1 files changed, 29 insertions, 0 deletions
diff --git a/lib/PublicInbox/NDC_PP.pm b/lib/PublicInbox/NDC_PP.pm
new file mode 100644
index 00000000..0d20030d
--- /dev/null
+++ b/lib/PublicInbox/NDC_PP.pm
@@ -0,0 +1,29 @@
+# Copyright (C) 2020 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+
+# Pure-perl class for Linux non-Inline::C users to disable COW for btrfs
+package PublicInbox::NDC_PP;
+use strict;
+use v5.10.1;
+
+sub set_nodatacow ($) {
+        my ($fd) = @_;
+        return if $^O ne 'linux';
+        defined(my $path = readlink("/proc/self/fd/$fd")) or return;
+        open my $mh, '<', '/proc/self/mounts' or return;
+        for (grep(/ btrfs /, <$mh>)) {
+                my (undef, $mnt_path, $type) = split(/ /);
+                next if $type ne 'btrfs'; # in case of false-positive from grep
+
+                # weird chars are escaped as octal
+                $mnt_path =~ s/\\(0[0-9]{2})/chr(oct($1))/egs;
+                $mnt_path .= '/' unless $mnt_path =~ m!/\z!;
+                if (index($path, $mnt_path) == 0) {
+                        # error goes to stderr, but non-fatal for us
+                        system('chattr', '+C', $path);
+                        last;
+                }
+        }
+}
+
+1;