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authorJunio C Hamano <junkio@cox.net>2007-02-21 05:54:39 (GMT)
committerJunio C Hamano <junkio@cox.net>2007-02-27 23:44:40 (GMT)
commitada5ef3b48be7ded62af1f9b7fdb71db3024ac71 (patch)
treef9ebafa7ae1dd97f011e374b2c4d41862cef562f /git-cvsserver.perl
parent4e4b55dd0f5b4644767265f7c16a8b370278ce56 (diff)
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Make 'cvs ci' lockless in git-cvsserver by using git-update-ref
This makes "ci" codepath lockless by following the usual "remember the tip, do your thing, then compare and swap at the end" update pattern using update-ref. Incidentally, by updating the code that reads where the tip of the head is to use show-ref, it makes it safe to use in a repository whose refs are pack-pruned. I noticed that other parts of the program are not yet pack-refs safe, but tried to keep the changes to the minimum. Signed-off-by: Junio C Hamano <junkio@cox.net>
Diffstat (limited to 'git-cvsserver.perl')
-rwxr-xr-xgit-cvsserver.perl43
1 files changed, 16 insertions, 27 deletions
diff --git a/git-cvsserver.perl b/git-cvsserver.perl
index 84520e7..8e12f81 100755
--- a/git-cvsserver.perl
+++ b/git-cvsserver.perl
@@ -1031,36 +1031,35 @@ sub req_ci
exit;
}
- my $lockfile = "$state->{CVSROOT}/refs/heads/$state->{module}.lock";
- unless ( sysopen(LOCKFILE,$lockfile,O_EXCL|O_CREAT|O_WRONLY) )
- {
- $log->warn("lockfile '$lockfile' already exists, please try again");
- print "error 1 Lock file '$lockfile' already exists, please try again\n";
- exit;
- }
-
# Grab a handle to the SQLite db and do any necessary updates
my $updater = GITCVS::updater->new($state->{CVSROOT}, $state->{module}, $log);
$updater->update();
my $tmpdir = tempdir ( DIR => $TEMP_DIR );
my ( undef, $file_index ) = tempfile ( DIR => $TEMP_DIR, OPEN => 0 );
- $log->info("Lock successful, basing commit on '$tmpdir', index file is '$file_index'");
+ $log->info("Lockless commit start, basing commit on '$tmpdir', index file is '$file_index'");
$ENV{GIT_DIR} = $state->{CVSROOT} . "/";
$ENV{GIT_INDEX_FILE} = $file_index;
+ # Remember where the head was at the beginning.
+ my $parenthash = `git show-ref -s refs/heads/$state->{module}`;
+ chomp $parenthash;
+ if ($parenthash !~ /^[0-9a-f]{40}$/) {
+ print "error 1 pserver cannot find the current HEAD of module";
+ exit;
+ }
+
chdir $tmpdir;
# populate the temporary index based
- system("git-read-tree", $state->{module});
+ system("git-read-tree", $parenthash);
unless ($? == 0)
{
die "Error running git-read-tree $state->{module} $file_index $!";
}
$log->info("Created index '$file_index' with for head $state->{module} - exit status $?");
-
my @committedfiles = ();
# foreach file specified on the command line ...
@@ -1095,8 +1094,6 @@ sub req_ci
{
# fail everything if an up to date check fails
print "error 1 Up to date check failed for $filename\n";
- close LOCKFILE;
- unlink($lockfile);
chdir "/";
exit;
}
@@ -1139,16 +1136,12 @@ sub req_ci
{
print "E No files to commit\n";
print "ok\n";
- close LOCKFILE;
- unlink($lockfile);
chdir "/";
return;
}
my $treehash = `git-write-tree`;
- my $parenthash = `cat $ENV{GIT_DIR}refs/heads/$state->{module}`;
chomp $treehash;
- chomp $parenthash;
$log->debug("Treehash : $treehash, Parenthash : $parenthash");
@@ -1165,8 +1158,6 @@ sub req_ci
{
$log->warn("Commit failed (Invalid commit hash)");
print "error 1 Commit failed (unknown reason)\n";
- close LOCKFILE;
- unlink($lockfile);
chdir "/";
exit;
}
@@ -1179,14 +1170,17 @@ sub req_ci
{
$log->warn("Commit failed (update hook declined to update ref)");
print "error 1 Commit failed (update hook declined)\n";
- close LOCKFILE;
- unlink($lockfile);
chdir "/";
exit;
}
}
- print LOCKFILE $commithash;
+ if (system(qw(git update-ref -m), "cvsserver ci",
+ "refs/heads/$state->{module}", $commithash, $parenthash)) {
+ $log->warn("update-ref for $state->{module} failed.");
+ print "error 1 Cannot commit -- update first\n";
+ exit;
+ }
$updater->update();
@@ -1215,12 +1209,7 @@ sub req_ci
}
}
- close LOCKFILE;
- my $reffile = "$ENV{GIT_DIR}refs/heads/$state->{module}";
- unlink($reffile);
- rename($lockfile, $reffile);
chdir "/";
-
print "ok\n";
}