1 files changed, 102 insertions, 44 deletions

diff --git a/fs/file_table.c b/fs/file_table.c
index 7ec0b3e5f05d..e49af4caf15d 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -51,7 +51,9 @@ static void file_free_rcu(struct rcu_head *head)
 
 static inline void file_free(struct file *f)
 {
-	percpu_counter_dec(&nr_files);
+	security_file_free(f);
+	if (!(f->f_mode & FMODE_NOACCOUNT))
+		percpu_counter_dec(&nr_files);
 	call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
 }
 
@@ -90,6 +92,34 @@ int proc_nr_files(struct ctl_table *table, int write,
 }
 #endif
 
+static struct file *__alloc_file(int flags, const struct cred *cred)
+{
+	struct file *f;
+	int error;
+
+	f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
+	if (unlikely(!f))
+		return ERR_PTR(-ENOMEM);
+
+	f->f_cred = get_cred(cred);
+	error = security_file_alloc(f);
+	if (unlikely(error)) {
+		file_free_rcu(&f->f_u.fu_rcuhead);
+		return ERR_PTR(error);
+	}
+
+	atomic_long_set(&f->f_count, 1);
+	rwlock_init(&f->f_owner.lock);
+	spin_lock_init(&f->f_lock);
+	mutex_init(&f->f_pos_lock);
+	eventpoll_init_file(f);
+	f->f_flags = flags;
+	f->f_mode = OPEN_FMODE(flags);
+	/* f->f_version: 0 */
+
+	return f;
+}
+
 /* Find an unused file structure and return a pointer to it.
  * Returns an error pointer if some error happend e.g. we over file
  * structures limit, run out of memory or operation is not permitted.
@@ -100,12 +130,10 @@ int proc_nr_files(struct ctl_table *table, int write,
  * done, you will imbalance int the mount's writer count
  * and a warning at __fput() time.
  */
-struct file *get_empty_filp(void)
+struct file *alloc_empty_file(int flags, const struct cred *cred)
 {
-	const struct cred *cred = current_cred();
 	static long old_max;
 	struct file *f;
-	int error;
 
 	/*
 	 * Privileged users can go above max_files
@@ -119,24 +147,10 @@ struct file *get_empty_filp(void)
 			goto over;
 	}
 
-	f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
-	if (unlikely(!f))
-		return ERR_PTR(-ENOMEM);
-
-	percpu_counter_inc(&nr_files);
-	f->f_cred = get_cred(cred);
-	error = security_file_alloc(f);
-	if (unlikely(error)) {
-		file_free(f);
-		return ERR_PTR(error);
-	}
+	f = __alloc_file(flags, cred);
+	if (!IS_ERR(f))
+		percpu_counter_inc(&nr_files);
 
-	atomic_long_set(&f->f_count, 1);
-	rwlock_init(&f->f_owner.lock);
-	spin_lock_init(&f->f_lock);
-	mutex_init(&f->f_pos_lock);
-	eventpoll_init_file(f);
-	/* f->f_version: 0 */
 	return f;
 
 over:
@@ -148,19 +162,34 @@ over:
 	return ERR_PTR(-ENFILE);
 }
 
+/*
+ * Variant of alloc_empty_file() that doesn't check and modify nr_files.
+ *
+ * Should not be used unless there's a very good reason to do so.
+ */
+struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred)
+{
+	struct file *f = __alloc_file(flags, cred);
+
+	if (!IS_ERR(f))
+		f->f_mode |= FMODE_NOACCOUNT;
+
+	return f;
+}
+
 /**
  * alloc_file - allocate and initialize a 'struct file'
  *
  * @path: the (dentry, vfsmount) pair for the new file
- * @mode: the mode with which the new file will be opened
+ * @flags: O_... flags with which the new file will be opened
  * @fop: the 'struct file_operations' for the new file
  */
-struct file *alloc_file(const struct path *path, fmode_t mode,
+static struct file *alloc_file(const struct path *path, int flags,
 		const struct file_operations *fop)
 {
 	struct file *file;
 
-	file = get_empty_filp();
+	file = alloc_empty_file(flags, current_cred());
 	if (IS_ERR(file))
 		return file;
 
@@ -168,19 +197,56 @@ struct file *alloc_file(const struct path *path, fmode_t mode,
 	file->f_inode = path->dentry->d_inode;
 	file->f_mapping = path->dentry->d_inode->i_mapping;
 	file->f_wb_err = filemap_sample_wb_err(file->f_mapping);
-	if ((mode & FMODE_READ) &&
+	if ((file->f_mode & FMODE_READ) &&
 	     likely(fop->read || fop->read_iter))
-		mode |= FMODE_CAN_READ;
-	if ((mode & FMODE_WRITE) &&
+		file->f_mode |= FMODE_CAN_READ;
+	if ((file->f_mode & FMODE_WRITE) &&
 	     likely(fop->write || fop->write_iter))
-		mode |= FMODE_CAN_WRITE;
-	file->f_mode = mode;
+		file->f_mode |= FMODE_CAN_WRITE;
+	file->f_mode |= FMODE_OPENED;
 	file->f_op = fop;
-	if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
+	if ((file->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
 		i_readcount_inc(path->dentry->d_inode);
 	return file;
 }
-EXPORT_SYMBOL(alloc_file);
+
+struct file *alloc_file_pseudo(struct inode *inode, struct vfsmount *mnt,
+				const char *name, int flags,
+				const struct file_operations *fops)
+{
+	static const struct dentry_operations anon_ops = {
+		.d_dname = simple_dname
+	};
+	struct qstr this = QSTR_INIT(name, strlen(name));
+	struct path path;
+	struct file *file;
+
+	path.dentry = d_alloc_pseudo(mnt->mnt_sb, &this);
+	if (!path.dentry)
+		return ERR_PTR(-ENOMEM);
+	if (!mnt->mnt_sb->s_d_op)
+		d_set_d_op(path.dentry, &anon_ops);
+	path.mnt = mntget(mnt);
+	d_instantiate(path.dentry, inode);
+	file = alloc_file(&path, flags, fops);
+	if (IS_ERR(file)) {
+		ihold(inode);
+		path_put(&path);
+	}
+	return file;
+}
+EXPORT_SYMBOL(alloc_file_pseudo);
+
+struct file *alloc_file_clone(struct file *base, int flags,
+				const struct file_operations *fops)
+{
+	struct file *f = alloc_file(&base->f_path, flags, fops);
+	if (!IS_ERR(f)) {
+		path_get(&f->f_path);
+		f->f_mapping = base->f_mapping;
+	}
+	return f;
+}
 
 /* the real guts of fput() - releasing the last reference to file
  */
@@ -190,6 +256,9 @@ static void __fput(struct file *file)
 	struct vfsmount *mnt = file->f_path.mnt;
 	struct inode *inode = file->f_inode;
 
+	if (unlikely(!(file->f_mode & FMODE_OPENED)))
+		goto out;
+
 	might_sleep();
 
 	fsnotify_close(file);
@@ -207,7 +276,6 @@ static void __fput(struct file *file)
 	}
 	if (file->f_op->release)
 		file->f_op->release(inode, file);
-	security_file_free(file);
 	if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL &&
 		     !(file->f_mode & FMODE_PATH))) {
 		cdev_put(inode->i_cdev);
@@ -220,12 +288,10 @@ static void __fput(struct file *file)
 		put_write_access(inode);
 		__mnt_drop_write(mnt);
 	}
-	file->f_path.dentry = NULL;
-	file->f_path.mnt = NULL;
-	file->f_inode = NULL;
-	file_free(file);
 	dput(dentry);
 	mntput(mnt);
+out:
+	file_free(file);
 }
 
 static LLIST_HEAD(delayed_fput_list);
@@ -300,14 +366,6 @@ void __fput_sync(struct file *file)
 
 EXPORT_SYMBOL(fput);
 
-void put_filp(struct file *file)
-{
-	if (atomic_long_dec_and_test(&file->f_count)) {
-		security_file_free(file);
-		file_free(file);
-	}
-}
-
 void __init files_init(void)
 {
 	filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,