rewrite Linux nodatacow use in pure Perl w/o system

btrfs is Linux-only at the moment (and likely to remain that way
for practical purposes).  So rely on Linux ABI stability and use
the `syscall' and `ioctl' perlops rather than relying on Inline::C.
Inline::C (and gcc||clang) are monstrous dependencies which we
can't expect users to have.

This makes supporting new architectures more difficult, but new
architectures come along rarely and this reduces the burden for
the majority of Linux users on popular architectures (while
still avoiding the distribution of pre-built binaries).

Link: https://public-inbox.org/meta/YbCPWGaJEkV6eWfo@codewreck.org/

1 files changed, 6 insertions, 5 deletions

diff --git a/lib/PublicInbox/Xapcmd.pm b/lib/PublicInbox/Xapcmd.pm
index 44e0f8e5..10685636 100644
--- a/lib/PublicInbox/Xapcmd.pm
+++ b/lib/PublicInbox/Xapcmd.pm
@@ -1,8 +1,9 @@
-# Copyright (C) 2018-2021 all contributors <meta@public-inbox.org>
+# Copyright (C) all contributors <meta@public-inbox.org>
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 package PublicInbox::Xapcmd;
 use strict;
-use PublicInbox::Spawn qw(which popen_rd nodatacow_dir);
+use PublicInbox::Spawn qw(which popen_rd);
+use PublicInbox::Syscall;
 use PublicInbox::Admin qw(setup_signals);
 use PublicInbox::Over;
 use PublicInbox::SearchIdx;
@@ -211,7 +212,7 @@ sub prepare_run {
                 my $v = PublicInbox::Search::SCHEMA_VERSION();
                 my $wip = File::Temp->newdir("xapian$v-XXXX", DIR => $dir);
                 $tmp->{$old} = $wip;
-                nodatacow_dir($wip->dirname);
+                PublicInbox::Syscall::nodatacow_dir($wip->dirname);
                 push @queue, [ $old, $wip ];
         } elsif (defined $old) {
                 opendir my $dh, $old or die "Failed to opendir $old: $!\n";
@@ -242,7 +243,7 @@ sub prepare_run {
                         same_fs_or_die($old, $wip->dirname);
                         my $cur = "$old/$dn";
                         push @queue, [ $src // $cur , $wip ];
-                        nodatacow_dir($wip->dirname);
+                        PublicInbox::Syscall::nodatacow_dir($wip->dirname);
                         $tmp->{$cur} = $wip;
                 }
                 # mark old shards to be unlinked
@@ -443,7 +444,7 @@ sub cpdb ($$) { # cb_spawn callback
                 $ft = File::Temp->newdir("$new.compact-XXXX", DIR => $dir);
                 setup_signals();
                 $tmp = $ft->dirname;
-                nodatacow_dir($tmp);
+                PublicInbox::Syscall::nodatacow_dir($tmp);
         } else {
                 $tmp = $new;
         }