On Mon, Apr 25, 2022 at 08:27:22AM -0700, dai.ngo@xxxxxxxxxx wrote:
> This patch has problem to build with this error:
>
> >>nfsctl.c:(.exit.text+0x0): undefined reference to `laundry_wq'
> >>mipsel-linux-ld: nfsctl.c:(.exit.text+0x4): undefined reference to `laundry_wq'
>
> This happens when CONFIG_NFSD is defined but CONFIG_NFSD_V4
> is not. I think to fix this we need to also move the declaration
> of laundry_wq from nfs4state.c to nfsctl.c. However this seems
> odd since the laundry_wq is only used for v4, unless you have
> any other suggestion.
I'd just leave laundry_wq private to nfs4state.c. Define
create_laundromat() and destroy_laundromat() in nfs4state.c too. And in
nfsd.h, do the usual trick of defining no-op versions of those functions
in the non-v4 case. (See e.g. what we do with nfsd4_init/free_slabs().)
--b.
>
> -Dai
>
> On 4/23/22 11:44 AM, Dai Ngo wrote:
> >This patch moves create/destroy of laundry_wq from nfs4_state_start
> >and nfs4_state_shutdown_net to init_nfsd and exit_nfsd to prevent
> >the laundromat from being freed while a thread is processing a
> >conflicting lock.
> >
> >Signed-off-by: Dai Ngo <dai.ngo@xxxxxxxxxx>
> >---
> > fs/nfsd/nfs4state.c | 15 ++-------------
> > fs/nfsd/nfsctl.c | 6 ++++++
> > fs/nfsd/nfsd.h | 1 +
> > 3 files changed, 9 insertions(+), 13 deletions(-)
> >
> >diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> >index b08c132648b9..b70ba2eb5665 100644
> >--- a/fs/nfsd/nfs4state.c
> >+++ b/fs/nfsd/nfs4state.c
> >@@ -125,7 +125,7 @@ static void free_session(struct nfsd4_session *);
> > static const struct nfsd4_callback_ops nfsd4_cb_recall_ops;
> > static const struct nfsd4_callback_ops nfsd4_cb_notify_lock_ops;
> >-static struct workqueue_struct *laundry_wq;
> >+struct workqueue_struct *laundry_wq;
> > static bool is_session_dead(struct nfsd4_session *ses)
> > {
> >@@ -7798,22 +7798,12 @@ nfs4_state_start(void)
> > {
> > int ret;
> >- laundry_wq = alloc_workqueue("%s", WQ_UNBOUND, 0, "nfsd4");
> >- if (laundry_wq == NULL) {
> >- ret = -ENOMEM;
> >- goto out;
> >- }
> > ret = nfsd4_create_callback_queue();
> > if (ret)
> >- goto out_free_laundry;
> >+ return ret;
> > set_max_delegations();
> > return 0;
> >-
> >-out_free_laundry:
> >- destroy_workqueue(laundry_wq);
> >-out:
> >- return ret;
> > }
> > void
> >@@ -7850,7 +7840,6 @@ nfs4_state_shutdown_net(struct net *net)
> > void
> > nfs4_state_shutdown(void)
> > {
> >- destroy_workqueue(laundry_wq);
> > nfsd4_destroy_callback_queue();
> > }
> >diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> >index 16920e4512bd..884e873b46ad 100644
> >--- a/fs/nfsd/nfsctl.c
> >+++ b/fs/nfsd/nfsctl.c
> >@@ -1544,6 +1544,11 @@ static int __init init_nfsd(void)
> > retval = register_cld_notifier();
> > if (retval)
> > goto out_free_all;
> >+ laundry_wq = alloc_workqueue("%s", WQ_UNBOUND, 0, "nfsd4");
> >+ if (laundry_wq == NULL) {
> >+ retval = -ENOMEM;
> >+ goto out_free_all;
> >+ }
> > return 0;
> > out_free_all:
> > unregister_pernet_subsys(&nfsd_net_ops);
> >@@ -1566,6 +1571,7 @@ static int __init init_nfsd(void)
> > static void __exit exit_nfsd(void)
> > {
> >+ destroy_workqueue(laundry_wq);
> > unregister_cld_notifier();
> > unregister_pernet_subsys(&nfsd_net_ops);
> > nfsd_drc_slab_free();
> >diff --git a/fs/nfsd/nfsd.h b/fs/nfsd/nfsd.h
> >index 23996c6ca75e..d41dcf1c4312 100644
> >--- a/fs/nfsd/nfsd.h
> >+++ b/fs/nfsd/nfsd.h
> >@@ -72,6 +72,7 @@ extern unsigned long nfsd_drc_max_mem;
> > extern unsigned long nfsd_drc_mem_used;
> > extern const struct seq_operations nfs_exports_op;
> >+extern struct workqueue_struct *laundry_wq;
> > /*
> > * Common void argument and result helpers
