2022-06-02 06:40:36

by Dongliang Mu

Subject: [PATCH] fs: nfsd: make destory function more elegant

From: Dongliang Mu <[email protected]>

In init_nfsd, the undo operation of create_proc_exports_entry is:

remove_proc_entry("fs/nfs/exports", NULL);
remove_proc_entry("fs/nfs", NULL);

This may lead to maintaince issue. Declare the undo function
destroy_proc_exports_entry based on CONFIG_PROC_FS

Signed-off-by: Dongliang Mu <[email protected]>
---
fs/nfsd/nfsctl.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 0621c2faf242..83b34ccbef5a 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -1450,11 +1450,21 @@ static int create_proc_exports_entry(void)
}
return 0;
}
+
+static void destroy_proc_exports_entry(void)
+{
+ remove_proc_entry("fs/nfs/exports", NULL);
+ remove_proc_entry("fs/nfs", NULL);
+}
#else /* CONFIG_PROC_FS */
static int create_proc_exports_entry(void)
{
return 0;
}
+
+static void destroy_proc_exports_entry(void)
+{
+}
#endif

unsigned int nfsd_net_id;
@@ -1555,8 +1565,7 @@ static int __init init_nfsd(void)
out_free_subsys:
unregister_pernet_subsys(&nfsd_net_ops);
out_free_exports:
- remove_proc_entry("fs/nfs/exports", NULL);
- remove_proc_entry("fs/nfs", NULL);
+ destroy_proc_exports_entry();
out_free_lockd:
nfsd_lockd_shutdown();
nfsd_drc_slab_free();
@@ -1576,8 +1585,7 @@ static void __exit exit_nfsd(void)
unregister_cld_notifier();
unregister_pernet_subsys(&nfsd_net_ops);
nfsd_drc_slab_free();
- remove_proc_entry("fs/nfs/exports", NULL);
- remove_proc_entry("fs/nfs", NULL);
+ destroy_proc_exports_entry();
nfsd_stat_shutdown();
nfsd_lockd_shutdown();
nfsd4_free_slabs();
--
2.25.1

2022-06-02 16:08:32

by Chuck Lever

Subject: Re: [PATCH] nfsd: make destory function more elegant

> On Jun 2, 2022, at 1:56 AM, Dongliang Mu <[email protected]> wrote:
>
> From: Dongliang Mu <[email protected]>
>
> In init_nfsd, the undo operation of create_proc_exports_entry is:
>
> remove_proc_entry("fs/nfs/exports", NULL);
> remove_proc_entry("fs/nfs", NULL);
>
> This may lead to maintaince issue. Declare the undo function

"maintenance"


> destroy_proc_exports_entry based on CONFIG_PROC_FS

IIUC, the issue is that if CONFIG_PROC_FS is not set,
fs/nfsd/nfsctl.c fails to compile?


> Signed-off-by: Dongliang Mu <[email protected]>
> ---
> fs/nfsd/nfsctl.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index 0621c2faf242..83b34ccbef5a 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -1450,11 +1450,21 @@ static int create_proc_exports_entry(void)
> }
> return 0;
> }
> +
> +static void destroy_proc_exports_entry(void)
> +{
> + remove_proc_entry("fs/nfs/exports", NULL);
> + remove_proc_entry("fs/nfs", NULL);
> +}
> #else /* CONFIG_PROC_FS */
> static int create_proc_exports_entry(void)
> {
> return 0;
> }
> +
> +static void destroy_proc_exports_entry(void)
> +{
> +}
> #endif
>
> unsigned int nfsd_net_id;
> @@ -1555,8 +1565,7 @@ static int __init init_nfsd(void)
> out_free_subsys:
> unregister_pernet_subsys(&nfsd_net_ops);
> out_free_exports:
> - remove_proc_entry("fs/nfs/exports", NULL);
> - remove_proc_entry("fs/nfs", NULL);
> + destroy_proc_exports_entry();
> out_free_lockd:
> nfsd_lockd_shutdown();
> nfsd_drc_slab_free();
> @@ -1576,8 +1585,7 @@ static void __exit exit_nfsd(void)
> unregister_cld_notifier();
> unregister_pernet_subsys(&nfsd_net_ops);
> nfsd_drc_slab_free();
> - remove_proc_entry("fs/nfs/exports", NULL);
> - remove_proc_entry("fs/nfs", NULL);
> + destroy_proc_exports_entry();
> nfsd_stat_shutdown();
> nfsd_lockd_shutdown();
> nfsd4_free_slabs();
> --
> 2.25.1
>

--
Chuck Lever

2022-06-03 13:58:24

by Dongliang Mu

Subject: Re: [PATCH] nfsd: make destory function more elegant

On Thu, Jun 2, 2022 at 10:30 PM Chuck Lever III <[email protected]> wrote:
>
>
>
> > On Jun 2, 2022, at 1:56 AM, Dongliang Mu <[email protected]> wrote:
> >
> > From: Dongliang Mu <[email protected]>
> >
> > In init_nfsd, the undo operation of create_proc_exports_entry is:
> >
> > remove_proc_entry("fs/nfs/exports", NULL);
> > remove_proc_entry("fs/nfs", NULL);
> >
> > This may lead to maintaince issue. Declare the undo function
>
> "maintenance"

Sorry for the typo.

>
>
> > destroy_proc_exports_entry based on CONFIG_PROC_FS
>
> IIUC, the issue is that if CONFIG_PROC_FS is not set,
> fs/nfsd/nfsctl.c fails to compile?

The answer is no. There is no bug in the code.

At first, I thought this might cause the miscompilation or bug. But
actually the code is fine.

Because remove_proc_entry is defined as an empty function if
CONFIG_PROC_FS is not set,

>
>
> > Signed-off-by: Dongliang Mu <[email protected]>
> > ---
> > fs/nfsd/nfsctl.c | 16 ++++++++++++----
> > 1 file changed, 12 insertions(+), 4 deletions(-)
> >
> > diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> > index 0621c2faf242..83b34ccbef5a 100644
> > --- a/fs/nfsd/nfsctl.c
> > +++ b/fs/nfsd/nfsctl.c
> > @@ -1450,11 +1450,21 @@ static int create_proc_exports_entry(void)
> > }
> > return 0;
> > }
> > +
> > +static void destroy_proc_exports_entry(void)
> > +{
> > + remove_proc_entry("fs/nfs/exports", NULL);
> > + remove_proc_entry("fs/nfs", NULL);
> > +}
> > #else /* CONFIG_PROC_FS */
> > static int create_proc_exports_entry(void)
> > {
> > return 0;
> > }
> > +
> > +static void destroy_proc_exports_entry(void)
> > +{
> > +}
> > #endif
> >
> > unsigned int nfsd_net_id;
> > @@ -1555,8 +1565,7 @@ static int __init init_nfsd(void)
> > out_free_subsys:
> > unregister_pernet_subsys(&nfsd_net_ops);
> > out_free_exports:
> > - remove_proc_entry("fs/nfs/exports", NULL);
> > - remove_proc_entry("fs/nfs", NULL);
> > + destroy_proc_exports_entry();
> > out_free_lockd:
> > nfsd_lockd_shutdown();
> > nfsd_drc_slab_free();
> > @@ -1576,8 +1585,7 @@ static void __exit exit_nfsd(void)
> > unregister_cld_notifier();
> > unregister_pernet_subsys(&nfsd_net_ops);
> > nfsd_drc_slab_free();
> > - remove_proc_entry("fs/nfs/exports", NULL);
> > - remove_proc_entry("fs/nfs", NULL);
> > + destroy_proc_exports_entry();
> > nfsd_stat_shutdown();
> > nfsd_lockd_shutdown();
> > nfsd4_free_slabs();
> > --
> > 2.25.1
> >
>
> --
> Chuck Lever
>
>
>

2022-06-03 18:29:59

by Chuck Lever

Subject: Re: [PATCH] nfsd: make destory function more elegant

> On Jun 3, 2022, at 9:50 AM, Dongliang Mu <[email protected]> wrote:
>
> On Thu, Jun 2, 2022 at 10:30 PM Chuck Lever III <[email protected]> wrote:
>>
>>
>>
>>> On Jun 2, 2022, at 1:56 AM, Dongliang Mu <[email protected]> wrote:
>>>
>>> From: Dongliang Mu <[email protected]>
>>>
>>> In init_nfsd, the undo operation of create_proc_exports_entry is:
>>>
>>> remove_proc_entry("fs/nfs/exports", NULL);
>>> remove_proc_entry("fs/nfs", NULL);
>>>
>>> This may lead to maintaince issue. Declare the undo function
>>
>> "maintenance"
>
> Sorry for the typo.
>
>>
>>
>>> destroy_proc_exports_entry based on CONFIG_PROC_FS
>>
>> IIUC, the issue is that if CONFIG_PROC_FS is not set,
>> fs/nfsd/nfsctl.c fails to compile?
>
> The answer is no. There is no bug in the code.
>
> At first, I thought this might cause the miscompilation or bug. But
> actually the code is fine.
>
> Because remove_proc_entry is defined as an empty function if
> CONFIG_PROC_FS is not set,

Code inspection does suggest there could be a problem,
but I'm glad there isn't one. I can drop this one.


>>> Signed-off-by: Dongliang Mu <[email protected]>
>>> ---
>>> fs/nfsd/nfsctl.c | 16 ++++++++++++----
>>> 1 file changed, 12 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
>>> index 0621c2faf242..83b34ccbef5a 100644
>>> --- a/fs/nfsd/nfsctl.c
>>> +++ b/fs/nfsd/nfsctl.c
>>> @@ -1450,11 +1450,21 @@ static int create_proc_exports_entry(void)
>>> }
>>> return 0;
>>> }
>>> +
>>> +static void destroy_proc_exports_entry(void)
>>> +{
>>> + remove_proc_entry("fs/nfs/exports", NULL);
>>> + remove_proc_entry("fs/nfs", NULL);
>>> +}
>>> #else /* CONFIG_PROC_FS */
>>> static int create_proc_exports_entry(void)
>>> {
>>> return 0;
>>> }
>>> +
>>> +static void destroy_proc_exports_entry(void)
>>> +{
>>> +}
>>> #endif
>>>
>>> unsigned int nfsd_net_id;
>>> @@ -1555,8 +1565,7 @@ static int __init init_nfsd(void)
>>> out_free_subsys:
>>> unregister_pernet_subsys(&nfsd_net_ops);
>>> out_free_exports:
>>> - remove_proc_entry("fs/nfs/exports", NULL);
>>> - remove_proc_entry("fs/nfs", NULL);
>>> + destroy_proc_exports_entry();
>>> out_free_lockd:
>>> nfsd_lockd_shutdown();
>>> nfsd_drc_slab_free();
>>> @@ -1576,8 +1585,7 @@ static void __exit exit_nfsd(void)
>>> unregister_cld_notifier();
>>> unregister_pernet_subsys(&nfsd_net_ops);
>>> nfsd_drc_slab_free();
>>> - remove_proc_entry("fs/nfs/exports", NULL);
>>> - remove_proc_entry("fs/nfs", NULL);
>>> + destroy_proc_exports_entry();
>>> nfsd_stat_shutdown();
>>> nfsd_lockd_shutdown();
>>> nfsd4_free_slabs();
>>> --
>>> 2.25.1
>>>
>>
>> --
>> Chuck Lever

--
Chuck Lever