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qemu/block/block-backend.c
Kevin Wolf 61de4c6808 block: Remove BDRV_O_CACHE_WB 
The previous patches have successively made blk->enable_write_cache the
true source for the information whether a writethrough mode must be
implemented. The corresponding BDRV_O_CACHE_WB is only useless baggage
we're carrying around, so now's the time to remove it.

At the same time, we remove the 'cache.writeback' option parsing on the
BDS level as the only effect was setting the BDRV_O_CACHE_WB flag.

This change requires test cases that explicitly enabled the option to
drop it. Other than that and the change of the error message when
writethrough is enabled on the BDS level (from "Can't set writethrough
mode" to "doesn't support the option"), there should be no change in
behaviour.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2016-03-30 12:16:03 +02:00

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/*
* QEMU Block backends
*
* Copyright (C) 2014 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/throttle-groups.h"
#include "sysemu/blockdev.h"
#include "sysemu/sysemu.h"
#include "qapi-event.h"
#include "qemu/id.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 */
static AioContext *blk_aiocb_get_aio_context(BlockAIOCB *acb);
struct BlockBackend {
char *name;
int refcnt;
BdrvChild *root;
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 */
void *dev; /* attached device model, if any */
/* TODO change to DeviceState when all users are qdevified */
const BlockDevOps *dev_ops;
void *dev_opaque;
/* the block size for which the guest device expects atomicity */
int guest_block_size;
/* 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;
bool allow_write_beyond_eof;
NotifierList remove_bs_notifiers, insert_bs_notifiers;
};
typedef struct BlockBackendAIOCB {
BlockAIOCB common;
QEMUBH *bh;
BlockBackend *blk;
int ret;
} BlockBackendAIOCB;
static const AIOCBInfo block_backend_aiocb_info = {
.get_aio_context = blk_aiocb_get_aio_context,
.aiocb_size = sizeof(BlockBackendAIOCB),
};
static void drive_info_del(DriveInfo *dinfo);
/* All BlockBackends */
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() */
static QTAILQ_HEAD(, BlockBackend) monitor_block_backends =
QTAILQ_HEAD_INITIALIZER(monitor_block_backends);
static void blk_root_inherit_options(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 const BdrvChildRole child_root = {
.inherit_options = blk_root_inherit_options,
};
/*
* Create a new BlockBackend with a reference count of one.
* Store an error through @errp on failure, unless it's null.
* Return the new BlockBackend on success, null on failure.
*/
BlockBackend *blk_new(Error **errp)
{
BlockBackend *blk;
blk = g_new0(BlockBackend, 1);
blk->refcnt = 1;
notifier_list_init(&blk->remove_bs_notifiers);
notifier_list_init(&blk->insert_bs_notifiers);
QTAILQ_INSERT_TAIL(&block_backends, blk, link);
return blk;
}
/*
* Create a new BlockBackend with a new BlockDriverState attached.
* Otherwise just like blk_new(), which see.
*/
BlockBackend *blk_new_with_bs(Error **errp)
{
BlockBackend *blk;
BlockDriverState *bs;
blk = blk_new(errp);
if (!blk) {
return NULL;
}
bs = bdrv_new_root();
blk->root = bdrv_root_attach_child(bs, "root", &child_root);
bs->blk = blk;
return blk;
}
/*
* Calls blk_new_with_bs() and then calls bdrv_open() on the BlockDriverState.
*
* 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;
int ret;
blk = blk_new_with_bs(errp);
if (!blk) {
QDECREF(options);
return NULL;
}
ret = bdrv_open(&blk->root->bs, filename, reference, options, flags, errp);
if (ret < 0) {
blk_unref(blk);
return NULL;
}
blk_set_enable_write_cache(blk, true);
return blk;
}
static void blk_delete(BlockBackend *blk)
{
assert(!blk->refcnt);
assert(!blk->name);
assert(!blk->dev);
if (blk->root) {
blk_remove_bs(blk);
}
assert(QLIST_EMPTY(&blk->remove_bs_notifiers.notifiers));
assert(QLIST_EMPTY(&blk->insert_bs_notifiers.notifiers));
if (blk->root_state.throttle_state) {
g_free(blk->root_state.throttle_group);
throttle_group_unref(blk->root_state.throttle_state);
}
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->serial);
g_free(dinfo);
}
int blk_get_refcnt(BlockBackend *blk)
{
return blk ? blk->refcnt : 0;
}
/*
* Increment @blk's reference count.
* @blk must not be null.
*/
void blk_ref(BlockBackend *blk)
{
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)
{
if (blk) {
assert(blk->refcnt > 0);
if (!--blk->refcnt) {
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).
*/
static BlockBackend *blk_all_next(BlockBackend *blk)
{
return blk ? QTAILQ_NEXT(blk, link)
: QTAILQ_FIRST(&block_backends);
}
void blk_remove_all_bs(void)
{
BlockBackend *blk = NULL;
while ((blk = blk_all_next(blk)) != NULL) {
AioContext *ctx = blk_get_aio_context(blk);
aio_context_acquire(ctx);
if (blk->root) {
blk_remove_bs(blk);
}
aio_context_release(ctx);
}
}
/*
* 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)
{
return blk ? QTAILQ_NEXT(blk, monitor_link)
: QTAILQ_FIRST(&monitor_block_backends);
}
/*
* Iterates over all BlockDriverStates which are attached to a BlockBackend.
* This function is for use by bdrv_next().
*
* @bs must be NULL or a BDS that is attached to a BB.
*/
BlockDriverState *blk_next_root_bs(BlockDriverState *bs)
{
BlockBackend *blk;
if (bs) {
assert(bs->blk);
blk = bs->blk;
} else {
blk = NULL;
}
do {
blk = blk_all_next(blk);
} while (blk && !blk->root);
return blk ? blk->root->bs : NULL;
}
/*
* 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]);
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)
{
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(BlockBackend *blk)
{
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;
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)
{
return blk->root ? blk->root->bs : NULL;
}
/*
* Return @blk's DriveInfo if any, else null.
*/
DriveInfo *blk_legacy_dinfo(BlockBackend *blk)
{
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);
return blk->legacy_dinfo = dinfo;
}
/*
* Return the BlockBackend with DriveInfo @dinfo.
* It must exist.
*/
BlockBackend *blk_by_legacy_dinfo(DriveInfo *dinfo)
{
BlockBackend *blk = NULL;
while ((blk = blk_next(blk)) != NULL) {
if (blk->legacy_dinfo == dinfo) {
return blk;
}
}
abort();
}
/*
* Disassociates the currently associated BlockDriverState from @blk.
*/
void blk_remove_bs(BlockBackend *blk)
{
assert(blk->root->bs->blk == blk);
notifier_list_notify(&blk->remove_bs_notifiers, blk);
blk_update_root_state(blk);
blk->root->bs->blk = NULL;
bdrv_root_unref_child(blk->root);
blk->root = NULL;
}
/*
* Associates a new BlockDriverState with @blk.
*/
void blk_insert_bs(BlockBackend *blk, BlockDriverState *bs)
{
assert(!blk->root && !bs->blk);
bdrv_ref(bs);
blk->root = bdrv_root_attach_child(bs, "root", &child_root);
bs->blk = blk;
notifier_list_notify(&blk->insert_bs_notifiers, blk);
}
/*
* Attach device model @dev to @blk.
* Return 0 on success, -EBUSY when a device model is attached already.
*/
int blk_attach_dev(BlockBackend *blk, void *dev)
/* TODO change to DeviceState *dev when all users are qdevified */
{
if (blk->dev) {
return -EBUSY;
}
blk_ref(blk);
blk->dev = dev;
blk_iostatus_reset(blk);
return 0;
}
/*
* Attach device model @dev to @blk.
* @blk must not have a device model attached already.
* TODO qdevified devices don't use this, remove when devices are qdevified
*/
void blk_attach_dev_nofail(BlockBackend *blk, void *dev)
{
if (blk_attach_dev(blk, dev) < 0) {
abort();
}
}
/*
* Detach device model @dev from @blk.
* @dev must be currently attached to @blk.
*/
void blk_detach_dev(BlockBackend *blk, void *dev)
/* TODO change to DeviceState *dev when all users are qdevified */
{
assert(blk->dev == dev);
blk->dev = NULL;
blk->dev_ops = NULL;
blk->dev_opaque = NULL;
blk->guest_block_size = 512;
blk_unref(blk);
}
/*
* Return the device model attached to @blk if any, else null.
*/
void *blk_get_attached_dev(BlockBackend *blk)
/* TODO change to return DeviceState * when all users are qdevified */
{
return blk->dev;
}
/*
* 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)
{
blk->dev_ops = ops;
blk->dev_opaque = opaque;
}
/*
* Notify @blk's attached device model of media change.
* If @load is true, notify of media load.
* Else, notify of media eject.
* Also send DEVICE_TRAY_MOVED events as appropriate.
*/
void blk_dev_change_media_cb(BlockBackend *blk, bool load)
{
if (blk->dev_ops && blk->dev_ops->change_media_cb) {
bool tray_was_open, tray_is_open;
tray_was_open = blk_dev_is_tray_open(blk);
blk->dev_ops->change_media_cb(blk->dev_opaque, load);
tray_is_open = blk_dev_is_tray_open(blk);
if (tray_was_open != tray_is_open) {
qapi_event_send_device_tray_moved(blk_name(blk), tray_is_open,
&error_abort);
}
}
}
/*
* Does @blk's attached device model have removable media?
* %true if no device model is attached.
*/
bool blk_dev_has_removable_media(BlockBackend *blk)
{
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)
{
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)
{
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)
{
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)
{
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.
*/
void blk_dev_resize_cb(BlockBackend *blk)
{
if (blk->dev_ops && blk->dev_ops->resize_cb) {
blk->dev_ops->resize_cb(blk->dev_opaque);
}
}
void blk_iostatus_enable(BlockBackend *blk)
{
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)
{
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)
{
return blk->iostatus;
}
void blk_iostatus_disable(BlockBackend *blk)
{
blk->iostatus_enabled = false;
}
void blk_iostatus_reset(BlockBackend *blk)
{
if (blk_iostatus_is_enabled(blk)) {
BlockDriverState *bs = blk_bs(blk);
blk->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
if (bs && bs->job) {
block_job_iostatus_reset(bs->job);
}
}
}
void blk_iostatus_set_err(BlockBackend *blk, int error)
{
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)
{
blk->allow_write_beyond_eof = allow;
}
static int blk_check_byte_request(BlockBackend *blk, int64_t offset,
size_t size)
{
int64_t len;
if (size > INT_MAX) {
return -EIO;
}
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
if (offset < 0) {
return -EIO;
}
if (!blk->allow_write_beyond_eof) {
len = blk_getlength(blk);
if (len < 0) {
return len;
}
if (offset > len || len - offset < size) {
return -EIO;
}
}
return 0;
}
static int blk_check_request(BlockBackend *blk, int64_t sector_num,
int nb_sectors)
{
if (sector_num < 0 || sector_num > INT64_MAX / BDRV_SECTOR_SIZE) {
return -EIO;
}
if (nb_sectors < 0 || nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
return -EIO;
}
return blk_check_byte_request(blk, sector_num * BDRV_SECTOR_SIZE,
nb_sectors * BDRV_SECTOR_SIZE);
}
static int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags)
{
int ret = blk_check_byte_request(blk, offset, bytes);
if (ret < 0) {
return ret;
}
return bdrv_co_do_preadv(blk_bs(blk), offset, bytes, qiov, flags);
}
static int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags)
{
int ret;
ret = blk_check_byte_request(blk, offset, bytes);
if (ret < 0) {
return ret;
}
if (!blk->enable_write_cache) {
flags |= BDRV_REQ_FUA;
}
return bdrv_co_do_pwritev(blk_bs(blk), offset, bytes, qiov, flags);
}
typedef struct BlkRwCo {
BlockBackend *blk;
int64_t offset;
QEMUIOVector *qiov;
int ret;
BdrvRequestFlags flags;
} BlkRwCo;
static void blk_read_entry(void *opaque)
{
BlkRwCo *rwco = opaque;
rwco->ret = blk_co_preadv(rwco->blk, rwco->offset, rwco->qiov->size,
rwco->qiov, rwco->flags);
}
static void blk_write_entry(void *opaque)
{
BlkRwCo *rwco = opaque;
rwco->ret = blk_co_pwritev(rwco->blk, rwco->offset, rwco->qiov->size,
rwco->qiov, rwco->flags);
}
static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf,
int64_t bytes, CoroutineEntry co_entry,
BdrvRequestFlags flags)
{
AioContext *aio_context;
QEMUIOVector qiov;
struct iovec iov;
Coroutine *co;
BlkRwCo rwco;
iov = (struct iovec) {
.iov_base = buf,
.iov_len = bytes,
};
qemu_iovec_init_external(&qiov, &iov, 1);
rwco = (BlkRwCo) {
.blk = blk,
.offset = offset,
.qiov = &qiov,
.flags = flags,
.ret = NOT_DONE,
};
co = qemu_coroutine_create(co_entry);
qemu_coroutine_enter(co, &rwco);
aio_context = blk_get_aio_context(blk);
while (rwco.ret == NOT_DONE) {
aio_poll(aio_context, true);
}
return rwco.ret;
}
static int blk_rw(BlockBackend *blk, int64_t sector_num, uint8_t *buf,
int nb_sectors, CoroutineEntry co_entry,
BdrvRequestFlags flags)
{
if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return -EINVAL;
}
return blk_prw(blk, sector_num << BDRV_SECTOR_BITS, buf,
nb_sectors << BDRV_SECTOR_BITS, co_entry, flags);
}
int blk_read(BlockBackend *blk, int64_t sector_num, uint8_t *buf,
int nb_sectors)
{
return blk_rw(blk, sector_num, buf, nb_sectors, blk_read_entry, 0);
}
int blk_read_unthrottled(BlockBackend *blk, int64_t sector_num, uint8_t *buf,
int nb_sectors)
{
BlockDriverState *bs = blk_bs(blk);
bool enabled;
int ret;
ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return ret;
}
enabled = bs->io_limits_enabled;
bs->io_limits_enabled = false;
ret = blk_read(blk, sector_num, buf, nb_sectors);
bs->io_limits_enabled = enabled;
return ret;
}
int blk_write(BlockBackend *blk, int64_t sector_num, const uint8_t *buf,
int nb_sectors)
{
return blk_rw(blk, sector_num, (uint8_t*) buf, nb_sectors,
blk_write_entry, 0);
}
int blk_write_zeroes(BlockBackend *blk, int64_t sector_num,
int nb_sectors, BdrvRequestFlags flags)
{
return blk_rw(blk, sector_num, NULL, nb_sectors, blk_write_entry,
BDRV_REQ_ZERO_WRITE);
}
static void error_callback_bh(void *opaque)
{
struct BlockBackendAIOCB *acb = opaque;
qemu_bh_delete(acb->bh);
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;
QEMUBH *bh;
acb = blk_aio_get(&block_backend_aiocb_info, blk, cb, opaque);
acb->blk = blk;
acb->ret = ret;
bh = aio_bh_new(blk_get_aio_context(blk), error_callback_bh, acb);
acb->bh = bh;
qemu_bh_schedule(bh);
return &acb->common;
}
typedef struct BlkAioEmAIOCB {
BlockAIOCB common;
BlkRwCo rwco;
bool has_returned;
QEMUBH* bh;
} BlkAioEmAIOCB;
static const AIOCBInfo blk_aio_em_aiocb_info = {
.aiocb_size = sizeof(BlkAioEmAIOCB),
};
static void blk_aio_complete(BlkAioEmAIOCB *acb)
{
if (acb->bh) {
assert(acb->has_returned);
qemu_bh_delete(acb->bh);
}
if (acb->has_returned) {
acb->common.cb(acb->common.opaque, acb->rwco.ret);
qemu_aio_unref(acb);
}
}
static void blk_aio_complete_bh(void *opaque)
{
blk_aio_complete(opaque);
}
static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset,
QEMUIOVector *qiov, CoroutineEntry co_entry,
BdrvRequestFlags flags,
BlockCompletionFunc *cb, void *opaque)
{
BlkAioEmAIOCB *acb;
Coroutine *co;
acb = blk_aio_get(&blk_aio_em_aiocb_info, blk, cb, opaque);
acb->rwco = (BlkRwCo) {
.blk = blk,
.offset = offset,
.qiov = qiov,
.flags = flags,
.ret = NOT_DONE,
};
acb->bh = NULL;
acb->has_returned = false;
co = qemu_coroutine_create(co_entry);
qemu_coroutine_enter(co, acb);
acb->has_returned = true;
if (acb->rwco.ret != NOT_DONE) {
acb->bh = aio_bh_new(blk_get_aio_context(blk), blk_aio_complete_bh, acb);
qemu_bh_schedule(acb->bh);
}
return &acb->common;
}
static void blk_aio_read_entry(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
BlkRwCo *rwco = &acb->rwco;
rwco->ret = blk_co_preadv(rwco->blk, rwco->offset, rwco->qiov->size,
rwco->qiov, rwco->flags);
blk_aio_complete(acb);
}
static void blk_aio_write_entry(void *opaque)
{
BlkAioEmAIOCB *acb = opaque;
BlkRwCo *rwco = &acb->rwco;
rwco->ret = blk_co_pwritev(rwco->blk, rwco->offset,
rwco->qiov ? rwco->qiov->size : 0,
rwco->qiov, rwco->flags);
blk_aio_complete(acb);
}
BlockAIOCB *blk_aio_write_zeroes(BlockBackend *blk, int64_t sector_num,
int nb_sectors, BdrvRequestFlags flags,
BlockCompletionFunc *cb, void *opaque)
{
if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return blk_abort_aio_request(blk, cb, opaque, -EINVAL);
}
return blk_aio_prwv(blk, sector_num << BDRV_SECTOR_BITS, NULL,
blk_aio_write_entry, BDRV_REQ_ZERO_WRITE, cb, opaque);
}
int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int count)
{
int ret = blk_prw(blk, offset, buf, count, blk_read_entry, 0);
if (ret < 0) {
return ret;
}
return count;
}
int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int count)
{
int ret = blk_prw(blk, offset, (void*) buf, count, blk_write_entry, 0);
if (ret < 0) {
return ret;
}
return count;
}
int64_t blk_getlength(BlockBackend *blk)
{
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_getlength(blk_bs(blk));
}
void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr)
{
if (!blk_bs(blk)) {
*nb_sectors_ptr = 0;
} else {
bdrv_get_geometry(blk_bs(blk), nb_sectors_ptr);
}
}
int64_t blk_nb_sectors(BlockBackend *blk)
{
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_nb_sectors(blk_bs(blk));
}
BlockAIOCB *blk_aio_readv(BlockBackend *blk, int64_t sector_num,
QEMUIOVector *iov, int nb_sectors,
BlockCompletionFunc *cb, void *opaque)
{
if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return blk_abort_aio_request(blk, cb, opaque, -EINVAL);
}
return blk_aio_prwv(blk, sector_num << BDRV_SECTOR_BITS, iov,
blk_aio_read_entry, 0, cb, opaque);
}
BlockAIOCB *blk_aio_writev(BlockBackend *blk, int64_t sector_num,
QEMUIOVector *iov, int nb_sectors,
BlockCompletionFunc *cb, void *opaque)
{
if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return blk_abort_aio_request(blk, cb, opaque, -EINVAL);
}
return blk_aio_prwv(blk, sector_num << BDRV_SECTOR_BITS, iov,
blk_aio_write_entry, 0, cb, opaque);
}
BlockAIOCB *blk_aio_flush(BlockBackend *blk,
BlockCompletionFunc *cb, void *opaque)
{
if (!blk_is_available(blk)) {
return blk_abort_aio_request(blk, cb, opaque, -ENOMEDIUM);
}
return bdrv_aio_flush(blk_bs(blk), cb, opaque);
}
BlockAIOCB *blk_aio_discard(BlockBackend *blk,
int64_t sector_num, int nb_sectors,
BlockCompletionFunc *cb, void *opaque)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return blk_abort_aio_request(blk, cb, opaque, ret);
}
return bdrv_aio_discard(blk_bs(blk), sector_num, nb_sectors, cb, opaque);
}
void blk_aio_cancel(BlockAIOCB *acb)
{
bdrv_aio_cancel(acb);
}
void blk_aio_cancel_async(BlockAIOCB *acb)
{
bdrv_aio_cancel_async(acb);
}
int blk_aio_multiwrite(BlockBackend *blk, BlockRequest *reqs, int num_reqs)
{
int i, ret;
for (i = 0; i < num_reqs; i++) {
ret = blk_check_request(blk, reqs[i].sector, reqs[i].nb_sectors);
if (ret < 0) {
return ret;
}
}
return bdrv_aio_multiwrite(blk_bs(blk), reqs, num_reqs);
}
int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf)
{
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_ioctl(blk_bs(blk), req, buf);
}
BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
BlockCompletionFunc *cb, void *opaque)
{
if (!blk_is_available(blk)) {
return blk_abort_aio_request(blk, cb, opaque, -ENOMEDIUM);
}
return bdrv_aio_ioctl(blk_bs(blk), req, buf, cb, opaque);
}
int blk_co_discard(BlockBackend *blk, int64_t sector_num, int nb_sectors)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return ret;
}
return bdrv_co_discard(blk_bs(blk), sector_num, nb_sectors);
}
int blk_co_flush(BlockBackend *blk)
{
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_co_flush(blk_bs(blk));
}
int blk_flush(BlockBackend *blk)
{
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_flush(blk_bs(blk));
}
void blk_drain(BlockBackend *blk)
{
if (blk_bs(blk)) {
bdrv_drain(blk_bs(blk));
}
}
void blk_drain_all(void)
{
bdrv_drain_all();
}
void blk_set_on_error(BlockBackend *blk, BlockdevOnError on_read_error,
BlockdevOnError on_write_error)
{
blk->on_read_error = on_read_error;
blk->on_write_error = on_write_error;
}
BlockdevOnError blk_get_on_error(BlockBackend *blk, bool is_read)
{
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);
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;
default:
abort();
}
}
static void send_qmp_error_event(BlockBackend *blk,
BlockErrorAction action,
bool is_read, int error)
{
IoOperationType optype;
optype = is_read ? IO_OPERATION_TYPE_READ : IO_OPERATION_TYPE_WRITE;
qapi_event_send_block_io_error(blk_name(blk), optype, action,
blk_iostatus_is_enabled(blk),
error == ENOSPC, strerror(error),
&error_abort);
}
/* 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);
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);
}
}
int blk_is_read_only(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
return bdrv_is_read_only(bs);
} else {
return blk->root_state.read_only;
}
}
int blk_is_sg(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
if (!bs) {
return 0;
}
return bdrv_is_sg(bs);
}
int blk_enable_write_cache(BlockBackend *blk)
{
return blk->enable_write_cache;
}
void blk_set_enable_write_cache(BlockBackend *blk, bool wce)
{
blk->enable_write_cache = wce;
}
void blk_invalidate_cache(BlockBackend *blk, Error **errp)
{
BlockDriverState *bs = blk_bs(blk);
if (!bs) {
error_setg(errp, "Device '%s' has no medium", blk->name);
return;
}
bdrv_invalidate_cache(bs, errp);
}
bool blk_is_inserted(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
return bs && bdrv_is_inserted(bs);
}
bool blk_is_available(BlockBackend *blk)
{
return blk_is_inserted(blk) && !blk_dev_is_tray_open(blk);
}
void blk_lock_medium(BlockBackend *blk, bool locked)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
bdrv_lock_medium(bs, locked);
}
}
void blk_eject(BlockBackend *blk, bool eject_flag)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
bdrv_eject(bs, eject_flag);
}
}
int blk_get_flags(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
return bdrv_get_flags(bs);
} else {
return blk->root_state.open_flags;
}
}
int blk_get_max_transfer_length(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
return bs->bl.max_transfer_length;
} else {
return 0;
}
}
int blk_get_max_iov(BlockBackend *blk)
{
return blk->root->bs->bl.max_iov;
}
void blk_set_guest_block_size(BlockBackend *blk, int align)
{
blk->guest_block_size = align;
}
void *blk_try_blockalign(BlockBackend *blk, size_t size)
{
return qemu_try_blockalign(blk ? blk_bs(blk) : NULL, size);
}
void *blk_blockalign(BlockBackend *blk, size_t size)
{
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);
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);
if (bs) {
bdrv_op_unblock(bs, op, reason);
}
}
void blk_op_block_all(BlockBackend *blk, Error *reason)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
bdrv_op_block_all(bs, reason);
}
}
void blk_op_unblock_all(BlockBackend *blk, Error *reason)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
bdrv_op_unblock_all(bs, reason);
}
}
AioContext *blk_get_aio_context(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
return bdrv_get_aio_context(bs);
} else {
return qemu_get_aio_context();
}
}
static AioContext *blk_aiocb_get_aio_context(BlockAIOCB *acb)
{
BlockBackendAIOCB *blk_acb = DO_UPCAST(BlockBackendAIOCB, common, acb);
return blk_get_aio_context(blk_acb->blk);
}
void blk_set_aio_context(BlockBackend *blk, AioContext *new_context)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
bdrv_set_aio_context(bs, new_context);
}
}
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)
{
BlockDriverState *bs = blk_bs(blk);
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)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
bdrv_remove_aio_context_notifier(bs, attached_aio_context,
detach_aio_context, opaque);
}
}
void blk_add_remove_bs_notifier(BlockBackend *blk, Notifier *notify)
{
notifier_list_add(&blk->remove_bs_notifiers, notify);
}
void blk_add_insert_bs_notifier(BlockBackend *blk, Notifier *notify)
{
notifier_list_add(&blk->insert_bs_notifiers, notify);
}
void blk_io_plug(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
bdrv_io_plug(bs);
}
}
void blk_io_unplug(BlockBackend *blk)
{
BlockDriverState *bs = blk_bs(blk);
if (bs) {
bdrv_io_unplug(bs);
}
}
BlockAcctStats *blk_get_stats(BlockBackend *blk)
{
return &blk->stats;
}
void *blk_aio_get(const AIOCBInfo *aiocb_info, BlockBackend *blk,
BlockCompletionFunc *cb, void *opaque)
{
return qemu_aio_get(aiocb_info, blk_bs(blk), cb, opaque);
}
int coroutine_fn blk_co_write_zeroes(BlockBackend *blk, int64_t sector_num,
int nb_sectors, BdrvRequestFlags flags)
{
if (nb_sectors < 0 || nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
return -EINVAL;
}
return blk_co_pwritev(blk, sector_num << BDRV_SECTOR_BITS,
nb_sectors << BDRV_SECTOR_BITS, NULL,
BDRV_REQ_ZERO_WRITE);
}
int blk_write_compressed(BlockBackend *blk, int64_t sector_num,
const uint8_t *buf, int nb_sectors)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return ret;
}
return bdrv_write_compressed(blk_bs(blk), sector_num, buf, nb_sectors);
}
int blk_truncate(BlockBackend *blk, int64_t offset)
{
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_truncate(blk_bs(blk), offset);
}
int blk_discard(BlockBackend *blk, int64_t sector_num, int nb_sectors)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return ret;
}
return bdrv_discard(blk_bs(blk), sector_num, nb_sectors);
}
int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf,
int64_t pos, int size)
{
int ret;
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)
{
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)
{
if (!blk_is_available(blk)) {
return -ENOMEDIUM;
}
return bdrv_probe_blocksizes(blk_bs(blk), bsz);
}
int blk_probe_geometry(BlockBackend *blk, HDGeometry *geo)
{
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)
{
assert(blk->root);
blk->root_state.open_flags = blk->root->bs->open_flags;
blk->root_state.read_only = blk->root->bs->read_only;
blk->root_state.detect_zeroes = blk->root->bs->detect_zeroes;
if (blk->root_state.throttle_group) {
g_free(blk->root_state.throttle_group);
throttle_group_unref(blk->root_state.throttle_state);
}
if (blk->root->bs->throttle_state) {
const char *name = throttle_group_get_name(blk->root->bs);
blk->root_state.throttle_group = g_strdup(name);
blk->root_state.throttle_state = throttle_group_incref(name);
} else {
blk->root_state.throttle_group = NULL;
blk->root_state.throttle_state = NULL;
}
}
/*
* Applies the information in the root state to the given BlockDriverState. This
* does not include the flags which have to be specified for bdrv_open(), use
* blk_get_open_flags_from_root_state() to inquire them.
*/
void blk_apply_root_state(BlockBackend *blk, BlockDriverState *bs)
{
bs->detect_zeroes = blk->root_state.detect_zeroes;
if (blk->root_state.throttle_group) {
bdrv_io_limits_enable(bs, blk->root_state.throttle_group);
}
}
/*
* 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)
{
int bs_flags;
bs_flags = blk->root_state.read_only ? 0 : BDRV_O_RDWR;
bs_flags |= blk->root_state.open_flags & ~BDRV_O_RDWR;
return bs_flags;
}
BlockBackendRootState *blk_get_root_state(BlockBackend *blk)
{
return &blk->root_state;
}
int blk_commit_all(void)
{
BlockBackend *blk = NULL;
while ((blk = blk_all_next(blk)) != NULL) {
AioContext *aio_context = blk_get_aio_context(blk);
aio_context_acquire(aio_context);
if (blk_is_inserted(blk) && blk->root->bs->backing) {
int ret = bdrv_commit(blk->root->bs);
if (ret < 0) {
aio_context_release(aio_context);
return ret;
}
}
aio_context_release(aio_context);
}
return 0;
}
int blk_flush_all(void)
{
BlockBackend *blk = NULL;
int result = 0;
while ((blk = blk_all_next(blk)) != NULL) {
AioContext *aio_context = blk_get_aio_context(blk);
int ret;
aio_context_acquire(aio_context);
if (blk_is_inserted(blk)) {
ret = blk_flush(blk);
if (ret < 0 && !result) {
result = ret;
}
}
aio_context_release(aio_context);
}
return result;
}
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