cifs: add a deprecation warning to CIFS_IOC_CHECKUMOUNT ioctl

This was used by an ancient version of umount.cifs and in nowhere else
that I'm aware of. Let's add a warning now and dump it for 3.7.

Signed-off-by: Jeff Layton <jlayton@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/fs/cifs/ioctl.c b/fs/cifs/ioctl.c
index 4221b5e48a42..6d2667f0c98c 100644
--- a/fs/cifs/ioctl.c
+++ b/fs/cifs/ioctl.c
@@ -51,7 +51,15 @@ long cifs_ioctl(struct file *filep, unsigned int command, unsigned long arg)
         cifs_sb = CIFS_SB(inode->i_sb);
 
         switch (command) {
+                static bool warned = false;
                 case CIFS_IOC_CHECKUMOUNT:
+                        if (!warned) {
+                                warned = true;
+                                cERROR(1, "the CIFS_IOC_CHECKMOUNT ioctl will "
+                                          "be deprecated in 3.7. Please "
+                                          "migrate away from the use of "
+                                          "umount.cifs");
+                        }
                         cFYI(1, "User unmount attempted");
                         if (cifs_sb->mnt_uid == current_uid())
                                 rc = 0;