[PATCH] knfsd: nfsd4: fix corruption of returned data when using 64k pages
In v4 we grab an extra page just for the padding of returned data. The
formula that the rpc server uses to allocate pages for the response doesn't
take into account this extra page.
Instead of adjusting those formulae, we adopt the same solution as v2 and v3,
and put the "tail" data in the same page as the "head" data.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 845f252..f2710cf 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2084,27 +2084,20 @@
WRITE32(eof);
WRITE32(maxcount);
ADJUST_ARGS();
- resp->xbuf->head[0].iov_len = ((char*)resp->p) - (char*)resp->xbuf->head[0].iov_base;
-
+ resp->xbuf->head[0].iov_len = (char*)p
+ - (char*)resp->xbuf->head[0].iov_base;
resp->xbuf->page_len = maxcount;
- /* read zero bytes -> don't set up tail */
- if(!maxcount)
- return 0;
-
- /* set up page for remaining responses */
- svc_take_page(resp->rqstp);
- resp->xbuf->tail[0].iov_base =
- page_address(resp->rqstp->rq_respages[resp->rqstp->rq_resused-1]);
- resp->rqstp->rq_restailpage = resp->rqstp->rq_resused-1;
+ /* Use rest of head for padding and remaining ops: */
+ resp->rqstp->rq_restailpage = 0;
+ resp->xbuf->tail[0].iov_base = p;
resp->xbuf->tail[0].iov_len = 0;
- resp->p = resp->xbuf->tail[0].iov_base;
- resp->end = resp->p + PAGE_SIZE/4;
-
if (maxcount&3) {
- *(resp->p)++ = 0;
+ RESERVE_SPACE(4);
+ WRITE32(0);
resp->xbuf->tail[0].iov_base += maxcount&3;
resp->xbuf->tail[0].iov_len = 4 - (maxcount&3);
+ ADJUST_ARGS();
}
return 0;
}
@@ -2141,21 +2134,20 @@
WRITE32(maxcount);
ADJUST_ARGS();
- resp->xbuf->head[0].iov_len = ((char*)resp->p) - (char*)resp->xbuf->head[0].iov_base;
-
- svc_take_page(resp->rqstp);
- resp->xbuf->tail[0].iov_base =
- page_address(resp->rqstp->rq_respages[resp->rqstp->rq_resused-1]);
- resp->rqstp->rq_restailpage = resp->rqstp->rq_resused-1;
- resp->xbuf->tail[0].iov_len = 0;
- resp->p = resp->xbuf->tail[0].iov_base;
- resp->end = resp->p + PAGE_SIZE/4;
-
+ resp->xbuf->head[0].iov_len = (char*)p
+ - (char*)resp->xbuf->head[0].iov_base;
resp->xbuf->page_len = maxcount;
+
+ /* Use rest of head for padding and remaining ops: */
+ resp->rqstp->rq_restailpage = 0;
+ resp->xbuf->tail[0].iov_base = p;
+ resp->xbuf->tail[0].iov_len = 0;
if (maxcount&3) {
- *(resp->p)++ = 0;
+ RESERVE_SPACE(4);
+ WRITE32(0);
resp->xbuf->tail[0].iov_base += maxcount&3;
resp->xbuf->tail[0].iov_len = 4 - (maxcount&3);
+ ADJUST_ARGS();
}
return 0;
}