From 5d8a5636485786c02797b63690acb4867b972eaf Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Mon, 21 Oct 2013 18:36:01 +0000
Subject: [PATCH] scstadmin: Reduce the time needed to save or restore a
 configuration

git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@5075 d57e44dd-8a1f-0410-8b47-8ef2f437770f
---
 .../scst-0.9.10/lib/SCST/SCST.pm              | 2499 ++++++++---------
 1 file changed, 1149 insertions(+), 1350 deletions(-)

diff --git a/scstadmin/scstadmin.sysfs/scst-0.9.10/lib/SCST/SCST.pm b/scstadmin/scstadmin.sysfs/scst-0.9.10/lib/SCST/SCST.pm
index 613fc8f4a..d9de2362d 100644
--- a/scstadmin/scstadmin.sysfs/scst-0.9.10/lib/SCST/SCST.pm
+++ b/scstadmin/scstadmin.sysfs/scst-0.9.10/lib/SCST/SCST.pm
@@ -501,15 +501,26 @@ sub scstAttributes {
 						$attributes{$attribute}->{'value'} = $value;
 					}
 				}
+				close $io;
 
 				$attributes{$attribute}->{'static'} = $is_static;
 			}
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
+sub setAttrFailed {
+	my $path = shift;
+	my $no_such_attr = shift;
+	my $is_static = shift;
+
+	return (-f $path) && (-r $path) ? $is_static : $no_such_attr;
+}
+
 sub setScstAttribute {
 	my $self = shift;
 	my $attribute = shift;
@@ -517,29 +528,20 @@ sub setScstAttribute {
 
 	return TRUE if (!defined($attribute) || !defined($value));
 
-	my $attributes = $self->scstAttributes();
-
-	return SCST_C_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
-	return SCST_C_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
-
 	my $path = make_path(SCST_ROOT_DIR(), $attribute);
-
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $attribute = $value\n";
-	} else {
-		$bytes = _syswrite($io, $value, length($value));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $attribute = $value\n";
+		} else {
+			$bytes = _syswrite($io, $value, length($value));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_SETATTR_FAIL;
+	return setAttrFailed($path, SCST_C_BAD_ATTRIBUTES,
+			     SCST_C_ATTRIBUTE_STATIC);
 }
 
 my @_drivers;
@@ -570,76 +572,70 @@ sub drivers {
 sub targets {
 	my $self = shift;
 	my $driver = shift;
-	my @targets;
 
 	return undef if (!defined($driver));
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "targets(): Driver '$driver' is not available";
-		return undef;
-	}
-
 	my $tHandle = new IO::Handle;
 	my $_path = make_path(SCST_TARGETS_DIR(), $driver);
-	if (!(opendir $tHandle, $_path)) {
-		$self->{'err_string'} = "targets(): Unable to read directory '$_path': $!";
-		return undef;
-	}
+	if (opendir $tHandle, $_path) {
+		my @targets;
 
-	foreach my $target (readdir($tHandle)) {
-		next if ($target eq '.' || $target eq '..' ||
-			 $target eq 'module');
+		foreach my $target (readdir($tHandle)) {
+			next if ($target eq '.' || $target eq '..' ||
+				 $target eq 'module');
 
-		if (-d make_path(SCST_TARGETS_DIR(), $driver, $target)) {
-			push @targets, $target;
+			if (-d make_path(SCST_TARGETS_DIR(), $driver,
+					 $target)) {
+				push @targets, $target;
+			}
 		}
+		close $tHandle;
+		@targets = sort(@targets);
+		return \@targets;
+	}
+	if ($self->driverExists($driver) != TRUE) {
+		$self->{'err_string'} = "targets(): Driver '$driver' is not available";
+	} else {
+		$self->{'err_string'} = "targets(): Unable to read directory '$_path': $!";
 	}
 
-	close $tHandle;
-
-	@targets = sort(@targets);
-
-	return \@targets;
+	return undef;
 }
 
 sub groups {
 	my $self = shift;
 	my $driver = shift;
 	my $target = shift;
-	my @groups;
 
 	return undef if (!defined($driver) || !defined($target));
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "groups(): Driver '$driver' is not available";
-		return undef;
-	}
-
-	if ($self->targetExists($driver, $target) != TRUE) {
-		$self->{'err_string'} = "groups(): Target '$target' is not available";
-		return undef;
-	}
-
 	my $gHandle = new IO::Handle;
 	my $_path = make_path(SCST_TARGETS_DIR(), $driver, $target,
 			      SCST_GROUPS);
-	if (!(opendir $gHandle, $_path)) {
-		$self->{'err_string'} = "groups(): Unable to read directory '$_path': $!";
-		return undef;
-	}
 
-	foreach my $group (readdir($gHandle)) {
-		next if (($group eq '.') || ($group eq '..'));
+	if (opendir $gHandle, $_path) {
+		my @groups;
 
-		if (-d make_path(SCST_TARGETS_DIR(), $driver,
-				 $target, SCST_GROUPS, $group)) {
-			push @groups, $group;
+		foreach my $group (readdir($gHandle)) {
+			next if ($group eq '.' || $group eq '..');
+
+			if (-d make_path(SCST_TARGETS_DIR(), $driver,
+					 $target, SCST_GROUPS, $group)) {
+				push @groups, $group;
+			}
 		}
+		close $gHandle;
+		return \@groups;
 	}
 
-	close $gHandle;
-
-	return \@groups;
+	if ($self->driverExists($driver) != TRUE) {
+		$self->{'err_string'} = "groups(): Driver '$driver' is not available";
+	} elsif ($self->targetExists($driver, $target) != TRUE) {
+		$self->{'err_string'} = "groups(): Target '$target' is not available";
+	} else {
+		$self->{'err_string'} = "groups(): Unable to read directory '$_path': $!";
+	}
+	return undef;
 }
 
 sub initiators {
@@ -652,26 +648,19 @@ sub initiators {
 	return undef if (!defined($driver) || !defined($target) ||
 			 !defined($group));
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "initiators(): Driver '$driver' is not available";
-		return undef;
-	}
-
-	if ($self->targetExists($driver, $target) != TRUE) {
-		$self->{'err_string'} = "initiators(): Target '$target' is not available";
-		return undef;
-	}
-
-	if ($self->groupExists($driver, $target, $group) != TRUE) {
-		$self->{'err_string'} = "initiators(): Group '$group' does not exist";
-		return undef;
-	}
-
 	my $iHandle = new IO::Handle;
 	my $_path = make_path(SCST_TARGETS_DIR(), $driver, $target, SCST_GROUPS,
 			      $group, SCST_INITIATORS);
 	if (!(opendir $iHandle, $_path)) {
-		$self->{'err_string'} = "initiators(): Unable to read directory '$_path': $!";
+		if ($self->driverExists($driver) != TRUE) {
+			$self->{'err_string'} = "initiators(): Driver '$driver' is not available";
+		} elsif ($self->targetExists($driver, $target) != TRUE) {
+			$self->{'err_string'} = "initiators(): Target '$target' is not available";
+		} elsif ($self->groupExists($driver, $target, $group) != TRUE) {
+			$self->{'err_string'} = "initiators(): Group '$group' does not exist";
+		} else {
+			$self->{'err_string'} = "initiators(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -692,28 +681,12 @@ sub luns {
 	my $driver = shift;
 	my $target = shift;
 	my $group = shift;
-	my %luns;
 
 	return undef if (!defined($driver) || !defined($target));
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "luns(): Driver '$driver' is not available";
-		return undef;
-	}
-
-	if ($self->targetExists($driver, $target) != TRUE) {
-		$self->{'err_string'} = "luns(): Target '$target' is not available";
-		return undef;
-	}
-
 	my $_path;
 
 	if (defined($group)) {
-		if ($self->groupExists($driver, $target, $group) != TRUE) {
-			$self->{'err_string'} = "initiators(): Group '$group' does not exist";
-			return undef;
-		}
-
 		$_path = make_path(SCST_TARGETS_DIR(), $driver, $target,
 				   SCST_GROUPS, $group, SCST_LUNS);
 	} else {
@@ -724,10 +697,20 @@ sub luns {
 	my $lHandle = new IO::Handle;
 
 	if (!(opendir $lHandle, $_path)) {
-		$self->{'err_string'} = "luns(): Unable to read directory '$_path': $!";
+		if (defined($group) && $self->groupExists($driver, $target, $group) != TRUE) {
+			$self->{'err_string'} = "initiators(): Group '$group' does not exist";
+		} elsif ($self->driverExists($driver) != TRUE) {
+			$self->{'err_string'} = "luns(): Driver '$driver' is not available";
+		} elsif ($self->targetExists($driver, $target) != TRUE) {
+			$self->{'err_string'} = "luns(): Target '$target' is not available";
+		} else {
+			$self->{'err_string'} = "luns(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
+	my %luns;
+
 	foreach my $lun (readdir($lHandle)) {
 		next if (($lun eq '.') || ($lun eq '..'));
 
@@ -750,6 +733,8 @@ sub luns {
 					$luns{$lun} = $linked;
 				}
 			}
+
+			close $_lHandle;
 		}
 	}
 
@@ -802,10 +787,14 @@ sub aluaAttributes {
 			} else {
 				$attributes{$attribute}->{'value'} = $value;
 			}
+			close $io;
+
 			$attributes{$attribute}->{'static'} = $is_static;
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
@@ -840,15 +829,14 @@ sub deviceGroupDevices {
 
 	return undef if (!defined($group));
 
-	if ($self->deviceGroupExists($group) != TRUE) {
-		$self->{'err_string'} = "deviceGroupDevices(): Device group '$group' does not exist";
-		return undef;
-	}
-
 	my $dHandle = new IO::Handle;
 	my $_path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_DEVICES);
 	if (!(opendir $dHandle, $_path)) {
-		$self->{'err_string'} = "deviceGroupDevices(): Unable to read directory '$_path': $!";
+		if ($self->deviceGroupExists($group) != TRUE) {
+			$self->{'err_string'} = "deviceGroupDevices(): Device group '$group' does not exist";
+		} else {
+			$self->{'err_string'} = "deviceGroupDevices(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -872,15 +860,14 @@ sub targetGroups {
 
 	return undef if (!defined($group));
 
-	if ($self->deviceGroupExists($group) != TRUE) {
-		$self->{'err_string'} = "targetGroups(): Device group '$group' does not exist";
-		return undef;
-	}
-
 	my $dHandle = new IO::Handle;
 	my $_path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_TGROUPS);
 	if (!(opendir $dHandle, $_path)) {
-		$self->{'err_string'} = "targetGroups(): Unable to read directory '$_path': $!";
+		if ($self->deviceGroupExists($group) != TRUE) {
+			$self->{'err_string'} = "targetGroups(): Device group '$group' does not exist";
+		} else {
+			$self->{'err_string'} = "targetGroups(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -905,20 +892,16 @@ sub targetGroupTargets {
 
 	return undef if (!defined($group) || !defined($tgroup));
 
-	if ($self->deviceGroupExists($group) != TRUE) {
-		$self->{'err_string'} = "targetGroupTargets(): Device group '$group' does not exist";
-		return undef;
-	}
-
-	if ($self->targetGroupExists($group, $tgroup) != TRUE) {
-		$self->{'err_string'} = "targetGroupTargets(): Target group '$tgroup' does not exist";
-		return undef;
-	}
-
 	my $dHandle = new IO::Handle;
 	my $_path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_TGROUPS, $tgroup);
 	if (!(opendir $dHandle, $_path)) {
-		$self->{'err_string'} = "targetGroupTargets(): Unable to read directory '$_path': $!";
+		if ($self->deviceGroupExists($group) != TRUE) {
+			$self->{'err_string'} = "targetGroupTargets(): Device group '$group' does not exist";
+		} elsif ($self->targetGroupExists($group, $tgroup) != TRUE) {
+			$self->{'err_string'} = "targetGroupTargets(): Target group '$tgroup' does not exist";
+		} else {
+			$self->{'err_string'} = "targetGroupTargets(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -960,12 +943,6 @@ sub driverDynamicAttributes {
 
 	return undef if (!defined($driver));
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "driverDynamicAttributes(): Driver '$driver' ".
-		  "is not available";
-		return undef;
-	}
-
 	if (new_sysfs_interface()) {
 		my $io = new IO::File make_path(SCST_TARGETS_DIR(), $driver,
 						SCST_TGTT_ATTR), O_RDONLY;
@@ -974,14 +951,20 @@ sub driverDynamicAttributes {
 				chomp($attribute);
 				$attributes{$attribute} = '';
 			}
+			close $io;
 		}
 	} else {
 		my $io = new IO::File make_path(SCST_TARGETS_DIR(), $driver,
 						SCST_MGMT_IO), O_RDONLY;
 
 		if (!$io) {
-			$self->{'err_string'} = "driverDynamicAttributes(): Unable to open mgmt ".
-			    "interface for driver '$driver': $!";
+			if ($self->driverExists($driver) != TRUE) {
+				$self->{'err_string'} = "driverDynamicAttributes(): Driver '$driver' ".
+				    "is not available";
+			} else {
+				$self->{'err_string'} = "driverDynamicAttributes(): Unable to open mgmt ".
+				    "interface for driver '$driver': $!";
+			}
 			return undef;
 		}
 
@@ -991,6 +974,7 @@ sub driverDynamicAttributes {
 				$available =~ s/\.$//;
 			}
 		}
+		close $io;
 
 		if ($available) {
 			foreach my $attribute (split(/\,/, $available)) {
@@ -1009,13 +993,15 @@ sub checkDriverDynamicAttributes {
 	my $driver = shift;
 	my $check = shift;
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if (!$rc > 1);
-
 	my $available = $self->driverDynamicAttributes($driver);
 
-	return SCST_C_FATAL_ERROR if (!defined($available));
+	if (!defined($available)) {
+		my $rc = $self->driverExists($driver);
+		return SCST_C_DRV_NO_DRIVER if (!$rc);
+		return $rc if (!$rc > 1);
+
+		return SCST_C_FATAL_ERROR;
+	}
 
 	return FALSE if (!defined($check));
 
@@ -1043,16 +1029,6 @@ sub addDriverDynamicAttribute {
 	return SCST_C_DRV_ADDATTR_FAIL
 	    if (!defined($driver) || !defined($attribute) || !defined($value));
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	return SCST_C_DRV_NOTVIRT if (!$self->driverIsVirtualCapable($driver));
-
-	$rc = $self->checkDriverDynamicAttributes($driver, $attribute);
-	return SCST_C_DRV_BAD_ATTRIBUTES if ($rc == 1);
-	return $rc if ($rc > 1);
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -1063,22 +1039,28 @@ sub addDriverDynamicAttribute {
 	$cmd .= "add_attribute $attribute $value";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DRV_ADDATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
+
+	return SCST_C_DRV_NOTVIRT if (!$self->driverIsVirtualCapable($driver));
+
+	$rc = $self->checkDriverDynamicAttributes($driver, $attribute);
+	return SCST_C_DRV_BAD_ATTRIBUTES if ($rc == 1);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_DRV_ADDATTR_FAIL;
-
 }
 
 sub removeDriverDynamicAttribute {
@@ -1090,16 +1072,6 @@ sub removeDriverDynamicAttribute {
 	return SCST_C_DRV_REMATTR_FAIL
 	    if (!defined($driver) || !defined($attribute) || !defined($value));
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	return SCST_C_DRV_NOTVIRT if (!$self->driverIsVirtualCapable($driver));
-
-	$rc = $self->checkDriverDynamicAttributes($driver, $attribute);
-	return SCST_C_DRV_BAD_ATTRIBUTES if ($rc == 1);
-	return $rc if ($rc > 1);
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -1110,20 +1082,27 @@ sub removeDriverDynamicAttribute {
 	$cmd .= "del_attribute $attribute $value";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DRV_REMATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
+
+	return SCST_C_DRV_NOTVIRT if (!$self->driverIsVirtualCapable($driver));
+
+	$rc = $self->checkDriverDynamicAttributes($driver, $attribute);
+	return SCST_C_DRV_BAD_ATTRIBUTES if ($rc == 1);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_DRV_REMATTR_FAIL;
 }
 
@@ -1132,37 +1111,21 @@ sub targetExists {
 	my $driver = shift;
 	my $target = shift;
 
-	return FALSE if (!defined($target));
-
-	my $rc = $self->driverExists($driver);
-
-	return FALSE if (!$rc);
-	return $rc if ($rc > 1);
-
-	my $targets = $self->targets($driver);
-
-	return SCST_C_FATAL_ERROR if (!defined($targets));
-
-	foreach my $_target (@{$targets}) {
-		return TRUE if ($target eq $_target);
-	}
-
-	return FALSE;
+	return defined($driver) && defined($target) &&
+	    $target ne '.' && $target ne '..' && $target ne 'module' &&
+	    (-d make_path(SCST_TARGETS_DIR(), $driver, $target)) ? TRUE : FALSE;
 }
 
 sub driverIsVirtualCapable {
 	my $self = shift;
 	my $driver = shift;
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
 	if (new_sysfs_interface()) {
 		my $path = make_path(SCST_TARGETS_DIR(), $driver, SCST_ADD_TGT);
 		my $io = new IO::File $path, O_RDONLY;
 		if ($io) {
 			my $line = <$io>;
+			close $io;
 			chomp($line);
 			return $line eq '1';
 		}
@@ -1200,20 +1163,6 @@ sub addVirtualTarget {
 	my $target = shift;
 	my $attributes = shift;
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_EXISTS if ($rc);
-	return $rc if ($rc > 1);
-
-	return SCST_C_DRV_NOTVIRT if (!$self->driverIsVirtualCapable($driver));
-
-	$rc = $self->checkTargetCreateAttributes($driver, $attributes);
-	return SCST_C_TGT_BAD_ATTRIBUTES if ($rc == TRUE);
-	return $rc if ($rc > 1);
-
 	my $o_string = "";
 	foreach my $attribute (keys %{$attributes}) {
 		if (ref($$attributes{$attribute}) eq 'ARRAY') {
@@ -1238,20 +1187,31 @@ sub addVirtualTarget {
 	$cmd .= "add_target $target $o_string";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_TGT_ADD_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetExists($driver, $target);
+	return SCST_C_TGT_EXISTS if ($rc);
+	return $rc if ($rc > 1);
+
+	return SCST_C_DRV_NOTVIRT if (!$self->driverIsVirtualCapable($driver));
+
+	$rc = $self->checkTargetCreateAttributes($driver, $attributes);
+	return SCST_C_TGT_BAD_ATTRIBUTES if ($rc == TRUE);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_TGT_ADD_FAIL;
 }
 
@@ -1263,12 +1223,6 @@ sub targetDynamicAttributes {
 
 	return undef if (!defined($driver));
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "targetDynamicAttributes(): Driver '$driver' ".
-		  "is not available";
-		return undef;
-	}
-
 	if (new_sysfs_interface()) {
 		my $io = new IO::File make_path(SCST_TARGETS_DIR(), $driver,
 						SCST_TGT_ATTR), O_RDONLY;
@@ -1277,14 +1231,20 @@ sub targetDynamicAttributes {
 				chomp($attribute);
 				$attributes{$attribute} = '';
 			}
+			close $io;
 		}
 	} else {
 		my $io = new IO::File make_path(SCST_TARGETS_DIR(), $driver,
 						SCST_MGMT_IO), O_RDONLY;
 
 		if (!$io) {
-			$self->{'err_string'} = "targetDynamicAttributes(): Unable to open mgmt ".
-			    "interface for driver '$driver': $!";
+			if ($self->driverExists($driver) != TRUE) {
+				$self->{'err_string'} = "targetDynamicAttributes(): Driver '$driver' ".
+				    "is not available";
+			} else {
+				$self->{'err_string'} = "targetDynamicAttributes(): Unable to open mgmt ".
+				    "interface for driver '$driver': $!";
+			}
 			return undef;
 		}
 
@@ -1294,6 +1254,7 @@ sub targetDynamicAttributes {
 				$available =~ s/\.$//;
 			}
 		}
+		close $io;
 
 		if ($available) {
 			foreach my $attribute (split(/\,/, $available)) {
@@ -1312,13 +1273,15 @@ sub checkTargetDynamicAttributes {
 	my $driver = shift;
 	my $check = shift;
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if (!$rc > 1);
-
 	my $available = $self->targetDynamicAttributes($driver);
 
-	return SCST_C_FATAL_ERROR if (!defined($available));
+	if (!defined($available)) {
+		my $rc = $self->driverExists($driver);
+		return SCST_C_DRV_NO_DRIVER if (!$rc);
+		return $rc if (!$rc > 1);
+
+		return SCST_C_FATAL_ERROR;
+	}
 
 	return FALSE if (!defined($check));
 
@@ -1348,6 +1311,27 @@ sub addTargetDynamicAttribute {
 	    if (!defined($driver) || !defined($target) ||
 		!defined($attribute) || !defined($value));
 
+	my ($path, $cmd);
+	if (new_sysfs_interface()) {
+		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
+		$cmd = "in " . make_path(IN_SCST_TARGETS, $driver) . " ";
+	} else {
+		$path = make_path(SCST_TARGETS_DIR(), $driver, SCST_MGMT_IO);
+	}
+	$cmd .= "add_target_attribute $target $attribute $value";
+
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->driverExists($driver);
 	return SCST_C_DRV_NO_DRIVER if (!$rc);
 	return $rc if ($rc > 1);
@@ -1362,30 +1346,6 @@ sub addTargetDynamicAttribute {
 	return SCST_C_TGT_BAD_ATTRIBUTES if ($rc == 1);
 	return $rc if ($rc > 1);
 
-	my ($path, $cmd);
-	if (new_sysfs_interface()) {
-		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
-		$cmd = "in " . make_path(IN_SCST_TARGETS, $driver) . " ";
-	} else {
-		$path = make_path(SCST_TARGETS_DIR(), $driver, SCST_MGMT_IO);
-	}
-	$cmd .= "add_target_attribute $target $attribute $value";
-
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_TGT_ADDATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_TGT_ADDATTR_FAIL;
 }
 
@@ -1400,6 +1360,27 @@ sub removeTargetDynamicAttribute {
 	    if (!defined($driver) || !defined($target) ||
 		!defined($attribute) || !defined($value));
 
+	my ($path, $cmd);
+	if (new_sysfs_interface()) {
+		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
+		$cmd = "in " . make_path(IN_SCST_TARGETS, $driver) . " ";
+	} else {
+		$path = make_path(SCST_TARGETS_DIR(), $driver, SCST_MGMT_IO);
+	}
+	$cmd .= "del_target_attribute $target $attribute $value";
+
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->driverExists($driver);
 	return SCST_C_DRV_NO_DRIVER if (!$rc);
 	return $rc if ($rc > 1);
@@ -1414,30 +1395,6 @@ sub removeTargetDynamicAttribute {
 	return SCST_C_TGT_BAD_ATTRIBUTES if ($rc == 1);
 	return $rc if ($rc > 1);
 
-	my ($path, $cmd);
-	if (new_sysfs_interface()) {
-		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
-		$cmd = "in " . make_path(IN_SCST_TARGETS, $driver) . " ";
-	} else {
-		$path = make_path(SCST_TARGETS_DIR(), $driver, SCST_MGMT_IO);
-	}
-	$cmd .= "del_target_attribute $target $attribute $value";
-
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_TGT_REMATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_TGT_REMATTR_FAIL;
 }
 
@@ -1446,16 +1403,8 @@ sub removeVirtualTarget {
 	my $driver = shift;
 	my $target = shift;
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	return SCST_C_DRV_NOTVIRT if (!$self->driverIsVirtualCapable($driver));
-
+	# May fail if the target does not have an 'enabled' attribute as is the
+	# case for e.g. the 'scst_local' driver.
 	$self->enableTarget($driver, $target, FALSE);
 
 	my $sessions = $self->sessions($driver, $target);
@@ -1498,20 +1447,27 @@ sub removeVirtualTarget {
 	$cmd .= "del_target $target";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_TGT_REM_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetExists($driver, $target);
+	return SCST_C_TGT_NO_TARGET if (!$rc);
+	return $rc if ($rc > 1);
+
+	return SCST_C_DRV_NOTVIRT if (!$self->driverIsVirtualCapable($driver));
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_TGT_REM_FAIL;
 }
 
@@ -1523,14 +1479,15 @@ sub groupExists {
 
 	return FALSE if (!defined($driver) || !defined($target) || !defined($group));
 
-	my $rc = $self->targetExists($driver, $target);
-
-	return FALSE if (!$rc);
-	return $rc if ($rc > 1);
-
 	my $groups = $self->groups($driver, $target);
 
-	return SCST_C_FATAL_ERROR if (!defined($groups));
+	if (!defined($groups)) {
+		my $rc = $self->targetExists($driver, $target);
+		return FALSE if (!$rc);
+		return $rc if ($rc > 1);
+
+		return SCST_C_FATAL_ERROR;
+	}
 
 	foreach my $_group (@{$groups}) {
 		return TRUE if ($group eq $_group);
@@ -1549,14 +1506,15 @@ sub initiatorExists {
 	return FALSE if (!defined($driver) || !defined($target) ||
 			 !defined($group) || !defined($initiator));
 
-	my $rc = $self->groupExists($driver, $target, $group);
-
-	return FALSE if (!$rc);
-	return $rc if ($rc > 1);
-
 	my $initiators = $self->initiators($driver, $target, $group);
 
-	return SCST_C_FATAL_ERROR if (!defined($initiators));
+	if (!defined($initiators)) {
+		my $rc = $self->groupExists($driver, $target, $group);
+		return FALSE if (!$rc);
+		return $rc if ($rc > 1);
+
+		return SCST_C_FATAL_ERROR;
+	}
 
 	foreach my $_initiator (@{$initiators}) {
 		return TRUE if ($initiator eq $_initiator);
@@ -1575,24 +1533,24 @@ sub lunExists {
 	return FALSE if (!defined($driver) || !defined($target) ||
 			 !defined($lun));
 
-
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	if (defined($group)) {
-		my $rc = $self->groupExists($driver, $target, $group);
-		return SCST_C_GRP_NO_GROUP if (!$rc);
-		return $rc if ($rc > 1);
-	}
-
 	my $luns = $self->luns($driver, $target, $group);
 
-	return SCST_C_FATAL_ERROR if (!defined($luns));
+	if (!defined($luns)) {
+		my $rc = $self->driverExists($driver);
+		return SCST_C_DRV_NO_DRIVER if (!$rc);
+		return $rc if ($rc > 1);
+
+		$rc = $self->targetExists($driver, $target);
+		return SCST_C_TGT_NO_TARGET if (!$rc);
+		return $rc if ($rc > 1);
+
+		if (defined($group)) {
+			my $rc = $self->groupExists($driver, $target, $group);
+			return SCST_C_GRP_NO_GROUP if (!$rc);
+			return $rc if ($rc > 1);
+		}
+		return SCST_C_FATAL_ERROR;
+	}
 
 	foreach my $_lun (keys %{$luns}) {
 		return TRUE if ($lun == $_lun);
@@ -1610,18 +1568,6 @@ sub addGroup {
 	return SCST_C_GRP_ADD_FAIL if (!defined($driver) || !defined($target) ||
 				       !defined($group));
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->groupExists($driver, $target, $group);
-	return SCST_C_GRP_EXISTS if ($rc == TRUE);
-	return $rc if ($rc > 1);
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -1634,20 +1580,29 @@ sub addGroup {
 	$cmd .= "create $group";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_GRP_ADD_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetExists($driver, $target);
+	return SCST_C_TGT_NO_TARGET if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->groupExists($driver, $target, $group);
+	return SCST_C_GRP_EXISTS if ($rc == TRUE);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_GRP_ADD_FAIL;
 }
 
@@ -1660,6 +1615,29 @@ sub removeGroup {
 	return SCST_C_GRP_REM_FAIL if (!defined($driver) || !defined($target) ||
 				       !defined($group));
 
+	my ($path, $cmd);
+	if (new_sysfs_interface()) {
+		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
+		$cmd = "in " . make_path(IN_SCST_TARGETS, $driver, $target,
+					 SCST_GROUPS) . " ";
+	} else {
+		$path = make_path(SCST_TARGETS_DIR(), $driver, $target,
+				  SCST_GROUPS, SCST_MGMT_IO);
+	}
+	$cmd .= "del $group";
+
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->driverExists($driver);
 	return SCST_C_DRV_NO_DRIVER if (!$rc);
 	return $rc if ($rc > 1);
@@ -1672,32 +1650,6 @@ sub removeGroup {
 	return SCST_C_GRP_NO_GROUP if (!$rc);
 	return $rc if ($rc > 1);
 
-	my ($path, $cmd);
-	if (new_sysfs_interface()) {
-		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
-		$cmd = "in " . make_path(IN_SCST_TARGETS, $driver, $target,
-					 SCST_GROUPS) . " ";
-	} else {
-		$path = make_path(SCST_TARGETS_DIR(), $driver, $target,
-				  SCST_GROUPS, SCST_MGMT_IO);
-	}
-	$cmd .= "del $group";
-
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_GRP_REM_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_GRP_REM_FAIL;
 }
 
@@ -1707,10 +1659,6 @@ sub addDeviceGroup {
 
 	return SCST_C_DEV_GRP_ADD_FAIL if (!defined($group));
 
-	my $rc = $self->deviceGroupExists($group);
-	return SCST_C_DEV_GRP_EXISTS if ($rc == TRUE);
-	return $rc if ($rc > 1);
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -1721,21 +1669,20 @@ sub addDeviceGroup {
 	$cmd .= "create $group";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DEV_GRP_ADD_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_DEV_GRP_ADD_FAIL;
+	my $rc = $self->deviceGroupExists($group);
+	return $rc == TRUE ? SCST_C_DEV_GRP_EXISTS : $rc > 1 ? $rc :
+	    SCST_C_DEV_GRP_ADD_FAIL;
 }
 
 sub removeDeviceGroup {
@@ -1744,10 +1691,6 @@ sub removeDeviceGroup {
 
 	return SCST_C_DEV_GRP_REM_FAIL if (!defined($group));
 
-	my $rc = $self->deviceGroupExists($group);
-	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -1758,20 +1701,21 @@ sub removeDeviceGroup {
 	$cmd .= "del $group";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DEV_GRP_REM_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->deviceGroupExists($group);
+	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_DEV_GRP_REM_FAIL;
 }
 
@@ -1782,6 +1726,28 @@ sub addDeviceGroupDevice {
 
 	return SCST_C_DGRP_ADD_DEV_FAIL if (!defined($group) || !defined($device));
 
+	my ($path, $cmd);
+	if (new_sysfs_interface()) {
+		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
+		$cmd = "in " . make_path(IN_SCST_DEV_GROUPS, $group,
+					 SCST_DG_DEVICES) . " ";
+	} else {
+		$path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_DEVICES, SCST_MGMT_IO);
+	}
+	$cmd .= "add $device";
+
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->deviceGroupExists($group);
 	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
 	return $rc if ($rc > 1);
@@ -1805,31 +1771,6 @@ sub addDeviceGroupDevice {
 		}
 	}
 
-	my ($path, $cmd);
-	if (new_sysfs_interface()) {
-		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
-		$cmd = "in " . make_path(IN_SCST_DEV_GROUPS, $group,
-					 SCST_DG_DEVICES) . " ";
-	} else {
-		$path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_DEVICES, SCST_MGMT_IO);
-	}
-	$cmd .= "add $device";
-
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DGRP_ADD_DEV_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_DGRP_ADD_DEV_FAIL;
 }
 
@@ -1838,15 +1779,8 @@ sub addTargetGroup {
 	my $group = shift;
 	my $tgroup = shift;
 
-	return SCST_C_DGRP_ADD_GRP_FAIL if (!defined($group) || !defined($tgroup));
-
-	my $rc = $self->deviceGroupExists($group);
-	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetGroupExists($group, $tgroup);
-	return SCST_C_DGRP_GROUP_EXISTS if ($rc == TRUE);
-	return $rc if ($rc > 1);
+	return SCST_C_DGRP_ADD_GRP_FAIL if (!defined($group) ||
+					    !defined($tgroup));
 
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
@@ -1859,21 +1793,24 @@ sub addTargetGroup {
 	$cmd .= "add $tgroup";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DGRP_ADD_GRP_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->deviceGroupExists($group);
+	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_DGRP_ADD_GRP_FAIL;
+	$rc = $self->targetGroupExists($group, $tgroup);
+	return SCST_C_DGRP_GROUP_EXISTS if ($rc == TRUE);
+	return $rc > 1 ? $rc : SCST_C_DGRP_ADD_GRP_FAIL;
 }
 
 sub addTargetGroupTarget {
@@ -1882,19 +1819,9 @@ sub addTargetGroupTarget {
 	my $tgroup = shift;
 	my $tgt = shift;
 
-	return SCST_C_TGRP_ADD_TGT_FAIL if (!defined($group) || !defined($tgroup) || !defined($tgt));
-
-	my $rc = $self->deviceGroupExists($group);
-	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetGroupExists($group, $tgroup);
-	return SCST_C_DGRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetGroupTargetExists($group, $tgroup, $tgt);
-	return SCST_C_TGRP_TGT_EXISTS if ($rc == TRUE);
-	return $rc if ($rc > 1);
+	return SCST_C_TGRP_ADD_TGT_FAIL if (!defined($group) ||
+					    !defined($tgroup) ||
+					    !defined($tgt));
 
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
@@ -1908,21 +1835,27 @@ sub addTargetGroupTarget {
 	$cmd .= "add $tgt";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_TGRP_ADD_TGT_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->deviceGroupExists($group);
+	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_TGRP_ADD_TGT_FAIL;
+	$rc = $self->targetGroupExists($group, $tgroup);
+	return SCST_C_DGRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetGroupTargetExists($group, $tgroup, $tgt);
+	return $rc == TRUE ? SCST_C_TGRP_TGT_EXISTS : $rc > 1 ? $rc : SCST_C_TGRP_ADD_TGT_FAIL;
 }
 
 sub removeDeviceGroupDevice {
@@ -1932,6 +1865,28 @@ sub removeDeviceGroupDevice {
 
 	return SCST_C_DGRP_REM_DEV_FAIL if (!defined($group) || !defined($device));
 
+	my ($path, $cmd);
+	if (new_sysfs_interface()) {
+		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
+		$cmd = "in " . make_path(IN_SCST_DEV_GROUPS, $group,
+					 SCST_DG_DEVICES) . " ";
+	} else {
+		$path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_DEVICES, SCST_MGMT_IO);
+	}
+	$cmd .= "del $device";
+
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->deviceGroupExists($group);
 	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
 	return $rc if ($rc > 1);
@@ -1944,31 +1899,6 @@ sub removeDeviceGroupDevice {
 	return SCST_C_DGRP_NO_DEVICE if (!$rc);
 	return $rc if ($rc > 1);
 
-	my ($path, $cmd);
-	if (new_sysfs_interface()) {
-		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
-		$cmd = "in " . make_path(IN_SCST_DEV_GROUPS, $group,
-					 SCST_DG_DEVICES) . " ";
-	} else {
-		$path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_DEVICES, SCST_MGMT_IO);
-	}
-	$cmd .= "del $device";
-
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DGRP_REM_DEV_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_DGRP_REM_DEV_FAIL;
 }
 
@@ -1979,14 +1909,6 @@ sub removeTargetGroup {
 
 	return SCST_C_DGRP_REM_GRP_FAIL if (!defined($group) || !defined($tgroup));
 
-	my $rc = $self->deviceGroupExists($group);
-	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetGroupExists($group, $tgroup);
-	return SCST_C_DGRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -1998,20 +1920,25 @@ sub removeTargetGroup {
 	$cmd .= "del $tgroup";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DGRP_REM_GRP_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->deviceGroupExists($group);
+	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetGroupExists($group, $tgroup);
+	return SCST_C_DGRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_DGRP_REM_GRP_FAIL;
 }
 
@@ -2023,18 +1950,6 @@ sub removeTargetGroupTarget {
 
 	return SCST_C_TGRP_REM_TGT_FAIL if (!defined($group) || !defined($tgroup) || !defined($tgt));
 
-	my $rc = $self->deviceGroupExists($group);
-	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetGroupExists($group, $tgroup);
-	return SCST_C_DGRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetGroupTargetExists($group, $tgroup, $tgt);
-	return SCST_C_TGRP_NO_TGT if (!$rc);
-	return $rc if ($rc > 1);
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -2047,20 +1962,29 @@ sub removeTargetGroupTarget {
 	$cmd .= "del $tgt";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_TGRP_REM_TGT_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->deviceGroupExists($group);
+	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetGroupExists($group, $tgroup);
+	return SCST_C_DGRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetGroupTargetExists($group, $tgroup, $tgt);
+	return SCST_C_TGRP_NO_TGT if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_TGRP_REM_TGT_FAIL;
 }
 
@@ -2075,22 +1999,6 @@ sub addInitiator {
 	    if (!defined($driver) || !defined($target) ||
 		!defined($group) || !defined($initiator));
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->groupExists($driver, $target, $group);
-	return SCST_C_GRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->initiatorExists($driver, $target, $group, $initiator);
-	return SCST_C_GRP_INI_EXISTS if ($rc == TRUE);
-	return $rc if ($rc > 1);
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -2105,30 +2013,17 @@ sub addInitiator {
 	$cmd .= "add $initiator";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_GRP_ADD_INI_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_GRP_ADD_INI_FAIL;
-}
-
-sub removeInitiator {
-	my $self = shift;
-	my $driver = shift;
-	my $target = shift;
-	my $group = shift;
-	my $initiator = shift;
-
 	return SCST_C_GRP_REM_INI_FAIL if (!defined($driver) ||
 					   !defined($target) ||
 					   !defined($initiator));
@@ -2146,9 +2041,21 @@ sub removeInitiator {
 	return $rc if ($rc > 1);
 
 	$rc = $self->initiatorExists($driver, $target, $group, $initiator);
-	return SCST_C_GRP_NO_INI if (!$rc);
+	return SCST_C_GRP_INI_EXISTS if ($rc == TRUE);
 	return $rc if ($rc > 1);
 
+	return SCST_C_GRP_ADD_INI_FAIL;
+}
+
+sub removeInitiator {
+	my $self = shift;
+	my $driver = shift;
+	my $target = shift;
+	my $group = shift;
+	my $initiator = shift;
+
+	return SCST_C_GRP_REM_INI_FAIL if (!defined($driver) || !defined($target) || !defined($group) || !defined($initiator));
+
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -2163,20 +2070,33 @@ sub removeInitiator {
 	$cmd .= "del $initiator";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_GRP_REM_INI_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetExists($driver, $target);
+	return SCST_C_TGT_NO_TARGET if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->groupExists($driver, $target, $group);
+	return SCST_C_GRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->initiatorExists($driver, $target, $group, $initiator);
+	return SCST_C_GRP_NO_INI if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_GRP_REM_INI_FAIL;
 }
 
@@ -2188,6 +2108,31 @@ sub moveInitiator {
 	my $to = shift;
 	my $initiator = shift;
 
+	my ($path, $cmd);
+	if (new_sysfs_interface()) {
+		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
+		$cmd = "in " . make_path(IN_SCST_TARGETS, $driver, $target,
+					 SCST_GROUPS, $from, SCST_INITIATORS) .
+					     " ";
+	} else {
+		$path = make_path(SCST_TARGETS_DIR(), $driver, $target,
+				  SCST_GROUPS, $from, SCST_INITIATORS,
+				  SCST_MGMT_IO);
+	}
+	$cmd .= "move $initiator $to";
+
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->driverExists($driver);
 	return SCST_C_DRV_NO_DRIVER if (!$rc);
 	return $rc if ($rc > 1);
@@ -2212,34 +2157,6 @@ sub moveInitiator {
 	return SCST_C_GRP_INI_EXISTS if ($rc == TRUE);
 	return $rc if ($rc > 1);
 
-	my ($path, $cmd);
-	if (new_sysfs_interface()) {
-		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
-		$cmd = "in " . make_path(IN_SCST_TARGETS, $driver, $target,
-					 SCST_GROUPS, $from, SCST_INITIATORS) .
-					     " ";
-	} else {
-		$path = make_path(SCST_TARGETS_DIR(), $driver, $target,
-				  SCST_GROUPS, $from, SCST_INITIATORS,
-				  SCST_MGMT_IO);
-	}
-	$cmd .= "move $initiator $to";
-
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_GRP_MOV_INI_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_GRP_MOV_INI_FAIL;
 }
 
@@ -2249,18 +2166,6 @@ sub clearInitiators {
 	my $target = shift;
 	my $group = shift;
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->groupExists($driver, $target, $group);
-	return SCST_C_GRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -2275,20 +2180,29 @@ sub clearInitiators {
 	$cmd .= "clear";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_GRP_CLR_INI_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetExists($driver, $target);
+	return SCST_C_TGT_NO_TARGET if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->groupExists($driver, $target, $group);
+	return SCST_C_GRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_GRP_CLR_INI_FAIL;
 }
 
@@ -2308,41 +2222,6 @@ sub addLun {
 			!defined($device) || !defined($lun) ||
 			!defined($attributes));
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->deviceOpen($device);
-	return SCST_C_DEV_NO_DEVICE if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->checkLunCreateAttributes($driver, $target, $attributes, $group);
-	return SCST_C_LUN_BAD_ATTRIBUTES if ($rc == TRUE);
-	return $rc if ($rc > 1);
-
-	my $err2;
-
-	if (defined($group)) {
-		$rc = $self->groupExists($driver, $target, $group);
-		return SCST_C_GRP_NO_GROUP if (!$rc);
-		return $rc if ($rc > 1);
-
-		$err  = SCST_C_GRP_ADD_LUN_FAIL;
-		$err2 = SCST_C_GRP_LUN_EXISTS;
-
-	} else {
-		$err  = SCST_C_TGT_ADD_LUN_FAIL;
-		$err2 = SCST_C_TGT_LUN_EXISTS;
-	}
-
-	$rc = $self->lunExists($driver, $target, $lun, $group);
-	return $err2 if ($rc == TRUE);
-	return $rc if ($rc > 1);
-
 	my $o_string = "";
 	foreach my $attribute (keys %{$attributes}) {
 		my $value = $$attributes{$attribute};
@@ -2376,20 +2255,44 @@ sub addLun {
 	$cmd .= "add $device $lun $o_string";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return $err if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	if (defined($group)) {
+		my $rc = $self->groupExists($driver, $target, $group);
+		return SCST_C_GRP_NO_GROUP if (!$rc);
+		return $rc if ($rc > 1);
+	}
+
+	my $rc = $self->lunExists($driver, $target, $lun, $group);
+	return (defined($group) ? SCST_C_GRP_LUN_EXISTS :
+		SCST_C_TGT_LUN_EXISTS) if ($rc == TRUE);
+	return $rc if ($rc > 1);
+
+	$rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetExists($driver, $target);
+	return SCST_C_TGT_NO_TARGET if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->deviceOpen($device);
+	return SCST_C_DEV_NO_DEVICE if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->checkLunCreateAttributes($driver, $target, $attributes, $group);
+	return SCST_C_LUN_BAD_ATTRIBUTES if ($rc == TRUE);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return $err;
 }
 
@@ -2403,33 +2306,8 @@ sub removeLun {
 	my $err = defined($group) ? SCST_C_GRP_REM_LUN_FAIL :
 	    SCST_C_TGT_ADD_LUN_FAIL;
 
-	return $err if (!defined($driver) || !defined($target) || !defined($lun));
-
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	my $err2;
-
-	if (defined($group)) {
-		$rc = $self->groupExists($driver, $target, $group);
-		return SCST_C_GRP_NO_GROUP if (!$rc);
-		return $rc if ($rc > 1);
-
-		$err2 = SCST_C_GRP_NO_LUN;
-	} else {
-		$err2 = SCST_C_TGT_NO_LUN;
-	}
-
-	return $err if (!defined($lun));
-
-	$rc = $self->lunExists($driver, $target, $lun, $group);
-	return $err2 if (!$rc);
-	return $rc if ($rc > 1);
+	return $err if (!defined($driver) || !defined($target) ||
+			!defined($lun));
 
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
@@ -2455,20 +2333,36 @@ sub removeLun {
 	$cmd .= "del $lun";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return $err if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->targetExists($driver, $target);
+	return SCST_C_TGT_NO_TARGET if (!$rc);
+	return $rc if ($rc > 1);
+
+	if (defined($group)) {
+		$rc = $self->groupExists($driver, $target, $group);
+		return SCST_C_GRP_NO_GROUP if (!$rc);
+		return $rc if ($rc > 1);
+	}
+
+	$rc = $self->lunExists($driver, $target, $lun, $group);
+	return (defined($group) ? SCST_C_GRP_NO_LUN : SCST_C_TGT_NO_LUN)
+	    if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
 	return $err;
 }
 
@@ -2551,20 +2445,17 @@ sub replaceLun {
 	$cmd .= "replace $device $lun $o_string";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_LUN_RPL_DEV_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_LUN_RPL_DEV_FAIL;
 }
 
@@ -2579,20 +2470,6 @@ sub clearLuns {
 
 	return $err if (!defined($driver) || !defined($target));
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	if (defined($group)) {
-		$rc = $self->groupExists($driver, $target, $group);
-		return SCST_C_GRP_NO_GROUP if (!$rc);
-		return $rc if ($rc > 1);
-	}
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -2617,21 +2494,32 @@ sub clearLuns {
 	$cmd .= "clear";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return $err if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_GRP_CLR_LUN_FAIL;
+	$rc = $self->targetExists($driver, $target);
+	return SCST_C_TGT_NO_TARGET if (!$rc);
+	return $rc if ($rc > 1);
+
+	if (defined($group)) {
+		$rc = $self->groupExists($driver, $target, $group);
+		return SCST_C_GRP_NO_GROUP if (!$rc);
+		return $rc if ($rc > 1);
+	}
+
+	return $err;
 }
 
 sub deviceHandler {
@@ -2695,15 +2583,14 @@ sub deviceAttributes {
 	my $device = shift;
 	my %attributes;
 
-	if ($self->deviceOpen($device) != TRUE) {
-		$self->{'err_string'} = "deviceAttributes(): Device '$device' is not open";
-		return undef;
-	}
-
 	my $pHandle = new IO::Handle;
 	my $_path = make_path(SCST_DEVICES_DIR(), $device);
 	if (!(opendir $pHandle, $_path)) {
-		$self->{'err_string'} = "deviceAttributes(): Unable to read directory '$_path': $!";
+		if ($self->deviceOpen($device) != TRUE) {
+			$self->{'err_string'} = "deviceAttributes(): Device '$device' is not open";
+		} else {
+			$self->{'err_string'} = "deviceAttributes(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -2739,6 +2626,7 @@ sub deviceAttributes {
 
 				$attributes{$attribute}->{'static'} = TRUE;
 			}
+			close $eHandle;
 		} elsif ($attribute eq 'handler') {
 			my $linked = readlink $pPath;
 
@@ -2776,7 +2664,7 @@ sub deviceAttributes {
 				}
 
 				my ($value, $is_key) = split("\n", _sysread($io) , 2);
-
+				close $io;
 				chomp $value;
 
 				$is_key = new_sysfs_interface() &&
@@ -2811,6 +2699,8 @@ sub deviceAttributes {
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
@@ -2819,15 +2709,14 @@ sub driverAttributes {
 	my $driver = shift;
 	my %attributes;
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "driverAttributes(): Driver '$driver' is not available";
-		return undef;
-	}
-
 	my $pHandle = new IO::Handle;
 	my $_path = make_path(SCST_TARGETS_DIR(), $driver);
 	if (!(opendir $pHandle, $_path)) {
-		$self->{'err_string'} = "driverAttributes(): Unable to read directory '$_path': $!";
+		if ($self->driverExists($driver) != TRUE) {
+			$self->{'err_string'} = "driverAttributes(): Driver '$driver' is not available";
+		} else {
+			$self->{'err_string'} = "driverAttributes(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -2903,12 +2792,15 @@ sub driverAttributes {
 						$attributes{$attribute}->{'value'} = $value;
 					}
 				}
+				close $io;
 
 				$attributes{$attribute}->{'static'} = $is_static;
 			}
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
@@ -2918,35 +2810,28 @@ sub setDriverAttribute {
 	my $attribute = shift;
 	my $value = shift;
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
 	return TRUE if (!defined($attribute) || !defined($value));
 
-	my $attributes = $self->driverAttributes($driver);
-
-	return SCST_C_DRV_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
-	return SCST_C_DRV_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
-
 	my $path = make_path(SCST_TARGETS_DIR(), $driver, $attribute);
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DRV_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $attribute = $value\n";
-	} else {
-		$bytes = _syswrite($io, $value, length($value));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $attribute = $value\n";
+		} else {
+			$bytes = _syswrite($io, $value, length($value));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_DRV_SETATTR_FAIL;
+	return setAttrFailed($path, SCST_C_DRV_BAD_ATTRIBUTES,
+			     SCST_C_DRV_ATTRIBUTE_STATIC);
 }
 
 sub targetAttributes {
@@ -2957,20 +2842,16 @@ sub targetAttributes {
 
 	return undef if (!defined($driver) || !defined($target));
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "targetAttributes(): Driver '$driver' is not available";
-		return undef;
-	}
-
-	if ($self->targetExists($driver, $target) != TRUE) {
-		$self->{'err_string'} = "targetAttributes(): Target '$target' is not available";
-		return undef;
-	}
-
 	my $pHandle = new IO::Handle;
 	my $_path = make_path(SCST_TARGETS_DIR(), $driver, $target);
 	if (!(opendir $pHandle, $_path)) {
-		$self->{'err_string'} = "targetAttributes(): Unable to read directory '$_path': $!";
+		if ($self->driverExists($driver) != TRUE) {
+			$self->{'err_string'} = "targetAttributes(): Driver '$driver' is not available";
+		} elsif ($self->targetExists($driver, $target) != TRUE) {
+			$self->{'err_string'} = "targetAttributes(): Target '$target' is not available";
+		} else {
+			$self->{'err_string'} = "targetAttributes(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -3028,6 +2909,7 @@ sub targetAttributes {
 				chomp $value if (defined($value));
 
 				my $is_key = <$io>;
+				close $io;
 				$is_key = new_sysfs_interface() && !$is_static ||
 				    $is_key && $is_key =~ /\[key\]/;
 
@@ -3052,6 +2934,8 @@ sub targetAttributes {
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
@@ -3062,21 +2946,8 @@ sub setTargetAttribute {
 	my $attribute = shift;
 	my $value = shift;
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
 	return TRUE if (!defined($attribute) || !defined($value));
 
-	my $attributes = $self->targetAttributes($driver, $target);
-
-	return SCST_C_TGT_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
-	return SCST_C_TGT_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
-
 	my ($path, $cmd);
 	if (new_sysfs_interface() &&
 	    ($attribute eq 'enabled' || $attribute eq 'cpu_mask')) {
@@ -3092,21 +2963,27 @@ sub setTargetAttribute {
 	}
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_TGT_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $cmd > $path\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $cmd > $path\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_TGT_SETATTR_FAIL;
+	$rc = $self->targetExists($driver, $target);
+	return SCST_C_TGT_NO_TARGET if (!$rc);
+	return $rc if ($rc > 1);
+
+	return setAttrFailed($path, SCST_C_TGT_BAD_ATTRIBUTES,
+			     SCST_C_TGT_ATTRIBUTE_STATIC);
 }
 
 sub groupAttributes {
@@ -3116,26 +2993,19 @@ sub groupAttributes {
 	my $group = shift;
 	my %attributes;
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "groupAttributes(): Driver '$driver' is not available";
-		return undef;
-	}
-
-	if ($self->targetExists($driver, $target) != TRUE) {
-		$self->{'err_string'} = "groupAttributes(): Target '$target' is not available";
-		return undef;
-	}
-
-	if ($self->groupExists($driver, $target, $group) != TRUE) {
-		$self->{'err_string'} = "groupAttributes(): Group '$group' does not exist";
-		return undef;
-	}
-
 	my $pHandle = new IO::Handle;
 	my $_path = make_path(SCST_TARGETS_DIR(), $driver, $target, SCST_GROUPS,
 			      $group);
 	if (!(opendir $pHandle, $_path)) {
-		$self->{'err_string'} = "groupAttributes(): Unable to read directory '$_path': $!";
+		if ($self->driverExists($driver) != TRUE) {
+			$self->{'err_string'} = "groupAttributes(): Driver '$driver' is not available";
+		} elsif ($self->targetExists($driver, $target) != TRUE) {
+			$self->{'err_string'} = "groupAttributes(): Target '$target' is not available";
+		} elsif ($self->groupExists($driver, $target, $group) != TRUE) {
+			$self->{'err_string'} = "groupAttributes(): Group '$group' does not exist";
+		} else {
+			$self->{'err_string'} = "groupAttributes(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -3173,6 +3043,7 @@ sub groupAttributes {
 				chomp $value;
 
 				my $is_key = <$io>;
+				close $io;
 				$is_key = new_sysfs_interface() && !$is_static ||
 				    $is_key && $is_key =~ /\[key\]/;
 
@@ -3197,6 +3068,8 @@ sub groupAttributes {
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
@@ -3208,25 +3081,8 @@ sub setGroupAttribute {
 	my $attribute = shift;
 	my $value = shift;
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->groupExists($driver, $target, $group);
-	return SCST_C_GRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
 	return TRUE if (!defined($attribute) || !defined($value));
 
-	my $attributes = $self->groupAttributes($driver, $target, $group);
-
-	return SCST_C_GRP_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
-	return SCST_C_GRP_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
-
 	my ($path, $cmd);
 	if (new_sysfs_interface() && $attribute eq 'cpu_mask') {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -3240,21 +3096,31 @@ sub setGroupAttribute {
 	$cmd .= $value;
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_GRP_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $cmd > $path\n";
-	} else {
-		$bytes = _syswrite($io, $value, length($value));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $cmd > $path\n";
+		} else {
+			$bytes = _syswrite($io, $value, length($value));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->driverExists($driver);
+	return SCST_C_DRV_NO_DRIVER if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_GRP_SETATTR_FAIL;
+	$rc = $self->targetExists($driver, $target);
+	return SCST_C_TGT_NO_TARGET if (!$rc);
+	return $rc if ($rc > 1);
+
+	$rc = $self->groupExists($driver, $target, $group);
+	return SCST_C_GRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
+
+	return setAttrFailed($path, SCST_C_GRP_BAD_ATTRIBUTES,
+			     SCST_C_GRP_ATTRIBUTE_STATIC);
 }
 
 sub lunAttributes {
@@ -3265,24 +3131,9 @@ sub lunAttributes {
 	my $group = shift;
 	my %attributes;
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "lunAttributes(): Driver '$driver' is not available";
-		return undef;
-	}
-
-	if ($self->targetExists($driver, $target) != TRUE) {
-		$self->{'err_string'} = "lunAttributes(): Target '$target' is not available";
-		return undef;
-	}
-
 	my ($_path, $luncrattr);
 
 	if (defined($group)) {
-		if ($self->groupExists($driver, $target, $group) != TRUE) {
-			$self->{'err_string'} = "lunAttributes(): Group '$group' does not exist";
-			return undef;
-		}
-
 		$_path = make_path(SCST_TARGETS_DIR(), $driver, $target,
 				   SCST_GROUPS, $group, SCST_LUNS, $lun);
 		$luncrattr = $self->lunCreateAttributes($driver, $target,
@@ -3293,14 +3144,19 @@ sub lunAttributes {
 		$luncrattr = $self->lunCreateAttributes($driver, $target);
 	}
 
-	if ($self->lunExists($driver, $target, $lun, $group) != TRUE) {
-		$self->{'err_string'} = "lunAttributes(): LUN '$lun' does not exist";
-		return undef;
-	}
-
 	my $pHandle = new IO::Handle;
 	if (!(opendir $pHandle, $_path)) {
-		$self->{'err_string'} = "lunAttributes(): Unable to read directory '$_path': $!";
+		if ($self->driverExists($driver) != TRUE) {
+			$self->{'err_string'} = "lunAttributes(): Driver '$driver' is not available";
+		} elsif ($self->targetExists($driver, $target) != TRUE) {
+			$self->{'err_string'} = "lunAttributes(): Target '$target' is not available";
+		} elsif (defined($group) && $self->groupExists($driver, $target, $group) != TRUE) {
+			$self->{'err_string'} = "lunAttributes(): Group '$group' does not exist";
+		} elsif ($self->lunExists($driver, $target, $lun, $group) != TRUE) {
+			$self->{'err_string'} = "lunAttributes(): LUN '$lun' does not exist";
+		} else {
+			$self->{'err_string'} = "lunAttributes(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -3342,6 +3198,7 @@ sub lunAttributes {
 				chomp $value;
 
 				my $is_key = <$io>;
+				close $io;
 				$is_key = new_sysfs_interface() &&
 				    (!$is_static ||
 				     defined($$luncrattr{$attribute})) ||
@@ -3368,6 +3225,8 @@ sub lunAttributes {
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
@@ -3384,6 +3243,29 @@ sub setLunAttribute {
 	    if (!defined($driver) || !defined($target) || !defined($lun) ||
 		!defined($attribute) || !defined($value));
 
+	my $path;
+
+	if (defined($group)) {
+		$path = make_path(SCST_TARGETS_DIR(), $driver, $target,
+				  SCST_GROUPS, $group, SCST_LUNS, $lun,
+				  $attribute);
+	} else {
+		$path = make_path(SCST_TARGETS_DIR(), $driver, $target,
+				  SCST_LUNS, $lun, $attribute);
+	}
+
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $attribute = $value\n";
+		} else {
+			$bytes = _syswrite($io, $value, length($value));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->driverExists($driver);
 	return SCST_C_DRV_NO_DRIVER if (!$rc);
 	return $rc if ($rc > 1);
@@ -3392,19 +3274,10 @@ sub setLunAttribute {
 	return SCST_C_TGT_NO_TARGET if (!$rc);
 	return $rc if ($rc > 1);
 
-	my $path;
-
 	if (defined($group)) {
 		$rc = $self->groupExists($driver, $target, $group);
 		return SCST_C_GRP_NO_GROUP if (!$rc);
 		return $rc if ($rc > 1);
-
-		$path = make_path(SCST_TARGETS_DIR(), $driver, $target,
-				  SCST_GROUPS, $group, SCST_LUNS, $lun,
-				  $attribute);
-	} else {
-		$path = make_path(SCST_TARGETS_DIR(), $driver, $target,
-				  SCST_LUNS, $lun, $attribute);
 	}
 
 	$rc = $self->lunExists($driver, $target, $lun, $group);
@@ -3417,21 +3290,6 @@ sub setLunAttribute {
 	return SCST_C_LUN_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
 	return SCST_C_LUN_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
 
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_LUN_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $attribute = $value\n";
-	} else {
-		$bytes = _syswrite($io, $value, length($value));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_LUN_SETATTR_FAIL;
 }
 
@@ -3443,31 +3301,21 @@ sub initiatorAttributes {
 	my $initiator = shift;
 	my %attributes;
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "initiatorAttributes(): Driver '$driver' is not available";
-		return undef;
-	}
-
-	if ($self->targetExists($driver, $target) != TRUE) {
-		$self->{'err_string'} = "initiatorAttributes(): Target '$target' is not available";
-		return undef;
-	}
-
-	if ($self->groupExists($driver, $target, $group) != TRUE) {
-		$self->{'err_string'} = "initiatorAttributes(): Group '$group' does not exist";
-		return undef;
-	}
-
-	if ($self->initiatorExists($driver, $target, $group, $initiator) != TRUE) {
-		$self->{'err_string'} = "initiatorAttributes(): Initiator '$initiator' does not exist";
-		return undef;
-	}
-
 	my $pHandle = new IO::Handle;
 	my $_path = make_path(SCST_TARGETS_DIR(), $driver, $target, SCST_GROUPS,
 			      $group, SCST_INITIATORS, $initiator);
 	if (!(opendir $pHandle, $_path)) {
-		$self->{'err_string'} = "initiatorAttributes(): Unable to read directory '$_path': $!";
+		if ($self->driverExists($driver) != TRUE) {
+			$self->{'err_string'} = "initiatorAttributes(): Driver '$driver' is not available";
+		} elsif ($self->targetExists($driver, $target) != TRUE) {
+			$self->{'err_string'} = "initiatorAttributes(): Target '$target' is not available";
+		} elsif ($self->groupExists($driver, $target, $group) != TRUE) {
+			$self->{'err_string'} = "initiatorAttributes(): Group '$group' does not exist";
+		} elsif ($self->initiatorExists($driver, $target, $group, $initiator) != TRUE) {
+			$self->{'err_string'} = "initiatorAttributes(): Initiator '$initiator' does not exist";
+		} else {
+			$self->{'err_string'} = "initiatorAttributes(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -3504,6 +3352,7 @@ sub initiatorAttributes {
 				chomp $value;
 
 				my $is_key = <$io>;
+				close $io;
 				$is_key = new_sysfs_interface() && !$is_static ||
 				    $is_key && $is_key =~ /\[key\]/;
 
@@ -3528,6 +3377,8 @@ sub initiatorAttributes {
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
@@ -3540,6 +3391,23 @@ sub setInitiatorAttribute {
 	my $attribute = shift;
 	my $value = shift;
 
+	return TRUE if (!defined($attribute) || !defined($value));
+
+	my $path = make_path(SCST_TARGETS_DIR(), $driver, $target, SCST_GROUPS,
+			     $group, SCST_LUNS, $initiator, $attribute);
+
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $attribute = $value\n";
+		} else {
+			$bytes = _syswrite($io, $value, length($value));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->driverExists($driver);
 	return SCST_C_DRV_NO_DRIVER if (!$rc);
 	return $rc if ($rc > 1);
@@ -3556,31 +3424,6 @@ sub setInitiatorAttribute {
 	return SCST_C_GRP_NO_INI if (!$rc);
 	return $rc if ($rc > 1);
 
-	return TRUE if (!defined($attribute) || !defined($value));
-
-	my $attributes = $self->initiatorAttributes($driver, $target, $group, $initiator);
-
-	return SCST_C_INI_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
-	return SCST_C_INI_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
-
-	my $path = make_path(SCST_TARGETS_DIR(), $driver, $target, SCST_GROUPS,
-			     $group, SCST_LUNS, $initiator, $attribute);
-
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_INI_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $attribute = $value\n";
-	} else {
-		$bytes = _syswrite($io, $value, length($value));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_INI_SETATTR_FAIL;
 }
 
@@ -3589,15 +3432,14 @@ sub deviceGroupAttributes {
 	my $group = shift;
 	my %attributes;
 
-	if ($self->deviceGroupExists($group) != TRUE) {
-		$self->{'err_string'} = "targetGroupAttributes(): Device group '$group' does not exist";
-		return undef;
-	}
-
 	my $pHandle = new IO::Handle;
 	my $_path = make_path(SCST_DEV_GROUP_DIR(), $group);
 	if (!(opendir $pHandle, $_path)) {
-		$self->{'err_string'} = "deviceGroupAttributes(): Unable to read directory '$_path': $!";
+		if ($self->deviceGroupExists($group) != TRUE) {
+			$self->{'err_string'} = "deviceGroupAttributes(): Device group '$group' does not exist";
+		} else {
+			$self->{'err_string'} = "deviceGroupAttributes(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -3632,6 +3474,7 @@ sub deviceGroupAttributes {
 				chomp $value;
 
 				my $is_key = <$io>;
+				close $io;
 				$is_key = new_sysfs_interface() && !$is_static ||
 				    $is_key && $is_key =~ /\[key\]/;
 
@@ -3656,6 +3499,8 @@ sub deviceGroupAttributes {
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
@@ -3665,20 +3510,16 @@ sub targetGroupAttributes {
 	my $tgroup = shift;
 	my %attributes;
 
-	if ($self->deviceGroupExists($group) != TRUE) {
-		$self->{'err_string'} = "targetGroupAttributes(): Device group '$group' does not exist";
-		return undef;
-	}
-
-	if ($self->targetGroupExists($group, $tgroup) != TRUE) {
-		$self->{'err_string'} = "targetGroupAttributes(): Target Group '$tgroup' does not exist";
-		return undef;
-	}
-
 	my $pHandle = new IO::Handle;
 	my $_path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_TGROUPS, $tgroup);
 	if (!(opendir $pHandle, $_path)) {
-		$self->{'err_string'} = "targetGroupAttributes(): Unable to read directory '$_path': $!";
+		if ($self->deviceGroupExists($group) != TRUE) {
+			$self->{'err_string'} = "targetGroupAttributes(): Device group '$group' does not exist";
+		} elsif ($self->targetGroupExists($group, $tgroup) != TRUE) {
+			$self->{'err_string'} = "targetGroupAttributes(): Target Group '$tgroup' does not exist";
+		} else {
+			$self->{'err_string'} = "targetGroupAttributes(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -3713,6 +3554,7 @@ sub targetGroupAttributes {
 				chomp $value;
 
 				my $is_key = <$io>;
+				close $io;
 				$is_key = new_sysfs_interface() && !$is_static ||
 				    $is_key && $is_key =~ /\[key\]/;
 
@@ -3737,6 +3579,8 @@ sub targetGroupAttributes {
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
@@ -3747,21 +3591,6 @@ sub targetGroupTargetAttributes {
 	my $tgt = shift;
 	my %attributes;
 
-	if ($self->deviceGroupExists($group) != TRUE) {
-		$self->{'err_string'} = "targetGroupTargetAttributes(): Device group '$group' does not exist";
-		return undef;
-	}
-
-	if ($self->targetGroupExists($group, $tgroup) != TRUE) {
-		$self->{'err_string'} = "targetGroupTargetAttributes(): Target Group '$tgroup' does not exist";
-		return undef;
-	}
-
-	if ($self->targetGroupTargetExists($group, $tgroup, $tgt) != TRUE) {
-		$self->{'err_string'} = "targetGroupTargetAttributes(): Target '$tgt' does not exist";
-		return undef;
-	}
-
 	my $pHandle = new IO::Handle;
 	my $_path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_TGROUPS, $tgroup, $tgt);
 	if (-l $_path) {
@@ -3769,7 +3598,15 @@ sub targetGroupTargetAttributes {
 	}
 
 	if (!(opendir $pHandle, $_path)) {
-		$self->{'err_string'} = "targetGroupTargetAttributes(): Unable to read directory '$_path': $!";
+		if ($self->deviceGroupExists($group) != TRUE) {
+			$self->{'err_string'} = "targetGroupTargetAttributes(): Device group '$group' does not exist";
+		} elsif ($self->targetGroupExists($group, $tgroup) != TRUE) {
+			$self->{'err_string'} = "targetGroupTargetAttributes(): Target Group '$tgroup' does not exist";
+		} elsif ($self->targetGroupTargetExists($group, $tgroup, $tgt) != TRUE) {
+			$self->{'err_string'} = "targetGroupTargetAttributes(): Target '$tgt' does not exist";
+		} else {
+			$self->{'err_string'} = "targetGroupTargetAttributes(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -3805,6 +3642,7 @@ sub targetGroupTargetAttributes {
 				chomp $value;
 
 				my $is_key = <$io>;
+				close $io;
 				$is_key = new_sysfs_interface() && !$is_static ||
 				    $is_key && $is_key =~ /\[key\]/;
 
@@ -3829,6 +3667,8 @@ sub targetGroupTargetAttributes {
 		}
 	}
 
+	close $pHandle;
+
 	return \%attributes;
 }
 
@@ -3839,27 +3679,21 @@ sub setAluaAttribute {
 
 	return TRUE if (!defined($attribute) || !defined($value));
 
-	my $attributes = $self->aluaAttributes();
-
-	return SCST_C_ALUA_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
-	return SCST_C_ALUA_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
-
 	my $path = make_path(SCST_DEV_GROUP_DIR(), $attribute);
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_ALUA_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $value > $path\n";
-	} else {
-		$bytes = _syswrite($io, $value, length($value));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $value > $path\n";
+		} else {
+			$bytes = _syswrite($io, $value, length($value));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
-
-	return ($self->{'debug'} || $bytes) ? 0 : SCST_C_ALUA_SETATTR_FAIL;
+	return setAttrFailed($path, SCST_C_ALUA_BAD_ATTRIBUTES,
+			     SCST_C_ALUA_ATTRIBUTE_STATIC);
 }
 
 sub setDeviceGroupAttribute {
@@ -3868,35 +3702,28 @@ sub setDeviceGroupAttribute {
 	my $attribute = shift;
 	my $value = shift;
 
-	my $rc = $self->deviceGroupExists($group);
-	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
 	return TRUE if (!defined($attribute) || !defined($value));
 
-	my $attributes = $self->deviceGroupAttributes($group);
-
-	return SCST_C_DGRP_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
-	return SCST_C_DGRP_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
-
 	my $path = make_path(SCST_DEV_GROUP_DIR(), $group, $attribute);
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DGRP_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $attribute = $value\n";
-	} else {
-		$bytes = _syswrite($io, $value, length($value));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $attribute = $value\n";
+		} else {
+			$bytes = _syswrite($io, $value, length($value));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->deviceGroupExists($group);
+	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_DGRP_SETATTR_FAIL;
+	return setAttrFailed($path, SCST_C_DGRP_BAD_ATTRIBUTES,
+				     SCST_C_DGRP_ATTRIBUTE_STATIC);
 }
 
 sub setTargetGroupAttribute {
@@ -3909,6 +3736,20 @@ sub setTargetGroupAttribute {
 	return TRUE if (!defined($group) || !defined($tgroup) ||
 			!defined($attribute) || !defined($value));
 
+	my $path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_TGROUPS, $tgroup, $attribute);
+
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $attribute = $value\n";
+		} else {
+			$bytes = _syswrite($io, $value, length($value));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->deviceGroupExists($group);
 	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
 	return $rc if ($rc > 1);
@@ -3917,31 +3758,8 @@ sub setTargetGroupAttribute {
 	return SCST_C_DGRP_NO_GROUP if (!$rc);
 	return $rc if ($rc > 1);
 
-	return TRUE if (!defined($attribute) || !defined($value));
-
-	my $attributes = $self->targetGroupAttributes($group, $tgroup);
-
-	return SCST_C_TGRP_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
-	return SCST_C_TGRP_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
-
-	my $path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_TGROUPS, $tgroup, $attribute);
-
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_TGRP_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $attribute = $value\n";
-	} else {
-		$bytes = _syswrite($io, $value, length($value));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_TGRP_SETATTR_FAIL;
+	return setAttrFailed($path, SCST_C_TGRP_BAD_ATTRIBUTES,
+			     SCST_C_TGRP_ATTRIBUTE_STATIC);
 }
 
 sub setTargetGroupTargetAttribute {
@@ -3956,6 +3774,21 @@ sub setTargetGroupTargetAttribute {
 			!defined($tgt) || !defined($attribute) ||
 			!defined($value));
 
+	my $path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_TGROUPS,
+			     $tgroup, $tgt, $attribute);
+
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $attribute = $value\n";
+		} else {
+			$bytes = _syswrite($io, $value, length($value));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->deviceGroupExists($group);
 	return SCST_C_DEV_GRP_NO_GROUP if (!$rc);
 	return $rc if ($rc > 1);
@@ -3968,30 +3801,8 @@ sub setTargetGroupTargetAttribute {
 	return SCST_C_TGRP_NO_TGT if (!$rc);
 	return $rc if ($rc > 1);
 
-	my $attributes = $self->targetGroupTargetAttributes($group, $tgroup, $tgt);
-
-	return SCST_C_TGRP_TGT_BAD_ATTR if (!defined($$attributes{$attribute}));
-	return SCST_C_TGRP_TGT_ATTR_STATIC if ($$attributes{$attribute}->{'static'});
-
-	my $path = make_path(SCST_DEV_GROUP_DIR(), $group, SCST_DG_TGROUPS,
-			     $tgroup, $tgt, $attribute);
-
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_TGRP_TGT_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $attribute = $value\n";
-	} else {
-		$bytes = _syswrite($io, $value, length($value));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_TGRP_TGT_SETATTR_FAIL;
+	return setAttrFailed($path, SCST_C_TGRP_TGT_BAD_ATTR,
+			     SCST_C_TGRP_TGT_ATTR_STATIC);
 }
 
 sub handlers {
@@ -4041,35 +3852,27 @@ sub setHandlerAttribute {
 	my $attribute = shift;
 	my $value = shift;
 
+	return TRUE if (!defined($attribute) || !defined($value));
+
+	my $path = make_path(SCST_HANDLERS_DIR(), $handler, $attribute);
+	my $io = new IO::File $path, O_WRONLY;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $path -> $attribute = $value\n";
+		} else {
+			$bytes = _syswrite($io, $value, length($value));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
+	}
+
 	my $rc = $self->handlerExists($handler);
 	return SCST_C_HND_NO_HANDLER if (!$rc);
 	return $rc if ($rc > 1);
 
-	return TRUE if (!defined($attribute) || !defined($value));
-
-	my $attributes = $self->handlerAttributes($handler);
-
-	return SCST_C_HND_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
-	return SCST_C_HND_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
-
-	my $path = make_path(SCST_HANDLERS_DIR(), $handler, $attribute);
-
-	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_HND_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $path -> $attribute = $value\n";
-	} else {
-		$bytes = _syswrite($io, $value, length($value));
-	}
-
-	close $io;
-
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_HND_SETATTR_FAIL;
+	return setAttrFailed($path, SCST_C_HND_BAD_ATTRIBUTES,
+			     SCST_C_HND_ATTRIBUTE_STATIC);
 }
 
 sub handlerAttributes {
@@ -4077,17 +3880,16 @@ sub handlerAttributes {
 	my $handler = shift;
 	my %attributes;
 
-	if ($self->handlerExists($handler) != TRUE) {
-		$self->{'err_string'} = "handlerAttributes(): Handler '$handler' is not available";
-		return undef;
-	}
-
 	$attributes{'devices'}->{'value'} = devices($self, $handler);
 
 	my $hHandle = new IO::Handle;
 	my $_path = make_path(SCST_HANDLERS_DIR(), $handler);
 	if (!(opendir $hHandle, $_path)) {
-		$self->{'err_string'} = "handlerAttributes(): Unable to read directory '$_path': $!";
+		if ($self->handlerExists($handler) != TRUE) {
+			$self->{'err_string'} = "handlerAttributes(): Handler '$handler' is not available";
+		} else {
+			$self->{'err_string'} = "handlerAttributes(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -4173,6 +3975,8 @@ sub handlerAttributes {
 		close $io;
 	}
 
+	close $hHandle;
+
 	$attributes{'devices'}->{'static'} = TRUE;
 
 	return \%attributes;
@@ -4198,14 +4002,15 @@ sub handlerDeviceExists {
 	my $handler = shift;
 	my $device = shift;
 
-	my $rc = $self->handlerExists($handler);
-
-	return FALSE if (!$rc);
-	return $rc if ($rc > 1);
-
 	my $devices = $self->devicesByHandler($handler);
 
-	return SCST_C_FATAL_ERROR if (!defined($devices));
+	if (!defined($devices)) {
+		my $rc = $self->handlerExists($handler);
+		return FALSE if (!$rc);
+		return $rc if ($rc > 1);
+
+		return SCST_C_FATAL_ERROR;
+	}
 
 	foreach my $_device (@{$devices}) {
 		return TRUE if ($_device eq $device);
@@ -4218,14 +4023,15 @@ sub devicesByHandler {
 	my $self = shift;
 	my $handler = shift;
 
-	if ($self->handlerExists($handler) != TRUE) {
-		$self->{'err_string'} = "devicesByHandler(): Handler '$handler' is not available";
+	my $attributes = $self->handlerAttributes($handler);
+
+	if (!defined($attributes)) {
+		if ($self->handlerExists($handler) != TRUE) {
+			$self->{'err_string'} = "devicesByHandler(): Handler '$handler' is not available";
+		}
 		return undef;
 	}
 
-	my $attributes = $self->handlerAttributes($handler);
-
-	return undef if (!defined($attributes));
 	return \@{$$attributes{'devices'}->{'value'}};
 }
 
@@ -4236,13 +4042,14 @@ sub checkDeviceCreateAttributes {
 
 	return FALSE if (!defined($check));
 
-	my $rc = $self->handlerExists($handler);
-	return SCST_C_HND_NO_HANDLER if (!$rc);
-	return $rc if (!$rc > 1);
-
 	my $available = $self->deviceCreateAttributes($handler);
 
-	return SCST_C_FATAL_ERROR if (!defined($available));
+	if (!defined($available)) {
+		my $rc = $self->handlerExists($handler);
+		return SCST_C_HND_NO_HANDLER if (!$rc);
+		return $rc if (!$rc > 1);
+		return SCST_C_FATAL_ERROR;
+	}
 
 	if (ref($check) eq 'HASH') {
 		foreach my $attribute (keys %{$check}) {
@@ -4265,12 +4072,6 @@ sub deviceCreateAttributes {
 	my $available;
 	my %attributes;
 
-	if ($self->handlerExists($handler) != TRUE) {
-		$self->{'err_string'} = "deviceCreateAttributes(): Handler '$handler' ".
-		  "is not available";
-		return undef;
-	}
-
 	if (new_sysfs_interface()) {
 		my $io = new IO::File make_path(SCST_HANDLERS_DIR(), $handler,
 						SCST_ADD_DEV_PARAMS), O_RDONLY;
@@ -4279,13 +4080,19 @@ sub deviceCreateAttributes {
 			chomp($attribute);
 			$attributes{$attribute} = '';
 		}
+		close $io;
 	} else {
 		my $io = new IO::File make_path(SCST_HANDLERS_DIR(), $handler,
 						SCST_MGMT_IO), O_RDONLY;
 
 		if (!$io) {
-			$self->{'err_string'} = "deviceCreateAttributes(): Unable to open mgmt ".
-			    "interface for handler '$handler': $!";
+			if ($self->handlerExists($handler) != TRUE) {
+				$self->{'err_string'} = "deviceCreateAttributes(): Handler '$handler' ".
+				    "is not available";
+			} else {
+				$self->{'err_string'} = "deviceCreateAttributes(): Unable to open mgmt ".
+				    "interface for handler '$handler': $!";
+			}
 			return undef;
 		}
 
@@ -4295,6 +4102,7 @@ sub deviceCreateAttributes {
 				$available =~ s/\.$//;
 			}
 		}
+		close $io;
 
 		if ($available) {
 			foreach my $attribute (split(/\,/, $available)) {
@@ -4318,18 +4126,6 @@ sub openDevice {
 					!defined($device) ||
 					!defined($attributes));
 
-	my $rc = $self->handlerExists($handler);
-	return SCST_C_HND_NO_HANDLER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->checkDeviceCreateAttributes($handler, $attributes);
-	return SCST_C_DEV_BAD_ATTRIBUTES if ($rc == TRUE);
-	return $rc if ($rc > 1);
-
-	$rc = $self->handlerDeviceExists($handler, $device);
-	return SCST_C_DEV_EXISTS if ($rc == TRUE);
-	return $rc if ($rc > 1);
-
 	my $o_string = "";
 	foreach my $attribute (keys %{$attributes}) {
 		my $value = $$attributes{$attribute};
@@ -4348,23 +4144,36 @@ sub openDevice {
 	$cmd .= "add_device $device $o_string";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	if (!$io) {
-		$self->{'err_string'} = "openDevice(): Unable to open mgmt interface for ".
-		  "handler '$handler': $!";
-		return SCST_C_FATAL_ERROR;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	my $bytes;
+	my $errno = $!;
 
-	if ($self->{'debug'}) {
-		print "DBG($$): $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
-	}
+	my $rc = $self->handlerExists($handler);
+	return SCST_C_HND_NO_HANDLER if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_DEV_OPEN_FAIL;
+	$rc = $self->checkDeviceCreateAttributes($handler, $attributes);
+	return SCST_C_DEV_BAD_ATTRIBUTES if ($rc == TRUE);
+	return $rc if ($rc > 1);
+
+	$rc = $self->handlerDeviceExists($handler, $device);
+	return SCST_C_DEV_EXISTS if ($rc == TRUE);
+	return $rc if ($rc > 1);
+
+	return SCST_C_DEV_OPEN_FAIL if ($errno == EINVAL);
+
+	$self->{'err_string'} = "openDevice(): Unable to open mgmt interface for ".
+	    "handler '$handler': $errno";
+	return SCST_C_FATAL_ERROR;
 }
 
 sub closeDevice {
@@ -4375,14 +4184,6 @@ sub closeDevice {
 	return SCST_C_DEV_CLOSE_FAIL if (!defined($handler) ||
 					 !defined($device));
 
-	my $rc = $self->handlerExists($handler);
-	return SCST_C_HND_NO_HANDLER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->handlerDeviceExists($handler, $device);
-	return SCST_C_DEV_NO_DEVICE if ($rc != TRUE);
-	return $rc if ($rc > 1);
-
 	my ($path, $cmd);
 	if (new_sysfs_interface()) {
 		$path = make_path(SCST_ROOT_DIR(), SCST_MGMT_IO);
@@ -4393,23 +4194,30 @@ sub closeDevice {
 	$cmd .= "del_device $device";
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	if (!$io) {
-		$self->{'err_string'} = "closeDevice(): Unable to open mgmt interface for handler ".
-		  "'$handler': $!";
-		return SCST_C_FATAL_ERROR;
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	my $bytes;
+	my $errno = $!;
 
-	if ($self->{'debug'}) {
-		print "DBG($$): $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
-	}
+	my $rc = $self->handlerExists($handler);
+	return SCST_C_HND_NO_HANDLER if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_DEV_CLOSE_FAIL;
+	$rc = $self->handlerDeviceExists($handler, $device);
+	return SCST_C_DEV_NO_DEVICE if ($rc != TRUE);
+	return $rc if ($rc > 1);
+
+	$self->{'err_string'} = "closeDevice(): Unable to open mgmt interface for handler ".
+	    "'$handler': $errno";
+	return SCST_C_FATAL_ERROR;
 }
 
 sub setDeviceAttribute {
@@ -4418,17 +4226,6 @@ sub setDeviceAttribute {
 	my $attribute = shift;
 	my $value = shift;
 
-	my $rc = $self->deviceOpen($device);
-	return SCST_C_DEV_NO_DEVICE if (!$rc);
-	return $rc if ($rc > 1);
-
-	my $attributes = $self->deviceAttributes($device);
-
-	return SCST_C_FATAL_ERROR if (!defined($attributes));
-
-	return SCST_C_DEV_BAD_ATTRIBUTES if (!defined($$attributes{$attribute}));
-	return SCST_C_DEV_ATTRIBUTE_STATIC if ($$attributes{$attribute}->{'static'});
-
 	my ($path, $cmd);
 	if (new_sysfs_interface() &&
 	    ($attribute eq 'filename' ||
@@ -4442,21 +4239,23 @@ sub setDeviceAttribute {
 	$cmd .= $value;
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	return SCST_C_DEV_SETATTR_FAIL if (!$io);
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $cmd > $path\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $cmd > $path\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
 
-	close $io;
+	my $rc = $self->deviceOpen($device);
+	return SCST_C_DEV_NO_DEVICE if (!$rc);
+	return $rc if ($rc > 1);
 
-	return FALSE if ($self->{'debug'} || $bytes);
-	return SCST_C_DEV_SETATTR_FAIL;
+	return setAttrFailed($path, SCST_C_DEV_BAD_ATTRIBUTES,
+			     SCST_C_DEV_ATTRIBUTE_STATIC);
 }
 
 sub checkTargetCreateAttributes {
@@ -4466,13 +4265,14 @@ sub checkTargetCreateAttributes {
 
 	return FALSE if (!defined($check));
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
 	my $available = $self->targetCreateAttributes($driver);
 
-	return SCST_C_FATAL_ERROR if (!defined($available));
+	if (!defined($available)) {
+		my $rc = $self->driverExists($driver);
+		return SCST_C_DRV_NO_DRIVER if (!$rc);
+		return $rc if ($rc > 1);
+		return SCST_C_FATAL_ERROR;
+	}
 
 	if (ref($check) eq 'HASH') {
 		foreach my $attribute (keys %{$check}) {
@@ -4495,12 +4295,6 @@ sub targetCreateAttributes {
 	my $available;
 	my %attributes;
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "targetCreateAttributes(): Driver '$driver' ".
-		  "is not available";
-		return undef;
-	}
-
 	if (new_sysfs_interface()) {
 		my $io = new IO::File make_path(SCST_TARGETS_DIR(), $driver,
 						SCST_ADD_TGT_PARAMS), O_RDONLY;
@@ -4508,13 +4302,19 @@ sub targetCreateAttributes {
 			chomp($attribute);
 			$attributes{$attribute} = '';
 		}
+		close $io;
 	} else {
 		my $io = new IO::File make_path(SCST_TARGETS_DIR(), $driver,
 						SCST_MGMT_IO), O_RDONLY;
 
 		if (!$io) {
-			$self->{'err_string'} = "targetCreateAttributes(): Unable to open driver mgmt ".
-			    "interface for driver '$driver': $!";
+			if ($self->driverExists($driver) != TRUE) {
+				$self->{'err_string'} = "targetCreateAttributes(): Driver '$driver' ".
+				    "is not available";
+			} else {
+				$self->{'err_string'} = "targetCreateAttributes(): Unable to open driver mgmt ".
+				    "interface for driver '$driver': $!";
+			}
 			return undef;
 		}
 
@@ -4524,6 +4324,7 @@ sub targetCreateAttributes {
 				$available =~ s/\.$//;
 			}
 		}
+		close $io;
 
 		if ($available) {
 			foreach my $attribute (split(/\,/, $available)) {
@@ -4583,14 +4384,15 @@ sub deviceGroupDeviceExists {
 	my $group = shift;
 	my $device = shift;
 
-	if ($self->deviceGroupExists($group) != TRUE) {
-		$self->{'err_string'} = "deviceGroupDeviceExists(): Device group '$group' does not exist";
-		return undef;
-	}
-
 	my $devices = $self->deviceGroupDevices($group);
 
-	return SCST_C_FATAL_ERROR if (!defined($devices));
+	if (!defined($devices)) {
+		if ($self->deviceGroupExists($group) != TRUE) {
+			$self->{'err_string'} = "deviceGroupDeviceExists(): Device group '$group' does not exist";
+			return undef;
+		}
+		return SCST_C_FATAL_ERROR;
+	}
 
 	foreach my $_device (@{$devices}) {
 		return TRUE if ($device eq $_device);
@@ -4604,14 +4406,15 @@ sub targetGroupExists {
 	my $group = shift;
 	my $tgroup = shift;
 
-	if ($self->deviceGroupExists($group) != TRUE) {
-		$self->{'err_string'} = "targetGroupExists(): Device group '$group' does not exist";
-		return undef;
-	}
-
 	my $tgroups = $self->targetGroups($group);
 
-	return SCST_C_FATAL_ERROR if (!defined($tgroups));
+	if (!defined($tgroups)) {
+		if ($self->deviceGroupExists($group) != TRUE) {
+			$self->{'err_string'} = "targetGroupExists(): Device group '$group' does not exist";
+			return undef;
+		}
+		return SCST_C_FATAL_ERROR;
+	}
 
 	foreach my $_tgroup (@{$tgroups}) {
 		return TRUE if ($tgroup eq $_tgroup);
@@ -4626,19 +4429,19 @@ sub targetGroupTargetExists {
 	my $tgroup = shift;
 	my $tgt = shift;
 
-	if ($self->deviceGroupExists($group) != TRUE) {
-		$self->{'err_string'} = "targetGroupTargetExists(): Device group '$group' does not exist";
-		return undef;
-	}
-
-	if ($self->targetGroupExists($group, $tgroup) != TRUE) {
-		$self->{'err_string'} = "targetGroupTargetExists(): Target group '$tgroup' does not exist";
-		return undef;
-	}
-
 	my $targets = $self->targetGroupTargets($group, $tgroup);
 
-	return SCST_C_FATAL_ERROR if (!defined($targets));
+	if (!defined($targets)) {
+		if ($self->deviceGroupExists($group) != TRUE) {
+			$self->{'err_string'} = "targetGroupTargetExists(): Device group '$group' does not exist";
+			return undef;
+		} elsif ($self->targetGroupExists($group, $tgroup) != TRUE) {
+			$self->{'err_string'} = "targetGroupTargetExists(): Target group '$tgroup' does not exist";
+			return undef;
+		} else {
+			return SCST_C_FATAL_ERROR;
+		}
+	}
 
 	foreach my $_tgt (@{$targets}) {
 		return TRUE if ($tgt eq $_tgt);
@@ -4656,23 +4459,25 @@ sub checkLunCreateAttributes {
 
 	return FALSE if (!defined($check));
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	if ($group) {
-		$rc = $self->groupExists($driver, $target, $group);
-		return SCST_C_GRP_NO_GROUP if (!$rc);
-		return $rc if ($rc > 1);
-	}
-
 	my $available = $self->lunCreateAttributes($driver, $target, $group);
 
-	return SCST_C_FATAL_ERROR if (!defined($available));
+	if (!defined($available)) {
+		my $rc = $self->driverExists($driver);
+		return SCST_C_DRV_NO_DRIVER if (!$rc);
+		return $rc if ($rc > 1);
+
+		$rc = $self->targetExists($driver, $target);
+		return SCST_C_TGT_NO_TARGET if (!$rc);
+		return $rc if ($rc > 1);
+
+		if ($group) {
+			$rc = $self->groupExists($driver, $target, $group);
+			return SCST_C_GRP_NO_GROUP if (!$rc);
+			return $rc if ($rc > 1);
+		}
+
+		return SCST_C_FATAL_ERROR;
+	}
 
 	if (ref($check) eq 'HASH') {
 		foreach my $attribute (keys %{$check}) {
@@ -4697,18 +4502,6 @@ sub lunCreateAttributes {
 	my $available;
 	my %attributes;
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "lunCreateAttributes(): Driver '$driver' ".
-		  "is not available";
-		return undef;
-	}
-
-	if ($self->targetExists($driver, $target) != TRUE) {
-		$self->{'err_string'} = "lunCreateAttributes(): Target '$target' ".
-		  "is not available";
-		return undef;
-	}
-
 	my $_path;
 
 	if (new_sysfs_interface()) {
@@ -4732,14 +4525,9 @@ sub lunCreateAttributes {
 			chomp($attribute);
 			$attributes{$attribute} = '';
 		}
+		close $io;
 	} else {
 		if (defined($group)) {
-			if ($self->groupExists($driver, $target, $group) != TRUE) {
-				$self->{'err_string'} = "lunCreateAttributes(): Group '$group' ".
-				    "does not exist";
-				return undef;
-			}
-
 			$_path = make_path(SCST_TARGETS_DIR(), $driver, $target,
 					   SCST_GROUPS, $group, SCST_LUNS,
 					   SCST_MGMT_IO);
@@ -4751,8 +4539,19 @@ sub lunCreateAttributes {
 		my $io = new IO::File $_path, O_RDONLY;
 
 		if (!$io) {
-			$self->{'err_string'} = "lunCreateAttributes(): Unable to open luns mgmt ".
-			    "interface for group '$group': $!";
+			if ($self->driverExists($driver) != TRUE) {
+				$self->{'err_string'} = "lunCreateAttributes(): Driver '$driver' ".
+				    "is not available";
+			} elsif ($self->targetExists($driver, $target) != TRUE) {
+				$self->{'err_string'} = "lunCreateAttributes(): Target '$target' ".
+				    "is not available";
+			} elsif (defined($group) && $self->groupExists($driver, $target, $group) != TRUE) {
+				$self->{'err_string'} = "lunCreateAttributes(): Group '$group' ".
+				    "does not exist";
+			} else {
+				$self->{'err_string'} = "lunCreateAttributes(): Unable to open luns mgmt ".
+				    "interface for group '$group': $!";
+			}
 			return undef;
 		}
 
@@ -4762,6 +4561,7 @@ sub lunCreateAttributes {
 				$available =~ s/\.$//;
 			}
 		}
+		close $io;
 
 		if ($available) {
 			foreach my $attribute (split(/\,/, $available)) {
@@ -4783,21 +4583,23 @@ sub checkInitiatorCreateAttributes {
 
 	return FALSE if (!defined($check));
 
-	my $rc = $self->driverExists($driver);
-	return SCST_C_DRV_NO_DRIVER if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->targetExists($driver, $target);
-	return SCST_C_TGT_NO_TARGET if (!$rc);
-	return $rc if ($rc > 1);
-
-	$rc = $self->groupExists($driver, $target, $group);
-	return SCST_C_GRP_NO_GROUP if (!$rc);
-	return $rc if ($rc > 1);
-
 	my $available = $self->initiatorCreateAttributes($driver, $target, $group);
 
-	return SCST_C_FATAL_ERROR if (!defined($available));
+	if (!defined($available)) {
+		my $rc = $self->driverExists($driver);
+		return SCST_C_DRV_NO_DRIVER if (!$rc);
+		return $rc if ($rc > 1);
+
+		$rc = $self->targetExists($driver, $target);
+		return SCST_C_TGT_NO_TARGET if (!$rc);
+		return $rc if ($rc > 1);
+
+		$rc = $self->groupExists($driver, $target, $group);
+		return SCST_C_GRP_NO_GROUP if (!$rc);
+		return $rc if ($rc > 1);
+
+		return SCST_C_FATAL_ERROR;
+	}
 
 	if (ref($check) eq 'HASH') {
 		foreach my $attribute (keys %{$check}) {
@@ -4822,24 +4624,6 @@ sub initiatorCreateAttributes {
 	my $available;
 	my %attributes;
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "initiatorCreateAttributes(): Driver '$driver' ".
-		  "is not available";
-		return undef;
-	}
-
-	if ($self->targetExists($driver, $target) != TRUE) {
-		$self->{'err_string'} = "initiatorCreateAttributes(): Target '$target' ".
-		  "is not available";
-		return undef;
-	}
-
-	if ($self->groupExists($driver, $target, $group) != TRUE) {
-		$self->{'err_string'} = "initiatorCreateAttributes(): Group '$group' ".
-		  "does not exist";
-		return undef;
-	}
-
 	if (new_sysfs_interface()) {
 		# Do nothing - there are no initiator attributes (yet).
 	} else {
@@ -4849,8 +4633,20 @@ sub initiatorCreateAttributes {
 				O_RDONLY;
 
 		if (!$io) {
-			$self->{'err_string'} = "initiatorCreateAttributes(): Unable to open initiators mgmt ".
-			    "interface for group '$group': $!";
+			if ($self->driverExists($driver) != TRUE) {
+				$self->{'err_string'} = "initiatorCreateAttributes(): Driver '$driver' ".
+				    "is not available";
+			} elsif ($self->targetExists($driver, $target) != TRUE) {
+				$self->{'err_string'} = "initiatorCreateAttributes(): Target '$target' ".
+				    "is not available";
+				return undef;
+			} elsif ($self->groupExists($driver, $target, $group) != TRUE) {
+				$self->{'err_string'} = "initiatorCreateAttributes(): Group '$group' ".
+				    "does not exist";
+			} else {
+				$self->{'err_string'} = "initiatorCreateAttributes(): Unable to open initiators mgmt ".
+				    "interface for group '$group': $!";
+			}
 			return undef;
 		}
 
@@ -4860,6 +4656,7 @@ sub initiatorCreateAttributes {
 				$available =~ s/\.$//;
 			}
 		}
+		close $io;
 
 		if ($available) {
 			foreach my $attribute (split(/\,/, $available)) {
@@ -4881,23 +4678,19 @@ sub sessions {
 
 	return undef if (!defined($driver) || !defined($target));
 
-	if ($self->driverExists($driver) != TRUE) {
-		$self->{'err_string'} = "sessions(): Driver '$driver' ".
-		  "is not available";
-		return undef;
-	}
-
-	if ($self->targetExists($driver, $target) != TRUE) {
-		$self->{'err_string'} = "sessions(): Target '$target' ".
-		  "is not available";
-		return undef;
-	}
-
 	my $sHandle = new IO::Handle;
 	my $_path = make_path(SCST_TARGETS_DIR(), $driver, $target,
 			      SCST_SESSIONS);
 	if (!(opendir $sHandle, $_path)) {
-		$self->{'err_string'} = "sessions(): Unable to read directory '$_path': $!";
+		if ($self->driverExists($driver) != TRUE) {
+			$self->{'err_string'} = "sessions(): Driver '$driver' ".
+			    "is not available";
+		} elsif ($self->targetExists($driver, $target) != TRUE) {
+			$self->{'err_string'} = "sessions(): Target '$target' ".
+			    "is not available";
+		} else {
+			$self->{'err_string'} = "sessions(): Unable to read directory '$_path': $!";
+		}
 		return undef;
 	}
 
@@ -4949,6 +4742,7 @@ sub sessions {
 						}
 
 						my $value = <$io>;
+						close $io;
 						chomp $value;
 
 						$_sessions{$session}->{$attribute}->{'value'} = $value;
@@ -4957,7 +4751,9 @@ sub sessions {
 				}
 			}
 		}
+		close $pHandle;
 	}
+	close $sHandle;
 
 	return \%_sessions;
 }
@@ -4979,18 +4775,17 @@ sub closeSession {
 			     SCST_SESSIONS, $session, 'force_close');
 
 	my $io = new IO::File $path, O_WRONLY;
-
-	my $cmd = "1";
-
-	my $bytes;
-
-	if ($self->{'debug'}) {
-		print "DBG($$): $cmd\n";
-	} else {
-		$bytes = _syswrite($io, $cmd, length($cmd));
+	if ($io) {
+		my $cmd = "1";
+		my $bytes;
+		if ($self->{'debug'}) {
+			print "DBG($$): $cmd\n";
+		} else {
+			$bytes = _syswrite($io, $cmd, length($cmd));
+		}
+		close $io;
+		return FALSE if ($self->{'debug'} || $bytes);
 	}
-
-	return FALSE if ($self->{'debug'} || $bytes);
 	return SCST_C_SESSION_CLOSE_FAIL;
 }
 
@@ -5032,9 +4827,11 @@ sub sgvStats {
 				while (my $value = <$io>) {
 					$buffer .= $value;
 				}
+				close $io;
 
 				$stats{$stat}->{$lief} = $buffer;
 			}
+			close $lHandle;
 		} else {
 			my $io = new IO::File $sPath, O_RDONLY;
 
@@ -5048,10 +4845,12 @@ sub sgvStats {
 			while (my $value = <$io>) {
 				$buffer .= $value;
 			}
+			close $io;
 
 			$stats{$stat} = $buffer;
 		}
 	}
+	close $sHandle;
 
 	return \%stats;
 }