From 508dc6e110c6dbdc0bbe84298ccfe22de7538486 Mon Sep 17 00:00:00 2001 From: Benny Halevy Date: Thu, 23 Feb 2012 17:40:52 -0800 Subject: [PATCH] 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: Benny Halevy Signed-off-by: J. Bruce Fields --- fs/nfsd/nfs4state.c | 35 +++++++++++++++++++++++++++++++---- fs/nfsd/state.h | 13 +------------ 2 files changed, 32 insertions(+), 16 deletions(-) diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index 97dd2c75f32..867086357f6 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -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)); diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h index d8f52a0f498..1e2b582bc9d 100644 --- a/fs/nfsd/state.h +++ b/fs/nfsd/state.h @@ -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 { -- 2.39.5