From c3a1856890b9d75df08a66a95ac5a217b3aadc89 Mon Sep 17 00:00:00 2001 From: Christian Schoenebeck Date: Mon, 30 Mar 2020 20:05:33 +0200 Subject: [PATCH] conf: add 'multidevs' option MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Introduce new 'multidevs' option for filesystem. This option prevents misbehaviours on guest if a qemu 9pfs export contains multiple devices, due to the potential file ID collisions this otherwise may cause. Signed-off-by: Christian Schoenebeck Signed-off-by: Ján Tomko Reviewed-by: Ján Tomko --- docs/formatdomain.html.in | 40 ++++++++++++- docs/schemas/domaincommon.rng | 10 ++++ src/conf/domain_conf.c | 29 ++++++++++ src/conf/domain_conf.h | 13 +++++ .../qemuxml2argvdata/virtio-9p-multidevs.xml | 53 ++++++++++++++++++ .../virtio-9p-multidevs.x86_64-latest.xml | 56 +++++++++++++++++++ tests/qemuxml2xmltest.c | 2 + 7 files changed, 202 insertions(+), 1 deletion(-) create mode 100644 tests/qemuxml2argvdata/virtio-9p-multidevs.xml create mode 100644 tests/qemuxml2xmloutdata/virtio-9p-multidevs.x86_64-latest.xml diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index aaeb05961f..fbffb16866 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -3973,7 +3973,7 @@ <source name='my-vm-template'/> <target dir='/'/> </filesystem> - <filesystem type='mount' accessmode='passthrough'> + <filesystem type='mount' accessmode='passthrough' multidevs='remap'> <driver type='path' wrpolicy='immediate'/> <source dir='/export/to/guest'/> <target dir='/import/from/host'/> @@ -4098,6 +4098,44 @@ for more details.

+

+ The filesystem element has an optional attribute multidevs + which specifies how to deal with a filesystem export containing more than + one device, in order to avoid file ID collisions on guest when using 9pfs + (since 6.3.0, requires QEMU 4.2). + This attribute is not available for virtiofs. The possible values are: +

+ +
+
default
+
+ Use QEMU's default setting (which currently is warn). +
+
remap
+
+ This setting allows guest to access multiple devices per export without + encountering misbehaviours. Inode numbers from host are automatically + remapped on guest to actively prevent file ID collisions if guest + accesses one export containing multiple devices. +
+
forbid
+
+ Only allow to access one device per export by guest. Attempts to access + additional devices on the same export will cause the individual + filesystem access by guest to fail with an error and being logged (once) + as error on host side. +
+
warn
+
+ This setting resembles the behaviour of 9pfs prior to QEMU 4.2, that is + no action is performed to prevent any potential file ID collisions if an + export contains multiple devices, with the only exception: a warning is + logged (once) on host side now. This setting may lead to misbehaviours + on guest side if more than one device is exported per export, due to the + potential file ID collisions this may cause on guest side in that case. +
+
+

diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng index 1807df521c..dcf2e09db8 100644 --- a/docs/schemas/domaincommon.rng +++ b/docs/schemas/domaincommon.rng @@ -2706,6 +2706,16 @@ + + + + default + remap + forbid + warn + + + diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c index 914e03c705..460f8064be 100644 --- a/src/conf/domain_conf.c +++ b/src/conf/domain_conf.c @@ -502,6 +502,14 @@ VIR_ENUM_IMPL(virDomainFSModel, "virtio-non-transitional", ); +VIR_ENUM_IMPL(virDomainFSMultidevs, + VIR_DOMAIN_FS_MULTIDEVS_LAST, + "default", + "remap", + "forbid", + "warn", +); + VIR_ENUM_IMPL(virDomainFSCacheMode, VIR_DOMAIN_FS_CACHE_MODE_LAST, "default", @@ -11389,6 +11397,7 @@ virDomainFSDefParseXML(virDomainXMLOptionPtr xmlopt, g_autofree char *usage = NULL; g_autofree char *units = NULL; g_autofree char *model = NULL; + g_autofree char *multidevs = NULL; ctxt->node = node; @@ -11427,6 +11436,17 @@ virDomainFSDefParseXML(virDomainXMLOptionPtr xmlopt, } } + multidevs = virXMLPropString(node, "multidevs"); + if (multidevs) { + if ((def->multidevs = virDomainFSMultidevsTypeFromString(multidevs)) < 0) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, + _("unknown multidevs '%s'"), multidevs); + goto error; + } + } else { + def->multidevs = VIR_DOMAIN_FS_MULTIDEVS_DEFAULT; + } + if (virDomainParseScaledValue("./space_hard_limit[1]", NULL, ctxt, &def->space_hard_limit, 1, ULLONG_MAX, false) < 0) @@ -25385,6 +25405,7 @@ virDomainFSDefFormat(virBufferPtr buf, const char *accessmode = virDomainFSAccessModeTypeToString(def->accessmode); const char *fsdriver = virDomainFSDriverTypeToString(def->fsdriver); const char *wrpolicy = virDomainFSWrpolicyTypeToString(def->wrpolicy); + const char *multidevs = virDomainFSMultidevsTypeToString(def->multidevs); const char *src = def->src->path; g_auto(virBuffer) driverAttrBuf = VIR_BUFFER_INITIALIZER; g_auto(virBuffer) driverBuf = VIR_BUFFER_INIT_CHILD(buf); @@ -25403,6 +25424,12 @@ virDomainFSDefFormat(virBufferPtr buf, return -1; } + if (!multidevs) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("unexpected multidevs %d"), def->multidevs); + return -1; + } + virBufferAsprintf(buf, "model)); } + if (def->multidevs) + virBufferAsprintf(buf, " multidevs='%s'", multidevs); virBufferAddLit(buf, ">\n"); virBufferAdjustIndent(buf, 2); diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h index 33875d942f..2038b54c32 100644 --- a/src/conf/domain_conf.h +++ b/src/conf/domain_conf.h @@ -796,6 +796,18 @@ typedef enum { VIR_DOMAIN_FS_WRPOLICY_LAST } virDomainFSWrpolicy; +/* How to handle exports containing multiple devices. */ +typedef enum { + VIR_DOMAIN_FS_MULTIDEVS_DEFAULT = 0, /* Use QEMU's default setting */ + VIR_DOMAIN_FS_MULTIDEVS_REMAP, /* Remap inodes from host to guest */ + VIR_DOMAIN_FS_MULTIDEVS_FORBID, /* Prohibit more than one device */ + VIR_DOMAIN_FS_MULTIDEVS_WARN, /* Just log a warning if multiple devices */ + + VIR_DOMAIN_FS_MULTIDEVS_LAST +} virDomainFSMultidevs; + +VIR_ENUM_DECL(virDomainFSMultidevs); + typedef enum { VIR_DOMAIN_FS_MODEL_DEFAULT = 0, VIR_DOMAIN_FS_MODEL_VIRTIO, @@ -820,6 +832,7 @@ struct _virDomainFSDef { int wrpolicy; /* enum virDomainFSWrpolicy */ int format; /* virStorageFileFormat */ int model; /* virDomainFSModel */ + int multidevs; /* virDomainFSMultidevs */ unsigned long long usage; /* in bytes */ virStorageSourcePtr src; char *dst; diff --git a/tests/qemuxml2argvdata/virtio-9p-multidevs.xml b/tests/qemuxml2argvdata/virtio-9p-multidevs.xml new file mode 100644 index 0000000000..7a3b865415 --- /dev/null +++ b/tests/qemuxml2argvdata/virtio-9p-multidevs.xml @@ -0,0 +1,53 @@ + + QEMUGuest1 + c7a5fdbd-edaf-9455-926a-d65c16db1809 + 219136 + 219136 + 1 + + hvm + + + + destroy + restart + destroy + + /usr/bin/qemu-system-x86_64 + +

+ + +
+ + + + + +
+ + + + +
+ + + + +
+ + + + + + + + + + + + +
+ + + diff --git a/tests/qemuxml2xmloutdata/virtio-9p-multidevs.x86_64-latest.xml b/tests/qemuxml2xmloutdata/virtio-9p-multidevs.x86_64-latest.xml new file mode 100644 index 0000000000..4ea75ff8e3 --- /dev/null +++ b/tests/qemuxml2xmloutdata/virtio-9p-multidevs.x86_64-latest.xml @@ -0,0 +1,56 @@ + + QEMUGuest1 + c7a5fdbd-edaf-9455-926a-d65c16db1809 + 219136 + 219136 + 1 + + hvm + + + + qemu64 + + + destroy + restart + destroy + + /usr/bin/qemu-system-x86_64 + +
+ + +
+ + + + + +
+ + + + +
+ + + + +
+ + + + + + + + + + + + +
+ + + diff --git a/tests/qemuxml2xmltest.c b/tests/qemuxml2xmltest.c index a0d27fdcf8..b4c83fccca 100644 --- a/tests/qemuxml2xmltest.c +++ b/tests/qemuxml2xmltest.c @@ -1485,6 +1485,8 @@ mymain(void) DO_TEST_CAPS_ARCH_LATEST("x86_64-default-cpu-kvm-q35-4.2", "x86_64"); DO_TEST_CAPS_ARCH_LATEST("x86_64-default-cpu-tcg-q35-4.2", "x86_64"); + DO_TEST_CAPS_LATEST("virtio-9p-multidevs"); + if (getenv("LIBVIRT_SKIP_CLEANUP") == NULL) virFileDeleteTree(fakerootdir);