qemu/block/block-backend.c

916 lines
22 KiB
C

/*
* 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 "sysemu/block-backend.h"
#include "block/block_int.h"
#include "sysemu/blockdev.h"
#include "qapi-event.h"
/* Number of coroutines to reserve per attached device model */
#define COROUTINE_POOL_RESERVATION 64
struct BlockBackend {
char *name;
int refcnt;
BlockDriverState *bs;
DriveInfo *legacy_dinfo; /* null unless created by drive_new() */
QTAILQ_ENTRY(BlockBackend) link; /* for blk_backends */
void *dev; /* attached device model, if any */
/* TODO change to DeviceState when all users are qdevified */
const BlockDevOps *dev_ops;
void *dev_opaque;
};
typedef struct BlockBackendAIOCB {
BlockAIOCB common;
QEMUBH *bh;
int ret;
} BlockBackendAIOCB;
static const AIOCBInfo block_backend_aiocb_info = {
.aiocb_size = sizeof(BlockBackendAIOCB),
};
static void drive_info_del(DriveInfo *dinfo);
/* All the BlockBackends (except for hidden ones) */
static QTAILQ_HEAD(, BlockBackend) blk_backends =
QTAILQ_HEAD_INITIALIZER(blk_backends);
/*
* Create a new BlockBackend with @name, with a reference count of one.
* @name must not be null or empty.
* Fail if a BlockBackend with this name already exists.
* Store an error through @errp on failure, unless it's null.
* Return the new BlockBackend on success, null on failure.
*/
BlockBackend *blk_new(const char *name, Error **errp)
{
BlockBackend *blk;
assert(name && name[0]);
if (!id_wellformed(name)) {
error_setg(errp, "Invalid device name");
return NULL;
}
if (blk_by_name(name)) {
error_setg(errp, "Device with id '%s' already exists", name);
return NULL;
}
if (bdrv_find_node(name)) {
error_setg(errp,
"Device name '%s' conflicts with an existing node name",
name);
return NULL;
}
blk = g_new0(BlockBackend, 1);
blk->name = g_strdup(name);
blk->refcnt = 1;
QTAILQ_INSERT_TAIL(&blk_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(const char *name, Error **errp)
{
BlockBackend *blk;
BlockDriverState *bs;
blk = blk_new(name, errp);
if (!blk) {
return NULL;
}
bs = bdrv_new_root();
blk->bs = bs;
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 *name, const char *filename,
const char *reference, QDict *options, int flags,
Error **errp)
{
BlockBackend *blk;
int ret;
blk = blk_new_with_bs(name, errp);
if (!blk) {
QDECREF(options);
return NULL;
}
ret = bdrv_open(&blk->bs, filename, reference, options, flags, NULL, errp);
if (ret < 0) {
blk_unref(blk);
return NULL;
}
return blk;
}
static void blk_delete(BlockBackend *blk)
{
assert(!blk->refcnt);
assert(!blk->dev);
if (blk->bs) {
assert(blk->bs->blk == blk);
blk->bs->blk = NULL;
bdrv_unref(blk->bs);
blk->bs = NULL;
}
/* Avoid double-remove after blk_hide_on_behalf_of_hmp_drive_del() */
if (blk->name[0]) {
QTAILQ_REMOVE(&blk_backends, blk, link);
}
g_free(blk->name);
drive_info_del(blk->legacy_dinfo);
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);
}
/*
* 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);
}
}
}
/*
* Return the 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, link) : QTAILQ_FIRST(&blk_backends);
}
/*
* Return @blk's name, a non-null string.
* Wart: the name is empty iff @blk has been hidden with
* blk_hide_on_behalf_of_hmp_drive_del().
*/
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;
assert(name);
QTAILQ_FOREACH(blk, &blk_backends, link) {
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->bs;
}
/*
* 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;
QTAILQ_FOREACH(blk, &blk_backends, link) {
if (blk->legacy_dinfo == dinfo) {
return blk;
}
}
abort();
}
/*
* Hide @blk.
* @blk must not have been hidden already.
* Make attached BlockDriverState, if any, anonymous.
* Once hidden, @blk is invisible to all functions that don't receive
* it as argument. For example, blk_by_name() won't return it.
* Strictly for use by do_drive_del().
* TODO get rid of it!
*/
void blk_hide_on_behalf_of_hmp_drive_del(BlockBackend *blk)
{
QTAILQ_REMOVE(&blk_backends, blk, link);
blk->name[0] = 0;
if (blk->bs) {
bdrv_make_anon(blk->bs);
}
}
/*
* 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;
bdrv_iostatus_reset(blk->bs);
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;
bdrv_set_guest_block_size(blk->bs, 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_closed = !blk_dev_is_tray_open(blk);
blk->dev_ops->change_media_cb(blk->dev_opaque, load);
if (tray_was_closed) {
/* tray open */
qapi_event_send_device_tray_moved(blk_name(blk),
true, &error_abort);
}
if (load) {
/* tray close */
qapi_event_send_device_tray_moved(blk_name(blk),
false, &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);
}
/*
* 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_ops && blk->dev_ops->is_tray_open) {
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)
{
bdrv_iostatus_enable(blk->bs);
}
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_inserted(blk)) {
return -ENOMEDIUM;
}
len = blk_getlength(blk);
if (len < 0) {
return len;
}
if (offset < 0) {
return -EIO;
}
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);
}
int blk_read(BlockBackend *blk, int64_t sector_num, uint8_t *buf,
int nb_sectors)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return ret;
}
return bdrv_read(blk->bs, sector_num, buf, nb_sectors);
}
int blk_read_unthrottled(BlockBackend *blk, int64_t sector_num, uint8_t *buf,
int nb_sectors)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return ret;
}
return bdrv_read_unthrottled(blk->bs, sector_num, buf, nb_sectors);
}
int blk_write(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(blk->bs, sector_num, buf, nb_sectors);
}
int blk_write_zeroes(BlockBackend *blk, int64_t sector_num,
int nb_sectors, BdrvRequestFlags flags)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return ret;
}
return bdrv_write_zeroes(blk->bs, sector_num, nb_sectors, flags);
}
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);
}
static BlockAIOCB *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->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;
}
BlockAIOCB *blk_aio_write_zeroes(BlockBackend *blk, int64_t sector_num,
int nb_sectors, BdrvRequestFlags flags,
BlockCompletionFunc *cb, void *opaque)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return abort_aio_request(blk, cb, opaque, ret);
}
return bdrv_aio_write_zeroes(blk->bs, sector_num, nb_sectors, flags,
cb, opaque);
}
int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int count)
{
int ret = blk_check_byte_request(blk, offset, count);
if (ret < 0) {
return ret;
}
return bdrv_pread(blk->bs, offset, buf, count);
}
int blk_pwrite(BlockBackend *blk, int64_t offset, const void *buf, int count)
{
int ret = blk_check_byte_request(blk, offset, count);
if (ret < 0) {
return ret;
}
return bdrv_pwrite(blk->bs, offset, buf, count);
}
int64_t blk_getlength(BlockBackend *blk)
{
return bdrv_getlength(blk->bs);
}
void blk_get_geometry(BlockBackend *blk, uint64_t *nb_sectors_ptr)
{
bdrv_get_geometry(blk->bs, nb_sectors_ptr);
}
int64_t blk_nb_sectors(BlockBackend *blk)
{
return bdrv_nb_sectors(blk->bs);
}
BlockAIOCB *blk_aio_readv(BlockBackend *blk, int64_t sector_num,
QEMUIOVector *iov, int nb_sectors,
BlockCompletionFunc *cb, void *opaque)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return abort_aio_request(blk, cb, opaque, ret);
}
return bdrv_aio_readv(blk->bs, sector_num, iov, nb_sectors, cb, opaque);
}
BlockAIOCB *blk_aio_writev(BlockBackend *blk, int64_t sector_num,
QEMUIOVector *iov, int nb_sectors,
BlockCompletionFunc *cb, void *opaque)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return abort_aio_request(blk, cb, opaque, ret);
}
return bdrv_aio_writev(blk->bs, sector_num, iov, nb_sectors, cb, opaque);
}
BlockAIOCB *blk_aio_flush(BlockBackend *blk,
BlockCompletionFunc *cb, void *opaque)
{
return bdrv_aio_flush(blk->bs, 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 abort_aio_request(blk, cb, opaque, ret);
}
return bdrv_aio_discard(blk->bs, 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, reqs, num_reqs);
}
int blk_ioctl(BlockBackend *blk, unsigned long int req, void *buf)
{
return bdrv_ioctl(blk->bs, req, buf);
}
BlockAIOCB *blk_aio_ioctl(BlockBackend *blk, unsigned long int req, void *buf,
BlockCompletionFunc *cb, void *opaque)
{
return bdrv_aio_ioctl(blk->bs, 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, sector_num, nb_sectors);
}
int blk_co_flush(BlockBackend *blk)
{
return bdrv_co_flush(blk->bs);
}
int blk_flush(BlockBackend *blk)
{
return bdrv_flush(blk->bs);
}
int blk_flush_all(void)
{
return bdrv_flush_all();
}
void blk_drain_all(void)
{
bdrv_drain_all();
}
BlockdevOnError blk_get_on_error(BlockBackend *blk, bool is_read)
{
return bdrv_get_on_error(blk->bs, is_read);
}
BlockErrorAction blk_get_error_action(BlockBackend *blk, bool is_read,
int error)
{
return bdrv_get_error_action(blk->bs, is_read, error);
}
void blk_error_action(BlockBackend *blk, BlockErrorAction action,
bool is_read, int error)
{
bdrv_error_action(blk->bs, action, is_read, error);
}
int blk_is_read_only(BlockBackend *blk)
{
return bdrv_is_read_only(blk->bs);
}
int blk_is_sg(BlockBackend *blk)
{
return bdrv_is_sg(blk->bs);
}
int blk_enable_write_cache(BlockBackend *blk)
{
return bdrv_enable_write_cache(blk->bs);
}
void blk_set_enable_write_cache(BlockBackend *blk, bool wce)
{
bdrv_set_enable_write_cache(blk->bs, wce);
}
void blk_invalidate_cache(BlockBackend *blk, Error **errp)
{
bdrv_invalidate_cache(blk->bs, errp);
}
int blk_is_inserted(BlockBackend *blk)
{
return bdrv_is_inserted(blk->bs);
}
void blk_lock_medium(BlockBackend *blk, bool locked)
{
bdrv_lock_medium(blk->bs, locked);
}
void blk_eject(BlockBackend *blk, bool eject_flag)
{
bdrv_eject(blk->bs, eject_flag);
}
int blk_get_flags(BlockBackend *blk)
{
return bdrv_get_flags(blk->bs);
}
int blk_get_max_transfer_length(BlockBackend *blk)
{
return blk->bs->bl.max_transfer_length;
}
void blk_set_guest_block_size(BlockBackend *blk, int align)
{
bdrv_set_guest_block_size(blk->bs, align);
}
void *blk_blockalign(BlockBackend *blk, size_t size)
{
return qemu_blockalign(blk ? blk->bs : NULL, size);
}
bool blk_op_is_blocked(BlockBackend *blk, BlockOpType op, Error **errp)
{
return bdrv_op_is_blocked(blk->bs, op, errp);
}
void blk_op_unblock(BlockBackend *blk, BlockOpType op, Error *reason)
{
bdrv_op_unblock(blk->bs, op, reason);
}
void blk_op_block_all(BlockBackend *blk, Error *reason)
{
bdrv_op_block_all(blk->bs, reason);
}
void blk_op_unblock_all(BlockBackend *blk, Error *reason)
{
bdrv_op_unblock_all(blk->bs, reason);
}
AioContext *blk_get_aio_context(BlockBackend *blk)
{
return bdrv_get_aio_context(blk->bs);
}
void blk_set_aio_context(BlockBackend *blk, AioContext *new_context)
{
bdrv_set_aio_context(blk->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)
{
bdrv_add_aio_context_notifier(blk->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)
{
bdrv_remove_aio_context_notifier(blk->bs, attached_aio_context,
detach_aio_context, opaque);
}
void blk_add_close_notifier(BlockBackend *blk, Notifier *notify)
{
bdrv_add_close_notifier(blk->bs, notify);
}
void blk_io_plug(BlockBackend *blk)
{
bdrv_io_plug(blk->bs);
}
void blk_io_unplug(BlockBackend *blk)
{
bdrv_io_unplug(blk->bs);
}
BlockAcctStats *blk_get_stats(BlockBackend *blk)
{
return bdrv_get_stats(blk->bs);
}
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)
{
int ret = blk_check_request(blk, sector_num, nb_sectors);
if (ret < 0) {
return ret;
}
return bdrv_co_write_zeroes(blk->bs, sector_num, nb_sectors, flags);
}
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, sector_num, buf, nb_sectors);
}
int blk_truncate(BlockBackend *blk, int64_t offset)
{
return bdrv_truncate(blk->bs, 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, sector_num, nb_sectors);
}
int blk_save_vmstate(BlockBackend *blk, const uint8_t *buf,
int64_t pos, int size)
{
return bdrv_save_vmstate(blk->bs, buf, pos, size);
}
int blk_load_vmstate(BlockBackend *blk, uint8_t *buf, int64_t pos, int size)
{
return bdrv_load_vmstate(blk->bs, buf, pos, size);
}
int blk_probe_blocksizes(BlockBackend *blk, BlockSizes *bsz)
{
return bdrv_probe_blocksizes(blk->bs, bsz);
}
int blk_probe_geometry(BlockBackend *blk, HDGeometry *geo)
{
return bdrv_probe_geometry(blk->bs, geo);
}