mdadm: load default sysfs attributes after assemblation

Added new type of line to mdadm.conf which allows to specify values of
sysfs attributes for MD devices that should be loaded after the array is
assembled. Each line is interpreted as list of structures containing
sysname of MD device (md126 etc.) and list of sysfs attributes and their
values.

Signed-off-by: Mariusz Dabrowski <mariusz.dabrowski@intel.com>
Signed-off-by: Krzysztof Smolinski <krzysztof.smolinski@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>

Assemble.c

@@ -1063,9 +1063,12 @@ static int start_array(int mdfd,
 			       mddev, okcnt + sparecnt + journalcnt,
 			       okcnt + sparecnt + journalcnt == 1 ? "" : "s");
 			if (okcnt < (unsigned)content->array.raid_disks)
-				fprintf(stderr, " (out of %d)",
+				fprintf(stderr, " (out of %d)\n",
 					content->array.raid_disks);
-			fprintf(stderr, "\n");
+			else {
+				fprintf(stderr, "\n");
+				sysfs_rules_apply(mddev, content);
+			}
 		}
 
 		if (st->ss->validate_container) {
@@ -1139,6 +1142,7 @@ static int start_array(int mdfd,
 			rv = ioctl(mdfd, RUN_ARRAY, NULL);
 		reopen_mddev(mdfd); /* drop O_EXCL */
 		if (rv == 0) {
+			sysfs_rules_apply(mddev, content);
 			if (c->verbose >= 0) {
 				pr_err("%s has been started with %d drive%s",
 				       mddev, okcnt, okcnt==1?"":"s");
@@ -2130,10 +2134,12 @@ int assemble_container_content(struct supertype *st, int mdfd,
 			pr_err("array %s now has %d device%s",
 			       chosen_name, working + preexist,
 			       working + preexist == 1 ? "":"s");
-		else
+		else {
+			sysfs_rules_apply(chosen_name, content);
 			pr_err("Started %s with %d device%s",
 			       chosen_name, working + preexist,
 			       working + preexist == 1 ? "":"s");
+		}
 		if (preexist)
 			fprintf(stderr, " (%d new)", working);
 		if (expansion)

Incremental.c

@@ -480,6 +480,7 @@ int Incremental(struct mddev_dev *devlist, struct context *c,
 			pr_err("container %s now has %d device%s\n",
 			       chosen_name, info.array.working_disks,
 			       info.array.working_disks == 1?"":"s");
+		sysfs_rules_apply(chosen_name, &info);
 		wait_for(chosen_name, mdfd);
 		if (st->ss->external)
 			strcpy(devnm, fd2devnm(mdfd));

config.c

@@ -80,7 +80,8 @@ char DefaultAltConfFile[] = CONFFILE2;
 char DefaultAltConfDir[] = CONFFILE2 ".d";
 
 enum linetype { Devices, Array, Mailaddr, Mailfrom, Program, CreateDev,
-		Homehost, HomeCluster, AutoMode, Policy, PartPolicy, LTEnd };
+		Homehost, HomeCluster, AutoMode, Policy, PartPolicy, Sysfs,
+		LTEnd };
 char *keywords[] = {
 	[Devices]  = "devices",
 	[Array]    = "array",
@@ -93,6 +94,7 @@ char *keywords[] = {
 	[AutoMode] = "auto",
 	[Policy]   = "policy",
 	[PartPolicy]="part-policy",
+	[Sysfs]    = "sysfs",
 	[LTEnd]    = NULL
 };
 
@@ -764,6 +766,9 @@ void conf_file(FILE *f)
 		case PartPolicy:
 			policyline(line, rule_part);
 			break;
+		case Sysfs:
+			sysfsline(line);
+			break;
 		default:
 			pr_err("Unknown keyword %s\n", line);
 		}

mdadm.conf.5

@@ -587,6 +587,26 @@ be based on the domain, but with
 appended, when N is the partition number for the partition that was
 found.
 
+.TP
+.B SYSFS
+The SYSFS line lists custom values of MD device's sysfs attributes which will be
+stored in sysfs after the array is assembled. Multiple lines are allowed and each
+line has to contain the uuid or the name of the device to which it relates.
+.RS 4
+.TP
+.B uuid=
+hexadecimal identifier of MD device. This has to match the uuid stored in the
+superblock.
+.TP
+.B name=
+name of the MD device as was given to
+.I mdadm
+when the array was created. It will be ignored if
+.B uuid
+is not empty.
+.TP
+.RS 7
+
 .SH EXAMPLE
 DEVICE /dev/sd[bcdjkl]1
 .br
@@ -657,6 +677,11 @@ CREATE group=system mode=0640 auto=part\-8
 HOMEHOST <system>
 .br
 AUTO +1.x homehost \-all
+.br
+SYSFS name=/dev/md/raid5 group_thread_cnt=4 sync_speed_max=1000000
+.br
+SYSFS uuid=bead5eb6:31c17a27:da120ba2:7dfda40d group_thread_cnt=4
+sync_speed_max=1000000
 
 .SH SEE ALSO
 .BR mdadm (8),

mdadm.h

@@ -1322,6 +1322,9 @@ void domain_add(struct domainlist **domp, char *domain);
 extern void policy_save_path(char *id_path, struct map_ent *array);
 extern int policy_check_path(struct mdinfo *disk, struct map_ent *array);
 
+extern void sysfs_rules_apply(char *devnm, struct mdinfo *dev);
+extern void sysfsline(char *line);
+
 #if __GNUC__ < 3
 struct stat64;
 #endif

sysfs.c

@@ -26,9 +26,22 @@
 #include	"mdadm.h"
 #include	<dirent.h>
 #include	<ctype.h>
+#include	"dlink.h"
 
 #define MAX_SYSFS_PATH_LEN	120
 
+struct dev_sysfs_rule {
+	struct dev_sysfs_rule *next;
+	char *devname;
+	int uuid[4];
+	int uuid_set;
+	struct sysfs_entry {
+		struct sysfs_entry *next;
+		char *name;
+		char *value;
+	} *entry;
+};
+
 int load_sys(char *path, char *buf, int len)
 {
 	int fd = open(path, O_RDONLY);
@@ -999,3 +1012,148 @@ int sysfs_wait(int fd, int *msec)
 	}
 	return n;
 }
+
+int sysfs_rules_apply_check(const struct mdinfo *sra,
+			    const struct sysfs_entry *ent)
+{
+	/* Check whether parameter is regular file,
+	 * exists and is under specified directory.
+	 */
+	char fname[MAX_SYSFS_PATH_LEN];
+	char dname[MAX_SYSFS_PATH_LEN];
+	char resolved_path[PATH_MAX];
+	char resolved_dir[PATH_MAX];
+
+	if (sra == NULL || ent == NULL)
+		return -1;
+
+	snprintf(dname, MAX_SYSFS_PATH_LEN, "/sys/block/%s/md/", sra->sys_name);
+	snprintf(fname, MAX_SYSFS_PATH_LEN, "%s/%s", dname, ent->name);
+
+	if (realpath(fname, resolved_path) == NULL ||
+	    realpath(dname, resolved_dir) == NULL)
+		return -1;
+
+	if (strncmp(resolved_dir, resolved_path,
+		    strnlen(resolved_dir, PATH_MAX)) != 0)
+		return -1;
+
+	return 0;
+}
+
+static struct dev_sysfs_rule *sysfs_rules;
+
+void sysfs_rules_apply(char *devnm, struct mdinfo *dev)
+{
+	struct dev_sysfs_rule *rules = sysfs_rules;
+
+	while (rules) {
+		struct sysfs_entry *ent = rules->entry;
+		int match  = 0;
+
+		if (!rules->uuid_set) {
+			if (rules->devname)
+				match = strcmp(devnm, rules->devname) == 0;
+		} else {
+			match = memcmp(dev->uuid, rules->uuid,
+				       sizeof(int[4])) == 0;
+		}
+
+		while (match && ent) {
+			if (sysfs_rules_apply_check(dev, ent) < 0)
+				pr_err("SYSFS: failed to write '%s' to '%s'\n",
+					ent->value, ent->name);
+			else
+				sysfs_set_str(dev, NULL, ent->name, ent->value);
+			ent = ent->next;
+		}
+		rules = rules->next;
+	}
+}
+
+static void sysfs_rule_free(struct dev_sysfs_rule *rule)
+{
+	struct sysfs_entry *entry;
+
+	while (rule) {
+		struct dev_sysfs_rule *tmp = rule->next;
+
+		entry = rule->entry;
+		while (entry) {
+			struct sysfs_entry *tmp = entry->next;
+
+			free(entry->name);
+			free(entry->value);
+			free(entry);
+			entry = tmp;
+		}
+
+		if (rule->devname)
+			free(rule->devname);
+		free(rule);
+		rule = tmp;
+	}
+}
+
+void sysfsline(char *line)
+{
+	struct dev_sysfs_rule *sr;
+	char *w;
+
+	sr = xcalloc(1, sizeof(*sr));
+	for (w = dl_next(line); w != line ; w = dl_next(w)) {
+		if (strncasecmp(w, "name=", 5) == 0) {
+			char *devname = w + 5;
+
+			if (strncmp(devname, "/dev/md/", 8) == 0) {
+				if (sr->devname)
+					pr_err("Only give one device per SYSFS line: %s\n",
+						devname);
+				else
+					sr->devname = xstrdup(devname);
+			} else {
+				pr_err("%s is an invalid name for an md device - ignored.\n",
+				       devname);
+			}
+		} else if (strncasecmp(w, "uuid=", 5) == 0) {
+			char *uuid = w + 5;
+
+			if (sr->uuid_set) {
+				pr_err("Only give one uuid per SYSFS line: %s\n",
+					uuid);
+			} else {
+				if (parse_uuid(w + 5, sr->uuid) &&
+				    memcmp(sr->uuid, uuid_zero,
+					   sizeof(int[4])) != 0)
+					sr->uuid_set = 1;
+				else
+					pr_err("Invalid uuid: %s\n", uuid);
+			}
+		} else {
+			struct sysfs_entry *prop;
+
+			char *sep = strchr(w, '=');
+
+			if (sep == NULL || *(sep + 1) == 0) {
+				pr_err("Cannot parse \"%s\" - ignoring.\n", w);
+				continue;
+			}
+
+			prop = xmalloc(sizeof(*prop));
+			prop->value = xstrdup(sep + 1);
+			*sep = 0;
+			prop->name = xstrdup(w);
+			prop->next = sr->entry;
+			sr->entry = prop;
+		}
+	}
+
+	if (!sr->devname && !sr->uuid_set) {
+		pr_err("Device name not found in sysfs config entry - ignoring.\n");
+		sysfs_rule_free(sr);
+		return;
+	}
+
+	sr->next = sysfs_rules;
+	sysfs_rules = sr;
+}