On 10/02/2020 16:09, David Sterba wrote:
> On Mon, Feb 10, 2020 at 05:02:01PM +0800, Qu Wenruo wrote:
>> Since commit ecd4bb607f35 ("btrfs-progs: docs: enhance btrfs-filesystem
>> manual page"), the man page of `btrfs filesystem` shows `sync`
>> subcommand will wait for all existing orphan subvolumes to be dropped.
>
> But this is not what the docs say, nor what the ioctl claims to do.
>
> 'trigger cleaning of deleted subvolumes' means that it just starts the
> process in some way (eg. by waking up the cleaner kthread that does the
> actual cleaning).
>
> For waiting on the subvolumes there's 'btrfs subvol sync' and that works
> as expected.
I agree. The original wording may be unclear (particularly so for users
who may have limited English and be confused by the use of "trigger"),
but it does seem to be different from sync(1) and the proposed change is
worse.
How about:
Force a sync of the filesystem at 'path', similar to the `sync`(1)
command. In addition, it starts cleaning of deleted subvolumes. To wait
for subvolume deletion to complete use the `btrfs subvolume sync` command.
SEE ALSO
btrfs-subvolume(8)
