Re: [PATCH 15/15][e2fsprogs] 64-bit mke2fs cleanup

Goswin von Brederlow
2008-07-16T13:52:05Z

Goswin von Brederlow <goswin-v-b@web.de> writes:

> "Jose R. Santos" <jrs@us.ibm.com> writes:
>
>> diff --git a/misc/mke2fs.c b/misc/mke2fs.c
>> index 7171990..817be56 100644
>> --- a/misc/mke2fs.c
>> +++ b/misc/mke2fs.c
>> @@ -1402,12 +1402,12 @@ static void PRS(int argc, char *argv[])
>>
>> fs_param.s_log_frag_size = fs_param.s_log_block_size;
>>
>> - if (noaction && fs_param.s_blocks_count) {
>> - dev_size = fs_param.s_blocks_count;
>> + if (noaction && ext2fs_blocks_count(&fs_param)) {
>> + dev_size = ext2fs_blocks_count(&fs_param);
>> retval = 0;
>> } else {
>> retry:
>> - retval = ext2fs_get_device_size(device_name,
>> + retval = ext2fs_get_device_size2(device_name,
>> EXT2_BLOCK_SIZE(&fs_param),
>> &dev_size);
>> if ((retval == EFBIG) &&
>
> You should not assume that ext2fs_get_device_size2() will return EFBIG
> if the size exceed 2^32 blocks. The point of ext2fs_get_device_size2()
> was to be able to support more than 2^32 blocks and the library
> function will certainly change to return larger numbers in the future.
>
> So you need something like
>
> if ((retval == EFBIG || dev_size >= (1ULL << 32)) &&
>
> MfG
> Goswin

Actualy that is already a problem. The ext2fs_get_device_size2() only
returns EFBIG if sizeof(dev_size) < sizeof(unsigned long long), which
was the case for blk_t but no longer.

As a result mke2fs no longer stops with the right error on devices >
16TiB. My test device is exactly 32 TiB large and gives the following:

root@beo-13:~# LD_LIBRARY_PATH=/tmpa/ext4 /tmpa/ext4/mke2fs -T ext4dev
-j -m0 /dev/mapper/ext4
mke2fs 1.41.0 (10-Jul-2008)
mke2fs: inode_size (256) * inodes_count (0) too big for a
filesystem with 0 blocks, specify higher inode_ratio (-i)
or lower inode count (-N).

I'm guessing somewhere along the line it converts to 32bit choping of
the higher bits.

MfG
Goswin