Blame SOURCES/libvirt-storage-Add-helper-to-retrieve-the-backing-store-string-of-a-storage-volume.patch

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From a4d89750b7d61aa561b9b9956bf354e39f434b01 Mon Sep 17 00:00:00 2001
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Message-Id: <a4d89750b7d61aa561b9b9956bf354e39f434b01@dist-git>
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From: Peter Krempa <pkrempa@redhat.com>
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Date: Tue, 20 Jun 2017 14:45:37 +0200
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Subject: [PATCH] storage: Add helper to retrieve the backing store string of a
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 storage volume
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It is necessary for some parts of the code to refresh just data
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based on the based on the backing store string. Add a convenience
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function that will retrieve this data.
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(cherry picked from commit d97cfdc891f262e1b0cd3ed05f7ca2bb7ef7de1c)
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https://bugzilla.redhat.com/show_bug.cgi?id=1461303
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Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
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Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
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---
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 src/storage/storage_driver.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
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 src/storage/storage_driver.h |  3 +++
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 2 files changed, 47 insertions(+)
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diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
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index 61c5e7eff1..21af949170 100644
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--- a/src/storage/storage_driver.c
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+++ b/src/storage/storage_driver.c
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@@ -3370,6 +3370,50 @@ virStorageFileGetMetadata(virStorageSourcePtr src,
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 }
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+/**
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+ * virStorageFileGetBackingStoreStr:
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+ * @src: storage object
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+ *
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+ * Extracts the backing store string as stored in the storage volume described
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+ * by @src and returns it to the user. Caller is responsible for freeing it.
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+ * In case when the string can't be retrieved or does not exist NULL is
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+ * returned.
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+ */
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+char *
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+virStorageFileGetBackingStoreStr(virStorageSourcePtr src)
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+{
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+    virStorageSourcePtr tmp = NULL;
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+    char *buf = NULL;
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+    ssize_t headerLen;
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+    char *ret = NULL;
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+
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+    /* exit if we can't load information about the current image */
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+    if (!virStorageFileSupportsBackingChainTraversal(src))
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+        return NULL;
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+
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+    if (virStorageFileAccess(src, F_OK) < 0)
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+        return NULL;
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+
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+    if ((headerLen = virStorageFileReadHeader(src, VIR_STORAGE_MAX_HEADER,
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+                                              &buf)) < 0)
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+        return NULL;
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+
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+    if (!(tmp = virStorageSourceCopy(src, false)))
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+        goto cleanup;
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+
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+    if (virStorageFileGetMetadataInternal(tmp, buf, headerLen, NULL) < 0)
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+        goto cleanup;
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+
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+    VIR_STEAL_PTR(ret, tmp->backingStoreRaw);
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+
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+ cleanup:
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+    VIR_FREE(buf);
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+    virStorageSourceFree(tmp);
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+
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+    return ret;
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+}
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+
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+
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 static int
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 virStorageAddISCSIPoolSourceHost(virDomainDiskDefPtr def,
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                                  virStoragePoolDefPtr pooldef)
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diff --git a/src/storage/storage_driver.h b/src/storage/storage_driver.h
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index 530bc33880..ade05f7156 100644
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--- a/src/storage/storage_driver.h
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+++ b/src/storage/storage_driver.h
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@@ -54,6 +54,9 @@ int virStorageFileGetMetadata(virStorageSourcePtr src,
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                               bool report_broken)
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     ATTRIBUTE_NONNULL(1);
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+char *virStorageFileGetBackingStoreStr(virStorageSourcePtr src)
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+    ATTRIBUTE_NONNULL(1);
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+
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 int virStorageTranslateDiskSourcePool(virConnectPtr conn,
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                                       virDomainDiskDefPtr def);
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-- 
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2.13.1
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