isPendingLocalSquash {
continue
}
mdsToRemove = append(mdsToRemove, entry.ID)
}
j.j = tempJournal
j.branchID = bid
return nil
}
// getNextEntryToFlush returns the info for the next journal entry to
// flush, if it exists, and its revision is less than end. If there is
// no next journal entry to flush, the returned MdID will be zero, and
// the returned *RootMetadataSigned will be nil.
func (j mdJournal) getNextEntryToFlush(
ctx context.Context, end kbfsmd.Revision, signer kbfscrypto.Signer) (
kbfsmd.ID, *RootMetadataSigned, kbfsmd.ExtraMetadata, error) {
mdID, rmd, extra, timestamp, err := j.getEarliestWithExtra(ctx, true)
if err != nil {
return kbfsmd.ID{}, nil, nil, err
}
if rmd == nil || rmd.RevisionNumber() >= end {
return kbfsmd.ID{}, nil, nil, nil
}
rmds, err := SignBareRootMetadata(
ctx, j.codec, signer, signer, rmd, timestamp)
if err != nil {
return kbfsmd.ID{}, nil, nil, err
}
return mdID, rmds, extra, nil
}
func (j *mdJournal) removeFlushedEntry(
ctx context.Context, mdID kbfsmd.ID, rmds *RootMetadataSigned) (
clearedMDJournal bool, err error) {
rmdID, rmd, _, _, err := j.getEarliestWithExtra(ctx, true)
if err != nil {
return false, err
}
if rmd == nil {
return false, errors.New("mdJournal unexpectedly empty")
}
if mdID != rmdID {
return false, errors.Errorf("Expected mdID %s, got %s", mdID, rmdID)
}
eq, err := kbfscodec.Equal(j.codec, rmd, rmds.MD)
if err != nil {
return false, err
}
if !eq {
return false, errors.New(
"Given RootMetadataSigned doesn't match earliest")
}
empty, err := j.j.removeEarliest()
if err != nil {
return false, err
}
// Since the journal is now empty, set lastMdID and nuke all
// MD-related directories.
if empty {
j.log.CDebugf(ctx,
"MD journal is now empty; saving last MdID=%s", mdID)
j.lastMdID = mdID
// The disk journal has already been cleared, so we
// can nuke the directories without having to worry
// about putting the journal in a weird state if we
// crash in the middle. The various directories will
// be recreated as needed.
for _, dir := range j.mdJournalDirs() {
j.log.CDebugf(ctx, "Removing all files in %s", dir)
err := ioutil.RemoveAll(dir)
if err != nil {
return false, err
}
}
return true, nil
}
// Garbage-collect the old entry. If we crash here and
// leave behind an entry, it'll be cleaned up the next
// time the journal is completely drained.
err = j.removeMD(mdID)
if err != nil {
return false, err
}
return false, nil
}
func getMdID(ctx context.Context, mdserver MDServer, codec kbfscodec.Codec,
tlfID tlf.ID, bid kbfsmd.BranchID, mStatus kbfsmd.MergeStatus,
revision kbfsmd.Revision, lockBeforeGet *keybase1.LockID) (kbfsmd.ID, error) {
rmdses, err := mdserver.GetRange(
ctx, tlfID, bid, mStatus, revision, revision, lockBeforeGet)
if err != nil {
return kbfsmd.ID{}, err
} else if len(rmdses) == 0 {
return kbfsmd.ID{}, nil
} else if len(rmdses) > 1 {
return kbfsmd.ID{}, errors.Errorf(
"Got more than one object when trying to get rev=%d for branch %s of TLF %s",
revision, bid, tlfID)
}
return kbfsmd.MakeID(codec, rmdses[0].MD)
}
// clearHelper removes all the journal entries starting from
// earliestBranchRevision and deletes the corresponding MD
// updates. All MDs from earliestBranchRevision onwards must have
// branch equal to the given one, which must not be kbfsmd.NullBranchID. This
// means that, if bid != kbfsmd.PendingLocalSquashBranchID,
// earliestBranchRevision must equal the earliest revision, and if bid
// == kbfsmd.PendingLocalSquashBranchID, earliestBranchRevision must equal
// one past the last local squash revision. If the branch is a pending
// local squash, it preserves the MD updates corresponding to the
// prefix of existing local squashes, so they can be re-used in the
// newly-resolved journal.
func (j *mdJournal) clearHelper(ctx context.Context, bid kbfsmd.BranchID,
earliestBranchRevision kbfsmd.Revision) (err error) {
j.log.CDebugf(ctx, "Clearing journal for branch %s", bid)
defer func() {
if err != nil {
j.deferLog.CDebugf(ctx,
"Clearing journal for branch %s failed with %+v",
bid, err)
}
}()
if bid == kbfsmd.NullBranchID {
return errors.New("Cannot clear master branch")
}
if j.branchID != bid {
// Nothing to do.
j.log.CDebugf(ctx, "Ignoring clear for branch %s while on branch %s",
bid, j.branchID)
return nil
}
head, err := j.getHead(ctx, bid)
if err != nil {
return err
}
if head == (ImmutableBareRootMetadata{}) {
// The journal has been flushed but not cleared yet.
j.branchID = kbfsmd.NullBranchID
return nil
}
if head.BID() != j.branchID {
return errors.Errorf("Head branch ID %s doesn't match journal "+
"branch ID %s while clearing", head.BID(), j.branchID)
}
latestRevision, err := j.j.readLatestRevision()
if err != nil {
return err
}
_, allEntries, err := j.j.getEntryRange(
earliestBranchRevision, latestRevision)
if err != nil {
return err
}
err = j.j.clearFrom(earliestBranchRevision)
if err != nil {
return err
}
j.branchID = kbfsmd.NullBranchID
// No need to set lastMdID in this case.