btrfs: raid56: transfer the bio counter reference to the raid submission helpers

Transfer the bio counter reference acquired by btrfs_submit_bio to
raid56_parity_write and raid56_parity_recovery together with the bio
that the reference was acquired for instead of acquiring another
reference in those helpers and dropping the original one in
btrfs_submit_bio.
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Tested-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/raid56.c

@@ -1815,12 +1815,11 @@ void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc)
 	if (IS_ERR(rbio)) {
 		btrfs_put_bioc(bioc);
 		ret = PTR_ERR(rbio);
-		goto out;
+		goto out_dec_counter;
 	}
 	rbio->operation = BTRFS_RBIO_WRITE;
 	rbio_add_bio(rbio, bio);
 
-	btrfs_bio_counter_inc_noblocked(fs_info);
 	rbio->generic_bio_cnt = 1;
 
 	/*
@@ -1852,7 +1851,6 @@ void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc)
 
 out_dec_counter:
 	btrfs_bio_counter_dec(fs_info);
-out:
 	bio->bi_status = errno_to_blk_status(ret);
 	bio_endio(bio);
 }
@@ -2208,6 +2206,8 @@ void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
 	if (generic_io) {
 		ASSERT(bioc->mirror_num == mirror_num);
 		btrfs_bio(bio)->mirror_num = mirror_num;
+	} else {
+		btrfs_get_bioc(bioc);
 	}
 
 	rbio = alloc_rbio(fs_info, bioc);
@@ -2230,12 +2230,8 @@ void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
 		goto out_end_bio;
 	}
 
-	if (generic_io) {
-		btrfs_bio_counter_inc_noblocked(fs_info);
+	if (generic_io)
 		rbio->generic_bio_cnt = 1;
-	} else {
-		btrfs_get_bioc(bioc);
-	}
 
 	/*
 	 * Loop retry:
@@ -2265,8 +2261,8 @@ void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
 	return;
 
 out_end_bio:
-	if (generic_io)
-		btrfs_put_bioc(bioc);
+	btrfs_bio_counter_dec(fs_info);
+	btrfs_put_bioc(bioc);
 	bio_endio(bio);
 }
 

fs/btrfs/volumes.c

@@ -6750,8 +6750,12 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror
 	btrfs_bio_counter_inc_blocked(fs_info);
 	ret = __btrfs_map_block(fs_info, btrfs_op(bio), logical,
 				&map_length, &bioc, mirror_num, 1);
-	if (ret)
-		goto out_dec;
+	if (ret) {
+		btrfs_bio_counter_dec(fs_info);
+		bio->bi_status = errno_to_blk_status(ret);
+		bio_endio(bio);
+		return;
+	}
 
 	total_devs = bioc->num_stripes;
 	bioc->orig_bio = bio;
@@ -6765,7 +6769,7 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror
 			raid56_parity_write(bio, bioc);
 		else
 			raid56_parity_recover(bio, bioc, mirror_num, true);
-		goto out_dec;
+		return;
 	}
 
 	if (map_length < length) {
@@ -6780,12 +6784,7 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror
 
 		submit_stripe_bio(bioc, bio, dev_nr, should_clone);
 	}
-out_dec:
 	btrfs_bio_counter_dec(fs_info);
-	if (ret) {
-		bio->bi_status = errno_to_blk_status(ret);
-		bio_endio(bio);
-	}
 }
 
 static bool dev_args_match_fs_devices(const struct btrfs_dev_lookup_args *args,