Re: [PATCH v2] src: fix detached_mounts_propagation compile errors

[Ziyang Zhang <ZiyangZhang@linux.alibaba.com>]

On 2023/4/25 10:07, Yang Xu (Fujitsu) wrote:
> 
> 
> on 2023/04/25 9:59, Ziyang Zhang wrote:
>> On 2023/4/25 09:28, Yang Xu (Fujitsu) wrote:
>>>
>>
>> [...]
>>
>>>>
>>>> Looks like not help [1]. The src/feature.c through global.h -> xfs/xfs.h
>>>> -> xfs/linux.h -> linux/fs.h to include linux/mount.h, then it include
>>>> "vfs/missing.h" manually. As you add "<sys/mount.h>" to vfs/missing.h,
>>>> so there's a conflict.
>>>
>>> Yes, here is a complex problem than ltp because global.h includes
>>> <linux/mount.h>. We don't include <sys/mount.h> or <linux/mount.h>
>>> together on older glibc(glibc 2.36.6).  Newer glibc(glibc-2.37-1)[1]
>>> seems has sloved this problem.
>>>
>>> [1]https://sourceware.org/git/?p=glibc.git;a=commit;h=774058d72942249f71d74e7f2b639f77184160a6
>>>
>>> I guess we can not use <sys/mount.h> header,
>>> then compile info as below:
>>> detached_mounts_propagation.c: In function 'main':
>>> detached_mounts_propagation.c:129:15: warning: implicit declaration of
>>> function 'mount' [-Wimplicit-function-declaration]
>>>     129 |         ret = mount(NULL, base_dir, NULL, MS_REC | MS_SHARED,
>>> NULL);
>>>         |               ^~~~~
>>> detached_mounts_propagation.c:176:23: warning: implicit declaration of
>>> function 'umount2'; did you mean 'sys_umount2'?
>>> [-Wimplicit-function-declaration]
>>>     176 |                 ret = umount2(target, MNT_DETACH);
>>>         |                       ^~~~~~~
>>>         |                       sys_umount2
>>>
>>>
>>> then we can use syscall wrapper directly instead of glibc wrapper
>>> --- a/src/detached_mounts_propagation.c
>>> +++ b/src/detached_mounts_propagation.c
>>> @@ -20,7 +20,6 @@
>>>    #include <stdio.h>
>>>    #include <stdlib.h>
>>>    #include <string.h>
>>> -#include <sys/mount.h>
>>>    #include <sys/stat.h>
>>>    #include <sys/syscall.h>
>>>    #include <sys/types.h>
>>> @@ -127,7 +126,7 @@ int main(int argc, char *argv[])
>>>           if (ret < 0)
>>>                   exit_log("%m - Failed to create new mount namespace");
>>>
>>> -       ret = mount(NULL, base_dir, NULL, MS_REC | MS_SHARED, NULL);
>>> +       ret = sys_mount(NULL, base_dir, NULL, MS_REC | MS_SHARED, NULL);
>>>           if (ret < 0)
>>>                   exit_log("%m - Failed to make base_dir shared mountpoint");
>>>
>>> @@ -174,7 +173,7 @@ int main(int argc, char *argv[])
>>>                   }
>>>                   close(fd_tree);
>>>
>>> -               ret = umount2(target, MNT_DETACH);
>>> +               ret = sys_umount2(target, MNT_DETACH);
>>>                   if (ret < 0) {
>>>                           fprintf(stderr, "%m - Failed to unmount %s",
>>> target);
>>>                           exit_code = EXIT_FAILURE;
>>>
>>>
>>> Best Regards
>>> Yang Xu
>>>
>>
>> Hi Yang,
>>
>> You patch works for me(kernel: 5.10.134, glibc:2.36). I think we could just
>> modify detached_mounts_propagation.c to solve this problem.
> 
> OK, @Gao @Ziyang, so should I send a patch or you send it?
> 
> Best Regards
> Yang Xu

Hi, you can send it. :) Thanks.