Commit 956fd46f authored by Trond Myklebust's avatar Trond Myklebust Committed by Anna Schumaker
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NFSv4: Fix a state manager thread deadlock regression 



Commit 4dc73c67 reintroduces the deadlock that was fixed by commit
aeabb3c9 ("NFSv4: Fix a NFSv4 state manager deadlock") because it
prevents the setup of new threads to handle reboot recovery, while the
older recovery thread is stuck returning delegations.

Fixes: 4dc73c67 ("NFSv4: keep state manager thread active if swap is enabled")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent ed1cc05a

fs/nfs/nfs4proc.c

+3 −1
Original line number Diff line number Diff line
@@ -10622,7 +10622,9 @@ static void nfs4_disable_swap(struct inode *inode) 
	 */

	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;



	nfs4_schedule_state_manager(clp);

	set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state);

	clear_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state);

	wake_up_var(&clp->cl_state);

}



static const struct inode_operations nfs4_dir_inode_operations = {

fs/nfs/nfs4state.c

+26 −12
Original line number Diff line number Diff line
@@ -1209,16 +1209,26 @@ void nfs4_schedule_state_manager(struct nfs_client *clp) 
{

	struct task_struct *task;

	char buf[INET6_ADDRSTRLEN + sizeof("-manager") + 1];

	struct rpc_clnt *clnt = clp->cl_rpcclient;

	bool swapon = false;



	if (clp->cl_rpcclient->cl_shutdown)

	if (clnt->cl_shutdown)

		return;



	set_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state);

	if (test_and_set_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state) != 0) {



	if (atomic_read(&clnt->cl_swapper)) {

		swapon = !test_and_set_bit(NFS4CLNT_MANAGER_AVAILABLE,

					   &clp->cl_state);

		if (!swapon) {

			wake_up_var(&clp->cl_state);

			return;

		}

	set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state);

	}



	if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0)

		return;



	__module_get(THIS_MODULE);

	refcount_inc(&clp->cl_count);
@@ -1235,8 +1245,9 @@ void nfs4_schedule_state_manager(struct nfs_client *clp) 
			__func__, PTR_ERR(task));

		if (!nfs_client_init_is_complete(clp))

			nfs_mark_client_ready(clp, PTR_ERR(task));

		nfs4_clear_state_manager_bit(clp);

		if (swapon)

			clear_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state);

		nfs4_clear_state_manager_bit(clp);

		nfs_put_client(clp);

		module_put(THIS_MODULE);

	}
@@ -2748,22 +2759,25 @@ static int nfs4_run_state_manager(void *ptr) 


	allow_signal(SIGKILL);

again:

	set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state);

	nfs4_state_manager(clp);

	if (atomic_read(&cl->cl_swapper)) {



	if (test_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state) &&

	    !test_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state)) {

		wait_var_event_interruptible(&clp->cl_state,

					     test_bit(NFS4CLNT_RUN_MANAGER,

						      &clp->cl_state));

		if (atomic_read(&cl->cl_swapper) &&

		    test_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state))

		if (!atomic_read(&cl->cl_swapper))

			clear_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state);

		if (refcount_read(&clp->cl_count) > 1 && !signalled() &&

		    !test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state))

			goto again;

		/* Either no longer a swapper, or were signalled */

	}

		clear_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state);

	}



	if (refcount_read(&clp->cl_count) > 1 && !signalled() &&

	    test_bit(NFS4CLNT_RUN_MANAGER, &clp->cl_state) &&

	    !test_and_set_bit(NFS4CLNT_MANAGER_AVAILABLE, &clp->cl_state))

	    !test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state))

		goto again;



	nfs_put_client(clp);