qemu/hw/block/nvme-ns.c
Kevin Wolf 86b1cf3227 block: Separate blk_is_writable() and blk_supports_write_perm()
Currently, blk_is_read_only() tells whether a given BlockBackend can
only be used in read-only mode because its root node is read-only. Some
callers actually try to answer a slightly different question: Is the
BlockBackend configured to be writable, by taking write permissions on
the root node?

This can differ, for example, for CD-ROM devices which don't take write
permissions, but may be backed by a writable image file. scsi-cd allows
write requests to the drive if blk_is_read_only() returns false.
However, the write request will immediately run into an assertion
failure because the write permission is missing.

This patch introduces separate functions for both questions.
blk_supports_write_perm() answers the question whether the block
node/image file can support writable devices, whereas blk_is_writable()
tells whether the BlockBackend is currently configured to be writable.

All calls of blk_is_read_only() are converted to one of the two new
functions.

Fixes: https://bugs.launchpad.net/bugs/1906693
Cc: qemu-stable@nongnu.org
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210118123448.307825-2-kwolf@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2021-01-27 20:45:20 +01:00

170 lines
3.9 KiB
C

/*
* QEMU NVM Express Virtual Namespace
*
* Copyright (c) 2019 CNEX Labs
* Copyright (c) 2020 Samsung Electronics
*
* Authors:
* Klaus Jensen <k.jensen@samsung.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See the
* COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qemu/units.h"
#include "qemu/cutils.h"
#include "qemu/log.h"
#include "hw/block/block.h"
#include "hw/pci/pci.h"
#include "sysemu/sysemu.h"
#include "sysemu/block-backend.h"
#include "qapi/error.h"
#include "hw/qdev-properties.h"
#include "hw/qdev-core.h"
#include "nvme.h"
#include "nvme-ns.h"
static void nvme_ns_init(NvmeNamespace *ns)
{
NvmeIdNs *id_ns = &ns->id_ns;
int lba_index = NVME_ID_NS_FLBAS_INDEX(ns->id_ns.flbas);
if (blk_get_flags(ns->blkconf.blk) & BDRV_O_UNMAP) {
ns->id_ns.dlfeat = 0x9;
}
id_ns->lbaf[lba_index].ds = 31 - clz32(ns->blkconf.logical_block_size);
id_ns->nsze = cpu_to_le64(nvme_ns_nlbas(ns));
/* no thin provisioning */
id_ns->ncap = id_ns->nsze;
id_ns->nuse = id_ns->ncap;
}
static int nvme_ns_init_blk(NvmeCtrl *n, NvmeNamespace *ns, Error **errp)
{
bool read_only;
if (!blkconf_blocksizes(&ns->blkconf, errp)) {
return -1;
}
read_only = !blk_supports_write_perm(ns->blkconf.blk);
if (!blkconf_apply_backend_options(&ns->blkconf, read_only, false, errp)) {
return -1;
}
ns->size = blk_getlength(ns->blkconf.blk);
if (ns->size < 0) {
error_setg_errno(errp, -ns->size, "could not get blockdev size");
return -1;
}
if (blk_enable_write_cache(ns->blkconf.blk)) {
n->features.vwc = 0x1;
}
return 0;
}
static int nvme_ns_check_constraints(NvmeNamespace *ns, Error **errp)
{
if (!ns->blkconf.blk) {
error_setg(errp, "block backend not configured");
return -1;
}
return 0;
}
int nvme_ns_setup(NvmeCtrl *n, NvmeNamespace *ns, Error **errp)
{
if (nvme_ns_check_constraints(ns, errp)) {
return -1;
}
if (nvme_ns_init_blk(n, ns, errp)) {
return -1;
}
nvme_ns_init(ns);
if (nvme_register_namespace(n, ns, errp)) {
return -1;
}
return 0;
}
void nvme_ns_drain(NvmeNamespace *ns)
{
blk_drain(ns->blkconf.blk);
}
void nvme_ns_flush(NvmeNamespace *ns)
{
blk_flush(ns->blkconf.blk);
}
static void nvme_ns_realize(DeviceState *dev, Error **errp)
{
NvmeNamespace *ns = NVME_NS(dev);
BusState *s = qdev_get_parent_bus(dev);
NvmeCtrl *n = NVME(s->parent);
Error *local_err = NULL;
if (nvme_ns_setup(n, ns, &local_err)) {
error_propagate_prepend(errp, local_err,
"could not setup namespace: ");
return;
}
}
static Property nvme_ns_props[] = {
DEFINE_BLOCK_PROPERTIES(NvmeNamespace, blkconf),
DEFINE_PROP_UINT32("nsid", NvmeNamespace, params.nsid, 0),
DEFINE_PROP_END_OF_LIST(),
};
static void nvme_ns_class_init(ObjectClass *oc, void *data)
{
DeviceClass *dc = DEVICE_CLASS(oc);
set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
dc->bus_type = TYPE_NVME_BUS;
dc->realize = nvme_ns_realize;
device_class_set_props(dc, nvme_ns_props);
dc->desc = "Virtual NVMe namespace";
}
static void nvme_ns_instance_init(Object *obj)
{
NvmeNamespace *ns = NVME_NS(obj);
char *bootindex = g_strdup_printf("/namespace@%d,0", ns->params.nsid);
device_add_bootindex_property(obj, &ns->bootindex, "bootindex",
bootindex, DEVICE(obj));
g_free(bootindex);
}
static const TypeInfo nvme_ns_info = {
.name = TYPE_NVME_NS,
.parent = TYPE_DEVICE,
.class_init = nvme_ns_class_init,
.instance_size = sizeof(NvmeNamespace),
.instance_init = nvme_ns_instance_init,
};
static void nvme_ns_register_types(void)
{
type_register_static(&nvme_ns_info);
}
type_init(nvme_ns_register_types)