Re: [PATCH 2/2] btrfs-progs: mark static & remove unused from non-kernel code

[Stefan Behrens <sbehrens@giantdisaster.de>]

On Tue, 06 Aug 2013 22:49:32 -0500, Eric Sandeen wrote:
> On 8/6/13 8:05 PM, Eric Sandeen wrote:
>> Mark many functions as static, and remove any resulting dead code.
>>
>> Signed-off-by: Eric Sandeen <sandeen@redhat.com>
>> ---
> ...
> 
> Actually, what the heck was this (note, this patch was against kdave's integration tree):
> 
>> diff --git a/send-utils.c b/send-utils.c
>> index 874f8a5..3d562a4 100644
>> --- a/send-utils.c
>> +++ b/send-utils.c
>> @@ -255,15 +255,6 @@ static int btrfs_subvolid_resolve_sub(int fd, char *path, size_t *path_len,
>>  	return 0;
>>  }
>>  
>> -void subvol_uuid_search_add(struct subvol_uuid_search *s,
>> -			    struct subvol_info *si)
>> -{
>> -	if (si) {
>> -		free(si->path);
>> -		free(si);
>> -	}
>> -}
>> -
> 
> That code above came into being with "[PATCH v4 3/5] Btrfs-progs: use UUID tree for send/receive" -
> 
>  void subvol_uuid_search_add(struct subvol_uuid_search *s,
>  			    struct subvol_info *si)
>  {
> -	int cnt;
> -
> -	tree_insert(&s->root_id_subvols, si, subvol_search_by_root_id);
> -	tree_insert(&s->path_subvols, si, subvol_search_by_path);
> -
> -	cnt = count_bytes(si->uuid, BTRFS_UUID_SIZE, 0);
> -	if (cnt != BTRFS_UUID_SIZE)
> -		tree_insert(&s->local_subvols, si, subvol_search_by_uuid);
> -	cnt = count_bytes(si->received_uuid, BTRFS_UUID_SIZE, 0);
> -	if (cnt != BTRFS_UUID_SIZE)
> -		tree_insert(&s->received_subvols, si,
> -				subvol_search_by_received_uuid);
> +	if (si) {
> +		free(si->path);
> +		free(si);
> +	}
>  }
> 
> is that, um, really as intended, or did something get misapplied somewhere?

That was as intended. subvol_uuid_search_add() was not needed anymore
after the UUID tree patch. But it's part of the btrfs library interface
which I didn't want to break.

Before the UUID tree patch, the send/receive code was creating a
database (on the heap) of UUIDs, subvols and paths on each invocation.
The ..._add() function was part of that code. This database building
code was completely removed and replaced by code that uses the
tree-search ioctl (this was possible after the addition of the UUID tree
to the on-disk filesystem).

But subvol_uuid_search_add() is one of the exported btrfslib functions,
therefore I tried to stay compatible and to not break the interface.

To add a BTRFSLIB_VERSION define was proposed some time ago which is
updated with every interface change. I support this idea.

First thing I would like to change in the interface would be to add a
"btrfs_" prefix to all exported symbols. Unfortunately this is a 30k+
lines patch, I wrote a tiny sed script for it some time ago and this
huge patch was the result which I then throw away afterwards.