Add delete_device support

lib/MogileFS/Store.pm

@@ -1227,16 +1227,27 @@ sub update_device_usage {
 }
 
 # This is unimplemented at the moment as we must verify:
-# - no file_on rows exist
-# - nothing in file_to_queue is going to attempt to use it
-# - nothing in file_to_replicate is going to attempt to use it
-# - it's already been marked dead
-# - that all trackers are likely to know this :/
-# - ensure the devid can't be reused
+# - no file_on rows exist                                      (DONE)(file_on_device = 0)
+# - nothing in file_to_queue is going to attempt to use it     (DONE)(file_to_device = 0)
+# - nothing in file_to_replicate is going to attempt to use it (SKIP)(no file on it means no file will be replicated from. "dead" means no file can go there)
+# - it's already been marked dead                              (DONE)($dev->status eq "dead")
+# - that all trackers are likely to know this :/               (SKIP)(all trackers should point to the same database to share this info)
+# - ensure the devid can't be reused                           (DONE)(keep PRI devid, set hostid = 0)
 # IE; the user can't mark it dead then remove it all at once and cause their
 # cluster to implode.
 sub delete_device {
-    die "Unimplemented; needs further testing";
+    my ($self, $devid, $hostid) = @_;
+    return $self->dbh->do("UPDATE device SET hostid = 0 where devid = ?", undef, $devid);
+}
+
+sub file_on_device {
+    my ($self, $devid) = @_;
+    return $self->dbh->selectrow_array('SELECT COUNT(*) FROM file_on WHERE devid = ?', undef, $devid);
+}
+
+sub file_to_device {
+    my ($self, $devid) = @_;
+    return $self->dbh->selectrow_array('SELECT COUNT(*) FROM file_to_queue WHERE arg like ?', undef, "%$devid%");
 }
 
 sub mark_fidid_unreachable {
@@ -1439,7 +1450,7 @@ sub get_all_hosts {
 sub get_all_devices {
     my ($self) = @_;
     my $sth = $self->dbh->prepare("SELECT /*!40000 SQL_CACHE */ devid, hostid, mb_total, " .
-                                  "mb_used, mb_asof, status, weight FROM device");
+                                  "mb_used, mb_asof, status, weight FROM device where hostid > 0");
     $self->condthrow;
     $sth->execute;
     my @return;

lib/MogileFS/Worker/Query.pm

@@ -850,6 +850,35 @@ sub cmd_create_device {
     die $@;  # rethrow;
 }
 
+sub cmd_delete_device {
+    my MogileFS::Worker::Query $self = shift;
+    my $args = shift;
+    my $devid = $args->{devid};
+    my $hostname = $args->{host};
+
+    my $dev = Mgd::device_factory()->get_by_id($devid);
+    my $sto = Mgd::get_store();
+
+    # ensure device exists
+    return $self->err_line('no_device') unless $dev;
+
+    # ensure device matches its host
+    return $self->err_line('host_mismatch') unless $dev->host->hostname eq $hostname;
+
+    # ensure no files on device
+    return $self->err_line('device_has_files') if $sto->file_on_device($devid);
+
+    # ensure no files is going to device
+    return $self->err_line('device_in_queue') if $sto->file_to_device($devid);
+
+    # ensure device is marked as dead
+    return $self->err_line('device_not_dead') unless $dev->status eq "dead";
+
+    $sto->delete_device($devid, $dev->host->id);
+
+    return $self->cmd_clear_cache;
+}
+
 sub cmd_create_domain {
     my MogileFS::Worker::Query $self = shift;
     my $args = shift;
@@ -1778,6 +1807,9 @@ sub err_line {
         'class_has_files' => "Class still has files, unable to delete",
         'class_not_found' => "Class not found",
         'db' => "Database error",
+        'device_has_files' => "Device still has files, unable to delete",
+        'device_not_dead' => "Device isn't marked as dead, unable to delete",
+        'device_in_queue' => "Device is in queue to receive files",
         'domain_has_files' => "Domain still has files, unable to delete",
         'domain_exists' => "That domain already exists",
         'domain_not_empty' => "Domain still has classes, unable to delete",