> On Nov 20, 2020, at 7:59 PM, bfields@xxxxxxxxxxxx wrote:
>
> On Fri, Nov 20, 2020 at 03:33:51PM -0500, Chuck Lever wrote:
>> Code inspection shows that the server's NFSv3 READDIR implementation
>> returns the same offset cookie as the client sent, instead of the
>> last cookie it returns in the reply's dirlist. This is unlike the
>> NFSv2 READDIR, NFSv3 READDIRPLUS, and NFSv4 READDIR implementations,
>> and it's been like this since the beginning of kernel git history.
>
> Surely this should have caused actual failures in practice.
>
>> I copied the logic from nfsd3_proc_readdirplus().
>>
>> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
>> ---
>> fs/nfsd/nfs3proc.c | 7 ++++---
>> 1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
>> index d9be589fed15..e0ad18d6b5a8 100644
>> --- a/fs/nfsd/nfs3proc.c
>> +++ b/fs/nfsd/nfs3proc.c
>> @@ -430,6 +430,7 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
>> struct nfsd3_readdirargs *argp = rqstp->rq_argp;
>> struct nfsd3_readdirres *resp = rqstp->rq_resp;
>> int count = 0;
>> + loff_t offset;
>> struct page **p;
>> caddr_t page_addr = NULL;
>>
>> @@ -448,7 +449,9 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
>> resp->common.err = nfs_ok;
>> resp->buffer = argp->buffer;
>> resp->rqstp = rqstp;
>> - resp->status = nfsd_readdir(rqstp, &resp->fh, (loff_t *)&argp->cookie,
>
> Doesn't nfsd_readdir() update argp->cookie to point to the last offset?
>
>> + offset = argp->cookie;
>> +
>> + resp->status = nfsd_readdir(rqstp, &resp->fh, &offset,
>> &resp->common, nfs3svc_encode_entry);
>> memcpy(resp->verf, argp->verf, 8);
>> count = 0;
>> @@ -464,8 +467,6 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp)
>> }
>> resp->count = count >> 2;
>> if (resp->offset) {
>> - loff_t offset = argp->cookie;
>
> So, this shouldn't be equal to the initial cookie any more.
>
> Am I missing something?
No, my mistake. This works as we expect. Thanks for the review!
However, I find it confusing that nfsd3_proc_readdir() is structured
differently than the other three readdir proc methods, and for no
documented reason.
Would you still be willing to consider this patch relabeled as a clean-up ?
> --b.
>
>> -
>> if (unlikely(resp->offset1)) {
>> /* we ended up with offset on a page boundary */
>> *resp->offset = htonl(offset >> 32);
>>
--
Chuck Lever
