btrfs-progs: Refactor sectorsize users in file.c

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>

Author: Qu Wenruo

file.c

@@ -193,10 +193,10 @@ int btrfs_read_file(struct btrfs_root *root, u64 ino, u64 start, int len,
 	int read = 0;
 	int ret;
 
-	if (!IS_ALIGNED(start, root->sectorsize) ||
-	    !IS_ALIGNED(len, root->sectorsize)) {
+	if (!IS_ALIGNED(start, root->fs_info->sectorsize) ||
+	    !IS_ALIGNED(len, root->fs_info->sectorsize)) {
 		warning("@start and @len must be aligned to %u for function %s",
-			root->sectorsize, __func__);
+			root->fs_info->sectorsize, __func__);
 		return -EINVAL;
 	}
 
@@ -260,7 +260,7 @@ int btrfs_read_file(struct btrfs_root *root, u64 ino, u64 start, int len,
 				goto next;
 			read_extent_buffer(leaf, dest,
 				btrfs_file_extent_inline_start(fi), extent_len);
-			read += round_up(extent_len, root->sectorsize);
+			read += round_up(extent_len, root->fs_info->sectorsize);
 			break;
 		}
 
@@ -319,7 +319,7 @@ int btrfs_read_file(struct btrfs_root *root, u64 ino, u64 start, int len,
 		ii = btrfs_item_ptr(path.nodes[0], path.slots[0],
 				    struct btrfs_inode_item);
 		isize = round_up(btrfs_inode_size(path.nodes[0], ii),
-				 root->sectorsize);
+				 root->fs_info->sectorsize);
 		read = min_t(u64, isize - start, len);
 	}
 out: