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qemu/block/block-backend.c
Hanna Czenczek ad89367202 block-backend: Allow concurrent context changes 
Since AioContext locks have been removed, a BlockBackend's AioContext
may really change at any time (only exception is that it is often
confined to a drained section, as noted in this patch).  Therefore,
blk_get_aio_context() cannot rely on its root node's context always
matching that of the BlockBackend.

In practice, whether they match does not matter anymore anyway: Requests
can be sent to BDSs from any context, so anyone who requests the BB's
context should have no reason to require the root node to have the same
context.  Therefore, we can and should remove the assertion to that
effect.

In addition, because the context can be set and queried from different
threads concurrently, it has to be accessed with atomic operations.

Buglink: https://issues.redhat.com/browse/RHEL-19381
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Hanna Czenczek <hreitz@redhat.com>
Message-ID: <20240202144755.671354-2-hreitz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2024-02-07 14:55:25 +01:00

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/*
* QEMU Block backends
*
* Copyright (C) 2014-2016 Red Hat, Inc.
*
* Authors:
* Markus Armbruster <armbru@redhat.com>,
*
* This work is licensed under the terms of the GNU LGPL, version 2.1
* or later. See the COPYING.LIB file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "sysemu/block-backend.h"
#include "block/block_int.h"
#include "block/blockjob.h"
#include "block/coroutines.h"
#include "block/throttle-groups.h"
#include "hw/qdev-core.h"
#include "sysemu/blockdev.h"
#include "sysemu/runstate.h"
#include "sysemu/replay.h"
#include "qapi/error.h"
#include "qapi/qapi-events-block.h"
#include "qemu/id.h"
#include "qemu/main-loop.h"
#include "qemu/option.h"
#include "trace.h"
#include "migration/misc.h"
/* Number of coroutines to reserve per attached device model */
#define COROUTINE_POOL_RESERVATION 64
#define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */
typedef struct BlockBackendAioNotifier {
void (*attached_aio_context)(AioContext *new_context, void *opaque);
void (*detach_aio_context)(void *opaque);
void *opaque;
QLIST_ENTRY(BlockBackendAioNotifier) list;
} BlockBackendAioNotifier;
struct BlockBackend {
char *name;
int refcnt;
BdrvChild *root;
AioContext *ctx; /* access with atomic operations only */
DriveInfo *legacy_dinfo; /* null unless created by drive_new() */
QTAILQ_ENTRY(BlockBackend) link; /* for block_backends */
QTAILQ_ENTRY(BlockBackend) monitor_link; /* for monitor_block_backends */
BlockBackendPublic public;
DeviceState *dev; /* attached device model, if any */
const BlockDevOps *dev_ops;
void *dev_opaque;
/* If the BDS tree is removed, some of its options are stored here (which
* can be used to restore those options in the new BDS on insert) */
BlockBackendRootState root_state;
bool enable_write_cache;
/* I/O stats (display with "info blockstats"). */
BlockAcctStats stats;
BlockdevOnError on_read_error, on_write_error;
bool iostatus_enabled;
BlockDeviceIoStatus iostatus;
uint64_t perm;
uint64_t shared_perm;
bool disable_perm;
bool allow_aio_context_change;
bool allow_write_beyond_eof;
/* Protected by BQL */
NotifierList remove_bs_notifiers, insert_bs_notifiers;
QLIST_HEAD(, BlockBackendAioNotifier) aio_notifiers;
int quiesce_counter; /* atomic: written under BQL, read by other threads */
QemuMutex queued_requests_lock; /* protects queued_requests */
CoQueue queued_requests;
bool disable_request_queuing; /* atomic */
VMChangeStateEntry *vmsh;
bool force_allow_inactivate;
/* Number of in-flight aio requests. BlockDriverState also counts
* in-flight requests but aio requests can exist even when blk->root is
* NULL, so we cannot rely on its counter for that case.
* Accessed with atomic ops.
*/
unsigned int in_flight;
};
typedef struct BlockBackendAIOCB {
BlockAIOCB common;
BlockBackend *blk;
int ret;
} BlockBackendAIOCB;
static const AIOCBInfo block_backend_aiocb_info = {
.aiocb_size = sizeof(BlockBackendAIOCB),
};
static void drive_info_del(DriveInfo *dinfo);
static BlockBackend *bdrv_first_blk(BlockDriverState *bs);
/* All BlockBackends. Protected by BQL. */
static QTAILQ_HEAD(, BlockBackend) block_backends =
QTAILQ_HEAD_INITIALIZER(block_backends);
/*
* All BlockBackends referenced by the monitor and which are iterated through by
* blk_next(). Protected by BQL.
*/
static QTAILQ_HEAD(, BlockBackend) monitor_block_backends =
QTAILQ_HEAD_INITIALIZER(monitor_block_backends);
static int coroutine_mixed_fn GRAPH_RDLOCK
blk_set_perm_locked(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
Error **errp);
static void blk_root_inherit_options(BdrvChildRole role, bool parent_is_format,
int *child_flags, QDict *child_options,
int parent_flags, QDict *parent_options)
{
/* We're not supposed to call this function for root nodes */
abort();
}
static void blk_root_drained_begin(BdrvChild *child);
static bool blk_root_drained_poll(BdrvChild *child);
static void blk_root_drained_end(BdrvChild *child);
static void blk_root_change_media(BdrvChild *child, bool load);
static void blk_root_resize(BdrvChild *child);
static bool blk_root_change_aio_ctx(BdrvChild *child, AioContext *ctx,
GHashTable *visited, Transaction *tran,
Error **errp);
static char *blk_root_get_parent_desc(BdrvChild *child)
{
BlockBackend *blk = child->opaque;
g_autofree char *dev_id = NULL;
if (blk->name) {
return g_strdup_printf("block device '%s'", blk->name);
}
dev_id = blk_get_attached_dev_id(blk);
if (*dev_id) {
return g_strdup_printf("block device '%s'", dev_id);
} else {
/* TODO Callback into the BB owner for something more detailed */
return g_strdup("an unnamed block device");
}
}
static const char *blk_root_get_name(BdrvChild *child)
{
return blk_name(child->opaque);
}
static void blk_vm_state_changed(void *opaque, bool running, RunState state)
{
Error *local_err = NULL;
BlockBackend *blk = opaque;
if (state == RUN_STATE_INMIGRATE) {
return;
}
qemu_del_vm_change_state_handler(blk->vmsh);
blk->vmsh = NULL;
blk_set_perm(blk, blk->perm, blk->shared_perm, &local_err);
if (local_err) {
error_report_err(local_err);
}
}
/*
* Notifies the user of the BlockBackend that migration has completed. qdev
* devices can tighten their permissions in response (specifically revoke
* shared write permissions that we needed for storage migration).
*
* If an error is returned, the VM cannot be allowed to be resumed.
*/
static void GRAPH_RDLOCK blk_root_activate(BdrvChild *child, Error **errp)
{
BlockBackend *blk = child->opaque;
Error *local_err = NULL;
uint64_t saved_shared_perm;
if (!blk->disable_perm) {
return;
}
blk->disable_perm = false;
/*
* blk->shared_perm contains the permissions we want to share once
* migration is really completely done. For now, we need to share
* all; but we also need to retain blk->shared_perm, which is
* overwritten by a successful blk_set_perm() call. Save it and
* restore it below.
*/
saved_shared_perm = blk->shared_perm;
blk_set_perm_locked(blk, blk->perm, BLK_PERM_ALL, &local_err);
if (local_err) {
error_propagate(errp, local_err);
blk->disable_perm = true;
return;
}
blk->shared_perm = saved_shared_perm;
if (runstate_check(RUN_STATE_INMIGRATE)) {
/* Activation can happen when migration process is still active, for
* example when nbd_server_add is called during non-shared storage
* migration. Defer the shared_perm update to migration completion. */
if (!blk->vmsh) {
blk->vmsh = qemu_add_vm_change_state_handler(blk_vm_state_changed,
blk);
}
return;
}
blk_set_perm_locked(blk, blk->perm, blk->shared_perm, &local_err);
if (local_err) {
error_propagate(errp, local_err);
blk->disable_perm = true;
return;
}
}
void blk_set_force_allow_inactivate(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
blk->force_allow_inactivate = true;
}
static bool blk_can_inactivate(BlockBackend *blk)
{
/* If it is a guest device, inactivate is ok. */
if (blk->dev || blk_name(blk)[0]) {
return true;
}
/* Inactivating means no more writes to the image can be done,
* even if those writes would be changes invisible to the
* guest. For block job BBs that satisfy this, we can just allow
* it. This is the case for mirror job source, which is required
* by libvirt non-shared block migration. */
if (!(blk->perm & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED))) {
return true;
}
return blk->force_allow_inactivate;
}
static int GRAPH_RDLOCK blk_root_inactivate(BdrvChild *child)
{
BlockBackend *blk = child->opaque;
if (blk->disable_perm) {
return 0;
}
if (!blk_can_inactivate(blk)) {
return -EPERM;
}
blk->disable_perm = true;
if (blk->root) {
bdrv_child_try_set_perm(blk->root, 0, BLK_PERM_ALL, &error_abort);
}
return 0;
}
static void blk_root_attach(BdrvChild *child)
{
BlockBackend *blk = child->opaque;
BlockBackendAioNotifier *notifier;
trace_blk_root_attach(child, blk, child->bs);
QLIST_FOREACH(notifier, &blk->aio_notifiers, list) {
bdrv_add_aio_context_notifier(child->bs,
notifier->attached_aio_context,
notifier->detach_aio_context,
notifier->opaque);
}
}
static void blk_root_detach(BdrvChild *child)
{
BlockBackend *blk = child->opaque;
BlockBackendAioNotifier *notifier;
trace_blk_root_detach(child, blk, child->bs);
QLIST_FOREACH(notifier, &blk->aio_notifiers, list) {
bdrv_remove_aio_context_notifier(child->bs,
notifier->attached_aio_context,
notifier->detach_aio_context,
notifier->opaque);
}
}
static AioContext *blk_root_get_parent_aio_context(BdrvChild *c)
{
BlockBackend *blk = c->opaque;
IO_CODE();
return blk_get_aio_context(blk);
}
static const BdrvChildClass child_root = {
.inherit_options = blk_root_inherit_options,
.change_media = blk_root_change_media,
.resize = blk_root_resize,
.get_name = blk_root_get_name,
.get_parent_desc = blk_root_get_parent_desc,
.drained_begin = blk_root_drained_begin,
.drained_poll = blk_root_drained_poll,
.drained_end = blk_root_drained_end,
.activate = blk_root_activate,
.inactivate = blk_root_inactivate,
.attach = blk_root_attach,
.detach = blk_root_detach,
.change_aio_ctx = blk_root_change_aio_ctx,
.get_parent_aio_context = blk_root_get_parent_aio_context,
};
/*
* Create a new BlockBackend with a reference count of one.
*
* @perm is a bitmasks of BLK_PERM_* constants which describes the permissions
* to request for a block driver node that is attached to this BlockBackend.
* @shared_perm is a bitmask which describes which permissions may be granted
* to other users of the attached node.
* Both sets of permissions can be changed later using blk_set_perm().
*
* Return the new BlockBackend on success, null on failure.
*/
BlockBackend *blk_new(AioContext *ctx, uint64_t perm, uint64_t shared_perm)
{
BlockBackend *blk;
GLOBAL_STATE_CODE();
blk = g_new0(BlockBackend, 1);
blk->refcnt = 1;
blk->ctx = ctx;
blk->perm = perm;
blk->shared_perm = shared_perm;
blk_set_enable_write_cache(blk, true);
blk->on_read_error = BLOCKDEV_ON_ERROR_REPORT;
blk->on_write_error = BLOCKDEV_ON_ERROR_ENOSPC;
block_acct_init(&blk->stats);
qemu_mutex_init(&blk->queued_requests_lock);
qemu_co_queue_init(&blk->queued_requests);
notifier_list_init(&blk->remove_bs_notifiers);
notifier_list_init(&blk->insert_bs_notifiers);
QLIST_INIT(&blk->aio_notifiers);
QTAILQ_INSERT_TAIL(&block_backends, blk, link);
return blk;
}
/*
* Create a new BlockBackend connected to an existing BlockDriverState.
*
* @perm is a bitmasks of BLK_PERM_* constants which describes the
* permissions to request for @bs that is attached to this
* BlockBackend. @shared_perm is a bitmask which describes which
* permissions may be granted to other users of the attached node.
* Both sets of permissions can be changed later using blk_set_perm().
*
* Return the new BlockBackend on success, null on failure.
*/
BlockBackend *blk_new_with_bs(BlockDriverState *bs, uint64_t perm,
uint64_t shared_perm, Error **errp)
{
BlockBackend *blk = blk_new(bdrv_get_aio_context(bs), perm, shared_perm);
GLOBAL_STATE_CODE();
if (blk_insert_bs(blk, bs, errp) < 0) {
blk_unref(blk);
return NULL;
}
return blk;
}
/*
* Creates a new BlockBackend, opens a new BlockDriverState, and connects both.
* By default, the new BlockBackend is in the main AioContext, but if the
* parameters connect it with any existing node in a different AioContext, it
* may end up there instead.
*
* Just as with bdrv_open(), after having called this function the reference to
* @options belongs to the block layer (even on failure).
*
* TODO: Remove @filename and @flags; it should be possible to specify a whole
* BDS tree just by specifying the @options QDict (or @reference,
* alternatively). At the time of adding this function, this is not possible,
* though, so callers of this function have to be able to specify @filename and
* @flags.
*/
BlockBackend *blk_new_open(const char *filename, const char *reference,
QDict *options, int flags, Error **errp)
{
BlockBackend *blk;
BlockDriverState *bs;
uint64_t perm = 0;
uint64_t shared = BLK_PERM_ALL;
GLOBAL_STATE_CODE();
/*
* blk_new_open() is mainly used in .bdrv_create implementations and the
* tools where sharing isn't a major concern because the BDS stays private
* and the file is generally not supposed to be used by a second process,
* so we just request permission according to the flags.
*
* The exceptions are xen_disk and blockdev_init(); in these cases, the
* caller of blk_new_open() doesn't make use of the permissions, but they
* shouldn't hurt either. We can still share everything here because the
* guest devices will add their own blockers if they can't share.
*/
if ((flags & BDRV_O_NO_IO) == 0) {
perm |= BLK_PERM_CONSISTENT_READ;
if (flags & BDRV_O_RDWR) {
perm |= BLK_PERM_WRITE;
}
}
if (flags & BDRV_O_RESIZE) {
perm |= BLK_PERM_RESIZE;
}
if (flags & BDRV_O_NO_SHARE) {
shared = BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE_UNCHANGED;
}
bs = bdrv_open(filename, reference, options, flags, errp);
if (!bs) {
return NULL;
}
/* bdrv_open() could have moved bs to a different AioContext */
blk = blk_new(bdrv_get_aio_context(bs), perm, shared);
blk->perm = perm;
blk->shared_perm = shared;
blk_insert_bs(blk, bs, errp);
bdrv_unref(bs);
if (!blk->root) {
blk_unref(blk);
return NULL;
}
return blk;
}
static void blk_delete(BlockBackend *blk)
{
assert(!blk->refcnt);
assert(!blk->name);
assert(!blk->dev);
if (blk->public.throttle_group_member.throttle_state) {
blk_io_limits_disable(blk);
}
if (blk->root) {
blk_remove_bs(blk);
}
if (blk->vmsh) {
qemu_del_vm_change_state_handler(blk->vmsh);
blk->vmsh = NULL;
}
assert(QLIST_EMPTY(&blk->remove_bs_notifiers.notifiers));
assert(QLIST_EMPTY(&blk->insert_bs_notifiers.notifiers));
assert(QLIST_EMPTY(&blk->aio_notifiers));
assert(qemu_co_queue_empty(&blk->queued_requests));
qemu_mutex_destroy(&blk->queued_requests_lock);
QTAILQ_REMOVE(&block_backends, blk, link);
drive_info_del(blk->legacy_dinfo);
block_acct_cleanup(&blk->stats);
g_free(blk);
}
static void drive_info_del(DriveInfo *dinfo)
{
if (!dinfo) {
return;
}
qemu_opts_del(dinfo->opts);
g_free(dinfo);
}
int blk_get_refcnt(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return blk ? blk->refcnt : 0;
}
/*
* Increment @blk's reference count.
* @blk must not be null.
*/
void blk_ref(BlockBackend *blk)
{
assert(blk->refcnt > 0);
GLOBAL_STATE_CODE();
blk->refcnt++;
}
/*
* Decrement @blk's reference count.
* If this drops it to zero, destroy @blk.
* For convenience, do nothing if @blk is null.
*/
void blk_unref(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
if (blk) {
assert(blk->refcnt > 0);
if (blk->refcnt > 1) {
blk->refcnt--;
} else {
blk_drain(blk);
/* blk_drain() cannot resurrect blk, nobody held a reference */
assert(blk->refcnt == 1);
blk->refcnt = 0;
blk_delete(blk);
}
}
}
/*
* Behaves similarly to blk_next() but iterates over all BlockBackends, even the
* ones which are hidden (i.e. are not referenced by the monitor).
*/
BlockBackend *blk_all_next(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return blk ? QTAILQ_NEXT(blk, link)
: QTAILQ_FIRST(&block_backends);
}
void blk_remove_all_bs(void)
{
BlockBackend *blk = NULL;
GLOBAL_STATE_CODE();
while ((blk = blk_all_next(blk)) != NULL) {
if (blk->root) {
blk_remove_bs(blk);
}
}
}
/*
* Return the monitor-owned BlockBackend after @blk.
* If @blk is null, return the first one.
* Else, return @blk's next sibling, which may be null.
*
* To iterate over all BlockBackends, do
* for (blk = blk_next(NULL); blk; blk = blk_next(blk)) {
* ...
* }
*/
BlockBackend *blk_next(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return blk ? QTAILQ_NEXT(blk, monitor_link)
: QTAILQ_FIRST(&monitor_block_backends);
}
/* Iterates over all top-level BlockDriverStates, i.e. BDSs that are owned by
* the monitor or attached to a BlockBackend */
BlockDriverState *bdrv_next(BdrvNextIterator *it)
{
BlockDriverState *bs, *old_bs;
/* Must be called from the main loop */
assert(qemu_get_current_aio_context() == qemu_get_aio_context());
/* First, return all root nodes of BlockBackends. In order to avoid
* returning a BDS twice when multiple BBs refer to it, we only return it
* if the BB is the first one in the parent list of the BDS. */
if (it->phase == BDRV_NEXT_BACKEND_ROOTS) {
BlockBackend *old_blk = it->blk;
old_bs = old_blk ? blk_bs(old_blk) : NULL;
do {
it->blk = blk_all_next(it->blk);
bs = it->blk ? blk_bs(it->blk) : NULL;
} while (it->blk && (bs == NULL || bdrv_first_blk(bs) != it->blk));
if (it->blk) {
blk_ref(it->blk);
}
blk_unref(old_blk);
if (bs) {
bdrv_ref(bs);
bdrv_unref(old_bs);
return bs;
}
it->phase = BDRV_NEXT_MONITOR_OWNED;
} else {
old_bs = it->bs;
}
/* Then return the monitor-owned BDSes without a BB attached. Ignore all
* BDSes that are attached to a BlockBackend here; they have been handled
* by the above block already */
do {
it->bs = bdrv_next_monitor_owned(it->bs);
bs = it->bs;
} while (bs && bdrv_has_blk(bs));
if (bs) {
bdrv_ref(bs);
}
bdrv_unref(old_bs);
return bs;
}
static void bdrv_next_reset(BdrvNextIterator *it)
{
*it = (BdrvNextIterator) {
.phase = BDRV_NEXT_BACKEND_ROOTS,
};
}
BlockDriverState *bdrv_first(BdrvNextIterator *it)
{
GLOBAL_STATE_CODE();
bdrv_next_reset(it);
return bdrv_next(it);
}
/* Must be called when aborting a bdrv_next() iteration before
* bdrv_next() returns NULL */
void bdrv_next_cleanup(BdrvNextIterator *it)
{
/* Must be called from the main loop */
assert(qemu_get_current_aio_context() == qemu_get_aio_context());
if (it->phase == BDRV_NEXT_BACKEND_ROOTS) {
if (it->blk) {
bdrv_unref(blk_bs(it->blk));
blk_unref(it->blk);
}
} else {
bdrv_unref(it->bs);
}
bdrv_next_reset(it);
}
/*
* Add a BlockBackend into the list of backends referenced by the monitor, with
* the given @name acting as the handle for the monitor.
* Strictly for use by blockdev.c.
*
* @name must not be null or empty.
*
* Returns true on success and false on failure. In the latter case, an Error
* object is returned through @errp.
*/
bool monitor_add_blk(BlockBackend *blk, const char *name, Error **errp)
{
assert(!blk->name);
assert(name && name[0]);
GLOBAL_STATE_CODE();
if (!id_wellformed(name)) {
error_setg(errp, "Invalid device name");
return false;
}
if (blk_by_name(name)) {
error_setg(errp, "Device with id '%s' already exists", name);
return false;
}
if (bdrv_find_node(name)) {
error_setg(errp,
"Device name '%s' conflicts with an existing node name",
name);
return false;
}
blk->name = g_strdup(name);
QTAILQ_INSERT_TAIL(&monitor_block_backends, blk, monitor_link);
return true;
}
/*
* Remove a BlockBackend from the list of backends referenced by the monitor.
* Strictly for use by blockdev.c.
*/
void monitor_remove_blk(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
if (!blk->name) {
return;
}
QTAILQ_REMOVE(&monitor_block_backends, blk, monitor_link);
g_free(blk->name);
blk->name = NULL;
}
/*
* Return @blk's name, a non-null string.
* Returns an empty string iff @blk is not referenced by the monitor.
*/
const char *blk_name(const BlockBackend *blk)
{
IO_CODE();
return blk->name ?: "";
}
/*
* Return the BlockBackend with name @name if it exists, else null.
* @name must not be null.
*/
BlockBackend *blk_by_name(const char *name)
{
BlockBackend *blk = NULL;
GLOBAL_STATE_CODE();
assert(name);
while ((blk = blk_next(blk)) != NULL) {
if (!strcmp(name, blk->name)) {
return blk;
}
}
return NULL;
}
/*
* Return the BlockDriverState attached to @blk if any, else null.
*/
BlockDriverState *blk_bs(BlockBackend *blk)
{
IO_CODE();
return blk->root ? blk->root->bs : NULL;
}
static BlockBackend * GRAPH_RDLOCK bdrv_first_blk(BlockDriverState *bs)
{
BdrvChild *child;
GLOBAL_STATE_CODE();
assert_bdrv_graph_readable();
QLIST_FOREACH(child, &bs->parents, next_parent) {
if (child->klass == &child_root) {
return child->opaque;
}
}
return NULL;
}
/*
* Returns true if @bs has an associated BlockBackend.
*/
bool bdrv_has_blk(BlockDriverState *bs)
{
GLOBAL_STATE_CODE();
return bdrv_first_blk(bs) != NULL;
}
/*
* Returns true if @bs has only BlockBackends as parents.
*/
bool bdrv_is_root_node(BlockDriverState *bs)
{
BdrvChild *c;
GLOBAL_STATE_CODE();
assert_bdrv_graph_readable();
QLIST_FOREACH(c, &bs->parents, next_parent) {
if (c->klass != &child_root) {
return false;
}
}
return true;
}
/*
* Return @blk's DriveInfo if any, else null.
*/
DriveInfo *blk_legacy_dinfo(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return blk->legacy_dinfo;
}
/*
* Set @blk's DriveInfo to @dinfo, and return it.
* @blk must not have a DriveInfo set already.
* No other BlockBackend may have the same DriveInfo set.
*/
DriveInfo *blk_set_legacy_dinfo(BlockBackend *blk, DriveInfo *dinfo)
{
assert(!blk->legacy_dinfo);
GLOBAL_STATE_CODE();
return blk->legacy_dinfo = dinfo;
}
/*
* Return the BlockBackend with DriveInfo @dinfo.
* It must exist.
*/
BlockBackend *blk_by_legacy_dinfo(DriveInfo *dinfo)
{
BlockBackend *blk = NULL;
GLOBAL_STATE_CODE();
while ((blk = blk_next(blk)) != NULL) {
if (blk->legacy_dinfo == dinfo) {
return blk;
}
}
abort();
}
/*
* Returns a pointer to the publicly accessible fields of @blk.
*/
BlockBackendPublic *blk_get_public(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return &blk->public;
}
/*
* Returns a BlockBackend given the associated @public fields.
*/
BlockBackend *blk_by_public(BlockBackendPublic *public)
{
GLOBAL_STATE_CODE();
return container_of(public, BlockBackend, public);
}
/*
* Disassociates the currently associated BlockDriverState from @blk.
*/
void blk_remove_bs(BlockBackend *blk)
{
ThrottleGroupMember *tgm = &blk->public.throttle_group_member;
BdrvChild *root;
GLOBAL_STATE_CODE();
notifier_list_notify(&blk->remove_bs_notifiers, blk);
if (tgm->throttle_state) {
BlockDriverState *bs = blk_bs(blk);
/*
* Take a ref in case blk_bs() changes across bdrv_drained_begin(), for
* example, if a temporary filter node is removed by a blockjob.
*/
bdrv_ref(bs);
bdrv_drained_begin(bs);
throttle_group_detach_aio_context(tgm);
throttle_group_attach_aio_context(tgm, qemu_get_aio_context());
bdrv_drained_end(bs);
bdrv_unref(bs);
}
blk_update_root_state(blk);
/* bdrv_root_unref_child() will cause blk->root to become stale and may
* switch to a completion coroutine later on. Let's drain all I/O here
* to avoid that and a potential QEMU crash.
*/
blk_drain(blk);
root = blk->root;
blk->root = NULL;
bdrv_graph_wrlock();
bdrv_root_unref_child(root);
bdrv_graph_wrunlock();
}
/*
* Associates a new BlockDriverState with @blk.
*/
int blk_insert_bs(BlockBackend *blk, BlockDriverState *bs, Error **errp)
{
ThrottleGroupMember *tgm = &blk->public.throttle_group_member;
GLOBAL_STATE_CODE();
bdrv_ref(bs);
bdrv_graph_wrlock();
blk->root = bdrv_root_attach_child(bs, "root", &child_root,
BDRV_CHILD_FILTERED | BDRV_CHILD_PRIMARY,
blk->perm, blk->shared_perm,
blk, errp);
bdrv_graph_wrunlock();
if (blk->root == NULL) {
return -EPERM;
}
notifier_list_notify(&blk->insert_bs_notifiers, blk);
if (tgm->throttle_state) {
throttle_group_detach_aio_context(tgm);
throttle_group_attach_aio_context(tgm, bdrv_get_aio_context(bs));
}
return 0;
}
/*
* Change BlockDriverState associated with @blk.
*/
int blk_replace_bs(BlockBackend *blk, BlockDriverState *new_bs, Error **errp)
{
GLOBAL_STATE_CODE();
return bdrv_replace_child_bs(blk->root, new_bs, errp);
}
/*
* Sets the permission bitmasks that the user of the BlockBackend needs.
*/
static int coroutine_mixed_fn GRAPH_RDLOCK
blk_set_perm_locked(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
Error **errp)
{
int ret;
GLOBAL_STATE_CODE();
if (blk->root && !blk->disable_perm) {
ret = bdrv_child_try_set_perm(blk->root, perm, shared_perm, errp);
if (ret < 0) {
return ret;
}
}
blk->perm = perm;
blk->shared_perm = shared_perm;
return 0;
}
int blk_set_perm(BlockBackend *blk, uint64_t perm, uint64_t shared_perm,
Error **errp)
{
GLOBAL_STATE_CODE();
GRAPH_RDLOCK_GUARD_MAINLOOP();
return blk_set_perm_locked(blk, perm, shared_perm, errp);
}
void blk_get_perm(BlockBackend *blk, uint64_t *perm, uint64_t *shared_perm)
{
GLOBAL_STATE_CODE();
*perm = blk->perm;
*shared_perm = blk->shared_perm;
}
/*
* Attach device model @dev to @blk.
* Return 0 on success, -EBUSY when a device model is attached already.
*/
int blk_attach_dev(BlockBackend *blk, DeviceState *dev)
{
GLOBAL_STATE_CODE();
if (blk->dev) {
return -EBUSY;
}
/* While migration is still incoming, we don't need to apply the
* permissions of guest device BlockBackends. We might still have a block
* job or NBD server writing to the image for storage migration. */
if (runstate_check(RUN_STATE_INMIGRATE)) {
blk->disable_perm = true;
}
blk_ref(blk);
blk->dev = dev;
blk_iostatus_reset(blk);
return 0;
}
/*
* Detach device model @dev from @blk.
* @dev must be currently attached to @blk.
*/
void blk_detach_dev(BlockBackend *blk, DeviceState *dev)
{
assert(blk->dev == dev);
GLOBAL_STATE_CODE();
blk->dev = NULL;
blk->dev_ops = NULL;
blk->dev_opaque = NULL;
blk_set_perm(blk, 0, BLK_PERM_ALL, &error_abort);
blk_unref(blk);
}
/*
* Return the device model attached to @blk if any, else null.
*/
DeviceState *blk_get_attached_dev(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return blk->dev;
}
/* Return the qdev ID, or if no ID is assigned the QOM path, of the block
* device attached to the BlockBackend. */
char *blk_get_attached_dev_id(BlockBackend *blk)
{
DeviceState *dev = blk->dev;
IO_CODE();
if (!dev) {
return g_strdup("");
} else if (dev->id) {
return g_strdup(dev->id);
}
return object_get_canonical_path(OBJECT(dev)) ?: g_strdup("");
}
/*
* Return the BlockBackend which has the device model @dev attached if it
* exists, else null.
*
* @dev must not be null.
*/
BlockBackend *blk_by_dev(void *dev)
{
BlockBackend *blk = NULL;
GLOBAL_STATE_CODE();
assert(dev != NULL);
while ((blk = blk_all_next(blk)) != NULL) {
if (blk->dev == dev) {
return blk;
}
}
return NULL;
}
/*
* Set @blk's device model callbacks to @ops.
* @opaque is the opaque argument to pass to the callbacks.
* This is for use by device models.
*/
void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops,
void *opaque)
{
GLOBAL_STATE_CODE();
blk->dev_ops = ops;
blk->dev_opaque = opaque;
/* Are we currently quiesced? Should we enforce this right now? */
if (qatomic_read(&blk->quiesce_counter) && ops && ops->drained_begin) {
ops->drained_begin(opaque);
}
}
/*
* Notify @blk's attached device model of media change.
*
* If @load is true, notify of media load. This action can fail, meaning that
* the medium cannot be loaded. @errp is set then.
*
* If @load is false, notify of media eject. This can never fail.
*
* Also send DEVICE_TRAY_MOVED events as appropriate.
*/
void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp)
{
GLOBAL_STATE_CODE();
if (blk->dev_ops && blk->dev_ops->change_media_cb) {
bool tray_was_open, tray_is_open;
Error *local_err = NULL;
tray_was_open = blk_dev_is_tray_open(blk);
blk->dev_ops->change_media_cb(blk->dev_opaque, load, &local_err);
if (local_err) {
assert(load == true);
error_propagate(errp, local_err);
return;
}
tray_is_open = blk_dev_is_tray_open(blk);
if (tray_was_open != tray_is_open) {
char *id = blk_get_attached_dev_id(blk);
qapi_event_send_device_tray_moved(blk_name(blk), id, tray_is_open);
g_free(id);
}
}
}
static void blk_root_change_media(BdrvChild *child, bool load)
{
blk_dev_change_media_cb(child->opaque, load, NULL);
}
/*
* Does @blk's attached device model have removable media?
* %true if no device model is attached.
*/
bool blk_dev_has_removable_media(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return !blk->dev || (blk->dev_ops && blk->dev_ops->change_media_cb);
}
/*
* Does @blk's attached device model have a tray?
*/
bool blk_dev_has_tray(BlockBackend *blk)
{
IO_CODE();
return blk->dev_ops && blk->dev_ops->is_tray_open;
}
/*
* Notify @blk's attached device model of a media eject request.
* If @force is true, the medium is about to be yanked out forcefully.
*/
void blk_dev_eject_request(BlockBackend *blk, bool force)
{
GLOBAL_STATE_CODE();
if (blk->dev_ops && blk->dev_ops->eject_request_cb) {
blk->dev_ops->eject_request_cb(blk->dev_opaque, force);
}
}
/*
* Does @blk's attached device model have a tray, and is it open?
*/
bool blk_dev_is_tray_open(BlockBackend *blk)
{
IO_CODE();
if (blk_dev_has_tray(blk)) {
return blk->dev_ops->is_tray_open(blk->dev_opaque);
}
return false;
}
/*
* Does @blk's attached device model have the medium locked?
* %false if the device model has no such lock.
*/
bool blk_dev_is_medium_locked(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
if (blk->dev_ops && blk->dev_ops->is_medium_locked) {
return blk->dev_ops->is_medium_locked(blk->dev_opaque);
}
return false;
}
/*
* Notify @blk's attached device model of a backend size change.
*/
static void blk_root_resize(BdrvChild *child)
{
BlockBackend *blk = child->opaque;
if (blk->dev_ops && blk->dev_ops->resize_cb) {
blk->dev_ops->resize_cb(blk->dev_opaque);
}
}
void blk_iostatus_enable(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
blk->iostatus_enabled = true;
blk->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
}
/* The I/O status is only enabled if the drive explicitly
* enables it _and_ the VM is configured to stop on errors */
bool blk_iostatus_is_enabled(const BlockBackend *blk)
{
IO_CODE();
return (blk->iostatus_enabled &&
(blk->on_write_error == BLOCKDEV_ON_ERROR_ENOSPC ||
blk->on_write_error == BLOCKDEV_ON_ERROR_STOP ||
blk->on_read_error == BLOCKDEV_ON_ERROR_STOP));
}
BlockDeviceIoStatus blk_iostatus(const BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return blk->iostatus;
}
void blk_iostatus_disable(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
blk->iostatus_enabled = false;
}
void blk_iostatus_reset(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
if (blk_iostatus_is_enabled(blk)) {
blk->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
}
}
void blk_iostatus_set_err(BlockBackend *blk, int error)
{
IO_CODE();
assert(blk_iostatus_is_enabled(blk));
if (blk->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
blk->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
BLOCK_DEVICE_IO_STATUS_FAILED;
}
}
void blk_set_allow_write_beyond_eof(BlockBackend *blk, bool allow)
{
IO_CODE();
blk->allow_write_beyond_eof = allow;
}
void blk_set_allow_aio_context_change(BlockBackend *blk, bool allow)
{
IO_CODE();
blk->allow_aio_context_change = allow;
}
void blk_set_disable_request_queuing(BlockBackend *blk, bool disable)
{
IO_CODE();
qatomic_set(&blk->disable_request_queuing, disable);
}
static int coroutine_fn GRAPH_RDLOCK
blk_check_byte_request(BlockBackend *blk, int64_t offset, int64_t bytes)
{
int64_t len;
if (bytes < 0) {
return -EIO;
}
if (!blk_co_is_available(blk)) {
return -ENOMEDIUM;
}
if (offset < 0) {
return -EIO;
}
if (!blk->allow_write_beyond_eof) {
len = bdrv_co_getlength(blk_bs(blk));
if (len < 0) {
return len;
}
if (offset > len || len - offset < bytes) {
return -EIO;
}
}
return 0;
}
/* Are we currently in a drained section? */
bool blk_in_drain(BlockBackend *blk)
{
GLOBAL_STATE_CODE(); /* change to IO_OR_GS_CODE(), if necessary */
return qatomic_read(&blk->quiesce_counter);
}
/* To be called between exactly one pair of blk_inc/dec_in_flight() */
static void coroutine_fn blk_wait_while_drained(BlockBackend *blk)
{
assert(blk->in_flight > 0);
if (qatomic_read(&blk->quiesce_counter) &&
!qatomic_read(&blk->disable_request_queuing)) {
/*
* Take lock before decrementing in flight counter so main loop thread
* waits for us to enqueue ourselves before it can leave the drained
* section.
*/
qemu_mutex_lock(&blk->queued_requests_lock);
blk_dec_in_flight(blk);
qemu_co_queue_wait(&blk->queued_requests, &blk->queued_requests_lock);
blk_inc_in_flight(blk);
qemu_mutex_unlock(&blk->queued_requests_lock);
}
}
/* To be called between exactly one pair of blk_inc/dec_in_flight() */
static int coroutine_fn
blk_co_do_preadv_part(BlockBackend *blk, int64_t offset, int64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset,
BdrvRequestFlags flags)
{
int ret;
BlockDriverState *bs;
IO_CODE();
blk_wait_while_drained(blk);
GRAPH_RDLOCK_GUARD();
/* Call blk_bs() only after waiting, the graph may have changed */
bs = blk_bs(blk);
trace_blk_co_preadv(blk, bs, offset, bytes, flags);
ret = blk_check_byte_request(blk, offset, bytes);
if (ret < 0) {
return ret;
}
bdrv_inc_in_flight(bs);
/* throttling disk I/O */
if (blk->public.throttle_group_member.throttle_state) {
throttle_group_co_io_limits_intercept(&blk->public.throttle_group_member,
bytes, THROTTLE_READ);
}
ret = bdrv_co_preadv_part(blk->root, offset, bytes, qiov, qiov_offset,
flags);
bdrv_dec_in_flight(bs);
return ret;
}
int coroutine_fn blk_co_pread(BlockBackend *blk, int64_t offset, int64_t bytes,
void *buf, BdrvRequestFlags flags)
{
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
IO_OR_GS_CODE();
assert(bytes <= SIZE_MAX);
return blk_co_preadv(blk, offset, bytes, &qiov, flags);
}
int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
int64_t bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags)
{
int ret;
IO_OR_GS_CODE();
blk_inc_in_flight(blk);
ret = blk_co_do_preadv_part(blk, offset, bytes, qiov, 0, flags);
blk_dec_in_flight(blk);
return ret;
}
int coroutine_fn blk_co_preadv_part(BlockBackend *blk, int64_t offset,
int64_t bytes, QEMUIOVector *qiov,
size_t qiov_offset, BdrvRequestFlags flags)
{
int ret;
IO_OR_GS_CODE();
blk_inc_in_flight(blk);
ret = blk_co_do_preadv_part(blk, offset, bytes, qiov, qiov_offset, flags);
blk_dec_in_flight(blk);
return ret;
}
/* To be called between exactly one pair of blk_inc/dec_in_flight() */
static int coroutine_fn
blk_co_do_pwritev_part(BlockBackend *blk, int64_t offset, int64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset,
BdrvRequestFlags flags)
{
int ret;
BlockDriverState *bs;
IO_CODE();
blk_wait_while_drained(blk);
GRAPH_RDLOCK_GUARD();
/* Call blk_bs() only after waiting, the graph may have changed */
bs = blk_bs(blk);
trace_blk_co_pwritev(blk, bs, offset, bytes, flags);
ret = blk_check_byte_request(blk, offset, bytes);
if (ret < 0) {
return ret;
}
bdrv_inc_in_flight(bs);
/* throttling disk I/O */
if (blk->public.throttle_group_member.throttle_state) {
throttle_group_co_io_limits_intercept(&blk->public.throttle_group_member,
bytes, THROTTLE_WRITE);
}
if (!blk->enable_write_cache) {
flags |= BDRV_REQ_FUA;
}
ret = bdrv_co_pwritev_part(blk->root, offset, bytes, qiov, qiov_offset,
flags);
bdrv_dec_in_flight(bs);
return ret;
}
int coroutine_fn blk_co_pwritev_part(BlockBackend *blk, int64_t offset,
int64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset,
BdrvRequestFlags flags)
{
int ret;
IO_OR_GS_CODE();
blk_inc_in_flight(blk);
ret = blk_co_do_pwritev_part(blk, offset, bytes, qiov, qiov_offset, flags);
blk_dec_in_flight(blk);
return ret;
}
int coroutine_fn blk_co_pwrite(BlockBackend *blk, int64_t offset, int64_t bytes,
const void *buf, BdrvRequestFlags flags)
{
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
IO_OR_GS_CODE();
assert(bytes <= SIZE_MAX);
return blk_co_pwritev(blk, offset, bytes, &qiov, flags);
}
int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
int64_t bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags)
{
IO_OR_GS_CODE();
return blk_co_pwritev_part(blk, offset, bytes, qiov, 0, flags);
}
int coroutine_fn blk_co_block_status_above(BlockBackend *blk,
BlockDriverState *base,
int64_t offset, int64_t bytes,
int64_t *pnum, int64_t *map,
BlockDriverState **file)
{
IO_CODE();
GRAPH_RDLOCK_GUARD();
return bdrv_co_block_status_above(blk_bs(blk), base, offset, bytes, pnum,
map, file);
}
int coroutine_fn blk_co_is_allocated_above(BlockBackend *blk,
BlockDriverState *base,
bool include_base, int64_t offset,
int64_t bytes, int64_t *pnum)
{
IO_CODE();
GRAPH_RDLOCK_GUARD();
return bdrv_co_is_allocated_above(blk_bs(blk), base, include_base, offset,
bytes, pnum);
}
typedef struct BlkRwCo {
BlockBackend *blk;
int64_t offset;
void *iobuf;
int ret;
BdrvRequestFlags flags;
} BlkRwCo;
int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags)
{
GLOBAL_STATE_CODE();
return bdrv_make_zero(blk->root, flags);
}
void blk_inc_in_flight(BlockBackend *blk)
{
IO_CODE();
qatomic_inc(&blk->in_flight);
}
void blk_dec_in_flight(BlockBackend *blk)
{
IO_CODE();
qatomic_dec(&blk->in_flight);
aio_wait_kick();
}
static void error_callback_bh(void *opaque)
{
struct BlockBackendAIOCB *acb = opaque;
blk_dec_in_flight(acb->blk);
acb->common.cb(acb->common.opaque, acb->ret);
qemu_aio_unref(acb);
}
BlockAIOCB *blk_abort_aio_request(BlockBackend *blk,
BlockCompletionFunc *cb,
void *opaque, int ret)
{
struct BlockBackendAIOCB *acb;
IO_CODE();
blk_inc_in_flight(blk);
acb = blk_aio_get(&block_backend_aiocb_info, blk, cb, opaque);
acb->blk = blk;
acb->ret = ret;
replay_bh_schedule_oneshot_event(qemu_get_current_aio_context(),
error_callback_bh, acb);
return &acb->common;
}
typedef struct BlkAioEmAIOCB {
BlockAIOCB common;
BlkRwCo rwco;
int64_t bytes;
bool has_returned;
} BlkAioEmAIOCB;
static const AIOCBInfo blk_aio_em_aiocb_info = {
.aiocb_size = sizeof(BlkAioEmAIOCB),
};
static void blk_aio_complete(BlkAioEmAIOCB *acb)
{
if (acb->has_returned) {
acb->common.cb(acb->common.opaque, acb->rwco.ret);
blk_dec_in_flight(acb->rwco.blk);
qemu_aio_unref(acb);
}
}
static void blk_aio_complete_bh(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
assert(acb->has_returned);
blk_aio_complete(acb);
}
static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset,
int64_t bytes,
void *iobuf, CoroutineEntry co_entry,
BdrvRequestFlags flags,
BlockCompletionFunc *cb, void *opaque)
{
BlkAioEmAIOCB *acb;
Coroutine *co;
blk_inc_in_flight(blk);
acb = blk_aio_get(&blk_aio_em_aiocb_info, blk, cb, opaque);
acb->rwco = (BlkRwCo) {
.blk = blk,
.offset = offset,
.iobuf = iobuf,
.flags = flags,
.ret = NOT_DONE,
};
acb->bytes = bytes;
acb->has_returned = false;
co = qemu_coroutine_create(co_entry, acb);
aio_co_enter(qemu_get_current_aio_context(), co);
acb->has_returned = true;
if (acb->rwco.ret != NOT_DONE) {
replay_bh_schedule_oneshot_event(qemu_get_current_aio_context(),
blk_aio_complete_bh, acb);
}
return &acb->common;
}
static void coroutine_fn blk_aio_read_entry(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
BlkRwCo *rwco = &acb->rwco;
QEMUIOVector *qiov = rwco->iobuf;
assert(qiov->size == acb->bytes);
rwco->ret = blk_co_do_preadv_part(rwco->blk, rwco->offset, acb->bytes, qiov,
0, rwco->flags);
blk_aio_complete(acb);
}
static void coroutine_fn blk_aio_write_entry(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
BlkRwCo *rwco = &acb->rwco;
QEMUIOVector *qiov = rwco->iobuf;
assert(!qiov || qiov->size == acb->bytes);
rwco->ret = blk_co_do_pwritev_part(rwco->blk, rwco->offset, acb->bytes,
qiov, 0, rwco->flags);
blk_aio_complete(acb);
}
BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
int64_t bytes, BdrvRequestFlags flags,
BlockCompletionFunc *cb, void *opaque)
{
IO_CODE();
return blk_aio_prwv(blk, offset, bytes, NULL, blk_aio_write_entry,
flags | BDRV_REQ_ZERO_WRITE, cb, opaque);
}
int64_t coroutine_fn blk_co_getlength(BlockBackend *blk)
{
IO_CODE();
GRAPH_RDLOCK_GUARD();
if (!blk_co_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_co_getlength(blk_bs(blk));
}
int64_t coroutine_fn blk_co_nb_sectors(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
IO_CODE();
GRAPH_RDLOCK_GUARD();
if (!bs) {
return -ENOMEDIUM;
} else {
return bdrv_co_nb_sectors(bs);
}
}
/*
* This wrapper is written by hand because this function is in the hot I/O path,
* via blk_get_geometry.
*/
int64_t coroutine_mixed_fn blk_nb_sectors(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
IO_CODE();
if (!bs) {
return -ENOMEDIUM;
} else {
return bdrv_nb_sectors(bs);
}
}
/* return 0 as number of sectors if no device present or error */
void coroutine_fn blk_co_get_geometry(BlockBackend *blk,
uint64_t *nb_sectors_ptr)
{
int64_t ret = blk_co_nb_sectors(blk);
*nb_sectors_ptr = ret < 0 ? 0 : ret;
}
/*
* This wrapper is written by hand because this function is in the hot I/O path.
*/
void coroutine_mixed_fn blk_get_geometry(BlockBackend *blk,
uint64_t *nb_sectors_ptr)
{
int64_t ret = blk_nb_sectors(blk);
*nb_sectors_ptr = ret < 0 ? 0 : ret;
}
BlockAIOCB *blk_aio_preadv(BlockBackend *blk, int64_t offset,
QEMUIOVector *qiov, BdrvRequestFlags flags,
BlockCompletionFunc *cb, void *opaque)
{
IO_CODE();
assert((uint64_t)qiov->size <= INT64_MAX);
return blk_aio_prwv(blk, offset, qiov->size, qiov,
blk_aio_read_entry, flags, cb, opaque);
}
BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset,
QEMUIOVector *qiov, BdrvRequestFlags flags,
BlockCompletionFunc *cb, void *opaque)
{
IO_CODE();
assert((uint64_t)qiov->size <= INT64_MAX);
return blk_aio_prwv(blk, offset, qiov->size, qiov,
blk_aio_write_entry, flags, cb, opaque);
}
void blk_aio_cancel(BlockAIOCB *acb)
{
GLOBAL_STATE_CODE();
bdrv_aio_cancel(acb);
}
void blk_aio_cancel_async(BlockAIOCB *acb)
{
IO_CODE();
bdrv_aio_cancel_async(acb);
}
/* To be called between exactly one pair of blk_inc/dec_in_flight() */
static int coroutine_fn
blk_co_do_ioctl(BlockBackend *blk, unsigned long int req, void *buf)
{
IO_CODE();
blk_wait_while_drained(blk);
GRAPH_RDLOCK_GUARD();
if (!blk_co_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_co_ioctl(blk_bs(blk), req, buf);
}
int coroutine_fn blk_co_ioctl(BlockBackend *blk, unsigned long int req,
void *buf)
{
int ret;
IO_OR_GS_CODE();
blk_inc_in_flight(blk);
ret = blk_co_do_ioctl(blk, req, buf);
blk_dec_in_flight(blk);
return ret;
}
static void coroutine_fn blk_aio_ioctl_entry(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
BlkRwCo *rwco = &acb->rwco;
rwco->ret = blk_co_do_ioctl(rwco->blk, rwco->offset, rwco->iobuf);
blk_aio_complete(acb);
}
BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
BlockCompletionFunc *cb, void *opaque)
{
IO_CODE();
return blk_aio_prwv(blk, req, 0, buf, blk_aio_ioctl_entry, 0, cb, opaque);
}
/* To be called between exactly one pair of blk_inc/dec_in_flight() */
static int coroutine_fn
blk_co_do_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes)
{
int ret;
IO_CODE();
blk_wait_while_drained(blk);
GRAPH_RDLOCK_GUARD();
ret = blk_check_byte_request(blk, offset, bytes);
if (ret < 0) {
return ret;
}
return bdrv_co_pdiscard(blk->root, offset, bytes);
}
static void coroutine_fn blk_aio_pdiscard_entry(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
BlkRwCo *rwco = &acb->rwco;
rwco->ret = blk_co_do_pdiscard(rwco->blk, rwco->offset, acb->bytes);
blk_aio_complete(acb);
}
BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk,
int64_t offset, int64_t bytes,
BlockCompletionFunc *cb, void *opaque)
{
IO_CODE();
return blk_aio_prwv(blk, offset, bytes, NULL, blk_aio_pdiscard_entry, 0,
cb, opaque);
}
int coroutine_fn blk_co_pdiscard(BlockBackend *blk, int64_t offset,
int64_t bytes)
{
int ret;
IO_OR_GS_CODE();
blk_inc_in_flight(blk);
ret = blk_co_do_pdiscard(blk, offset, bytes);
blk_dec_in_flight(blk);
return ret;
}
/* To be called between exactly one pair of blk_inc/dec_in_flight() */
static int coroutine_fn blk_co_do_flush(BlockBackend *blk)
{
IO_CODE();
blk_wait_while_drained(blk);
GRAPH_RDLOCK_GUARD();
if (!blk_co_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_co_flush(blk_bs(blk));
}
static void coroutine_fn blk_aio_flush_entry(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
BlkRwCo *rwco = &acb->rwco;
rwco->ret = blk_co_do_flush(rwco->blk);
blk_aio_complete(acb);
}
BlockAIOCB *blk_aio_flush(BlockBackend *blk,
BlockCompletionFunc *cb, void *opaque)
{
IO_CODE();
return blk_aio_prwv(blk, 0, 0, NULL, blk_aio_flush_entry, 0, cb, opaque);
}
int coroutine_fn blk_co_flush(BlockBackend *blk)
{
int ret;
IO_OR_GS_CODE();
blk_inc_in_flight(blk);
ret = blk_co_do_flush(blk);
blk_dec_in_flight(blk);
return ret;
}
static void coroutine_fn blk_aio_zone_report_entry(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
BlkRwCo *rwco = &acb->rwco;
rwco->ret = blk_co_zone_report(rwco->blk, rwco->offset,
(unsigned int*)(uintptr_t)acb->bytes,
rwco->iobuf);
blk_aio_complete(acb);
}
BlockAIOCB *blk_aio_zone_report(BlockBackend *blk, int64_t offset,
unsigned int *nr_zones,
BlockZoneDescriptor *zones,
BlockCompletionFunc *cb, void *opaque)
{
BlkAioEmAIOCB *acb;
Coroutine *co;
IO_CODE();
blk_inc_in_flight(blk);
acb = blk_aio_get(&blk_aio_em_aiocb_info, blk, cb, opaque);
acb->rwco = (BlkRwCo) {
.blk = blk,
.offset = offset,
.iobuf = zones,
.ret = NOT_DONE,
};
acb->bytes = (int64_t)(uintptr_t)nr_zones,
acb->has_returned = false;
co = qemu_coroutine_create(blk_aio_zone_report_entry, acb);
aio_co_enter(qemu_get_current_aio_context(), co);
acb->has_returned = true;
if (acb->rwco.ret != NOT_DONE) {
replay_bh_schedule_oneshot_event(qemu_get_current_aio_context(),
blk_aio_complete_bh, acb);
}
return &acb->common;
}
static void coroutine_fn blk_aio_zone_mgmt_entry(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
BlkRwCo *rwco = &acb->rwco;
rwco->ret = blk_co_zone_mgmt(rwco->blk,
(BlockZoneOp)(uintptr_t)rwco->iobuf,
rwco->offset, acb->bytes);
blk_aio_complete(acb);
}
BlockAIOCB *blk_aio_zone_mgmt(BlockBackend *blk, BlockZoneOp op,
int64_t offset, int64_t len,
BlockCompletionFunc *cb, void *opaque) {
BlkAioEmAIOCB *acb;
Coroutine *co;
IO_CODE();
blk_inc_in_flight(blk);
acb = blk_aio_get(&blk_aio_em_aiocb_info, blk, cb, opaque);
acb->rwco = (BlkRwCo) {
.blk = blk,
.offset = offset,
.iobuf = (void *)(uintptr_t)op,
.ret = NOT_DONE,
};
acb->bytes = len;
acb->has_returned = false;
co = qemu_coroutine_create(blk_aio_zone_mgmt_entry, acb);
aio_co_enter(qemu_get_current_aio_context(), co);
acb->has_returned = true;
if (acb->rwco.ret != NOT_DONE) {
replay_bh_schedule_oneshot_event(qemu_get_current_aio_context(),
blk_aio_complete_bh, acb);
}
return &acb->common;
}
static void coroutine_fn blk_aio_zone_append_entry(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
BlkRwCo *rwco = &acb->rwco;
rwco->ret = blk_co_zone_append(rwco->blk, (int64_t *)(uintptr_t)acb->bytes,
rwco->iobuf, rwco->flags);
blk_aio_complete(acb);
}
BlockAIOCB *blk_aio_zone_append(BlockBackend *blk, int64_t *offset,
QEMUIOVector *qiov, BdrvRequestFlags flags,
BlockCompletionFunc *cb, void *opaque) {
BlkAioEmAIOCB *acb;
Coroutine *co;
IO_CODE();
blk_inc_in_flight(blk);
acb = blk_aio_get(&blk_aio_em_aiocb_info, blk, cb, opaque);
acb->rwco = (BlkRwCo) {
.blk = blk,
.ret = NOT_DONE,
.flags = flags,
.iobuf = qiov,
};
acb->bytes = (int64_t)(uintptr_t)offset;
acb->has_returned = false;
co = qemu_coroutine_create(blk_aio_zone_append_entry, acb);
aio_co_enter(qemu_get_current_aio_context(), co);
acb->has_returned = true;
if (acb->rwco.ret != NOT_DONE) {
replay_bh_schedule_oneshot_event(qemu_get_current_aio_context(),
blk_aio_complete_bh, acb);
}
return &acb->common;
}
/*
* Send a zone_report command.
* offset is a byte offset from the start of the device. No alignment
* required for offset.
* nr_zones represents IN maximum and OUT actual.
*/
int coroutine_fn blk_co_zone_report(BlockBackend *blk, int64_t offset,
unsigned int *nr_zones,
BlockZoneDescriptor *zones)
{
int ret;
IO_CODE();
blk_inc_in_flight(blk); /* increase before waiting */
blk_wait_while_drained(blk);
GRAPH_RDLOCK_GUARD();
if (!blk_is_available(blk)) {
blk_dec_in_flight(blk);
return -ENOMEDIUM;
}
ret = bdrv_co_zone_report(blk_bs(blk), offset, nr_zones, zones);
blk_dec_in_flight(blk);
return ret;
}
/*
* Send a zone_management command.
* op is the zone operation;
* offset is the byte offset from the start of the zoned device;
* len is the maximum number of bytes the command should operate on. It
* should be aligned with the device zone size.
*/
int coroutine_fn blk_co_zone_mgmt(BlockBackend *blk, BlockZoneOp op,
int64_t offset, int64_t len)
{
int ret;
IO_CODE();
blk_inc_in_flight(blk);
blk_wait_while_drained(blk);
GRAPH_RDLOCK_GUARD();
ret = blk_check_byte_request(blk, offset, len);
if (ret < 0) {
blk_dec_in_flight(blk);
return ret;
}
ret = bdrv_co_zone_mgmt(blk_bs(blk), op, offset, len);
blk_dec_in_flight(blk);
return ret;
}
/*
* Send a zone_append command.
*/
int coroutine_fn blk_co_zone_append(BlockBackend *blk, int64_t *offset,
QEMUIOVector *qiov, BdrvRequestFlags flags)
{
int ret;
IO_CODE();
blk_inc_in_flight(blk);
blk_wait_while_drained(blk);
GRAPH_RDLOCK_GUARD();
if (!blk_is_available(blk)) {
blk_dec_in_flight(blk);
return -ENOMEDIUM;
}
ret = bdrv_co_zone_append(blk_bs(blk), offset, qiov, flags);
blk_dec_in_flight(blk);
return ret;
}
void blk_drain(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (bs) {
bdrv_ref(bs);
bdrv_drained_begin(bs);
}
/* We may have -ENOMEDIUM completions in flight */
AIO_WAIT_WHILE(blk_get_aio_context(blk),
qatomic_read(&blk->in_flight) > 0);
if (bs) {
bdrv_drained_end(bs);
bdrv_unref(bs);
}
}
void blk_drain_all(void)
{
BlockBackend *blk = NULL;
GLOBAL_STATE_CODE();
bdrv_drain_all_begin();
while ((blk = blk_all_next(blk)) != NULL) {
/* We may have -ENOMEDIUM completions in flight */
AIO_WAIT_WHILE_UNLOCKED(NULL, qatomic_read(&blk->in_flight) > 0);
}
bdrv_drain_all_end();
}
void blk_set_on_error(BlockBackend *blk, BlockdevOnError on_read_error,
BlockdevOnError on_write_error)
{
GLOBAL_STATE_CODE();
blk->on_read_error = on_read_error;
blk->on_write_error = on_write_error;
}
BlockdevOnError blk_get_on_error(BlockBackend *blk, bool is_read)
{
IO_CODE();
return is_read ? blk->on_read_error : blk->on_write_error;
}
BlockErrorAction blk_get_error_action(BlockBackend *blk, bool is_read,
int error)
{
BlockdevOnError on_err = blk_get_on_error(blk, is_read);
IO_CODE();
switch (on_err) {
case BLOCKDEV_ON_ERROR_ENOSPC:
return (error == ENOSPC) ?
BLOCK_ERROR_ACTION_STOP : BLOCK_ERROR_ACTION_REPORT;
case BLOCKDEV_ON_ERROR_STOP:
return BLOCK_ERROR_ACTION_STOP;
case BLOCKDEV_ON_ERROR_REPORT:
return BLOCK_ERROR_ACTION_REPORT;
case BLOCKDEV_ON_ERROR_IGNORE:
return BLOCK_ERROR_ACTION_IGNORE;
case BLOCKDEV_ON_ERROR_AUTO:
default:
abort();
}
}
static void send_qmp_error_event(BlockBackend *blk,
BlockErrorAction action,
bool is_read, int error)
{
IoOperationType optype;
BlockDriverState *bs = blk_bs(blk);
optype = is_read ? IO_OPERATION_TYPE_READ : IO_OPERATION_TYPE_WRITE;
qapi_event_send_block_io_error(blk_name(blk),
bs ? bdrv_get_node_name(bs) : NULL, optype,
action, blk_iostatus_is_enabled(blk),
error == ENOSPC, strerror(error));
}
/* This is done by device models because, while the block layer knows
* about the error, it does not know whether an operation comes from
* the device or the block layer (from a job, for example).
*/
void blk_error_action(BlockBackend *blk, BlockErrorAction action,
bool is_read, int error)
{
assert(error >= 0);
IO_CODE();
if (action == BLOCK_ERROR_ACTION_STOP) {
/* First set the iostatus, so that "info block" returns an iostatus
* that matches the events raised so far (an additional error iostatus
* is fine, but not a lost one).
*/
blk_iostatus_set_err(blk, error);
/* Then raise the request to stop the VM and the event.
* qemu_system_vmstop_request_prepare has two effects. First,
* it ensures that the STOP event always comes after the
* BLOCK_IO_ERROR event. Second, it ensures that even if management
* can observe the STOP event and do a "cont" before the STOP
* event is issued, the VM will not stop. In this case, vm_start()
* also ensures that the STOP/RESUME pair of events is emitted.
*/
qemu_system_vmstop_request_prepare();
send_qmp_error_event(blk, action, is_read, error);
qemu_system_vmstop_request(RUN_STATE_IO_ERROR);
} else {
send_qmp_error_event(blk, action, is_read, error);
}
}
/*
* Returns true if the BlockBackend can support taking write permissions
* (because its root node is not read-only).
*/
bool blk_supports_write_perm(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (bs) {
return !bdrv_is_read_only(bs);
} else {
return blk->root_state.open_flags & BDRV_O_RDWR;
}
}
/*
* Returns true if the BlockBackend can be written to in its current
* configuration (i.e. if write permission have been requested)
*/
bool blk_is_writable(BlockBackend *blk)
{
IO_CODE();
return blk->perm & BLK_PERM_WRITE;
}
bool blk_is_sg(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (!bs) {
return false;
}
return bdrv_is_sg(bs);
}
bool blk_enable_write_cache(BlockBackend *blk)
{
IO_CODE();
return blk->enable_write_cache;
}
void blk_set_enable_write_cache(BlockBackend *blk, bool wce)
{
IO_CODE();
blk->enable_write_cache = wce;
}
void blk_activate(BlockBackend *blk, Error **errp)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (!bs) {
error_setg(errp, "Device '%s' has no medium", blk->name);
return;
}
/*
* Migration code can call this function in coroutine context, so leave
* coroutine context if necessary.
*/
if (qemu_in_coroutine()) {
bdrv_co_activate(bs, errp);
} else {
GRAPH_RDLOCK_GUARD_MAINLOOP();
bdrv_activate(bs, errp);
}
}
bool coroutine_fn blk_co_is_inserted(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
IO_CODE();
assert_bdrv_graph_readable();
return bs && bdrv_co_is_inserted(bs);
}
bool coroutine_fn blk_co_is_available(BlockBackend *blk)
{
IO_CODE();
return blk_co_is_inserted(blk) && !blk_dev_is_tray_open(blk);
}
void coroutine_fn blk_co_lock_medium(BlockBackend *blk, bool locked)
{
BlockDriverState *bs = blk_bs(blk);
IO_CODE();
GRAPH_RDLOCK_GUARD();
if (bs) {
bdrv_co_lock_medium(bs, locked);
}
}
void coroutine_fn blk_co_eject(BlockBackend *blk, bool eject_flag)
{
BlockDriverState *bs = blk_bs(blk);
char *id;
IO_CODE();
GRAPH_RDLOCK_GUARD();
if (bs) {
bdrv_co_eject(bs, eject_flag);
}
/* Whether or not we ejected on the backend,
* the frontend experienced a tray event. */
id = blk_get_attached_dev_id(blk);
qapi_event_send_device_tray_moved(blk_name(blk), id,
eject_flag);
g_free(id);
}
int blk_get_flags(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (bs) {
return bdrv_get_flags(bs);
} else {
return blk->root_state.open_flags;
}
}
/* Returns the minimum request alignment, in bytes; guaranteed nonzero */
uint32_t blk_get_request_alignment(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
IO_CODE();
return bs ? bs->bl.request_alignment : BDRV_SECTOR_SIZE;
}
/* Returns the maximum hardware transfer length, in bytes; guaranteed nonzero */
uint64_t blk_get_max_hw_transfer(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
uint64_t max = INT_MAX;
IO_CODE();
if (bs) {
max = MIN_NON_ZERO(max, bs->bl.max_hw_transfer);
max = MIN_NON_ZERO(max, bs->bl.max_transfer);
}
return ROUND_DOWN(max, blk_get_request_alignment(blk));
}
/* Returns the maximum transfer length, in bytes; guaranteed nonzero */
uint32_t blk_get_max_transfer(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
uint32_t max = INT_MAX;
IO_CODE();
if (bs) {
max = MIN_NON_ZERO(max, bs->bl.max_transfer);
}
return ROUND_DOWN(max, blk_get_request_alignment(blk));
}
int blk_get_max_hw_iov(BlockBackend *blk)
{
IO_CODE();
return MIN_NON_ZERO(blk->root->bs->bl.max_hw_iov,
blk->root->bs->bl.max_iov);
}
int blk_get_max_iov(BlockBackend *blk)
{
IO_CODE();
return blk->root->bs->bl.max_iov;
}
void *blk_try_blockalign(BlockBackend *blk, size_t size)
{
IO_CODE();
return qemu_try_blockalign(blk ? blk_bs(blk) : NULL, size);
}
void *blk_blockalign(BlockBackend *blk, size_t size)
{
IO_CODE();
return qemu_blockalign(blk ? blk_bs(blk) : NULL, size);
}
bool blk_op_is_blocked(BlockBackend *blk, BlockOpType op, Error **errp)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
GRAPH_RDLOCK_GUARD_MAINLOOP();
if (!bs) {
return false;
}
return bdrv_op_is_blocked(bs, op, errp);
}
void blk_op_unblock(BlockBackend *blk, BlockOpType op, Error *reason)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (bs) {
bdrv_op_unblock(bs, op, reason);
}
}
void blk_op_block_all(BlockBackend *blk, Error *reason)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (bs) {
bdrv_op_block_all(bs, reason);
}
}
void blk_op_unblock_all(BlockBackend *blk, Error *reason)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (bs) {
bdrv_op_unblock_all(bs, reason);
}
}
/**
* Return BB's current AioContext. Note that this context may change
* concurrently at any time, with one exception: If the BB has a root node
* attached, its context will only change through bdrv_try_change_aio_context(),
* which creates a drained section. Therefore, incrementing such a BB's
* in-flight counter will prevent its context from changing.
*/
AioContext *blk_get_aio_context(BlockBackend *blk)
{
IO_CODE();
if (!blk) {
return qemu_get_aio_context();
}
return qatomic_read(&blk->ctx);
}
int blk_set_aio_context(BlockBackend *blk, AioContext *new_context,
Error **errp)
{
bool old_allow_change;
BlockDriverState *bs = blk_bs(blk);
int ret;
GLOBAL_STATE_CODE();
if (!bs) {
qatomic_set(&blk->ctx, new_context);
return 0;
}
bdrv_ref(bs);
old_allow_change = blk->allow_aio_context_change;
blk->allow_aio_context_change = true;
ret = bdrv_try_change_aio_context(bs, new_context, NULL, errp);
blk->allow_aio_context_change = old_allow_change;
bdrv_unref(bs);
return ret;
}
typedef struct BdrvStateBlkRootContext {
AioContext *new_ctx;
BlockBackend *blk;
} BdrvStateBlkRootContext;
static void blk_root_set_aio_ctx_commit(void *opaque)
{
BdrvStateBlkRootContext *s = opaque;
BlockBackend *blk = s->blk;
AioContext *new_context = s->new_ctx;
ThrottleGroupMember *tgm = &blk->public.throttle_group_member;
qatomic_set(&blk->ctx, new_context);
if (tgm->throttle_state) {
throttle_group_detach_aio_context(tgm);
throttle_group_attach_aio_context(tgm, new_context);
}
}
static TransactionActionDrv set_blk_root_context = {
.commit = blk_root_set_aio_ctx_commit,
.clean = g_free,
};
static bool blk_root_change_aio_ctx(BdrvChild *child, AioContext *ctx,
GHashTable *visited, Transaction *tran,
Error **errp)
{
BlockBackend *blk = child->opaque;
BdrvStateBlkRootContext *s;
if (!blk->allow_aio_context_change) {
/*
* Manually created BlockBackends (those with a name) that are not
* attached to anything can change their AioContext without updating
* their user; return an error for others.
*/
if (!blk->name || blk->dev) {
/* TODO Add BB name/QOM path */
error_setg(errp, "Cannot change iothread of active block backend");
return false;
}
}
s = g_new(BdrvStateBlkRootContext, 1);
*s = (BdrvStateBlkRootContext) {
.new_ctx = ctx,
.blk = blk,
};
tran_add(tran, &set_blk_root_context, s);
return true;
}
void blk_add_aio_context_notifier(BlockBackend *blk,
void (*attached_aio_context)(AioContext *new_context, void *opaque),
void (*detach_aio_context)(void *opaque), void *opaque)
{
BlockBackendAioNotifier *notifier;
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
notifier = g_new(BlockBackendAioNotifier, 1);
notifier->attached_aio_context = attached_aio_context;
notifier->detach_aio_context = detach_aio_context;
notifier->opaque = opaque;
QLIST_INSERT_HEAD(&blk->aio_notifiers, notifier, list);
if (bs) {
bdrv_add_aio_context_notifier(bs, attached_aio_context,
detach_aio_context, opaque);
}
}
void blk_remove_aio_context_notifier(BlockBackend *blk,
void (*attached_aio_context)(AioContext *,
void *),
void (*detach_aio_context)(void *),
void *opaque)
{
BlockBackendAioNotifier *notifier;
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (bs) {
bdrv_remove_aio_context_notifier(bs, attached_aio_context,
detach_aio_context, opaque);
}
QLIST_FOREACH(notifier, &blk->aio_notifiers, list) {
if (notifier->attached_aio_context == attached_aio_context &&
notifier->detach_aio_context == detach_aio_context &&
notifier->opaque == opaque) {
QLIST_REMOVE(notifier, list);
g_free(notifier);
return;
}
}
abort();
}
void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify)
{
GLOBAL_STATE_CODE();
notifier_list_add(&blk->remove_bs_notifiers, notify);
}
void blk_add_insert_bs_notifier(BlockBackend *blk, Notifier *notify)
{
GLOBAL_STATE_CODE();
notifier_list_add(&blk->insert_bs_notifiers, notify);
}
BlockAcctStats *blk_get_stats(BlockBackend *blk)
{
IO_CODE();
return &blk->stats;
}
void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk,
BlockCompletionFunc *cb, void *opaque)
{
IO_CODE();
return qemu_aio_get(aiocb_info, blk_bs(blk), cb, opaque);
}
int coroutine_fn blk_co_pwrite_zeroes(BlockBackend *blk, int64_t offset,
int64_t bytes, BdrvRequestFlags flags)
{
IO_OR_GS_CODE();
return blk_co_pwritev(blk, offset, bytes, NULL,
flags | BDRV_REQ_ZERO_WRITE);
}
int coroutine_fn blk_co_pwrite_compressed(BlockBackend *blk, int64_t offset,
int64_t bytes, const void *buf)
{
QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
IO_OR_GS_CODE();
return blk_co_pwritev_part(blk, offset, bytes, &qiov, 0,
BDRV_REQ_WRITE_COMPRESSED);
}
int coroutine_fn blk_co_truncate(BlockBackend *blk, int64_t offset, bool exact,
PreallocMode prealloc, BdrvRequestFlags flags,
Error **errp)
{
IO_OR_GS_CODE();
GRAPH_RDLOCK_GUARD();
if (!blk_co_is_available(blk)) {
error_setg(errp, "No medium inserted");
return -ENOMEDIUM;
}
return bdrv_co_truncate(blk->root, offset, exact, prealloc, flags, errp);
}
int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf,
int64_t pos, int size)
{
int ret;
GLOBAL_STATE_CODE();
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
ret = bdrv_save_vmstate(blk_bs(blk), buf, pos, size);
if (ret < 0) {
return ret;
}
if (ret == size && !blk->enable_write_cache) {
ret = bdrv_flush(blk_bs(blk));
}
return ret < 0 ? ret : size;
}
int blk_load_vmstate(BlockBackend *blk, uint8_t *buf, int64_t pos, int size)
{
GLOBAL_STATE_CODE();
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_load_vmstate(blk_bs(blk), buf, pos, size);
}
int blk_probe_blocksizes(BlockBackend *blk, BlockSizes *bsz)
{
GLOBAL_STATE_CODE();
GRAPH_RDLOCK_GUARD_MAINLOOP();
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_probe_blocksizes(blk_bs(blk), bsz);
}
int blk_probe_geometry(BlockBackend *blk, HDGeometry *geo)
{
GLOBAL_STATE_CODE();
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_probe_geometry(blk_bs(blk), geo);
}
/*
* Updates the BlockBackendRootState object with data from the currently
* attached BlockDriverState.
*/
void blk_update_root_state(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
assert(blk->root);
blk->root_state.open_flags = blk->root->bs->open_flags;
blk->root_state.detect_zeroes = blk->root->bs->detect_zeroes;
}
/*
* Returns the detect-zeroes setting to be used for bdrv_open() of a
* BlockDriverState which is supposed to inherit the root state.
*/
bool blk_get_detect_zeroes_from_root_state(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return blk->root_state.detect_zeroes;
}
/*
* Returns the flags to be used for bdrv_open() of a BlockDriverState which is
* supposed to inherit the root state.
*/
int blk_get_open_flags_from_root_state(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return blk->root_state.open_flags;
}
BlockBackendRootState *blk_get_root_state(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return &blk->root_state;
}
int blk_commit_all(void)
{
BlockBackend *blk = NULL;
GLOBAL_STATE_CODE();
GRAPH_RDLOCK_GUARD_MAINLOOP();
while ((blk = blk_all_next(blk)) != NULL) {
BlockDriverState *unfiltered_bs = bdrv_skip_filters(blk_bs(blk));
if (blk_is_inserted(blk) && bdrv_cow_child(unfiltered_bs)) {
int ret;
ret = bdrv_commit(unfiltered_bs);
if (ret < 0) {
return ret;
}
}
}
return 0;
}
/* throttling disk I/O limits */
void blk_set_io_limits(BlockBackend *blk, ThrottleConfig *cfg)
{
GLOBAL_STATE_CODE();
throttle_group_config(&blk->public.throttle_group_member, cfg);
}
void blk_io_limits_disable(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
ThrottleGroupMember *tgm = &blk->public.throttle_group_member;
assert(tgm->throttle_state);
GLOBAL_STATE_CODE();
if (bs) {
bdrv_ref(bs);
bdrv_drained_begin(bs);
}
throttle_group_unregister_tgm(tgm);
if (bs) {
bdrv_drained_end(bs);
bdrv_unref(bs);
}
}
/* should be called before blk_set_io_limits if a limit is set */
void blk_io_limits_enable(BlockBackend *blk, const char *group)
{
assert(!blk->public.throttle_group_member.throttle_state);
GLOBAL_STATE_CODE();
throttle_group_register_tgm(&blk->public.throttle_group_member,
group, blk_get_aio_context(blk));
}
void blk_io_limits_update_group(BlockBackend *blk, const char *group)
{
GLOBAL_STATE_CODE();
/* this BB is not part of any group */
if (!blk->public.throttle_group_member.throttle_state) {
return;
}
/* this BB is a part of the same group than the one we want */
if (!g_strcmp0(throttle_group_get_name(&blk->public.throttle_group_member),
group)) {
return;
}
/* need to change the group this bs belong to */
blk_io_limits_disable(blk);
blk_io_limits_enable(blk, group);
}
static void blk_root_drained_begin(BdrvChild *child)
{
BlockBackend *blk = child->opaque;
ThrottleGroupMember *tgm = &blk->public.throttle_group_member;
if (qatomic_fetch_inc(&blk->quiesce_counter) == 0) {
if (blk->dev_ops && blk->dev_ops->drained_begin) {
blk->dev_ops->drained_begin(blk->dev_opaque);
}
}
/* Note that blk->root may not be accessible here yet if we are just
* attaching to a BlockDriverState that is drained. Use child instead. */
if (qatomic_fetch_inc(&tgm->io_limits_disabled) == 0) {
throttle_group_restart_tgm(tgm);
}
}
static bool blk_root_drained_poll(BdrvChild *child)
{
BlockBackend *blk = child->opaque;
bool busy = false;
assert(qatomic_read(&blk->quiesce_counter));
if (blk->dev_ops && blk->dev_ops->drained_poll) {
busy = blk->dev_ops->drained_poll(blk->dev_opaque);
}
return busy || !!blk->in_flight;
}
static void blk_root_drained_end(BdrvChild *child)
{
BlockBackend *blk = child->opaque;
assert(qatomic_read(&blk->quiesce_counter));
assert(blk->public.throttle_group_member.io_limits_disabled);
qatomic_dec(&blk->public.throttle_group_member.io_limits_disabled);
if (qatomic_fetch_dec(&blk->quiesce_counter) == 1) {
if (blk->dev_ops && blk->dev_ops->drained_end) {
blk->dev_ops->drained_end(blk->dev_opaque);
}
qemu_mutex_lock(&blk->queued_requests_lock);
while (qemu_co_enter_next(&blk->queued_requests,
&blk->queued_requests_lock)) {
/* Resume all queued requests */
}
qemu_mutex_unlock(&blk->queued_requests_lock);
}
}
bool blk_register_buf(BlockBackend *blk, void *host, size_t size, Error **errp)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (bs) {
return bdrv_register_buf(bs, host, size, errp);
}
return true;
}
void blk_unregister_buf(BlockBackend *blk, void *host, size_t size)
{
BlockDriverState *bs = blk_bs(blk);
GLOBAL_STATE_CODE();
if (bs) {
bdrv_unregister_buf(bs, host, size);
}
}
int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,
BlockBackend *blk_out, int64_t off_out,
int64_t bytes, BdrvRequestFlags read_flags,
BdrvRequestFlags write_flags)
{
int r;
IO_CODE();
GRAPH_RDLOCK_GUARD();
r = blk_check_byte_request(blk_in, off_in, bytes);
if (r) {
return r;
}
r = blk_check_byte_request(blk_out, off_out, bytes);
if (r) {
return r;
}
return bdrv_co_copy_range(blk_in->root, off_in,
blk_out->root, off_out,
bytes, read_flags, write_flags);
}
const BdrvChild *blk_root(BlockBackend *blk)
{
GLOBAL_STATE_CODE();
return blk->root;
}
int blk_make_empty(BlockBackend *blk, Error **errp)
{
GLOBAL_STATE_CODE();
GRAPH_RDLOCK_GUARD_MAINLOOP();
if (!blk_is_available(blk)) {
error_setg(errp, "No medium inserted");
return -ENOMEDIUM;
}
return bdrv_make_empty(blk->root, errp);
}
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