bcacheadm: add command to modify sysfs attributes for

a cache or cacheset

bcacheadm modify -u csetuuid -d cacheuuid attr val
bcacheadm modify -u csetuuid attr val
bcacheadm modify --list

Change-Id: I7b8ddfb6a7cd12a7bc71870dcc10787a7d3d9e8d
Signed-off-by: Jacob Malevich <jam@daterainc.com>

bcache.c

@@ -868,6 +868,40 @@ void show_super_cache(struct cache_sb *sb, bool force_csum)
 	show_cache_member(sb, sb->nr_this_dev);
 }
 
+static int __sysfs_attr_type(char *attr, const char **attr_arr) {
+	int i, j;
+	for(i = 0; attr_arr[i] != NULL; i++)
+		if(!strcmp(attr, attr_arr[i]))
+			return 1;
+	return 0;
+}
+
+enum sysfs_attr sysfs_attr_type(char *attr) {
+	int ret;
+	if(__sysfs_attr_type(attr, set_attrs))
+		return SET_ATTR;
+	if(__sysfs_attr_type(attr, cache_attrs))
+		return CACHE_ATTR;
+	if(__sysfs_attr_type(attr, internal_attrs))
+		return INTERNAL_ATTR;
+
+	printf("No attribute called %s, try --list to see options\n", attr);
+
+	return -1;
+}
+
+static void __sysfs_attr_list(const char **attr_arr) {
+	int i, j;
+	for (i = 0; attr_arr[i] != NULL; i++)
+		printf("%s\n", attr_arr[i]);
+}
+
+void sysfs_attr_list() {
+	__sysfs_attr_list(set_attrs);
+	__sysfs_attr_list(cache_attrs);
+	__sysfs_attr_list(internal_attrs);
+}
+
 struct cache_sb *query_dev(char *dev, bool force_csum,
 		bool print_sb, bool uuid_only, char *dev_uuid)
 {
@@ -879,7 +913,6 @@ struct cache_sb *query_dev(char *dev, bool force_csum,
 		printf("Can't open dev %s: %s\n", dev, strerror(errno));
 		exit(2);
 	}
-	printf("opened sb for %s\n", dev);
 
 	if (pread(fd, sb, bytes, SB_START) != bytes) {
 		fprintf(stderr, "Couldn't read\n");

bcache.h

@@ -30,12 +30,6 @@ typedef __s64	s64;
 	(void) (&_max1 == &_max2);		\
 	_max1 > _max2 ? _max1 : _max2; })
 
-struct add_msg {
-	char *const *devs;
-	char *uuid;
-	int tier;
-};
-
 extern const char * const cache_state[];
 extern const char * const replacement_policies[];
 extern const char * const csum_types[];
@@ -63,6 +57,47 @@ long strtoul_or_die(const char *, size_t, const char *);
 void show_super_backingdev(struct cache_sb *, bool);
 void show_super_cache(struct cache_sb *, bool);
 
+enum sysfs_attr {SET_ATTR, CACHE_ATTR, INTERNAL_ATTR};
+
+static const char *set_attrs[] = {
+	"btree_flush_delay",
+	"btree_scan_ratelimit",
+	"bucket_reserve_percent",
+	"cache_reserve_percent",
+	"checksum_type",
+	"congested_read_threshold_us",
+	"congested_write_threshold_us",
+	"data_replicas",
+	"errors",
+	"foreground_target_percent",
+	"gc_sector_percent",
+	"journal_delay_ms",
+	"meta_replicas",
+	"sector_reserve_percent",
+	"tiering_percent",
+	NULL
+};
+
+static const char *cache_attrs[] = {
+	"cache_replacement_policy",
+	"discard",
+	"state",
+	"tier",
+	NULL
+};
+
+static const char *internal_attrs[] = {
+	"btree_shrinker_disabled",
+	"copy_gc_enabled",
+	"foreground_write_rate",
+	"tiering_enabled",
+	"tiering_rate",
+	NULL
+};
+
+enum sysfs_attr sysfs_attr_type(char *attr);
+void sysfs_attr_list();
+
 struct cache_sb *query_dev(char *, bool, bool, bool, char *dev_uuid);
 char *list_cachesets(char *, bool);
 char *parse_array_to_list(char *const *);

bcacheadm.c

@@ -37,16 +37,6 @@
 #define MAX_DEVS MAX_CACHES_PER_SET
 
 
-/* bcacheadm globals */
-enum exit {
-	EXIT_OK = 0,		/* Ok */
-	EXIT_ERROR = 1,		/* General/OS error */
-	EXIT_SHELL = 2,		/* Start maintenance shell */
-	EXIT_SHELL_REBOOT = 3,	/* Start maintenance shell, reboot when done */
-	EXIT_REBOOT = 4,	/* System must reboot */
-};
-
-
 /* make-bcache globals */
 int bdev = -1;
 int devs = 0;
@@ -63,13 +53,6 @@ unsigned replication_set = 0, replacement_policy = 0;
 uint64_t data_offset = BDEV_DATA_START_DEFAULT;
 char *label = NULL;
 struct cache_sb *cache_set_sb = NULL;
-enum long_opts {
-	CACHE_SET_UUID = 256,
-	CSUM_TYPE,
-	REPLICATION_SET,
-	META_REPLICAS,
-	DATA_REPLICAS,
-};
 const char *cache_set_uuid = 0;
 const char *csum_type = 0;
 char *metadata_replicas = 0;
@@ -82,6 +65,11 @@ char *add_dev_uuid = NULL;
 /* rm-dev globals */
 bool force_remove = false;
 
+/* Modify globals */
+bool modify_list_attrs = false;
+static const char *modify_set_uuid = NULL;
+static const char *modify_dev_uuid = NULL;
+
 /* query-dev globals */
 bool force_csum = false;
 bool uuid_only = false;
@@ -218,6 +206,13 @@ static NihOption bcache_rm_device_options[] = {
 	NIH_OPTION_LAST
 };
 
+static NihOption bcache_modify_options[] = {
+	{'l', "list", N_("list attributes"), NULL, NULL, &modify_list_attrs, NULL},
+	{'u', "set", N_("cacheset uuid"), NULL, "UUID", &modify_set_uuid, NULL},
+	{'d', "dev", N_("device uuid"), NULL, "UUID", &modify_dev_uuid, NULL},
+	NIH_OPTION_LAST
+};
+
 static NihOption query_devs_options[] = {
 	{'f', "force_csum", N_("force_csum"), NULL, NULL, &force_csum, NULL},
 	{'u', "uuid-only", N_("only print out the uuid for the devices, not the whole superblock"), NULL, NULL, &uuid_only, NULL},
@@ -403,8 +398,10 @@ int bcache_add_devices(NihCommand *command, char *const *args)
 {
 	char *err;
 
-	if (!add_dev_uuid)
+	if (!add_dev_uuid) {
 		printf("Must specify a cacheset uuid to add the disk to\n");
+		return -1;
+	}
 
 	err = add_devices(args, add_dev_uuid);
 	if (err) {
@@ -428,6 +425,82 @@ int bcache_rm_device(NihCommand *command, char *const *args)
 	return 0;
 }
 
+int bcache_modify(NihCommand *command, char *const *args)
+{
+	char *err;
+	char path[MAX_PATH];
+	DIR *path_dir;
+	struct stat cache_stat;
+	char *attr = args[0];
+	char *val = NULL;
+	int fd = -1;
+
+	if (modify_list_attrs) {
+		sysfs_attr_list();
+		return 0;
+	}
+
+	if (!modify_set_uuid) {
+		printf("Must provide a cacheset uuid\n");
+		return -1;
+	}
+
+	snprintf(path, MAX_PATH, "%s/%s", cset_dir, modify_set_uuid);
+
+	if(!attr) {
+		printf("Must provide the name of an attribute to modify\n");
+		goto err;
+	}
+
+	enum sysfs_attr type = sysfs_attr_type(attr);
+
+	if (type == -1)
+		goto err;
+	else if(type == INTERNAL_ATTR)
+		strcat(path, "/internal");
+	else if(type == CACHE_ATTR) {
+		if(modify_dev_uuid) {
+			/* searches all cache# for a matching uuid,
+			 * path gets modified to the correct cache path */
+			char subdir[10] = "/cache";
+			err = find_matching_uuid(path, subdir,
+					modify_dev_uuid);
+			if (err) {
+				printf("Failed to find "
+					"matching dev %s\n", err);
+				goto err;
+			} else {
+				strcat(path, subdir);
+			}
+		} else {
+			printf("Must provide a device uuid\n");
+		}
+	}
+	/* SET_ATTRs are just in the current dir */
+
+	strcat(path, "/");
+	strcat(path, attr);
+
+	val = args[1];
+	if (!val) {
+		printf("Must provide a value to change the attribute to\n");
+		goto err;
+	}
+
+	fd = open(path, O_WRONLY);
+	if (fd < 0) {
+		printf("Unable to open modify attr with path %s\n", path);
+		goto err;
+	}
+
+	write(fd, val, strlen(val));
+
+err:
+	if(fd)
+		close(fd);
+	return 0;
+}
+
 int bcache_list_cachesets(NihCommand *command, char *const *args)
 {
 	char *err = NULL;
@@ -597,6 +670,10 @@ static NihCommand commands[] = {
 		"Removes a device from its cacheset",
 		N_("Removes a device from its cacheset"),
 		NULL, bcache_rm_device_options, bcache_rm_device},
+	{"modify", N_("modify --set=UUID (dev=UUID) name value"),
+		"Modifies attributes related to the cacheset",
+		N_("Modifies attributes related to the cacheset"),
+		NULL, bcache_modify_options, bcache_modify},
 	{"list-cachesets", N_("list-cachesets"),
 			   "Lists cachesets in /sys/fs/bcache",
 			   N_("Lists cachesets in /sys/fs/bcache"),