1 files changed, 41 insertions, 6 deletions

diff --git a/fs/file.c b/fs/file.c
index 7ffd6e9d103d..3da91a112bab 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -158,7 +158,7 @@ static int expand_fdtable(struct files_struct *files, unsigned int nr)
 	 * or have finished their rcu_read_lock_sched() section.
 	 */
 	if (atomic_read(&files->count) > 1)
-		synchronize_sched();
+		synchronize_rcu();
 
 	spin_lock(&files->file_lock);
 	if (!new_fdt)
@@ -457,6 +457,7 @@ struct files_struct init_files = {
 		.full_fds_bits	= init_files.full_fds_bits_init,
 	},
 	.file_lock	= __SPIN_LOCK_UNLOCKED(init_files.file_lock),
+	.resize_wait	= __WAIT_QUEUE_HEAD_INITIALIZER(init_files.resize_wait),
 };
 
 static unsigned int find_next_fd(struct fdtable *fdt, unsigned int start)
@@ -640,6 +641,35 @@ out_unlock:
 }
 EXPORT_SYMBOL(__close_fd); /* for ksys_close() */
 
+/*
+ * variant of __close_fd that gets a ref on the file for later fput
+ */
+int __close_fd_get_file(unsigned int fd, struct file **res)
+{
+	struct files_struct *files = current->files;
+	struct file *file;
+	struct fdtable *fdt;
+
+	spin_lock(&files->file_lock);
+	fdt = files_fdtable(files);
+	if (fd >= fdt->max_fds)
+		goto out_unlock;
+	file = fdt->fd[fd];
+	if (!file)
+		goto out_unlock;
+	rcu_assign_pointer(fdt->fd[fd], NULL);
+	__put_unused_fd(files, fd);
+	spin_unlock(&files->file_lock);
+	get_file(file);
+	*res = file;
+	return filp_close(file, files);
+
+out_unlock:
+	spin_unlock(&files->file_lock);
+	*res = NULL;
+	return -ENOENT;
+}
+
 void do_close_on_exec(struct files_struct *files)
 {
 	unsigned i;
@@ -676,7 +706,7 @@ void do_close_on_exec(struct files_struct *files)
 	spin_unlock(&files->file_lock);
 }
 
-static struct file *__fget(unsigned int fd, fmode_t mask)
+static struct file *__fget(unsigned int fd, fmode_t mask, unsigned int refs)
 {
 	struct files_struct *files = current->files;
 	struct file *file;
@@ -691,7 +721,7 @@ loop:
 		 */
 		if (file->f_mode & mask)
 			file = NULL;
-		else if (!get_file_rcu(file))
+		else if (!get_file_rcu_many(file, refs))
 			goto loop;
 	}
 	rcu_read_unlock();
@@ -699,15 +729,20 @@ loop:
 	return file;
 }
 
+struct file *fget_many(unsigned int fd, unsigned int refs)
+{
+	return __fget(fd, FMODE_PATH, refs);
+}
+
 struct file *fget(unsigned int fd)
 {
-	return __fget(fd, FMODE_PATH);
+	return __fget(fd, FMODE_PATH, 1);
 }
 EXPORT_SYMBOL(fget);
 
 struct file *fget_raw(unsigned int fd)
 {
-	return __fget(fd, 0);
+	return __fget(fd, 0, 1);
 }
 EXPORT_SYMBOL(fget_raw);
 
@@ -738,7 +773,7 @@ static unsigned long __fget_light(unsigned int fd, fmode_t mask)
 			return 0;
 		return (unsigned long)file;
 	} else {
-		file = __fget(fd, mask);
+		file = __fget(fd, mask, 1);
 		if (!file)
 			return 0;
 		return FDPUT_FPUT | (unsigned long)file;