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nfsd4: allow exotic read compounds

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I'm not sure why a client would want to stuff multiple reads in a
single compound rpc, but it's legal for them to do it, and we should
really support it.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
J. Bruce Fields 2014-03-18 17:44:10 -04:00
parent fec25fa4ad
commit b042098063
2 changed files with 25 additions and 38 deletions
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2
Documentation/filesystems/nfs/nfs41-server.txt
View File

@ -176,7 +176,5 @@ Nonstandard compound limitations:
ca_maxrequestsize request and a ca_maxresponsesize reply, so we may
fail to live up to the promise we made in CREATE_SESSION fore channel
negotiation.
* No more than one read-like operation allowed per compound; encoding
replies that cross page boundaries (except for read data) not handled.
See also http://wiki.linux-nfs.org/wiki/index.php/Server_4.0_and_4.1_issues.

61
fs/nfsd/nfs4xdr.c
View File

@ -3139,28 +3139,34 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
struct xdr_stream *xdr = &resp->xdr;
u32 eof;
int v;
struct page *page;
int starting_len = xdr->buf->len - 8;
int space_left;
long len;
int thislen;
__be32 nfserr;
__be32 tmp;
__be32 *p;
u32 zzz = 0;
int pad;
len = maxcount;
v = 0;
while (len) {
int thislen;
page = *(resp->rqstp->rq_next_page);
if (!page) { /* ran out of pages */
maxcount -= len;
break;
}
thislen = (void *)xdr->end - (void *)xdr->p;
if (len < thislen)
thislen = len;
p = xdr_reserve_space(xdr, (thislen+3)&~3);
WARN_ON_ONCE(!p);
resp->rqstp->rq_vec[v].iov_base = p;
resp->rqstp->rq_vec[v].iov_len = thislen;
v++;
len -= thislen;
while (len) {
thislen = min_t(long, len, PAGE_SIZE);
resp->rqstp->rq_vec[v].iov_base = page_address(page);
p = xdr_reserve_space(xdr, (thislen+3)&~3);
WARN_ON_ONCE(!p);
resp->rqstp->rq_vec[v].iov_base = p;
resp->rqstp->rq_vec[v].iov_len = thislen;
resp->rqstp->rq_next_page++;
v++;
len -= thislen;
}
@ -3170,6 +3176,7 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
read->rd_vlen, &maxcount);
if (nfserr)
return nfserr;
xdr_truncate_encode(xdr, starting_len + 8 + ((maxcount+3)&~3));
eof = (read->rd_offset + maxcount >=
read->rd_fhp->fh_dentry->d_inode->i_size);
@ -3179,27 +3186,9 @@ static __be32 nfsd4_encode_readv(struct nfsd4_compoundres *resp,
tmp = htonl(maxcount);
write_bytes_to_xdr_buf(xdr->buf, starting_len + 4, &tmp, 4);
resp->xdr.buf->page_len = maxcount;
xdr->buf->len += maxcount;
xdr->page_ptr += v;
xdr->iov = xdr->buf->tail;
/* Use rest of head for padding and remaining ops: */
resp->xdr.buf->tail[0].iov_base = xdr->p;
resp->xdr.buf->tail[0].iov_len = 0;
if (maxcount&3) {
p = xdr_reserve_space(xdr, 4);
WRITE32(0);
resp->xdr.buf->tail[0].iov_base += maxcount&3;
resp->xdr.buf->tail[0].iov_len = 4 - (maxcount&3);
xdr->buf->len -= (maxcount&3);
}
space_left = min_t(int, (void *)xdr->end - (void *)xdr->p,
xdr->buf->buflen - xdr->buf->len);
xdr->buf->buflen = xdr->buf->len + space_left;
xdr->end = (__be32 *)((void *)xdr->end + space_left);
pad = (maxcount&3) ? 4 - (maxcount&3) : 0;
write_bytes_to_xdr_buf(xdr->buf, starting_len + 8 + maxcount,
&zzz, pad);
return 0;
}
@ -3224,15 +3213,15 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, __be32 nfserr,
WARN_ON_ONCE(resp->rqstp->rq_splice_ok);
return nfserr_resource;
}
if (resp->xdr.buf->page_len) {
WARN_ON_ONCE(resp->rqstp->rq_splice_ok);
if (resp->xdr.buf->page_len && resp->rqstp->rq_splice_ok) {
WARN_ON_ONCE(1);
return nfserr_resource;
}
xdr_commit_encode(xdr);
maxcount = svc_max_payload(resp->rqstp);
if (maxcount > xdr->buf->buflen - xdr->buf->len)
maxcount = xdr->buf->buflen - xdr->buf->len;
if (maxcount > read->rd_length)
maxcount = read->rd_length;