mke2fs: make s_inodes_per_group >= 8 in ext2fs_initialize

current mkfs.ext4 fails if we tried with the following parameters:

	mkfs.ext4  -m 0 -N 16 -O ^has_journal,^resize_inode,^uninit_bg,extent,meta_bg -b 1024 /dev/sdb3

It will cause segfault, but it is caused by another issue.  See my
patch "mke2fs: Avoid segmentation fault in
ext2fs_alloc_generic_bmap". And with that patch, the mkfs.ext4 will
fail with the error: /dev/sdb3: Memory allocation failed while setting
up superblock

The reason is that in ext2fs_initialize, we align s_inodes_per_group
to 8, but fails to consider the case that s_inodes_per_group < 8.
So make at least 8 inodes for s_inodes_per_group.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/lib/ext2fs/initialize.c b/lib/ext2fs/initialize.c
index e1f229b..4706773 100644 (file)
--- a/lib/ext2fs/initialize.c
+++ b/lib/ext2fs/initialize.c
@@ -282,6 +282,8 @@ ipg_retry:
         * multiple of 8.  This is needed to simplify the bitmap
         * splicing code.
         */
+       if (super->s_inodes_per_group < 8)
+               super->s_inodes_per_group = 8;
        super->s_inodes_per_group &= ~7;
        fs->inode_blocks_per_group = (((super->s_inodes_per_group *
                                        EXT2_INODE_SIZE(super)) +