[PATCH 03/41] libxfs: enforce metadata inode flag

["Darrick J. Wong" <djwong@xxxxxxxxxx>]

From: Darrick J. Wong <djwong@xxxxxxxxxx>

Add checks for the metadata inode flag so that we don't ever leak
metadata inodes out to userspace, and we don't ever try to read a
regular inode as metadata.

Signed-off-by: "Darrick J. Wong" <djwong@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
 libxfs/inode.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)


diff --git a/libxfs/inode.c b/libxfs/inode.c
index 1eb0bccae48906..0598a70ff504a4 100644
--- a/libxfs/inode.c
+++ b/libxfs/inode.c
@@ -208,7 +208,8 @@ libxfs_iget(
 /*
  * Get a metadata inode.
  *
- * The metafile type must match the file mode exactly.
+ * The metafile type must match the file mode exactly, and for files in the
+ * metadata directory tree, it must match the inode's metatype exactly.
  */
 int
 libxfs_trans_metafile_iget(
@@ -232,6 +233,12 @@ libxfs_trans_metafile_iget(
 		mode = S_IFREG;
 	if (inode_wrong_type(VFS_I(ip), mode))
 		goto bad_rele;
+	if (xfs_has_metadir(mp)) {
+		if (!xfs_is_metadir_inode(ip))
+			goto bad_rele;
+		if (metafile_type != ip->i_metatype)
+			goto bad_rele;
+	}
 
 	*ipp = ip;
 	return 0;