btrfs-progs: read fs with stripe tree from disk

When encountering a filesystem formatted with the raid stripe tree
feature, read it from disk.

Also add the incompat declaration to the tree printer.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

kernel-shared/ctree.h

@@ -306,6 +306,7 @@ struct btrfs_fs_info {
 	struct btrfs_root *quota_root;
 	struct btrfs_root *uuid_root;
 	struct btrfs_root *block_group_root;
+	struct btrfs_root *stripe_root;
 
 	struct rb_root global_roots_tree;
 	struct rb_root fs_root_tree;

kernel-shared/disk-io.c

@@ -790,6 +790,9 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 		return fs_info->block_group_root ? fs_info->block_group_root :
 						ERR_PTR(-ENOENT);
 
+	if (location->objectid == BTRFS_RAID_STRIPE_TREE_OBJECTID)
+		return fs_info->stripe_root ? fs_info->stripe_root : ERR_PTR(-ENOENT);
+
 	BUG_ON(location->objectid == BTRFS_TREE_RELOC_OBJECTID);
 
 	node = rb_search(&fs_info->fs_root_tree, (void *)&objectid,
@@ -822,6 +825,9 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
 	if (fs_info->quota_root)
 		free(fs_info->quota_root);
 
+	if (fs_info->stripe_root)
+		free(fs_info->stripe_root);
+
 	free_global_roots_tree(&fs_info->global_roots_tree);
 	free(fs_info->tree_root);
 	free(fs_info->chunk_root);
@@ -846,12 +852,14 @@ struct btrfs_fs_info *btrfs_new_fs_info(int writable, u64 sb_bytenr)
 	fs_info->dev_root = calloc(1, sizeof(struct btrfs_root));
 	fs_info->quota_root = calloc(1, sizeof(struct btrfs_root));
 	fs_info->uuid_root = calloc(1, sizeof(struct btrfs_root));
+	fs_info->stripe_root = calloc(1, sizeof(struct btrfs_root));
 	fs_info->block_group_root = calloc(1, sizeof(struct btrfs_root));
 	fs_info->super_copy = calloc(1, BTRFS_SUPER_INFO_SIZE);
 
 	if (!fs_info->tree_root || !fs_info->chunk_root || !fs_info->dev_root ||
 	    !fs_info->quota_root || !fs_info->uuid_root ||
-	    !fs_info->block_group_root || !fs_info->super_copy)
+	    !fs_info->block_group_root || !fs_info->super_copy ||
+	    !fs_info->stripe_root)
 		goto free_all;
 
 	extent_buffer_init_cache(fs_info);
@@ -1260,6 +1268,20 @@ int btrfs_setup_all_roots(struct btrfs_fs_info *fs_info, u64 root_tree_bytenr,
 			return -EIO;
 	}
 
+#if EXPERIMENTAL
+	if (btrfs_fs_incompat(fs_info, RAID_STRIPE_TREE)) {
+		ret = btrfs_find_and_setup_root(root, fs_info,
+						BTRFS_RAID_STRIPE_TREE_OBJECTID,
+						fs_info->stripe_root);
+		if (ret) {
+			free(fs_info->stripe_root);
+			fs_info->stripe_root = NULL;
+		} else {
+			set_bit(BTRFS_ROOT_TRACK_DIRTY, &fs_info->stripe_root->state);
+		}
+	}
+#endif
+
 	if (maybe_load_block_groups(fs_info, flags)) {
 		ret = btrfs_read_block_groups(fs_info);
 		/*
@@ -1317,6 +1339,8 @@ void btrfs_release_all_roots(struct btrfs_fs_info *fs_info)
 		free_extent_buffer(fs_info->chunk_root->node);
 	if (fs_info->uuid_root)
 		free_extent_buffer(fs_info->uuid_root->node);
+	if (fs_info->stripe_root)
+		free_extent_buffer(fs_info->stripe_root->node);
 }
 
 static void free_map_lookup(struct cache_extent *ce)

kernel-shared/print-tree.c

@@ -1708,6 +1708,7 @@ static struct readable_flag_entry incompat_flags_array[] = {
 	DEF_INCOMPAT_FLAG_ENTRY(RAID1C34),
 	DEF_INCOMPAT_FLAG_ENTRY(ZONED),
 	DEF_INCOMPAT_FLAG_ENTRY(EXTENT_TREE_V2),
+	DEF_INCOMPAT_FLAG_ENTRY(RAID_STRIPE_TREE),
 };
 static const int incompat_flags_num = sizeof(incompat_flags_array) /
 				      sizeof(struct readable_flag_entry);

kernel-shared/uapi/btrfs.h

@@ -356,6 +356,7 @@ _static_assert(sizeof(struct btrfs_ioctl_fs_info_args) == 1024);
 #define BTRFS_FEATURE_INCOMPAT_RAID1C34		(1ULL << 11)
 #define BTRFS_FEATURE_INCOMPAT_ZONED		(1ULL << 12)
 #define BTRFS_FEATURE_INCOMPAT_EXTENT_TREE_V2	(1ULL << 13)
+#define BTRFS_FEATURE_INCOMPAT_RAID_STRIPE_TREE (1ULL << 14)
 
 struct btrfs_ioctl_feature_flags {
 	__u64 compat_flags;

kernel-shared/uapi/btrfs_tree.h

@@ -73,6 +73,9 @@
 /* Holds the block group items for extent tree v2. */
 #define BTRFS_BLOCK_GROUP_TREE_OBJECTID 11ULL
 
+/* Holds raid stripe entries */
+#define BTRFS_RAID_STRIPE_TREE_OBJECTID 12ULL
+
 /* device stats in the device tree */
 #define BTRFS_DEV_STATS_OBJECTID 0ULL