From bd18960cb93f3b6e9f43f3cabec34f1929f05ec3 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon, 11 Sep 2017 22:02:58 -0400
Subject: [PATCH] Fix RecursiveCopy.pm to cope with disappearing files.
When copying from an active database tree, it's possible for files to be
deleted after we see them in a readdir() scan but before we can open them.
(Once we've got a file open, we don't expect any further errors from it
getting unlinked, though.) Tweak RecursiveCopy so it can cope with this
case, so as to avoid irreproducible test failures.
Back-patch to 9.6 where this code was added. In v10 and HEAD, also
remove unused "use RecursiveCopy" in one recovery test script.
Michael Paquier and Tom Lane
Discussion: https://postgr.es/m/24621.1504924323@sss.pgh.pa.us
---
src/test/perl/RecursiveCopy.pm | 64 +++++++++++++------
.../t/010_logical_decoding_timelines.pl | 1 -
2 files changed, 45 insertions(+), 20 deletions(-)
diff --git a/src/test/perl/RecursiveCopy.pm b/src/test/perl/RecursiveCopy.pm
index 28ecaf6db23..19f7dd2fffe 100644
--- a/src/test/perl/RecursiveCopy.pm
+++ b/src/test/perl/RecursiveCopy.pm
@@ -29,12 +29,17 @@ use File::Copy;
=head2 copypath($from, $to, %params)
Recursively copy all files and directories from $from to $to.
+Does not preserve file metadata (e.g., permissions).
Only regular files and subdirectories are copied. Trying to copy other types
of directory entries raises an exception.
Raises an exception if a file would be overwritten, the source directory can't
-be read, or any I/O operation fails. Always returns true.
+be read, or any I/O operation fails. However, we silently ignore ENOENT on
+open, because when copying from a live database it's possible for a file/dir
+to be deleted after we see its directory entry but before we can open it.
+
+Always returns true.
If the B<filterfn> parameter is given, it must be a subroutine reference.
This subroutine will be called for each entry in the source directory with its
@@ -74,6 +79,9 @@ sub copypath
$filterfn = sub { return 1; };
}
+ # Complain if original path is bogus, because _copypath_recurse won't.
+ die "\"$base_src_dir\" does not exist" if !-e $base_src_dir;
+
# Start recursive copy from current directory
return _copypath_recurse($base_src_dir, $base_dest_dir, "", $filterfn);
}
@@ -89,12 +97,8 @@ sub _copypath_recurse
return 1 unless &$filterfn($curr_path);
# Check for symlink -- needed only on source dir
- die "Cannot operate on symlinks" if -l $srcpath;
-
- # Can't handle symlinks or other weird things
- die "Source path \"$srcpath\" is not a regular file or directory"
- unless -f $srcpath
- or -d $srcpath;
+ # (note: this will fall through quietly if file is already gone)
+ die "Cannot operate on symlink \"$srcpath\"" if -l $srcpath;
# Abort if destination path already exists. Should we allow directories
# to exist already?
@@ -104,25 +108,47 @@ sub _copypath_recurse
# same name and we're done.
if (-f $srcpath)
{
- copy($srcpath, $destpath)
+ my $fh;
+ unless (open($fh, '<', $srcpath))
+ {
+ return 1 if ($!{ENOENT});
+ die "open($srcpath) failed: $!";
+ }
+ copy($fh, $destpath)
or die "copy $srcpath -> $destpath failed: $!";
+ close $fh;
return 1;
}
- # Otherwise this is directory: create it on dest and recurse onto it.
- mkdir($destpath) or die "mkdir($destpath) failed: $!";
-
- opendir(my $directory, $srcpath) or die "could not opendir($srcpath): $!";
- while (my $entry = readdir($directory))
+ # If it's a directory, create it on dest and recurse into it.
+ if (-d $srcpath)
{
- next if ($entry eq '.' or $entry eq '..');
- _copypath_recurse($base_src_dir, $base_dest_dir,
- $curr_path eq '' ? $entry : "$curr_path/$entry", $filterfn)
- or die "copypath $srcpath/$entry -> $destpath/$entry failed";
+ my $directory;
+ unless (opendir($directory, $srcpath))
+ {
+ return 1 if ($!{ENOENT});
+ die "opendir($srcpath) failed: $!";
+ }
+
+ mkdir($destpath) or die "mkdir($destpath) failed: $!";
+
+ while (my $entry = readdir($directory))
+ {
+ next if ($entry eq '.' or $entry eq '..');
+ _copypath_recurse($base_src_dir, $base_dest_dir,
+ $curr_path eq '' ? $entry : "$curr_path/$entry", $filterfn)
+ or die "copypath $srcpath/$entry -> $destpath/$entry failed";
+ }
+
+ closedir($directory);
+ return 1;
}
- closedir($directory);
- return 1;
+ # If it disappeared from sight, that's OK.
+ return 1 if !-e $srcpath;
+
+ # Else it's some weird file type; complain.
+ die "Source path \"$srcpath\" is not a regular file or directory";
}
1;
diff --git a/src/test/recovery/t/010_logical_decoding_timelines.pl b/src/test/recovery/t/010_logical_decoding_timelines.pl
index edc0219c9cd..5620450acfe 100644
--- a/src/test/recovery/t/010_logical_decoding_timelines.pl
+++ b/src/test/recovery/t/010_logical_decoding_timelines.pl
@@ -24,7 +24,6 @@ use warnings;
use PostgresNode;
use TestLib;
use Test::More tests => 13;
-use RecursiveCopy;
use File::Copy;
use IPC::Run ();
use Scalar::Util qw(blessed);
--
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