fs: partitions: Add support for named partitions

Adds a new file in /sys/block/<block>/<partition> called partition_name
that contains the name of the partition, if specified by the partition
handler.

Change-Id: I6648ed95eabefd1d00edbfdfd99eeb971d15f4b3
Signed-off-by: Colin Cross <ccross@android.com>

2 files changed, 35 insertions, 1 deletions

diff --git a/fs/partitions/check.c b/fs/partitions/check.c
index 77e420c0d2c0..dba7af33ea3a 100644
--- a/fs/partitions/check.c
+++ b/fs/partitions/check.c
@@ -286,6 +286,13 @@ ssize_t part_inflight_show(struct device *dev,
 	return sprintf(buf, "%8u %8u\n", p->in_flight[0], p->in_flight[1]);
 }
 
+ssize_t part_partition_name_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct hd_struct *p = dev_to_part(dev);
+	return sprintf(buf, "%s\n", p->partition_name);
+}
+
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 ssize_t part_fail_show(struct device *dev,
 		       struct device_attribute *attr, char *buf)
@@ -317,6 +324,8 @@ static DEVICE_ATTR(discard_alignment, S_IRUGO, part_discard_alignment_show,
 		   NULL);
 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
+static DEVICE_ATTR(partition_name, S_IRUGO, part_partition_name_show, NULL);
+
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 static struct device_attribute dev_attr_fail =
 	__ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
@@ -330,6 +339,7 @@ static struct attribute *part_attrs[] = {
 	&dev_attr_discard_alignment.attr,
 	&dev_attr_stat.attr,
 	&dev_attr_inflight.attr,
+	&dev_attr_partition_name.attr,
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 	&dev_attr_fail.attr,
 #endif
@@ -409,6 +419,11 @@ static ssize_t whole_disk_show(struct device *dev,
 static DEVICE_ATTR(whole_disk, S_IRUSR | S_IRGRP | S_IROTH,
 		   whole_disk_show, NULL);
 
+static void name_partition(struct hd_struct *p, const char *name)
+{
+	strlcpy(p->partition_name, name, GENHD_PART_NAME_SIZE);
+}
+
 struct hd_struct *add_partition(struct gendisk *disk, int partno,
 				sector_t start, sector_t len, int flags)
 {
@@ -691,6 +706,7 @@ rescan:
 			       disk->disk_name, p, -PTR_ERR(part));
 			continue;
 		}
+		name_partition(part, state->parts[p].name);
 #ifdef CONFIG_BLK_DEV_MD
 		if (state->parts[p].flags & ADDPART_FLAG_RAID)
 			md_autodetect_dev(part_to_dev(part)->devt);
diff --git a/fs/partitions/check.h b/fs/partitions/check.h
index 8e4e103ba216..5ef9da15197b 100644
--- a/fs/partitions/check.h
+++ b/fs/partitions/check.h
@@ -1,6 +1,8 @@
 #include <linux/pagemap.h>
 #include <linux/blkdev.h>
 
+#define PART_NAME_SIZE 128
+
 /*
  * add_gd_partition adds a partitions details to the devices partition
  * description.
@@ -12,6 +14,7 @@ struct parsed_partitions {
 		sector_t from;
 		sector_t size;
 		int flags;
+		char name[PART_NAME_SIZE];
 	} parts[DISK_MAX_PARTS];
 	int next;
 	int limit;
@@ -30,7 +33,8 @@ static inline void *read_part_sector(struct parsed_partitions *state,
 }
 
 static inline void
-put_partition(struct parsed_partitions *p, int n, sector_t from, sector_t size)
+put_named_partition(struct parsed_partitions *p, int n, sector_t from,
+	sector_t size, const char *name, size_t name_size)
 {
 	if (n < p->limit) {
 		char tmp[1 + BDEVNAME_SIZE + 10 + 1];
@@ -39,8 +43,22 @@ put_partition(struct parsed_partitions *p, int n, sector_t from, sector_t size)
 		p->parts[n].size = size;
 		snprintf(tmp, sizeof(tmp), " %s%d", p->name, n);
 		strlcat(p->pp_buf, tmp, PAGE_SIZE);
+		if (name) {
+			if (name_size > PART_NAME_SIZE - 1)
+				name_size = PART_NAME_SIZE - 1;
+			memcpy(p->parts[n].name, name, name_size);
+			p->parts[n].name[name_size] = 0;
+			snprintf(tmp, sizeof(tmp), " (%s)", p->parts[n].name);
+			strlcat(p->pp_buf, tmp, PAGE_SIZE);
+		}
 	}
 }
 
+static inline void
+put_partition(struct parsed_partitions *p, int n, sector_t from, sector_t size)
+{
+	put_named_partition(p, n, from, size, NULL, 0);
+}
+
 extern int warn_no_part;