xfs: export the geometry of realtime groups to userspace

Create an ioctl so that the kernel can report the status of realtime
groups to userspace.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 35 insertions, 0 deletions

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 1e233abed7ce..64cf51c8a15d 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -40,6 +40,7 @@
 #include "xfs_file.h"
 #include "xfs_exchrange.h"
 #include "xfs_handle.h"
+#include "xfs_rtgroup.h"
 
 #include <linux/mount.h>
 #include <linux/fileattr.h>
@@ -403,6 +404,38 @@ xfs_ioc_ag_geometry(
 	return 0;
 }
 
+STATIC int
+xfs_ioc_rtgroup_geometry(
+	struct xfs_mount	*mp,
+	void			__user *arg)
+{
+	struct xfs_rtgroup	*rtg;
+	struct xfs_rtgroup_geometry rgeo;
+	int			error;
+
+	if (copy_from_user(&rgeo, arg, sizeof(rgeo)))
+		return -EFAULT;
+	if (rgeo.rg_flags)
+		return -EINVAL;
+	if (memchr_inv(&rgeo.rg_reserved, 0, sizeof(rgeo.rg_reserved)))
+		return -EINVAL;
+	if (!xfs_has_rtgroups(mp))
+		return -EINVAL;
+
+	rtg = xfs_rtgroup_get(mp, rgeo.rg_number);
+	if (!rtg)
+		return -EINVAL;
+
+	error = xfs_rtgroup_get_geometry(rtg, &rgeo);
+	xfs_rtgroup_put(rtg);
+	if (error)
+		return error;
+
+	if (copy_to_user(arg, &rgeo, sizeof(rgeo)))
+		return -EFAULT;
+	return 0;
+}
+
 /*
  * Linux extended inode flags interface.
  */
@@ -1225,6 +1258,8 @@ xfs_file_ioctl(
 
 	case XFS_IOC_AG_GEOMETRY:
 		return xfs_ioc_ag_geometry(mp, arg);
+	case XFS_IOC_RTGROUP_GEOMETRY:
+		return xfs_ioc_rtgroup_geometry(mp, arg);
 
 	case XFS_IOC_GETVERSION:
 		return put_user(inode->i_generation, (int __user *)arg);