Btrfs: check return value of bio_alloc() properly

bio_alloc() has the possibility of returning NULL.
So, it is necessary to check the return value.

Signed-off-by: Tsutomu Itoh <[e-mail]>
Signed-off-by: Chris Mason <[e-mail]>

fs/btrfs/compression.c

···
 			bio_put(bio);
 
 			bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
+			BUG_ON(!bio);
 			bio->bi_private = cb;
 			bio->bi_end_io = end_compressed_bio_write;
 			bio_add_page(bio, page, PAGE_CACHE_SIZE, 0);
···
 
 			comp_bio = compressed_bio_alloc(bdev, cur_disk_byte,
 							GFP_NOFS);
+			BUG_ON(!comp_bio);
 			comp_bio->bi_private = cb;
 			comp_bio->bi_end_io = end_compressed_bio_read;
 

fs/btrfs/extent_io.c

···
 	}
 
 	bio = bio_alloc(GFP_NOFS, 1);
+	if (!bio) {
+		free_io_failure(inode, failrec, 0);
+		return -EIO;
+	}
 	bio->bi_private = state;
 	bio->bi_end_io = failed_bio->bi_end_io;
 	bio->bi_sector = failrec->logical >> 9;

fs/btrfs/scrub.c

···
 
 		BUG_ON(!page->page);
 		bio = bio_alloc(GFP_NOFS, 1);
+		if (!bio)
+			return -EIO;
 		bio->bi_bdev = page->bdev;
 		bio->bi_sector = page->physical >> 9;
 		bio->bi_end_io = scrub_complete_bio_end_io;
···
 		DECLARE_COMPLETION_ONSTACK(complete);
 
 		bio = bio_alloc(GFP_NOFS, 1);
+		if (!bio)
+			return -EIO;
 		bio->bi_bdev = page_bad->bdev;
 		bio->bi_sector = page_bad->physical >> 9;
 		bio->bi_end_io = scrub_complete_bio_end_io;