From 2838d255cb9b85a845efc3bbd3f6fc66ed883d35 Mon Sep 17 00:00:00 2001 From: Boris Burkov Date: Wed, 18 Nov 2020 15:06:24 -0800 Subject: [PATCH] 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: Josef Bacik Signed-off-by: Boris Burkov Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/super.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index bd3ce2b43838..022f20810089 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -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; -- GitLab