Re: [PATCH v1] xfs: correct nlink printf specifier from hd to PRIu32

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Jun 28, 2022 at 10:45:42PM +0800, hexiaole wrote:
> From: hexiaole <hexiaole@kylinos.cn>
> 
> 1. Description
> libxfs/xfs_log_format.h declare 'di_nlink' as unsigned 32-bit integer:
> 
> typedef struct xfs_icdinode {
>         ...
>         __uint32_t      di_nlink;       /* number of links to file */
>         ...
> } xfs_icdinode_t;
> 
> But logprint/log_misc.c use '%hd' to print 'di_nlink':
> 
> void
> xlog_print_trans_inode_core(xfs_icdinode_t *ip)
> {
>     ...
>     printf(_("nlink %hd uid %d gid %d\n"),
>            ip->di_nlink, ip->di_uid, ip->di_gid);
>     ...
> }
> 
> '%hd' can be 16-bit on many architectures, on these architectures, the 'printf' only print the low 16-bit of 'di_nlink'.
> 
> 2. Reproducer
> 2.1. Commands
> [root@localhost ~]# cd
> [root@localhost ~]# xfs_mkfile 128m 128m.xfs
> [root@localhost ~]# mkfs.xfs 128m.xfs
> [root@localhost ~]# mount 128m.xfs /mnt/
> [root@localhost ~]# cd /mnt/
> [root@localhost mnt]# seq 1 65534|xargs mkdir -p
> [root@localhost mnt]# cd
> [root@localhost ~]# umount /mnt/
> [root@localhost ~]# xfs_logprint 128m.xfs|grep nlink|tail -1
> 
> 2.2. Expect result
> nlink 65536
> 
> 2.3. Actual result
> nlink 0
> ---
>  logprint/log_misc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/logprint/log_misc.c b/logprint/log_misc.c
> index 35e926a3..6add28ed 100644
> --- a/logprint/log_misc.c
> +++ b/logprint/log_misc.c
> @@ -444,7 +444,7 @@ xlog_print_trans_inode_core(
>      printf(_("magic 0x%hx mode 0%ho version %d format %d\n"),
>  	   ip->di_magic, ip->di_mode, (int)ip->di_version,
>  	   (int)ip->di_format);
> -    printf(_("nlink %hd uid %d gid %d\n"),
> +    printf(_("nlink %" PRIu32 " uid %d gid %d\n"),

*Half* decimal?  LOL, I'd forgotten that even exists.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

>  	   ip->di_nlink, ip->di_uid, ip->di_gid);
>      printf(_("atime 0x%llx mtime 0x%llx ctime 0x%llx\n"),
>  		xlog_extract_dinode_ts(ip->di_atime),
> -- 
> 2.27.0
>