Commit 3822743d authored by Helen Koike's avatar Helen Koike Committed by Theodore Ts'o
Browse files

ext4: reject mount if bigalloc with s_first_data_block != 0 



bigalloc with s_first_data_block != 0 is not supported, reject mounting
it.

Signed-off-by: default avatarHelen Koike <koike@igalia.com>
Suggested-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reported-by: default avatar <syzbot+b73703b873a33d8eb8f6@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=b73703b873a33d8eb8f6
Link: https://patch.msgid.link/20260317142325.135074-1-koike@igalia.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
parent 9e1b1432

fs/ext4/super.c

+7 −0
Original line number Diff line number Diff line
@@ -3633,6 +3633,13 @@ int ext4_feature_set_ok(struct super_block *sb, int readonly) 
			 "extents feature\n");

		return 0;

	}

	if (ext4_has_feature_bigalloc(sb) &&

	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {

		ext4_msg(sb, KERN_WARNING,

			 "bad geometry: bigalloc file system with non-zero "

			 "first_data_block\n");

		return 0;

	}



#if !IS_ENABLED(CONFIG_QUOTA) || !IS_ENABLED(CONFIG_QFMT_V2)

	if (!readonly && (ext4_has_feature_quota(sb) ||