NFS/pnfs: Do not clobber existing pgio_done_cb in nfs4_proc_read_setup

If a pNFS client sets hdr->pgio_done_cb, then we should not overwrite that
in nfs4_proc_read_setup()

Fixes: 75bf47ebf6b5 ("pNFS/flexfile: Fix erroneous fall back to...")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index ff416d0e24bc25215a991c282e8ae19a65d31832..6191b7e469133229366f824566d0feb4c4a6155b 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -4392,7 +4392,8 @@ static void nfs4_proc_read_setup(struct nfs_pgio_header *hdr,
                                 struct rpc_message *msg)
 {
        hdr->timestamp   = jiffies;
-       hdr->pgio_done_cb = nfs4_read_done_cb;
+       if (!hdr->pgio_done_cb)
+               hdr->pgio_done_cb = nfs4_read_done_cb;
        msg->rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_READ];
        nfs4_init_sequence(&hdr->args.seq_args, &hdr->res.seq_res, 0);
 }