orangefs: free superblock when mount fails

commit 1ec1688c5360e14dde4094d6acbf7516bf6db37e upstream.

Otherwise lockdep says:

[ 1337.483798] ================================================
[ 1337.483999] [ BUG: lock held when returning to user space! ]
[ 1337.484252] 4.11.0-rc6 #19 Not tainted
[ 1337.484423] ------------------------------------------------
[ 1337.484626] mount/14766 is leaving the kernel with locks still held!
[ 1337.484841] 1 lock held by mount/14766:
[ 1337.485017]  #0:  (&type->s_umount_key#33/1){+.+.+.}, at: [<ffffffff8124171f>] sget_userns+0x2af/0x520

Caught by xfstests generic/413 which tried to mount with the unsupported
mount option dax.  Then xfstests generic/422 ran sync which deadlocks.

Signed-off-by: Martin Brandenburg <martin@omnibond.com>
Acked-by: Mike Marshall <hubcap@omnibond.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 24 insertions, 9 deletions

diff --git a/fs/orangefs/devorangefs-req.c b/fs/orangefs/devorangefs-req.c
index f419dd999581..fe2cbeb90772 100644
--- a/fs/orangefs/devorangefs-req.c
+++ b/fs/orangefs/devorangefs-req.c
@@ -208,14 +208,19 @@ restart:
                                 continue;
                         /*
                          * Skip ops whose filesystem we don't know about unless
-                         * it is being mounted.
+                         * it is being mounted or unmounted.  It is possible for
+                         * a filesystem we don't know about to be unmounted if
+                         * it fails to mount in the kernel after userspace has
+                         * been sent the mount request.
                          */
                         /* XXX: is there a better way to detect this? */
                         } else if (ret == -1 &&
                                    !(op->upcall.type ==
                                         ORANGEFS_VFS_OP_FS_MOUNT ||
                                      op->upcall.type ==
-                                        ORANGEFS_VFS_OP_GETATTR)) {
+                                        ORANGEFS_VFS_OP_GETATTR ||
+                                     op->upcall.type ==
+                                        ORANGEFS_VFS_OP_FS_UMOUNT)) {
                                 gossip_debug(GOSSIP_DEV_DEBUG,
                                     "orangefs: skipping op tag %llu %s\n",
                                     llu(op->tag), get_opname_string(op));
diff --git a/fs/orangefs/orangefs-kernel.h b/fs/orangefs/orangefs-kernel.h
index 3bf803d732c5..45dd8f27b2ac 100644
--- a/fs/orangefs/orangefs-kernel.h
+++ b/fs/orangefs/orangefs-kernel.h
@@ -249,6 +249,7 @@ struct orangefs_sb_info_s {
         char devname[ORANGEFS_MAX_SERVER_ADDR_LEN];
         struct super_block *sb;
         int mount_pending;
+        int no_list;
         struct list_head list;
 };
 
diff --git a/fs/orangefs/super.c b/fs/orangefs/super.c
index cd261c8de53a..629d8c917fa6 100644
--- a/fs/orangefs/super.c
+++ b/fs/orangefs/super.c
@@ -493,7 +493,7 @@ struct dentry *orangefs_mount(struct file_system_type *fst,
 
         if (ret) {
                 d = ERR_PTR(ret);
-                goto free_op;
+                goto free_sb_and_op;
         }
 
         /*
@@ -519,6 +519,9 @@ struct dentry *orangefs_mount(struct file_system_type *fst,
         spin_unlock(&orangefs_superblocks_lock);
         op_release(new_op);
 
+        /* Must be removed from the list now. */
+        ORANGEFS_SB(sb)->no_list = 0;
+
         if (orangefs_userspace_version >= 20906) {
                 new_op = op_alloc(ORANGEFS_VFS_OP_FEATURES);
                 if (!new_op)
@@ -533,6 +536,10 @@ struct dentry *orangefs_mount(struct file_system_type *fst,
 
         return dget(sb->s_root);
 
+free_sb_and_op:
+        /* Will call orangefs_kill_sb with sb not in list. */
+        ORANGEFS_SB(sb)->no_list = 1;
+        deactivate_locked_super(sb);
 free_op:
         gossip_err("orangefs_mount: mount request failed with %d\n", ret);
         if (ret == -EINVAL) {
@@ -558,12 +565,14 @@ void orangefs_kill_sb(struct super_block *sb)
          */
          orangefs_unmount_sb(sb);
 
-        /* remove the sb from our list of orangefs specific sb's */
-
-        spin_lock(&orangefs_superblocks_lock);
-        __list_del_entry(&ORANGEFS_SB(sb)->list);       /* not list_del_init */
-        ORANGEFS_SB(sb)->list.prev = NULL;
-        spin_unlock(&orangefs_superblocks_lock);
+        if (!ORANGEFS_SB(sb)->no_list) {
+                /* remove the sb from our list of orangefs specific sb's */
+                spin_lock(&orangefs_superblocks_lock);
+                /* not list_del_init */
+                __list_del_entry(&ORANGEFS_SB(sb)->list);
+                ORANGEFS_SB(sb)->list.prev = NULL;
+                spin_unlock(&orangefs_superblocks_lock);
+        }
 
         /*
          * make sure that ORANGEFS_DEV_REMOUNT_ALL loop that might've seen us