[PATCH] knfsd: nfsd4: fix corruption on readdir encoding with 64k pages
Fix corruption on readdir encoding with 64k pages.
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 f2710cf..de3998f 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -2157,7 +2157,7 @@
{
int maxcount;
loff_t offset;
- u32 *page, *savep;
+ u32 *page, *savep, *tailbase;
ENCODE_HEAD;
if (nfserr)
@@ -2173,6 +2173,7 @@
WRITE32(0);
ADJUST_ARGS();
resp->xbuf->head[0].iov_len = ((char*)resp->p) - (char*)resp->xbuf->head[0].iov_base;
+ tailbase = p;
maxcount = PAGE_SIZE;
if (maxcount > readdir->rd_maxcount)
@@ -2217,14 +2218,12 @@
*p++ = htonl(readdir->common.err == nfserr_eof);
resp->xbuf->page_len = ((char*)p) - (char*)page_address(resp->rqstp->rq_respages[resp->rqstp->rq_resused-1]);
- /* allocate a page for the tail */
- 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 = tailbase;
resp->xbuf->tail[0].iov_len = 0;
resp->p = resp->xbuf->tail[0].iov_base;
- resp->end = resp->p + PAGE_SIZE/4;
+ resp->end = resp->p + (PAGE_SIZE - resp->xbuf->head[0].iov_len)/4;
return 0;
err_no_verf: