aio: hold an extra file reference over AIO read/write operations

Otherwise we might dereference an already freed file and/or inode
when aio_complete is called before we return from the read_iter or
write_iter method.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
(cherry picked from commit 0b944d3a4bba6b25f43aed530f4fa85c04d162a6)
Change-Id: I628a87b5036ba1ba5ba5152fa0329d02999d3649
Git-Commit: 0b944d3a4bba6b25f43aed530f4fa85c04d162a6
Git-Repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
[riteshh@codeaurora.org: resolve trivial merge conflicts]
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/aio.c b/fs/aio.c
index c4b508605bab..3fe07571f942 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1470,6 +1470,7 @@ rw_common:
 
 		len = ret;
 
+		get_file(file);
 		if (rw == WRITE)
 			file_start_write(file);
 
@@ -1477,6 +1478,7 @@ rw_common:
 
 		if (rw == WRITE)
 			file_end_write(file);
+		fput(file);
 		kfree(iovec);
 		break;