From d0f1060df74d3c88ebc26c83924ae5e13ab6408b Mon Sep 17 00:00:00 2001
From: DRON-666 <64691982+DRON-666@users.noreply.github.com>
Date: Tue, 30 Aug 2022 04:38:17 +0300
Subject: [PATCH 1/2] Fix quadratic time complexity of Snapshot.HasPaths

---
 internal/restic/snapshot.go | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/internal/restic/snapshot.go b/internal/restic/snapshot.go
index 10c4f218e..9eb7ab3ab 100644
--- a/internal/restic/snapshot.go
+++ b/internal/restic/snapshot.go
@@ -237,19 +237,14 @@ func (sn *Snapshot) HasTagList(l []TagList) bool {
 	return false
 }
 
-func (sn *Snapshot) hasPath(path string) bool {
-	for _, snPath := range sn.Paths {
-		if path == snPath {
-			return true
-		}
-	}
-	return false
-}
-
 // HasPaths returns true if the snapshot has all of the paths.
 func (sn *Snapshot) HasPaths(paths []string) bool {
+	m := make(map[string]struct{}, len(sn.Paths))
+	for _, snPath := range sn.Paths {
+		m[snPath] = struct{}{}
+	}
 	for _, path := range paths {
-		if !sn.hasPath(path) {
+		if _, ok := m[path]; !ok {
 			return false
 		}
 	}

From 2a630c51c1f87838afaab115f3b68f0072f643ff Mon Sep 17 00:00:00 2001
From: DRON-666 <64691982+DRON-666@users.noreply.github.com>
Date: Tue, 30 Aug 2022 04:52:24 +0300
Subject: [PATCH 2/2] Add changelog

---
 changelog/unreleased/pull-3905 | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 changelog/unreleased/pull-3905

diff --git a/changelog/unreleased/pull-3905 b/changelog/unreleased/pull-3905
new file mode 100644
index 000000000..f9d55da6e
--- /dev/null
+++ b/changelog/unreleased/pull-3905
@@ -0,0 +1,6 @@
+Enhancement: Improve speed of parent snapshot searching for `backup` command
+
+Backing up a large number of files using `--files-from-verbatim` or `--files-from-raw`
+options could require a long time to find the parent snapshot. This has been improved.
+
+https://github.com/restic/restic/pull/3905