Commit 33d85fda authored Oct 31, 2017 by Qu Wenruo Committed by David Sterba Jan 22, 2018

btrfs: Don't generate UUID for non-fs tree



btrfs_create_tree() will unconditionally generate UUID for any root.
So for quota tree and data reloc tree created by kernel, they will have
unique UUIDs.

However UUID in root item is only referred by UUID tree, which only
records UUID for fs trees.  This makes unique UUIDs for quota/data reloc
tree meaningless.

Leave the UUID as zero for non-fs tree, making btrfs-debug-tree output
less confusing.

Reported-by: Misono Tomohiro <misono.tomohiro@jp.fujitsu.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

parent 2c997384

fs/btrfs/disk-io.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -1243,7 +1243,7 @@ struct btrfs_root btrfs_create_tree(struct btrfs_trans_handle trans,
		struct btrfs_root *root;
		struct btrfs_key key;
		int ret = 0;
		uuid_le uuid;
		uuid_le uuid = NULL_UUID_LE;

		root = btrfs_alloc_root(fs_info, GFP_KERNEL);
		if (!root)
		@@ -1284,6 +1284,7 @@ struct btrfs_root btrfs_create_tree(struct btrfs_trans_handle trans,
		btrfs_set_root_used(&root->root_item, leaf->len);
		btrfs_set_root_last_snapshot(&root->root_item, 0);
		btrfs_set_root_dirid(&root->root_item, 0);
		if (is_fstree(objectid))
		uuid_le_gen(&uuid);
		memcpy(root->root_item.uuid, uuid.b, BTRFS_UUID_SIZE);
		root->root_item.drop_level = 0;

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