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SubjectRe: [PATCH] NFSD: Fix the share reservation conflict to courteous server logic in nfs4_upgrade_open()
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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
>
>
>

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