xfs: check for invalid inode reflink flags

We don't support sharing blocks on the realtime device.  Flag inodes
with the reflink or cowextsize flags set when the reflink feature is
disabled.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

2 files changed, 20 insertions, 0 deletions

diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index a3e803823a19..f1b9d97c540f 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -375,6 +375,9 @@ xfs_dinode_verify(
         struct xfs_inode        *ip,
         struct xfs_dinode       *dip)
 {
+        uint16_t                flags;
+        uint64_t                flags2;
+
         if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC))
                 return false;
 
@@ -391,6 +394,19 @@ xfs_dinode_verify(
                 return false;
         if (!uuid_equal(&dip->di_uuid, &mp->m_sb.sb_meta_uuid))
                 return false;
+
+        flags = be16_to_cpu(dip->di_flags);
+        flags2 = be64_to_cpu(dip->di_flags2);
+
+        /* don't allow reflink/cowextsize if we don't have reflink */
+        if ((flags2 & (XFS_DIFLAG2_REFLINK | XFS_DIFLAG2_COWEXTSIZE)) &&
+            !xfs_sb_version_hasreflink(&mp->m_sb))
+                return false;
+
+        /* don't let reflink and realtime mix */
+        if ((flags2 & XFS_DIFLAG2_REFLINK) && (flags & XFS_DIFLAG_REALTIME))
+                return false;
+
         return true;
 }
 
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 1388a1275dc8..c65d9eacf54d 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1034,6 +1034,10 @@ xfs_ioctl_setattr_xflags(
                         return -EINVAL;
         }
 
+        /* Don't allow us to set realtime mode for a reflinked file. */
+        if ((fa->fsx_xflags & FS_XFLAG_REALTIME) && xfs_is_reflink_inode(ip))
+                return -EINVAL;
+
         /*
          * Can't modify an immutable/append-only file unless
          * we have appropriate permission.