Btrfs: specify a new ordered extent type for create_io_em

As 0 refers to an existing type BTRFS_ORDERED_IO_DONE, this specifies a
new type 'REGULAR' for regular IO.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -991,7 +991,7 @@ static noinline int cow_file_range(struct inode *inode,
 				  ins.offset, /* orig_block_len */
 				  ram_size, /* ram_bytes */
 				  BTRFS_COMPRESS_NONE, /* compress_type */
-				  0 /* type */);
+				  BTRFS_ORDERED_REGULAR /* type */);
 		if (IS_ERR(em))
 			goto out_reserve;
 		free_extent_map(em);
@@ -7506,7 +7506,7 @@ static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
 	ASSERT(type == BTRFS_ORDERED_PREALLOC ||
 	       type == BTRFS_ORDERED_COMPRESSED ||
 	       type == BTRFS_ORDERED_NOCOW ||
-	       type == 0);
+	       type == BTRFS_ORDERED_REGULAR);
 
 	em_tree = &BTRFS_I(inode)->extent_tree;
 	em = alloc_extent_map();
@@ -7523,9 +7523,9 @@ static struct extent_map *create_io_em(struct inode *inode, u64 start, u64 len,
 	em->ram_bytes = ram_bytes;
 	em->generation = -1;
 	set_bit(EXTENT_FLAG_PINNED, &em->flags);
-	if (type == BTRFS_ORDERED_PREALLOC)
+	if (type == BTRFS_ORDERED_PREALLOC) {
 		set_bit(EXTENT_FLAG_FILLING, &em->flags);
-	else if (type == BTRFS_ORDERED_COMPRESSED) {
+	} else if (type == BTRFS_ORDERED_COMPRESSED) {
 		set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
 		em->compress_type = compress_type;
 	}

fs/btrfs/ordered-data.h

@@ -75,6 +75,8 @@ struct btrfs_ordered_sum {
 				 * in the logging code. */
 #define BTRFS_ORDERED_PENDING 11 /* We are waiting for this ordered extent to
 				  * complete in the current transaction. */
+#define BTRFS_ORDERED_REGULAR 12 /* Regular IO for COW */
+
 struct btrfs_ordered_extent {
 	/* logical offset in the file */
 	u64 file_offset;