btrfs: remove raid-stripe-tree encoding field from stripe_extent

Remove the encoding field from 'struct btrfs_stripe_extent'. It was
originally intended to encode the RAID type as well as if we're a data
or a parity stripe.

But the RAID type can be inferred form the block-group and the data vs.
parity differentiation can be done easier with adding a new key type
for parity stripes in the RAID stripe tree.

Signed-off-by: Johannes Thumshirn <[e-mail]>
Signed-off-by: David Sterba <[e-mail]>

fs/btrfs/accessors.h

···
 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);
 

fs/btrfs/print-tree.c

···
 				  struct btrfs_stripe_extent *stripe)
 {
 	const int num_stripes = btrfs_num_raid_stripes(item_size);
-	const u8 encoding = btrfs_stripe_extent_encoding(eb, stripe);
-
-	pr_info("\t\t\tencoding: %s\n",
-		(encoding && encoding < BTRFS_NR_RAID_TYPES) ?
-		btrfs_raid_array[encoding].raid_name : "unknown");
 
 	for (int i = 0; i < num_stripes; i++)
 		pr_info("\t\t\tstride %d devid %llu physical %llu\n",

fs/btrfs/raid-stripe-tree.c

···
 	struct btrfs_key stripe_key;
 	struct btrfs_root *stripe_root = fs_info->stripe_root;
 	const int num_stripes = btrfs_bg_type_to_factor(bioc->map_type);
-	u8 encoding = btrfs_bg_flags_to_raid_index(bioc->map_type);
 	struct btrfs_stripe_extent *stripe_extent;
 	const size_t item_size = struct_size(stripe_extent, strides, num_stripes);
 	int ret;
···
 
 	trace_btrfs_insert_one_raid_extent(fs_info, bioc->logical, bioc->size,
 					   num_stripes);
-	btrfs_set_stack_stripe_extent_encoding(stripe_extent, encoding);
 	for (int i = 0; i < num_stripes; i++) {
 		u64 devid = bioc->stripes[i].dev->devid;
 		u64 physical = bioc->stripes[i].physical;
···
 	struct extent_buffer *leaf;
 	const u64 end = logical + *length;
 	int num_stripes;
-	u8 encoding;
 	u64 offset;
 	u64 found_logical;
 	u64 found_length;
···
 
 	num_stripes = btrfs_num_raid_stripes(btrfs_item_size(leaf, slot));
 	stripe_extent = btrfs_item_ptr(leaf, slot, struct btrfs_stripe_extent);
-	encoding = btrfs_stripe_extent_encoding(leaf, stripe_extent);
-
-	if (encoding != btrfs_bg_flags_to_raid_index(map_type)) {
-		ret = -EUCLEAN;
-		btrfs_handle_fs_error(fs_info, ret,
-				      "on-disk stripe encoding %d doesn't match RAID index %d",
-				      encoding,
-				      btrfs_bg_flags_to_raid_index(map_type));
-		goto out;
-	}
 
 	for (int i = 0; i < num_stripes; i++) {
 		struct btrfs_raid_stride *stride = &stripe_extent->strides[i];

fs/btrfs/raid-stripe-tree.h

···
 
 static inline int btrfs_num_raid_stripes(u32 item_size)
 {
-	return (item_size - offsetof(struct btrfs_stripe_extent, strides)) /
-		sizeof(struct btrfs_raid_stride);
+	return item_size / sizeof(struct btrfs_raid_stride);
 }
 
 #endif

fs/btrfs/tree-checker.c

···
 static int check_raid_stripe_extent(const struct extent_buffer *leaf,
 				    const struct btrfs_key *key, int slot)
 {
-	struct btrfs_stripe_extent *stripe_extent =
-		btrfs_item_ptr(leaf, slot, struct btrfs_stripe_extent);
-
 	if (unlikely(!IS_ALIGNED(key->objectid, leaf->fs_info->sectorsize))) {
 		generic_err(leaf, slot,
 "invalid key objectid for raid stripe extent, have %llu expect aligned to %u",
···
 	if (unlikely(!btrfs_fs_incompat(leaf->fs_info, RAID_STRIPE_TREE))) {
 		generic_err(leaf, slot,
 	"RAID_STRIPE_EXTENT present but RAID_STRIPE_TREE incompat bit unset");
-		return -EUCLEAN;
-	}
-
-	switch (btrfs_stripe_extent_encoding(leaf, stripe_extent)) {
-	case BTRFS_STRIPE_RAID0:
-	case BTRFS_STRIPE_RAID1:
-	case BTRFS_STRIPE_DUP:
-	case BTRFS_STRIPE_RAID10:
-	case BTRFS_STRIPE_RAID5:
-	case BTRFS_STRIPE_RAID6:
-	case BTRFS_STRIPE_RAID1C3:
-	case BTRFS_STRIPE_RAID1C4:
-		break;
-	default:
-		generic_err(leaf, slot, "invalid raid stripe encoding %u",
-			    btrfs_stripe_extent_encoding(leaf, stripe_extent));
 		return -EUCLEAN;
 	}
 

include/uapi/linux/btrfs_tree.h

···
 	__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[];
+	__DECLARE_FLEX_ARRAY(struct btrfs_raid_stride, strides);
 } __attribute__ ((__packed__));
 
 #define BTRFS_HEADER_FLAG_WRITTEN	(1ULL << 0)