cifs: clean up cifs_reopen_file

Add a f_flags field that holds the f_flags field from the filp. We'll
need this info in case the filp ever goes away before the cifsFileInfo
does. Have cifs_reopen_file use that value instead of filp->f_flags
too and have it take a cifsFileInfo arg instead of a filp.

While we're at it, get rid of some bogus cargo-cult NULL pointer
checks in that function and reduce the level of indentation.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Suresh Jayaraman <sjayaraman@suse.de>
Acked-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 6c69bd7..b746dec 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -390,6 +390,7 @@
 	/* lock scope id (0 if none) */
 	struct file *pfile; /* needed for writepage */
 	struct dentry *dentry;
+	unsigned int f_flags;
 	struct tcon_link *tlink;
 	struct mutex lock_mutex;
 	struct list_head llist; /* list of byte range locks we have. */