On 2018/08/03 16:15, Lu Fengqi wrote:
> On Fri, Aug 03, 2018 at 03:21:12PM +0900, Misono Tomohiro wrote:
>> When qgroup is on, subvolume deletion does not remove qgroup item
>> of the subvolume (qgroup info, limits, relation) from quota tree and
>> they needs to get removed manually by "btrfs qgroup destroy".
>>
>> Since level 0 qgroup cannot be used/inherited by any other subvolume,
>> let's remove them automatically when subvolume is deleted
>> (to be precise, when the subvolume root is dropped).
>>
>> Signed-off-by: Misono Tomohiro <misono.tomoh...@jp.fujitsu.com>
>
> Looks good to me.
>
> Reviewed-by: Lu Fengqi <lufq.f...@cn.fujitsu.com>
Thanks for the review.
>
> There is an off-topic question below.
>
>> ---
>> Note that btrfs/057 fails, but it is the problem of testcase.
>> I will update it too.
>>
>> v1 -> v2:
>> Move call of btrfs_remove_qgroup() from btrfs_delete_subvolume()
>> to btrfs_snapshot_destroy() so that it will be called after the
>> subvolume root is really dropped
>>
>> fs/btrfs/extent-tree.c | 16 ++++++++++++----
>> 1 file changed, 12 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
>> index 9e7b237b9547..b56dea8c8b9f 100644
>> --- a/fs/btrfs/extent-tree.c
>> +++ b/fs/btrfs/extent-tree.c
>> @@ -8871,12 +8871,13 @@ 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 objectid = root->objectid;
>> int err = 0;
>> int ret;
>> int level;
>> bool root_dropped = false;
>>
>> - btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
>> + btrfs_debug(fs_info, "Drop subvolume %llu", objectid);
>>
>> path = btrfs_alloc_path();
>> if (!path) {
>> @@ -9030,7 +9031,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
>> goto out_end_trans;
>> }
>>
>> - if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
>> + if (objectid != BTRFS_TREE_RELOC_OBJECTID) {
>
> Here use root->objectid instead of root->root_key.objectid. If I recall
> correctly, the root->objectid and root->root_key.objectid are set to the
> identical value. I just wonder if there is any difference between the two
> "objectid"s after the btrfs_root was created?
in __setup_root(root, fs_info, objectid):
<snip>
root->objectid = objectid;
<snip>
root->root_key.objectid = objectid;
<snip>
and I don't see any update of objectid from "grep -r "root_key.objectid ="",
I think it the same too (and fstests is ok), but any comment from
those who more familiar with code is helpful.
thanks,
Misono
>
> --
> Thanks,
> Lu
>
>> ret = btrfs_find_root(tree_root, &root->root_key, path,
>> NULL, NULL);
>> if (ret < 0) {
>> @@ -9043,8 +9044,7 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
>> *
>> * The most common failure here is just -ENOENT.
>> */
>> - btrfs_del_orphan_item(trans, tree_root,
>> - root->root_key.objectid);
>> + btrfs_del_orphan_item(trans, tree_root, objectid);
>> }
>> }
>>
>> @@ -9056,6 +9056,14 @@ int btrfs_drop_snapshot(struct btrfs_root *root,
>> btrfs_put_fs_root(root);
>> }
>> root_dropped = true;
>> +
>> + /* Remove level-0 qgroup items since no other subvolume can use them */
>> + ret = btrfs_remove_qgroup(trans, objectid);
>> + if (ret && ret != -EINVAL && ret != -ENOENT) {
>> + btrfs_abort_transaction(trans, ret);
>> + err = ret;
>> + }
>> +
>> out_end_trans:
>> btrfs_end_transaction_throttle(trans);
>> out_free:
>> --
>> 2.14.4
>>
>>
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>>
>
>
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