xfs: Fix x32 ioctls when cmd numbers differ from ia32.

Several ioctl structs change size between native 32-bit (ia32) and x32
applications, because x32 follows the native 64-bit (amd64) integer
alignment rules and uses 64-bit time_t.  In these instances, the ioctl
number changes so userspace simply gets -ENOTTY.  This scenario can be
handled by simply adding more cases.

Looking at the different ioctls implemented here:

- All the ones marked 'No size or alignment issue on any arch' should
  presumably all be fine.

- All the ones under BROKEN_X86_ALIGNMENT are different under integer
  alignment rules.  Since x32 matches amd64 here, we just need both
  sets of cases handled.

- XFS_IOC_SWAPEXT has both integer alignment differences and time_t
  differences.  Since x32 matches amd64 here, we need to add a case
  which calls the native implementation.

- The remaining ioctls have neither 64-bit integers nor time_t, so
  x32 matches ia32 here and no change is required at this level.  The
  bulkstat ioctl implementations have some pointer chasing which is
  handled separately.
Signed-off-by: Nick Bowler <nbowler@draconx.ca>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/xfs_ioctl32.c

@@ -579,8 +579,12 @@ xfs_file_compat_ioctl(
 	case FS_IOC_GETFSMAP:
 	case XFS_IOC_SCRUB_METADATA:
 		return xfs_file_ioctl(filp, cmd, p);
-#ifndef BROKEN_X86_ALIGNMENT
-	/* These are handled fine if no alignment issues */
+#if !defined(BROKEN_X86_ALIGNMENT) || defined(CONFIG_X86_X32)
+	/*
+	 * These are handled fine if no alignment issues.  To support x32
+	 * which uses native 64-bit alignment we must emit these cases in
+	 * addition to the ia-32 compat set below.
+	 */
 	case XFS_IOC_ALLOCSP:
 	case XFS_IOC_FREESP:
 	case XFS_IOC_RESVSP:
@@ -593,8 +597,16 @@ xfs_file_compat_ioctl(
 	case XFS_IOC_FSGROWFSDATA:
 	case XFS_IOC_FSGROWFSRT:
 	case XFS_IOC_ZERO_RANGE:
+#ifdef CONFIG_X86_X32
+	/*
+	 * x32 special: this gets a different cmd number from the ia-32 compat
+	 * case below; the associated data will match native 64-bit alignment.
+	 */
+	case XFS_IOC_SWAPEXT:
+#endif
 		return xfs_file_ioctl(filp, cmd, p);
-#else
+#endif
+#if defined(BROKEN_X86_ALIGNMENT)
 	case XFS_IOC_ALLOCSP_32:
 	case XFS_IOC_FREESP_32:
 	case XFS_IOC_ALLOCSP64_32: