From b218d3f5d8ff772e2b98a044bfe97791d3b02f53 Mon Sep 17 00:00:00 2001
From: "David T. Crosby" <dtcrsby@gmail.com>
Date: Tue, 13 Aug 2024 14:06:39 -0600
Subject: [PATCH] [#1830] Check that sysfs directory exists before reading
 (#1831)

Signed-off-by: David Crosby <dcrosby@fb.com>
---
 lib/ohai/plugins/filesystem.rb             | 26 ++++++++++++----------
 spec/unit/plugins/linux/filesystem_spec.rb |  1 +
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/lib/ohai/plugins/filesystem.rb b/lib/ohai/plugins/filesystem.rb
index f6cb6a2b6..a97fb7231 100644
--- a/lib/ohai/plugins/filesystem.rb
+++ b/lib/ohai/plugins/filesystem.rb
@@ -276,19 +276,21 @@ def collect_btrfs_data(entry)
     if entry[:fs_type] == "btrfs" && entry["uuid"]
       uuid = entry["uuid"]
       alloc = "/sys/fs/btrfs/#{uuid}/allocation"
-      %w{data metadata system}.each do |bg_type|
-        dir = "#{alloc}/#{bg_type}"
-        %w{single dup}.each do |raid|
-          if file_exist?("#{dir}/#{raid}")
-            btrfs["raid"] = raid
+      if Dir.exist?(alloc)
+        %w{data metadata system}.each do |bg_type|
+          dir = "#{alloc}/#{bg_type}"
+          %w{single dup}.each do |raid|
+            if file_exist?("#{dir}/#{raid}")
+              btrfs["raid"] = raid
+            end
+          end
+          logger.trace("Plugin Filesystem: reading btrfs allocation files at #{dir}")
+          btrfs["allocation"] ||= Mash.new
+          btrfs["allocation"][bg_type] ||= Mash.new
+          %w{total_bytes bytes_used}.each do |field|
+            bytes = file_read("#{dir}/#{field}").chomp.to_i
+            btrfs["allocation"][bg_type][field] = "#{bytes}"
           end
-        end
-        logger.trace("Plugin Filesystem: reading btrfs allocation files at #{dir}")
-        btrfs["allocation"] ||= Mash.new
-        btrfs["allocation"][bg_type] ||= Mash.new
-        %w{total_bytes bytes_used}.each do |field|
-          bytes = file_read("#{dir}/#{field}").chomp.to_i
-          btrfs["allocation"][bg_type][field] = "#{bytes}"
         end
       end
     end
diff --git a/spec/unit/plugins/linux/filesystem_spec.rb b/spec/unit/plugins/linux/filesystem_spec.rb
index 1cbbe4469..dac141878 100644
--- a/spec/unit/plugins/linux/filesystem_spec.rb
+++ b/spec/unit/plugins/linux/filesystem_spec.rb
@@ -72,6 +72,7 @@
 
     btrfs_sysfs_base = "/sys/fs/btrfs/d6efda02-1b73-453c-8c74-7d8dee78fa5e/allocation"
     %w{data metadata system}.each do |bg_type|
+      allow(Dir).to receive(:exist?).with(btrfs_sysfs_base).and_return(true)
       allow(File).to receive(:exist?).with("#{btrfs_sysfs_base}/#{bg_type}/single").and_return(true)
       allow(File).to receive(:exist?).with("#{btrfs_sysfs_base}/#{bg_type}/dup").and_return(false)
       %w{total_bytes bytes_used}.each do |field|