btrfs: add definitions and constants for remap-tree

Add an incompat flag for the new remap-tree feature, and the constants
and definitions needed to support it.

Reviewed-by: Boris Burkov <[e-mail]>
Signed-off-by: Mark Harmstone <[e-mail]>
Reviewed-by: David Sterba <[e-mail]>
Signed-off-by: David Sterba <[e-mail]>

fs/btrfs/accessors.h

···
 BTRFS_SETGET_STACK_FUNCS(stack_verity_descriptor_size,
 			 struct btrfs_verity_descriptor_item, size, 64);
 
+BTRFS_SETGET_FUNCS(remap_address, struct btrfs_remap_item, address, 64);
+BTRFS_SETGET_STACK_FUNCS(stack_remap_address, struct btrfs_remap_item,
+			 address, 64);
+
 /* Cast into the data area of the leaf. */
 #define btrfs_item_ptr(leaf, slot, type)				\
 	((type *)(btrfs_item_nr_offset(leaf, 0) + btrfs_item_offset(leaf, slot)))

fs/btrfs/locking.c

···
 	{ .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 = BTRFS_REMAP_TREE_OBJECTID,      DEFINE_NAME("remap") },
 	{ .id = 0,				DEFINE_NAME("tree")	},
 };
 

fs/btrfs/sysfs.c

···
 BTRFS_FEAT_ATTR_INCOMPAT(extent_tree_v2, EXTENT_TREE_V2);
 /* Remove once support for raid stripe tree is feature complete. */
 BTRFS_FEAT_ATTR_INCOMPAT(raid_stripe_tree, RAID_STRIPE_TREE);
+/* Remove once support for remap tree is feature complete. */
+BTRFS_FEAT_ATTR_INCOMPAT(remap_tree, REMAP_TREE);
 #endif
 #ifdef CONFIG_FS_VERITY
 BTRFS_FEAT_ATTR_COMPAT_RO(verity, VERITY);
···
 #ifdef CONFIG_BTRFS_EXPERIMENTAL
 	BTRFS_FEAT_ATTR_PTR(extent_tree_v2),
 	BTRFS_FEAT_ATTR_PTR(raid_stripe_tree),
+	BTRFS_FEAT_ATTR_PTR(remap_tree),
 #endif
 #ifdef CONFIG_FS_VERITY
 	BTRFS_FEAT_ATTR_PTR(verity),

fs/btrfs/tree-checker.c

···
 			  length, btrfs_stripe_nr_to_offset(U32_MAX));
 		return -EUCLEAN;
 	}
-	if (unlikely(type & ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
-			      BTRFS_BLOCK_GROUP_PROFILE_MASK))) {
+	if (unlikely(type & ~BTRFS_BLOCK_GROUP_VALID)) {
 		chunk_err(fs_info, leaf, chunk, logical,
 			  "unrecognized chunk type: 0x%llx",
-			  ~(BTRFS_BLOCK_GROUP_TYPE_MASK |
-			    BTRFS_BLOCK_GROUP_PROFILE_MASK) & type);
+			  type & ~BTRFS_BLOCK_GROUP_VALID);
 		return -EUCLEAN;
 	}
 

fs/btrfs/tree-checker.h

···
 	BTRFS_TREE_BLOCK_WRITTEN_NOT_SET,
 };
 
+
+#define BTRFS_BLOCK_GROUP_VALID	(BTRFS_BLOCK_GROUP_TYPE_MASK | \
+				 BTRFS_BLOCK_GROUP_PROFILE_MASK | \
+				 BTRFS_BLOCK_GROUP_REMAPPED)
+
 /*
  * Exported simply for btrfs-progs which wants to have the
  * btrfs_tree_block_status return codes.

fs/btrfs/volumes.c

···
 	DESCRIBE_FLAG(BTRFS_BLOCK_GROUP_DATA, "data");
 	DESCRIBE_FLAG(BTRFS_BLOCK_GROUP_SYSTEM, "system");
 	DESCRIBE_FLAG(BTRFS_BLOCK_GROUP_METADATA, "metadata");
+	DESCRIBE_FLAG(BTRFS_BLOCK_GROUP_REMAPPED, "remapped");
 
 	DESCRIBE_FLAG(BTRFS_AVAIL_ALLOC_BIT_SINGLE, "single");
 	for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)

include/uapi/linux/btrfs.h

···
 #define BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2	(1ULL << 13)
 #define BTRFS_FEATURE_INCOMPAT_RAID_STRIPE_TREE	(1ULL << 14)
 #define BTRFS_FEATURE_INCOMPAT_SIMPLE_QUOTA	(1ULL << 16)
+#define BTRFS_FEATURE_INCOMPAT_REMAP_TREE	(1ULL << 17)
 
 struct btrfs_ioctl_feature_flags {
 	__u64 compat_flags;

include/uapi/linux/btrfs_tree.h

···
 /* Tracks RAID stripes in block groups. */
 #define BTRFS_RAID_STRIPE_TREE_OBJECTID 12ULL
 
+/* Holds details of remapped addresses after relocation. */
+#define BTRFS_REMAP_TREE_OBJECTID 13ULL
+
 /* device stats in the device tree */
 #define BTRFS_DEV_STATS_OBJECTID 0ULL
 
···
 #define BTRFS_CHUNK_ITEM_KEY	228
 
 #define BTRFS_RAID_STRIPE_KEY	230
+
+#define BTRFS_IDENTITY_REMAP_KEY 	234
+#define BTRFS_REMAP_KEY		 	235
+#define BTRFS_REMAP_BACKREF_KEY	 	236
 
 /*
  * Records the overall state of the qgroups.
···
 #define BTRFS_BLOCK_GROUP_RAID6         (1ULL << 8)
 #define BTRFS_BLOCK_GROUP_RAID1C3       (1ULL << 9)
 #define BTRFS_BLOCK_GROUP_RAID1C4       (1ULL << 10)
+#define BTRFS_BLOCK_GROUP_REMAPPED      (1ULL << 11)
 #define BTRFS_BLOCK_GROUP_RESERVED	(BTRFS_AVAIL_ALLOC_BIT_SINGLE | \
 					 BTRFS_SPACE_INFO_GLOBAL_RSV)
 
···
 	 */
 	__le64 reserved[2];
 	__u8 encryption;
+} __attribute__ ((__packed__));
+
+/*
+ * For a range identified by a BTRFS_REMAP_KEY item in the remap tree, gives
+ * the address that the start of the range will get remapped to.  This
+ * structure is also shared by BTRFS_REMAP_BACKREF_KEY.
+ */
+struct btrfs_remap_item {
+	__le64 address;
 } __attribute__ ((__packed__));
 
 #endif /* _BTRFS_CTREE_H_ */