Remove NON_BLOCKING lock flag from tools and set a policy to auto-set.

As a simplification to the tools and further liblvm, this patch pushes
the setting of NON_BLOCKING lock flag inside the lock_vol() call.
The policy we set is if any existing VGs are currently locked, we
set the NON_BLOCKING flag.

Should be no functional change.

WHATS_NEW

@@ -1,5 +1,6 @@
 Version 2.02.46 - 
 ================================
+  Remove NON_BLOCKING lock flag from tools and set a policy to auto-set.
   Remove snapshot_count from VG and use function instead.
   Fix first_seg() call for empty segment list.
   Add make install_lvm2 as complement to device-mapper install.

lib/locking/locking.c

@@ -376,6 +376,14 @@ int lock_vol(struct cmd_context *cmd, const char *vol, uint32_t flags)
 
 	switch (flags & LCK_SCOPE_MASK) {
 	case LCK_VG:
+		/*
+		 * Automatically set LCK_NONBLOCK if one or more VGs locked.
+		 * This will enforce correctness and prevent deadlocks rather
+		 * than relying on the caller to set the flag properly.
+		 */
+		if (vgs_locked())
+			flags |= LCK_NONBLOCK;
+
 		/* Lock VG to change on-disk metadata. */
 		/* If LVM1 driver knows about the VG, it can't be accessed. */
 		if (!check_lvm1_vg_inactive(cmd, vol))

tools/vgcfgrestore.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
  *
  * This file is part of LVM2.
  *
@@ -48,7 +48,7 @@ int vgcfgrestore(struct cmd_context *cmd, int argc, char **argv)
 		return ECMD_FAILED;
 	}
 
-	if (!lock_vol(cmd, vg_name, LCK_VG_WRITE | LCK_NONBLOCK)) {
+	if (!lock_vol(cmd, vg_name, LCK_VG_WRITE)) {
 		log_error("Unable to lock volume group %s", vg_name);
 		unlock_vg(cmd, VG_ORPHANS);
 		return ECMD_FAILED;

tools/vgcreate.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
  *
  * This file is part of LVM2.
  *
@@ -51,7 +51,7 @@ int vgcreate(struct cmd_context *cmd, int argc, char **argv)
 		return ECMD_FAILED;
 	}
 
-	if (!lock_vol(cmd, vp_new.vg_name, LCK_VG_WRITE | LCK_NONBLOCK)) {
+	if (!lock_vol(cmd, vp_new.vg_name, LCK_VG_WRITE)) {
 		log_error("Can't get lock for %s", vp_new.vg_name);
 		unlock_vg(cmd, VG_ORPHANS);
 		return ECMD_FAILED;

tools/vgextend.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
  *
  * This file is part of LVM2.
  *
@@ -42,7 +42,7 @@ int vgextend(struct cmd_context *cmd, int argc, char **argv)
 	}
 
 	log_verbose("Checking for volume group \"%s\"", vg_name);
-	if (!(vg = vg_lock_and_read(cmd, vg_name, NULL, LCK_VG_WRITE | LCK_NONBLOCK,
+	if (!(vg = vg_lock_and_read(cmd, vg_name, NULL, LCK_VG_WRITE,
 				    CLUSTERED | EXPORTED_VG |
 				    LVM_WRITE | RESIZEABLE_VG,
 				    CORRECT_INCONSISTENT | FAIL_INCONSISTENT))) {

tools/vgmerge.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
  *
  * This file is part of LVM2.
  *
@@ -35,7 +35,7 @@ static int _vgmerge_single(struct cmd_context *cmd, const char *vg_name_to,
 
 	log_verbose("Checking for volume group \"%s\"", vg_name_from);
 	if (!(vg_from = vg_lock_and_read(cmd, vg_name_from, NULL,
-					 LCK_VG_WRITE | LCK_NONBLOCK,
+					 LCK_VG_WRITE,
 					 CLUSTERED | EXPORTED_VG | LVM_WRITE,
 					 CORRECT_INCONSISTENT | FAIL_INCONSISTENT))) {
 		unlock_release_vg(cmd, vg_to, vg_name_to);

tools/vgreduce.c

@@ -397,7 +397,7 @@ static int _vgreduce_single(struct cmd_context *cmd, struct volume_group *vg,
 		return ECMD_FAILED;
 	}
 
-	if (!lock_vol(cmd, VG_ORPHANS, LCK_VG_WRITE | LCK_NONBLOCK)) {
+	if (!lock_vol(cmd, VG_ORPHANS, LCK_VG_WRITE)) {
 		log_error("Can't get lock for orphan PVs");
 		return ECMD_FAILED;
 	}

tools/vgremove.c

@@ -1,6 +1,6 @@
 /*
  * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
- * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2004-2009 Red Hat, Inc. All rights reserved.
  *
  * This file is part of LVM2.
  *
@@ -41,7 +41,7 @@ int vgremove(struct cmd_context *cmd, int argc, char **argv)
 	}
 
 	ret = process_each_vg(cmd, argc, argv,
-			      LCK_VG_WRITE | LCK_NONBLOCK, 1,
+			      LCK_VG_WRITE, 1,
 			      NULL, &vgremove_single);
 
 	unlock_vg(cmd, VG_ORPHANS);

tools/vgrename.c

@@ -100,7 +100,7 @@ static int vg_rename_path(struct cmd_context *cmd, const char *old_vg_path,
 
 	log_verbose("Checking for new volume group \"%s\"", vg_name_new);
 
-	if (!lock_vol(cmd, vg_name_new, LCK_VG_WRITE | LCK_NONBLOCK)) {
+	if (!lock_vol(cmd, vg_name_new, LCK_VG_WRITE)) {
 		unlock_release_vg(cmd, vg, vg_name_old);
 		log_error("Can't get lock for %s", vg_name_new);
 		return 0;

tools/vgsplit.c

@@ -325,7 +325,7 @@ int vgsplit(struct cmd_context *cmd, int argc, char **argv)
 		 return ECMD_FAILED;
 
 	log_verbose("Checking for new volume group \"%s\"", vg_name_to);
-	if (!lock_vol(cmd, vg_name_to, LCK_VG_WRITE | LCK_NONBLOCK)) {
+	if (!lock_vol(cmd, vg_name_to, LCK_VG_WRITE)) {
 		log_error("Can't get lock for %s", vg_name_to);
 		unlock_release_vg(cmd, vg_from, vg_name_from);
 		return ECMD_FAILED;