From b8549877a1e3ca1854fab2527508637b38e63f0d Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Thu, 11 Sep 2014 18:28:47 +0200
Subject: [PATCH] util: storage: Allow metadata crawler to report useful errors

Add a new parameter to virStorageFileGetMetadata that will break the
backing chain detection process and report useful error message rather
than having to use virStorageFileChainGetBroken.

This patch just introduces the option, usage will be provided
separately.
---
 src/qemu/qemu_domain.c        |  3 ++-
 src/security/virt-aa-helper.c |  2 +-
 src/storage/storage_driver.c  | 24 +++++++++++++++++-------
 src/storage/storage_driver.h  |  3 ++-
 tests/virstoragetest.c        |  2 +-
 5 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 5aad7361db..f4b5b8cdfc 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2730,7 +2730,8 @@ qemuDomainDetermineDiskChain(virQEMUDriverPtr driver,
 
     if (virStorageFileGetMetadata(disk->src,
                                   uid, gid,
-                                  cfg->allowDiskFormatProbing) < 0)
+                                  cfg->allowDiskFormatProbing,
+                                  false) < 0)
         ret = -1;
 
  cleanup:
diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa-helper.c
index a06ba4425b..9afc8db15c 100644
--- a/src/security/virt-aa-helper.c
+++ b/src/security/virt-aa-helper.c
@@ -932,7 +932,7 @@ get_files(vahControl * ctl)
          */
         if (!disk->src->backingStore) {
             bool probe = ctl->allowDiskFormatProbing;
-            virStorageFileGetMetadata(disk->src, -1, -1, probe);
+            virStorageFileGetMetadata(disk->src, -1, -1, probe, false);
         }
 
         /* XXX passing ignoreOpenFailure = true to get back to the behavior
diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
index 433d7b723a..c3b29c4916 100644
--- a/src/storage/storage_driver.c
+++ b/src/storage/storage_driver.c
@@ -2783,6 +2783,7 @@ static int
 virStorageFileGetMetadataRecurse(virStorageSourcePtr src,
                                  uid_t uid, gid_t gid,
                                  bool allow_probe,
+                                 bool report_broken,
                                  virHashTablePtr cycle)
 {
     int ret = -1;
@@ -2847,9 +2848,13 @@ virStorageFileGetMetadataRecurse(virStorageSourcePtr src,
     else
         backingStore->format = backingFormat;
 
-    if (virStorageFileGetMetadataRecurse(backingStore,
-                                         uid, gid, allow_probe,
-                                         cycle) < 0) {
+    if ((ret = virStorageFileGetMetadataRecurse(backingStore,
+                                                uid, gid,
+                                                allow_probe, report_broken,
+                                                cycle)) < 0) {
+        if (report_broken)
+            goto cleanup;
+
         /* if we fail somewhere midway, just accept and return a
          * broken chain */
         ret = 0;
@@ -2883,15 +2888,20 @@ virStorageFileGetMetadataRecurse(virStorageSourcePtr src,
  * format, since a malicious guest can turn a raw file into any
  * other non-raw format at will.
  *
+ * If @report_broken is true, the whole function fails with a possibly sane
+ * error instead of just returning a broken chain.
+ *
  * Caller MUST free result after use via virStorageSourceFree.
  */
 int
 virStorageFileGetMetadata(virStorageSourcePtr src,
                           uid_t uid, gid_t gid,
-                          bool allow_probe)
+                          bool allow_probe,
+                          bool report_broken)
 {
-    VIR_DEBUG("path=%s format=%d uid=%d gid=%d probe=%d",
-              src->path, src->format, (int)uid, (int)gid, allow_probe);
+    VIR_DEBUG("path=%s format=%d uid=%d gid=%d probe=%d, report_broken=%d",
+              src->path, src->format, (int)uid, (int)gid,
+              allow_probe, report_broken);
 
     virHashTablePtr cycle = NULL;
     int ret = -1;
@@ -2903,7 +2913,7 @@ virStorageFileGetMetadata(virStorageSourcePtr src,
         src->format = allow_probe ? VIR_STORAGE_FILE_AUTO : VIR_STORAGE_FILE_RAW;
 
     ret = virStorageFileGetMetadataRecurse(src, uid, gid,
-                                           allow_probe, cycle);
+                                           allow_probe, report_broken, cycle);
 
     virHashFree(cycle);
     return ret;
diff --git a/src/storage/storage_driver.h b/src/storage/storage_driver.h
index e77392868b..b805ddd3b5 100644
--- a/src/storage/storage_driver.h
+++ b/src/storage/storage_driver.h
@@ -50,7 +50,8 @@ bool virStorageFileSupportsSecurityDriver(virStorageSourcePtr src);
 
 int virStorageFileGetMetadata(virStorageSourcePtr src,
                               uid_t uid, gid_t gid,
-                              bool allow_probe)
+                              bool allow_probe,
+                              bool report_broken)
     ATTRIBUTE_NONNULL(1);
 
 int virStorageTranslateDiskSourcePool(virConnectPtr conn,
diff --git a/tests/virstoragetest.c b/tests/virstoragetest.c
index e2ee3ff87e..29f5c7a61f 100644
--- a/tests/virstoragetest.c
+++ b/tests/virstoragetest.c
@@ -119,7 +119,7 @@ testStorageFileGetMetadata(const char *path,
     if (VIR_STRDUP(ret->path, path) < 0)
         goto error;
 
-    if (virStorageFileGetMetadata(ret, uid, gid, allow_probe) < 0)
+    if (virStorageFileGetMetadata(ret, uid, gid, allow_probe, false) < 0)
         goto error;
 
     return ret;