From: Matt Joiner <anacrolix@gmail.com>
Date: Mon, 22 Feb 2021 05:39:21 +0000 (+1100)
Subject: Add missing closeMu use in ReadConsecutiveChunks
X-Git-Tag: v1.26.0-alpha~5
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=f00f51370627b385edf01bf67c1c5261a9fa70d0;p=btrtrc.git

Add missing closeMu use in ReadConsecutiveChunks
---

diff --git a/storage/sqlite/sqlite-storage.go b/storage/sqlite/sqlite-storage.go
index 1eb4b0fe..4b5abb24 100644
--- a/storage/sqlite/sqlite-storage.go
+++ b/storage/sqlite/sqlite-storage.go
@@ -367,12 +367,15 @@ type provider struct {
 var _ storage.ConsecutiveChunkReader = (*provider)(nil)
 
 func (p *provider) ReadConsecutiveChunks(prefix string) (io.ReadCloser, error) {
+	p.closeMu.RLock()
 	runner, err := p.getReadWithConnRunner()
 	if err != nil {
+		p.closeMu.RUnlock()
 		return nil, err
 	}
 	r, w := io.Pipe()
 	go func() {
+		defer p.closeMu.RUnlock()
 		err = runner(func(_ context.Context, conn conn) error {
 			var written int64
 			err = sqlitex.Exec(conn, `
@@ -506,6 +509,8 @@ func getLabels(skip int) pprof.LabelSet {
 
 func (p *provider) withConn(with withConn, write bool, skip int) error {
 	p.closeMu.RLock()
+	// I think we need to check this here because it may not be valid to send to the writes channel
+	// if we're already closed. So don't try to move this check into getReadWithConnRunner.
 	if p.closed {
 		p.closeMu.RUnlock()
 		return errors.New("closed")
@@ -530,7 +535,8 @@ func (p *provider) withConn(with withConn, write bool, skip int) error {
 }
 
 // Obtains a DB conn and returns a withConn for executing with it. If no error is returned from this
-// function, the runner *must* be used or the conn is leaked.
+// function, the runner *must* be used or the conn is leaked. You should check the provider isn't
+// closed before using this.
 func (p *provider) getReadWithConnRunner() (with func(withConn) error, err error) {
 	conn := p.pool.Get(context.TODO())
 	if conn == nil {