btrfs: fix range_end calculation in extent_write_locked_range

The range_end field in struct writeback_control is inclusive, just like
the end parameter passed to extent_write_locked_range.  Not doing this
could cause extra writeout, which is harmless but suboptimal.

Fixes: 771ed689 ("Btrfs: Optimize compressed writeback and reads")
CC: stable@vger.kernel.org # 5.9+
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent_io.c

@@ -2310,7 +2310,7 @@ int extent_write_locked_range(struct inode *inode, u64 start, u64 end)
 	struct writeback_control wbc_writepages = {
 		.sync_mode	= WB_SYNC_ALL,
 		.range_start	= start,
-		.range_end	= end + 1,
+		.range_end	= end,
 		.no_cgroup_owner = 1,
 	};
 	struct btrfs_bio_ctrl bio_ctrl = {