14398: Fix deadlock on error in GetCurrentState.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tclegg@veritasgenetics.com>

diff --git a/services/keep-balance/balance.go b/services/keep-balance/balance.go
index 5f5f9afdc4741d6c8b74fb582f52a706fd5ea9be..8b4924f0aaba517f3920bd474b20decff0483ff0 100644 (file)
--- a/services/keep-balance/balance.go
+++ b/services/keep-balance/balance.go
@@ -263,7 +263,7 @@ func (bal *Balancer) GetCurrentState(c *arvados.Client, pageSize, bufs int) erro
        bal.DefaultReplication = dd.DefaultCollectionReplication
        bal.MinMtime = time.Now().UnixNano() - dd.BlobSignatureTTL*1e9
 
-       errs := make(chan error, 2+len(bal.KeepServices))
+       errs := make(chan error, 1)
        wg := sync.WaitGroup{}
 
        // When a device is mounted more than once, we will get its
@@ -298,7 +298,10 @@ func (bal *Balancer) GetCurrentState(c *arvados.Client, pageSize, bufs int) erro
                        bal.logf("mount %s: retrieve index from %s", mounts[0], mounts[0].KeepService)
                        idx, err := mounts[0].KeepService.IndexMount(c, mounts[0].UUID, "")
                        if err != nil {
-                               errs <- fmt.Errorf("%s: retrieve index: %v", mounts[0], err)
+                               select {
+                               case errs <- fmt.Errorf("%s: retrieve index: %v", mounts[0], err):
+                               default:
+                               }
                                return
                        }
                        if len(errs) > 0 {
@@ -330,7 +333,10 @@ func (bal *Balancer) GetCurrentState(c *arvados.Client, pageSize, bufs int) erro
                for coll := range collQ {
                        err := bal.addCollection(coll)
                        if err != nil {
-                               errs <- err
+                               select {
+                               case errs <- err:
+                               default:
+                               }
                                for range collQ {
                                }
                                return
@@ -360,7 +366,10 @@ func (bal *Balancer) GetCurrentState(c *arvados.Client, pageSize, bufs int) erro
                        })
                close(collQ)
                if err != nil {
-                       errs <- err
+                       select {
+                       case errs <- err:
+                       default:
+                       }
                }
        }()