@@ -3121,23 +3121,34 @@ int btrfs_start_pre_rw_mount(struct btrfs_fs_info *fs_info)
{
int ret;
const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
- bool clear_free_space_tree = false;
+ bool rebuild_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;
+ rebuild_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;
+ rebuild_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 (rebuild_free_space_tree) {
+ btrfs_info(fs_info, "rebuilding free space tree");
+ ret = btrfs_rebuild_free_space_tree(fs_info);
if (ret) {
btrfs_warn(fs_info,
- "failed to clear free space tree: %d", ret);
+ "failed to rebuild free space tree: %d", ret);
+ goto out;
+ }
+ }
+
+ if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
+ !btrfs_test_opt(fs_info, FREE_SPACE_TREE)) {
+ btrfs_info(fs_info, "disabling free space tree");
+ ret = btrfs_delete_free_space_tree(fs_info);
+ if (ret) {
+ btrfs_warn(fs_info,
+ "failed to disable free space tree: %d", ret);
goto out;
}
}
@@ -1252,7 +1252,7 @@ static int clear_free_space_tree(struct btrfs_trans_handle *trans,
return ret;
}
-int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
+int btrfs_delete_free_space_tree(struct btrfs_fs_info *fs_info)
{
struct btrfs_trans_handle *trans;
struct btrfs_root *tree_root = fs_info->tree_root;
@@ -1298,6 +1298,54 @@ int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
return ret;
}
+int btrfs_rebuild_free_space_tree(struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_trans_handle *trans;
+ struct btrfs_key key = {
+ .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID,
+ .type = BTRFS_ROOT_ITEM_KEY,
+ .offset = 0,
+ };
+ struct btrfs_root *free_space_root = btrfs_global_root(fs_info, &key);
+ struct rb_node *node;
+ int ret;
+
+ trans = btrfs_start_transaction(free_space_root, 1);
+ if (IS_ERR(trans))
+ return PTR_ERR(trans);
+
+ set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
+ set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
+
+ ret = clear_free_space_tree(trans, free_space_root);
+ if (ret)
+ goto abort;
+
+ node = rb_first_cached(&fs_info->block_group_cache_tree);
+ while (node) {
+ struct btrfs_block_group *block_group;
+
+ block_group = rb_entry(node, struct btrfs_block_group,
+ cache_node);
+ ret = populate_free_space_tree(trans, block_group);
+ if (ret)
+ goto abort;
+ node = rb_next(node);
+ }
+
+ btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
+ btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
+ clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
+
+ ret = btrfs_commit_transaction(trans);
+ clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
+ return ret;
+abort:
+ btrfs_abort_transaction(trans, ret);
+ btrfs_end_transaction(trans);
+ return ret;
+}
+
static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
struct btrfs_block_group *block_group,
struct btrfs_path *path)
@@ -18,7 +18,8 @@ struct btrfs_caching_control;
void set_free_space_tree_thresholds(struct btrfs_block_group *block_group);
int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info);
-int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info);
+int btrfs_delete_free_space_tree(struct btrfs_fs_info *fs_info);
+int btrfs_rebuild_free_space_tree(struct btrfs_fs_info *fs_info);
int load_free_space_tree(struct btrfs_caching_control *caching_ctl);
int add_block_group_free_space(struct btrfs_trans_handle *trans,
struct btrfs_block_group *block_group);
@@ -828,8 +828,7 @@ int btrfs_parse_options(struct btrfs_fs_info *info, char *options,
ret = -EINVAL;
}
if (btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE) &&
- (btrfs_test_opt(info, CLEAR_CACHE) ||
- !btrfs_test_opt(info, FREE_SPACE_TREE))) {
+ !btrfs_test_opt(info, FREE_SPACE_TREE)) {
btrfs_err(info, "cannot disable free space tree with block-group-tree feature");
ret = -EINVAL;
}
Previously clear_cache mount option would simply disable free-space-tree feature temporarily then re-enable it to rebuild the whole free space tree. But this is problematic for block-group-tree feature, as we have an artificial dependency on free-space-tree feature. If we go the existing method, after clearing the free-space-tree feature, we would flip the filesystem to read-only mode, as we detects a super block write with block-group-tree but no free-space-tree feature. This patch would change the behavior by properly rebuilding the free space tree without disabling this feature, thus allowing clear_cache mount option to work with block group tree. Now we can mount a filesystem with block-group-tree feature and clear_mount option: $ mkfs.btrfs -O block-group-tree /dev/test/scratch1 -f $ sudo mount /dev/test/scratch1 /mnt/btrfs -o clear_cache $ sudo dmesg -t | head -n 5 BTRFS info (device dm-1): force clearing of disk cache BTRFS info (device dm-1): using free space tree BTRFS info (device dm-1): auto enabling async discard BTRFS info (device dm-1): rebuilding free space tree BTRFS info (device dm-1): checking UUID tree Signed-off-by: Qu Wenruo <wqu@suse.com> --- Currently this patch is dependent on the patch "btrfs: properly reject clear_cache and v1 cache for block-group-tree". The size of the patch makes me wonder if it's a good candidate for backports. It's at my personal border line for patch sizes. But if we choose to backport this patch (with the dependency), then we can make bgt support much more consistent. The final decision is still on David, I am happy to update both patches if needed. --- fs/btrfs/disk-io.c | 25 +++++++++++++------ fs/btrfs/free-space-tree.c | 50 +++++++++++++++++++++++++++++++++++++- fs/btrfs/free-space-tree.h | 3 ++- fs/btrfs/super.c | 3 +-- 4 files changed, 70 insertions(+), 11 deletions(-)