[PATCH 65/71] xfs: check for invalid inode reflink flags

["Darrick J. Wong" <darrick.wong@xxxxxxxxxx>]

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@xxxxxxxxxx>
---
 fs/xfs/libxfs/xfs_inode_buf.c |   16 ++++++++++++++++
 fs/xfs/xfs_ioctl.c            |    4 ++++
 2 files changed, 20 insertions(+)


diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index 2efa42c..9778891 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -386,6 +386,9 @@ xfs_dinode_verify(
        xfs_ino_t               ino,
        struct xfs_dinode       *dip)
 {
+       uint16_t                flags;
+       uint64_t                flags2;
+
        if (dip->di_magic != cpu_to_be16(XFS_DINODE_MAGIC))
                return false;
 
@@ -402,6 +405,19 @@ 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 4d4531ee..c99c7bb 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1035,6 +1035,10 @@ 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.