missed nfs list. resend.
On Fri, Apr 5, 2019 at 2:10 PM Murphy Zhou <jencce.kernel@xxxxxxxxx> wrote:
>
>
>
> On Fri, Apr 5, 2019 at 14:08 Murphy Zhou <jencce.kernel@xxxxxxxxx> wrote:
>>
>>
>>
>> On Fri, Apr 5, 2019 at 06:47 NeilBrown <neilb@xxxxxxxx> wrote:
>>>
>>> On Thu, Apr 04 2019, Murphy Zhou wrote:
>>>
>>> > After this commit
>>> > f875a79 nfsd: allow nfsv3 readdir request to be larger.
>>> > nfsv3 readdir request size can be larger than PAGE_SIZE. So if the
>>> > directory been read is large enough, we can use multiple pages
>>> > in rq_respages. Update buffer count and page pointers like we do
>>> > in readdirplus to make this happen.
>>> >
>>> > Now listing a directory within 3000 files will panic because we
>>> > are counting in a wrong way and would write on random page.
>>> >
>>> > Fixes: f875a79 "nfsd: allow nfsv3 readdir request to be larger"
>>> > Signed-off-by: Murphy Zhou <jencce.kernel@xxxxxxxxx>
>>> > ---
>>> >
>>> > v2:
>>> > fix nfs3svc_decode_readdirargs to set page pointers like decode_readdirplusargs
>>> > do not test pointers in encode_entry as we've fixed them when decoding
>>> >
>>> > fs/nfsd/nfs3proc.c | 17 +++++++++++++++--
>>> > fs/nfsd/nfs3xdr.c | 11 +++++++++--
>>> > 2 files changed, 24 insertions(+), 4 deletions(-)
>>> >
>>> > diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c
>>> > index 8f933e8..9bc32af 100644
>>> > --- a/fs/nfsd/nfs3proc.c
>>> > +++ b/fs/nfsd/nfs3proc.c
>>> > @@ -442,7 +442,9 @@
>>> > struct nfsd3_readdirargs *argp = rqstp->rq_argp;
>>> > struct nfsd3_readdirres *resp = rqstp->rq_resp;
>>> > __be32 nfserr;
>>> > - int count;
>>> > + int count = 0;
>>> > + struct page **p;
>>> > + caddr_t page_addr = NULL;
>>> >
>>> > dprintk("nfsd: READDIR(3) %s %d bytes at %d\n",
>>> > SVCFH_fmt(&argp->fh),
>>> > @@ -462,7 +464,18 @@
>>> > nfserr = nfsd_readdir(rqstp, &resp->fh, (loff_t*) &argp->cookie,
>>> > &resp->common, nfs3svc_encode_entry);
>>> > memcpy(resp->verf, argp->verf, 8);
>>> > - resp->count = resp->buffer - argp->buffer;
>>> > + count = 0;
>>>
>>> Thanks - looks good.
>>> Setting 'count' to zero a second time looks a bit clumsy, but that is a
>>> minor detail.
>
>
> Save some space in the stack :)
>
> Thanks for your review!
>
> M
>>>
>>>
>>>
>>> Reviewed-by: NeilBrown <neilb@xxxxxxxx>
>>>
>>> Thanks,
>>> NeilBrown
>>>
>>>
>>> > + for (p = rqstp->rq_respages + 1; p < rqstp->rq_next_page; p++) {
>>> > + page_addr = page_address(*p);
>>> > +
>>> > + if (((caddr_t)resp->buffer >= page_addr) &&
>>> > + ((caddr_t)resp->buffer < page_addr + PAGE_SIZE)) {
>>> > + count += (caddr_t)resp->buffer - page_addr;
>>> > + break;
>>> > + }
>>> > + count += PAGE_SIZE;
>>> > + }
>>> > + resp->count = count >> 2;
>>> > if (resp->offset) {
>>> > loff_t offset = argp->cookie;
>>> >
>>> > diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c
>>> > index 93fea24..8d78912 100644
>>> > --- a/fs/nfsd/nfs3xdr.c
>>> > +++ b/fs/nfsd/nfs3xdr.c
>>> > @@ -573,6 +573,7 @@ void fill_post_wcc(struct svc_fh *fhp)
>>> > nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
>>> > {
>>> > struct nfsd3_readdirargs *args = rqstp->rq_argp;
>>> > + int len;
>>> > u32 max_blocksize = svc_max_payload(rqstp);
>>> >
>>> > p = decode_fh(p, &args->fh);
>>> > @@ -582,8 +583,14 @@ void fill_post_wcc(struct svc_fh *fhp)
>>> > args->verf = p; p += 2;
>>> > args->dircount = ~0;
>>> > args->count = ntohl(*p++);
>>> > - args->count = min_t(u32, args->count, max_blocksize);
>>> > - args->buffer = page_address(*(rqstp->rq_next_page++));
>>> > + len = args->count = min_t(u32, args->count, max_blocksize);
>>> > +
>>> > + while (len > 0) {
>>> > + struct page *p = *(rqstp->rq_next_page++);
>>> > + if (!args->buffer)
>>> > + args->buffer = page_address(p);
>>> > + len -= PAGE_SIZE;
>>> > + }
>>> >
>>> > return xdr_argsize_check(rqstp, p);
>>> > }
>>> > --
>>> > 1.8.3.1
