btrfs: Remove 'objectid' member from struct btrfs_root

There are two members in struct btrfs_root which indicate root's
objectid: objectid and root_key.objectid.

They are both set to the same value in __setup_root():

static void __setup_root(struct btrfs_root *root,
struct btrfs_fs_info *fs_info,
u64 objectid)
{
...
root->objectid = objectid;
...
root->root_key.objectid = objecitd;
...
}

and not changed to other value after initialization.

grep in btrfs directory shows both are used in many places:
$ grep -rI "root->root_key.objectid" | wc -l
133
$ grep -rI "root->objectid" | wc -l
55
(4.17, inc. some noise)

It is confusing to have two similar variable names and it seems
that there is no rule about which should be used in a certain case.

Since ->root_key itself is needed for tree reloc tree, let's remove
'objecitd' member and unify code to use ->root_key.objectid in all places.

Signed-off-by: Misono Tomohiro <[e-mail]>
Reviewed-by: Qu Wenruo <[e-mail]>
Reviewed-by: David Sterba <[e-mail]>
Signed-off-by: David Sterba <[e-mail]>

fs/btrfs/backref.c

···
 	struct seq_list elem = SEQ_LIST_INIT(elem);
 	int ret = 0;
 	struct share_check shared = {
-		.root_objectid = root->objectid,
+		.root_objectid = root->root_key.objectid,
 		.inum = inum,
 		.share_count = 0,
 	};
···
 			/* path must be released before calling iterate()! */
 			btrfs_debug(fs_root->fs_info,
 				"following ref at offset %u for inode %llu in tree %llu",
-				cur, found_key.objectid, fs_root->objectid);
+				cur, found_key.objectid,
+				fs_root->root_key.objectid);
 			ret = iterate(parent, name_len,
 				      (unsigned long)(iref + 1), eb, ctx);
 			if (ret)

fs/btrfs/btrfs_inode.h

···
 static inline unsigned long btrfs_inode_hash(u64 objectid,
 					     const struct btrfs_root *root)
 {
-	u64 h = objectid ^ (root->objectid * GOLDEN_RATIO_PRIME);
+	u64 h = objectid ^ (root->root_key.objectid * GOLDEN_RATIO_PRIME);
 
 #if BITS_PER_LONG == 32
 	h = (h >> 32) ^ (h & 0xffffffff);
···
 	struct btrfs_root *root = inode->root;
 
 	/* Output minus objectid, which is more meaningful */
-	if (root->objectid >= BTRFS_LAST_FREE_OBJECTID)
+	if (root->root_key.objectid >= BTRFS_LAST_FREE_OBJECTID)
 		btrfs_warn_rl(root->fs_info,
 	"csum failed root %lld ino %lld off %llu csum 0x%08x expected csum 0x%08x mirror %d",
-			root->objectid, btrfs_ino(inode),
+			root->root_key.objectid, btrfs_ino(inode),
 			logical_start, csum, csum_expected, mirror_num);
 	else
 		btrfs_warn_rl(root->fs_info,
 	"csum failed root %llu ino %llu off %llu csum 0x%08x expected csum 0x%08x mirror %d",
-			root->objectid, btrfs_ino(inode),
+			root->root_key.objectid, btrfs_ino(inode),
 			logical_start, csum, csum_expected, mirror_num);
 }
 

fs/btrfs/ctree.c

···
 	spin_lock(&fs_info->trans_lock);
 	if (!test_and_set_bit(BTRFS_ROOT_DIRTY, &root->state)) {
 		/* Want the extent tree to be the last on the list */
-		if (root->objectid == BTRFS_EXTENT_TREE_OBJECTID)
+		if (root->root_key.objectid == BTRFS_EXTENT_TREE_OBJECTID)
 			list_move_tail(&root->dirty_list,
 				       &fs_info->dirty_cowonly_roots);
 		else

fs/btrfs/ctree.h

···
 	int last_log_commit;
 	pid_t log_start_pid;
 
-	u64 objectid;
 	u64 last_trans;
 
 	u32 type;

fs/btrfs/delayed-inode.c

···
 	if (unlikely(ret)) {
 		btrfs_err(trans->fs_info,
 			  "err add delayed dir index item(name: %.*s) into the insertion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
-			  name_len, name, delayed_node->root->objectid,
+			  name_len, name, delayed_node->root->root_key.objectid,
 			  delayed_node->inode_id, ret);
 		BUG();
 	}
···
 	if (unlikely(ret)) {
 		btrfs_err(trans->fs_info,
 			  "err add delayed dir index item(index: %llu) into the deletion tree of the delayed node(root id: %llu, inode id: %llu, errno: %d)",
-			  index, node->root->objectid, node->inode_id, ret);
+			  index, node->root->root_key.objectid,
+			  node->inode_id, ret);
 		BUG();
 	}
 	mutex_unlock(&node->mutex);

fs/btrfs/disk-io.c

···
  * Different roots are used for different purposes and may nest inside each
  * other and they require separate keysets.  As lockdep keys should be
  * static, assign keysets according to the purpose of the root as indicated
- * by btrfs_root->objectid.  This ensures that all special purpose roots
- * have separate keysets.
+ * by btrfs_root->root_key.objectid.  This ensures that all special purpose
+ * roots have separate keysets.
  *
  * Lock-nesting across peer nodes is always done with the immediate parent
  * node locked thus preventing deadlock.  As lockdep doesn't know this, use
···
 	root->state = 0;
 	root->orphan_cleanup_state = 0;
 
-	root->objectid = objectid;
 	root->last_trans = 0;
 	root->highest_objectid = 0;
 	root->nr_delalloc_inodes = 0;

fs/btrfs/export.c

···
 	type = FILEID_BTRFS_WITHOUT_PARENT;
 
 	fid->objectid = btrfs_ino(BTRFS_I(inode));
-	fid->root_objectid = BTRFS_I(inode)->root->objectid;
+	fid->root_objectid = BTRFS_I(inode)->root->root_key.objectid;
 	fid->gen = inode->i_generation;
 
 	if (parent) {
···
 
 		fid->parent_objectid = BTRFS_I(parent)->location.objectid;
 		fid->parent_gen = parent->i_generation;
-		parent_root_id = BTRFS_I(parent)->root->objectid;
+		parent_root_id = BTRFS_I(parent)->root->root_key.objectid;
 
 		if (parent_root_id != fid->root_objectid) {
 			fid->parent_root_objectid = parent_root_id;

fs/btrfs/extent-tree.c

···
 	int level;
 	bool root_dropped = false;
 
-	btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
+	btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
 
 	path = btrfs_alloc_path();
 	if (!path) {

fs/btrfs/inode.c

···
 	int drop_inode = 0;
 
 	/* do not allow sys_link's with other subvols of the same device */
-	if (root->objectid != BTRFS_I(inode)->root->objectid)
+	if (root->root_key.objectid != BTRFS_I(inode)->root->root_key.objectid)
 		return -EXDEV;
 
 	if (inode->i_nlink >= BTRFS_LINK_MAX)

fs/btrfs/ioctl.c

···
 		ret = PTR_ERR(new_root);
 		goto out;
 	}
-	if (!is_fstree(new_root->objectid)) {
+	if (!is_fstree(new_root->root_key.objectid)) {
 		ret = -ENOENT;
 		goto out;
 	}

fs/btrfs/qgroup.c

···
 	int ret;
 
 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &root->fs_info->flags) ||
-	    !is_fstree(root->objectid) || len == 0)
+	    !is_fstree(root->root_key.objectid) || len == 0)
 		return 0;
 
 	/* @reserved parameter is mandatory for qgroup */
···
 			goto out;
 		freed += changeset.bytes_changed;
 	}
-	btrfs_qgroup_free_refroot(root->fs_info, root->objectid, freed,
+	btrfs_qgroup_free_refroot(root->fs_info, root->root_key.objectid, freed,
 				  BTRFS_QGROUP_RSV_DATA);
 	ret = freed;
 out:
···
 					changeset.bytes_changed, trace_op);
 	if (free)
 		btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
-				BTRFS_I(inode)->root->objectid,
+				BTRFS_I(inode)->root->root_key.objectid,
 				changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
 	ret = changeset.bytes_changed;
 out:
···
 	int ret;
 
 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
-	    !is_fstree(root->objectid) || num_bytes == 0)
+	    !is_fstree(root->root_key.objectid) || num_bytes == 0)
 		return 0;
 
 	BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
···
 	struct btrfs_fs_info *fs_info = root->fs_info;
 
 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
-	    !is_fstree(root->objectid))
+	    !is_fstree(root->root_key.objectid))
 		return;
 
 	/* TODO: Update trace point to handle such free */
 	trace_qgroup_meta_free_all_pertrans(root);
 	/* Special value -1 means to free all reserved space */
-	btrfs_qgroup_free_refroot(fs_info, root->objectid, (u64)-1,
+	btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid, (u64)-1,
 				  BTRFS_QGROUP_RSV_META_PERTRANS);
 }
 
···
 	struct btrfs_fs_info *fs_info = root->fs_info;
 
 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
-	    !is_fstree(root->objectid))
+	    !is_fstree(root->root_key.objectid))
 		return;
 
 	/*
···
 	num_bytes = sub_root_meta_rsv(root, num_bytes, type);
 	BUG_ON(num_bytes != round_down(num_bytes, fs_info->nodesize));
 	trace_qgroup_meta_reserve(root, type, -(s64)num_bytes);
-	btrfs_qgroup_free_refroot(fs_info, root->objectid, num_bytes, type);
+	btrfs_qgroup_free_refroot(fs_info, root->root_key.objectid,
+				  num_bytes, type);
 }
 
 static void qgroup_convert_meta(struct btrfs_fs_info *fs_info, u64 ref_root,
···
 	struct btrfs_fs_info *fs_info = root->fs_info;
 
 	if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) ||
-	    !is_fstree(root->objectid))
+	    !is_fstree(root->root_key.objectid))
 		return;
 	/* Same as btrfs_qgroup_free_meta_prealloc() */
 	num_bytes = sub_root_meta_rsv(root, num_bytes,
 				      BTRFS_QGROUP_RSV_META_PREALLOC);
 	trace_qgroup_meta_convert(root, num_bytes);
-	qgroup_convert_meta(fs_info, root->objectid, num_bytes);
+	qgroup_convert_meta(fs_info, root->root_key.objectid, num_bytes);
 }
 
 /*
···
 				inode->i_ino, unode->val, unode->aux);
 		}
 		btrfs_qgroup_free_refroot(BTRFS_I(inode)->root->fs_info,
-				BTRFS_I(inode)->root->objectid,
+				BTRFS_I(inode)->root->root_key.objectid,
 				changeset.bytes_changed, BTRFS_QGROUP_RSV_DATA);
 
 	}

fs/btrfs/ref-verify.c

···
 
 	INIT_LIST_HEAD(&ra->list);
 	ra->action = action;
-	ra->root = root->objectid;
+	ra->root = root->root_key.objectid;
 
 	/*
 	 * This is an allocation, preallocate the block_entry in case we haven't
···
 			 * one we want to lookup below when we modify the
 			 * re->num_refs.
 			 */
-			ref_root = root->objectid;
-			re->root_objectid = root->objectid;
+			ref_root = root->root_key.objectid;
+			re->root_objectid = root->root_key.objectid;
 			re->num_refs = 0;
 		}
 
···
 			 * didn't thik of some other corner case.
 			 */
 			btrfs_err(fs_info, "failed to find root %llu for %llu",
-				  root->objectid, be->bytenr);
+				  root->root_key.objectid, be->bytenr);
 			dump_block_entry(fs_info, be);
 			dump_ref_action(fs_info, ra);
 			kfree(ra);

fs/btrfs/relocation.c

···
 		    cur->bytenr) {
 			btrfs_err(root->fs_info,
 	"couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
-				  cur->bytenr, level - 1, root->objectid,
+				  cur->bytenr, level - 1,
+				  root->root_key.objectid,
 				  node_key->objectid, node_key->type,
 				  node_key->offset);
 			err = -ENOENT;

fs/btrfs/send.c

···
 	u64 root = (u64)(uintptr_t)key;
 	struct clone_root *cr = (struct clone_root *)elt;
 
-	if (root < cr->root->objectid)
+	if (root < cr->root->root_key.objectid)
 		return -1;
-	if (root > cr->root->objectid)
+	if (root > cr->root->root_key.objectid)
 		return 1;
 	return 0;
 }
···
 	struct clone_root *cr1 = (struct clone_root *)e1;
 	struct clone_root *cr2 = (struct clone_root *)e2;
 
-	if (cr1->root->objectid < cr2->root->objectid)
+	if (cr1->root->root_key.objectid < cr2->root->root_key.objectid)
 		return -1;
-	if (cr1->root->objectid > cr2->root->objectid)
+	if (cr1->root->root_key.objectid > cr2->root->root_key.objectid)
 		return 1;
 	return 0;
 }
···
 		return -ENOMEM;
 	}
 
-	key.objectid = send_root->objectid;
+	key.objectid = send_root->root_key.objectid;
 	key.type = BTRFS_ROOT_BACKREF_KEY;
 	key.offset = 0;
 
···
 	leaf = path->nodes[0];
 	btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 	if (key.type != BTRFS_ROOT_BACKREF_KEY ||
-	    key.objectid != send_root->objectid) {
+	    key.objectid != send_root->root_key.objectid) {
 		ret = -ENOENT;
 		goto out;
 	}
···
 
 	btrfs_debug(sctx->send_root->fs_info,
 		    "send_clone offset=%llu, len=%d, clone_root=%llu, clone_inode=%llu, clone_offset=%llu",
-		    offset, len, clone_root->root->objectid, clone_root->ino,
-		    clone_root->offset);
+		    offset, len, clone_root->root->root_key.objectid,
+		    clone_root->ino, clone_root->offset);
 
 	p = fs_path_alloc();
 	if (!p)

fs/btrfs/super.c

···
 	buf->f_fsid.val[0] = be32_to_cpu(fsid[0]) ^ be32_to_cpu(fsid[2]);
 	buf->f_fsid.val[1] = be32_to_cpu(fsid[1]) ^ be32_to_cpu(fsid[3]);
 	/* Mask in the root object ID too, to disambiguate subvols */
-	buf->f_fsid.val[0] ^= BTRFS_I(d_inode(dentry))->root->objectid >> 32;
-	buf->f_fsid.val[1] ^= BTRFS_I(d_inode(dentry))->root->objectid;
+	buf->f_fsid.val[0] ^=
+		BTRFS_I(d_inode(dentry))->root->root_key.objectid >> 32;
+	buf->f_fsid.val[1] ^=
+		BTRFS_I(d_inode(dentry))->root->root_key.objectid;
 
 	return 0;
 }

fs/btrfs/transaction.c

···
 		list_del_init(&root->dirty_list);
 		free_extent_buffer(root->commit_root);
 		root->commit_root = btrfs_root_node(root);
-		if (is_fstree(root->objectid))
+		if (is_fstree(root->root_key.objectid))
 			btrfs_unpin_free_ino(root);
 		clear_btree_io_tree(&root->dirty_log_pages);
 	}
···
 	list_del_init(&root->root_list);
 	spin_unlock(&fs_info->trans_lock);
 
-	btrfs_debug(fs_info, "cleaner removing %llu", root->objectid);
+	btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
 
 	btrfs_kill_all_delayed_nodes(root);
 

include/trace/events/btrfs.h

···
 	),
 
 	TP_fast_assign_btrfs(bi->root->fs_info,
-		__entry->root_obj	= bi->root->objectid;
+		__entry->root_obj	= bi->root->root_key.objectid;
 		__entry->ino		= btrfs_ino(bi);
 		__entry->isize		= bi->vfs_inode.i_size;
 		__entry->disk_isize	= bi->disk_i_size;
···
 
 	TP_fast_assign_btrfs(
 		bi->root->fs_info,
-		__entry->root_obj	= bi->root->objectid;
+		__entry->root_obj	= bi->root->root_key.objectid;
 		__entry->ino		= btrfs_ino(bi);
 		__entry->isize		= bi->vfs_inode.i_size;
 		__entry->disk_isize	= bi->disk_i_size;
···
 	),
 
 	TP_fast_assign_btrfs(btrfs_sb(inode->i_sb),
-		__entry->rootid		= BTRFS_I(inode)->root->objectid;
+		__entry->rootid		=
+			BTRFS_I(inode)->root->root_key.objectid;
 		__entry->ino		= btrfs_ino(BTRFS_I(inode));
 		__entry->start		= start;
 		__entry->len		= len;
···
 	),
 
 	TP_fast_assign_btrfs(root->fs_info,
-		__entry->refroot	= root->objectid;
+		__entry->refroot	= root->root_key.objectid;
 		__entry->diff		= diff;
 	),
 
···
 	),
 
 	TP_fast_assign_btrfs(root->fs_info,
-		__entry->refroot	= root->objectid;
+		__entry->refroot	= root->root_key.objectid;
 		__entry->diff		= diff;
 	),
 
···
 	),
 
 	TP_fast_assign_btrfs(root->fs_info,
-		__entry->refroot	= root->objectid;
+		__entry->refroot	= root->root_key.objectid;
 		spin_lock(&root->qgroup_meta_rsv_lock);
 		__entry->diff		= -(s64)root->qgroup_meta_rsv_pertrans;
 		spin_unlock(&root->qgroup_meta_rsv_lock);
···
 	),
 
 	TP_fast_assign_btrfs(root->fs_info,
-		__entry->root_objectid	= root->objectid;
+		__entry->root_objectid	= root->root_key.objectid;
 		__entry->ino		= ino;
 		__entry->mod		= mod;
 	),