Re: [PATCH] btrfs: Add comments on locking of several device-related fields

[Nikolay Borisov <nborisov@suse.com>]

On 9.05.19 г. 16:55 ч., David Sterba wrote:
> On Tue, May 07, 2019 at 05:24:28PM +0300, Nikolay Borisov wrote:
>> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
>> ---
>>  fs/btrfs/volumes.h | 11 ++++++++---
>>  1 file changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
>> index 3b97e8092ba7..514799362244 100644
>> --- a/fs/btrfs/volumes.h
>> +++ b/fs/btrfs/volumes.h
>> @@ -52,8 +52,8 @@ struct btrfs_io_geometry {
>>  #define BTRFS_DEV_STATE_FLUSH_SENT	(4)
>>  
>>  struct btrfs_device {
>> -	struct list_head dev_list;
>> -	struct list_head dev_alloc_list;
>> +	struct list_head dev_list; /* device_list_mutex */
>> +	struct list_head dev_alloc_list; /* chunk mutex */
>>  	struct list_head post_commit_list; /* chunk mutex */
> 
> Please update the documentation in the comment 'Device locking' in
> volumes.c
> 

Right the only thing that is missing from the Device Locking comment is
the mention of post_commit_list. However, dev_list and dev_alloc_list
are essentially "the other side" of btrfs_fs_devices::alloc_list  hence
I've added them as inline comments. I think it makes more sense to those
small comments next to the variables at least as a remainder.