ext2: fix block range in ext2_data_block_valid()

For block validity we should check the block range
from start_block to start_block + count - 1, so fix
the range in ext2_data_block_valid() and also modify
the count argument properly in calling place.

Signed-off-by: Chengguang Xu <cgxu519@zoho.com.cn>
Link: https://lore.kernel.org/r/20190723112155.20329-1-cgxu519@zoho.com.cn
Signed-off-by: Jan Kara <jack@suse.cz>

fs/ext2/xattr.c

@@ -794,7 +794,7 @@ ext2_xattr_delete_inode(struct inode *inode)
 	if (!EXT2_I(inode)->i_file_acl)
 		goto cleanup;
 
-	if (!ext2_data_block_valid(sbi, EXT2_I(inode)->i_file_acl, 0)) {
+	if (!ext2_data_block_valid(sbi, EXT2_I(inode)->i_file_acl, 1)) {
 		ext2_error(inode->i_sb, "ext2_xattr_delete_inode",
 			"inode %ld: xattr block %d is out of data blocks range",
 			inode->i_ino, EXT2_I(inode)->i_file_acl);