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Re: [libvirt] [Qemu-devel] [PATCH v2 3/3] raw-posix: Re-open host CD-ROM after media change
by Stefan Hajnoczi 06 Apr '11

06 Apr '11

On Tue, Mar 29, 2011 at 8:04 PM, Stefan Hajnoczi <stefanha(a)linux.vnet.ibm.com> wrote: > Piggy-back on the guest CD-ROM polling to poll on the host. Open and > close the host CD-ROM file descriptor to ensure we read the new size and > not a stale size. > > Two things are going on here: > > 1. If hald/udisks is not already polling CD-ROMs on the host then > re-opening the CD-ROM causes the host to read the new medium's size. > > 2. There is a bug in Linux which means the CD-ROM file descriptor must > be re-opened in order for lseek(2) to see the new size. The > inode size gets out of sync with the underlying device (which you can > confirm by checking that /sys/block/sr0/size and lseek(2) do not > match after media change). I have raised this with the > maintainers but we need a workaround for the foreseeable future. > > Note that these changes are all in a #ifdef __linux__ section. > > Signed-off-by: Stefan Hajnoczi <stefanha(a)linux.vnet.ibm.com> > --- > block/raw-posix.c | 26 ++++++++++++++++++++++---- > 1 files changed, 22 insertions(+), 4 deletions(-) > > diff --git a/block/raw-posix.c b/block/raw-posix.c > index 6b72470..8b5205c 100644 > --- a/block/raw-posix.c > +++ b/block/raw-posix.c > @@ -1238,10 +1238,28 @@ static int cdrom_is_inserted(BlockDriverState *bs) > BDRVRawState *s = bs->opaque; > int ret; > > - ret = ioctl(s->fd, CDROM_DRIVE_STATUS, CDSL_CURRENT); > - if (ret == CDS_DISC_OK) > - return 1; > - return 0; > + /* > + * Close the file descriptor if no medium is present and open it to poll > + * again. This ensures the medium size is refreshed. If the file > + * descriptor is kept open the size can become stale. This is essentially > + * replicating CD-ROM polling but is driven by the guest. As the guest > + * polls, we poll the host. > + */ > + > + if (s->fd == -1) { > + s->fd = qemu_open(bs->filename, s->open_flags, 0644); > + if (s->fd < 0) { > + return 0; > + } > + } > + > + ret = (ioctl(s->fd, CDROM_DRIVE_STATUS, CDSL_CURRENT) == CDS_DISC_OK); > + > + if (!ret) { > + close(s->fd); > + s->fd = -1; > + } > + return ret; > } > > static int cdrom_eject(BlockDriverState *bs, int eject_flag) > -- > 1.7.4.1 > > > There is an issue with reopening host devices in QEMU when running under libvirt. It appears that libvirt chowns image files (including device nodes) so that the launched QEMU process can access them. Unfortunately after media change on host devices udev will reset the ownership of the device node. This causes open(2) to fail with EACCES since the QEMU process does not have the right uid/gid/groups and libvirt is unaware that the file's ownership has changed. In order for media change to work with Linux host CD-ROM it is necessary to reopen the file (otherwise the inode size will not refresh, this is an issue with existing kernels). How can libvirt's security model be made to support this case? In theory udev could be temporarily configured with libvirt permissions for the CD-ROM device while passed through to the guest, but is that feasible? Stefan

8 29

[libvirt] [PATCH] qemu: unlock qemu driver before return
by Hu Tao 06 Apr '11

06 Apr '11

--- src/qemu/qemu_driver.c | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c index 104e92d..6e3edde 100644 --- a/src/qemu/qemu_driver.c +++ b/src/qemu/qemu_driver.c @@ -2068,12 +2068,14 @@ static int qemudDomainSave(virDomainPtr dom, const char *path) qemuReportError(VIR_ERR_OPERATION_FAILED, "%s", _("Invalid save image format specified " "in configuration file")); + qemuDriverUnlock(driver); return -1; } if (!qemudCompressProgramAvailable(compressed)) { qemuReportError(VIR_ERR_OPERATION_FAILED, "%s", _("Compression program for image format " "in configuration file isn't available")); + qemuDriverUnlock(driver); return -1; } } -- 1.7.3.1

3 11

[libvirt] qemu: Add timeout for monitor to avoid virsh getting stuck when monitor gets die.
by Mark Wu 06 Apr '11

06 Apr '11

Hello Guys, When the qemu process becomes hung, virsh will get stuck on the hung guest and can't move forward. It can be reproduced by the following steps: 1. setup a virt guest with qemu-kvm, and start it 2. stop qemu process with following: kill -STOP `ps aux | grep qemu | grep -v grep | awk '{print $2}'` 3. run the following command: virsh list I think we can add a timeout for qemu monitor to resolve this problem: using virCondWaitUntil instead of virCondWait in qemuMonitorSend. What's your opinions? Thanks!

1 1

[libvirt] [PATCH 0/2] Log enhancement
by Naoya Horiguchi 06 Apr '11

06 Apr '11

Hi, Following patches improve logging feature of libvirt. Please see individual patches for more details. [PATCH 1/2] extend logging to record configuration-related events on host machine [PATCH 2/2] qemu: extend logging to record guest configuration events Thanks, Naoya Horiguchi

3 5

[libvirt] [libvirt-php] API to add/remove disk to/from domain
by Conor Murphy 05 Apr '11

05 Apr '11

Hi, How do I add/remove a disk to a domain using the libvirt-php API? Thanks, Conor

2 2

[libvirt] [PATCH] Allow relative path for qemu backing file
by Jesse Cook 05 Apr '11

05 Apr '11

This patch enables the relative backing file path support provided by qemu-img create. If a relative path is specified for the backing file, it is converted to an absolute path using the storage pool path. The absolute path is used to verify that the backing file exists. If the backing file exists, the relative path is allowed and will be provided to qemu-img create. This patch takes the place of a previous patch: http://www.redhat.com/archives/libvir-list/2011-March/msg00179.html --- src/storage/storage_backend.c | 18 +++++++++++++++++- 1 files changed, 17 insertions(+), 1 deletions(-) diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c index 2eede74..abdc2dd 100644 --- a/src/storage/storage_backend.c +++ b/src/storage/storage_backend.c @@ -666,6 +666,9 @@ virStorageBackendCreateQemuImg(virConnectPtr conn, } if (vol->backingStore.path) { + int accessRetCode = -1; + + char *absolutePath = NULL; /* XXX: Not strictly required: qemu-img has an option a different * backing store, not really sure what use it serves though, and it @@ -686,7 +689,20 @@ virStorageBackendCreateQemuImg(virConnectPtr conn, vol->backingStore.format); return -1; } - if (access(vol->backingStore.path, R_OK) != 0) { + + /* Convert relative backing store paths to absolute paths for access + * validation. + */ + if ('/' != *(vol->backingStore.path)) { + virAsprintf(&absolutePath, "%s/%s", pool->def->target.path, + vol->backingStore.path); + + } else { + virAsprintf(&absolutePath, "%s", vol->backingStore.path); + } + accessRetCode = access(absolutePath, R_OK); + VIR_FREE(absolutePath); + if (accessRetCode != 0) { virReportSystemError(errno, _("inaccessible backing store volume %s"), vol->backingStore.path); -- 1.7.4.1

3 4

[libvirt] [PATCH] libxl: avoid compiler warning
by Eric Blake 05 Apr '11

05 Apr '11

cc1: warnings being treated as errors libxl/libxl_driver.c: In function 'libxlDomainSetVcpusFlags': libxl/libxl_driver.c:1570:14: error: cast from function call of type 'double' to non-matching type 'unsigned int' [-Wbad-function-cast] libxl/libxl_driver.c:1578:15: error: cast from function call of type 'double' to non-matching type 'unsigned int' [-Wbad-function-cast] This was the only use of floor() and ceil(), and floating-point is overkill for power-of-two manipulations. * src/libxl/libxl_driver.c (libxlDomainSetVcpusFlags): Avoid -lm for trivial computations. --- Pushing under the build-breaker rule. src/libxl/libxl_driver.c | 5 ++--- 1 files changed, 2 insertions(+), 3 deletions(-) diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 75f99c1..8cc4469 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -1567,15 +1567,14 @@ libxlDomainSetVcpusFlags(virDomainPtr dom, unsigned int nvcpus, if (!(def = virDomainObjGetPersistentDef(driver->caps, vm))) goto cleanup; - maplen = (unsigned int) ceil((double) nvcpus / 8); + maplen = VIR_CPU_MAPLEN(nvcpus); if (VIR_ALLOC_N(bitmask, maplen) < 0) { virReportOOMError(); goto cleanup; } - memset(bitmask, 0, maplen); for (i = 0; i < nvcpus; ++i) { - pos = (unsigned int) floor((double) i / 8); + pos = i / 8; bitmask[pos] |= 1 << (i % 8); } -- 1.7.4

1 0

[libvirt] [PATCH] Fix typo in systemtap tapset directrory name
by Daniel P. Berrange 05 Apr '11

05 Apr '11

The systemtap directory for tapsets is called /usr/share/systemtap/tapset Not /usr/share/systemtap/tapsets * daemon/Makefile.am,libvirt.spec.in: s/tapsets/tapset/ --- daemon/Makefile.am | 2 +- libvirt.spec.in | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/daemon/Makefile.am b/daemon/Makefile.am index 0fde04c..cacec1c 100644 --- a/daemon/Makefile.am +++ b/daemon/Makefile.am @@ -165,7 +165,7 @@ nodist_libvirtd_SOURCES = probes.h BUILT_SOURCES += probes.h -tapsetdir = $(datadir)/systemtap/tapsets +tapsetdir = $(datadir)/systemtap/tapset tapset_DATA = libvirtd.stp probes.h: probes.d diff --git a/libvirt.spec.in b/libvirt.spec.in index 724b9b7..4162fba 100644 --- a/libvirt.spec.in +++ b/libvirt.spec.in @@ -898,7 +898,7 @@ fi %config(noreplace) %{_sysconfdir}/sysconfig/libvirtd %config(noreplace) %{_sysconfdir}/libvirt/libvirtd.conf %if %{with_dtrace} -%{_datadir}/systemtap/tapsets/libvirtd.stp +%{_datadir}/systemtap/tapset/libvirtd.stp %endif %dir %attr(0700, root, root) %{_localstatedir}/log/libvirt/qemu/ %dir %attr(0700, root, root) %{_localstatedir}/log/libvirt/lxc/ -- 1.7.4

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[libvirt] [PATCH v3] Improve SCSI volume key generation
by Daniel P. Berrange 05 Apr '11

05 Apr '11

The SCSI volumes get a better 'key' field based on the fully qualified volume path. All SCSI volumes have a unique serial available in hardware which can be obtained by sending a suitable SCSI command. Call out to udev's 'scsi_id' command to fetch this value In v3: - Use virCommandSetOutputBuffer/virCommandRun instead of VIR_FDOPEN - Skip serial if it matches empty string * src/storage/storage_backend_scsi.c: Improve volume key field value stability and uniqueness --- src/storage/storage_backend_scsi.c | 45 ++++++++++++++++++++++++++++++++--- 1 files changed, 41 insertions(+), 4 deletions(-) diff --git a/src/storage/storage_backend_scsi.c b/src/storage/storage_backend_scsi.c index d880d65..da34547 100644 --- a/src/storage/storage_backend_scsi.c +++ b/src/storage/storage_backend_scsi.c @@ -33,6 +33,7 @@ #include "memory.h" #include "logging.h" #include "files.h" +#include "command.h" #define VIR_FROM_THIS VIR_FROM_STORAGE @@ -160,6 +161,45 @@ cleanup: return ret; } + +static char * +virStorageBackendSCSISerial(const char *dev) +{ + char *serial = NULL; +#ifdef HAVE_UDEV + virCommandPtr cmd = virCommandNewArgList( + "/lib/udev/scsi_id", + "--replace-whitespace", + "--whitelisted", + "--device", dev, + NULL + ); + + /* Run the program and capture its output */ + virCommandSetOutputBuffer(cmd, &serial); + if (virCommandRun(cmd, NULL) < 0) + goto cleanup; +#endif + + if (serial && STRNEQ(serial, "")) { + char *nl = strchr(serial, '\n'); + if (nl) + *nl = '\0'; + } else { + VIR_FREE(serial); + if (!(serial = strdup(dev))) + virReportOOMError(); + } + +#ifdef HAVE_UDEV +cleanup: + virCommandFree(cmd); +#endif + + return serial; +} + + static int virStorageBackendSCSINewLun(virStoragePoolObjPtr pool, uint32_t host ATTRIBUTE_UNUSED, @@ -233,10 +273,7 @@ virStorageBackendSCSINewLun(virStoragePoolObjPtr pool, goto free_vol; } - /* XXX should use logical unit's UUID instead */ - vol->key = strdup(vol->target.path); - if (vol->key == NULL) { - virReportOOMError(); + if (!(vol->key = virStorageBackendSCSISerial(vol->target.path))) { retval = -1; goto free_vol; } -- 1.7.4

2 1

[libvirt] [PATCH] qemu: Ignore unusable binaries
by Jiri Denemark 05 Apr '11

05 Apr '11

When initializing qemu guest capabilities, we should ignore qemu binaries that we are not able to extract version/help info from since they will be unusable for creating domains anyway. Ignoring them is also much better than letting initialization of qemu driver fail. --- src/qemu/qemu_capabilities.c | 11 ++++++++--- 1 files changed, 8 insertions(+), 3 deletions(-) diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c index f86e7f5..63486cc 100644 --- a/src/qemu/qemu_capabilities.c +++ b/src/qemu/qemu_capabilities.c @@ -490,6 +490,12 @@ qemuCapsInitGuest(virCapsPtr caps, if (!binary) return 0; + /* Ignore binary if extracting version info fails */ + if (qemuCapsExtractVersionInfo(binary, info->arch, NULL, &qemuCaps) < 0) { + ret = 0; + goto cleanup; + } + if (stat(binary, &st) == 0) { binary_mtime = st.st_mtime; } else { @@ -554,9 +560,8 @@ qemuCapsInitGuest(virCapsPtr caps, !virCapabilitiesAddGuestFeature(guest, "cpuselection", 1, 0)) goto error; - if (qemuCapsExtractVersionInfo(binary, info->arch, NULL, &qemuCaps) < 0 || - (qemuCapsGet(qemuCaps, QEMU_CAPS_BOOTINDEX) && - !virCapabilitiesAddGuestFeature(guest, "deviceboot", 1, 0))) + if (qemuCapsGet(qemuCaps, QEMU_CAPS_BOOTINDEX) && + !virCapabilitiesAddGuestFeature(guest, "deviceboot", 1, 0)) goto error; if (hvm) { -- 1.7.4.1

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