[PATCH RFC v2 2/8] btrfs: read raid-stripe-tree from disk

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

If we find a raid-stripe-tree on mount, read it from disk.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
---
 fs/btrfs/block-rsv.c       |  1 +
 fs/btrfs/ctree.h           |  1 +
 fs/btrfs/disk-io.c         | 12 ++++++++++++
 include/uapi/linux/btrfs.h |  1 +
 4 files changed, 15 insertions(+)

diff --git a/fs/btrfs/block-rsv.c b/fs/btrfs/block-rsv.c
index b3ee49b0b1e8..62c20c9d8c25 100644
--- a/fs/btrfs/block-rsv.c
+++ b/fs/btrfs/block-rsv.c
@@ -427,6 +427,7 @@ void btrfs_init_root_block_rsv(struct btrfs_root *root)
 	case BTRFS_CSUM_TREE_OBJECTID:
 	case BTRFS_EXTENT_TREE_OBJECTID:
 	case BTRFS_FREE_SPACE_TREE_OBJECTID:
+	case BTRFS_RAID_STRIPE_TREE_OBJECTID:
 		root->block_rsv = &fs_info->delayed_refs_rsv;
 		break;
 	case BTRFS_ROOT_TREE_OBJECTID:
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 18e2f186cb5e..376b9b112429 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -690,6 +690,7 @@ struct btrfs_fs_info {
 	struct btrfs_root *uuid_root;
 	struct btrfs_root *data_reloc_root;
 	struct btrfs_root *block_group_root;
+	struct btrfs_root *stripe_root;
 
 	/* the log root tree is a directory of all the other log roots */
 	struct btrfs_root *log_root_tree;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 70b388de4d66..45d1ea23a230 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1607,6 +1607,9 @@ static struct btrfs_root *btrfs_get_global_root(struct btrfs_fs_info *fs_info,
 
 		return btrfs_grab_root(root) ? root : ERR_PTR(-ENOENT);
 	}
+	if (objectid == BTRFS_RAID_STRIPE_TREE_OBJECTID)
+		return btrfs_grab_root(fs_info->stripe_root) ?
+			fs_info->stripe_root : ERR_PTR(-ENOENT);
 	return NULL;
 }
 
@@ -1679,6 +1682,7 @@ void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
 	btrfs_put_root(fs_info->fs_root);
 	btrfs_put_root(fs_info->data_reloc_root);
 	btrfs_put_root(fs_info->block_group_root);
+	btrfs_put_root(fs_info->stripe_root);
 	btrfs_check_leaked_roots(fs_info);
 	btrfs_extent_buffer_leak_debug_check(fs_info);
 	kfree(fs_info->super_copy);
@@ -2220,6 +2224,7 @@ static void free_root_pointers(struct btrfs_fs_info *info, bool free_chunk_root)
 	free_root_extent_buffers(info->fs_root);
 	free_root_extent_buffers(info->data_reloc_root);
 	free_root_extent_buffers(info->block_group_root);
+	free_root_extent_buffers(info->stripe_root);
 	if (free_chunk_root)
 		free_root_extent_buffers(info->chunk_root);
 }
@@ -2646,6 +2651,13 @@ static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
 		fs_info->uuid_root = root;
 	}
 
+	location.objectid = BTRFS_RAID_STRIPE_TREE_OBJECTID;
+	root = btrfs_read_tree_root(tree_root, &location);
+	if (!IS_ERR(root)) {
+		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
+		fs_info->stripe_root = root;
+	}
+
 	return 0;
 out:
 	btrfs_warn(fs_info, "failed to read root (objectid=%llu): %d",
diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h
index f54dc91e4025..5ca789af5beb 100644
--- a/include/uapi/linux/btrfs.h
+++ b/include/uapi/linux/btrfs.h
@@ -310,6 +310,7 @@ struct btrfs_ioctl_fs_info_args {
 #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_STRIPE_TREE	(1ULL << 14)
 
 struct btrfs_ioctl_feature_flags {
 	__u64 compat_flags;
-- 
2.35.3