From a50730a3f46ffae2e9178a69dda6ac995bbdc154 Mon Sep 17 00:00:00 2001
Message-Id: <a50730a3f46ffae2e9178a69dda6ac995bbdc154@dist-git>
From: Peter Krempa <pkrempa@redhat.com>
Date: Wed, 24 Sep 2014 11:01:27 +0200
Subject: [PATCH] util: storage: Allow metadata crawler to report useful errors

https://bugzilla.redhat.com/show_bug.cgi?id=1138231

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.

(cherry picked from commit b8549877a1e3ca1854fab2527508637b38e63f0d)

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 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 746625a..e471af5 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2734,7 +2734,8 @@ 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 311ce3b..ba542cc 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 433d7b7..c3b29c4 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 e773928..b805ddd 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 e2ee3ff..29f5c7a 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;
-- 
2.1.1