From 26c8c3ed35e6986afdff0214da1e21aefddacb3e Mon Sep 17 00:00:00 2001
From: Peter Krempa <pkrempa@redhat.com>
Date: Fri, 7 Aug 2015 11:01:49 +0200
Subject: [PATCH] qemu: Fix reporting of physical capacity for block devices

Qemu reports physical size 0 for block devices. As 15fa84acbb55ebfee6a4
changed the behavior of qemuDomainGetBlockInfo to just query the monitor
this created a regression since we didn't report the size correctly any
more.

This patch adds code to refresh the physical size of a block device by
opening it and seeking to the end and uses it both in
qemuDomainGetBlockInfo and also in qemuDomainGetStatsOneBlock that was
broken since it was introduced in this respect.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1250982
(cherry picked from commit 8dc27259255b79758367789ed272e909bdb56735)
---
 src/libvirt_private.syms  |  1 +
 src/qemu/qemu_driver.c    | 18 ++++++++++++++++--
 src/util/virstoragefile.c | 39 +++++++++++++++++++++++++++++++++++++++
 src/util/virstoragefile.h |  2 ++
 4 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 0a45cdf5e3..b70f4498fc 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2156,6 +2156,7 @@ virStorageSourceParseRBDColonString;
 virStorageSourcePoolDefFree;
 virStorageSourcePoolModeTypeFromString;
 virStorageSourcePoolModeTypeToString;
+virStorageSourceUpdateBlockPhysicalSize;
 virStorageTypeFromString;
 virStorageTypeToString;
 
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 641abac917..9ffced3c7b 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -11823,8 +11823,16 @@ qemuDomainGetBlockInfo(virDomainPtr dom,
         info->allocation = entry->wr_highest_offset;
     }
 
+    if (entry->physical) {
+        info->physical = entry->physical;
+    } else {
+        if (virStorageSourceUpdateBlockPhysicalSize(disk->src, true) < 0)
+            goto endjob;
+
+        info->physical = disk->src->physical;
+    }
+
     info->capacity = entry->capacity;
-    info->physical = entry->physical;
 
     ret = 0;
 
@@ -19270,9 +19278,15 @@ qemuDomainGetStatsOneBlock(virQEMUDriverPtr driver,
     if (entry->capacity)
         QEMU_ADD_BLOCK_PARAM_ULL(record, maxparams, block_idx,
                                  "capacity", entry->capacity);
-    if (entry->physical)
+    if (entry->physical) {
         QEMU_ADD_BLOCK_PARAM_ULL(record, maxparams, block_idx,
                                  "physical", entry->physical);
+    } else {
+        if (virStorageSourceUpdateBlockPhysicalSize(src, false) == 0) {
+            QEMU_ADD_BLOCK_PARAM_ULL(record, maxparams, block_idx,
+                                     "physical", src->physical);
+        }
+    }
 
     ret = 0;
  cleanup:
diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c
index 6c3017cef9..2aa1d90d65 100644
--- a/src/util/virstoragefile.c
+++ b/src/util/virstoragefile.c
@@ -2587,6 +2587,45 @@ virStorageSourceNewFromBacking(virStorageSourcePtr parent)
 }
 
 
+/**
+ * @src: disk source definiton structure
+ * @report: report libvirt errors if set to true
+ *
+ * Updates src->physical for block devices since qemu doesn't report the current
+ * size correctly for them. Returns 0 on success, -1 on error.
+ */
+int
+virStorageSourceUpdateBlockPhysicalSize(virStorageSourcePtr src,
+                                        bool report)
+{
+    int fd = -1;
+    off_t end;
+    int ret = -1;
+
+    if (virStorageSourceGetActualType(src) != VIR_STORAGE_TYPE_BLOCK)
+        return 0;
+
+    if ((fd = open(src->path, O_RDONLY)) < 0) {
+        if (report)
+            virReportSystemError(errno, _("failed to open block device '%s'"),
+                                 src->path);
+        return -1;
+    }
+
+    if ((end = lseek(fd, 0, SEEK_END)) == (off_t) -1) {
+        if (report)
+            virReportSystemError(errno,
+                                 _("failed to seek to end of '%s'"), src->path);
+    } else {
+        src->physical = end;
+        ret = 0;
+    }
+
+    VIR_FORCE_CLOSE(fd);
+    return ret;
+}
+
+
 static char *
 virStorageFileCanonicalizeFormatPath(char **components,
                                      size_t ncomponents,
diff --git a/src/util/virstoragefile.h b/src/util/virstoragefile.h
index aa17a00e54..b98fe25871 100644
--- a/src/util/virstoragefile.h
+++ b/src/util/virstoragefile.h
@@ -362,6 +362,8 @@ bool virStorageSourceIsLocalStorage(virStorageSourcePtr src);
 bool virStorageSourceIsEmpty(virStorageSourcePtr src);
 void virStorageSourceFree(virStorageSourcePtr def);
 void virStorageSourceBackingStoreClear(virStorageSourcePtr def);
+int virStorageSourceUpdateBlockPhysicalSize(virStorageSourcePtr src,
+                                            bool report);
 virStorageSourcePtr virStorageSourceNewFromBacking(virStorageSourcePtr parent);
 virStorageSourcePtr virStorageSourceCopy(const virStorageSource *src,
                                          bool backingChain)