On Sun, May 21, 2017 at 6:39 PM, Qu Wenruo <[email protected]> wrote:
>
>
> At 05/20/2017 04:39 PM, Sargun Dhillon wrote:
>>
>> This patch is to prepare for following patches in this patchset. The
>> purpose is to make it so that we can prevent accidental removal of
>> qgroups that are actively in use.
>>
>> Signed-off-by: Sargun Dhillon <[email protected]>
>> ---
>> fs/btrfs/ioctl.c | 4 ++--
>> fs/btrfs/qgroup.c | 50
>> +++++++++++++++++++++++++++++++++++++++++++++++++-
>> fs/btrfs/qgroup.h | 3 ++-
>> 3 files changed, 53 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>> index b10d7bb..2b1a8c1 100644
>> --- a/fs/btrfs/ioctl.c
>> +++ b/fs/btrfs/ioctl.c
>> @@ -2554,7 +2554,7 @@ static noinline int btrfs_ioctl_snap_destroy(struct
>> file *file,
>> */
>> if (!btrfs_test_opt(fs_info, QGROUP_KEEP)) {
>> ret = btrfs_remove_qgroup(trans, fs_info,
>> - dest->root_key.objectid);
>> + dest->root_key.objectid, 0);
>> if (ret && ret != -ENOENT)
>> pr_info("Could not automatically delete qgroup:
>> %d\n", ret);
>> }
>> @@ -4974,7 +4974,7 @@ static long btrfs_ioctl_qgroup_create(struct file
>> *file, void __user *arg)
>> if (sa->create) {
>> ret = btrfs_create_qgroup(trans, fs_info, sa->qgroupid);
>> } else {
>> - ret = btrfs_remove_qgroup(trans, fs_info, sa->qgroupid);
>> + ret = btrfs_remove_qgroup(trans, fs_info, sa->qgroupid,
>> 0);
>> }
>> err = btrfs_end_transaction(trans);
>> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
>> index 588248b..a0699fd 100644
>> --- a/fs/btrfs/qgroup.c
>> +++ b/fs/btrfs/qgroup.c
>> @@ -1247,6 +1247,45 @@ int btrfs_del_qgroup_relation(struct
>> btrfs_trans_handle *trans,
>> return ret;
>> }
>> +/*
>> + * Meant to only operate on level-0 qroupid.
>> + *
>> + * It returns 1 if a matching subvolume is found; 0 if none is found.
>> + * < 0 if there is an error.
>> + */
>> +static int btrfs_subvolume_exists(struct btrfs_fs_info *fs_info, u64
>> qgroupid)
>> +{
>> + struct btrfs_path *path;
>> + struct btrfs_key key;
>> + int err, ret = 0;
>> +
>> + path = btrfs_alloc_path();
>> + if (!path)
>> + return -ENOMEM;
>> +
>> + key.objectid = qgroupid;
>> + key.type = BTRFS_ROOT_BACKREF_KEY;
>
>
> Fs root (subvolume id equals to 5) has no ROOT_BACKREF key.
> Such search would make fs tree always treated as not existed.
Is it okay to just explicitly exempt 5, or is there a better way to do
this search?
>
> Thanks,
> Qu
>
>> + key.offset = 0;
>> +
>> + err = btrfs_search_slot_for_read(fs_info->tree_root, &key, path,
>> 1, 0);
>> + if (err == 1)
>> + goto out;
>> +
>> + if (err) {
>> + ret = err;
>> + goto out;
>> + }
>> +
>> + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
>> + if (key.objectid != qgroupid || key.type !=
>> BTRFS_ROOT_BACKREF_KEY)
>> + goto out;
>> +
>> + ret = 1;
>> +out:
>> + btrfs_free_path(path);
>> + return ret;
>> +}
>> +
>> /* Must be called with qgroup_ioctl_lock held */
>> static int __btrfs_create_qgroup(struct btrfs_trans_handle *trans,
>> struct btrfs_fs_info *fs_info, u64
>> qgroupid)
>> @@ -1333,10 +1372,19 @@ static int __btrfs_remove_qgroup(struct
>> btrfs_trans_handle *trans,
>> }
>> int btrfs_remove_qgroup(struct btrfs_trans_handle *trans,
>> - struct btrfs_fs_info *fs_info, u64 qgroupid)
>> + struct btrfs_fs_info *fs_info, u64 qgroupid,
>> + int check_in_use)
>> {
>> int ret;
>> + if (check_in_use && btrfs_qgroup_level(qgroupid) == 0) {
>> + ret = btrfs_subvolume_exists(fs_info, qgroupid);
>> + if (ret < 0)
>> + return ret;
>> + if (ret)
>> + return -EBUSY;
>> + }
>> +
>> mutex_lock(&fs_info->qgroup_ioctl_lock);
>> ret = __btrfs_remove_qgroup(trans, fs_info, qgroupid);
>> mutex_unlock(&fs_info->qgroup_ioctl_lock);
>> diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
>> index fb6c7da..fc08bdb 100644
>> --- a/fs/btrfs/qgroup.h
>> +++ b/fs/btrfs/qgroup.h
>> @@ -127,7 +127,8 @@ int btrfs_del_qgroup_relation(struct
>> btrfs_trans_handle *trans,
>> int btrfs_create_qgroup(struct btrfs_trans_handle *trans,
>> struct btrfs_fs_info *fs_info, u64 qgroupid);
>> int btrfs_remove_qgroup(struct btrfs_trans_handle *trans,
>> - struct btrfs_fs_info *fs_info, u64 qgroupid);
>> + struct btrfs_fs_info *fs_info, u64 qgroupid,
>> + int check_in_use);
>> int btrfs_limit_qgroup(struct btrfs_trans_handle *trans,
>> struct btrfs_fs_info *fs_info, u64 qgroupid,
>> struct btrfs_qgroup_limit *limit);
>>
>
>
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