From 5011139a4718455a6cd6214fd84e6f8500fd3874 Mon Sep 17 00:00:00 2001 From: Boris Burkov Date: Wed, 18 Nov 2020 15:06:19 -0800 Subject: [PATCH] btrfs: create free space tree on ro->rw remount When a user attempts to remount a btrfs filesystem with 'mount -o remount,space_cache=v2', that operation silently succeeds. Unfortunately, this is misleading, because the remount does not create the free space tree. /proc/mounts will incorrectly show space_cache=v2, but on the next mount, the file system will revert to the old space_cache. For now, we handle only the easier case, where the existing mount is read-only and the new mount is read-write. In that case, we can create the free space tree without contending with the block groups changing as we go. Reviewed-by: Josef Bacik Signed-off-by: Boris Burkov Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/disk-io.c | 23 +++++++++++------------ 1 file changed, 11 insertions(+), 12 deletions(-) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 0d076437b72e..a3e0065bf635 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2898,6 +2898,17 @@ int btrfs_start_pre_rw_mount(struct btrfs_fs_info *fs_info) goto out; } + if (btrfs_test_opt(fs_info, FREE_SPACE_TREE) && + !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) { + btrfs_info(fs_info, "creating free space tree"); + ret = btrfs_create_free_space_tree(fs_info); + if (ret) { + btrfs_warn(fs_info, + "failed to create free space tree: %d", ret); + goto out; + } + } + ret = btrfs_resume_balance_async(fs_info); if (ret) goto out; @@ -3370,18 +3381,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device } } - if (btrfs_test_opt(fs_info, FREE_SPACE_TREE) && - !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) { - btrfs_info(fs_info, "creating free space tree"); - ret = btrfs_create_free_space_tree(fs_info); - if (ret) { - btrfs_warn(fs_info, - "failed to create 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); -- 2.11.0