Merge branch 'merge'

3 files changed, 47 insertions, 40 deletions

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index cc750c6..104a62d 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -128,14 +128,24 @@ void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
 	}
 }
 
-void fuse_remove_background(struct fuse_conn *fc, struct fuse_req *req)
+/*
+ * Called with sbput_sem held for read (request_end) or write
+ * (fuse_put_super).  By the time fuse_put_super() is finished, all
+ * inodes belonging to background requests must be released, so the
+ * iputs have to be done within the locked region.
+ */
+void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req)
 {
-	list_del_init(&req->bg_entry);
+	iput(req->inode);
+	iput(req->inode2);
+	spin_lock(&fc->lock);
+	list_del(&req->bg_entry);
 	if (fc->num_background == FUSE_MAX_BACKGROUND) {
 		fc->blocked = 0;
 		wake_up_all(&fc->blocked_waitq);
 	}
 	fc->num_background--;
+	spin_unlock(&fc->lock);
 }
 
 /*
@@ -165,27 +175,22 @@ static void request_end(struct fuse_conn *fc, struct fuse_req *req)
 		wake_up(&req->waitq);
 		fuse_put_request(fc, req);
 	} else {
-		struct inode *inode = req->inode;
-		struct inode *inode2 = req->inode2;
-		struct file *file = req->file;
 		void (*end) (struct fuse_conn *, struct fuse_req *) = req->end;
 		req->end = NULL;
-		req->inode = NULL;
-		req->inode2 = NULL;
-		req->file = NULL;
-		if (!list_empty(&req->bg_entry))
-			fuse_remove_background(fc, req);
 		spin_unlock(&fc->lock);
+		down_read(&fc->sbput_sem);
+		if (fc->mounted)
+			fuse_release_background(fc, req);
+		up_read(&fc->sbput_sem);
+
+		/* fput must go outside sbput_sem, otherwise it can deadlock */
+		if (req->file)
+			fput(req->file);
 
 		if (end)
 			end(fc, req);
 		else
 			fuse_put_request(fc, req);
-
-		if (file)
-			fput(file);
-		iput(inode);
-		iput(inode2);
 	}
 }
 
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index 59661c4..0474202 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -258,9 +258,15 @@ struct fuse_conn {
 	/** waitq for blocked connection */
 	wait_queue_head_t blocked_waitq;
 
+	/** RW semaphore for exclusion with fuse_put_super() */
+	struct rw_semaphore sbput_sem;
+
 	/** The next unique request id */
 	u64 reqctr;
 
+	/** Mount is active */
+	unsigned mounted;
+
 	/** Connection established, cleared on umount, connection
 	    abort and device release */
 	unsigned connected;
@@ -471,11 +477,11 @@ void request_send_noreply(struct fuse_conn *fc, struct fuse_req *req);
 void request_send_background(struct fuse_conn *fc, struct fuse_req *req);
 
 /**
- * Remove request from the the background list
+ * Release inodes and file associated with background request
  */
-void fuse_remove_background(struct fuse_conn *fc, struct fuse_req *req);
+void fuse_release_background(struct fuse_conn *fc, struct fuse_req *req);
 
-/** Abort all requests */
+/* Abort all requests */
 void fuse_abort_conn(struct fuse_conn *fc);
 
 /**
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 43a6fc0..7627022 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -204,26 +204,17 @@ static void fuse_put_super(struct super_block *sb)
 {
 	struct fuse_conn *fc = get_fuse_conn_super(sb);
 
+	down_write(&fc->sbput_sem);
+	while (!list_empty(&fc->background))
+		fuse_release_background(fc,
+					list_entry(fc->background.next,
+						   struct fuse_req, bg_entry));
+
 	spin_lock(&fc->lock);
+	fc->mounted = 0;
 	fc->connected = 0;
-	while (!list_empty(&fc->background)) {
-		struct fuse_req *req = list_entry(fc->background.next,
-						  struct fuse_req, bg_entry);
-		struct inode *inode = req->inode;
-		struct inode *inode2 = req->inode2;
-
-		/* File would hold a reference to vfsmount */
-		BUG_ON(req->file);
-		req->inode = NULL;
-		req->inode2 = NULL;
-		fuse_remove_background(fc, req);
-
-		spin_unlock(&fc->lock);
-		iput(inode);
-		iput(inode2);
-		spin_lock(&fc->lock);
-	}
 	spin_unlock(&fc->lock);
+	up_write(&fc->sbput_sem);
 	/* Flush all readers on this fs */
 	kill_fasync(&fc->fasync, SIGIO, POLL_IN);
 	wake_up_all(&fc->waitq);
@@ -395,6 +386,7 @@ static struct fuse_conn *new_conn(void)
 		INIT_LIST_HEAD(&fc->processing);
 		INIT_LIST_HEAD(&fc->io);
 		INIT_LIST_HEAD(&fc->background);
+		init_rwsem(&fc->sbput_sem);
 		kobj_set_kset_s(fc, connections_subsys);
 		kobject_init(&fc->kobj);
 		atomic_set(&fc->num_waiting, 0);
@@ -508,11 +500,6 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	if (file->f_op != &fuse_dev_operations)
 		return -EINVAL;
 
-	/* Setting file->private_data can't race with other mount()
-	   instances, since BKL is held for ->get_sb() */
-	if (file->private_data)
-		return -EINVAL;
-
 	fc = new_conn();
 	if (!fc)
 		return -ENOMEM;
@@ -548,7 +535,14 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 	if (err)
 		goto err_free_req;
 
+	/* Setting file->private_data can't race with other mount()
+	   instances, since BKL is held for ->get_sb() */
+	err = -EINVAL;
+	if (file->private_data)
+		goto err_kobject_del;
+
 	sb->s_root = root_dentry;
+	fc->mounted = 1;
 	fc->connected = 1;
 	kobject_get(&fc->kobj);
 	file->private_data = fc;
@@ -563,6 +557,8 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
 
 	return 0;
 
+ err_kobject_del:
+	kobject_del(&fc->kobj);
  err_free_req:
 	fuse_request_free(init_req);
  err_put_root: