block: rename bio bi_rw to bi_opf

Since commit 63a4cc24867d, bio->bi_rw contains flags in the lower
portion and the op code in the higher portions. This means that
old code that relies on manually setting bi_rw is most likely
going to be broken. Instead of letting that brokeness linger,
rename the member, to force old and out-of-tree code to break
at compile time instead of at runtime.

No intended functional changes in this commit.

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 5d5cae0..6678947 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -2945,7 +2945,7 @@
 			printk(KERN_INFO
 			       "submit_bio(rw=%d,0x%x, bi_vcnt=%u,"
 			       " bi_sector=%llu (bytenr %llu), bi_bdev=%p)\n",
-			       bio_op(bio), bio->bi_rw, bio->bi_vcnt,
+			       bio_op(bio), bio->bi_opf, bio->bi_vcnt,
 			       (unsigned long long)bio->bi_iter.bi_sector,
 			       dev_bytenr, bio->bi_bdev);
 
@@ -2976,18 +2976,18 @@
 		btrfsic_process_written_block(dev_state, dev_bytenr,
 					      mapped_datav, bio->bi_vcnt,
 					      bio, &bio_is_patched,
-					      NULL, bio->bi_rw);
+					      NULL, bio->bi_opf);
 		while (i > 0) {
 			i--;
 			kunmap(bio->bi_io_vec[i].bv_page);
 		}
 		kfree(mapped_datav);
-	} else if (NULL != dev_state && (bio->bi_rw & REQ_PREFLUSH)) {
+	} else if (NULL != dev_state && (bio->bi_opf & REQ_PREFLUSH)) {
 		if (dev_state->state->print_mask &
 		    BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH)
 			printk(KERN_INFO
 			       "submit_bio(rw=%d,0x%x FLUSH, bdev=%p)\n",
-			       bio_op(bio), bio->bi_rw, bio->bi_bdev);
+			       bio_op(bio), bio->bi_opf, bio->bi_bdev);
 		if (!dev_state->dummy_block_for_bio_bh_flush.is_iodone) {
 			if ((dev_state->state->print_mask &
 			     (BTRFSIC_PRINT_MASK_SUBMIT_BIO_BH |
@@ -3005,7 +3005,7 @@
 			block->never_written = 0;
 			block->iodone_w_error = 0;
 			block->flush_gen = dev_state->last_flush_gen + 1;
-			block->submit_bio_bh_rw = bio->bi_rw;
+			block->submit_bio_bh_rw = bio->bi_opf;
 			block->orig_bio_bh_private = bio->bi_private;
 			block->orig_bio_bh_end_io.bio = bio->bi_end_io;
 			block->next_in_same_bio = NULL;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 87dad55..59febfb 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -870,7 +870,7 @@
 
 	atomic_inc(&fs_info->nr_async_submits);
 
-	if (bio->bi_rw & REQ_SYNC)
+	if (bio->bi_opf & REQ_SYNC)
 		btrfs_set_work_high_priority(&async->work);
 
 	btrfs_queue_work(fs_info->workers, &async->work);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index b0f421f3..2f59759 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8209,7 +8209,7 @@
 	if (err)
 		btrfs_warn(BTRFS_I(dip->inode)->root->fs_info,
 			   "direct IO failed ino %llu rw %d,%u sector %#Lx len %u err no %d",
-			   btrfs_ino(dip->inode), bio_op(bio), bio->bi_rw,
+			   btrfs_ino(dip->inode), bio_op(bio), bio->bi_opf,
 			   (unsigned long long)bio->bi_iter.bi_sector,
 			   bio->bi_iter.bi_size, err);
 
@@ -8373,7 +8373,7 @@
 	if (!bio)
 		return -ENOMEM;
 
-	bio_set_op_attrs(bio, bio_op(orig_bio), orig_bio->bi_rw);
+	bio_set_op_attrs(bio, bio_op(orig_bio), orig_bio->bi_opf);
 	bio->bi_private = dip;
 	bio->bi_end_io = btrfs_end_dio_bio;
 	btrfs_io_bio(bio)->logical = file_offset;
@@ -8411,7 +8411,7 @@
 						  start_sector, GFP_NOFS);
 			if (!bio)
 				goto out_err;
-			bio_set_op_attrs(bio, bio_op(orig_bio), orig_bio->bi_rw);
+			bio_set_op_attrs(bio, bio_op(orig_bio), orig_bio->bi_opf);
 			bio->bi_private = dip;
 			bio->bi_end_io = btrfs_end_dio_bio;
 			btrfs_io_bio(bio)->logical = file_offset;
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index bb0addc..51f1255 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -6012,7 +6012,7 @@
 				else
 					btrfs_dev_stat_inc(dev,
 						BTRFS_DEV_STAT_READ_ERRS);
-				if ((bio->bi_rw & WRITE_FLUSH) == WRITE_FLUSH)
+				if ((bio->bi_opf & WRITE_FLUSH) == WRITE_FLUSH)
 					btrfs_dev_stat_inc(dev,
 						BTRFS_DEV_STAT_FLUSH_ERRS);
 				btrfs_dev_stat_print_on_error(dev);
@@ -6089,7 +6089,7 @@
 	bio->bi_next = NULL;
 
 	spin_lock(&device->io_lock);
-	if (bio->bi_rw & REQ_SYNC)
+	if (bio->bi_opf & REQ_SYNC)
 		pending_bios = &device->pending_sync_bios;
 	else
 		pending_bios = &device->pending_bios;
@@ -6127,7 +6127,7 @@
 		rcu_read_lock();
 		name = rcu_dereference(dev->name);
 		pr_debug("btrfs_map_bio: rw %d 0x%x, sector=%llu, dev=%lu "
-			 "(%s id %llu), size=%u\n", bio_op(bio), bio->bi_rw,
+			 "(%s id %llu), size=%u\n", bio_op(bio), bio->bi_opf,
 			 (u64)bio->bi_iter.bi_sector, (u_long)dev->bdev->bd_dev,
 			 name->str, dev->devid, bio->bi_iter.bi_size);
 		rcu_read_unlock();