[libvirt] [PATCH] Support QEMU's virtual FAT block device driver
Daniel P. Berrange
berrange at redhat.com
Tue Nov 17 15:16:01 UTC 2009
On Tue, Nov 17, 2009 at 04:08:08PM +0100, Daniel Veillard wrote:
> On Tue, Nov 17, 2009 at 01:20:15PM +0000, Daniel P. Berrange wrote:
> > Introduce a new type="dir" mode for <disks> that allows use of
> > QEMU's virtual FAT block device driver. eg
> >
> > <disk type='dir' device='floppy'>
> > <source dir='/tmp/test'/>
> > <target dev='fda' bus='fdc'/>
> > <readonly/>
> > </disk>
> >
> > gets turned into
> >
> > -drive file=fat:floppy:/tmp/test,if=floppy,index=0
> >
> > Only read-only disks are supported with virtual FAT mode
> >
> > * src/conf/domain_conf.c, src/conf/domain_conf.h: Add type="dir"
> > * docs/schemas/domain.rng: Document new disk type
> > * src/xen/xend_internal.c, src/xen/xm_internal.c: Raise error for
> > unsupported disk types
> > * tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom-empty.args: Fix
> > empty disk file handling
> > * tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.args,
> > tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.xml,
> > tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.args,
> > tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.xml
> > tests/qemuxml2argvtest.c: Test QEMU vitual FAT driver
> > * src/qemu/qemu_conf.c: Support generating fat:/some/dir type
> > disk args
> > * src/security/security_selinux.c: Temporarily skip labelling
> > of directory based disks
> > ---
> > docs/schemas/domain.rng | 16 ++++++
> > src/conf/domain_conf.c | 36 ++++++++++++--
> > src/conf/domain_conf.h | 1 +
> > src/qemu/qemu_conf.c | 49 ++++++++++++++++++-
> > src/security/security_selinux.c | 3 +
> > src/xen/xend_internal.c | 7 ++-
> > src/xen/xm_internal.c | 16 +++++-
> > .../qemuxml2argv-disk-cdrom-empty.args | 2 +-
> > .../qemuxml2argv-disk-drive-fat.args | 1 +
> > .../qemuxml2argv-disk-drive-fat.xml | 24 ++++++++++
> > .../qemuxml2argv-floppy-drive-fat.args | 1 +
> > .../qemuxml2argv-floppy-drive-fat.xml | 24 ++++++++++
> > tests/qemuxml2argvtest.c | 4 ++
> > tests/qemuxml2xmltest.c | 2 +
> > 14 files changed, 173 insertions(+), 13 deletions(-)
> > create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.args
> > create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.xml
> > create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.args
> > create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.xml
> >
> > diff --git a/docs/schemas/domain.rng b/docs/schemas/domain.rng
> > index 1bf44fd..7a3ef97 100644
> > --- a/docs/schemas/domain.rng
> > +++ b/docs/schemas/domain.rng
> > @@ -434,6 +434,22 @@
> > <ref name="diskspec"/>
> > </interleave>
> > </group>
> > + <group>
> > + <attribute name="type">
> > + <value>dir</value>
> > + </attribute>
> > + <interleave>
> > + <optional>
> > + <element name="source">
> > + <attribute name="dir">
> > + <ref name="absFilePath"/>
> > + </attribute>
> > + <empty/>
> > + </element>
> > + </optional>
> > + <ref name="diskspec"/>
> > + </interleave>
> > + </group>
> > <ref name="diskspec"/>
> > </choice>
> > </element>
> > diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> > index 0a7eef7..42820a7 100644
> > --- a/src/conf/domain_conf.c
> > +++ b/src/conf/domain_conf.c
> > @@ -90,7 +90,8 @@ VIR_ENUM_IMPL(virDomainDevice, VIR_DOMAIN_DEVICE_LAST,
> >
> > VIR_ENUM_IMPL(virDomainDisk, VIR_DOMAIN_DISK_TYPE_LAST,
> > "block",
> > - "file")
> > + "file",
> > + "dir")
> >
> > VIR_ENUM_IMPL(virDomainDiskDevice, VIR_DOMAIN_DISK_DEVICE_LAST,
> > "disk",
> > @@ -777,10 +778,22 @@ virDomainDiskDefParseXML(virConnectPtr conn,
> > if ((source == NULL) &&
> > (xmlStrEqual(cur->name, BAD_CAST "source"))) {
> >
> > - if (def->type == VIR_DOMAIN_DISK_TYPE_FILE)
> > + switch (def->type) {
> > + case VIR_DOMAIN_DISK_TYPE_FILE:
> > source = virXMLPropString(cur, "file");
> > - else
> > + break;
> > + case VIR_DOMAIN_DISK_TYPE_BLOCK:
> > source = virXMLPropString(cur, "dev");
> > + break;
> > + case VIR_DOMAIN_DISK_TYPE_DIR:
> > + source = virXMLPropString(cur, "dir");
> > + break;
> > + default:
> > + virDomainReportError(conn, VIR_ERR_INTERNAL_ERROR,
> > + _("unexpected disk type %s"),
> > + virDomainDiskTypeToString(def->type));
> > + goto error;
> > + }
> >
> > /* People sometimes pass a bogus '' source path
> > when they mean to omit the source element
> > @@ -3951,12 +3964,25 @@ virDomainDiskDefFormat(virConnectPtr conn,
> > }
> >
> > if (def->src) {
> > - if (def->type == VIR_DOMAIN_DISK_TYPE_FILE)
> > + switch (def->type) {
> > + case VIR_DOMAIN_DISK_TYPE_FILE:
> > virBufferEscapeString(buf, " <source file='%s'/>\n",
> > def->src);
> > - else
> > + break;
> > + case VIR_DOMAIN_DISK_TYPE_BLOCK:
> > virBufferEscapeString(buf, " <source dev='%s'/>\n",
> > def->src);
> > + break;
> > + case VIR_DOMAIN_DISK_TYPE_DIR:
> > + virBufferEscapeString(buf, " <source dir='%s'/>\n",
> > + def->src);
> > + break;
> > + default:
> > + virDomainReportError(conn, VIR_ERR_INTERNAL_ERROR,
> > + _("unexpected disk type %s"),
> > + virDomainDiskTypeToString(def->type));
> > + return -1;
> > + }
> > }
> >
> > virBufferVSprintf(buf, " <target dev='%s' bus='%s'/>\n",
> > diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
> > index 1fdb4fa..6201463 100644
> > --- a/src/conf/domain_conf.h
> > +++ b/src/conf/domain_conf.h
> > @@ -67,6 +67,7 @@ enum virDomainVirtType {
> > enum virDomainDiskType {
> > VIR_DOMAIN_DISK_TYPE_BLOCK,
> > VIR_DOMAIN_DISK_TYPE_FILE,
> > + VIR_DOMAIN_DISK_TYPE_DIR,
> >
> > VIR_DOMAIN_DISK_TYPE_LAST
> > };
> > diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
> > index c807688..2d72b4b 100644
> > --- a/src/qemu/qemu_conf.c
> > +++ b/src/qemu/qemu_conf.c
> > @@ -1980,8 +1980,30 @@ int qemudBuildCommandLine(virConnectPtr conn,
> > break;
> > }
> >
> > - virBufferVSprintf(&opt, "file=%s", disk->src ? disk->src : "");
> > - virBufferVSprintf(&opt, ",if=%s", bus);
> > + if (disk->src) {
> > + if (disk->type == VIR_DOMAIN_DISK_TYPE_DIR) {
> > + /* QEMU only supports magic FAT format for now */
> > + if (disk->driverType &&
> > + STRNEQ(disk->driverType, "fat")) {
> > + qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR,
> > + _("unsupported disk driver type for '%s'"),
> > + disk->driverType);
> > + goto error;
> > + }
> > + if (!disk->readonly) {
> > + qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR, "%s",
> > + _("cannot create virtual FAT disks in read-write mode"));
> > + goto error;
> > + }
> > + if (disk->device == VIR_DOMAIN_DISK_DEVICE_FLOPPY)
> > + virBufferVSprintf(&opt, "file=fat:floppy:%s,", disk->src);
> > + else
> > + virBufferVSprintf(&opt, "file=fat:%s,", disk->src);
> > + } else {
> > + virBufferVSprintf(&opt, "file=%s,", disk->src);
> > + }
> > + }
> > + virBufferVSprintf(&opt, "if=%s", bus);
> > if (disk->device == VIR_DOMAIN_DISK_DEVICE_CDROM)
> > virBufferAddLit(&opt, ",media=cdrom");
> > virBufferVSprintf(&opt, ",index=%d", idx);
> > @@ -1989,6 +2011,7 @@ int qemudBuildCommandLine(virConnectPtr conn,
> > disk->device == VIR_DOMAIN_DISK_DEVICE_DISK)
> > virBufferAddLit(&opt, ",boot=on");
> > if (disk->driverType &&
> > + disk->type != VIR_DOMAIN_DISK_TYPE_DIR &&
> > qemuCmdFlags & QEMUD_CMD_FLAG_DRIVE_FORMAT)
> > virBufferVSprintf(&opt, ",format=%s", disk->driverType);
> > if (disk->serial &&
> > @@ -2057,7 +2080,27 @@ int qemudBuildCommandLine(virConnectPtr conn,
> > }
> > }
> >
> > - snprintf(file, PATH_MAX, "%s", disk->src);
> > + if (disk->type == VIR_DOMAIN_DISK_TYPE_DIR) {
> > + /* QEMU only supports magic FAT format for now */
> > + if (disk->driverType &&
> > + STRNEQ(disk->driverType, "fat")) {
> > + qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR,
> > + _("unsupported disk driver type for '%s'"),
> > + disk->driverType);
> > + goto error;
> > + }
> > + if (!disk->readonly) {
> > + qemudReportError(conn, NULL, NULL, VIR_ERR_INTERNAL_ERROR, "%s",
> > + _("cannot create virtual FAT disks in read-write mode"));
> > + goto error;
> > + }
> > + if (disk->device == VIR_DOMAIN_DISK_DEVICE_FLOPPY)
> > + snprintf(file, PATH_MAX, "fat:floppy:%s", disk->src);
> > + else
> > + snprintf(file, PATH_MAX, "fat:%s", disk->src);
> > + } else {
> > + snprintf(file, PATH_MAX, "%s", disk->src);
> > + }
> >
> > ADD_ARG_LIT(dev);
> > ADD_ARG_LIT(file);
> > diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
> > index bd838e6..255ba53 100644
> > --- a/src/security/security_selinux.c
> > +++ b/src/security/security_selinux.c
> > @@ -687,6 +687,9 @@ SELinuxSetSecurityLabel(virConnectPtr conn,
> >
> > if (secdef->imagelabel) {
> > for (i = 0 ; i < vm->def->ndisks ; i++) {
> > + /* XXX fixme - we need to recursively label the entriy tree :-( */
> > + if (vm->def->disks[i]->type == VIR_DOMAIN_DISK_TYPE_DIR)
> > + continue;
> > if (SELinuxSetSecurityImageLabel(conn, vm, vm->def->disks[i]) < 0)
> > return -1;
> > }
> > diff --git a/src/xen/xend_internal.c b/src/xen/xend_internal.c
> > index d61e9e6..e370eb8 100644
> > --- a/src/xen/xend_internal.c
> > +++ b/src/xen/xend_internal.c
> > @@ -5375,11 +5375,16 @@ xenDaemonFormatSxprDisk(virConnectPtr conn ATTRIBUTE_UNUSED,
> > } else {
> > if (def->type == VIR_DOMAIN_DISK_TYPE_FILE) {
> > virBufferVSprintf(buf, "(uname 'file:%s')", def->src);
> > - } else {
> > + } else if (def->type == VIR_DOMAIN_DISK_TYPE_BLOCK) {
> > if (def->src[0] == '/')
> > virBufferVSprintf(buf, "(uname 'phy:%s')", def->src);
> > else
> > virBufferVSprintf(buf, "(uname 'phy:/dev/%s')", def->src);
> > + } else {
> > + virXendError(conn, VIR_ERR_CONFIG_UNSUPPORTED,
> > + _("unsupported disk type %s"),
> > + virDomainDiskTypeToString(def->type));
> > + return -1;
> > }
> > }
> > }
> > diff --git a/src/xen/xm_internal.c b/src/xen/xm_internal.c
> > index f833ce7..31cff12 100644
> > --- a/src/xen/xm_internal.c
> > +++ b/src/xen/xm_internal.c
> > @@ -1973,9 +1973,19 @@ static int xenXMDomainConfigFormatDisk(virConnectPtr conn,
> > if (STREQ(disk->driverName, "tap"))
> > virBufferVSprintf(&buf, "%s:", disk->driverType ? disk->driverType : "aio");
> > } else {
> > - virBufferVSprintf(&buf, "%s:",
> > - disk->type == VIR_DOMAIN_DISK_TYPE_FILE ?
> > - "file" : "phy");
> > + switch (disk->type) {
> > + case VIR_DOMAIN_DISK_TYPE_FILE:
> > + virBufferAddLit(&buf, "file:");
> > + break;
> > + case VIR_DOMAIN_DISK_TYPE_BLOCK:
> > + virBufferAddLit(&buf, "phy:");
> > + break;
> > + default:
> > + xenXMError(conn, VIR_ERR_INTERNAL_ERROR,
> > + _("unsupported disk type %s"),
> > + virDomainDiskTypeToString(disk->type));
> > + goto cleanup;
> > + }
> > }
> > virBufferVSprintf(&buf, "%s", disk->src);
> > }
> > diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom-empty.args b/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom-empty.args
> > index 1ef2602..1dd90d0 100644
> > --- a/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom-empty.args
> > +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-cdrom-empty.args
> > @@ -1 +1 @@
> > -LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M pc -m 214 -smp 1 -nographic -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -drive file=/dev/HostVG/QEMUGuest1,if=ide,index=0 -drive file=,if=ide,media=cdrom,index=2 -net none -serial none -parallel none -usb
> > +LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M pc -m 214 -smp 1 -nographic -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -drive file=/dev/HostVG/QEMUGuest1,if=ide,index=0 -drive if=ide,media=cdrom,index=2 -net none -serial none -parallel none -usb
> > diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.args b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.args
> > new file mode 100644
> > index 0000000..da1163b
> > --- /dev/null
> > +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.args
> > @@ -0,0 +1 @@
> > +LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M pc -m 214 -smp 1 -nographic -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -drive file=fat:/var/somefiles,if=ide,index=0,boot=on -net none -serial none -parallel none -usb
> > diff --git a/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.xml b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.xml
> > new file mode 100644
> > index 0000000..818ca93
> > --- /dev/null
> > +++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-fat.xml
> > @@ -0,0 +1,24 @@
> > +<domain type='qemu'>
> > + <name>QEMUGuest1</name>
> > + <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
> > + <memory>219200</memory>
> > + <currentMemory>219200</currentMemory>
> > + <vcpu>1</vcpu>
> > + <os>
> > + <type arch='i686' machine='pc'>hvm</type>
> > + <boot dev='hd'/>
> > + </os>
> > + <clock offset='utc'/>
> > + <on_poweroff>destroy</on_poweroff>
> > + <on_reboot>restart</on_reboot>
> > + <on_crash>destroy</on_crash>
> > + <devices>
> > + <emulator>/usr/bin/qemu</emulator>
> > + <disk type='dir' device='disk'>
> > + <driver name='qemu' type='fat'/>
> > + <source dir='/var/somefiles'/>
> > + <target dev='hda' bus='ide'/>
> > + <readonly/>
> > + </disk>
> > + </devices>
> > +</domain>
> > diff --git a/tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.args b/tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.args
> > new file mode 100644
> > index 0000000..4b4e3f4
> > --- /dev/null
> > +++ b/tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.args
> > @@ -0,0 +1 @@
> > +LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test /usr/bin/qemu -S -M pc -m 214 -smp 1 -nographic -monitor unix:/tmp/test-monitor,server,nowait -no-acpi -boot a -drive file=fat:floppy:/var/somefiles,if=floppy,index=0 -net none -serial none -parallel none -usb
> > diff --git a/tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.xml b/tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.xml
> > new file mode 100644
> > index 0000000..9e32b68
> > --- /dev/null
> > +++ b/tests/qemuxml2argvdata/qemuxml2argv-floppy-drive-fat.xml
> > @@ -0,0 +1,24 @@
> > +<domain type='qemu'>
> > + <name>QEMUGuest1</name>
> > + <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
> > + <memory>219200</memory>
> > + <currentMemory>219200</currentMemory>
> > + <vcpu>1</vcpu>
> > + <os>
> > + <type arch='i686' machine='pc'>hvm</type>
> > + <boot dev='fd'/>
> > + </os>
> > + <clock offset='utc'/>
> > + <on_poweroff>destroy</on_poweroff>
> > + <on_reboot>restart</on_reboot>
> > + <on_crash>destroy</on_crash>
> > + <devices>
> > + <emulator>/usr/bin/qemu</emulator>
> > + <disk type='dir' device='floppy'>
> > + <driver name='qemu' type='fat'/>
> > + <source dir='/var/somefiles'/>
> > + <target dev='fda' bus='fdc'/>
> > + <readonly/>
> > + </disk>
> > + </devices>
> > +</domain>
> > diff --git a/tests/qemuxml2argvtest.c b/tests/qemuxml2argvtest.c
> > index c948379..677c5b4 100644
> > --- a/tests/qemuxml2argvtest.c
> > +++ b/tests/qemuxml2argvtest.c
> > @@ -211,6 +211,10 @@ mymain(int argc, char **argv)
> > QEMUD_CMD_FLAG_DRIVE_BOOT);
> > DO_TEST("disk-drive-boot-cdrom", QEMUD_CMD_FLAG_DRIVE |
> > QEMUD_CMD_FLAG_DRIVE_BOOT);
> > + DO_TEST("floppy-drive-fat", QEMUD_CMD_FLAG_DRIVE |
> > + QEMUD_CMD_FLAG_DRIVE_BOOT | QEMUD_CMD_FLAG_DRIVE_FORMAT);
> > + DO_TEST("disk-drive-fat", QEMUD_CMD_FLAG_DRIVE |
> > + QEMUD_CMD_FLAG_DRIVE_BOOT | QEMUD_CMD_FLAG_DRIVE_FORMAT);
> > DO_TEST("disk-drive-fmt-qcow", QEMUD_CMD_FLAG_DRIVE |
> > QEMUD_CMD_FLAG_DRIVE_BOOT | QEMUD_CMD_FLAG_DRIVE_FORMAT);
> > DO_TEST("disk-drive-shared", QEMUD_CMD_FLAG_DRIVE |
> > diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c
> > index 25ef2ce..793900c 100644
> > --- a/tests/qemuxml2xmltest.c
> > +++ b/tests/qemuxml2xmltest.c
> > @@ -98,6 +98,8 @@ mymain(int argc, char **argv)
> > DO_TEST("disk-many");
> > DO_TEST("disk-xenvbd");
> > DO_TEST("disk-usb");
> > + DO_TEST("floppy-drive-fat");
> > + DO_TEST("disk-drive-fat");
> > DO_TEST("disk-drive-fmt-qcow");
> > DO_TEST("disk-drive-cache-v1-wt");
> > DO_TEST("disk-drive-cache-v1-wb");
>
> ACK, that's funky, and I guess this will stay a qemu only feature.
> One thing I wonder about the semantic is what happen if the underlying
> files get modified while QEmu tries to access that 'floppy'. I assume
> "domain can crash an burn" is just fine
Yes, QEMU has this to say
"What you should never do:
* use non-ASCII filenames ;
* use "-snapshot" together with ":rw:" ;
* expect it to work when loadvm'ing ;
* write to the FAT directory on the host system while
accessing it with the guest system. "
Regards,
Daniel
--
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