From: Chuck Lever chuck.lever@oracle.com
[ 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@oracle.com Reviewed-by: NeilBrown neilb@suse.de Reviewed-by: J. Bruce Fields bfields@fieldses.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 87cf0b933f99..51ccde7c1311 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;