[PATCH] CacheFiles: Handle rename2

[David Howells <dhowells@redhat.com>]

Not all filesystems now provide the rename i_op - ext4 for one - but rather
provide the rename2 i_op.  CacheFiles checks that the filesystem has rename
and so will reject ext4 now with EPERM:

	CacheFiles: Failed to register: -1

Fix this by checking for rename2 as an alternative.  The call to vfs_rename()
actually handles selection of the appropriate function, so we needn't worry
about that.

Turning on debugging shows:

	[cachef] ==> cachefiles_get_directory(,,cache)
	[cachef] subdir -> ffff88000b22b778 positive
	[cachef] <== cachefiles_get_directory() = -1 [check]

where -1 is EPERM.

Signed-off-by: David Howells <dhowells@redhat.com>
---

 fs/cachefiles/namei.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 5bf2b41e66d3..83e9c94ca2cf 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -779,7 +779,8 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 	    !subdir->d_inode->i_op->lookup ||
 	    !subdir->d_inode->i_op->mkdir ||
 	    !subdir->d_inode->i_op->create ||
-	    !subdir->d_inode->i_op->rename ||
+	    (!subdir->d_inode->i_op->rename &&
+	     !subdir->d_inode->i_op->rename2) ||
 	    !subdir->d_inode->i_op->rmdir ||
 	    !subdir->d_inode->i_op->unlink)
 		goto check_error;