btrfs: Use less confusing condition for uptodate parameter to btrfs_writepage_endio_finish_ordered

The uptodate parameter of btrfs_writepage_endio_finish_ordered is used
to signal whether an error has occured while writing the given page.
0 signals an error, which is propagated to callees and 1 signifies
success. In end_compressed_bio_write the ->bi_status is checked and
based on it either BLK_STS_OK (0) or BLK_STS_NOTSUPP (1) are used. While
from functional point of view this is ok it's a for the poor reader of
the code, since the block layer values are conflated with the semantics
of the parameter.

Just use plain 0 or 1. No functional changes.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/compression.c

@@ -251,7 +251,7 @@ static void end_compressed_bio_write(struct bio *bio)
 	cb->compressed_pages[0]->mapping = cb->inode->i_mapping;
 	btrfs_writepage_endio_finish_ordered(cb->compressed_pages[0],
 			cb->start, cb->start + cb->len - 1,
-			bio->bi_status ? BLK_STS_OK : BLK_STS_NOTSUPP);
+			bio->bi_status == BLK_STS_OK);
 	cb->compressed_pages[0]->mapping = NULL;
 
 	end_compressed_writeback(inode, cb);