[PATCH 5.4 113/149] NFSv4/pNFS: Dont call _nfs4_pnfs_v3_ds_connect multiple times

Greg Kroah-Hartman
2021-07-19T16:58:11Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit f46f84931a0aa344678efe412d4b071d84d8a805 ]

After we grab the lock in nfs4_pnfs_ds_connect(), there is no check for
whether or not ds->ds_clp has already been initialised, so we can end up
adding the same transports multiple times.

Fixes: fc821d59209d ("pnfs/NFSv4.1: Add multipath capabilities to pNFS flexfiles servers over NFSv3")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/nfs/pnfs_nfs.c | 52 +++++++++++++++++++++++------------------------
1 file changed, 26 insertions(+), 26 deletions(-)

diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index 8b37e7f8e789..249cf9037dbd 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -556,19 +556,16 @@ out:
}
EXPORT_SYMBOL_GPL(nfs4_pnfs_ds_add);

-static void nfs4_wait_ds_connect(struct nfs4_pnfs_ds *ds)
+static int nfs4_wait_ds_connect(struct nfs4_pnfs_ds *ds)
{
might_sleep();
- wait_on_bit(&ds->ds_state, NFS4DS_CONNECTING,
- TASK_KILLABLE);
+ return wait_on_bit(&ds->ds_state, NFS4DS_CONNECTING, TASK_KILLABLE);
}

static void nfs4_clear_ds_conn_bit(struct nfs4_pnfs_ds *ds)
{
smp_mb__before_atomic();
- clear_bit(NFS4DS_CONNECTING, &ds->ds_state);
- smp_mb__after_atomic();
- wake_up_bit(&ds->ds_state, NFS4DS_CONNECTING);
+ clear_and_wake_up_bit(NFS4DS_CONNECTING, &ds->ds_state);
}

static struct nfs_client *(*get_v3_ds_connect)(
@@ -734,30 +731,33 @@ int nfs4_pnfs_ds_connect(struct nfs_server *mds_srv, struct nfs4_pnfs_ds *ds,
{
int err;

-again:
- err = 0;
- if (test_and_set_bit(NFS4DS_CONNECTING, &ds->ds_state) == 0) {
- if (version == 3) {
- err = _nfs4_pnfs_v3_ds_connect(mds_srv, ds, timeo,
- retrans);
- } else if (version == 4) {
- err = _nfs4_pnfs_v4_ds_connect(mds_srv, ds, timeo,
- retrans, minor_version);
- } else {
- dprintk("%s: unsupported DS version %d\n", __func__,
- version);
- err = -EPROTONOSUPPORT;
- }
+ do {
+ err = nfs4_wait_ds_connect(ds);
+ if (err || ds->ds_clp)
+ goto out;
+ if (nfs4_test_deviceid_unavailable(devid))
+ return -ENODEV;
+ } while (test_and_set_bit(NFS4DS_CONNECTING, &ds->ds_state) != 0);

- nfs4_clear_ds_conn_bit(ds);
- } else {
- nfs4_wait_ds_connect(ds);
+ if (ds->ds_clp)
+ goto connect_done;

- /* what was waited on didn't connect AND didn't mark unavail */
- if (!ds->ds_clp && !nfs4_test_deviceid_unavailable(devid))
- goto again;
+ switch (version) {
+ case 3:
+ err = _nfs4_pnfs_v3_ds_connect(mds_srv, ds, timeo, retrans);
+ break;
+ case 4:
+ err = _nfs4_pnfs_v4_ds_connect(mds_srv, ds, timeo, retrans,
+ minor_version);
+ break;
+ default:
+ dprintk("%s: unsupported DS version %d\n", __func__, version);
+ err = -EPROTONOSUPPORT;
}

+connect_done:
+ nfs4_clear_ds_conn_bit(ds);
+out:
/*
* At this point the ds->ds_clp should be ready, but it might have
* hit an error.
--
2.30.2