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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 <bhalevy@tonian.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Benny Halevy 2012-02-23 17:40:52 -08:00 committed by J. Bruce Fields
parent e27f49c33b
commit 508dc6e110
2 changed files with 32 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
fs/nfsd/nfs4state.c
View File

@ -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));

13
fs/nfsd/state.h
View File

@ -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 {