- virdevmapper: Handle kernel without device-mapper support

82bb167f-dont-cache-devmapper-major.patch,
  feb8564a-handle-no-devmapper.patch
  boo#1175465

OBS-URL: https://build.opensuse.org/package/show/Virtualization/libvirt?expand=0&rev=837

82bb167f-dont-cache-devmapper-major.patch

@@ -0,0 +1,86 @@
+commit 82bb167f0d15b733b23931205be3488b83cb9ec6
+Author: Michal Prívozník <mprivozn@redhat.com>
+Date:   Tue Aug 18 11:08:15 2020 +0200
+
+    virdevmapper: Don't cache device-mapper major
+    
+    The device mapper major is needed in virIsDevMapperDevice() which
+    determines whether given device is managed by device-mapper. This
+    number is obtained by parsing /proc/devices and then stored in a
+    global variable so that the file doesn't have to be parsed again.
+    However, as it turns out this logic is flawed - the major number
+    is not static and can change as it can be specified as a
+    parameter when loading the dm-mod module.
+    
+    Unfortunately, I was not able to come up with a good solution and
+    thus the /proc/devices file is being parsed every time we need
+    the device mapper major.
+    
+    Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
+    Reviewed-by: Peter Krempa <pkrempa@redhat.com>
+    Reviewed-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
+    Tested-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
+
+Index: libvirt-6.6.0/src/util/virdevmapper.c
+===================================================================
+--- libvirt-6.6.0.orig/src/util/virdevmapper.c
++++ libvirt-6.6.0/src/util/virdevmapper.c
+@@ -46,11 +46,9 @@
+ 
+ G_STATIC_ASSERT(BUF_SIZE > sizeof(struct dm_ioctl));
+ 
+-static unsigned int virDMMajor;
+-
+ 
+ static int
+-virDevMapperOnceInit(void)
++virDevMapperGetMajor(unsigned int *major)
+ {
+     g_autofree char *buf = NULL;
+     VIR_AUTOSTRINGLIST lines = NULL;
+@@ -69,7 +67,7 @@ virDevMapperOnceInit(void)
+ 
+         if (sscanf(lines[i], "%u %ms\n", &maj, &dev) == 2 &&
+             STREQ(dev, DM_NAME)) {
+-            virDMMajor = maj;
++            *major = maj;
+             break;
+         }
+     }
+@@ -85,9 +83,6 @@ virDevMapperOnceInit(void)
+ }
+ 
+ 
+-VIR_ONCE_GLOBAL_INIT(virDevMapper);
+-
+-
+ static void *
+ virDMIoctl(int controlFD, int cmd, struct dm_ioctl *dm, char **buf)
+ {
+@@ -305,9 +300,6 @@ virDevMapperGetTargets(const char *path,
+      * consist of devices or yet another targets. If that's the
+      * case, we have to stop recursion somewhere. */
+ 
+-    if (virDevMapperInitialize() < 0)
+-        return -1;
+-
+     if ((controlFD = virDMOpen()) < 0)
+         return -1;
+ 
+@@ -319,13 +311,14 @@ bool
+ virIsDevMapperDevice(const char *dev_name)
+ {
+     struct stat buf;
++    unsigned int major;
+ 
+-    if (virDevMapperInitialize() < 0)
++    if (virDevMapperGetMajor(&major) < 0)
+         return false;
+ 
+     if (!stat(dev_name, &buf) &&
+         S_ISBLK(buf.st_mode) &&
+-        major(buf.st_rdev) == virDMMajor)
++        major(buf.st_rdev) == major)
+         return true;
+ 
+     return false;

feb8564a-handle-no-devmapper.patch

@@ -0,0 +1,74 @@
+commit feb8564a3cc63bc8f68284063d53ec0d2d81a1cc
+Author: Michal Prívozník <mprivozn@redhat.com>
+Date:   Tue Aug 18 11:04:24 2020 +0200
+
+    virdevmapper: Handle kernel without device-mapper support
+    
+    In one of my latest patch (v6.6.0~30) I was trying to remove
+    libdevmapper use in favor of our own implementation. However, the
+    code did not take into account that device mapper can be not
+    compiled into the kernel (e.g. be a separate module that's not
+    loaded) in which case /proc/devices won't have the device-mapper
+    major number and thus virDevMapperGetTargets() and/or
+    virIsDevMapperDevice() fails.
+    
+    However, such failure is safe to ignore, because if device mapper
+    is missing then there can't be any multipath devices and thus we
+    don't need to allow the deps in CGroups, nor create them in the
+    domain private namespace, etc.
+    
+    Fixes: 22494556542c676d1b9e7f1c1f2ea13ac17e1e3e
+    Reported-by: Andrea Bolognani <abologna@redhat.com>
+    Reported-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
+    Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
+    Reviewed-by: Peter Krempa <pkrempa@redhat.com>
+    Reviewed-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
+    Tested-by: Christian Ehrhardt <christian.ehrhardt@canonical.com>
+
+Index: libvirt-6.6.0/src/util/virdevmapper.c
+===================================================================
+--- libvirt-6.6.0.orig/src/util/virdevmapper.c
++++ libvirt-6.6.0/src/util/virdevmapper.c
+@@ -54,6 +54,9 @@ virDevMapperGetMajor(unsigned int *major
+     VIR_AUTOSTRINGLIST lines = NULL;
+     size_t i;
+ 
++    if (!virFileExists(CONTROL_PATH))
++        return -2;
++
+     if (virFileReadAll(PROC_DEVICES, BUF_SIZE, &buf) < 0)
+         return -1;
+ 
+@@ -126,8 +129,13 @@ virDMOpen(void)
+ 
+     memset(&dm, 0, sizeof(dm));
+ 
+-    if ((controlFD = open(CONTROL_PATH, O_RDWR)) < 0)
++    if ((controlFD = open(CONTROL_PATH, O_RDWR)) < 0) {
++        if (errno == ENOENT)
++            return -2;
++
++        virReportSystemError(errno, _("Unable to open %s"), CONTROL_PATH);
+         return -1;
++    }
+ 
+     if (!virDMIoctl(controlFD, DM_VERSION, &dm, &tmp)) {
+         virReportSystemError(errno, "%s",
+@@ -300,8 +308,16 @@ virDevMapperGetTargets(const char *path,
+      * consist of devices or yet another targets. If that's the
+      * case, we have to stop recursion somewhere. */
+ 
+-    if ((controlFD = virDMOpen()) < 0)
++    if ((controlFD = virDMOpen()) < 0) {
++        if (controlFD == -2) {
++            /* The CONTROL_PATH doesn't exist. Probably the
++             * module isn't loaded, yet. Don't error out, just
++             * exit. */
++            return 0;
++        }
++
+         return -1;
++    }
+ 
+     return virDevMapperGetTargetsImpl(controlFD, path, devPaths, ttl);
+ }

libvirt.changes

@@ -1,3 +1,11 @@
+-------------------------------------------------------------------
+Wed Aug 19 19:36:52 UTC 2020 - James Fehlig <jfehlig@suse.com>
+
+- virdevmapper: Handle kernel without device-mapper support
+  82bb167f-dont-cache-devmapper-major.patch,
+  feb8564a-handle-no-devmapper.patch
+  boo#1175465
+
 -------------------------------------------------------------------
 Tue Aug 18 21:40:48 UTC 2020 - James Fehlig <jfehlig@suse.com>
 

libvirt.spec

@@ -337,6 +337,8 @@ Source99:       baselibs.conf
 Source100:      %{name}-rpmlintrc
 # Upstream patches
 Patch0:         2edd63a0-fix-virFileSetCOW-logic.patch
+Patch1:         82bb167f-dont-cache-devmapper-major.patch
+Patch2:         feb8564a-handle-no-devmapper.patch
 # Patches pending upstream review
 Patch100:       libxl-dom-reset.patch
 Patch101:       network-don-t-use-dhcp-authoritative-on-static-netwo.patch
@@ -877,6 +879,8 @@ libvirt plugin for NSS for translating domain names into IP addresses.
 %prep
 %setup -q
 %patch0 -p1
+%patch1 -p1
+%patch2 -p1
 %patch100 -p1
 %patch101 -p1
 %patch150 -p1