Generic support for --consistency-policy and PPL

Add a new parameter to mdadm: --consistency-policy=. It determines how
the array maintains consistency in case of unexpected shutdown. This
maps to the md sysfs attribute 'consistency_policy'. It can be used to
create a raid5 array using PPL. Add the necessary plumbing to pass this
option to metadata handlers. The write journal and bitmap
functionalities are treated as different policies, which are implicitly
selected when using --write-journal or --bitmap options.

Signed-off-by: Artur Paszkiewicz <artur.paszkiewicz@intel.com>
Signed-off-by: Jes Sorensen <Jes.Sorensen@gmail.com>

1 files changed, 52 insertions, 3 deletions

diff --git a/mdadm.c b/mdadm.c
index 08ddcab..d4e8286 100644
--- a/mdadm.c
+++ b/mdadm.c
@@ -78,6 +78,7 @@ int main(int argc, char *argv[])
 		.level		= UnSet,
 		.layout		= UnSet,
 		.bitmap_chunk	= UnSet,
+		.consistency_policy	= UnSet,
 	};
 
 	char sys_hostname[256];
@@ -1215,6 +1216,16 @@ int main(int argc, char *argv[])
 
 			s.journaldisks = 1;
 			continue;
+		case O(CREATE, 'k'):
+			s.consistency_policy = map_name(consistency_policies,
+							optarg);
+			if (s.consistency_policy == UnSet ||
+			    s.consistency_policy < CONSISTENCY_POLICY_RESYNC) {
+				pr_err("Invalid consistency policy: %s\n",
+				       optarg);
+				exit(2);
+			}
+			continue;
 		}
 		/* We have now processed all the valid options. Anything else is
 		 * an error
@@ -1242,9 +1253,47 @@ int main(int argc, char *argv[])
 		exit(0);
 	}
 
-	if (s.journaldisks && (s.level < 4 || s.level > 6)) {
-		pr_err("--write-journal is only supported for RAID level 4/5/6.\n");
-		exit(2);
+	if (s.journaldisks) {
+		if (s.level < 4 || s.level > 6) {
+			pr_err("--write-journal is only supported for RAID level 4/5/6.\n");
+			exit(2);
+		}
+		if (s.consistency_policy != UnSet &&
+		    s.consistency_policy != CONSISTENCY_POLICY_JOURNAL) {
+			pr_err("--write-journal is not supported with consistency policy: %s\n",
+			       map_num(consistency_policies, s.consistency_policy));
+			exit(2);
+		}
+	}
+
+	if (mode == CREATE && s.consistency_policy != UnSet) {
+		if (s.level <= 0) {
+			pr_err("--consistency-policy not meaningful with level %s.\n",
+			       map_num(pers, s.level));
+			exit(2);
+		} else if (s.consistency_policy == CONSISTENCY_POLICY_JOURNAL &&
+			   !s.journaldisks) {
+			pr_err("--write-journal is required for consistency policy: %s\n",
+			       map_num(consistency_policies, s.consistency_policy));
+			exit(2);
+		} else if (s.consistency_policy == CONSISTENCY_POLICY_PPL &&
+			   s.level != 5) {
+			pr_err("PPL consistency policy is only supported for RAID level 5.\n");
+			exit(2);
+		} else if (s.consistency_policy == CONSISTENCY_POLICY_BITMAP &&
+			   (!s.bitmap_file ||
+			    strcmp(s.bitmap_file, "none") == 0)) {
+			pr_err("--bitmap is required for consistency policy: %s\n",
+			       map_num(consistency_policies, s.consistency_policy));
+			exit(2);
+		} else if (s.bitmap_file &&
+			   strcmp(s.bitmap_file, "none") != 0 &&
+			   s.consistency_policy != CONSISTENCY_POLICY_BITMAP &&
+			   s.consistency_policy != CONSISTENCY_POLICY_JOURNAL) {
+			pr_err("--bitmap is not compatible with consistency policy: %s\n",
+			       map_num(consistency_policies, s.consistency_policy));
+			exit(2);
+		}
 	}
 
 	if (!mode && devs_found) {