eCryptfs: Call lower ->flush() from ecryptfs_flush()

Since eCryptfs only calls fput() on the lower file in
ecryptfs_release(), eCryptfs should call the lower filesystem's
->flush() from ecryptfs_flush().

If the lower filesystem implements ->flush(), then eCryptfs should try
to flush out any dirty pages prior to calling the lower ->flush(). If
the lower filesystem does not implement ->flush(), then eCryptfs has no
need to do anything in ecryptfs_flush() since dirty pages are now
written out to the lower filesystem in ecryptfs_release().

Signed-off-by: Tyler Hicks <tyhicks@canonical.com>

diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 44ce5c6a541d65b7ceae1e7d67655a2e3f0f109a..d45ba4568128eb17baf60535d6dc00e663196afa 100644 (file)
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -275,8 +275,14 @@ out:
 
 static int ecryptfs_flush(struct file *file, fl_owner_t td)
 {
-       return file->f_mode & FMODE_WRITE
-              ? filemap_write_and_wait(file->f_mapping) : 0;
+       struct file *lower_file = ecryptfs_file_to_lower(file);
+
+       if (lower_file->f_op && lower_file->f_op->flush) {
+               filemap_write_and_wait(file->f_mapping);
+               return lower_file->f_op->flush(lower_file, td);
+       }
+
+       return 0;
 }
 
 static int ecryptfs_release(struct inode *inode, struct file *file)