ncpfs: rcu-delay unload_nls() and freeing ncp_server

makes ->d_hash() and ->d_compare() safety in RCU mode independent
from vfsmount_lock.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 12 insertions, 7 deletions

diff --git a/fs/ncpfs/inode.c b/fs/ncpfs/inode.c
index 4659da67e7f6..2cf2ebecb55f 100644
--- a/fs/ncpfs/inode.c
+++ b/fs/ncpfs/inode.c
@@ -782,6 +782,17 @@ out:
         return error;
 }
 
+static void delayed_free(struct rcu_head *p)
+{
+        struct ncp_server *server = container_of(p, struct ncp_server, rcu);
+#ifdef CONFIG_NCPFS_NLS
+        /* unload the NLS charsets */
+        unload_nls(server->nls_vol);
+        unload_nls(server->nls_io);
+#endif /* CONFIG_NCPFS_NLS */
+        kfree(server);
+}
+
 static void ncp_put_super(struct super_block *sb)
 {
         struct ncp_server *server = NCP_SBP(sb);
@@ -792,11 +803,6 @@ static void ncp_put_super(struct super_block *sb)
 
         ncp_stop_tasks(server);
 
-#ifdef CONFIG_NCPFS_NLS
-        /* unload the NLS charsets */
-        unload_nls(server->nls_vol);
-        unload_nls(server->nls_io);
-#endif /* CONFIG_NCPFS_NLS */
         mutex_destroy(&server->rcv.creq_mutex);
         mutex_destroy(&server->root_setup_lock);
         mutex_destroy(&server->mutex);
@@ -813,8 +819,7 @@ static void ncp_put_super(struct super_block *sb)
         vfree(server->rxbuf);
         vfree(server->txbuf);
         vfree(server->packet);
-        sb->s_fs_info = NULL;
-        kfree(server);
+        call_rcu(&server->rcu, delayed_free);
 }
 
 static int ncp_statfs(struct dentry *dentry, struct kstatfs *buf)