pkg/index: make corpus RLock take a context

Also remove extra (deadlocking) RLock in pkg/search.

Updates issue #709

Change-Id: I556a1fbf9217f482b6a51e74c28a019dea8369a2

pkg/index/corpus.go

@@ -44,7 +44,7 @@ import (
 // Corpus is an in-memory summary of all of a user's blobs' metadata.
 type Corpus struct {
 	mu sync.RWMutex
-	//mu syncutil.RWMutexTracker // when debugging
+	// mu syncdebug.RWMutexTracker // when debugging
 
 	// building is true at start while scanning all rows in the
 	// index.  While building, certain invariants (like things
@@ -108,14 +108,14 @@ type latLong struct {
 }
 
 // RLock locks the Corpus for reads. It must be used for any "Locked" methods.
-func (c *Corpus) RLock() { c.mu.RLock() }
+func (c *Corpus) RLock(ctx context.Context) { c.mu.RLock() }
 
 // RUnlock unlocks the Corpus for reads.
 func (c *Corpus) RUnlock() { c.mu.RUnlock() }
 
 // IsDeleted reports whether the provided blobref (of a permanode or claim) should be considered deleted.
-func (c *Corpus) IsDeleted(br blob.Ref) bool {
-	c.RLock()
+func (c *Corpus) IsDeleted(ctx context.Context, br blob.Ref) bool {
+	c.RLock(ctx)
 	defer c.RUnlock()
 	return c.IsDeletedLocked(br)
 }

pkg/index/corpus_test.go

@@ -129,8 +129,9 @@ func TestCorpusAppendPermanodeAttrValues(t *testing.T) {
 
 func TestCorpusPermanodeAttrValueLocked(t *testing.T) {
 	c, pn := newTestCorpusWithPermanode()
+	ctx := context.TODO()
 
-	c.RLock()
+	c.RLock(ctx)
 	defer c.RUnlock()
 
 	tests := []struct {
@@ -174,7 +175,8 @@ func TestCorpusPermanodeAttrValueLocked(t *testing.T) {
 func TestCorpusPermanodeHasAttrValueLocked(t *testing.T) {
 	c, pn := newTestCorpusWithPermanode()
 
-	c.RLock()
+	ctx := context.TODO()
+	c.RLock(ctx)
 	defer c.RUnlock()
 
 	tests := []struct {
@@ -294,7 +296,8 @@ func testDeletePermanodes(t *testing.T,
 	ch := make(chan camtypes.BlobMeta, 10)
 	var got []camtypes.BlobMeta
 	errc := make(chan error, 1)
-	c.RLock()
+	ctx := context.TODO()
+	c.RLock(ctx)
 	go func() { errc <- enumFunc(c, context.TODO(), ch) }()
 	for blobMeta := range ch {
 		got = append(got, blobMeta)
@@ -325,7 +328,7 @@ func testDeletePermanodes(t *testing.T,
 	want = []blob.Ref{foopn}
 	got = got[:0]
 	ch = make(chan camtypes.BlobMeta, 10)
-	c.RLock()
+	c.RLock(ctx)
 	go func() { errc <- enumFunc(c, context.TODO(), ch) }()
 	for blobMeta := range ch {
 		got = append(got, blobMeta)
@@ -347,7 +350,7 @@ func testDeletePermanodes(t *testing.T,
 	want = []blob.Ref{foopn, bazpn}
 	got = got[:0]
 	ch = make(chan camtypes.BlobMeta, 10)
-	c.RLock()
+	c.RLock(ctx)
 	go func() { errc <- enumFunc(c, context.TODO(), ch) }()
 	for blobMeta := range ch {
 		got = append(got, blobMeta)
@@ -432,7 +435,8 @@ func testEnumerateOrder(t *testing.T,
 	ch := make(chan camtypes.BlobMeta, 10)
 	var got []camtypes.BlobMeta
 	errc := make(chan error, 1)
-	c.RLock()
+	ctx := context.TODO()
+	c.RLock(ctx)
 	go func() { errc <- enumFunc(c, context.TODO(), ch) }()
 	for blobMeta := range ch {
 		got = append(got, blobMeta)
@@ -488,11 +492,12 @@ func testCacheSortedPermanodesRace(t *testing.T,
 		}
 		donec <- struct{}{}
 	}()
+	ctx := context.TODO()
 	go func() {
 		for i := 0; i < 10; i++ {
 			ch := make(chan camtypes.BlobMeta, 10)
 			errc := make(chan error, 1)
-			c.RLock()
+			c.RLock(ctx)
 			go func() { errc <- enumFunc(c, context.TODO(), ch) }()
 			for range ch {
 			}
@@ -528,7 +533,8 @@ func TestLazySortedPermanodes(t *testing.T) {
 	enum := func(reverse bool) {
 		ch := make(chan camtypes.BlobMeta, 10)
 		errc := make(chan error, 1)
-		c.RLock()
+		ctx := context.TODO()
+		c.RLock(ctx)
 		go func() { errc <- c.EnumeratePermanodesCreatedLocked(context.TODO(), ch, reverse) }()
 		for range ch {
 		}

pkg/index/index.go

@@ -1393,7 +1393,7 @@ func enumerateBlobMeta(s sorted.KeyValue, cb func(camtypes.BlobMeta) error) (err
 // EnumerateBlobMeta sends all metadata about all known blobs to ch and then closes ch.
 func (x *Index) EnumerateBlobMeta(ctx context.Context, ch chan<- camtypes.BlobMeta) (err error) {
 	if x.corpus != nil {
-		x.corpus.RLock()
+		x.corpus.RLock(ctx)
 		defer x.corpus.RUnlock()
 		return x.corpus.EnumerateBlobMetaLocked(ctx, ch)
 	}

pkg/search/query.go

@@ -857,7 +857,7 @@ func (h *Handler) Query(rawq *SearchQuery) (*SearchResult, error) {
 	corpus := h.corpus
 	var unlockOnce sync.Once
 	if corpus != nil {
-		corpus.RLock()
+		corpus.RLock(ctx)
 		defer unlockOnce.Do(corpus.RUnlock)
 	}
 
@@ -943,7 +943,6 @@ func (h *Handler) Query(rawq *SearchQuery) (*SearchResult, error) {
 				return nil, errors.New("TODO: Sorting without a corpus unsupported")
 			}
 			var err error
-			corpus.RLock()
 			sort.Sort(sortSearchResultBlobs{res.Blobs, func(a, b *SearchResultBlob) bool {
 				if err != nil {
 					return false
@@ -963,7 +962,6 @@ func (h *Handler) Query(rawq *SearchQuery) (*SearchResult, error) {
 				}
 				return tb.Before(ta)
 			}})
-			corpus.RUnlock()
 			if err != nil {
 				return nil, err
 			}