From c76239b1d40df4aead0dd9f04f8161cc17d8f4cd Mon Sep 17 00:00:00 2001
From: rcourtman <courtmanr@gmail.com>
Date: Wed, 3 Dec 2025 14:06:15 +0000
Subject: [PATCH] fix: Filter container overlay mounts in non-standard
 locations

Detect container overlay filesystem paths from various container runtimes
(Docker, Podman, LXC, EnhanceCP, etc.) that may not be in standard
/var/lib/docker or /var/lib/containers locations.

Paths containing /containers/ with overlay patterns (/overlay2/, /overlay/,
/diff/, /merged) are now filtered from disk usage aggregation.

Related to #790
---
 pkg/fsfilters/filters.go      | 23 +++++++++++++++++++++++
 pkg/fsfilters/filters_test.go |  6 ++++++
 2 files changed, 29 insertions(+)

diff --git a/pkg/fsfilters/filters.go b/pkg/fsfilters/filters.go
index 93f2fc7..8d6b9a4 100644
--- a/pkg/fsfilters/filters.go
+++ b/pkg/fsfilters/filters.go
@@ -86,9 +86,21 @@ var specialMountPrefixes = []string{
 	"/sys",
 	"/run",
 	"/var/lib/docker",
+	"/var/lib/containers",
 	"/snap",
 }
 
+// containerOverlayPatterns detect container overlay filesystem paths from various
+// container runtimes (Docker, Podman, LXC, EnhanceCP, etc.) that may not be in
+// standard locations. These paths should be excluded from disk usage as they
+// represent container layers, not actual storage usage.
+var containerOverlayPatterns = []string{
+	"/overlay2/",
+	"/overlay/",
+	"/diff/",
+	"/merged",
+}
+
 // ShouldSkipFilesystem determines if a filesystem should be excluded from disk
 // usage aggregation. It checks for read-only filesystems, virtual/pseudo filesystems,
 // network mounts, and special system mountpoints. Returns skip=true if the filesystem
@@ -132,5 +144,16 @@ func ShouldSkipFilesystem(fsType, mountpoint string, totalBytes, usedBytes uint6
 		reasons = append(reasons, "special-mountpoint")
 	}
 
+	// Check for container overlay paths from various runtimes in non-standard locations
+	// (e.g., /var/local/enhance/containers/*/overlay/merged). Related to #790.
+	if strings.Contains(mountpoint, "/containers/") {
+		for _, pattern := range containerOverlayPatterns {
+			if strings.Contains(mountpoint, pattern) {
+				reasons = append(reasons, "container-overlay")
+				break
+			}
+		}
+	}
+
 	return len(reasons) > 0, reasons
 }
diff --git a/pkg/fsfilters/filters_test.go b/pkg/fsfilters/filters_test.go
index 7ee28cb..4af2622 100644
--- a/pkg/fsfilters/filters_test.go
+++ b/pkg/fsfilters/filters_test.go
@@ -173,6 +173,12 @@ func TestShouldSkipFilesystem(t *testing.T) {
 		{"/var/lib/docker", "ext4", "/var/lib/docker/overlay2", 1000000, 500000, true},
 		{"/snap prefix", "ext4", "/snap/core/12345", 1000000, 500000, true},
 		{"/boot/efi exact", "vfat", "/boot/efi", 512 * 1024 * 1024, 50 * 1024 * 1024, true},
+		{"/var/lib/containers podman", "ext4", "/var/lib/containers/storage/overlay/abc123/merged", 1000000, 500000, true},
+
+		// Container overlay paths in non-standard locations (issue #790)
+		{"enhance containers overlay", "ext4", "/var/local/enhance/containers/abc123/overlay/merged", 1000000, 500000, true},
+		{"custom containers diff", "ext4", "/opt/containers/myapp/diff/layer", 1000000, 500000, true},
+		{"custom containers overlay2", "ext4", "/data/containers/xyz/overlay2/layer1", 1000000, 500000, true},
 
 		// Windows paths
 		{"Windows System Reserved", "NTFS", "System Reserved", 500 * 1024 * 1024, 100 * 1024 * 1024, true},