I'm using v1.43-WIP-2012-09-22-10-g41bf599, last commit Oct. 14. I'm trying to create a file system with 64bit support and specify a maximum resize limit of 64 TiB = 2^34 blocks = 17179869184. (gdb) run -n -t ext4 -O 64bit -E resize=4294967296 /dev/md1 Starting program: /root/e2fsprogs/misc/mke2fs -n -t ext4 -O 64bit -E resize=4294967295 /dev/md1 [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1". mke2fs 1.43-WIP (22-Sep-2012) Program received signal SIGFPE, Arithmetic exception. 0x0000000000405f5a in parse_extended_opts (opts=<optimized out>, param=0x64e200) at mke2fs.c:800 800 gdpb = EXT2_DESC_PER_BLOCK(param); The issue is that #define EXT2_DESC_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / EXT2_DESC_SIZE(s)) #define EXT2_DESC_SIZE(s) \ ((EXT2_SB(s)->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT) ? \ (s)->s_desc_size : EXT2_MIN_DESC_SIZE) and s_desc_size is 0 because parse_extended_opts is called from PRS which is called very early in main() at line 2320, while s_desc_size is set up in ext2fs_initialize, which is not called from main() until mke2fs.c:2353. As a temporary workaround, I notice that ext2fs_initialize sets s_desc_size to the fixed value EXT2_MIN_DESC_SIZE_64BIT, so I changed the #define as follows: #define EXT2_DESC_SIZE(s) \ ((EXT2_SB(s)->s_feature_incompat & EXT4_FEATURE_INCOMPAT_64BIT) ? \ (s)->s_desc_size ?: EXT2_MIN_DESC_SIZE_64BIT : EXT2_MIN_DESC_SIZE) ... which seems to work. (One point that occurred to me while wrestling with this is that the default resize limit of initial size * 1000 should perhaps be clamped to 2^32 if 64bit is not enabled.) -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html