btrfs: add raid stripe tree definitions

Add definitions for the raid stripe tree. This tree will hold information
about the on-disk layout of the stripes in a RAID set.

Each stripe extent has a 1:1 relationship with an on-disk extent item and
is doing the logical to per-drive physical address translation for the
extent item in question.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/accessors.h

@@ -306,6 +306,14 @@ BTRFS_SETGET_FUNCS(timespec_nsec, struct btrfs_timespec, nsec, 32);
 BTRFS_SETGET_STACK_FUNCS(stack_timespec_sec, struct btrfs_timespec, sec, 64);
 BTRFS_SETGET_STACK_FUNCS(stack_timespec_nsec, struct btrfs_timespec, nsec, 32);
 
+BTRFS_SETGET_FUNCS(stripe_extent_encoding, struct btrfs_stripe_extent, encoding, 8);
+BTRFS_SETGET_FUNCS(raid_stride_devid, struct btrfs_raid_stride, devid, 64);
+BTRFS_SETGET_FUNCS(raid_stride_physical, struct btrfs_raid_stride, physical, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_stripe_extent_encoding,
+			 struct btrfs_stripe_extent, encoding, 8);
+BTRFS_SETGET_STACK_FUNCS(stack_raid_stride_devid, struct btrfs_raid_stride, devid, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_raid_stride_physical, struct btrfs_raid_stride, physical, 64);
+
 /* struct btrfs_dev_extent */
 BTRFS_SETGET_FUNCS(dev_extent_chunk_tree, struct btrfs_dev_extent, chunk_tree, 64);
 BTRFS_SETGET_FUNCS(dev_extent_chunk_objectid, struct btrfs_dev_extent,

fs/btrfs/locking.c

@@ -74,6 +74,7 @@ static struct btrfs_lockdep_keyset {
 	{ .id = BTRFS_UUID_TREE_OBJECTID,	DEFINE_NAME("uuid")	},
 	{ .id = BTRFS_FREE_SPACE_TREE_OBJECTID,	DEFINE_NAME("free-space") },
 	{ .id = BTRFS_BLOCK_GROUP_TREE_OBJECTID, DEFINE_NAME("block-group") },
+	{ .id = BTRFS_RAID_STRIPE_TREE_OBJECTID, DEFINE_NAME("raid-stripe") },
 	{ .id = 0,				DEFINE_NAME("tree")	},
 };
 

include/uapi/linux/btrfs_tree.h

@@ -73,6 +73,9 @@
 /* Holds the block group items for extent tree v2. */
 #define BTRFS_BLOCK_GROUP_TREE_OBJECTID 11ULL
 
+/* Tracks RAID stripes in block groups. */
+#define BTRFS_RAID_STRIPE_TREE_OBJECTID 12ULL
+
 /* device stats in the device tree */
 #define BTRFS_DEV_STATS_OBJECTID 0ULL
 
@@ -261,6 +264,8 @@
 #define BTRFS_DEV_ITEM_KEY	216
 #define BTRFS_CHUNK_ITEM_KEY	228
 
+#define BTRFS_RAID_STRIPE_KEY	230
+
 /*
  * Records the overall state of the qgroups.
  * There's only one instance of this key present,
@@ -719,6 +724,30 @@ struct btrfs_free_space_header {
 	__le64 num_bitmaps;
 } __attribute__ ((__packed__));
 
+struct btrfs_raid_stride {
+	/* The id of device this raid extent lives on. */
+	__le64 devid;
+	/* The physical location on disk. */
+	__le64 physical;
+} __attribute__ ((__packed__));
+
+/* The stripe_extent::encoding, 1:1 mapping of enum btrfs_raid_types. */
+#define BTRFS_STRIPE_RAID0	1
+#define BTRFS_STRIPE_RAID1	2
+#define BTRFS_STRIPE_DUP	3
+#define BTRFS_STRIPE_RAID10	4
+#define BTRFS_STRIPE_RAID5	5
+#define BTRFS_STRIPE_RAID6	6
+#define BTRFS_STRIPE_RAID1C3	7
+#define BTRFS_STRIPE_RAID1C4	8
+
+struct btrfs_stripe_extent {
+	__u8 encoding;
+	__u8 reserved[7];
+	/* An array of raid strides this stripe is composed of. */
+	struct btrfs_raid_stride strides[];
+} __attribute__ ((__packed__));
+
 #define BTRFS_HEADER_FLAG_WRITTEN	(1ULL << 0)
 #define BTRFS_HEADER_FLAG_RELOC		(1ULL << 1)