Commit 7b012732 authored by Alexander Aring's avatar Alexander Aring Committed by David Teigland
Browse files

dlm: fix sleep in atomic context 



This patch changes the orphans mutex to a spinlock since commit
c288745f ("dlm: avoid blocking receive at the end of recovery") is
using a rwlock_t to lock the DLM message receive path and do_purge() can
be called while this lock is held that forbids to sleep.

We need to use spin_lock_bh() because also a user context that calls
dlm_user_purge() can call do_purge() and since commit 92d59adf
("dlm: do message processing in softirq context") the DLM message
receive path is done under softirq context.

Fixes: c288745f ("dlm: avoid blocking receive at the end of recovery")
Reported-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/gfs2/9ad928eb-2ece-4ad9-a79c-d2bce228e4bc@moroto.mountain/


Signed-off-by: default avatarAlexander Aring <aahringo@redhat.com>
Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
parent 15fd7e55

fs/dlm/dlm_internal.h

+1 −1
Original line number Diff line number Diff line
@@ -602,7 +602,7 @@ struct dlm_ls { 
	spinlock_t		ls_waiters_lock;

	struct list_head	ls_waiters;	/* lkbs needing a reply */



	struct mutex		ls_orphans_mutex;

	spinlock_t		ls_orphans_lock;

	struct list_head	ls_orphans;



	spinlock_t		ls_new_rsb_spin;

fs/dlm/lock.c

+6 −6
Original line number Diff line number Diff line
@@ -5880,7 +5880,7 @@ int dlm_user_adopt_orphan(struct dlm_ls *ls, struct dlm_user_args *ua_tmp, 
	int found_other_mode = 0;

	int rv = 0;



	mutex_lock(&ls->ls_orphans_mutex);

	spin_lock_bh(&ls->ls_orphans_lock);

	list_for_each_entry(iter, &ls->ls_orphans, lkb_ownqueue) {

		if (iter->lkb_resource->res_length != namelen)

			continue;
@@ -5897,7 +5897,7 @@ int dlm_user_adopt_orphan(struct dlm_ls *ls, struct dlm_user_args *ua_tmp, 
		*lkid = iter->lkb_id;

		break;

	}

	mutex_unlock(&ls->ls_orphans_mutex);

	spin_unlock_bh(&ls->ls_orphans_lock);



	if (!lkb && found_other_mode) {

		rv = -EAGAIN;
@@ -6089,9 +6089,9 @@ static int orphan_proc_lock(struct dlm_ls *ls, struct dlm_lkb *lkb) 
	int error;



	hold_lkb(lkb); /* reference for the ls_orphans list */

	mutex_lock(&ls->ls_orphans_mutex);

	spin_lock_bh(&ls->ls_orphans_lock);

	list_add_tail(&lkb->lkb_ownqueue, &ls->ls_orphans);

	mutex_unlock(&ls->ls_orphans_mutex);

	spin_unlock_bh(&ls->ls_orphans_lock);



	set_unlock_args(0, lkb->lkb_ua, &args);
@@ -6241,7 +6241,7 @@ static void do_purge(struct dlm_ls *ls, int nodeid, int pid) 
{

	struct dlm_lkb *lkb, *safe;



	mutex_lock(&ls->ls_orphans_mutex);

	spin_lock_bh(&ls->ls_orphans_lock);

	list_for_each_entry_safe(lkb, safe, &ls->ls_orphans, lkb_ownqueue) {

		if (pid && lkb->lkb_ownpid != pid)

			continue;
@@ -6249,7 +6249,7 @@ static void do_purge(struct dlm_ls *ls, int nodeid, int pid) 
		list_del_init(&lkb->lkb_ownqueue);

		dlm_put_lkb(lkb);

	}

	mutex_unlock(&ls->ls_orphans_mutex);

	spin_unlock_bh(&ls->ls_orphans_lock);

}



static int send_purge(struct dlm_ls *ls, int nodeid, int pid)

fs/dlm/lockspace.c

+1 −1
Original line number Diff line number Diff line
@@ -436,7 +436,7 @@ static int new_lockspace(const char *name, const char *cluster, 
	INIT_LIST_HEAD(&ls->ls_waiters);

	spin_lock_init(&ls->ls_waiters_lock);

	INIT_LIST_HEAD(&ls->ls_orphans);

	mutex_init(&ls->ls_orphans_mutex);

	spin_lock_init(&ls->ls_orphans_lock);



	INIT_LIST_HEAD(&ls->ls_new_rsb);

	spin_lock_init(&ls->ls_new_rsb_spin);