[added to the 4.1 stable tree] afs: Flush outstanding writes when an fd is closed

[Sasha Levin <Alexander.Levin@xxxxxxxxxxxxx>]

From: David Howells <dhowells@xxxxxxxxxx>

This patch has been added to the  stable tree. If you have any
objections, please let us know.

===============

[ Upstream commit 58fed94dfb17e89556b5705f20f90e5b2971b6a1 ]

Flush outstanding writes in afs when an fd is closed.  This is what NFS and
CIFS do.

Reported-by: Marc Dionne <marc.c.dionne@xxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 fs/afs/file.c     |  1 +
 fs/afs/internal.h |  1 +
 fs/afs/write.c    | 14 ++++++++++++++
 3 files changed, 16 insertions(+)

diff --git a/fs/afs/file.c b/fs/afs/file.c
index 999bc3caec92..cf8a07e282a6 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -29,6 +29,7 @@ static int afs_readpages(struct file *filp, struct address_space *mapping,
 
 const struct file_operations afs_file_operations = {
 	.open		= afs_open,
+	.flush		= afs_flush,
 	.release	= afs_release,
 	.llseek		= generic_file_llseek,
 	.read_iter	= generic_file_read_iter,
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 71d5982312f3..5cb5c320b966 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -749,6 +749,7 @@ extern int afs_writepages(struct address_space *, struct writeback_control *);
 extern void afs_pages_written_back(struct afs_vnode *, struct afs_call *);
 extern ssize_t afs_file_write(struct kiocb *, struct iov_iter *);
 extern int afs_writeback_all(struct afs_vnode *);
+extern int afs_flush(struct file *, fl_owner_t);
 extern int afs_fsync(struct file *, loff_t, loff_t, int);
 
 
diff --git a/fs/afs/write.c b/fs/afs/write.c
index 777ea2bbf401..cc46e8c1d46e 100644
--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -741,6 +741,20 @@ int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 }
 
 /*
+ * Flush out all outstanding writes on a file opened for writing when it is
+ * closed.
+ */
+int afs_flush(struct file *file, fl_owner_t id)
+{
+	_enter("");
+
+	if ((file->f_mode & FMODE_WRITE) == 0)
+		return 0;
+
+	return vfs_fsync(file, 0);
+}
+
+/*
  * notification that a previously read-only page is about to become writable
  * - if it returns an error, the caller will deliver a bus error signal
  */
-- 
2.11.0