From 75f317eaf1d7cc458e8bf0ef7a6030e530a007f0 Mon Sep 17 00:00:00 2001
From: Michael Eischer <michael.eischer@fau.de>
Date: Mon, 21 Oct 2024 21:41:56 +0200
Subject: [PATCH] sftp: check for broken connection in Load/List operation

---
 changelog/unreleased/pull-5101 | 9 +++++++++
 internal/backend/sftp/sftp.go  | 8 ++++++++
 2 files changed, 17 insertions(+)
 create mode 100644 changelog/unreleased/pull-5101

diff --git a/changelog/unreleased/pull-5101 b/changelog/unreleased/pull-5101
new file mode 100644
index 000000000..f784d0c47
--- /dev/null
+++ b/changelog/unreleased/pull-5101
@@ -0,0 +1,9 @@
+Bugfix: Do not retry load/list operation is SFTP connection is broken
+
+When using restic with the SFTP backend, backend operations that load
+a file or list files were retried even if the SFTP connection is broken.
+
+This has been fixed now.
+
+https://github.com/restic/restic/pull/5101
+https://forum.restic.net/t/restic-hanging-on-backup/8559/2
diff --git a/internal/backend/sftp/sftp.go b/internal/backend/sftp/sftp.go
index efbd0c8d5..6b9620a36 100644
--- a/internal/backend/sftp/sftp.go
+++ b/internal/backend/sftp/sftp.go
@@ -421,6 +421,10 @@ func (r *SFTP) checkNoSpace(dir string, size int64, origErr error) error {
 // Load runs fn with a reader that yields the contents of the file at h at the
 // given offset.
 func (r *SFTP) Load(ctx context.Context, h backend.Handle, length int, offset int64, fn func(rd io.Reader) error) error {
+	if err := r.clientError(); err != nil {
+		return err
+	}
+
 	return util.DefaultLoad(ctx, h, length, offset, r.openReader, func(rd io.Reader) error {
 		if length == 0 || !feature.Flag.Enabled(feature.BackendErrorRedesign) {
 			return fn(rd)
@@ -490,6 +494,10 @@ func (r *SFTP) Remove(_ context.Context, h backend.Handle) error {
 // List runs fn for each file in the backend which has the type t. When an
 // error occurs (or fn returns an error), List stops and returns it.
 func (r *SFTP) List(ctx context.Context, t backend.FileType, fn func(backend.FileInfo) error) error {
+	if err := r.clientError(); err != nil {
+		return err
+	}
+
 	basedir, subdirs := r.Basedir(t)
 	walker := r.c.Walk(basedir)
 	for {