From eaeaf49524c3b7f26afb86bdeddba8d86bce4790 Mon Sep 17 00:00:00 2001
Message-Id: <eaeaf49524c3b7f26afb86bdeddba8d86bce4790@dist-git>
From: Martin Kletzander <mkletzan@redhat.com>
Date: Wed, 31 Jan 2018 16:32:39 +0100
Subject: [PATCH] util: Don't check if entries under /sys/fs/resctrl/(info/)
 are directories

We are skipping non-directories under /sys/fs/resctrl/(info/) since those are not
interesting for us.  However in tests it can sometimes happen that ent->d_type
is 0 instead of 4 (DT_DIR) for directories.

I've seen it fail on two machines.  Different machines, different systems, I
cannot reproduce it even using the same setup.  So one of the ways how to work
around this is call stat() on it.  The other one is not checking if it is a
directory since we'll find out eventually when we want to read some files
underneath it.

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
(cherry picked from commit f2e16994f7d660a54daba1059441dc0dcf4d9cbd)
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>

https://bugzilla.redhat.com/show_bug.cgi?id=1289368
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
---
 src/util/virresctrl.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/src/util/virresctrl.c b/src/util/virresctrl.c
index 684cb22fd8..42876c6e2b 100644
--- a/src/util/virresctrl.c
+++ b/src/util/virresctrl.c
@@ -410,10 +410,6 @@ virResctrlGetInfo(virResctrlInfoPtr resctrl)
 
     while ((rv = virDirRead(dirp, &ent, SYSFS_RESCTRL_PATH "/info")) > 0) {
         VIR_DEBUG("Parsing info type '%s'", ent->d_name);
-
-        if (ent->d_type != DT_DIR)
-            continue;
-
         if (ent->d_name[0] != 'L')
             continue;
 
@@ -436,19 +432,29 @@ virResctrlGetInfo(virResctrlInfoPtr resctrl)
         rv = virFileReadValueUint(&i_type->control.max_allocation,
                                   SYSFS_RESCTRL_PATH "/info/%s/num_closids",
                                   ent->d_name);
-        if (rv == -2)
-            virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                           _("Cannot get num_closids from resctrl cache info"));
-        if (rv < 0)
+        if (rv == -2) {
+            /* The file doesn't exist, so it's unusable for us,
+             *  but we can scan further */
+            VIR_WARN("The path '" SYSFS_RESCTRL_PATH "/info/%s/num_closids' "
+                     "does not exist",
+                     ent->d_name);
+        } else if (rv < 0) {
+            /* Other failures are fatal, so just quit */
             goto cleanup;
+        }
 
         rv = virFileReadValueString(&i_type->cbm_mask,
                                     SYSFS_RESCTRL_PATH
                                     "/info/%s/cbm_mask",
                                     ent->d_name);
-        if (rv == -2)
+        if (rv == -2) {
+            /* If the previous file exists, so should this one.  Hence -2 is
+             * fatal in this case as well (errors out in next condition) - the
+             * kernel interface might've changed too much or something else is
+             * wrong. */
             virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
                            _("Cannot get cbm_mask from resctrl cache info"));
+        }
         if (rv < 0)
             goto cleanup;
 
@@ -1169,9 +1175,6 @@ virResctrlAllocGetUnused(virResctrlInfoPtr resctrl)
         goto error;
 
     while ((rv = virDirRead(dirp, &ent, SYSFS_RESCTRL_PATH)) > 0) {
-        if (ent->d_type != DT_DIR)
-            continue;
-
         if (STREQ(ent->d_name, "info"))
             continue;
 
-- 
2.16.1