ext4: unify the type of flexbg_size to unsigned int

[ Upstream commit 658a52344fb139f9531e7543a6e0015b630feb38 ]

The maximum value of flexbg_size is 2^31, but the maximum value of int
is (2^31 - 1), so overflow may occur when the type of flexbg_size is
declared as int.

For example, when uninit_mask is initialized in ext4_alloc_group_tables(),
if flexbg_size == 2^31, the initialized uninit_mask is incorrect, and this
may causes set_flexbg_block_bitmap() to trigger a BUG_ON().

Therefore, the flexbg_size type is declared as unsigned int to avoid
overflow and memory waste.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20231023013057.2117948-2-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 6673811..f3a9b97 100644 (file)
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -241,7 +241,7 @@ struct ext4_new_flex_group_data {
  *
  * Returns NULL on failure otherwise address of the allocated structure.
  */
-static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned long flexbg_size)
+static struct ext4_new_flex_group_data *alloc_flex_gd(unsigned int flexbg_size)
 {
        struct ext4_new_flex_group_data *flex_gd;
 
@@ -296,7 +296,7 @@ static void free_flex_gd(struct ext4_new_flex_group_data *flex_gd)
  */
 static int ext4_alloc_group_tables(struct super_block *sb,
                                struct ext4_new_flex_group_data *flex_gd,
-                               int flexbg_size)
+                               unsigned int flexbg_size)
 {
        struct ext4_new_group_data *group_data = flex_gd->groups;
        ext4_fsblk_t start_blk;
@@ -397,12 +397,12 @@ next_group:
                group = group_data[0].group;
 
                printk(KERN_DEBUG "EXT4-fs: adding a flex group with "
-                      "%d groups, flexbg size is %d:\n", flex_gd->count,
+                      "%u groups, flexbg size is %u:\n", flex_gd->count,
                       flexbg_size);
 
                for (i = 0; i < flex_gd->count; i++) {
                        ext4_debug(
-                              "adding %s group %u: %u blocks (%d free, %d mdata blocks)\n",
+                              "adding %s group %u: %u blocks (%u free, %u mdata blocks)\n",
                               ext4_bg_has_super(sb, group + i) ? "normal" :
                               "no-super", group + i,
                               group_data[i].blocks_count,
@@ -1623,7 +1623,7 @@ exit:
 static int ext4_setup_next_flex_gd(struct super_block *sb,
                                    struct ext4_new_flex_group_data *flex_gd,
                                    ext4_fsblk_t n_blocks_count,
-                                   unsigned long flexbg_size)
+                                   unsigned int flexbg_size)
 {
        struct ext4_sb_info *sbi = EXT4_SB(sb);
        struct ext4_super_block *es = sbi->s_es;
@@ -2007,8 +2007,9 @@ int ext4_resize_fs(struct super_block *sb, ext4_fsblk_t n_blocks_count)
        ext4_fsblk_t o_blocks_count;
        ext4_fsblk_t n_blocks_count_retry = 0;
        unsigned long last_update_time = 0;
-       int err = 0, flexbg_size = 1 << sbi->s_log_groups_per_flex;
+       int err = 0;
        int meta_bg;
+       unsigned int flexbg_size = ext4_flex_bg_size(sbi);
 
        /* See if the device is actually as big as what was requested */
        bh = ext4_sb_bread(sb, n_blocks_count - 1, 0);