18376: Retry up to 4 times on EBADCOOKIE from readdir.

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tom@curii.com>

diff --git a/services/keepstore/unix_volume.go b/services/keepstore/unix_volume.go
index 46f4db4095bfb286c82f4f07a988c16cee5ebe63..a053ba3e6b19042c48423cf31303e8cc2059fa1d 100644 (file)
--- a/services/keepstore/unix_volume.go
+++ b/services/keepstore/unix_volume.go
@@ -379,23 +379,25 @@ func (v *UnixVolume) IndexTo(prefix string, w io.Writer) error {
                        continue
                }
                blockdirpath := filepath.Join(v.Root, subdir)
-               blockdir, err := v.os.Open(blockdirpath)
-               if err != nil {
-                       v.logger.WithError(err).Errorf("error reading %q", blockdirpath)
-                       return fmt.Errorf("error reading %q: %s", blockdirpath, err)
-               }
-               v.os.stats.TickOps("readdir")
-               v.os.stats.Tick(&v.os.stats.ReaddirOps)
-               // ReadDir() (compared to Readdir(), which returns
-               // FileInfo structs) helps complete the sequence of
-               // readdirent calls as quickly as possible, reducing
-               // the likelihood of NFS EBADCOOKIE (523) errors.
-               dirents, err := blockdir.ReadDir(-1)
-               blockdir.Close()
-               if err != nil {
-                       v.logger.WithError(err).Errorf("error reading %q", blockdirpath)
-                       return fmt.Errorf("error reading %q: %s", blockdirpath, err)
+
+               var dirents []os.DirEntry
+               for attempt := 0; ; attempt++ {
+                       v.os.stats.TickOps("readdir")
+                       v.os.stats.Tick(&v.os.stats.ReaddirOps)
+                       dirents, err = os.ReadDir(blockdirpath)
+                       if err == nil {
+                               break
+                       } else if attempt < 5 && strings.Contains(err.Error(), "errno 523") {
+                               // EBADCOOKIE (NFS stopped accepting
+                               // our readdirent cookie) -- retry a
+                               // few times before giving up
+                               v.logger.WithError(err).Printf("retry after error reading %s", blockdirpath)
+                               continue
+                       } else {
+                               return err
+                       }
                }
+
                for _, dirent := range dirents {
                        fileInfo, err := dirent.Info()
                        if os.IsNotExist(err) {