Commit 508dc6e1 authored by Benny Halevy's avatar Benny Halevy Committed by J. Bruce Fields
Browse files

nfsd41: free_session/free_client must be called under the client_lock 



The session client is manipulated under the client_lock hence
both free_session and nfsd4_del_conns must be called under this lock.

This patch adds a BUG_ON that checks this condition in the
respective functions and implements the missing locks.

nfsd4_{get,put}_session helpers were moved to the C file that uses them
so to prevent use from external files and an unlocked version of
nfsd4_put_session is provided for external use from nfs4xdr.c

Signed-off-by: default avatarBenny Halevy <bhalevy@tonian.com>
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent e27f49c3

fs/nfsd/nfs4state.c

+31 −4
Original line number Diff line number Diff line
@@ -95,6 +95,19 @@ nfs4_lock_state(void) 
	mutex_lock(&client_mutex);

}



static void free_session(struct kref *);



/* Must be called under the client_lock */

static void nfsd4_put_session_locked(struct nfsd4_session *ses)

{

	kref_put(&ses->se_ref, free_session);

}



static void nfsd4_get_session(struct nfsd4_session *ses)

{

	kref_get(&ses->se_ref);

}



void

nfs4_unlock_state(void)

{
@@ -836,11 +849,12 @@ static void nfsd4_del_conns(struct nfsd4_session *s) 
	spin_unlock(&clp->cl_lock);

}



void free_session(struct kref *kref)

static void free_session(struct kref *kref)

{

	struct nfsd4_session *ses;

	int mem;



	BUG_ON(!spin_is_locked(&client_lock));

	ses = container_of(kref, struct nfsd4_session, se_ref);

	nfsd4_del_conns(ses);

	spin_lock(&nfsd_drc_lock);
@@ -851,6 +865,13 @@ void free_session(struct kref *kref) 
	kfree(ses);

}



void nfsd4_put_session(struct nfsd4_session *ses)

{

	spin_lock(&client_lock);

	nfsd4_put_session_locked(ses);

	spin_unlock(&client_lock);

}



static struct nfsd4_session *alloc_init_session(struct svc_rqst *rqstp, struct nfs4_client *clp, struct nfsd4_create_session *cses)

{

	struct nfsd4_session *new;
@@ -898,7 +919,9 @@ static struct nfsd4_session *alloc_init_session(struct svc_rqst *rqstp, struct n 
	status = nfsd4_new_conn_from_crses(rqstp, new);

	/* whoops: benny points out, status is ignored! (err, or bogus) */

	if (status) {

		spin_lock(&client_lock);

		free_session(&new->se_ref);

		spin_unlock(&client_lock);

		return NULL;

	}

	if (cses->flags & SESSION4_BACK_CHAN) {
@@ -1010,12 +1033,13 @@ static struct nfs4_client *alloc_client(struct xdr_netobj name) 
static inline void

free_client(struct nfs4_client *clp)

{

	BUG_ON(!spin_is_locked(&client_lock));

	while (!list_empty(&clp->cl_sessions)) {

		struct nfsd4_session *ses;

		ses = list_entry(clp->cl_sessions.next, struct nfsd4_session,

				se_perclnt);

		list_del(&ses->se_perclnt);

		nfsd4_put_session(ses);

		nfsd4_put_session_locked(ses);

	}

	if (clp->cl_cred.cr_group_info)

		put_group_info(clp->cl_cred.cr_group_info);
@@ -1184,7 +1208,9 @@ static struct nfs4_client *create_client(struct xdr_netobj name, char *recdir, 
	if (princ) {

		clp->cl_principal = kstrdup(princ, GFP_KERNEL);

		if (clp->cl_principal == NULL) {

			spin_lock(&client_lock);

			free_client(clp);

			spin_unlock(&client_lock);

			return NULL;

		}

	}
@@ -1812,9 +1838,10 @@ nfsd4_destroy_session(struct svc_rqst *r, 
	nfsd4_probe_callback_sync(ses->se_client);

	nfs4_unlock_state();



	spin_lock(&client_lock);

	nfsd4_del_conns(ses);



	nfsd4_put_session(ses);

	nfsd4_put_session_locked(ses);

	spin_unlock(&client_lock);

	status = nfs_ok;

out:

	dprintk("%s returns %d\n", __func__, ntohl(status));

fs/nfsd/state.h

+1 −12
Original line number Diff line number Diff line
@@ -198,18 +198,7 @@ struct nfsd4_session { 
	struct nfsd4_slot	*se_slots[];	/* forward channel slots */

};



static inline void

nfsd4_put_session(struct nfsd4_session *ses)

{

	extern void free_session(struct kref *kref);

	kref_put(&ses->se_ref, free_session);

}



static inline void

nfsd4_get_session(struct nfsd4_session *ses)

{

	kref_get(&ses->se_ref);

}

extern void nfsd4_put_session(struct nfsd4_session *ses);



/* formatted contents of nfs4_sessionid */

struct nfsd4_sessionid {

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