ceph: fix mounting same fs multiple times

Now __ceph_open_session() only accepts closed client. An opened
client will tigger BUG_ON().

Signed-off-by: Yan, Zheng <zyan@redhat.com>

1 files changed, 15 insertions, 18 deletions

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index 715282a92a07..c973043deb0e 100644
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -793,22 +793,20 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc,
         struct dentry *root;
         int first = 0;   /* first vfsmount for this super_block */
 
-        dout("mount start\n");
+        dout("mount start %p\n", fsc);
         mutex_lock(&fsc->client->mount_mutex);
 
-        err = __ceph_open_session(fsc->client, started);
-        if (err < 0)
-                goto out;
+        if (!fsc->sb->s_root) {
+                err = __ceph_open_session(fsc->client, started);
+                if (err < 0)
+                        goto out;
 
-        dout("mount opening root\n");
-        root = open_root_dentry(fsc, "", started);
-        if (IS_ERR(root)) {
-                err = PTR_ERR(root);
-                goto out;
-        }
-        if (fsc->sb->s_root) {
-                dput(root);
-        } else {
+                dout("mount opening root\n");
+                root = open_root_dentry(fsc, "", started);
+                if (IS_ERR(root)) {
+                        err = PTR_ERR(root);
+                        goto out;
+                }
                 fsc->sb->s_root = root;
                 first = 1;
 
@@ -818,6 +816,7 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc,
         }
 
         if (path[0] == 0) {
+                root = fsc->sb->s_root;
                 dget(root);
         } else {
                 dout("mount opening base mountpoint\n");
@@ -833,16 +832,14 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc,
         mutex_unlock(&fsc->client->mount_mutex);
         return root;
 
-out:
-        mutex_unlock(&fsc->client->mount_mutex);
-        return ERR_PTR(err);
-
 fail:
         if (first) {
                 dput(fsc->sb->s_root);
                 fsc->sb->s_root = NULL;
         }
-        goto out;
+out:
+        mutex_unlock(&fsc->client->mount_mutex);
+        return ERR_PTR(err);
 }
 
 static int ceph_set_super(struct super_block *s, void *data)