[PATCH v4 2/6] btrfs-progs: read fs with stripe tree from disk

[Johannes Thumshirn <johannes.thumshirn@wdc.com>]

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>
---
 kernel-shared/ctree.h           |  1 +
 kernel-shared/disk-io.c         | 28 +++++++++++++++++++++++++++-
 kernel-shared/print-tree.c      |  1 +
 kernel-shared/uapi/btrfs.h      |  1 +
 kernel-shared/uapi/btrfs_tree.h |  3 +++
 5 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/kernel-shared/ctree.h b/kernel-shared/ctree.h
index 5d3392ae82a6..035358436d8f 100644
--- a/kernel-shared/ctree.h
+++ b/kernel-shared/ctree.h
@@ -298,6 +298,7 @@ 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;
diff --git a/kernel-shared/disk-io.c b/kernel-shared/disk-io.c
index 442d3af8bc01..3ab32f7ad910 100644
--- a/kernel-shared/disk-io.c
+++ b/kernel-shared/disk-io.c
@@ -790,6 +790,10 @@ 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 +826,9 @@ 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 +853,14 @@ 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 +1269,21 @@ 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 +1341,8 @@ 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)
diff --git a/kernel-shared/print-tree.c b/kernel-shared/print-tree.c
index 0f7f7b72f96a..3eff82b364ef 100644
--- a/kernel-shared/print-tree.c
+++ b/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);
diff --git a/kernel-shared/uapi/btrfs.h b/kernel-shared/uapi/btrfs.h
index 85b04f89a2a9..c750b7aa921f 100644
--- a/kernel-shared/uapi/btrfs.h
+++ b/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;
diff --git a/kernel-shared/uapi/btrfs_tree.h b/kernel-shared/uapi/btrfs_tree.h
index 73411a8697ce..b76b1660f38b 100644
--- a/kernel-shared/uapi/btrfs_tree.h
+++ b/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
 

-- 
2.41.0