Commit 2838d255 authored by Boris Burkov's avatar Boris Burkov Committed by David Sterba
Browse files

btrfs: warn when remount will not change the free space tree 



If the remount is ro->ro, rw->ro, or rw->rw, we will not create or
clear the free space tree. This can be surprising, so print a warning
to dmesg to make the failure more visible. It is also important to
ensure that the space cache options (SPACE_CACHE, FREE_SPACE_TREE) are
consistent, so ensure those are set to properly match the current on
disk state (which won't be changing).

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 04c41559

fs/btrfs/super.c

+16 −0
Original line number Diff line number Diff line
@@ -1919,6 +1919,22 @@ static int btrfs_remount(struct super_block *sb, int *flags, char *data) 
	btrfs_resize_thread_pool(fs_info,

		fs_info->thread_pool_size, old_thread_pool_size);



	if (btrfs_test_opt(fs_info, FREE_SPACE_TREE) !=

	    btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&

	    (!sb_rdonly(sb) || (*flags & SB_RDONLY))) {

		btrfs_warn(fs_info,

		"remount supports changing free space tree only from ro to rw");

		/* Make sure free space cache options match the state on disk */

		if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {

			btrfs_set_opt(fs_info->mount_opt, FREE_SPACE_TREE);

			btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);

		}

		if (btrfs_free_space_cache_v1_active(fs_info)) {

			btrfs_clear_opt(fs_info->mount_opt, FREE_SPACE_TREE);

			btrfs_set_opt(fs_info->mount_opt, SPACE_CACHE);

		}

	}



	if ((bool)(*flags & SB_RDONLY) == sb_rdonly(sb))

		goto out;