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xemu/blockdev.c
Christoph Hellwig a659979328 block: clarify the meaning of BDRV_O_NOCACHE 
Change BDRV_O_NOCACHE to only imply bypassing the host OS file cache,
but no writeback semantics.  All existing callers are changed to also
specify BDRV_O_CACHE_WB to give them writeback semantics.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2011-06-08 10:39:32 +02:00

800 lines
21 KiB
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/*
* QEMU host block devices
*
* Copyright (c) 2003-2008 Fabrice Bellard
*
* This work is licensed under the terms of the GNU GPL, version 2 or
* later. See the COPYING file in the top-level directory.
*/
#include "block.h"
#include "blockdev.h"
#include "monitor.h"
#include "qerror.h"
#include "qemu-option.h"
#include "qemu-config.h"
#include "sysemu.h"
#include "hw/qdev.h"
#include "block_int.h"
static QTAILQ_HEAD(drivelist, DriveInfo) drives = QTAILQ_HEAD_INITIALIZER(drives);
static const char *const if_name[IF_COUNT] = {
[IF_NONE] = "none",
[IF_IDE] = "ide",
[IF_SCSI] = "scsi",
[IF_FLOPPY] = "floppy",
[IF_PFLASH] = "pflash",
[IF_MTD] = "mtd",
[IF_SD] = "sd",
[IF_VIRTIO] = "virtio",
[IF_XEN] = "xen",
};
static const int if_max_devs[IF_COUNT] = {
/*
* Do not change these numbers! They govern how drive option
* index maps to unit and bus. That mapping is ABI.
*
* All controllers used to imlement if=T drives need to support
* if_max_devs[T] units, for any T with if_max_devs[T] != 0.
* Otherwise, some index values map to "impossible" bus, unit
* values.
*
* For instance, if you change [IF_SCSI] to 255, -drive
* if=scsi,index=12 no longer means bus=1,unit=5, but
* bus=0,unit=12. With an lsi53c895a controller (7 units max),
* the drive can't be set up. Regression.
*/
[IF_IDE] = 2,
[IF_SCSI] = 7,
};
/*
* We automatically delete the drive when a device using it gets
* unplugged. Questionable feature, but we can't just drop it.
* Device models call blockdev_mark_auto_del() to schedule the
* automatic deletion, and generic qdev code calls blockdev_auto_del()
* when deletion is actually safe.
*/
void blockdev_mark_auto_del(BlockDriverState *bs)
{
DriveInfo *dinfo = drive_get_by_blockdev(bs);
if (dinfo) {
dinfo->auto_del = 1;
}
}
void blockdev_auto_del(BlockDriverState *bs)
{
DriveInfo *dinfo = drive_get_by_blockdev(bs);
if (dinfo && dinfo->auto_del) {
drive_put_ref(dinfo);
}
}
static int drive_index_to_bus_id(BlockInterfaceType type, int index)
{
int max_devs = if_max_devs[type];
return max_devs ? index / max_devs : 0;
}
static int drive_index_to_unit_id(BlockInterfaceType type, int index)
{
int max_devs = if_max_devs[type];
return max_devs ? index % max_devs : index;
}
QemuOpts *drive_def(const char *optstr)
{
return qemu_opts_parse(qemu_find_opts("drive"), optstr, 0);
}
QemuOpts *drive_add(BlockInterfaceType type, int index, const char *file,
const char *optstr)
{
QemuOpts *opts;
char buf[32];
opts = drive_def(optstr);
if (!opts) {
return NULL;
}
if (type != IF_DEFAULT) {
qemu_opt_set(opts, "if", if_name[type]);
}
if (index >= 0) {
snprintf(buf, sizeof(buf), "%d", index);
qemu_opt_set(opts, "index", buf);
}
if (file)
qemu_opt_set(opts, "file", file);
return opts;
}
DriveInfo *drive_get(BlockInterfaceType type, int bus, int unit)
{
DriveInfo *dinfo;
/* seek interface, bus and unit */
QTAILQ_FOREACH(dinfo, &drives, next) {
if (dinfo->type == type &&
dinfo->bus == bus &&
dinfo->unit == unit)
return dinfo;
}
return NULL;
}
DriveInfo *drive_get_by_index(BlockInterfaceType type, int index)
{
return drive_get(type,
drive_index_to_bus_id(type, index),
drive_index_to_unit_id(type, index));
}
int drive_get_max_bus(BlockInterfaceType type)
{
int max_bus;
DriveInfo *dinfo;
max_bus = -1;
QTAILQ_FOREACH(dinfo, &drives, next) {
if(dinfo->type == type &&
dinfo->bus > max_bus)
max_bus = dinfo->bus;
}
return max_bus;
}
/* Get a block device. This should only be used for single-drive devices
(e.g. SD/Floppy/MTD). Multi-disk devices (scsi/ide) should use the
appropriate bus. */
DriveInfo *drive_get_next(BlockInterfaceType type)
{
static int next_block_unit[IF_COUNT];
return drive_get(type, 0, next_block_unit[type]++);
}
DriveInfo *drive_get_by_blockdev(BlockDriverState *bs)
{
DriveInfo *dinfo;
QTAILQ_FOREACH(dinfo, &drives, next) {
if (dinfo->bdrv == bs) {
return dinfo;
}
}
return NULL;
}
static void bdrv_format_print(void *opaque, const char *name)
{
error_printf(" %s", name);
}
static void drive_uninit(DriveInfo *dinfo)
{
qemu_opts_del(dinfo->opts);
bdrv_delete(dinfo->bdrv);
qemu_free(dinfo->id);
QTAILQ_REMOVE(&drives, dinfo, next);
qemu_free(dinfo);
}
void drive_put_ref(DriveInfo *dinfo)
{
assert(dinfo->refcount);
if (--dinfo->refcount == 0) {
drive_uninit(dinfo);
}
}
void drive_get_ref(DriveInfo *dinfo)
{
dinfo->refcount++;
}
static int parse_block_error_action(const char *buf, int is_read)
{
if (!strcmp(buf, "ignore")) {
return BLOCK_ERR_IGNORE;
} else if (!is_read && !strcmp(buf, "enospc")) {
return BLOCK_ERR_STOP_ENOSPC;
} else if (!strcmp(buf, "stop")) {
return BLOCK_ERR_STOP_ANY;
} else if (!strcmp(buf, "report")) {
return BLOCK_ERR_REPORT;
} else {
error_report("'%s' invalid %s error action",
buf, is_read ? "read" : "write");
return -1;
}
}
DriveInfo *drive_init(QemuOpts *opts, int default_to_scsi)
{
const char *buf;
const char *file = NULL;
char devname[128];
const char *serial;
const char *mediastr = "";
BlockInterfaceType type;
enum { MEDIA_DISK, MEDIA_CDROM } media;
int bus_id, unit_id;
int cyls, heads, secs, translation;
BlockDriver *drv = NULL;
int max_devs;
int index;
int ro = 0;
int bdrv_flags = 0;
int on_read_error, on_write_error;
const char *devaddr;
DriveInfo *dinfo;
int snapshot = 0;
int ret;
translation = BIOS_ATA_TRANSLATION_AUTO;
if (default_to_scsi) {
type = IF_SCSI;
pstrcpy(devname, sizeof(devname), "scsi");
} else {
type = IF_IDE;
pstrcpy(devname, sizeof(devname), "ide");
}
media = MEDIA_DISK;
/* extract parameters */
bus_id = qemu_opt_get_number(opts, "bus", 0);
unit_id = qemu_opt_get_number(opts, "unit", -1);
index = qemu_opt_get_number(opts, "index", -1);
cyls = qemu_opt_get_number(opts, "cyls", 0);
heads = qemu_opt_get_number(opts, "heads", 0);
secs = qemu_opt_get_number(opts, "secs", 0);
snapshot = qemu_opt_get_bool(opts, "snapshot", 0);
ro = qemu_opt_get_bool(opts, "readonly", 0);
file = qemu_opt_get(opts, "file");
serial = qemu_opt_get(opts, "serial");
if ((buf = qemu_opt_get(opts, "if")) != NULL) {
pstrcpy(devname, sizeof(devname), buf);
for (type = 0; type < IF_COUNT && strcmp(buf, if_name[type]); type++)
;
if (type == IF_COUNT) {
error_report("unsupported bus type '%s'", buf);
return NULL;
}
}
max_devs = if_max_devs[type];
if (cyls || heads || secs) {
if (cyls < 1 || (type == IF_IDE && cyls > 16383)) {
error_report("invalid physical cyls number");
return NULL;
}
if (heads < 1 || (type == IF_IDE && heads > 16)) {
error_report("invalid physical heads number");
return NULL;
}
if (secs < 1 || (type == IF_IDE && secs > 63)) {
error_report("invalid physical secs number");
return NULL;
}
}
if ((buf = qemu_opt_get(opts, "trans")) != NULL) {
if (!cyls) {
error_report("'%s' trans must be used with cyls,heads and secs",
buf);
return NULL;
}
if (!strcmp(buf, "none"))
translation = BIOS_ATA_TRANSLATION_NONE;
else if (!strcmp(buf, "lba"))
translation = BIOS_ATA_TRANSLATION_LBA;
else if (!strcmp(buf, "auto"))
translation = BIOS_ATA_TRANSLATION_AUTO;
else {
error_report("'%s' invalid translation type", buf);
return NULL;
}
}
if ((buf = qemu_opt_get(opts, "media")) != NULL) {
if (!strcmp(buf, "disk")) {
media = MEDIA_DISK;
} else if (!strcmp(buf, "cdrom")) {
if (cyls || secs || heads) {
error_report("'%s' invalid physical CHS format", buf);
return NULL;
}
media = MEDIA_CDROM;
} else {
error_report("'%s' invalid media", buf);
return NULL;
}
}
if ((buf = qemu_opt_get(opts, "cache")) != NULL) {
if (!strcmp(buf, "off") || !strcmp(buf, "none")) {
bdrv_flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB;
} else if (!strcmp(buf, "writeback")) {
bdrv_flags |= BDRV_O_CACHE_WB;
} else if (!strcmp(buf, "unsafe")) {
bdrv_flags |= BDRV_O_CACHE_WB;
bdrv_flags |= BDRV_O_NO_FLUSH;
} else if (!strcmp(buf, "writethrough")) {
/* this is the default */
} else {
error_report("invalid cache option");
return NULL;
}
}
#ifdef CONFIG_LINUX_AIO
if ((buf = qemu_opt_get(opts, "aio")) != NULL) {
if (!strcmp(buf, "native")) {
bdrv_flags |= BDRV_O_NATIVE_AIO;
} else if (!strcmp(buf, "threads")) {
/* this is the default */
} else {
error_report("invalid aio option");
return NULL;
}
}
#endif
if ((buf = qemu_opt_get(opts, "format")) != NULL) {
if (strcmp(buf, "?") == 0) {
error_printf("Supported formats:");
bdrv_iterate_format(bdrv_format_print, NULL);
error_printf("\n");
return NULL;
}
drv = bdrv_find_whitelisted_format(buf);
if (!drv) {
error_report("'%s' invalid format", buf);
return NULL;
}
}
on_write_error = BLOCK_ERR_STOP_ENOSPC;
if ((buf = qemu_opt_get(opts, "werror")) != NULL) {
if (type != IF_IDE && type != IF_SCSI && type != IF_VIRTIO && type != IF_NONE) {
error_report("werror is not supported by this bus type");
return NULL;
}
on_write_error = parse_block_error_action(buf, 0);
if (on_write_error < 0) {
return NULL;
}
}
on_read_error = BLOCK_ERR_REPORT;
if ((buf = qemu_opt_get(opts, "rerror")) != NULL) {
if (type != IF_IDE && type != IF_VIRTIO && type != IF_SCSI && type != IF_NONE) {
error_report("rerror is not supported by this bus type");
return NULL;
}
on_read_error = parse_block_error_action(buf, 1);
if (on_read_error < 0) {
return NULL;
}
}
if ((devaddr = qemu_opt_get(opts, "addr")) != NULL) {
if (type != IF_VIRTIO) {
error_report("addr is not supported by this bus type");
return NULL;
}
}
/* compute bus and unit according index */
if (index != -1) {
if (bus_id != 0 || unit_id != -1) {
error_report("index cannot be used with bus and unit");
return NULL;
}
bus_id = drive_index_to_bus_id(type, index);
unit_id = drive_index_to_unit_id(type, index);
}
/* if user doesn't specify a unit_id,
* try to find the first free
*/
if (unit_id == -1) {
unit_id = 0;
while (drive_get(type, bus_id, unit_id) != NULL) {
unit_id++;
if (max_devs && unit_id >= max_devs) {
unit_id -= max_devs;
bus_id++;
}
}
}
/* check unit id */
if (max_devs && unit_id >= max_devs) {
error_report("unit %d too big (max is %d)",
unit_id, max_devs - 1);
return NULL;
}
/*
* catch multiple definitions
*/
if (drive_get(type, bus_id, unit_id) != NULL) {
error_report("drive with bus=%d, unit=%d (index=%d) exists",
bus_id, unit_id, index);
return NULL;
}
/* init */
dinfo = qemu_mallocz(sizeof(*dinfo));
if ((buf = qemu_opts_id(opts)) != NULL) {
dinfo->id = qemu_strdup(buf);
} else {
/* no id supplied -> create one */
dinfo->id = qemu_mallocz(32);
if (type == IF_IDE || type == IF_SCSI)
mediastr = (media == MEDIA_CDROM) ? "-cd" : "-hd";
if (max_devs)
snprintf(dinfo->id, 32, "%s%i%s%i",
devname, bus_id, mediastr, unit_id);
else
snprintf(dinfo->id, 32, "%s%s%i",
devname, mediastr, unit_id);
}
dinfo->bdrv = bdrv_new(dinfo->id);
dinfo->devaddr = devaddr;
dinfo->type = type;
dinfo->bus = bus_id;
dinfo->unit = unit_id;
dinfo->opts = opts;
dinfo->refcount = 1;
if (serial)
strncpy(dinfo->serial, serial, sizeof(dinfo->serial) - 1);
QTAILQ_INSERT_TAIL(&drives, dinfo, next);
bdrv_set_on_error(dinfo->bdrv, on_read_error, on_write_error);
switch(type) {
case IF_IDE:
case IF_SCSI:
case IF_XEN:
case IF_NONE:
switch(media) {
case MEDIA_DISK:
if (cyls != 0) {
bdrv_set_geometry_hint(dinfo->bdrv, cyls, heads, secs);
bdrv_set_translation_hint(dinfo->bdrv, translation);
}
break;
case MEDIA_CDROM:
bdrv_set_removable(dinfo->bdrv, 1);
dinfo->media_cd = 1;
break;
}
break;
case IF_SD:
/* FIXME: This isn't really a floppy, but it's a reasonable
approximation. */
case IF_FLOPPY:
bdrv_set_removable(dinfo->bdrv, 1);
break;
case IF_PFLASH:
case IF_MTD:
break;
case IF_VIRTIO:
/* add virtio block device */
opts = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
qemu_opt_set(opts, "driver", "virtio-blk");
qemu_opt_set(opts, "drive", dinfo->id);
if (devaddr)
qemu_opt_set(opts, "addr", devaddr);
break;
default:
abort();
}
if (!file || !*file) {
return dinfo;
}
if (snapshot) {
/* always use cache=unsafe with snapshot */
bdrv_flags &= ~BDRV_O_CACHE_MASK;
bdrv_flags |= (BDRV_O_SNAPSHOT|BDRV_O_CACHE_WB|BDRV_O_NO_FLUSH);
}
if (media == MEDIA_CDROM) {
/* CDROM is fine for any interface, don't check. */
ro = 1;
} else if (ro == 1) {
if (type != IF_SCSI && type != IF_VIRTIO && type != IF_FLOPPY && type != IF_NONE) {
error_report("readonly not supported by this bus type");
goto err;
}
}
bdrv_flags |= ro ? 0 : BDRV_O_RDWR;
ret = bdrv_open(dinfo->bdrv, file, bdrv_flags, drv);
if (ret < 0) {
error_report("could not open disk image %s: %s",
file, strerror(-ret));
goto err;
}
if (bdrv_key_required(dinfo->bdrv))
autostart = 0;
return dinfo;
err:
bdrv_delete(dinfo->bdrv);
qemu_free(dinfo->id);
QTAILQ_REMOVE(&drives, dinfo, next);
qemu_free(dinfo);
return NULL;
}
void do_commit(Monitor *mon, const QDict *qdict)
{
const char *device = qdict_get_str(qdict, "device");
BlockDriverState *bs;
if (!strcmp(device, "all")) {
bdrv_commit_all();
} else {
bs = bdrv_find(device);
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, device);
return;
}
bdrv_commit(bs);
}
}
int do_snapshot_blkdev(Monitor *mon, const QDict *qdict, QObject **ret_data)
{
const char *device = qdict_get_str(qdict, "device");
const char *filename = qdict_get_try_str(qdict, "snapshot_file");
const char *format = qdict_get_try_str(qdict, "format");
BlockDriverState *bs;
BlockDriver *drv, *old_drv, *proto_drv;
int ret = 0;
int flags;
char old_filename[1024];
if (!filename) {
qerror_report(QERR_MISSING_PARAMETER, "snapshot_file");
ret = -1;
goto out;
}
bs = bdrv_find(device);
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, device);
ret = -1;
goto out;
}
pstrcpy(old_filename, sizeof(old_filename), bs->filename);
old_drv = bs->drv;
flags = bs->open_flags;
if (!format) {
format = "qcow2";
}
drv = bdrv_find_format(format);
if (!drv) {
qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
ret = -1;
goto out;
}
proto_drv = bdrv_find_protocol(filename);
if (!proto_drv) {
qerror_report(QERR_INVALID_BLOCK_FORMAT, format);
ret = -1;
goto out;
}
ret = bdrv_img_create(filename, format, bs->filename,
bs->drv->format_name, NULL, -1, flags);
if (ret) {
goto out;
}
qemu_aio_flush();
bdrv_flush(bs);
bdrv_close(bs);
ret = bdrv_open(bs, filename, flags, drv);
/*
* If reopening the image file we just created fails, fall back
* and try to re-open the original image. If that fails too, we
* are in serious trouble.
*/
if (ret != 0) {
ret = bdrv_open(bs, old_filename, flags, old_drv);
if (ret != 0) {
qerror_report(QERR_OPEN_FILE_FAILED, old_filename);
} else {
qerror_report(QERR_OPEN_FILE_FAILED, filename);
}
}
out:
if (ret) {
ret = -1;
}
return ret;
}
static int eject_device(Monitor *mon, BlockDriverState *bs, int force)
{
if (!force) {
if (!bdrv_is_removable(bs)) {
qerror_report(QERR_DEVICE_NOT_REMOVABLE,
bdrv_get_device_name(bs));
return -1;
}
if (bdrv_is_locked(bs)) {
qerror_report(QERR_DEVICE_LOCKED, bdrv_get_device_name(bs));
return -1;
}
}
bdrv_close(bs);
return 0;
}
int do_eject(Monitor *mon, const QDict *qdict, QObject **ret_data)
{
BlockDriverState *bs;
int force = qdict_get_try_bool(qdict, "force", 0);
const char *filename = qdict_get_str(qdict, "device");
bs = bdrv_find(filename);
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, filename);
return -1;
}
return eject_device(mon, bs, force);
}
int do_block_set_passwd(Monitor *mon, const QDict *qdict,
QObject **ret_data)
{
BlockDriverState *bs;
int err;
bs = bdrv_find(qdict_get_str(qdict, "device"));
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, qdict_get_str(qdict, "device"));
return -1;
}
err = bdrv_set_key(bs, qdict_get_str(qdict, "password"));
if (err == -EINVAL) {
qerror_report(QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
return -1;
} else if (err < 0) {
qerror_report(QERR_INVALID_PASSWORD);
return -1;
}
return 0;
}
int do_change_block(Monitor *mon, const char *device,
const char *filename, const char *fmt)
{
BlockDriverState *bs;
BlockDriver *drv = NULL;
int bdrv_flags;
bs = bdrv_find(device);
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, device);
return -1;
}
if (fmt) {
drv = bdrv_find_whitelisted_format(fmt);
if (!drv) {
qerror_report(QERR_INVALID_BLOCK_FORMAT, fmt);
return -1;
}
}
if (eject_device(mon, bs, 0) < 0) {
return -1;
}
bdrv_flags = bdrv_is_read_only(bs) ? 0 : BDRV_O_RDWR;
bdrv_flags |= bdrv_is_snapshot(bs) ? BDRV_O_SNAPSHOT : 0;
if (bdrv_open(bs, filename, bdrv_flags, drv) < 0) {
qerror_report(QERR_OPEN_FILE_FAILED, filename);
return -1;
}
return monitor_read_bdrv_key_start(mon, bs, NULL, NULL);
}
int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
{
const char *id = qdict_get_str(qdict, "id");
BlockDriverState *bs;
bs = bdrv_find(id);
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, id);
return -1;
}
if (bdrv_in_use(bs)) {
qerror_report(QERR_DEVICE_IN_USE, id);
return -1;
}
/* quiesce block driver; prevent further io */
qemu_aio_flush();
bdrv_flush(bs);
bdrv_close(bs);
/* if we have a device associated with this BlockDriverState (bs->peer)
* then we need to make the drive anonymous until the device
* can be removed. If this is a drive with no device backing
* then we can just get rid of the block driver state right here.
*/
if (bs->peer) {
bdrv_make_anon(bs);
} else {
drive_uninit(drive_get_by_blockdev(bs));
}
return 0;
}
/*
* XXX: replace the QERR_UNDEFINED_ERROR errors with real values once the
* existing QERR_ macro mess is cleaned up. A good example for better
* error reports can be found in the qemu-img resize code.
*/
int do_block_resize(Monitor *mon, const QDict *qdict, QObject **ret_data)
{
const char *device = qdict_get_str(qdict, "device");
int64_t size = qdict_get_int(qdict, "size");
BlockDriverState *bs;
bs = bdrv_find(device);
if (!bs) {
qerror_report(QERR_DEVICE_NOT_FOUND, device);
return -1;
}
if (size < 0) {
qerror_report(QERR_UNDEFINED_ERROR);
return -1;
}
if (bdrv_truncate(bs, size)) {
qerror_report(QERR_UNDEFINED_ERROR);
return -1;
}
return 0;
}
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