btrfs-progs: Fix a clang dead-judgement warning in disk-io.c.

When compiled with clang, the following warning is outputted.

disk-io.c:1017:15: warning: comparison of unsigned expression < 0 is
always false [-Wtautological-compare]
        if (dev_size < 0)
            ~~~~~~~~ ^ ~
1 warning generated.

This is because dev_size is defined as unsigned type, but lseek() will
return singed valued.
So the judgement will always to false.

Use temporary off_t return value to solve it.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.cz>

0 files changed, 0 insertions, 0 deletions