[RFC PATCH 04/79] pipe: add inode field to struct pipe_inode_info

[jglisse@redhat.com]

From: Jérôme Glisse <jglisse@redhat.com>

Pipes are associated with a file and thus an inode, store a pointer
back to the inode in struct pipe_inode_info, this will be use when
testing pages haven't been truncated.

Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-fsdevel@vger.kernel.org
Cc: Tejun Heo <tj@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Josef Bacik <jbacik@fb.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Jeff Layton <jlayton@redhat.com>
---
 fs/pipe.c                 | 2 ++
 fs/splice.c               | 1 +
 include/linux/pipe_fs_i.h | 2 ++
 3 files changed, 5 insertions(+)

diff --git a/fs/pipe.c b/fs/pipe.c
index 7b1954caf388..41e115b0bde7 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -715,6 +715,7 @@ static struct inode * get_pipe_inode(void)
 
 	inode->i_pipe = pipe;
 	pipe->files = 2;
+	pipe->inode = inode;
 	pipe->readers = pipe->writers = 1;
 	inode->i_fop = &pipefifo_fops;
 
@@ -903,6 +904,7 @@ static int fifo_open(struct inode *inode, struct file *filp)
 		pipe = alloc_pipe_info();
 		if (!pipe)
 			return -ENOMEM;
+		pipe->inode = inode;
 		pipe->files = 1;
 		spin_lock(&inode->i_lock);
 		if (unlikely(inode->i_pipe)) {
diff --git a/fs/splice.c b/fs/splice.c
index 39e2dc01ac12..acab52a7fe56 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -927,6 +927,7 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
 		 * PIPE_READERS appropriately.
 		 */
 		pipe->readers = 1;
+		pipe->inode = file_inode(in);
 
 		current->splice_pipe = pipe;
 	}
diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h
index 5a3bb3b7c9ad..171aa78ebbf0 100644
--- a/include/linux/pipe_fs_i.h
+++ b/include/linux/pipe_fs_i.h
@@ -44,6 +44,7 @@ struct pipe_buffer {
  *	@fasync_writers: writer side fasync
  *	@bufs: the circular array of pipe buffers
  *	@user: the user who created this pipe
+ *	@inode: inode this pipe is associated to
  **/
 struct pipe_inode_info {
 	struct mutex mutex;
@@ -60,6 +61,7 @@ struct pipe_inode_info {
 	struct fasync_struct *fasync_writers;
 	struct pipe_buffer *bufs;
 	struct user_struct *user;
+	struct inode *inode;
 };
 
 /*
-- 
2.14.3