If kthread_run fails we put the client and delegation. This requires
the state lock since the fi_hash is manipulated in the process.
Use nfs4_lock_state_nested as nfsd_break_deleg_cb may be called
back by the filesystem while under the state lock (e.g. in the close path)
Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 17 +++++++++++++++++
1 files changed, 17 insertions(+), 0 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 7fe074a..0b45680 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -94,6 +94,7 @@ static void nfs4_set_recdir(char *recdir);
* unconfstr_hashtbl[], uncofid_hashtbl[].
*/
static DEFINE_MUTEX(client_mutex);
+static struct thread_info *client_mutex_owner;
static struct kmem_cache *stateowner_slab = NULL;
static struct kmem_cache *file_slab = NULL;
@@ -106,14 +107,26 @@ void
nfs4_lock_state(void)
{
mutex_lock(&client_mutex);
+ client_mutex_owner = current_thread_info();
}
void
nfs4_unlock_state(void)
{
+ BUG_ON(client_mutex_owner != current_thread_info());
+ client_mutex_owner = NULL;
mutex_unlock(&client_mutex);
}
+static int
+nfs4_lock_state_nested(void)
+{
+ if (client_mutex_owner == current_thread_info())
+ return 0;
+ nfs4_lock_state();
+ return 1;
+}
+
static inline u32
opaque_hashval(const void *ptr, int nbytes)
{
@@ -1798,6 +1811,7 @@ void nfsd_break_deleg_cb(struct file_lock *fl)
{
struct nfs4_delegation *dp= (struct nfs4_delegation *)fl->fl_owner;
struct task_struct *t;
+ int did_lock;
dprintk("NFSD nfsd_break_deleg_cb: dp %p fl %p\n",dp,fl);
if (!dp)
@@ -1832,8 +1846,11 @@ void nfsd_break_deleg_cb(struct file_lock *fl)
printk(KERN_INFO "NFSD: Callback thread failed for "
"for client (clientid %08x/%08x)\n",
clp->cl_clientid.cl_boot, clp->cl_clientid.cl_id);
+ did_lock = nfs4_lock_state_nested();
put_nfs4_client(dp->dl_client);
nfs4_put_delegation(dp);
+ if (did_lock)
+ nfs4_unlock_state();
}
}
--
1.6.0.2
--
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