ext4: remove the obsolete/broken EXT4_IOC_WAIT_FOR_READONLY ioctl

There are no users of the EXT4_IOC_WAIT_FOR_READONLY ioctl, and it is
also broken.  No one sets the set_ro_timer, no one wakes up us and our
state is set to TASK_INTERRUPTIBLE not RUNNING.  So remove it.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 0 insertions, 28 deletions

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 2046d699b4a7..8f7ea6905421 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -174,29 +174,6 @@ setversion_out:
                 mnt_drop_write(filp->f_path.mnt);
                 return err;
         }
-#ifdef CONFIG_JBD2_DEBUG
-        case EXT4_IOC_WAIT_FOR_READONLY:
-                /*
-                 * This is racy - by the time we're woken up and running,
-                 * the superblock could be released.  And the module could
-                 * have been unloaded.  So sue me.
-                 *
-                 * Returns 1 if it slept, else zero.
-                 */
-                {
-                        DECLARE_WAITQUEUE(wait, current);
-                        int ret = 0;
-
-                        set_current_state(TASK_INTERRUPTIBLE);
-                        add_wait_queue(&EXT4_SB(sb)->ro_wait_queue, &wait);
-                        if (timer_pending(&EXT4_SB(sb)->turn_ro_timer)) {
-                                schedule();
-                                ret = 1;
-                        }
-                        remove_wait_queue(&EXT4_SB(sb)->ro_wait_queue, &wait);
-                        return ret;
-                }
-#endif
         case EXT4_IOC_GROUP_EXTEND: {
                 ext4_fsblk_t n_blocks_count;
                 int err, err2=0;
@@ -421,11 +398,6 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
         case EXT4_IOC32_SETVERSION_OLD:
                 cmd = EXT4_IOC_SETVERSION_OLD;
                 break;
-#ifdef CONFIG_JBD2_DEBUG
-        case EXT4_IOC32_WAIT_FOR_READONLY:
-                cmd = EXT4_IOC_WAIT_FOR_READONLY;
-                break;
-#endif
         case EXT4_IOC32_GETRSVSZ:
                 cmd = EXT4_IOC_GETRSVSZ;
                 break;