Commit 3c86794a authored by Murphy Zhou's avatar Murphy Zhou Committed by J. Bruce Fields
Browse files

nfsd/nfsd3_proc_readdir: fix buffer count and page pointers 



After this commit
  f875a792 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: f875a792 "nfsd: allow nfsv3 readdir request to be larger"
Signed-off-by: default avatarMurphy Zhou <jencce.kernel@gmail.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent d58431ea

fs/nfsd/nfs3proc.c

+15 −2
Original line number Diff line number Diff line
@@ -442,7 +442,9 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp) 
	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 @@ nfsd3_proc_readdir(struct svc_rqst *rqstp) 
	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;

	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;

fs/nfsd/nfs3xdr.c

+9 −2
Original line number Diff line number Diff line
@@ -573,6 +573,7 @@ int 
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 @@ nfs3svc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p) 
	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);

}

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