ext4: set the type of max_zeroout to unsigned int to avoid overflow

The max_zeroout is of type int and the s_extent_max_zeroout_kb is of
type uint, and the s_extent_max_zeroout_kb can be freely modified via
the sysfs interface. When the block size is 1024, max_zeroout may
overflow, so declare it as unsigned int to avoid overflow.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240319113325.3110393-9-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

Author: LiBaokun96

fs/ext4/extents.c

@@ -3402,9 +3402,10 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 	struct ext4_extent *ex, *abut_ex;
 	ext4_lblk_t ee_block, eof_block;
 	unsigned int ee_len, depth, map_len = map->m_len;
-	int allocated = 0, max_zeroout = 0;
 	int err = 0;
 	int split_flag = EXT4_EXT_DATA_VALID2;
+	int allocated = 0;
+	unsigned int max_zeroout = 0;
 
 	ext_debug(inode, "logical block %llu, max_blocks %u\n",
 		  (unsigned long long)map->m_lblk, map_len);