Btrfs: Show discard option in /proc/mounts

Christoph's patch e244a0aeb6a599c19a7c802cda6e2d67c847b154 doesn't display
the discard option in /proc/mounts, leading to some confusion for me.
Here's the missing bit.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 193d920e54eb..3f9b45704fcd 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -457,6 +457,8 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
                 seq_puts(seq, ",notreelog");
         if (btrfs_test_opt(root, FLUSHONCOMMIT))
                 seq_puts(seq, ",flushoncommit");
+        if (btrfs_test_opt(root, DISCARD))
+                seq_puts(seq, ",discard");
         if (!(root->fs_info->sb->s_flags & MS_POSIXACL))
                 seq_puts(seq, ",noacl");
         return 0;