nfsd4: allow encoding across page boundaries
After this we can handle for example getattr of very large ACLs.
Read, readdir, readlink are still special cases with their own limits.
Also we can't handle a new operation starting close to the end of a
page.
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index 3ce431b..5d8f915 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1264,6 +1264,10 @@
xdr->end = head->iov_base + PAGE_SIZE - 2 * RPC_MAX_AUTH_SIZE;
/* Tail and page_len should be zero at this point: */
buf->len = buf->head[0].iov_len;
+ xdr->scratch.iov_len = 0;
+ xdr->page_ptr = buf->pages;
+ buf->buflen = PAGE_SIZE * (1 + rqstp->rq_page_end - buf->pages)
+ - 2 * RPC_MAX_AUTH_SIZE;
}
/*
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index bd529e5..d3a576d 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -1624,6 +1624,7 @@
* the head and tail in another page:
*/
return 2 * PAGE_SIZE;
+ case OP_GETATTR:
case OP_READ:
return INT_MAX;
default:
@@ -2560,21 +2561,31 @@
goto out;
}
+static void svcxdr_init_encode_from_buffer(struct xdr_stream *xdr,
+ struct xdr_buf *buf, __be32 *p, int bytes)
+{
+ xdr->scratch.iov_len = 0;
+ memset(buf, 0, sizeof(struct xdr_buf));
+ buf->head[0].iov_base = p;
+ buf->head[0].iov_len = 0;
+ buf->len = 0;
+ xdr->buf = buf;
+ xdr->iov = buf->head;
+ xdr->p = p;
+ xdr->end = (void *)p + bytes;
+ buf->buflen = bytes;
+}
+
__be32 nfsd4_encode_fattr_to_buf(__be32 **p, int words,
struct svc_fh *fhp, struct svc_export *exp,
struct dentry *dentry, u32 *bmval,
struct svc_rqst *rqstp, int ignore_crossmnt)
{
- struct xdr_buf dummy = {
- .head[0] = {
- .iov_base = *p,
- },
- .buflen = words << 2,
- };
+ struct xdr_buf dummy;
struct xdr_stream xdr;
__be32 ret;
- xdr_init_encode(&xdr, &dummy, NULL);
+ svcxdr_init_encode_from_buffer(&xdr, &dummy, *p, words << 2);
ret = nfsd4_encode_fattr(&xdr, fhp, exp, dentry, bmval, rqstp,
ignore_crossmnt);
*p = xdr.p;
@@ -3064,8 +3075,6 @@
if (nfserr)
return nfserr;
- if (resp->xdr.buf->page_len)
- return nfserr_resource;
p = xdr_reserve_space(xdr, 8); /* eof flag and byte count */
if (!p)
@@ -3075,6 +3084,9 @@
if (xdr->end - xdr->p < 1)
return nfserr_resource;
+ if (resp->xdr.buf->page_len)
+ return nfserr_resource;
+
maxcount = svc_max_payload(resp->rqstp);
if (maxcount > read->rd_length)
maxcount = read->rd_length;
@@ -3119,6 +3131,8 @@
- (char *)resp->xdr.buf->head[0].iov_base);
resp->xdr.buf->page_len = maxcount;
xdr->buf->len += maxcount;
+ xdr->page_ptr += v;
+ xdr->buf->buflen = maxcount + PAGE_SIZE - 2 * RPC_MAX_AUTH_SIZE;
xdr->iov = xdr->buf->tail;
/* Use rest of head for padding and remaining ops: */
@@ -3145,6 +3159,11 @@
if (nfserr)
return nfserr;
+
+ p = xdr_reserve_space(xdr, 4);
+ if (!p)
+ return nfserr_resource;
+
if (resp->xdr.buf->page_len)
return nfserr_resource;
if (!*resp->rqstp->rq_next_page)
@@ -3154,10 +3173,6 @@
maxcount = PAGE_SIZE;
- p = xdr_reserve_space(xdr, 4);
- if (!p)
- return nfserr_resource;
-
if (xdr->end - xdr->p < 1)
return nfserr_resource;
@@ -3180,6 +3195,8 @@
- (char *)resp->xdr.buf->head[0].iov_base;
resp->xdr.buf->page_len = maxcount;
xdr->buf->len += maxcount;
+ xdr->page_ptr += 1;
+ xdr->buf->buflen -= PAGE_SIZE;
xdr->iov = xdr->buf->tail;
/* Use rest of head for padding and remaining ops: */
@@ -3206,15 +3223,16 @@
if (nfserr)
return nfserr;
- if (resp->xdr.buf->page_len)
- return nfserr_resource;
- if (!*resp->rqstp->rq_next_page)
- return nfserr_resource;
p = xdr_reserve_space(xdr, NFS4_VERIFIER_SIZE);
if (!p)
return nfserr_resource;
+ if (resp->xdr.buf->page_len)
+ return nfserr_resource;
+ if (!*resp->rqstp->rq_next_page)
+ return nfserr_resource;
+
/* XXX: Following NFSv3, we ignore the READDIR verifier for now. */
WRITE32(0);
WRITE32(0);
@@ -3266,6 +3284,10 @@
xdr->iov = xdr->buf->tail;
+ xdr->page_ptr++;
+ xdr->buf->buflen -= PAGE_SIZE;
+ xdr->iov = xdr->buf->tail;
+
/* Use rest of head for padding and remaining ops: */
resp->xdr.buf->tail[0].iov_base = tailbase;
resp->xdr.buf->tail[0].iov_len = 0;
@@ -3800,6 +3822,8 @@
!nfsd4_enc_ops[op->opnum]);
encoder = nfsd4_enc_ops[op->opnum];
op->status = encoder(resp, op->status, &op->u);
+ xdr_commit_encode(xdr);
+
/* nfsd4_check_resp_size guarantees enough room for error status */
if (!op->status) {
int space_needed = 0;
@@ -3919,6 +3943,8 @@
WARN_ON_ONCE(buf->len != buf->head[0].iov_len + buf->page_len +
buf->tail[0].iov_len);
+ rqstp->rq_next_page = resp->xdr.page_ptr + 1;
+
p = resp->tagp;
*p++ = htonl(resp->taglen);
memcpy(p, resp->tag, resp->taglen);