Ping?
On 2019/10/17 下午3:36, Qu Wenruo wrote:
> [BUG]
> When a subvolume is created, we automatically create a level 0 qgroup
> for it, but don't remove it when the subvolume is dropped.
>
> Although it's not a big deal, it can easily pollute the output of
> "btrfs qgroup show" and make it pretty annoying.
>
> [FIX]
> For btrfs_drop_snapshot(), if it's a valid subvolume (not a reloc tree)
> and qgroup is enabled, we do the following work to remove the qgroup:
> - Commit transaction
> This is to ensure that the qgroup numbers of that subvolume is updated
> properly (all number of that subvolume should be 0).
>
> - Start a new transaction for later operation
>
> - Call btrfs_remove_qgroup()
>
> So that qgroup can be automatically removed when the subvolume get fully
> dropped.
>
> Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
> ---
> fs/btrfs/extent-tree.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
> index 49cb26fa7c63..5e8569cad16d 100644
> --- a/fs/btrfs/extent-tree.c
> +++ b/fs/btrfs/extent-tree.c
> @@ -5182,6 +5182,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
> struct btrfs_root_item *root_item = &root->root_item;
> struct walk_control *wc;
> struct btrfs_key key;
> + u64 rootid = root->root_key.objectid;
> int err = 0;
> int ret;
> int level;
> @@ -5384,6 +5385,30 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
> }
> root_dropped = true;
> out_end_trans:
> + /* If qgroup is enabled, also try to remove the qgroup */
> + if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags) && root_dropped &&
> + is_fstree(rootid) && !for_reloc) {
> + /* Commit transaction so qgroup numbers get updated to all 0 */
> + ret = btrfs_commit_transaction(trans);
> + if (ret < 0) {
> + btrfs_end_transaction_throttle(trans);
> + err = ret;
> + goto out_free;
> + }
> + trans = btrfs_start_transaction(fs_info->quota_root, 1);
> + if (IS_ERR(trans)) {
> + err = PTR_ERR(trans);
> + goto out_free;
> + }
> +
> + /*
> + * Here we ignore the return value of btrfs_remove_qgroup(),
> + * as there is no critical error could happen.
> + * Error like EINVAL (quota disabled) or ENOENT (no such qgroup)
> + * are all safe to ignore.
> + */
> + btrfs_remove_qgroup(trans, rootid);
> + }
> btrfs_end_transaction_throttle(trans);
> out_free:
> kfree(wc);
>
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