From: Chuck Lever <chuck.lever@xxxxxxxxxx>
[ Upstream commit 6c254bf3b637dd4ef4f78eb78c7447419c0161d7 ]
I found that NFSD's new NFSv3 READDIRPLUS XDR encoder was screwing up
right at the end of the page array. xdr_get_next_encode_buffer() does
not compute the value of xdr->end correctly:
* The check to see if we're on the final available page in xdr->buf
needs to account for the space consumed by @nbytes.
* The new xdr->end value needs to account for the portion of @nbytes
that is to be encoded into the previous buffer.
Fixes: 2825a7f90753 ("nfsd4: allow encoding across page boundaries")
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Reviewed-by: NeilBrown <neilb@xxxxxxx>
Reviewed-by: J. Bruce Fields <bfields@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/sunrpc/xdr.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 540e340e2565..34596d0e4bde 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -544,7 +544,11 @@ static __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr,
*/
xdr->p = (void *)p + frag2bytes;
space_left = xdr->buf->buflen - xdr->buf->len;
- xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE);
+ if (space_left - nbytes >= PAGE_SIZE)
+ xdr->end = (void *)p + PAGE_SIZE;
+ else
+ xdr->end = (void *)p + space_left - frag1bytes;
+
xdr->buf->page_len += frag2bytes;
xdr->buf->len += nbytes;
return p;
--
2.35.1
