Commit 8b228324 authored by Boris Burkov's avatar Boris Burkov Committed by David Sterba
Browse files

btrfs: clear free space tree on ro->rw remount 



A user might want to revert to v1 or nospace_cache on a root filesystem,
and much like turning on the free space tree, that can only be done
remounting from ro->rw. Support clearing the free space tree on such
mounts by moving it into the shared remount logic.

Since the CLEAR_CACHE option sticks around across remounts, this change
would result in clearing the tree for ever on every remount, which is
not desirable. To fix that, add CLEAR_CACHE to the oneshot options we
clear at mount end, which has the other bonus of not cluttering the
/proc/mounts output with clear_cache.

Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarBoris Burkov <boris@bur.io>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 8cd29088

fs/btrfs/disk-io.c

+21 −21
Original line number Diff line number Diff line
@@ -2878,6 +2878,7 @@ static int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info) 
void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info)

{

	btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);

	btrfs_clear_opt(fs_info->mount_opt, CLEAR_CACHE);

}



/*
@@ -2887,6 +2888,26 @@ void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info) 
int btrfs_start_pre_rw_mount(struct btrfs_fs_info *fs_info)

{

	int ret;

	bool clear_free_space_tree = false;



	if (btrfs_test_opt(fs_info, CLEAR_CACHE) &&

	    btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {

		clear_free_space_tree = true;

	} else if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&

		   !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID)) {

		btrfs_warn(fs_info, "free space tree is invalid");

		clear_free_space_tree = true;

	}



	if (clear_free_space_tree) {

		btrfs_info(fs_info, "clearing free space tree");

		ret = btrfs_clear_free_space_tree(fs_info);

		if (ret) {

			btrfs_warn(fs_info,

				   "failed to clear free space tree: %d", ret);

			goto out;

		}

	}



	ret = btrfs_cleanup_fs_roots(fs_info);

	if (ret)
@@ -2960,7 +2981,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device 
	struct btrfs_root *chunk_root;

	int ret;

	int err = -EINVAL;

	int clear_free_space_tree = 0;

	int level;



	ret = init_mount_fs_info(fs_info, sb);
@@ -3371,26 +3391,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device 
	if (sb_rdonly(sb))

		goto clear_oneshot;



	if (btrfs_test_opt(fs_info, CLEAR_CACHE) &&

	    btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {

		clear_free_space_tree = 1;

	} else if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&

		   !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID)) {

		btrfs_warn(fs_info, "free space tree is invalid");

		clear_free_space_tree = 1;

	}



	if (clear_free_space_tree) {

		btrfs_info(fs_info, "clearing free space tree");

		ret = btrfs_clear_free_space_tree(fs_info);

		if (ret) {

			btrfs_warn(fs_info,

				   "failed to clear free space tree: %d", ret);

			close_ctree(fs_info);

			return ret;

		}

	}



	ret = btrfs_start_pre_rw_mount(fs_info);

	if (ret) {

		close_ctree(fs_info);