btrfs: do not return errors from raid56_parity_recover

Always consume the bio and call the end_io handler on error instead of
returning an error and letting the caller handle it.  This matches what
the block layer submission does and avoids any confusion on who
needs to handle errors.

Also use the proper bool type for the generic_io argument.
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Tested-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NQu Wenruo <wqu@suse.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/raid56.c

@@ -2199,12 +2199,11 @@ static int __raid56_parity_recover(struct btrfs_raid_bio *rbio)
  * so we assume the bio they send down corresponds to a failed part
  * of the drive.
  */
-int raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
-			  int mirror_num, int generic_io)
+void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
+			   int mirror_num, bool generic_io)
 {
 	struct btrfs_fs_info *fs_info = bioc->fs_info;
 	struct btrfs_raid_bio *rbio;
-	int ret;
 
 	if (generic_io) {
 		ASSERT(bioc->mirror_num == mirror_num);
@@ -2213,9 +2212,8 @@ int raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
 
 	rbio = alloc_rbio(fs_info, bioc);
 	if (IS_ERR(rbio)) {
-		if (generic_io)
-			btrfs_put_bioc(bioc);
-		return PTR_ERR(rbio);
+		bio->bi_status = errno_to_blk_status(PTR_ERR(rbio));
+		goto out_end_bio;
 	}
 
 	rbio->operation = BTRFS_RBIO_READ_REBUILD;
@@ -2227,10 +2225,9 @@ int raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
 "%s could not find the bad stripe in raid56 so that we cannot recover any more (bio has logical %llu len %llu, bioc has map_type %llu)",
 			   __func__, bio->bi_iter.bi_sector << 9,
 			   (u64)bio->bi_iter.bi_size, bioc->map_type);
-		if (generic_io)
-			btrfs_put_bioc(bioc);
 		kfree(rbio);
-		return -EIO;
+		bio->bi_status = BLK_STS_IOERR;
+		goto out_end_bio;
 	}
 
 	if (generic_io) {
@@ -2257,24 +2254,20 @@ int raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
 			rbio->failb--;
 	}
 
-	ret = lock_stripe_add(rbio);
+	if (lock_stripe_add(rbio))
+		return;
 
 	/*
-	 * __raid56_parity_recover will end the bio with
-	 * any errors it hits.  We don't want to return
-	 * its error value up the stack because our caller
-	 * will end up calling bio_endio with any nonzero
-	 * return
+	 * This adds our rbio to the list of rbios that will be handled after
+	 * the current lock owner is done.
 	 */
-	if (ret == 0)
-		__raid56_parity_recover(rbio);
-	/*
-	 * our rbio has been added to the list of
-	 * rbios that will be handled after the
-	 * currently lock owner is done
-	 */
-	return 0;
+	__raid56_parity_recover(rbio);
+	return;
 
+out_end_bio:
+	if (generic_io)
+		btrfs_put_bioc(bioc);
+	bio_endio(bio);
 }
 
 static void rmw_work(struct work_struct *work)

fs/btrfs/raid56.h

@@ -165,8 +165,8 @@ static inline int nr_data_stripes(const struct map_lookup *map)
 
 struct btrfs_device;
 
-int raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
-			  int mirror_num, int generic_io);
+void raid56_parity_recover(struct bio *bio, struct btrfs_io_context *bioc,
+			   int mirror_num, bool generic_io);
 void raid56_parity_write(struct bio *bio, struct btrfs_io_context *bioc);
 
 void raid56_add_scrub_pages(struct btrfs_raid_bio *rbio, struct page *page,

fs/btrfs/scrub.c

@@ -1376,18 +1376,12 @@ static int scrub_submit_raid56_bio_wait(struct btrfs_fs_info *fs_info,
 					struct scrub_sector *sector)
 {
 	DECLARE_COMPLETION_ONSTACK(done);
-	int ret;
-	int mirror_num;
 
 	bio->bi_iter.bi_sector = sector->logical >> 9;
 	bio->bi_private = &done;
 	bio->bi_end_io = scrub_bio_wait_endio;
-
-	mirror_num = sector->sblock->sectors[0]->mirror_num;
-	ret = raid56_parity_recover(bio, sector->recover->bioc,
-				    mirror_num, 0);
-	if (ret)
-		return ret;
+	raid56_parity_recover(bio, sector->recover->bioc,
+			      sector->sblock->sectors[0]->mirror_num, false);
 
 	wait_for_completion_io(&done);
 	return blk_status_to_errno(bio->bi_status);

fs/btrfs/volumes.c

@@ -6764,7 +6764,7 @@ void btrfs_submit_bio(struct btrfs_fs_info *fs_info, struct bio *bio, int mirror
 		if (btrfs_op(bio) == BTRFS_MAP_WRITE)
 			raid56_parity_write(bio, bioc);
 		else
-			ret = raid56_parity_recover(bio, bioc, mirror_num, 1);
+			raid56_parity_recover(bio, bioc, mirror_num, true);
 		goto out_dec;
 	}