Re: [PATCH v1 4/8] btrfs: Add mountpoint checking during btrfs_copy_file_range

[Anna Schumaker <Anna.Schumaker@netapp.com>]

On 09/09/2015 05:18 AM, David Sterba wrote:
> On Fri, Sep 04, 2015 at 04:16:58PM -0400, Anna Schumaker wrote:
>> We need to verify that both the source and the destination files are
>> part of the same filesystem, otherwise we can't create a reflink.
>>
>> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
>> ---
>>  fs/btrfs/ioctl.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
>> index 62ae286..9c0c955 100644
>> --- a/fs/btrfs/ioctl.c
>> +++ b/fs/btrfs/ioctl.c
>> @@ -3856,6 +3856,10 @@ ssize_t btrfs_copy_file_range(struct file *file_in, loff_t pos_in,
>>  {
>>  	ssize_t ret;
>>  
>> +	if (inode_in->i_sb != inode_out->i_sb ||
>> +	    file_in->f_path.mnt != file_out->f_path.mnt)
>> +		return -EXDEV;
> 
> The same check exists in btrfs_clone_files (added in the previous
> patch), what's the reason to add it here again?

To be really, really sure that it's not a cross-device copy?  :)

In reality, it was an oversight and I'll drop the patch.  Thanks for letting me know!

Anna

> 
>> +
>>  	ret = btrfs_clone_files(file_out, file_in, pos_in, len, pos_out);