From: Chuck Lever Date: Mon, 28 Aug 2023 13:23:00 +0000 (-0400) Subject: SUNRPC: Fix the recent bv_offset fix X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=f16ff1cafbf1e65cc706af912df90bcc15d39a6c;p=linux.git SUNRPC: Fix the recent bv_offset fix Jeff confirmed his original fix addressed his pynfs test failure, but this same bug also impacted qemu: accessing qcow2 virtual disks using direct I/O was failing. Jeff's fix missed that you have to shorten the bio_vec element by the same amount as you increased the page offset. Reported-by: Maxim Levitsky Fixes: c96e2a695e00 ("sunrpc: set the bv_offset of first bvec in svc_tcp_sendmsg") Tested-by: Maxim Levitsky Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever --- diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 2eb8df44f894d..589020ed909dc 100644 --- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -1244,8 +1244,10 @@ static int svc_tcp_sendmsg(struct socket *sock, struct xdr_buf *xdr, if (ret != head->iov_len) goto out; - if (xdr_buf_pagecount(xdr)) + if (xdr_buf_pagecount(xdr)) { xdr->bvec[0].bv_offset = offset_in_page(xdr->page_base); + xdr->bvec[0].bv_len -= offset_in_page(xdr->page_base); + } msg.msg_flags = MSG_SPLICE_PAGES; iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, xdr->bvec,