ext4: don't call fscrypt_get_encryption_info() from dx_show_leaf()

The call to fscrypt_get_encryption_info() in dx_show_leaf() is too low
in the call tree; fscrypt_get_encryption_info() should have already been
called when starting the directory operation.  And indeed, it already
is.  Moreover, the encryption key is guaranteed to already be available
because dx_show_leaf() is only called when adding a new directory entry.

And even if the key wasn't available, dx_show_leaf() uses
fscrypt_fname_disk_to_usr() which knows how to create a no-key name.

So for the above reasons, and because it would be desirable to stop
exporting fscrypt_get_encryption_info() directly to filesystems, remove
the call to fscrypt_get_encryption_info() from dx_show_leaf().
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20201203022041.230976-5-ebiggers@kernel.orgSigned-off-by: NEric Biggers <ebiggers@google.com>

fs/ext4/namei.c

@@ -643,13 +643,7 @@ static struct stats dx_show_leaf(struct inode *dir,
 
 				name  = de->name;
 				len = de->name_len;
-				if (IS_ENCRYPTED(dir))
-					res = fscrypt_get_encryption_info(dir);
-				if (res) {
-					printk(KERN_WARNING "Error setting up"
-					       " fname crypto: %d\n", res);
-				}
-				if (!fscrypt_has_encryption_key(dir)) {
+				if (!IS_ENCRYPTED(dir)) {
 					/* Directory is not encrypted */
 					ext4fs_dirhash(dir, de->name,
 						de->name_len, &h);