Hi,
> On Thu, Jun 17, 2021 at 06:12:56PM +0800, Wang Yugui wrote:
> > the major/minor value of statx(kernel samples/vfs/test-statx.c) does not
> > match /usr/bin/stat.
> >
> > major/minor of statx result seems be truncated by something like
> > old_decode_dev()?
>
> I've checked the code first, both stat/statx seem to be doing the same
> thing.
>
> > [root@T640 vfs]# ./test-statx /ssd/
> > statx(/ssd/) = 0
> > results=1fff
> > Size: 200 Blocks: 0 IO Block: 4096 directory
> > Device: 00:31 Inode: 256 Links: 1
>
> So Device is 00:31, printed as two fields in hex.
>
> > Access: (0755/drwxr-xr-x) Uid: 0 Gid: 0
> > Access: 2021-06-16 19:16:56.644344956+0800
> > Modify: 2021-05-06 16:14:33.676248229+0800
> > Change: 2021-05-06 16:14:33.676248229+0800
> > Birth: 2020-11-18 14:03:35.324915316+0800
> > Attributes: 0000000000002000 (........ ........ ........ ........ ........ ..-..... ..?-.... .---.-..)
> > [root@T640 vfs]# stat /ssd/
> > File: ‘/ssd/’
> > Size: 200 Blocks: 0 IO Block: 4096 directory
> > Device: 31h/49d Inode: 256 Links: 1
>
> And here it's also 31, the 'h' suffix means it's hexadecimal and "49d"
> si the same value in decimal.
>
> > Access: (0755/drwxr-xr-x) Uid: ( 0/ root) Gid: ( 0/ root)
> > Access: 2021-06-16 19:16:56.644344956 +0800
> > Modify: 2021-05-06 16:14:33.676248229 +0800
> > Change: 2021-05-06 16:14:33.676248229 +0800
> > Birth: -
> >
> > vfat output sample:
> > [root@T640 vfs]# ./test-statx /boot/efi/
> > statx(/boot/efi/) = 0
> > results=17ff
> > Size: 4096 Blocks: 8 IO Block: 4096 directory
> > Device: 08:01 Inode: 1 Links: 3
>
> 08:01
>
> > Access: (0700/drwx------) Uid: 0 Gid: 0
> > Access: 1970-01-01 08:00:00.000000000+0800
> > Modify: 1970-01-01 08:00:00.000000000+0800
> > Change: 1970-01-01 08:00:00.000000000+0800
> > Attributes: 0000000000002000 (........ ........ ........ ........ ........ ..-..... ..?-.... ........)
> > [root@T640 vfs]# stat /boot/efi/
> > File: ‘/boot/efi/’
> > Size: 4096 Blocks: 8 IO Block: 4096 directory
> > Device: 801h/2049d Inode: 1 Links: 3
>
> 801h == 0801h the same value, so it's just a matter of formatting the
> output and the values are indeed the same.
>
> If you change the format in test-statx.c to "%2xh/%2dd" and the value
> to "(stx->stx_dev_major << 8) + stx->stx_dev_minor", the output is
> exactly the same.
'/bin/stat' output (struct stat).st_dev in both hex and decimal.
coreutils-8.32/src/stat.c
case 'd':
out_uint (pformat, prefix_len, statbuf->st_dev);
break;
case 'D':
out_uint_x (pformat, prefix_len, statbuf->st_dev);
break;
But I thought it output the major and minor of (struct stat).st_dev.
That is my bad. Thanks a lot.
Best Regards
Wang Yugui (wangyugui@xxxxxxxxxxxx)
2021/06/24
