block, partition: add partition_meta_info to hd_struct

I'm reposting this patch series as v4 since there have been no additional
comments, and I cleaned up one extra bit of unneeded code (in 3/3). The patches
are against Linus's tree: 2bfc96a127bc1cc94d26bfaa40159966064f9c8c
(2.6.36-rc3).

Would this patchset be suitable for inclusion in an mm branch?

This changes adds a partition_meta_info struct which itself contains a
union of structures that provide partition table specific metadata.

This change leaves the union empty. The subsequent patch includes an
implementation for CONFIG_EFI_PARTITION-based metadata.

Signed-off-by: Will Drewry <wad@chromium.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 51 insertions, 2 deletions

diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 5f2f4c4d8fb0..66e26b5a1537 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -12,6 +12,7 @@
 #include <linux/types.h>
 #include <linux/kdev_t.h>
 #include <linux/rcupdate.h>
+#include <linux/slab.h>
 
 #ifdef CONFIG_BLOCK
 
@@ -86,7 +87,15 @@ struct disk_stats {
         unsigned long io_ticks;
         unsigned long time_in_queue;
 };
-        
+
+#define PARTITION_META_INFO_VOLNAMELTH  64
+#define PARTITION_META_INFO_UUIDLTH     16
+
+struct partition_meta_info {
+        u8 uuid[PARTITION_META_INFO_UUIDLTH];   /* always big endian */
+        u8 volname[PARTITION_META_INFO_VOLNAMELTH];
+};
+
 struct hd_struct {
         sector_t start_sect;
         sector_t nr_sects;
@@ -95,6 +104,7 @@ struct hd_struct {
         struct device __dev;
         struct kobject *holder_dir;
         int policy, partno;
+        struct partition_meta_info *info;
 #ifdef CONFIG_FAIL_MAKE_REQUEST
         int make_it_fail;
 #endif
@@ -181,6 +191,30 @@ static inline struct gendisk *part_to_disk(struct hd_struct *part)
         return NULL;
 }
 
+static inline void part_pack_uuid(const u8 *uuid_str, u8 *to)
+{
+        int i;
+        for (i = 0; i < 16; ++i) {
+                *to++ = (hex_to_bin(*uuid_str) << 4) |
+                        (hex_to_bin(*(uuid_str + 1)));
+                uuid_str += 2;
+                switch (i) {
+                case 3:
+                case 5:
+                case 7:
+                case 9:
+                        uuid_str++;
+                        continue;
+                }
+        }
+}
+
+static inline char *part_unpack_uuid(const u8 *uuid, char *out)
+{
+        sprintf(out, "%pU", uuid);
+        return out;
+}
+
 static inline int disk_max_parts(struct gendisk *disk)
 {
         if (disk->flags & GENHD_FL_EXT_DEVT)
@@ -342,6 +376,19 @@ static inline int part_in_flight(struct hd_struct *part)
         return part->in_flight[0] + part->in_flight[1];
 }
 
+static inline struct partition_meta_info *alloc_part_info(struct gendisk *disk)
+{
+        if (disk)
+                return kzalloc_node(sizeof(struct partition_meta_info),
+                                    GFP_KERNEL, disk->node_id);
+        return kzalloc(sizeof(struct partition_meta_info), GFP_KERNEL);
+}
+
+static inline void free_part_info(struct hd_struct *part)
+{
+        kfree(part->info);
+}
+
 /* block/blk-core.c */
 extern void part_round_stats(int cpu, struct hd_struct *part);
 
@@ -533,7 +580,9 @@ extern int disk_expand_part_tbl(struct gendisk *disk, int target);
 extern int rescan_partitions(struct gendisk *disk, struct block_device *bdev);
 extern struct hd_struct * __must_check add_partition(struct gendisk *disk,
                                                      int partno, sector_t start,
-                                                     sector_t len, int flags);
+                                                     sector_t len, int flags,
+                                                     struct partition_meta_info
+                                                       *info);
 extern void delete_partition(struct gendisk *, int);
 extern void printk_all_partitions(void);