Util: get device size from id

Signed-off-by: Anna Czarnowska <anna.czarnowska@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>

2 files changed, 17 insertions, 0 deletions

diff --git a/mdadm.h b/mdadm.h
index 6c6e352d..6b54249f 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -747,6 +747,7 @@ static inline struct supertype *guess_super(int fd) {
 extern struct supertype *dup_super(struct supertype *st);
 extern int get_dev_size(int fd, char *dname, unsigned long long *sizep);
 extern int must_be_container(int fd);
+extern int dev_size_from_id(unsigned id, unsigned long long *size);
 extern void get_one_disk(int mdfd, mdu_array_info_t *ainf,
 			 mdu_disk_info_t *disk);
 void wait_for(char *dev, int fd);
diff --git a/util.c b/util.c
index ac5d8b13..1ecce3b8 100644
--- a/util.c
+++ b/util.c
@@ -1094,6 +1094,22 @@ struct supertype *super_by_fd(int fd, char **subarrayp)
 }
 #endif /* !defined(MDASSEMBLE) || defined(MDASSEMBLE) && defined(MDASSEMBLE_AUTO) */
 
+int dev_size_from_id(unsigned int id, unsigned long long *size)
+{
+	char buf[20];
+	int fd;
+
+	sprintf(buf, "%d:%d", major(id), minor(id));
+	fd = dev_open(buf, O_RDONLY);
+	if (fd < 0)
+		return 0;
+	if (get_dev_size(fd, NULL, size)) {
+		close(fd);
+		return 1;
+	}
+	close(fd);
+	return 0;
+}
 
 struct supertype *dup_super(struct supertype *orig)
 {