diff mbox series

NFSD: Fix the share reservation conflict to courteous server logic in nfs4_upgrade_open()

Message ID 7ed2d8f1ee8c441a13b450c5e5c50f13fae3a2b9.1667114760.git.christophe.jaillet@wanadoo.fr
State New
Headers
Series NFSD: Fix the share reservation conflict to courteous server logic in nfs4_upgrade_open() |

Commit Message

Christophe JAILLET Oct. 30, 2022, 7:26 a.m. UTC 
  'status != nfserr_share_denied' is known to be true because we test
'status == nfs_ok' the line just above.

So nfs4_resolve_deny_conflicts_locked() can never be called.

Fix the logic and avoid the dead code.

Fixes: 3d6942715180 ("NFSD: add support for share reservation conflict to courteous server")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
This patch is speculative.
It is compile tested only.

REVIEW WITH CARE.
---
 fs/nfsd/nfs4state.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

Comments

Chuck Lever Oct. 30, 2022, 3:26 p.m. UTC | #1 
> On Oct 30, 2022, at 3:26 AM, Christophe JAILLET <christophe.jaillet@wanadoo.fr> wrote:
> 
> 'status != nfserr_share_denied' is known to be true because we test
> 'status == nfs_ok' the line just above.
> 
> So nfs4_resolve_deny_conflicts_locked() can never be called.
> 
> Fix the logic and avoid the dead code.
> 
> Fixes: 3d6942715180 ("NFSD: add support for share reservation conflict to courteous server")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> This patch is speculative.
> It is compile tested only.
> 
> REVIEW WITH CARE.
> ---
> fs/nfsd/nfs4state.c | 14 ++++++--------
> 1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index 1ded89235111..de0565e9485c 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -5260,15 +5260,13 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp,
> 	spin_lock(&fp->fi_lock);
> 	status = nfs4_file_check_deny(fp, open->op_share_deny);

I agree there's dead code here. I believe the bug is the first check is
supposed to be "if (status != nfs_ok)". I will let Dai have a look at
this to confirm.

But, in the fix, let's replace this logic with "switch (status) { }".


> 	if (status == nfs_ok) {
> -		if (status != nfserr_share_denied) {
> -			set_deny(open->op_share_deny, stp);
> -			fp->fi_share_deny |=
> +		set_deny(open->op_share_deny, stp);
> +		fp->fi_share_deny |=
> 				(open->op_share_deny & NFS4_SHARE_DENY_BOTH);
> -		} else {
> -			if (nfs4_resolve_deny_conflicts_locked(fp, false,
> -					stp, open->op_share_deny, false))
> -				status = nfserr_jukebox;
> -		}
> +	} else if (status == nfserr_share_denied) {
> +		if (nfs4_resolve_deny_conflicts_locked(fp, false, stp,
> +				open->op_share_deny, false))
> +			status = nfserr_jukebox;
> 	}
> 	spin_unlock(&fp->fi_lock);
> 
> -- 
> 2.34.1
> 

--
Chuck Lever
dai.ngo@oracle.com Oct. 30, 2022, 4:32 p.m. UTC | #2 
On 10/30/22 8:26 AM, Chuck Lever III wrote:
>
>> On Oct 30, 2022, at 3:26 AM, Christophe JAILLET <christophe.jaillet@wanadoo.fr> wrote:
>>
>> 'status != nfserr_share_denied' is known to be true because we test
>> 'status == nfs_ok' the line just above.
>>
>> So nfs4_resolve_deny_conflicts_locked() can never be called.
>>
>> Fix the logic and avoid the dead code.
>>
>> Fixes: 3d6942715180 ("NFSD: add support for share reservation conflict to courteous server")
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
>> ---
>> This patch is speculative.
>> It is compile tested only.
>>
>> REVIEW WITH CARE.
>> ---
>> fs/nfsd/nfs4state.c | 14 ++++++--------
>> 1 file changed, 6 insertions(+), 8 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index 1ded89235111..de0565e9485c 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -5260,15 +5260,13 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp,
>> 	spin_lock(&fp->fi_lock);
>> 	status = nfs4_file_check_deny(fp, open->op_share_deny);
> I agree there's dead code here. I believe the bug is the first check is
> supposed to be "if (status != nfs_ok)". I will let Dai have a look at
> this to confirm.

Yes, it's actually a bug when nfs4_file_check_deny returns
nfserr_share_denied we won't try to resolve the conflict at all.

Thanks for catching this!
-Dai

>
> But, in the fix, let's replace this logic with "switch (status) { }".
>
>
>> 	if (status == nfs_ok) {
>> -		if (status != nfserr_share_denied) {
>> -			set_deny(open->op_share_deny, stp);
>> -			fp->fi_share_deny |=
>> +		set_deny(open->op_share_deny, stp);
>> +		fp->fi_share_deny |=
>> 				(open->op_share_deny & NFS4_SHARE_DENY_BOTH);
>> -		} else {
>> -			if (nfs4_resolve_deny_conflicts_locked(fp, false,
>> -					stp, open->op_share_deny, false))
>> -				status = nfserr_jukebox;
>> -		}
>> +	} else if (status == nfserr_share_denied) {
>> +		if (nfs4_resolve_deny_conflicts_locked(fp, false, stp,
>> +				open->op_share_deny, false))
>> +			status = nfserr_jukebox;
>> 	}
>> 	spin_unlock(&fp->fi_lock);
>>
>> -- 
>> 2.34.1
>>
> --
> Chuck Lever
>
>
>
diff mbox series

Patch

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 1ded89235111..de0565e9485c 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -5260,15 +5260,13 @@  nfs4_upgrade_open(struct svc_rqst *rqstp, struct nfs4_file *fp,
 	spin_lock(&fp->fi_lock);
 	status = nfs4_file_check_deny(fp, open->op_share_deny);
 	if (status == nfs_ok) {
-		if (status != nfserr_share_denied) {
-			set_deny(open->op_share_deny, stp);
-			fp->fi_share_deny |=
+		set_deny(open->op_share_deny, stp);
+		fp->fi_share_deny |=
 				(open->op_share_deny & NFS4_SHARE_DENY_BOTH);
-		} else {
-			if (nfs4_resolve_deny_conflicts_locked(fp, false,
-					stp, open->op_share_deny, false))
-				status = nfserr_jukebox;
-		}
+	} else if (status == nfserr_share_denied) {
+		if (nfs4_resolve_deny_conflicts_locked(fp, false, stp,
+				open->op_share_deny, false))
+			status = nfserr_jukebox;
 	}
 	spin_unlock(&fp->fi_lock);