block.c 150.9 KB
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/*
 * QEMU System Emulator block driver
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 *
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 * Copyright (c) 2003 Fabrice Bellard
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 *
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 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
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#include "config-host.h"
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#include "qemu-common.h"
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#include "trace.h"
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#include "monitor/monitor.h"
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#include "block/block_int.h"
#include "block/blockjob.h"
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#include "qemu/module.h"
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#include "qapi/qmp/qjson.h"
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#include "sysemu/sysemu.h"
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#include "qemu/notify.h"
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#include "block/coroutine.h"
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#include "block/qapi.h"
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#include "qmp-commands.h"
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#include "qemu/timer.h"
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#ifdef CONFIG_BSD
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#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
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#include <sys/queue.h>
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#ifndef __DragonFly__
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#include <sys/disk.h>
#endif
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#endif
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#ifdef _WIN32
#include <windows.h>
#endif

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struct BdrvDirtyBitmap {
    HBitmap *bitmap;
    QLIST_ENTRY(BdrvDirtyBitmap) list;
};

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#define NOT_DONE 0x7fffffff /* used while emulated sync operation in progress */

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static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load);
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static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
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        BlockDriverCompletionFunc *cb, void *opaque);
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static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
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        BlockDriverCompletionFunc *cb, void *opaque);
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static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,
                                         int64_t sector_num, int nb_sectors,
                                         QEMUIOVector *iov);
static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
                                         int64_t sector_num, int nb_sectors,
                                         QEMUIOVector *iov);
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static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
    int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
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    BdrvRequestFlags flags);
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static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
    int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
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    BdrvRequestFlags flags);
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static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
                                               int64_t sector_num,
                                               QEMUIOVector *qiov,
                                               int nb_sectors,
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                                               BdrvRequestFlags flags,
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                                               BlockDriverCompletionFunc *cb,
                                               void *opaque,
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                                               bool is_write);
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static void coroutine_fn bdrv_co_do_rw(void *opaque);
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static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
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    int64_t sector_num, int nb_sectors, BdrvRequestFlags flags);
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static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
    QTAILQ_HEAD_INITIALIZER(bdrv_states);
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static QTAILQ_HEAD(, BlockDriverState) graph_bdrv_states =
    QTAILQ_HEAD_INITIALIZER(graph_bdrv_states);

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static QLIST_HEAD(, BlockDriver) bdrv_drivers =
    QLIST_HEAD_INITIALIZER(bdrv_drivers);
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/* If non-zero, use only whitelisted block drivers */
static int use_bdrv_whitelist;

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#ifdef _WIN32
static int is_windows_drive_prefix(const char *filename)
{
    return (((filename[0] >= 'a' && filename[0] <= 'z') ||
             (filename[0] >= 'A' && filename[0] <= 'Z')) &&
            filename[1] == ':');
}

int is_windows_drive(const char *filename)
{
    if (is_windows_drive_prefix(filename) &&
        filename[2] == '\0')
        return 1;
    if (strstart(filename, "\\\\.\\", NULL) ||
        strstart(filename, "//./", NULL))
        return 1;
    return 0;
}
#endif

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/* throttling disk I/O limits */
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void bdrv_set_io_limits(BlockDriverState *bs,
                        ThrottleConfig *cfg)
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{
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    int i;
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    throttle_config(&bs->throttle_state, cfg);
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    for (i = 0; i < 2; i++) {
        qemu_co_enter_next(&bs->throttled_reqs[i]);
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    }
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}

/* this function drain all the throttled IOs */
static bool bdrv_start_throttled_reqs(BlockDriverState *bs)
{
    bool drained = false;
    bool enabled = bs->io_limits_enabled;
    int i;

    bs->io_limits_enabled = false;

    for (i = 0; i < 2; i++) {
        while (qemu_co_enter_next(&bs->throttled_reqs[i])) {
            drained = true;
        }
    }

    bs->io_limits_enabled = enabled;
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    return drained;
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}

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void bdrv_io_limits_disable(BlockDriverState *bs)
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{
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    bs->io_limits_enabled = false;
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    bdrv_start_throttled_reqs(bs);

    throttle_destroy(&bs->throttle_state);
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}

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static void bdrv_throttle_read_timer_cb(void *opaque)
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{
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    BlockDriverState *bs = opaque;
    qemu_co_enter_next(&bs->throttled_reqs[0]);
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}

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static void bdrv_throttle_write_timer_cb(void *opaque)
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{
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    BlockDriverState *bs = opaque;
    qemu_co_enter_next(&bs->throttled_reqs[1]);
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}

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/* should be called before bdrv_set_io_limits if a limit is set */
void bdrv_io_limits_enable(BlockDriverState *bs)
{
    assert(!bs->io_limits_enabled);
    throttle_init(&bs->throttle_state,
                  QEMU_CLOCK_VIRTUAL,
                  bdrv_throttle_read_timer_cb,
                  bdrv_throttle_write_timer_cb,
                  bs);
    bs->io_limits_enabled = true;
}

/* This function makes an IO wait if needed
 *
 * @nb_sectors: the number of sectors of the IO
 * @is_write:   is the IO a write
 */
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static void bdrv_io_limits_intercept(BlockDriverState *bs,
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                                     unsigned int bytes,
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                                     bool is_write)
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{
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    /* does this io must wait */
    bool must_wait = throttle_schedule_timer(&bs->throttle_state, is_write);
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    /* if must wait or any request of this type throttled queue the IO */
    if (must_wait ||
        !qemu_co_queue_empty(&bs->throttled_reqs[is_write])) {
        qemu_co_queue_wait(&bs->throttled_reqs[is_write]);
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    }

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    /* the IO will be executed, do the accounting */
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    throttle_account(&bs->throttle_state, is_write, bytes);

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    /* if the next request must wait -> do nothing */
    if (throttle_schedule_timer(&bs->throttle_state, is_write)) {
        return;
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    }

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    /* else queue next request for execution */
    qemu_co_queue_next(&bs->throttled_reqs[is_write]);
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}

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size_t bdrv_opt_mem_align(BlockDriverState *bs)
{
    if (!bs || !bs->drv) {
        /* 4k should be on the safe side */
        return 4096;
    }

    return bs->bl.opt_mem_alignment;
}

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/* check if the path starts with "<protocol>:" */
static int path_has_protocol(const char *path)
{
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    const char *p;

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#ifdef _WIN32
    if (is_windows_drive(path) ||
        is_windows_drive_prefix(path)) {
        return 0;
    }
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    p = path + strcspn(path, ":/\\");
#else
    p = path + strcspn(path, ":/");
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#endif

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    return *p == ':';
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}

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int path_is_absolute(const char *path)
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{
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#ifdef _WIN32
    /* specific case for names like: "\\.\d:" */
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    if (is_windows_drive(path) || is_windows_drive_prefix(path)) {
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        return 1;
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    }
    return (*path == '/' || *path == '\\');
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#else
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    return (*path == '/');
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#endif
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}

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/* if filename is absolute, just copy it to dest. Otherwise, build a
   path to it by considering it is relative to base_path. URL are
   supported. */
void path_combine(char *dest, int dest_size,
                  const char *base_path,
                  const char *filename)
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{
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    const char *p, *p1;
    int len;

    if (dest_size <= 0)
        return;
    if (path_is_absolute(filename)) {
        pstrcpy(dest, dest_size, filename);
    } else {
        p = strchr(base_path, ':');
        if (p)
            p++;
        else
            p = base_path;
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        p1 = strrchr(base_path, '/');
#ifdef _WIN32
        {
            const char *p2;
            p2 = strrchr(base_path, '\\');
            if (!p1 || p2 > p1)
                p1 = p2;
        }
#endif
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        if (p1)
            p1++;
        else
            p1 = base_path;
        if (p1 > p)
            p = p1;
        len = p - base_path;
        if (len > dest_size - 1)
            len = dest_size - 1;
        memcpy(dest, base_path, len);
        dest[len] = '\0';
        pstrcat(dest, dest_size, filename);
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    }
}

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void bdrv_get_full_backing_filename(BlockDriverState *bs, char *dest, size_t sz)
{
    if (bs->backing_file[0] == '\0' || path_has_protocol(bs->backing_file)) {
        pstrcpy(dest, sz, bs->backing_file);
    } else {
        path_combine(dest, sz, bs->filename, bs->backing_file);
    }
}

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void bdrv_register(BlockDriver *bdrv)
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{
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    /* Block drivers without coroutine functions need emulation */
    if (!bdrv->bdrv_co_readv) {
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        bdrv->bdrv_co_readv = bdrv_co_readv_em;
        bdrv->bdrv_co_writev = bdrv_co_writev_em;

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        /* bdrv_co_readv_em()/brdv_co_writev_em() work in terms of aio, so if
         * the block driver lacks aio we need to emulate that too.
         */
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        if (!bdrv->bdrv_aio_readv) {
            /* add AIO emulation layer */
            bdrv->bdrv_aio_readv = bdrv_aio_readv_em;
            bdrv->bdrv_aio_writev = bdrv_aio_writev_em;
        }
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    }
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    QLIST_INSERT_HEAD(&bdrv_drivers, bdrv, list);
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}
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/* create a new block device (by default it is empty) */
BlockDriverState *bdrv_new(const char *device_name)
{
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    BlockDriverState *bs;
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    bs = g_malloc0(sizeof(BlockDriverState));
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    QLIST_INIT(&bs->dirty_bitmaps);
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    pstrcpy(bs->device_name, sizeof(bs->device_name), device_name);
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    if (device_name[0] != '\0') {
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        QTAILQ_INSERT_TAIL(&bdrv_states, bs, device_list);
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    }
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    bdrv_iostatus_disable(bs);
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    notifier_list_init(&bs->close_notifiers);
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    notifier_with_return_list_init(&bs->before_write_notifiers);
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    qemu_co_queue_init(&bs->throttled_reqs[0]);
    qemu_co_queue_init(&bs->throttled_reqs[1]);
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    bs->refcnt = 1;
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    return bs;
}

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void bdrv_add_close_notifier(BlockDriverState *bs, Notifier *notify)
{
    notifier_list_add(&bs->close_notifiers, notify);
}

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BlockDriver *bdrv_find_format(const char *format_name)
{
    BlockDriver *drv1;
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    QLIST_FOREACH(drv1, &bdrv_drivers, list) {
        if (!strcmp(drv1->format_name, format_name)) {
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            return drv1;
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        }
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    }
    return NULL;
}

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static int bdrv_is_whitelisted(BlockDriver *drv, bool read_only)
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{
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    static const char *whitelist_rw[] = {
        CONFIG_BDRV_RW_WHITELIST
    };
    static const char *whitelist_ro[] = {
        CONFIG_BDRV_RO_WHITELIST
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    };
    const char **p;

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    if (!whitelist_rw[0] && !whitelist_ro[0]) {
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        return 1;               /* no whitelist, anything goes */
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    }
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    for (p = whitelist_rw; *p; p++) {
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        if (!strcmp(drv->format_name, *p)) {
            return 1;
        }
    }
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    if (read_only) {
        for (p = whitelist_ro; *p; p++) {
            if (!strcmp(drv->format_name, *p)) {
                return 1;
            }
        }
    }
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    return 0;
}

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BlockDriver *bdrv_find_whitelisted_format(const char *format_name,
                                          bool read_only)
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{
    BlockDriver *drv = bdrv_find_format(format_name);
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    return drv && bdrv_is_whitelisted(drv, read_only) ? drv : NULL;
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}

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typedef struct CreateCo {
    BlockDriver *drv;
    char *filename;
    QEMUOptionParameter *options;
    int ret;
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    Error *err;
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} CreateCo;

static void coroutine_fn bdrv_create_co_entry(void *opaque)
{
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    Error *local_err = NULL;
    int ret;

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    CreateCo *cco = opaque;
    assert(cco->drv);

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    ret = cco->drv->bdrv_create(cco->filename, cco->options, &local_err);
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    if (local_err) {
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        error_propagate(&cco->err, local_err);
    }
    cco->ret = ret;
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}

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int bdrv_create(BlockDriver *drv, const char* filename,
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    QEMUOptionParameter *options, Error **errp)
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{
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    int ret;

    Coroutine *co;
    CreateCo cco = {
        .drv = drv,
        .filename = g_strdup(filename),
        .options = options,
        .ret = NOT_DONE,
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        .err = NULL,
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    };

    if (!drv->bdrv_create) {
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        error_setg(errp, "Driver '%s' does not support image creation", drv->format_name);
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        ret = -ENOTSUP;
        goto out;
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    }

    if (qemu_in_coroutine()) {
        /* Fast-path if already in coroutine context */
        bdrv_create_co_entry(&cco);
    } else {
        co = qemu_coroutine_create(bdrv_create_co_entry);
        qemu_coroutine_enter(co, &cco);
        while (cco.ret == NOT_DONE) {
            qemu_aio_wait();
        }
    }

    ret = cco.ret;
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    if (ret < 0) {
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        if (cco.err) {
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            error_propagate(errp, cco.err);
        } else {
            error_setg_errno(errp, -ret, "Could not create image");
        }
    }
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out:
    g_free(cco.filename);
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    return ret;
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}

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int bdrv_create_file(const char* filename, QEMUOptionParameter *options,
                     Error **errp)
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{
    BlockDriver *drv;
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    Error *local_err = NULL;
    int ret;
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    drv = bdrv_find_protocol(filename, true);
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    if (drv == NULL) {
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        error_setg(errp, "Could not find protocol for file '%s'", filename);
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        return -ENOENT;
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    }

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    ret = bdrv_create(drv, filename, options, &local_err);
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    if (local_err) {
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        error_propagate(errp, local_err);
    }
    return ret;
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}

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int bdrv_refresh_limits(BlockDriverState *bs)
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{
    BlockDriver *drv = bs->drv;

    memset(&bs->bl, 0, sizeof(bs->bl));

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    if (!drv) {
        return 0;
    }

    /* Take some limits from the children as a default */
    if (bs->file) {
        bdrv_refresh_limits(bs->file);
        bs->bl.opt_transfer_length = bs->file->bl.opt_transfer_length;
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        bs->bl.opt_mem_alignment = bs->file->bl.opt_mem_alignment;
    } else {
        bs->bl.opt_mem_alignment = 512;
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    }

    if (bs->backing_hd) {
        bdrv_refresh_limits(bs->backing_hd);
        bs->bl.opt_transfer_length =
            MAX(bs->bl.opt_transfer_length,
                bs->backing_hd->bl.opt_transfer_length);
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        bs->bl.opt_mem_alignment =
            MAX(bs->bl.opt_mem_alignment,
                bs->backing_hd->bl.opt_mem_alignment);
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    }

    /* Then let the driver override it */
    if (drv->bdrv_refresh_limits) {
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        return drv->bdrv_refresh_limits(bs);
    }

    return 0;
}

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/*
 * Create a uniquely-named empty temporary file.
 * Return 0 upon success, otherwise a negative errno value.
 */
int get_tmp_filename(char *filename, int size)
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{
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#ifdef _WIN32
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    char temp_dir[MAX_PATH];
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    /* GetTempFileName requires that its output buffer (4th param)
       have length MAX_PATH or greater.  */
    assert(size >= MAX_PATH);
    return (GetTempPath(MAX_PATH, temp_dir)
            && GetTempFileName(temp_dir, "qem", 0, filename)
            ? 0 : -GetLastError());
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#else
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    int fd;
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    const char *tmpdir;
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    tmpdir = getenv("TMPDIR");
    if (!tmpdir)
        tmpdir = "/tmp";
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    if (snprintf(filename, size, "%s/vl.XXXXXX", tmpdir) >= size) {
        return -EOVERFLOW;
    }
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    fd = mkstemp(filename);
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    if (fd < 0) {
        return -errno;
    }
    if (close(fd) != 0) {
        unlink(filename);
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        return -errno;
    }
    return 0;
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#endif
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}
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/*
 * Detect host devices. By convention, /dev/cdrom[N] is always
 * recognized as a host CDROM.
 */
static BlockDriver *find_hdev_driver(const char *filename)
{
    int score_max = 0, score;
    BlockDriver *drv = NULL, *d;

    QLIST_FOREACH(d, &bdrv_drivers, list) {
        if (d->bdrv_probe_device) {
            score = d->bdrv_probe_device(filename);
            if (score > score_max) {
                score_max = score;
                drv = d;
            }
        }
    }

    return drv;
}

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BlockDriver *bdrv_find_protocol(const char *filename,
                                bool allow_protocol_prefix)
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{
    BlockDriver *drv1;
    char protocol[128];
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    int len;
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    const char *p;
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    /* TODO Drivers without bdrv_file_open must be specified explicitly */

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    /*
     * XXX(hch): we really should not let host device detection
     * override an explicit protocol specification, but moving this
     * later breaks access to device names with colons in them.
     * Thanks to the brain-dead persistent naming schemes on udev-
     * based Linux systems those actually are quite common.
     */
    drv1 = find_hdev_driver(filename);
    if (drv1) {
        return drv1;
    }

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    if (!path_has_protocol(filename) || !allow_protocol_prefix) {
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        return bdrv_find_format("file");
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    }
614

615 616
    p = strchr(filename, ':');
    assert(p != NULL);
617 618 619 620 621
    len = p - filename;
    if (len > sizeof(protocol) - 1)
        len = sizeof(protocol) - 1;
    memcpy(protocol, filename, len);
    protocol[len] = '\0';
622
    QLIST_FOREACH(drv1, &bdrv_drivers, list) {
623
        if (drv1->protocol_name &&
624
            !strcmp(drv1->protocol_name, protocol)) {
B
bellard 已提交
625
            return drv1;
626
        }
B
bellard 已提交
627 628 629 630
    }
    return NULL;
}

631
static int find_image_format(BlockDriverState *bs, const char *filename,
632
                             BlockDriver **pdrv, Error **errp)
633
{
634
    int score, score_max;
635 636
    BlockDriver *drv1, *drv;
    uint8_t buf[2048];
637
    int ret = 0;
638

639
    /* Return the raw BlockDriver * to scsi-generic devices or empty drives */
640
    if (bs->sg || !bdrv_is_inserted(bs) || bdrv_getlength(bs) == 0) {
641 642
        drv = bdrv_find_format("raw");
        if (!drv) {
643
            error_setg(errp, "Could not find raw image format");
644 645 646 647
            ret = -ENOENT;
        }
        *pdrv = drv;
        return ret;
648
    }
649

B
bellard 已提交
650 651
    ret = bdrv_pread(bs, 0, buf, sizeof(buf));
    if (ret < 0) {
652 653
        error_setg_errno(errp, -ret, "Could not read image for determining its "
                         "format");
654 655
        *pdrv = NULL;
        return ret;
B
bellard 已提交
656 657
    }

B
bellard 已提交
658
    score_max = 0;
659
    drv = NULL;
660
    QLIST_FOREACH(drv1, &bdrv_drivers, list) {
B
bellard 已提交
661 662 663 664 665 666
        if (drv1->bdrv_probe) {
            score = drv1->bdrv_probe(buf, ret, filename);
            if (score > score_max) {
                score_max = score;
                drv = drv1;
            }
B
bellard 已提交
667
        }
B
bellard 已提交
668
    }
669
    if (!drv) {
670 671
        error_setg(errp, "Could not determine image format: No compatible "
                   "driver found");
672 673 674 675
        ret = -ENOENT;
    }
    *pdrv = drv;
    return ret;
B
bellard 已提交
676 677
}

678 679 680 681 682 683 684
/**
 * Set the current 'total_sectors' value
 */
static int refresh_total_sectors(BlockDriverState *bs, int64_t hint)
{
    BlockDriver *drv = bs->drv;

685 686 687 688
    /* Do not attempt drv->bdrv_getlength() on scsi-generic devices */
    if (bs->sg)
        return 0;

689 690 691 692 693 694
    /* query actual device if possible, otherwise just trust the hint */
    if (drv->bdrv_getlength) {
        int64_t length = drv->bdrv_getlength(bs);
        if (length < 0) {
            return length;
        }
F
Fam Zheng 已提交
695
        hint = DIV_ROUND_UP(length, BDRV_SECTOR_SIZE);
696 697 698 699 700 701
    }

    bs->total_sectors = hint;
    return 0;
}

P
Paolo Bonzini 已提交
702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721
/**
 * Set open flags for a given discard mode
 *
 * Return 0 on success, -1 if the discard mode was invalid.
 */
int bdrv_parse_discard_flags(const char *mode, int *flags)
{
    *flags &= ~BDRV_O_UNMAP;

    if (!strcmp(mode, "off") || !strcmp(mode, "ignore")) {
        /* do nothing */
    } else if (!strcmp(mode, "on") || !strcmp(mode, "unmap")) {
        *flags |= BDRV_O_UNMAP;
    } else {
        return -1;
    }

    return 0;
}

722 723 724 725 726 727 728 729 730 731 732
/**
 * Set open flags for a given cache mode
 *
 * Return 0 on success, -1 if the cache mode was invalid.
 */
int bdrv_parse_cache_flags(const char *mode, int *flags)
{
    *flags &= ~BDRV_O_CACHE_MASK;

    if (!strcmp(mode, "off") || !strcmp(mode, "none")) {
        *flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB;
733 734
    } else if (!strcmp(mode, "directsync")) {
        *flags |= BDRV_O_NOCACHE;
735 736 737 738 739 740 741 742 743 744 745 746 747 748
    } else if (!strcmp(mode, "writeback")) {
        *flags |= BDRV_O_CACHE_WB;
    } else if (!strcmp(mode, "unsafe")) {
        *flags |= BDRV_O_CACHE_WB;
        *flags |= BDRV_O_NO_FLUSH;
    } else if (!strcmp(mode, "writethrough")) {
        /* this is the default */
    } else {
        return -1;
    }

    return 0;
}

749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764
/**
 * The copy-on-read flag is actually a reference count so multiple users may
 * use the feature without worrying about clobbering its previous state.
 * Copy-on-read stays enabled until all users have called to disable it.
 */
void bdrv_enable_copy_on_read(BlockDriverState *bs)
{
    bs->copy_on_read++;
}

void bdrv_disable_copy_on_read(BlockDriverState *bs)
{
    assert(bs->copy_on_read > 0);
    bs->copy_on_read--;
}

K
Kevin Wolf 已提交
765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784
static int bdrv_open_flags(BlockDriverState *bs, int flags)
{
    int open_flags = flags | BDRV_O_CACHE_WB;

    /*
     * Clear flags that are internal to the block layer before opening the
     * image.
     */
    open_flags &= ~(BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);

    /*
     * Snapshots should be writable.
     */
    if (bs->is_temporary) {
        open_flags |= BDRV_O_RDWR;
    }

    return open_flags;
}

785 786 787 788 789 790 791 792 793 794 795 796 797 798
static int bdrv_assign_node_name(BlockDriverState *bs,
                                 const char *node_name,
                                 Error **errp)
{
    if (!node_name) {
        return 0;
    }

    /* empty string node name is invalid */
    if (node_name[0] == '\0') {
        error_setg(errp, "Empty node name");
        return -EINVAL;
    }

799 800 801 802 803 804 805
    /* takes care of avoiding namespaces collisions */
    if (bdrv_find(node_name)) {
        error_setg(errp, "node-name=%s is conflicting with a device id",
                   node_name);
        return -EINVAL;
    }

806 807 808 809 810 811 812 813 814 815 816 817 818
    /* takes care of avoiding duplicates node names */
    if (bdrv_find_node(node_name)) {
        error_setg(errp, "Duplicate node name");
        return -EINVAL;
    }

    /* copy node name into the bs and insert it into the graph list */
    pstrcpy(bs->node_name, sizeof(bs->node_name), node_name);
    QTAILQ_INSERT_TAIL(&graph_bdrv_states, bs, node_list);

    return 0;
}

819 820
/*
 * Common part for opening disk images and files
821 822
 *
 * Removes all processed options from *options.
823
 */
824
static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file,
825
    QDict *options, int flags, BlockDriver *drv, Error **errp)
826 827
{
    int ret, open_flags;
K
Kevin Wolf 已提交
828
    const char *filename;
829
    const char *node_name = NULL;
830
    Error *local_err = NULL;
831 832

    assert(drv != NULL);
833
    assert(bs->file == NULL);
834
    assert(options != NULL && bs->options != options);
835

836 837 838 839 840 841
    if (file != NULL) {
        filename = file->filename;
    } else {
        filename = qdict_get_try_str(options, "filename");
    }

842 843 844 845 846 847
    if (drv->bdrv_needs_filename && !filename) {
        error_setg(errp, "The '%s' block driver requires a file name",
                   drv->format_name);
        return -EINVAL;
    }

848
    trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name);
S
Stefan Hajnoczi 已提交
849

850 851 852 853 854 855 856
    node_name = qdict_get_try_str(options, "node-name");
    ret = bdrv_assign_node_name(bs, node_name, errp);
    if (ret < 0) {
        return ret;
    }
    qdict_del(options, "node-name");

857 858 859 860 861 862 863 864
    /* bdrv_open() with directly using a protocol as drv. This layer is already
     * opened, so assign it to bs (while file becomes a closed BlockDriverState)
     * and return immediately. */
    if (file != NULL && drv->bdrv_file_open) {
        bdrv_swap(file, bs);
        return 0;
    }

865
    bs->open_flags = flags;
866
    bs->guest_block_size = 512;
867
    bs->request_alignment = 512;
A
Asias He 已提交
868
    bs->zero_beyond_eof = true;
869 870 871 872
    open_flags = bdrv_open_flags(bs, flags);
    bs->read_only = !(open_flags & BDRV_O_RDWR);

    if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
873 874 875 876 877
        error_setg(errp,
                   !bs->read_only && bdrv_is_whitelisted(drv, true)
                        ? "Driver '%s' can only be used for read-only devices"
                        : "Driver '%s' is not whitelisted",
                   drv->format_name);
878 879
        return -ENOTSUP;
    }
880

881
    assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */
882 883 884 885 886 887 888
    if (flags & BDRV_O_COPY_ON_READ) {
        if (!bs->read_only) {
            bdrv_enable_copy_on_read(bs);
        } else {
            error_setg(errp, "Can't use copy-on-read on read-only device");
            return -EINVAL;
        }
889 890
    }

891 892 893 894 895
    if (filename != NULL) {
        pstrcpy(bs->filename, sizeof(bs->filename), filename);
    } else {
        bs->filename[0] = '\0';
    }
896 897

    bs->drv = drv;
898
    bs->opaque = g_malloc0(drv->instance_size);
899

900
    bs->enable_write_cache = !!(flags & BDRV_O_CACHE_WB);
901

902 903
    /* Open the image, either directly or using a protocol */
    if (drv->bdrv_file_open) {
904
        assert(file == NULL);
905
        assert(!drv->bdrv_needs_filename || filename != NULL);
906
        ret = drv->bdrv_file_open(bs, options, open_flags, &local_err);
907
    } else {
908
        if (file == NULL) {
909 910
            error_setg(errp, "Can't use '%s' as a block driver for the "
                       "protocol level", drv->format_name);
911 912 913
            ret = -EINVAL;
            goto free_and_fail;
        }
914
        bs->file = file;
915
        ret = drv->bdrv_open(bs, options, open_flags, &local_err);
916 917
    }

918
    if (ret < 0) {
919
        if (local_err) {
920
            error_propagate(errp, local_err);
921 922
        } else if (bs->filename[0]) {
            error_setg_errno(errp, -ret, "Could not open '%s'", bs->filename);
923 924 925
        } else {
            error_setg_errno(errp, -ret, "Could not open image");
        }
926 927 928
        goto free_and_fail;
    }

929 930
    ret = refresh_total_sectors(bs, bs->total_sectors);
    if (ret < 0) {
931
        error_setg_errno(errp, -ret, "Could not refresh total sector count");
932
        goto free_and_fail;
933
    }
934

935
    bdrv_refresh_limits(bs);
936 937
    assert(bdrv_opt_mem_align(bs) != 0);
    assert(bs->request_alignment != 0);
938

939 940
#ifndef _WIN32
    if (bs->is_temporary) {
D
Dunrong Huang 已提交
941 942
        assert(bs->filename[0] != '\0');
        unlink(bs->filename);
943 944 945 946 947
    }
#endif
    return 0;

free_and_fail:
948
    bs->file = NULL;
949
    g_free(bs->opaque);
950 951 952 953 954
    bs->opaque = NULL;
    bs->drv = NULL;
    return ret;
}

K
Kevin Wolf 已提交
955 956
/*
 * Opens a file using a protocol (file, host_device, nbd, ...)
957
 *
958 959 960 961 962 963
 * options is an indirect pointer to a QDict of options to pass to the block
 * drivers, or pointer to NULL for an empty set of options. If this function
 * takes ownership of the QDict reference, it will set *options to NULL;
 * otherwise, it will contain unused/unrecognized options after this function
 * returns. Then, the caller is responsible for freeing it. If it intends to
 * reuse the QDict, QINCREF() should be called beforehand.
K
Kevin Wolf 已提交
964
 */
965
static int bdrv_file_open(BlockDriverState *bs, const char *filename,
966
                          QDict **options, int flags, Error **errp)
B
bellard 已提交
967
{
968
    BlockDriver *drv;
969
    const char *drvname;
970
    bool allow_protocol_prefix = false;
971
    Error *local_err = NULL;
B
bellard 已提交
972 973
    int ret;

K
Kevin Wolf 已提交
974 975
    /* Fetch the file name from the options QDict if necessary */
    if (!filename) {
976 977 978
        filename = qdict_get_try_str(*options, "filename");
    } else if (filename && !qdict_haskey(*options, "filename")) {
        qdict_put(*options, "filename", qstring_from_str(filename));
979
        allow_protocol_prefix = true;
K
Kevin Wolf 已提交
980
    } else {
981 982
        error_setg(errp, "Can't specify 'file' and 'filename' options at the "
                   "same time");
K
Kevin Wolf 已提交
983 984 985 986
        ret = -EINVAL;
        goto fail;
    }

987
    /* Find the right block driver */
988
    drvname = qdict_get_try_str(*options, "driver");
989
    if (drvname) {
990
        drv = bdrv_find_format(drvname);
991 992 993
        if (!drv) {
            error_setg(errp, "Unknown driver '%s'", drvname);
        }
994
        qdict_del(*options, "driver");
995
    } else if (filename) {
996 997
        drv = bdrv_find_protocol(filename, allow_protocol_prefix);
        if (!drv) {
998
            error_setg(errp, "Unknown protocol");
999
        }
1000
    } else {
1001
        error_setg(errp, "Must specify either driver or file");
1002 1003 1004 1005
        drv = NULL;
    }

    if (!drv) {
1006
        /* errp has been set already */
1007 1008 1009 1010 1011 1012
        ret = -ENOENT;
        goto fail;
    }

    /* Parse the filename and open it */
    if (drv->bdrv_parse_filename && filename) {
1013
        drv->bdrv_parse_filename(filename, *options, &local_err);
1014
        if (local_err) {
1015
            error_propagate(errp, local_err);
1016 1017 1018
            ret = -EINVAL;
            goto fail;
        }
1019
        qdict_del(*options, "filename");
1020 1021
    }

M
Max Reitz 已提交
1022
    if (!drv->bdrv_file_open) {
1023 1024
        ret = bdrv_open(&bs, filename, NULL, *options, flags, drv, &local_err);
        *options = NULL;
M
Max Reitz 已提交
1025
    } else {
1026
        ret = bdrv_open_common(bs, NULL, *options, flags, drv, &local_err);
M
Max Reitz 已提交
1027
    }
B
bellard 已提交
1028
    if (ret < 0) {
1029
        error_propagate(errp, local_err);
1030 1031 1032
        goto fail;
    }

1033
    bs->growable = 1;
B
bellard 已提交
1034
    return 0;
1035 1036 1037

fail:
    return ret;
B
bellard 已提交
1038 1039
}

1040 1041 1042 1043 1044 1045 1046 1047
/*
 * Opens the backing file for a BlockDriverState if not yet open
 *
 * options is a QDict of options to pass to the block drivers, or NULL for an
 * empty set of options. The reference to the QDict is transferred to this
 * function (even on failure), so if the caller intends to reuse the dictionary,
 * it needs to use QINCREF() before calling bdrv_file_open.
 */
1048
int bdrv_open_backing_file(BlockDriverState *bs, QDict *options, Error **errp)
P
Paolo Bonzini 已提交
1049 1050 1051 1052
{
    char backing_filename[PATH_MAX];
    int back_flags, ret;
    BlockDriver *back_drv = NULL;
1053
    Error *local_err = NULL;
P
Paolo Bonzini 已提交
1054 1055

    if (bs->backing_hd != NULL) {
1056
        QDECREF(options);
P
Paolo Bonzini 已提交
1057 1058 1059
        return 0;
    }

1060 1061 1062 1063 1064
    /* NULL means an empty set of options */
    if (options == NULL) {
        options = qdict_new();
    }

P
Paolo Bonzini 已提交
1065
    bs->open_flags &= ~BDRV_O_NO_BACKING;
1066 1067 1068
    if (qdict_haskey(options, "file.filename")) {
        backing_filename[0] = '\0';
    } else if (bs->backing_file[0] == '\0' && qdict_size(options) == 0) {
1069
        QDECREF(options);
P
Paolo Bonzini 已提交
1070
        return 0;
F
Fam Zheng 已提交
1071 1072 1073
    } else {
        bdrv_get_full_backing_filename(bs, backing_filename,
                                       sizeof(backing_filename));
P
Paolo Bonzini 已提交
1074 1075 1076 1077 1078 1079 1080
    }

    if (bs->backing_format[0] != '\0') {
        back_drv = bdrv_find_format(bs->backing_format);
    }

    /* backing files always opened read-only */
1081 1082
    back_flags = bs->open_flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT |
                                    BDRV_O_COPY_ON_READ);
P
Paolo Bonzini 已提交
1083

1084 1085
    assert(bs->backing_hd == NULL);
    ret = bdrv_open(&bs->backing_hd,
1086
                    *backing_filename ? backing_filename : NULL, NULL, options,
1087
                    back_flags, back_drv, &local_err);
P
Paolo Bonzini 已提交
1088 1089 1090
    if (ret < 0) {
        bs->backing_hd = NULL;
        bs->open_flags |= BDRV_O_NO_BACKING;
1091 1092 1093
        error_setg(errp, "Could not open backing file: %s",
                   error_get_pretty(local_err));
        error_free(local_err);
P
Paolo Bonzini 已提交
1094 1095
        return ret;
    }
P
Peter Feiner 已提交
1096 1097 1098 1099 1100 1101

    if (bs->backing_hd->file) {
        pstrcpy(bs->backing_file, sizeof(bs->backing_file),
                bs->backing_hd->file->filename);
    }

1102 1103 1104
    /* Recalculate the BlockLimits with the backing file */
    bdrv_refresh_limits(bs);

P
Paolo Bonzini 已提交
1105 1106 1107
    return 0;
}

M
Max Reitz 已提交
1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120
/*
 * Opens a disk image whose options are given as BlockdevRef in another block
 * device's options.
 *
 * If allow_none is true, no image will be opened if filename is false and no
 * BlockdevRef is given. *pbs will remain unchanged and 0 will be returned.
 *
 * bdrev_key specifies the key for the image's BlockdevRef in the options QDict.
 * That QDict has to be flattened; therefore, if the BlockdevRef is a QDict
 * itself, all options starting with "${bdref_key}." are considered part of the
 * BlockdevRef.
 *
 * The BlockdevRef will be removed from the options QDict.
1121 1122
 *
 * To conform with the behavior of bdrv_open(), *pbs has to be NULL.
M
Max Reitz 已提交
1123 1124 1125
 */
int bdrv_open_image(BlockDriverState **pbs, const char *filename,
                    QDict *options, const char *bdref_key, int flags,
1126
                    bool allow_none, Error **errp)
M
Max Reitz 已提交
1127 1128 1129 1130 1131 1132
{
    QDict *image_options;
    int ret;
    char *bdref_key_dot;
    const char *reference;

1133 1134 1135
    assert(pbs);
    assert(*pbs == NULL);

M
Max Reitz 已提交
1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
    bdref_key_dot = g_strdup_printf("%s.", bdref_key);
    qdict_extract_subqdict(options, &image_options, bdref_key_dot);
    g_free(bdref_key_dot);

    reference = qdict_get_try_str(options, bdref_key);
    if (!filename && !reference && !qdict_size(image_options)) {
        if (allow_none) {
            ret = 0;
        } else {
            error_setg(errp, "A block device must be specified for \"%s\"",
                       bdref_key);
            ret = -EINVAL;
        }
        goto done;
    }

1152
    ret = bdrv_open(pbs, filename, reference, image_options, flags, NULL, errp);
M
Max Reitz 已提交
1153 1154 1155 1156 1157 1158

done:
    qdict_del(options, bdref_key);
    return ret;
}

K
Kevin Wolf 已提交
1159 1160
/*
 * Opens a disk image (raw, qcow2, vmdk, ...)
1161 1162 1163 1164 1165
 *
 * options is a QDict of options to pass to the block drivers, or NULL for an
 * empty set of options. The reference to the QDict belongs to the block layer
 * after the call (even on failure), so if the caller intends to reuse the
 * dictionary, it needs to use QINCREF() before calling bdrv_open.
1166 1167 1168
 *
 * If *pbs is NULL, a new BDS will be created with a pointer to it stored there.
 * If it is not NULL, the referenced BDS will be reused.
1169 1170 1171 1172
 *
 * The reference parameter may be used to specify an existing block device which
 * should be opened. If specified, neither options nor a filename may be given,
 * nor can an existing BDS be reused (that is, *pbs has to be NULL).
K
Kevin Wolf 已提交
1173
 */
1174 1175 1176
int bdrv_open(BlockDriverState **pbs, const char *filename,
              const char *reference, QDict *options, int flags,
              BlockDriver *drv, Error **errp)
B
bellard 已提交
1177
{
K
Kevin Wolf 已提交
1178
    int ret;
1179 1180
    /* TODO: extra byte is a hack to ensure MAX_PATH space on Windows. */
    char tmp_filename[PATH_MAX + 1];
1181
    BlockDriverState *file = NULL, *bs;
1182
    const char *drvname;
1183
    Error *local_err = NULL;
B
bellard 已提交
1184

1185 1186
    assert(pbs);

1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211
    if (reference) {
        bool options_non_empty = options ? qdict_size(options) : false;
        QDECREF(options);

        if (*pbs) {
            error_setg(errp, "Cannot reuse an existing BDS when referencing "
                       "another block device");
            return -EINVAL;
        }

        if (filename || options_non_empty) {
            error_setg(errp, "Cannot reference an existing block device with "
                       "additional options or a new filename");
            return -EINVAL;
        }

        bs = bdrv_lookup_bs(reference, reference, errp);
        if (!bs) {
            return -ENODEV;
        }
        bdrv_ref(bs);
        *pbs = bs;
        return 0;
    }

1212 1213 1214 1215 1216 1217
    if (*pbs) {
        bs = *pbs;
    } else {
        bs = bdrv_new("");
    }

1218 1219 1220 1221 1222 1223
    /* NULL means an empty set of options */
    if (options == NULL) {
        options = qdict_new();
    }

    bs->options = options;
1224
    options = qdict_clone_shallow(options);
1225

1226 1227
    if (flags & BDRV_O_PROTOCOL) {
        assert(!drv);
1228
        ret = bdrv_file_open(bs, filename, &options, flags & ~BDRV_O_PROTOCOL,
1229 1230
                             &local_err);
        if (!ret) {
1231
            goto done;
1232 1233 1234 1235 1236 1237 1238
        } else if (bs->drv) {
            goto close_and_fail;
        } else {
            goto fail;
        }
    }

1239
    /* For snapshot=on, create a temporary qcow2 overlay */
B
bellard 已提交
1240
    if (flags & BDRV_O_SNAPSHOT) {
B
bellard 已提交
1241 1242
        BlockDriverState *bs1;
        int64_t total_size;
K
Kevin Wolf 已提交
1243
        BlockDriver *bdrv_qcow2;
1244
        QEMUOptionParameter *create_options;
1245
        QDict *snapshot_options;
1246

B
bellard 已提交
1247 1248
        /* if snapshot, we create a temporary backing file and open it
           instead of opening 'filename' directly */
1249

1250 1251
        /* Get the required size from the image */
        QINCREF(options);
1252
        bs1 = NULL;
1253
        ret = bdrv_open(&bs1, filename, NULL, options, BDRV_O_NO_BACKING,
1254
                        drv, &local_err);
1255
        if (ret < 0) {
1256
            goto fail;
B
bellard 已提交
1257
        }
1258
        total_size = bdrv_getlength(bs1) & BDRV_SECTOR_MASK;
A
aliguori 已提交
1259

F
Fam Zheng 已提交
1260
        bdrv_unref(bs1);
1261

1262
        /* Create the temporary image */
1263 1264
        ret = get_tmp_filename(tmp_filename, sizeof(tmp_filename));
        if (ret < 0) {
1265
            error_setg_errno(errp, -ret, "Could not get temporary filename");
1266
            goto fail;
1267
        }
A
aliguori 已提交
1268

K
Kevin Wolf 已提交
1269
        bdrv_qcow2 = bdrv_find_format("qcow2");
1270 1271
        create_options = parse_option_parameters("", bdrv_qcow2->create_options,
                                                 NULL);
K
Kevin Wolf 已提交
1272

1273
        set_option_parameter_int(create_options, BLOCK_OPT_SIZE, total_size);
K
Kevin Wolf 已提交
1274

1275
        ret = bdrv_create(bdrv_qcow2, tmp_filename, create_options, &local_err);
1276
        free_option_parameters(create_options);
1277
        if (ret < 0) {
1278
            error_setg_errno(errp, -ret, "Could not create temporary overlay "
1279 1280 1281 1282
                             "'%s': %s", tmp_filename,
                             error_get_pretty(local_err));
            error_free(local_err);
            local_err = NULL;
1283
            goto fail;
B
bellard 已提交
1284
        }
K
Kevin Wolf 已提交
1285

1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301
        /* Prepare a new options QDict for the temporary file, where user
         * options refer to the backing file */
        if (filename) {
            qdict_put(options, "file.filename", qstring_from_str(filename));
        }
        if (drv) {
            qdict_put(options, "driver", qstring_from_str(drv->format_name));
        }

        snapshot_options = qdict_new();
        qdict_put(snapshot_options, "backing", options);
        qdict_flatten(snapshot_options);

        bs->options = snapshot_options;
        options = qdict_clone_shallow(bs->options);

B
bellard 已提交
1302
        filename = tmp_filename;
K
Kevin Wolf 已提交
1303
        drv = bdrv_qcow2;
B
bellard 已提交
1304 1305
        bs->is_temporary = 1;
    }
B
bellard 已提交
1306

1307 1308 1309 1310 1311
    /* Open image file without format layer */
    if (flags & BDRV_O_RDWR) {
        flags |= BDRV_O_ALLOW_RDWR;
    }

1312
    assert(file == NULL);
1313
    ret = bdrv_open_image(&file, filename, options, "file",
1314 1315
                          bdrv_open_flags(bs, flags | BDRV_O_UNMAP) |
                          BDRV_O_PROTOCOL, true, &local_err);
1316 1317
    if (ret < 0) {
        goto fail;
1318 1319
    }

K
Kevin Wolf 已提交
1320
    /* Find the right image format driver */
1321 1322
    drvname = qdict_get_try_str(options, "driver");
    if (drvname) {
1323
        drv = bdrv_find_format(drvname);
1324
        qdict_del(options, "driver");
1325 1326 1327 1328 1329
        if (!drv) {
            error_setg(errp, "Invalid driver: '%s'", drvname);
            ret = -EINVAL;
            goto unlink_and_fail;
        }
1330 1331
    }

1332
    if (!drv) {
1333 1334 1335 1336 1337 1338 1339
        if (file) {
            ret = find_image_format(file, filename, &drv, &local_err);
        } else {
            error_setg(errp, "Must specify either driver or file");
            ret = -EINVAL;
            goto unlink_and_fail;
        }
1340
    }
1341

1342 1343
    if (!drv) {
        goto unlink_and_fail;
B
bellard 已提交
1344
    }
K
Kevin Wolf 已提交
1345 1346

    /* Open the image */
1347
    ret = bdrv_open_common(bs, file, options, flags, drv, &local_err);
K
Kevin Wolf 已提交
1348
    if (ret < 0) {
1349 1350 1351
        goto unlink_and_fail;
    }

1352
    if (file && (bs->file != file)) {
F
Fam Zheng 已提交
1353
        bdrv_unref(file);
1354 1355 1356
        file = NULL;
    }

K
Kevin Wolf 已提交
1357
    /* If there is a backing file, use it */
P
Paolo Bonzini 已提交
1358
    if ((flags & BDRV_O_NO_BACKING) == 0) {
1359 1360
        QDict *backing_options;

1361
        qdict_extract_subqdict(options, &backing_options, "backing.");
1362
        ret = bdrv_open_backing_file(bs, backing_options, &local_err);
K
Kevin Wolf 已提交
1363
        if (ret < 0) {
1364
            goto close_and_fail;
K
Kevin Wolf 已提交
1365 1366 1367
        }
    }

1368
done:
1369
    /* Check if any unknown options were used */
1370
    if (options && (qdict_size(options) != 0)) {
1371
        const QDictEntry *entry = qdict_first(options);
1372 1373 1374 1375 1376 1377 1378 1379
        if (flags & BDRV_O_PROTOCOL) {
            error_setg(errp, "Block protocol '%s' doesn't support the option "
                       "'%s'", drv->format_name, entry->key);
        } else {
            error_setg(errp, "Block format '%s' used by device '%s' doesn't "
                       "support the option '%s'", drv->format_name,
                       bs->device_name, entry->key);
        }
1380 1381 1382 1383 1384 1385

        ret = -EINVAL;
        goto close_and_fail;
    }
    QDECREF(options);

K
Kevin Wolf 已提交
1386
    if (!bdrv_key_required(bs)) {
1387
        bdrv_dev_change_media_cb(bs, true);
K
Kevin Wolf 已提交
1388 1389
    }

1390
    *pbs = bs;
K
Kevin Wolf 已提交
1391 1392 1393
    return 0;

unlink_and_fail:
1394
    if (file != NULL) {
F
Fam Zheng 已提交
1395
        bdrv_unref(file);
1396
    }
K
Kevin Wolf 已提交
1397 1398 1399
    if (bs->is_temporary) {
        unlink(filename);
    }
1400 1401
fail:
    QDECREF(bs->options);
1402
    QDECREF(options);
1403
    bs->options = NULL;
1404 1405 1406 1407 1408 1409
    if (!*pbs) {
        /* If *pbs is NULL, a new BDS has been created in this function and
           needs to be freed now. Otherwise, it does not need to be closed,
           since it has not really been opened yet. */
        bdrv_unref(bs);
    }
1410
    if (local_err) {
1411 1412
        error_propagate(errp, local_err);
    }
1413
    return ret;
1414

1415
close_and_fail:
1416 1417 1418 1419 1420 1421
    /* See fail path, but now the BDS has to be always closed */
    if (*pbs) {
        bdrv_close(bs);
    } else {
        bdrv_unref(bs);
    }
1422
    QDECREF(options);
1423
    if (local_err) {
1424 1425
        error_propagate(errp, local_err);
    }
K
Kevin Wolf 已提交
1426 1427 1428
    return ret;
}

1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596
typedef struct BlockReopenQueueEntry {
     bool prepared;
     BDRVReopenState state;
     QSIMPLEQ_ENTRY(BlockReopenQueueEntry) entry;
} BlockReopenQueueEntry;

/*
 * Adds a BlockDriverState to a simple queue for an atomic, transactional
 * reopen of multiple devices.
 *
 * bs_queue can either be an existing BlockReopenQueue that has had QSIMPLE_INIT
 * already performed, or alternatively may be NULL a new BlockReopenQueue will
 * be created and initialized. This newly created BlockReopenQueue should be
 * passed back in for subsequent calls that are intended to be of the same
 * atomic 'set'.
 *
 * bs is the BlockDriverState to add to the reopen queue.
 *
 * flags contains the open flags for the associated bs
 *
 * returns a pointer to bs_queue, which is either the newly allocated
 * bs_queue, or the existing bs_queue being used.
 *
 */
BlockReopenQueue *bdrv_reopen_queue(BlockReopenQueue *bs_queue,
                                    BlockDriverState *bs, int flags)
{
    assert(bs != NULL);

    BlockReopenQueueEntry *bs_entry;
    if (bs_queue == NULL) {
        bs_queue = g_new0(BlockReopenQueue, 1);
        QSIMPLEQ_INIT(bs_queue);
    }

    if (bs->file) {
        bdrv_reopen_queue(bs_queue, bs->file, flags);
    }

    bs_entry = g_new0(BlockReopenQueueEntry, 1);
    QSIMPLEQ_INSERT_TAIL(bs_queue, bs_entry, entry);

    bs_entry->state.bs = bs;
    bs_entry->state.flags = flags;

    return bs_queue;
}

/*
 * Reopen multiple BlockDriverStates atomically & transactionally.
 *
 * The queue passed in (bs_queue) must have been built up previous
 * via bdrv_reopen_queue().
 *
 * Reopens all BDS specified in the queue, with the appropriate
 * flags.  All devices are prepared for reopen, and failure of any
 * device will cause all device changes to be abandonded, and intermediate
 * data cleaned up.
 *
 * If all devices prepare successfully, then the changes are committed
 * to all devices.
 *
 */
int bdrv_reopen_multiple(BlockReopenQueue *bs_queue, Error **errp)
{
    int ret = -1;
    BlockReopenQueueEntry *bs_entry, *next;
    Error *local_err = NULL;

    assert(bs_queue != NULL);

    bdrv_drain_all();

    QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
        if (bdrv_reopen_prepare(&bs_entry->state, bs_queue, &local_err)) {
            error_propagate(errp, local_err);
            goto cleanup;
        }
        bs_entry->prepared = true;
    }

    /* If we reach this point, we have success and just need to apply the
     * changes
     */
    QSIMPLEQ_FOREACH(bs_entry, bs_queue, entry) {
        bdrv_reopen_commit(&bs_entry->state);
    }

    ret = 0;

cleanup:
    QSIMPLEQ_FOREACH_SAFE(bs_entry, bs_queue, entry, next) {
        if (ret && bs_entry->prepared) {
            bdrv_reopen_abort(&bs_entry->state);
        }
        g_free(bs_entry);
    }
    g_free(bs_queue);
    return ret;
}


/* Reopen a single BlockDriverState with the specified flags. */
int bdrv_reopen(BlockDriverState *bs, int bdrv_flags, Error **errp)
{
    int ret = -1;
    Error *local_err = NULL;
    BlockReopenQueue *queue = bdrv_reopen_queue(NULL, bs, bdrv_flags);

    ret = bdrv_reopen_multiple(queue, &local_err);
    if (local_err != NULL) {
        error_propagate(errp, local_err);
    }
    return ret;
}


/*
 * Prepares a BlockDriverState for reopen. All changes are staged in the
 * 'opaque' field of the BDRVReopenState, which is used and allocated by
 * the block driver layer .bdrv_reopen_prepare()
 *
 * bs is the BlockDriverState to reopen
 * flags are the new open flags
 * queue is the reopen queue
 *
 * Returns 0 on success, non-zero on error.  On error errp will be set
 * as well.
 *
 * On failure, bdrv_reopen_abort() will be called to clean up any data.
 * It is the responsibility of the caller to then call the abort() or
 * commit() for any other BDS that have been left in a prepare() state
 *
 */
int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
                        Error **errp)
{
    int ret = -1;
    Error *local_err = NULL;
    BlockDriver *drv;

    assert(reopen_state != NULL);
    assert(reopen_state->bs->drv != NULL);
    drv = reopen_state->bs->drv;

    /* if we are to stay read-only, do not allow permission change
     * to r/w */
    if (!(reopen_state->bs->open_flags & BDRV_O_ALLOW_RDWR) &&
        reopen_state->flags & BDRV_O_RDWR) {
        error_set(errp, QERR_DEVICE_IS_READ_ONLY,
                  reopen_state->bs->device_name);
        goto error;
    }


    ret = bdrv_flush(reopen_state->bs);
    if (ret) {
        error_set(errp, ERROR_CLASS_GENERIC_ERROR, "Error (%s) flushing drive",
                  strerror(-ret));
        goto error;
    }

    if (drv->bdrv_reopen_prepare) {
        ret = drv->bdrv_reopen_prepare(reopen_state, queue, &local_err);
        if (ret) {
            if (local_err != NULL) {
                error_propagate(errp, local_err);
            } else {
1597 1598
                error_setg(errp, "failed while preparing to reopen image '%s'",
                           reopen_state->bs->filename);
1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640
            }
            goto error;
        }
    } else {
        /* It is currently mandatory to have a bdrv_reopen_prepare()
         * handler for each supported drv. */
        error_set(errp, QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
                  drv->format_name, reopen_state->bs->device_name,
                 "reopening of file");
        ret = -1;
        goto error;
    }

    ret = 0;

error:
    return ret;
}

/*
 * Takes the staged changes for the reopen from bdrv_reopen_prepare(), and
 * makes them final by swapping the staging BlockDriverState contents into
 * the active BlockDriverState contents.
 */
void bdrv_reopen_commit(BDRVReopenState *reopen_state)
{
    BlockDriver *drv;

    assert(reopen_state != NULL);
    drv = reopen_state->bs->drv;
    assert(drv != NULL);

    /* If there are any driver level actions to take */
    if (drv->bdrv_reopen_commit) {
        drv->bdrv_reopen_commit(reopen_state);
    }

    /* set BDS specific flags now */
    reopen_state->bs->open_flags         = reopen_state->flags;
    reopen_state->bs->enable_write_cache = !!(reopen_state->flags &
                                              BDRV_O_CACHE_WB);
    reopen_state->bs->read_only = !(reopen_state->flags & BDRV_O_RDWR);
1641 1642

    bdrv_refresh_limits(reopen_state->bs);
1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662
}

/*
 * Abort the reopen, and delete and free the staged changes in
 * reopen_state
 */
void bdrv_reopen_abort(BDRVReopenState *reopen_state)
{
    BlockDriver *drv;

    assert(reopen_state != NULL);
    drv = reopen_state->bs->drv;
    assert(drv != NULL);

    if (drv->bdrv_reopen_abort) {
        drv->bdrv_reopen_abort(reopen_state);
    }
}


B
bellard 已提交
1663 1664
void bdrv_close(BlockDriverState *bs)
{
1665 1666 1667
    if (bs->job) {
        block_job_cancel_sync(bs->job);
    }
1668 1669 1670
    bdrv_drain_all(); /* complete I/O */
    bdrv_flush(bs);
    bdrv_drain_all(); /* in case flush left pending I/O */
P
Paolo Bonzini 已提交
1671
    notifier_list_notify(&bs->close_notifiers, bs);
K
Kevin Wolf 已提交
1672

1673
    if (bs->drv) {
1674
        if (bs->backing_hd) {
F
Fam Zheng 已提交
1675
            bdrv_unref(bs->backing_hd);
1676 1677
            bs->backing_hd = NULL;
        }
B
bellard 已提交
1678
        bs->drv->bdrv_close(bs);
1679
        g_free(bs->opaque);
B
bellard 已提交
1680 1681 1682 1683
#ifdef _WIN32
        if (bs->is_temporary) {
            unlink(bs->filename);
        }
B
bellard 已提交
1684
#endif
B
bellard 已提交
1685 1686
        bs->opaque = NULL;
        bs->drv = NULL;
1687
        bs->copy_on_read = 0;
1688 1689
        bs->backing_file[0] = '\0';
        bs->backing_format[0] = '\0';
1690 1691 1692 1693 1694
        bs->total_sectors = 0;
        bs->encrypted = 0;
        bs->valid_key = 0;
        bs->sg = 0;
        bs->growable = 0;
A
Asias He 已提交
1695
        bs->zero_beyond_eof = false;
1696 1697
        QDECREF(bs->options);
        bs->options = NULL;
B
bellard 已提交
1698

1699
        if (bs->file != NULL) {
F
Fam Zheng 已提交
1700
            bdrv_unref(bs->file);
1701
            bs->file = NULL;
1702
        }
B
bellard 已提交
1703
    }
Z
Zhi Yong Wu 已提交
1704

P
Pavel Hrdina 已提交
1705 1706
    bdrv_dev_change_media_cb(bs, false);

Z
Zhi Yong Wu 已提交
1707 1708 1709 1710
    /*throttling disk I/O limits*/
    if (bs->io_limits_enabled) {
        bdrv_io_limits_disable(bs);
    }
B
bellard 已提交
1711 1712
}

1713 1714 1715 1716
void bdrv_close_all(void)
{
    BlockDriverState *bs;

1717
    QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
1718 1719 1720 1721
        bdrv_close(bs);
    }
}

1722 1723 1724 1725 1726 1727
/* Check if any requests are in-flight (including throttled requests) */
static bool bdrv_requests_pending(BlockDriverState *bs)
{
    if (!QLIST_EMPTY(&bs->tracked_requests)) {
        return true;
    }
1728 1729 1730 1731
    if (!qemu_co_queue_empty(&bs->throttled_reqs[0])) {
        return true;
    }
    if (!qemu_co_queue_empty(&bs->throttled_reqs[1])) {
1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745
        return true;
    }
    if (bs->file && bdrv_requests_pending(bs->file)) {
        return true;
    }
    if (bs->backing_hd && bdrv_requests_pending(bs->backing_hd)) {
        return true;
    }
    return false;
}

static bool bdrv_requests_pending_all(void)
{
    BlockDriverState *bs;
1746
    QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
1747 1748 1749 1750 1751 1752 1753
        if (bdrv_requests_pending(bs)) {
            return true;
        }
    }
    return false;
}

1754 1755 1756 1757 1758
/*
 * Wait for pending requests to complete across all BlockDriverStates
 *
 * This function does not flush data to disk, use bdrv_flush_all() for that
 * after calling this function.
1759 1760 1761 1762 1763 1764
 *
 * Note that completion of an asynchronous I/O operation can trigger any
 * number of other I/O operations on other devices---for example a coroutine
 * can be arbitrarily complex and a constant flow of I/O can come until the
 * coroutine is complete.  Because of this, it is not possible to have a
 * function to drain a single device's I/O queue.
1765 1766 1767
 */
void bdrv_drain_all(void)
{
1768 1769
    /* Always run first iteration so any pending completion BHs run */
    bool busy = true;
1770 1771
    BlockDriverState *bs;

1772
    while (busy) {
1773
        QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
1774
            bdrv_start_throttled_reqs(bs);
1775
        }
1776

1777 1778
        busy = bdrv_requests_pending_all();
        busy |= aio_poll(qemu_get_aio_context(), busy);
1779 1780 1781
    }
}

1782 1783
/* make a BlockDriverState anonymous by removing from bdrv_state and
 * graph_bdrv_state list.
1784 1785 1786 1787
   Also, NULL terminate the device_name to prevent double remove */
void bdrv_make_anon(BlockDriverState *bs)
{
    if (bs->device_name[0] != '\0') {
1788
        QTAILQ_REMOVE(&bdrv_states, bs, device_list);
1789 1790
    }
    bs->device_name[0] = '\0';
1791 1792 1793 1794
    if (bs->node_name[0] != '\0') {
        QTAILQ_REMOVE(&graph_bdrv_states, bs, node_list);
    }
    bs->node_name[0] = '\0';
1795 1796
}

P
Paolo Bonzini 已提交
1797 1798 1799 1800 1801 1802 1803
static void bdrv_rebind(BlockDriverState *bs)
{
    if (bs->drv && bs->drv->bdrv_rebind) {
        bs->drv->bdrv_rebind(bs);
    }
}

1804 1805
static void bdrv_move_feature_fields(BlockDriverState *bs_dest,
                                     BlockDriverState *bs_src)
1806
{
1807 1808
    /* move some fields that need to stay attached to the device */
    bs_dest->open_flags         = bs_src->open_flags;
1809 1810

    /* dev info */
1811 1812 1813
    bs_dest->dev_ops            = bs_src->dev_ops;
    bs_dest->dev_opaque         = bs_src->dev_opaque;
    bs_dest->dev                = bs_src->dev;
1814
    bs_dest->guest_block_size   = bs_src->guest_block_size;
1815
    bs_dest->copy_on_read       = bs_src->copy_on_read;
1816

1817
    bs_dest->enable_write_cache = bs_src->enable_write_cache;
1818

1819 1820 1821 1822 1823 1824
    /* i/o throttled req */
    memcpy(&bs_dest->throttle_state,
           &bs_src->throttle_state,
           sizeof(ThrottleState));
    bs_dest->throttled_reqs[0]  = bs_src->throttled_reqs[0];
    bs_dest->throttled_reqs[1]  = bs_src->throttled_reqs[1];
1825
    bs_dest->io_limits_enabled  = bs_src->io_limits_enabled;
1826 1827

    /* r/w error */
1828 1829
    bs_dest->on_read_error      = bs_src->on_read_error;
    bs_dest->on_write_error     = bs_src->on_write_error;
1830 1831

    /* i/o status */
1832 1833
    bs_dest->iostatus_enabled   = bs_src->iostatus_enabled;
    bs_dest->iostatus           = bs_src->iostatus;
1834

1835
    /* dirty bitmap */
F
Fam Zheng 已提交
1836
    bs_dest->dirty_bitmaps      = bs_src->dirty_bitmaps;
1837

1838 1839 1840
    /* reference count */
    bs_dest->refcnt             = bs_src->refcnt;

1841
    /* job */
1842 1843
    bs_dest->in_use             = bs_src->in_use;
    bs_dest->job                = bs_src->job;
1844

1845
    /* keep the same entry in bdrv_states */
1846 1847
    pstrcpy(bs_dest->device_name, sizeof(bs_dest->device_name),
            bs_src->device_name);
1848 1849 1850 1851 1852 1853
    bs_dest->device_list = bs_src->device_list;

    /* keep the same entry in graph_bdrv_states
     * We do want to swap name but don't want to swap linked list entries
     */
    bs_dest->node_list   = bs_src->node_list;
1854
}
1855

1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870
/*
 * Swap bs contents for two image chains while they are live,
 * while keeping required fields on the BlockDriverState that is
 * actually attached to a device.
 *
 * This will modify the BlockDriverState fields, and swap contents
 * between bs_new and bs_old. Both bs_new and bs_old are modified.
 *
 * bs_new is required to be anonymous.
 *
 * This function does not create any image files.
 */
void bdrv_swap(BlockDriverState *bs_new, BlockDriverState *bs_old)
{
    BlockDriverState tmp;
J
Jeff Cody 已提交
1871

1872 1873
    /* bs_new must be anonymous and shouldn't have anything fancy enabled */
    assert(bs_new->device_name[0] == '\0');
F
Fam Zheng 已提交
1874
    assert(QLIST_EMPTY(&bs_new->dirty_bitmaps));
1875 1876 1877 1878
    assert(bs_new->job == NULL);
    assert(bs_new->dev == NULL);
    assert(bs_new->in_use == 0);
    assert(bs_new->io_limits_enabled == false);
1879
    assert(!throttle_have_timer(&bs_new->throttle_state));
1880

1881 1882 1883
    tmp = *bs_new;
    *bs_new = *bs_old;
    *bs_old = tmp;
1884

1885 1886 1887 1888
    /* there are some fields that should not be swapped, move them back */
    bdrv_move_feature_fields(&tmp, bs_old);
    bdrv_move_feature_fields(bs_old, bs_new);
    bdrv_move_feature_fields(bs_new, &tmp);
1889

1890 1891 1892 1893 1894 1895 1896 1897
    /* bs_new shouldn't be in bdrv_states even after the swap!  */
    assert(bs_new->device_name[0] == '\0');

    /* Check a few fields that should remain attached to the device */
    assert(bs_new->dev == NULL);
    assert(bs_new->job == NULL);
    assert(bs_new->in_use == 0);
    assert(bs_new->io_limits_enabled == false);
1898
    assert(!throttle_have_timer(&bs_new->throttle_state));
P
Paolo Bonzini 已提交
1899 1900

    bdrv_rebind(bs_new);
1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926
    bdrv_rebind(bs_old);
}

/*
 * Add new bs contents at the top of an image chain while the chain is
 * live, while keeping required fields on the top layer.
 *
 * This will modify the BlockDriverState fields, and swap contents
 * between bs_new and bs_top. Both bs_new and bs_top are modified.
 *
 * bs_new is required to be anonymous.
 *
 * This function does not create any image files.
 */
void bdrv_append(BlockDriverState *bs_new, BlockDriverState *bs_top)
{
    bdrv_swap(bs_new, bs_top);

    /* The contents of 'tmp' will become bs_top, as we are
     * swapping bs_new and bs_top contents. */
    bs_top->backing_hd = bs_new;
    bs_top->open_flags &= ~BDRV_O_NO_BACKING;
    pstrcpy(bs_top->backing_file, sizeof(bs_top->backing_file),
            bs_new->filename);
    pstrcpy(bs_top->backing_format, sizeof(bs_top->backing_format),
            bs_new->drv ? bs_new->drv->format_name : "");
1927 1928
}

F
Fam Zheng 已提交
1929
static void bdrv_delete(BlockDriverState *bs)
B
bellard 已提交
1930
{
1931
    assert(!bs->dev);
1932 1933
    assert(!bs->job);
    assert(!bs->in_use);
F
Fam Zheng 已提交
1934
    assert(!bs->refcnt);
F
Fam Zheng 已提交
1935
    assert(QLIST_EMPTY(&bs->dirty_bitmaps));
1936

1937 1938
    bdrv_close(bs);

1939
    /* remove from list, if necessary */
1940
    bdrv_make_anon(bs);
1941

1942
    g_free(bs);
B
bellard 已提交
1943 1944
}

1945 1946
int bdrv_attach_dev(BlockDriverState *bs, void *dev)
/* TODO change to DeviceState *dev when all users are qdevified */
1947
{
1948
    if (bs->dev) {
1949 1950
        return -EBUSY;
    }
1951
    bs->dev = dev;
1952
    bdrv_iostatus_reset(bs);
1953 1954 1955
    return 0;
}

1956 1957
/* TODO qdevified devices don't use this, remove when devices are qdevified */
void bdrv_attach_dev_nofail(BlockDriverState *bs, void *dev)
1958
{
1959 1960 1961 1962 1963 1964 1965 1966 1967 1968
    if (bdrv_attach_dev(bs, dev) < 0) {
        abort();
    }
}

void bdrv_detach_dev(BlockDriverState *bs, void *dev)
/* TODO change to DeviceState *dev when all users are qdevified */
{
    assert(bs->dev == dev);
    bs->dev = NULL;
1969 1970
    bs->dev_ops = NULL;
    bs->dev_opaque = NULL;
1971
    bs->guest_block_size = 512;
1972 1973
}

1974 1975
/* TODO change to return DeviceState * when all users are qdevified */
void *bdrv_get_attached_dev(BlockDriverState *bs)
1976
{
1977
    return bs->dev;
1978 1979
}

1980 1981 1982 1983 1984 1985 1986
void bdrv_set_dev_ops(BlockDriverState *bs, const BlockDevOps *ops,
                      void *opaque)
{
    bs->dev_ops = ops;
    bs->dev_opaque = opaque;
}

P
Paolo Bonzini 已提交
1987 1988 1989
void bdrv_emit_qmp_error_event(const BlockDriverState *bdrv,
                               enum MonitorEvent ev,
                               BlockErrorAction action, bool is_read)
1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
{
    QObject *data;
    const char *action_str;

    switch (action) {
    case BDRV_ACTION_REPORT:
        action_str = "report";
        break;
    case BDRV_ACTION_IGNORE:
        action_str = "ignore";
        break;
    case BDRV_ACTION_STOP:
        action_str = "stop";
        break;
    default:
        abort();
    }

    data = qobject_from_jsonf("{ 'device': %s, 'action': %s, 'operation': %s }",
                              bdrv->device_name,
                              action_str,
                              is_read ? "read" : "write");
P
Paolo Bonzini 已提交
2012
    monitor_protocol_event(ev, data);
2013 2014 2015 2016

    qobject_decref(data);
}

2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027
static void bdrv_emit_qmp_eject_event(BlockDriverState *bs, bool ejected)
{
    QObject *data;

    data = qobject_from_jsonf("{ 'device': %s, 'tray-open': %i }",
                              bdrv_get_device_name(bs), ejected);
    monitor_protocol_event(QEVENT_DEVICE_TRAY_MOVED, data);

    qobject_decref(data);
}

2028
static void bdrv_dev_change_media_cb(BlockDriverState *bs, bool load)
2029
{
2030
    if (bs->dev_ops && bs->dev_ops->change_media_cb) {
2031
        bool tray_was_closed = !bdrv_dev_is_tray_open(bs);
2032
        bs->dev_ops->change_media_cb(bs->dev_opaque, load);
2033 2034 2035 2036 2037 2038 2039 2040
        if (tray_was_closed) {
            /* tray open */
            bdrv_emit_qmp_eject_event(bs, true);
        }
        if (load) {
            /* tray close */
            bdrv_emit_qmp_eject_event(bs, false);
        }
2041 2042 2043
    }
}

2044 2045 2046 2047 2048
bool bdrv_dev_has_removable_media(BlockDriverState *bs)
{
    return !bs->dev || (bs->dev_ops && bs->dev_ops->change_media_cb);
}

P
Paolo Bonzini 已提交
2049 2050 2051 2052 2053 2054 2055
void bdrv_dev_eject_request(BlockDriverState *bs, bool force)
{
    if (bs->dev_ops && bs->dev_ops->eject_request_cb) {
        bs->dev_ops->eject_request_cb(bs->dev_opaque, force);
    }
}

2056 2057 2058 2059 2060 2061 2062 2063
bool bdrv_dev_is_tray_open(BlockDriverState *bs)
{
    if (bs->dev_ops && bs->dev_ops->is_tray_open) {
        return bs->dev_ops->is_tray_open(bs->dev_opaque);
    }
    return false;
}

2064 2065 2066 2067
static void bdrv_dev_resize_cb(BlockDriverState *bs)
{
    if (bs->dev_ops && bs->dev_ops->resize_cb) {
        bs->dev_ops->resize_cb(bs->dev_opaque);
2068 2069 2070
    }
}

2071 2072 2073 2074 2075 2076 2077 2078
bool bdrv_dev_is_medium_locked(BlockDriverState *bs)
{
    if (bs->dev_ops && bs->dev_ops->is_medium_locked) {
        return bs->dev_ops->is_medium_locked(bs->dev_opaque);
    }
    return false;
}

A
aliguori 已提交
2079 2080 2081
/*
 * Run consistency checks on an image
 *
2082
 * Returns 0 if the check could be completed (it doesn't mean that the image is
2083
 * free of errors) or -errno when an internal error occurred. The results of the
2084
 * check are stored in res.
A
aliguori 已提交
2085
 */
2086
int bdrv_check(BlockDriverState *bs, BdrvCheckResult *res, BdrvCheckMode fix)
A
aliguori 已提交
2087 2088 2089 2090 2091
{
    if (bs->drv->bdrv_check == NULL) {
        return -ENOTSUP;
    }

2092
    memset(res, 0, sizeof(*res));
2093
    return bs->drv->bdrv_check(bs, res, fix);
A
aliguori 已提交
2094 2095
}

2096 2097
#define COMMIT_BUF_SECTORS 2048

2098 2099 2100
/* commit COW file into the raw image */
int bdrv_commit(BlockDriverState *bs)
{
B
bellard 已提交
2101
    BlockDriver *drv = bs->drv;
2102
    int64_t sector, total_sectors, length, backing_length;
2103
    int n, ro, open_flags;
2104
    int ret = 0;
2105
    uint8_t *buf = NULL;
2106
    char filename[PATH_MAX];
2107

B
bellard 已提交
2108 2109
    if (!drv)
        return -ENOMEDIUM;
2110 2111 2112
    
    if (!bs->backing_hd) {
        return -ENOTSUP;
2113 2114
    }

2115 2116 2117 2118
    if (bdrv_in_use(bs) || bdrv_in_use(bs->backing_hd)) {
        return -EBUSY;
    }

2119
    ro = bs->backing_hd->read_only;
2120 2121
    /* Use pstrcpy (not strncpy): filename must be NUL-terminated. */
    pstrcpy(filename, sizeof(filename), bs->backing_hd->filename);
2122 2123 2124
    open_flags =  bs->backing_hd->open_flags;

    if (ro) {
2125 2126
        if (bdrv_reopen(bs->backing_hd, open_flags | BDRV_O_RDWR, NULL)) {
            return -EACCES;
2127
        }
B
bellard 已提交
2128
    }
2129

2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152
    length = bdrv_getlength(bs);
    if (length < 0) {
        ret = length;
        goto ro_cleanup;
    }

    backing_length = bdrv_getlength(bs->backing_hd);
    if (backing_length < 0) {
        ret = backing_length;
        goto ro_cleanup;
    }

    /* If our top snapshot is larger than the backing file image,
     * grow the backing file image if possible.  If not possible,
     * we must return an error */
    if (length > backing_length) {
        ret = bdrv_truncate(bs->backing_hd, length);
        if (ret < 0) {
            goto ro_cleanup;
        }
    }

    total_sectors = length >> BDRV_SECTOR_BITS;
2153
    buf = g_malloc(COMMIT_BUF_SECTORS * BDRV_SECTOR_SIZE);
2154 2155

    for (sector = 0; sector < total_sectors; sector += n) {
2156 2157 2158 2159 2160
        ret = bdrv_is_allocated(bs, sector, COMMIT_BUF_SECTORS, &n);
        if (ret < 0) {
            goto ro_cleanup;
        }
        if (ret) {
K
Kevin Wolf 已提交
2161 2162
            ret = bdrv_read(bs, sector, buf, n);
            if (ret < 0) {
2163 2164 2165
                goto ro_cleanup;
            }

K
Kevin Wolf 已提交
2166 2167
            ret = bdrv_write(bs->backing_hd, sector, buf, n);
            if (ret < 0) {
2168 2169
                goto ro_cleanup;
            }
B
bellard 已提交
2170
        }
2171
    }
2172

2173 2174
    if (drv->bdrv_make_empty) {
        ret = drv->bdrv_make_empty(bs);
K
Kevin Wolf 已提交
2175 2176 2177
        if (ret < 0) {
            goto ro_cleanup;
        }
2178 2179
        bdrv_flush(bs);
    }
2180

2181 2182 2183 2184
    /*
     * Make sure all data we wrote to the backing device is actually
     * stable on disk.
     */
K
Kevin Wolf 已提交
2185
    if (bs->backing_hd) {
2186
        bdrv_flush(bs->backing_hd);
K
Kevin Wolf 已提交
2187
    }
2188

K
Kevin Wolf 已提交
2189
    ret = 0;
2190
ro_cleanup:
2191
    g_free(buf);
2192 2193

    if (ro) {
2194 2195
        /* ignoring error return here */
        bdrv_reopen(bs->backing_hd, open_flags & ~BDRV_O_RDWR, NULL);
2196 2197
    }

2198
    return ret;
2199 2200
}

2201
int bdrv_commit_all(void)
2202 2203 2204
{
    BlockDriverState *bs;

2205
    QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
2206 2207 2208 2209 2210
        if (bs->drv && bs->backing_hd) {
            int ret = bdrv_commit(bs);
            if (ret < 0) {
                return ret;
            }
2211
        }
2212
    }
2213
    return 0;
2214 2215
}

S
Stefan Hajnoczi 已提交
2216 2217 2218 2219 2220 2221 2222
/**
 * Remove an active request from the tracked requests list
 *
 * This function should be called when a tracked request is completing.
 */
static void tracked_request_end(BdrvTrackedRequest *req)
{
2223 2224 2225 2226
    if (req->serialising) {
        req->bs->serialising_in_flight--;
    }

S
Stefan Hajnoczi 已提交
2227
    QLIST_REMOVE(req, list);
2228
    qemu_co_queue_restart_all(&req->wait_queue);
S
Stefan Hajnoczi 已提交
2229 2230 2231 2232 2233 2234 2235
}

/**
 * Add an active request to the tracked requests list
 */
static void tracked_request_begin(BdrvTrackedRequest *req,
                                  BlockDriverState *bs,
2236 2237
                                  int64_t offset,
                                  unsigned int bytes, bool is_write)
S
Stefan Hajnoczi 已提交
2238 2239 2240
{
    *req = (BdrvTrackedRequest){
        .bs = bs,
2241 2242 2243 2244 2245
        .offset         = offset,
        .bytes          = bytes,
        .is_write       = is_write,
        .co             = qemu_coroutine_self(),
        .serialising    = false,
2246 2247
        .overlap_offset = offset,
        .overlap_bytes  = bytes,
S
Stefan Hajnoczi 已提交
2248 2249
    };

2250 2251
    qemu_co_queue_init(&req->wait_queue);

S
Stefan Hajnoczi 已提交
2252 2253 2254
    QLIST_INSERT_HEAD(&bs->tracked_requests, req, list);
}

2255
static void mark_request_serialising(BdrvTrackedRequest *req, uint64_t align)
2256
{
2257
    int64_t overlap_offset = req->offset & ~(align - 1);
2258 2259
    unsigned int overlap_bytes = ROUND_UP(req->offset + req->bytes, align)
                               - overlap_offset;
2260

2261 2262 2263 2264
    if (!req->serialising) {
        req->bs->serialising_in_flight++;
        req->serialising = true;
    }
2265 2266 2267

    req->overlap_offset = MIN(req->overlap_offset, overlap_offset);
    req->overlap_bytes = MAX(req->overlap_bytes, overlap_bytes);
2268 2269
}

S
Stefan Hajnoczi 已提交
2270 2271 2272
/**
 * Round a region to cluster boundaries
 */
2273 2274 2275 2276
void bdrv_round_to_clusters(BlockDriverState *bs,
                            int64_t sector_num, int nb_sectors,
                            int64_t *cluster_sector_num,
                            int *cluster_nb_sectors)
S
Stefan Hajnoczi 已提交
2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290
{
    BlockDriverInfo bdi;

    if (bdrv_get_info(bs, &bdi) < 0 || bdi.cluster_size == 0) {
        *cluster_sector_num = sector_num;
        *cluster_nb_sectors = nb_sectors;
    } else {
        int64_t c = bdi.cluster_size / BDRV_SECTOR_SIZE;
        *cluster_sector_num = QEMU_ALIGN_DOWN(sector_num, c);
        *cluster_nb_sectors = QEMU_ALIGN_UP(sector_num - *cluster_sector_num +
                                            nb_sectors, c);
    }
}

2291
static int bdrv_get_cluster_size(BlockDriverState *bs)
2292 2293
{
    BlockDriverInfo bdi;
2294
    int ret;
2295

2296 2297 2298
    ret = bdrv_get_info(bs, &bdi);
    if (ret < 0 || bdi.cluster_size == 0) {
        return bs->request_alignment;
2299
    } else {
2300
        return bdi.cluster_size;
2301 2302 2303
    }
}

2304
static bool tracked_request_overlaps(BdrvTrackedRequest *req,
2305 2306
                                     int64_t offset, unsigned int bytes)
{
S
Stefan Hajnoczi 已提交
2307
    /*        aaaa   bbbb */
2308
    if (offset >= req->overlap_offset + req->overlap_bytes) {
S
Stefan Hajnoczi 已提交
2309 2310 2311
        return false;
    }
    /* bbbb   aaaa        */
2312
    if (req->overlap_offset >= offset + bytes) {
S
Stefan Hajnoczi 已提交
2313 2314 2315
        return false;
    }
    return true;
2316 2317
}

2318
static bool coroutine_fn wait_serialising_requests(BdrvTrackedRequest *self)
2319
{
2320
    BlockDriverState *bs = self->bs;
2321 2322
    BdrvTrackedRequest *req;
    bool retry;
2323
    bool waited = false;
2324

2325
    if (!bs->serialising_in_flight) {
2326
        return false;
2327 2328
    }

2329 2330 2331
    do {
        retry = false;
        QLIST_FOREACH(req, &bs->tracked_requests, list) {
2332
            if (req == self || (!req->serialising && !self->serialising)) {
2333 2334
                continue;
            }
2335 2336 2337
            if (tracked_request_overlaps(req, self->overlap_offset,
                                         self->overlap_bytes))
            {
2338 2339 2340 2341 2342 2343
                /* Hitting this means there was a reentrant request, for
                 * example, a block driver issuing nested requests.  This must
                 * never happen since it means deadlock.
                 */
                assert(qemu_coroutine_self() != req->co);

2344 2345 2346 2347 2348 2349 2350 2351
                /* If the request is already (indirectly) waiting for us, or
                 * will wait for us as soon as it wakes up, then just go on
                 * (instead of producing a deadlock in the former case). */
                if (!req->waiting_for) {
                    self->waiting_for = req;
                    qemu_co_queue_wait(&req->wait_queue);
                    self->waiting_for = NULL;
                    retry = true;
2352
                    waited = true;
2353 2354
                    break;
                }
2355 2356 2357
            }
        }
    } while (retry);
2358 2359

    return waited;
2360 2361
}

K
Kevin Wolf 已提交
2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373
/*
 * Return values:
 * 0        - success
 * -EINVAL  - backing format specified, but no file
 * -ENOSPC  - can't update the backing file because no space is left in the
 *            image file header
 * -ENOTSUP - format driver doesn't support changing the backing file
 */
int bdrv_change_backing_file(BlockDriverState *bs,
    const char *backing_file, const char *backing_fmt)
{
    BlockDriver *drv = bs->drv;
2374
    int ret;
K
Kevin Wolf 已提交
2375

2376 2377 2378 2379 2380
    /* Backing file format doesn't make sense without a backing file */
    if (backing_fmt && !backing_file) {
        return -EINVAL;
    }

K
Kevin Wolf 已提交
2381
    if (drv->bdrv_change_backing_file != NULL) {
2382
        ret = drv->bdrv_change_backing_file(bs, backing_file, backing_fmt);
K
Kevin Wolf 已提交
2383
    } else {
2384
        ret = -ENOTSUP;
K
Kevin Wolf 已提交
2385
    }
2386 2387 2388 2389 2390 2391

    if (ret == 0) {
        pstrcpy(bs->backing_file, sizeof(bs->backing_file), backing_file ?: "");
        pstrcpy(bs->backing_format, sizeof(bs->backing_format), backing_fmt ?: "");
    }
    return ret;
K
Kevin Wolf 已提交
2392 2393
}

2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520
/*
 * Finds the image layer in the chain that has 'bs' as its backing file.
 *
 * active is the current topmost image.
 *
 * Returns NULL if bs is not found in active's image chain,
 * or if active == bs.
 */
BlockDriverState *bdrv_find_overlay(BlockDriverState *active,
                                    BlockDriverState *bs)
{
    BlockDriverState *overlay = NULL;
    BlockDriverState *intermediate;

    assert(active != NULL);
    assert(bs != NULL);

    /* if bs is the same as active, then by definition it has no overlay
     */
    if (active == bs) {
        return NULL;
    }

    intermediate = active;
    while (intermediate->backing_hd) {
        if (intermediate->backing_hd == bs) {
            overlay = intermediate;
            break;
        }
        intermediate = intermediate->backing_hd;
    }

    return overlay;
}

typedef struct BlkIntermediateStates {
    BlockDriverState *bs;
    QSIMPLEQ_ENTRY(BlkIntermediateStates) entry;
} BlkIntermediateStates;


/*
 * Drops images above 'base' up to and including 'top', and sets the image
 * above 'top' to have base as its backing file.
 *
 * Requires that the overlay to 'top' is opened r/w, so that the backing file
 * information in 'bs' can be properly updated.
 *
 * E.g., this will convert the following chain:
 * bottom <- base <- intermediate <- top <- active
 *
 * to
 *
 * bottom <- base <- active
 *
 * It is allowed for bottom==base, in which case it converts:
 *
 * base <- intermediate <- top <- active
 *
 * to
 *
 * base <- active
 *
 * Error conditions:
 *  if active == top, that is considered an error
 *
 */
int bdrv_drop_intermediate(BlockDriverState *active, BlockDriverState *top,
                           BlockDriverState *base)
{
    BlockDriverState *intermediate;
    BlockDriverState *base_bs = NULL;
    BlockDriverState *new_top_bs = NULL;
    BlkIntermediateStates *intermediate_state, *next;
    int ret = -EIO;

    QSIMPLEQ_HEAD(states_to_delete, BlkIntermediateStates) states_to_delete;
    QSIMPLEQ_INIT(&states_to_delete);

    if (!top->drv || !base->drv) {
        goto exit;
    }

    new_top_bs = bdrv_find_overlay(active, top);

    if (new_top_bs == NULL) {
        /* we could not find the image above 'top', this is an error */
        goto exit;
    }

    /* special case of new_top_bs->backing_hd already pointing to base - nothing
     * to do, no intermediate images */
    if (new_top_bs->backing_hd == base) {
        ret = 0;
        goto exit;
    }

    intermediate = top;

    /* now we will go down through the list, and add each BDS we find
     * into our deletion queue, until we hit the 'base'
     */
    while (intermediate) {
        intermediate_state = g_malloc0(sizeof(BlkIntermediateStates));
        intermediate_state->bs = intermediate;
        QSIMPLEQ_INSERT_TAIL(&states_to_delete, intermediate_state, entry);

        if (intermediate->backing_hd == base) {
            base_bs = intermediate->backing_hd;
            break;
        }
        intermediate = intermediate->backing_hd;
    }
    if (base_bs == NULL) {
        /* something went wrong, we did not end at the base. safely
         * unravel everything, and exit with error */
        goto exit;
    }

    /* success - we can delete the intermediate states, and link top->base */
    ret = bdrv_change_backing_file(new_top_bs, base_bs->filename,
                                   base_bs->drv ? base_bs->drv->format_name : "");
    if (ret) {
        goto exit;
    }
    new_top_bs->backing_hd = base_bs;

2521
    bdrv_refresh_limits(new_top_bs);
2522 2523 2524 2525

    QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) {
        /* so that bdrv_close() does not recursively close the chain */
        intermediate_state->bs->backing_hd = NULL;
F
Fam Zheng 已提交
2526
        bdrv_unref(intermediate_state->bs);
2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537
    }
    ret = 0;

exit:
    QSIMPLEQ_FOREACH_SAFE(intermediate_state, &states_to_delete, entry, next) {
        g_free(intermediate_state);
    }
    return ret;
}


2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550
static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
                                   size_t size)
{
    int64_t len;

    if (!bdrv_is_inserted(bs))
        return -ENOMEDIUM;

    if (bs->growable)
        return 0;

    len = bdrv_getlength(bs);

K
Kevin Wolf 已提交
2551 2552 2553 2554
    if (offset < 0)
        return -EIO;

    if ((offset > len) || (len - offset < size))
2555 2556 2557 2558 2559 2560 2561 2562
        return -EIO;

    return 0;
}

static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
                              int nb_sectors)
{
2563 2564
    return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE,
                                   nb_sectors * BDRV_SECTOR_SIZE);
2565 2566
}

2567 2568
typedef struct RwCo {
    BlockDriverState *bs;
2569
    int64_t offset;
2570 2571 2572
    QEMUIOVector *qiov;
    bool is_write;
    int ret;
P
Peter Lieven 已提交
2573
    BdrvRequestFlags flags;
2574 2575 2576
} RwCo;

static void coroutine_fn bdrv_rw_co_entry(void *opaque)
B
bellard 已提交
2577
{
2578
    RwCo *rwco = opaque;
B
bellard 已提交
2579

2580
    if (!rwco->is_write) {
2581 2582
        rwco->ret = bdrv_co_do_preadv(rwco->bs, rwco->offset,
                                      rwco->qiov->size, rwco->qiov,
P
Peter Lieven 已提交
2583
                                      rwco->flags);
2584 2585 2586 2587
    } else {
        rwco->ret = bdrv_co_do_pwritev(rwco->bs, rwco->offset,
                                       rwco->qiov->size, rwco->qiov,
                                       rwco->flags);
2588 2589
    }
}
2590

2591
/*
2592
 * Process a vectored synchronous request using coroutines
2593
 */
2594 2595 2596
static int bdrv_prwv_co(BlockDriverState *bs, int64_t offset,
                        QEMUIOVector *qiov, bool is_write,
                        BdrvRequestFlags flags)
2597 2598 2599 2600
{
    Coroutine *co;
    RwCo rwco = {
        .bs = bs,
2601
        .offset = offset,
2602
        .qiov = qiov,
2603 2604
        .is_write = is_write,
        .ret = NOT_DONE,
P
Peter Lieven 已提交
2605
        .flags = flags,
2606
    };
2607

2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618
    /**
     * In sync call context, when the vcpu is blocked, this throttling timer
     * will not fire; so the I/O throttling function has to be disabled here
     * if it has been enabled.
     */
    if (bs->io_limits_enabled) {
        fprintf(stderr, "Disabling I/O throttling on '%s' due "
                        "to synchronous I/O.\n", bdrv_get_device_name(bs));
        bdrv_io_limits_disable(bs);
    }

2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630
    if (qemu_in_coroutine()) {
        /* Fast-path if already in coroutine context */
        bdrv_rw_co_entry(&rwco);
    } else {
        co = qemu_coroutine_create(bdrv_rw_co_entry);
        qemu_coroutine_enter(co, &rwco);
        while (rwco.ret == NOT_DONE) {
            qemu_aio_wait();
        }
    }
    return rwco.ret;
}
B
bellard 已提交
2631

2632 2633 2634 2635
/*
 * Process a synchronous request using coroutines
 */
static int bdrv_rw_co(BlockDriverState *bs, int64_t sector_num, uint8_t *buf,
P
Peter Lieven 已提交
2636
                      int nb_sectors, bool is_write, BdrvRequestFlags flags)
2637 2638 2639 2640 2641 2642 2643 2644
{
    QEMUIOVector qiov;
    struct iovec iov = {
        .iov_base = (void *)buf,
        .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
    };

    qemu_iovec_init_external(&qiov, &iov, 1);
2645 2646
    return bdrv_prwv_co(bs, sector_num << BDRV_SECTOR_BITS,
                        &qiov, is_write, flags);
2647 2648
}

2649 2650 2651 2652
/* return < 0 if error. See bdrv_write() for the return codes */
int bdrv_read(BlockDriverState *bs, int64_t sector_num,
              uint8_t *buf, int nb_sectors)
{
P
Peter Lieven 已提交
2653
    return bdrv_rw_co(bs, sector_num, buf, nb_sectors, false, 0);
B
bellard 已提交
2654 2655
}

2656 2657 2658 2659 2660 2661 2662 2663 2664
/* Just like bdrv_read(), but with I/O throttling temporarily disabled */
int bdrv_read_unthrottled(BlockDriverState *bs, int64_t sector_num,
                          uint8_t *buf, int nb_sectors)
{
    bool enabled;
    int ret;

    enabled = bs->io_limits_enabled;
    bs->io_limits_enabled = false;
2665
    ret = bdrv_read(bs, sector_num, buf, nb_sectors);
2666 2667 2668 2669
    bs->io_limits_enabled = enabled;
    return ret;
}

2670
/* Return < 0 if error. Important errors are:
B
bellard 已提交
2671 2672 2673 2674 2675
  -EIO         generic I/O error (may happen for all errors)
  -ENOMEDIUM   No media inserted.
  -EINVAL      Invalid sector number or nb_sectors
  -EACCES      Trying to write a read-only device
*/
2676
int bdrv_write(BlockDriverState *bs, int64_t sector_num,
B
bellard 已提交
2677 2678
               const uint8_t *buf, int nb_sectors)
{
P
Peter Lieven 已提交
2679
    return bdrv_rw_co(bs, sector_num, (uint8_t *)buf, nb_sectors, true, 0);
B
bellard 已提交
2680 2681
}

2682 2683
int bdrv_write_zeroes(BlockDriverState *bs, int64_t sector_num,
                      int nb_sectors, BdrvRequestFlags flags)
P
Peter Lieven 已提交
2684 2685
{
    return bdrv_rw_co(bs, sector_num, NULL, nb_sectors, true,
2686
                      BDRV_REQ_ZERO_WRITE | flags);
2687 2688
}

P
Peter Lieven 已提交
2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711
/*
 * Completely zero out a block device with the help of bdrv_write_zeroes.
 * The operation is sped up by checking the block status and only writing
 * zeroes to the device if they currently do not return zeroes. Optional
 * flags are passed through to bdrv_write_zeroes (e.g. BDRV_REQ_MAY_UNMAP).
 *
 * Returns < 0 on error, 0 on success. For error codes see bdrv_write().
 */
int bdrv_make_zero(BlockDriverState *bs, BdrvRequestFlags flags)
{
    int64_t target_size = bdrv_getlength(bs) / BDRV_SECTOR_SIZE;
    int64_t ret, nb_sectors, sector_num = 0;
    int n;

    for (;;) {
        nb_sectors = target_size - sector_num;
        if (nb_sectors <= 0) {
            return 0;
        }
        if (nb_sectors > INT_MAX) {
            nb_sectors = INT_MAX;
        }
        ret = bdrv_get_block_status(bs, sector_num, nb_sectors, &n);
2712 2713 2714 2715 2716
        if (ret < 0) {
            error_report("error getting block status at sector %" PRId64 ": %s",
                         sector_num, strerror(-ret));
            return ret;
        }
P
Peter Lieven 已提交
2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730
        if (ret & BDRV_BLOCK_ZERO) {
            sector_num += n;
            continue;
        }
        ret = bdrv_write_zeroes(bs, sector_num, n, flags);
        if (ret < 0) {
            error_report("error writing zeroes at sector %" PRId64 ": %s",
                         sector_num, strerror(-ret));
            return ret;
        }
        sector_num += n;
    }
}

2731
int bdrv_pread(BlockDriverState *bs, int64_t offset, void *buf, int bytes)
B
bellard 已提交
2732
{
2733 2734 2735 2736 2737
    QEMUIOVector qiov;
    struct iovec iov = {
        .iov_base = (void *)buf,
        .iov_len = bytes,
    };
2738
    int ret;
B
bellard 已提交
2739

2740 2741
    if (bytes < 0) {
        return -EINVAL;
B
bellard 已提交
2742 2743
    }

2744 2745 2746 2747
    qemu_iovec_init_external(&qiov, &iov, 1);
    ret = bdrv_prwv_co(bs, offset, &qiov, false, 0);
    if (ret < 0) {
        return ret;
B
bellard 已提交
2748
    }
2749 2750

    return bytes;
B
bellard 已提交
2751 2752
}

2753
int bdrv_pwritev(BlockDriverState *bs, int64_t offset, QEMUIOVector *qiov)
B
bellard 已提交
2754
{
2755
    int ret;
B
bellard 已提交
2756

2757 2758 2759
    ret = bdrv_prwv_co(bs, offset, qiov, true, 0);
    if (ret < 0) {
        return ret;
B
bellard 已提交
2760 2761
    }

2762 2763 2764 2765
    return qiov->size;
}

int bdrv_pwrite(BlockDriverState *bs, int64_t offset,
2766
                const void *buf, int bytes)
2767 2768 2769 2770
{
    QEMUIOVector qiov;
    struct iovec iov = {
        .iov_base   = (void *) buf,
2771
        .iov_len    = bytes,
2772 2773
    };

2774 2775 2776 2777
    if (bytes < 0) {
        return -EINVAL;
    }

2778 2779
    qemu_iovec_init_external(&qiov, &iov, 1);
    return bdrv_pwritev(bs, offset, &qiov);
B
bellard 已提交
2780 2781
}

K
Kevin Wolf 已提交
2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797
/*
 * Writes to the file and ensures that no writes are reordered across this
 * request (acts as a barrier)
 *
 * Returns 0 on success, -errno in error cases.
 */
int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset,
    const void *buf, int count)
{
    int ret;

    ret = bdrv_pwrite(bs, offset, buf, count);
    if (ret < 0) {
        return ret;
    }

2798 2799
    /* No flush needed for cache modes that already do it */
    if (bs->enable_write_cache) {
K
Kevin Wolf 已提交
2800 2801 2802 2803 2804 2805
        bdrv_flush(bs);
    }

    return 0;
}

2806
static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs,
S
Stefan Hajnoczi 已提交
2807 2808 2809 2810 2811 2812 2813 2814 2815
        int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
{
    /* Perform I/O through a temporary buffer so that users who scribble over
     * their read buffer while the operation is in progress do not end up
     * modifying the image file.  This is critical for zero-copy guest I/O
     * where anything might happen inside guest memory.
     */
    void *bounce_buffer;

2816
    BlockDriver *drv = bs->drv;
S
Stefan Hajnoczi 已提交
2817 2818 2819 2820 2821 2822 2823 2824 2825 2826
    struct iovec iov;
    QEMUIOVector bounce_qiov;
    int64_t cluster_sector_num;
    int cluster_nb_sectors;
    size_t skip_bytes;
    int ret;

    /* Cover entire cluster so no additional backing file I/O is required when
     * allocating cluster in the image file.
     */
2827 2828
    bdrv_round_to_clusters(bs, sector_num, nb_sectors,
                           &cluster_sector_num, &cluster_nb_sectors);
S
Stefan Hajnoczi 已提交
2829

2830 2831
    trace_bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors,
                                   cluster_sector_num, cluster_nb_sectors);
S
Stefan Hajnoczi 已提交
2832 2833 2834 2835 2836

    iov.iov_len = cluster_nb_sectors * BDRV_SECTOR_SIZE;
    iov.iov_base = bounce_buffer = qemu_blockalign(bs, iov.iov_len);
    qemu_iovec_init_external(&bounce_qiov, &iov, 1);

2837 2838
    ret = drv->bdrv_co_readv(bs, cluster_sector_num, cluster_nb_sectors,
                             &bounce_qiov);
S
Stefan Hajnoczi 已提交
2839 2840 2841 2842
    if (ret < 0) {
        goto err;
    }

2843 2844
    if (drv->bdrv_co_write_zeroes &&
        buffer_is_zero(bounce_buffer, iov.iov_len)) {
K
Kevin Wolf 已提交
2845
        ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num,
2846
                                      cluster_nb_sectors, 0);
2847
    } else {
2848 2849 2850
        /* This does not change the data on the disk, it is not necessary
         * to flush even in cache=writethrough mode.
         */
2851
        ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors,
S
Stefan Hajnoczi 已提交
2852
                                  &bounce_qiov);
2853 2854
    }

S
Stefan Hajnoczi 已提交
2855 2856 2857 2858 2859 2860 2861 2862 2863
    if (ret < 0) {
        /* It might be okay to ignore write errors for guest requests.  If this
         * is a deliberate copy-on-read then we don't want to ignore the error.
         * Simply report it in all cases.
         */
        goto err;
    }

    skip_bytes = (sector_num - cluster_sector_num) * BDRV_SECTOR_SIZE;
2864 2865
    qemu_iovec_from_buf(qiov, 0, bounce_buffer + skip_bytes,
                        nb_sectors * BDRV_SECTOR_SIZE);
S
Stefan Hajnoczi 已提交
2866 2867 2868 2869 2870 2871

err:
    qemu_vfree(bounce_buffer);
    return ret;
}

2872
/*
2873 2874 2875
 * Forwards an already correctly aligned request to the BlockDriver. This
 * handles copy on read and zeroing after EOF; any other features must be
 * implemented by the caller.
2876
 */
2877
static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
2878
    BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
2879
    int64_t align, QEMUIOVector *qiov, int flags)
K
Kevin Wolf 已提交
2880 2881
{
    BlockDriver *drv = bs->drv;
S
Stefan Hajnoczi 已提交
2882
    int ret;
K
Kevin Wolf 已提交
2883

2884 2885
    int64_t sector_num = offset >> BDRV_SECTOR_BITS;
    unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
K
Kevin Wolf 已提交
2886

2887 2888 2889 2890
    assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
    assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);

    /* Handle Copy on Read and associated serialisation */
2891
    if (flags & BDRV_REQ_COPY_ON_READ) {
2892 2893 2894 2895 2896 2897
        /* If we touch the same cluster it counts as an overlap.  This
         * guarantees that allocating writes will be serialized and not race
         * with each other for the same cluster.  For example, in copy-on-read
         * it ensures that the CoR read and write operations are atomic and
         * guest writes cannot interleave between them. */
        mark_request_serialising(req, bdrv_get_cluster_size(bs));
2898 2899
    }

2900
    wait_serialising_requests(req);
2901

2902
    if (flags & BDRV_REQ_COPY_ON_READ) {
S
Stefan Hajnoczi 已提交
2903 2904
        int pnum;

2905
        ret = bdrv_is_allocated(bs, sector_num, nb_sectors, &pnum);
S
Stefan Hajnoczi 已提交
2906 2907 2908 2909 2910
        if (ret < 0) {
            goto out;
        }

        if (!ret || pnum != nb_sectors) {
2911
            ret = bdrv_co_do_copy_on_readv(bs, sector_num, nb_sectors, qiov);
S
Stefan Hajnoczi 已提交
2912 2913 2914 2915
            goto out;
        }
    }

2916
    /* Forward the request to the BlockDriver */
2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928
    if (!(bs->zero_beyond_eof && bs->growable)) {
        ret = drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov);
    } else {
        /* Read zeros after EOF of growable BDSes */
        int64_t len, total_sectors, max_nb_sectors;

        len = bdrv_getlength(bs);
        if (len < 0) {
            ret = len;
            goto out;
        }

2929
        total_sectors = DIV_ROUND_UP(len, BDRV_SECTOR_SIZE);
2930 2931
        max_nb_sectors = ROUND_UP(MAX(0, total_sectors - sector_num),
                                  align >> BDRV_SECTOR_BITS);
2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946
        if (max_nb_sectors > 0) {
            ret = drv->bdrv_co_readv(bs, sector_num,
                                     MIN(nb_sectors, max_nb_sectors), qiov);
        } else {
            ret = 0;
        }

        /* Reading beyond end of file is supposed to produce zeroes */
        if (ret == 0 && total_sectors < sector_num + nb_sectors) {
            uint64_t offset = MAX(0, total_sectors - sector_num);
            uint64_t bytes = (sector_num + nb_sectors - offset) *
                              BDRV_SECTOR_SIZE;
            qemu_iovec_memset(qiov, offset * BDRV_SECTOR_SIZE, 0, bytes);
        }
    }
S
Stefan Hajnoczi 已提交
2947 2948

out:
S
Stefan Hajnoczi 已提交
2949
    return ret;
K
Kevin Wolf 已提交
2950 2951
}

2952 2953 2954
/*
 * Handle a read request in coroutine context
 */
2955 2956
static int coroutine_fn bdrv_co_do_preadv(BlockDriverState *bs,
    int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
2957 2958 2959
    BdrvRequestFlags flags)
{
    BlockDriver *drv = bs->drv;
2960 2961
    BdrvTrackedRequest req;

2962 2963 2964 2965 2966 2967
    /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */
    uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment);
    uint8_t *head_buf = NULL;
    uint8_t *tail_buf = NULL;
    QEMUIOVector local_qiov;
    bool use_local_qiov = false;
2968 2969 2970 2971 2972
    int ret;

    if (!drv) {
        return -ENOMEDIUM;
    }
2973
    if (bdrv_check_byte_request(bs, offset, bytes)) {
2974 2975 2976 2977 2978 2979 2980 2981 2982
        return -EIO;
    }

    if (bs->copy_on_read) {
        flags |= BDRV_REQ_COPY_ON_READ;
    }

    /* throttling disk I/O */
    if (bs->io_limits_enabled) {
2983
        bdrv_io_limits_intercept(bs, bytes, false);
2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010
    }

    /* Align read if necessary by padding qiov */
    if (offset & (align - 1)) {
        head_buf = qemu_blockalign(bs, align);
        qemu_iovec_init(&local_qiov, qiov->niov + 2);
        qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1));
        qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
        use_local_qiov = true;

        bytes += offset & (align - 1);
        offset = offset & ~(align - 1);
    }

    if ((offset + bytes) & (align - 1)) {
        if (!use_local_qiov) {
            qemu_iovec_init(&local_qiov, qiov->niov + 1);
            qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
            use_local_qiov = true;
        }
        tail_buf = qemu_blockalign(bs, align);
        qemu_iovec_add(&local_qiov, tail_buf,
                       align - ((offset + bytes) & (align - 1)));

        bytes = ROUND_UP(bytes, align);
    }

3011
    tracked_request_begin(&req, bs, offset, bytes, false);
3012
    ret = bdrv_aligned_preadv(bs, &req, offset, bytes, align,
3013 3014
                              use_local_qiov ? &local_qiov : qiov,
                              flags);
3015
    tracked_request_end(&req);
3016 3017 3018 3019 3020

    if (use_local_qiov) {
        qemu_iovec_destroy(&local_qiov);
        qemu_vfree(head_buf);
        qemu_vfree(tail_buf);
3021 3022 3023 3024 3025
    }

    return ret;
}

3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037
static int coroutine_fn bdrv_co_do_readv(BlockDriverState *bs,
    int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
    BdrvRequestFlags flags)
{
    if (nb_sectors < 0 || nb_sectors > (UINT_MAX >> BDRV_SECTOR_BITS)) {
        return -EINVAL;
    }

    return bdrv_co_do_preadv(bs, sector_num << BDRV_SECTOR_BITS,
                             nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
}

3038
int coroutine_fn bdrv_co_readv(BlockDriverState *bs, int64_t sector_num,
K
Kevin Wolf 已提交
3039 3040
    int nb_sectors, QEMUIOVector *qiov)
{
3041
    trace_bdrv_co_readv(bs, sector_num, nb_sectors);
K
Kevin Wolf 已提交
3042

3043 3044 3045 3046 3047 3048 3049 3050 3051 3052
    return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov, 0);
}

int coroutine_fn bdrv_co_copy_on_readv(BlockDriverState *bs,
    int64_t sector_num, int nb_sectors, QEMUIOVector *qiov)
{
    trace_bdrv_co_copy_on_readv(bs, sector_num, nb_sectors);

    return bdrv_co_do_readv(bs, sector_num, nb_sectors, qiov,
                            BDRV_REQ_COPY_ON_READ);
3053 3054
}

3055 3056 3057 3058 3059
/* if no limit is specified in the BlockLimits use a default
 * of 32768 512-byte sectors (16 MiB) per request.
 */
#define MAX_WRITE_ZEROES_DEFAULT 32768

3060
static int coroutine_fn bdrv_co_do_write_zeroes(BlockDriverState *bs,
3061
    int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
3062 3063 3064
{
    BlockDriver *drv = bs->drv;
    QEMUIOVector qiov;
3065 3066
    struct iovec iov = {0};
    int ret = 0;
3067

3068 3069
    int max_write_zeroes = bs->bl.max_write_zeroes ?
                           bs->bl.max_write_zeroes : MAX_WRITE_ZEROES_DEFAULT;
K
Kevin Wolf 已提交
3070

3071 3072 3073
    while (nb_sectors > 0 && !ret) {
        int num = nb_sectors;

3074 3075 3076 3077 3078 3079 3080
        /* Align request.  Block drivers can expect the "bulk" of the request
         * to be aligned.
         */
        if (bs->bl.write_zeroes_alignment
            && num > bs->bl.write_zeroes_alignment) {
            if (sector_num % bs->bl.write_zeroes_alignment != 0) {
                /* Make a small request up to the first aligned sector.  */
3081
                num = bs->bl.write_zeroes_alignment;
3082 3083 3084 3085 3086 3087
                num -= sector_num % bs->bl.write_zeroes_alignment;
            } else if ((sector_num + num) % bs->bl.write_zeroes_alignment != 0) {
                /* Shorten the request to the last aligned sector.  num cannot
                 * underflow because num > bs->bl.write_zeroes_alignment.
                 */
                num -= (sector_num + num) % bs->bl.write_zeroes_alignment;
3088
            }
K
Kevin Wolf 已提交
3089
        }
3090

3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105
        /* limit request size */
        if (num > max_write_zeroes) {
            num = max_write_zeroes;
        }

        ret = -ENOTSUP;
        /* First try the efficient write zeroes operation */
        if (drv->bdrv_co_write_zeroes) {
            ret = drv->bdrv_co_write_zeroes(bs, sector_num, num, flags);
        }

        if (ret == -ENOTSUP) {
            /* Fall back to bounce buffer if write zeroes is unsupported */
            iov.iov_len = num * BDRV_SECTOR_SIZE;
            if (iov.iov_base == NULL) {
3106 3107
                iov.iov_base = qemu_blockalign(bs, num * BDRV_SECTOR_SIZE);
                memset(iov.iov_base, 0, num * BDRV_SECTOR_SIZE);
3108 3109
            }
            qemu_iovec_init_external(&qiov, &iov, 1);
3110

3111
            ret = drv->bdrv_co_writev(bs, sector_num, num, &qiov);
3112 3113 3114 3115 3116 3117 3118 3119

            /* Keep bounce buffer around if it is big enough for all
             * all future requests.
             */
            if (num < max_write_zeroes) {
                qemu_vfree(iov.iov_base);
                iov.iov_base = NULL;
            }
3120 3121 3122 3123 3124
        }

        sector_num += num;
        nb_sectors -= num;
    }
3125 3126 3127 3128 3129

    qemu_vfree(iov.iov_base);
    return ret;
}

3130
/*
3131
 * Forwards an already correctly aligned write request to the BlockDriver.
3132
 */
3133
static int coroutine_fn bdrv_aligned_pwritev(BlockDriverState *bs,
3134 3135
    BdrvTrackedRequest *req, int64_t offset, unsigned int bytes,
    QEMUIOVector *qiov, int flags)
3136 3137
{
    BlockDriver *drv = bs->drv;
3138
    bool waited;
3139
    int ret;
K
Kevin Wolf 已提交
3140

3141 3142
    int64_t sector_num = offset >> BDRV_SECTOR_BITS;
    unsigned int nb_sectors = bytes >> BDRV_SECTOR_BITS;
3143

3144 3145
    assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0);
    assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0);
3146

3147 3148
    waited = wait_serialising_requests(req);
    assert(!waited || !req->serialising);
3149 3150
    assert(req->overlap_offset <= offset);
    assert(offset + bytes <= req->overlap_offset + req->overlap_bytes);
3151

3152
    ret = notifier_with_return_list_notify(&bs->before_write_notifiers, req);
3153 3154 3155 3156

    if (ret < 0) {
        /* Do nothing, write notifier decided to fail this request */
    } else if (flags & BDRV_REQ_ZERO_WRITE) {
3157
        BLKDBG_EVENT(bs, BLKDBG_PWRITEV_ZERO);
3158
        ret = bdrv_co_do_write_zeroes(bs, sector_num, nb_sectors, flags);
3159
    } else {
3160
        BLKDBG_EVENT(bs, BLKDBG_PWRITEV);
3161 3162
        ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);
    }
3163
    BLKDBG_EVENT(bs, BLKDBG_PWRITEV_DONE);
3164

3165 3166 3167 3168
    if (ret == 0 && !bs->enable_write_cache) {
        ret = bdrv_co_flush(bs);
    }

F
Fam Zheng 已提交
3169
    bdrv_set_dirty(bs, sector_num, nb_sectors);
K
Kevin Wolf 已提交
3170 3171 3172 3173

    if (bs->wr_highest_sector < sector_num + nb_sectors - 1) {
        bs->wr_highest_sector = sector_num + nb_sectors - 1;
    }
3174 3175 3176
    if (bs->growable && ret >= 0) {
        bs->total_sectors = MAX(bs->total_sectors, sector_num + nb_sectors);
    }
K
Kevin Wolf 已提交
3177

3178
    return ret;
K
Kevin Wolf 已提交
3179 3180
}

3181 3182 3183
/*
 * Handle a write request in coroutine context
 */
3184 3185
static int coroutine_fn bdrv_co_do_pwritev(BlockDriverState *bs,
    int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
3186 3187
    BdrvRequestFlags flags)
{
3188
    BdrvTrackedRequest req;
3189 3190 3191 3192 3193 3194
    /* TODO Lift BDRV_SECTOR_SIZE restriction in BlockDriver interface */
    uint64_t align = MAX(BDRV_SECTOR_SIZE, bs->request_alignment);
    uint8_t *head_buf = NULL;
    uint8_t *tail_buf = NULL;
    QEMUIOVector local_qiov;
    bool use_local_qiov = false;
3195 3196 3197 3198 3199 3200 3201 3202
    int ret;

    if (!bs->drv) {
        return -ENOMEDIUM;
    }
    if (bs->read_only) {
        return -EACCES;
    }
3203
    if (bdrv_check_byte_request(bs, offset, bytes)) {
3204 3205 3206 3207 3208
        return -EIO;
    }

    /* throttling disk I/O */
    if (bs->io_limits_enabled) {
3209
        bdrv_io_limits_intercept(bs, bytes, true);
3210 3211
    }

3212 3213 3214 3215 3216
    /*
     * Align write if necessary by performing a read-modify-write cycle.
     * Pad qiov with the read parts and be sure to have a tracked request not
     * only for bdrv_aligned_pwritev, but also for the reads of the RMW cycle.
     */
3217
    tracked_request_begin(&req, bs, offset, bytes, true);
3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232

    if (offset & (align - 1)) {
        QEMUIOVector head_qiov;
        struct iovec head_iov;

        mark_request_serialising(&req, align);
        wait_serialising_requests(&req);

        head_buf = qemu_blockalign(bs, align);
        head_iov = (struct iovec) {
            .iov_base   = head_buf,
            .iov_len    = align,
        };
        qemu_iovec_init_external(&head_qiov, &head_iov, 1);

3233
        BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_HEAD);
3234 3235 3236 3237 3238
        ret = bdrv_aligned_preadv(bs, &req, offset & ~(align - 1), align,
                                  align, &head_qiov, 0);
        if (ret < 0) {
            goto fail;
        }
3239
        BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253

        qemu_iovec_init(&local_qiov, qiov->niov + 2);
        qemu_iovec_add(&local_qiov, head_buf, offset & (align - 1));
        qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
        use_local_qiov = true;

        bytes += offset & (align - 1);
        offset = offset & ~(align - 1);
    }

    if ((offset + bytes) & (align - 1)) {
        QEMUIOVector tail_qiov;
        struct iovec tail_iov;
        size_t tail_bytes;
3254
        bool waited;
3255 3256

        mark_request_serialising(&req, align);
3257 3258
        waited = wait_serialising_requests(&req);
        assert(!waited || !use_local_qiov);
3259 3260 3261 3262 3263 3264 3265 3266

        tail_buf = qemu_blockalign(bs, align);
        tail_iov = (struct iovec) {
            .iov_base   = tail_buf,
            .iov_len    = align,
        };
        qemu_iovec_init_external(&tail_qiov, &tail_iov, 1);

3267
        BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_TAIL);
3268 3269 3270 3271 3272
        ret = bdrv_aligned_preadv(bs, &req, (offset + bytes) & ~(align - 1), align,
                                  align, &tail_qiov, 0);
        if (ret < 0) {
            goto fail;
        }
3273
        BLKDBG_EVENT(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291

        if (!use_local_qiov) {
            qemu_iovec_init(&local_qiov, qiov->niov + 1);
            qemu_iovec_concat(&local_qiov, qiov, 0, qiov->size);
            use_local_qiov = true;
        }

        tail_bytes = (offset + bytes) & (align - 1);
        qemu_iovec_add(&local_qiov, tail_buf + tail_bytes, align - tail_bytes);

        bytes = ROUND_UP(bytes, align);
    }

    ret = bdrv_aligned_pwritev(bs, &req, offset, bytes,
                               use_local_qiov ? &local_qiov : qiov,
                               flags);

fail:
3292
    tracked_request_end(&req);
3293

3294 3295 3296
    if (use_local_qiov) {
        qemu_iovec_destroy(&local_qiov);
    }
3297 3298
    qemu_vfree(head_buf);
    qemu_vfree(tail_buf);
3299

3300 3301 3302
    return ret;
}

3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314
static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs,
    int64_t sector_num, int nb_sectors, QEMUIOVector *qiov,
    BdrvRequestFlags flags)
{
    if (nb_sectors < 0 || nb_sectors > (INT_MAX >> BDRV_SECTOR_BITS)) {
        return -EINVAL;
    }

    return bdrv_co_do_pwritev(bs, sector_num << BDRV_SECTOR_BITS,
                              nb_sectors << BDRV_SECTOR_BITS, qiov, flags);
}

3315 3316 3317 3318 3319
int coroutine_fn bdrv_co_writev(BlockDriverState *bs, int64_t sector_num,
    int nb_sectors, QEMUIOVector *qiov)
{
    trace_bdrv_co_writev(bs, sector_num, nb_sectors);

3320 3321 3322 3323
    return bdrv_co_do_writev(bs, sector_num, nb_sectors, qiov, 0);
}

int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs,
3324 3325
                                      int64_t sector_num, int nb_sectors,
                                      BdrvRequestFlags flags)
3326
{
3327
    trace_bdrv_co_write_zeroes(bs, sector_num, nb_sectors, flags);
3328

3329 3330 3331 3332
    if (!(bs->open_flags & BDRV_O_UNMAP)) {
        flags &= ~BDRV_REQ_MAY_UNMAP;
    }

3333
    return bdrv_co_do_writev(bs, sector_num, nb_sectors, NULL,
3334
                             BDRV_REQ_ZERO_WRITE | flags);
3335 3336
}

B
bellard 已提交
3337 3338 3339 3340 3341 3342
/**
 * Truncate file to 'offset' bytes (needed only for file protocols)
 */
int bdrv_truncate(BlockDriverState *bs, int64_t offset)
{
    BlockDriver *drv = bs->drv;
3343
    int ret;
B
bellard 已提交
3344
    if (!drv)
B
bellard 已提交
3345
        return -ENOMEDIUM;
B
bellard 已提交
3346 3347
    if (!drv->bdrv_truncate)
        return -ENOTSUP;
3348 3349
    if (bs->read_only)
        return -EACCES;
M
Marcelo Tosatti 已提交
3350 3351
    if (bdrv_in_use(bs))
        return -EBUSY;
3352 3353 3354
    ret = drv->bdrv_truncate(bs, offset);
    if (ret == 0) {
        ret = refresh_total_sectors(bs, offset >> BDRV_SECTOR_BITS);
3355
        bdrv_dev_resize_cb(bs);
3356 3357
    }
    return ret;
B
bellard 已提交
3358 3359
}

3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378
/**
 * Length of a allocated file in bytes. Sparse files are counted by actual
 * allocated space. Return < 0 if error or unknown.
 */
int64_t bdrv_get_allocated_file_size(BlockDriverState *bs)
{
    BlockDriver *drv = bs->drv;
    if (!drv) {
        return -ENOMEDIUM;
    }
    if (drv->bdrv_get_allocated_file_size) {
        return drv->bdrv_get_allocated_file_size(bs);
    }
    if (bs->file) {
        return bdrv_get_allocated_file_size(bs->file);
    }
    return -ENOTSUP;
}

B
bellard 已提交
3379 3380 3381 3382 3383 3384 3385
/**
 * Length of a file in bytes. Return < 0 if error or unknown.
 */
int64_t bdrv_getlength(BlockDriverState *bs)
{
    BlockDriver *drv = bs->drv;
    if (!drv)
B
bellard 已提交
3386
        return -ENOMEDIUM;
3387

3388 3389 3390 3391
    if (drv->has_variable_length) {
        int ret = refresh_total_sectors(bs, bs->total_sectors);
        if (ret < 0) {
            return ret;
3392
        }
B
bellard 已提交
3393
    }
3394
    return bs->total_sectors * BDRV_SECTOR_SIZE;
B
bellard 已提交
3395 3396
}

B
bellard 已提交
3397
/* return 0 as number of sectors if no device present or error */
3398
void bdrv_get_geometry(BlockDriverState *bs, uint64_t *nb_sectors_ptr)
B
bellard 已提交
3399
{
B
bellard 已提交
3400 3401 3402 3403 3404
    int64_t length;
    length = bdrv_getlength(bs);
    if (length < 0)
        length = 0;
    else
J
Jan Kiszka 已提交
3405
        length = length >> BDRV_SECTOR_BITS;
B
bellard 已提交
3406
    *nb_sectors_ptr = length;
B
bellard 已提交
3407
}
B
bellard 已提交
3408

3409 3410
void bdrv_set_on_error(BlockDriverState *bs, BlockdevOnError on_read_error,
                       BlockdevOnError on_write_error)
3411 3412 3413 3414 3415
{
    bs->on_read_error = on_read_error;
    bs->on_write_error = on_write_error;
}

3416
BlockdevOnError bdrv_get_on_error(BlockDriverState *bs, bool is_read)
3417 3418 3419 3420
{
    return is_read ? bs->on_read_error : bs->on_write_error;
}

3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446
BlockErrorAction bdrv_get_error_action(BlockDriverState *bs, bool is_read, int error)
{
    BlockdevOnError on_err = is_read ? bs->on_read_error : bs->on_write_error;

    switch (on_err) {
    case BLOCKDEV_ON_ERROR_ENOSPC:
        return (error == ENOSPC) ? BDRV_ACTION_STOP : BDRV_ACTION_REPORT;
    case BLOCKDEV_ON_ERROR_STOP:
        return BDRV_ACTION_STOP;
    case BLOCKDEV_ON_ERROR_REPORT:
        return BDRV_ACTION_REPORT;
    case BLOCKDEV_ON_ERROR_IGNORE:
        return BDRV_ACTION_IGNORE;
    default:
        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 bdrv_error_action(BlockDriverState *bs, BlockErrorAction action,
                       bool is_read, int error)
{
    assert(error >= 0);
P
Paolo Bonzini 已提交
3447
    bdrv_emit_qmp_error_event(bs, QEVENT_BLOCK_IO_ERROR, action, is_read);
3448 3449 3450 3451 3452 3453
    if (action == BDRV_ACTION_STOP) {
        vm_stop(RUN_STATE_IO_ERROR);
        bdrv_iostatus_set_err(bs, error);
    }
}

B
bellard 已提交
3454 3455 3456 3457 3458
int bdrv_is_read_only(BlockDriverState *bs)
{
    return bs->read_only;
}

3459 3460 3461 3462 3463
int bdrv_is_sg(BlockDriverState *bs)
{
    return bs->sg;
}

3464 3465 3466 3467 3468
int bdrv_enable_write_cache(BlockDriverState *bs)
{
    return bs->enable_write_cache;
}

3469 3470 3471
void bdrv_set_enable_write_cache(BlockDriverState *bs, bool wce)
{
    bs->enable_write_cache = wce;
3472 3473 3474 3475 3476 3477 3478

    /* so a reopen() will preserve wce */
    if (wce) {
        bs->open_flags |= BDRV_O_CACHE_WB;
    } else {
        bs->open_flags &= ~BDRV_O_CACHE_WB;
    }
3479 3480
}

B
bellard 已提交
3481 3482 3483 3484 3485 3486 3487
int bdrv_is_encrypted(BlockDriverState *bs)
{
    if (bs->backing_hd && bs->backing_hd->encrypted)
        return 1;
    return bs->encrypted;
}

3488 3489 3490 3491 3492 3493 3494 3495 3496
int bdrv_key_required(BlockDriverState *bs)
{
    BlockDriverState *backing_hd = bs->backing_hd;

    if (backing_hd && backing_hd->encrypted && !backing_hd->valid_key)
        return 1;
    return (bs->encrypted && !bs->valid_key);
}

B
bellard 已提交
3497 3498 3499 3500 3501 3502 3503 3504 3505 3506
int bdrv_set_key(BlockDriverState *bs, const char *key)
{
    int ret;
    if (bs->backing_hd && bs->backing_hd->encrypted) {
        ret = bdrv_set_key(bs->backing_hd, key);
        if (ret < 0)
            return ret;
        if (!bs->encrypted)
            return 0;
    }
3507 3508 3509 3510 3511
    if (!bs->encrypted) {
        return -EINVAL;
    } else if (!bs->drv || !bs->drv->bdrv_set_key) {
        return -ENOMEDIUM;
    }
3512
    ret = bs->drv->bdrv_set_key(bs, key);
3513 3514 3515 3516 3517
    if (ret < 0) {
        bs->valid_key = 0;
    } else if (!bs->valid_key) {
        bs->valid_key = 1;
        /* call the change callback now, we skipped it on open */
3518
        bdrv_dev_change_media_cb(bs, true);
3519
    }
3520
    return ret;
B
bellard 已提交
3521 3522
}

3523
const char *bdrv_get_format_name(BlockDriverState *bs)
B
bellard 已提交
3524
{
3525
    return bs->drv ? bs->drv->format_name : NULL;
B
bellard 已提交
3526 3527
}

3528
void bdrv_iterate_format(void (*it)(void *opaque, const char *name),
B
bellard 已提交
3529 3530 3531 3532
                         void *opaque)
{
    BlockDriver *drv;

3533
    QLIST_FOREACH(drv, &bdrv_drivers, list) {
B
bellard 已提交
3534 3535 3536 3537
        it(opaque, drv->format_name);
    }
}

3538
/* This function is to find block backend bs */
B
bellard 已提交
3539 3540 3541 3542
BlockDriverState *bdrv_find(const char *name)
{
    BlockDriverState *bs;

3543
    QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
3544
        if (!strcmp(name, bs->device_name)) {
B
bellard 已提交
3545
            return bs;
3546
        }
B
bellard 已提交
3547 3548 3549 3550
    }
    return NULL;
}

3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565
/* This function is to find a node in the bs graph */
BlockDriverState *bdrv_find_node(const char *node_name)
{
    BlockDriverState *bs;

    assert(node_name);

    QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
        if (!strcmp(node_name, bs->node_name)) {
            return bs;
        }
    }
    return NULL;
}

3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582
/* Put this QMP function here so it can access the static graph_bdrv_states. */
BlockDeviceInfoList *bdrv_named_nodes_list(void)
{
    BlockDeviceInfoList *list, *entry;
    BlockDriverState *bs;

    list = NULL;
    QTAILQ_FOREACH(bs, &graph_bdrv_states, node_list) {
        entry = g_malloc0(sizeof(*entry));
        entry->value = bdrv_block_device_info(bs);
        entry->next = list;
        list = entry;
    }

    return list;
}

3583 3584 3585 3586 3587 3588 3589 3590 3591
BlockDriverState *bdrv_lookup_bs(const char *device,
                                 const char *node_name,
                                 Error **errp)
{
    BlockDriverState *bs = NULL;

    if (device) {
        bs = bdrv_find(device);

3592 3593
        if (bs) {
            return bs;
3594 3595 3596
        }
    }

3597 3598
    if (node_name) {
        bs = bdrv_find_node(node_name);
3599

3600 3601 3602
        if (bs) {
            return bs;
        }
3603 3604
    }

3605 3606 3607 3608
    error_setg(errp, "Cannot find device=%s nor node_name=%s",
                     device ? device : "",
                     node_name ? node_name : "");
    return NULL;
3609 3610
}

M
Markus Armbruster 已提交
3611 3612 3613 3614 3615
BlockDriverState *bdrv_next(BlockDriverState *bs)
{
    if (!bs) {
        return QTAILQ_FIRST(&bdrv_states);
    }
3616
    return QTAILQ_NEXT(bs, device_list);
M
Markus Armbruster 已提交
3617 3618
}

3619
void bdrv_iterate(void (*it)(void *opaque, BlockDriverState *bs), void *opaque)
B
bellard 已提交
3620 3621 3622
{
    BlockDriverState *bs;

3623
    QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
3624
        it(opaque, bs);
B
bellard 已提交
3625 3626 3627
    }
}

B
bellard 已提交
3628 3629 3630 3631 3632
const char *bdrv_get_device_name(BlockDriverState *bs)
{
    return bs->device_name;
}

M
Markus Armbruster 已提交
3633 3634 3635 3636 3637
int bdrv_get_flags(BlockDriverState *bs)
{
    return bs->open_flags;
}

3638
int bdrv_flush_all(void)
A
aliguori 已提交
3639 3640
{
    BlockDriverState *bs;
3641
    int result = 0;
A
aliguori 已提交
3642

3643
    QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
3644 3645 3646 3647
        int ret = bdrv_flush(bs);
        if (ret < 0 && !result) {
            result = ret;
        }
3648
    }
3649 3650

    return result;
A
aliguori 已提交
3651 3652
}

3653 3654 3655 3656 3657
int bdrv_has_zero_init_1(BlockDriverState *bs)
{
    return 1;
}

K
Kevin Wolf 已提交
3658 3659 3660 3661
int bdrv_has_zero_init(BlockDriverState *bs)
{
    assert(bs->drv);

3662 3663 3664 3665 3666
    /* If BS is a copy on write image, it is initialized to
       the contents of the base image, which may not be zeroes.  */
    if (bs->backing_hd) {
        return 0;
    }
K
Kevin Wolf 已提交
3667 3668
    if (bs->drv->bdrv_has_zero_init) {
        return bs->drv->bdrv_has_zero_init(bs);
K
Kevin Wolf 已提交
3669 3670
    }

3671 3672
    /* safe default */
    return 0;
K
Kevin Wolf 已提交
3673 3674
}

3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 3695 3696 3697 3698 3699 3700 3701 3702 3703 3704
bool bdrv_unallocated_blocks_are_zero(BlockDriverState *bs)
{
    BlockDriverInfo bdi;

    if (bs->backing_hd) {
        return false;
    }

    if (bdrv_get_info(bs, &bdi) == 0) {
        return bdi.unallocated_blocks_are_zero;
    }

    return false;
}

bool bdrv_can_write_zeroes_with_unmap(BlockDriverState *bs)
{
    BlockDriverInfo bdi;

    if (bs->backing_hd || !(bs->open_flags & BDRV_O_UNMAP)) {
        return false;
    }

    if (bdrv_get_info(bs, &bdi) == 0) {
        return bdi.can_write_zeroes_with_unmap;
    }

    return false;
}

3705
typedef struct BdrvCoGetBlockStatusData {
3706
    BlockDriverState *bs;
3707
    BlockDriverState *base;
3708 3709 3710
    int64_t sector_num;
    int nb_sectors;
    int *pnum;
3711
    int64_t ret;
3712
    bool done;
3713
} BdrvCoGetBlockStatusData;
3714

3715 3716 3717 3718 3719
/*
 * Returns true iff the specified sector is present in the disk image. Drivers
 * not implementing the functionality are assumed to not support backing files,
 * hence all their sectors are reported as allocated.
 *
3720 3721 3722
 * If 'sector_num' is beyond the end of the disk image the return value is 0
 * and 'pnum' is set to 0.
 *
3723 3724 3725 3726
 * 'pnum' is set to the number of sectors (including and immediately following
 * the specified sector) that are known to be in the same
 * allocated/unallocated state.
 *
3727 3728
 * 'nb_sectors' is the max value 'pnum' should be set to.  If nb_sectors goes
 * beyond the end of the disk image it will be clamped.
3729
 */
3730 3731 3732
static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
                                                     int64_t sector_num,
                                                     int nb_sectors, int *pnum)
3733
{
3734
    int64_t length;
3735
    int64_t n;
3736
    int64_t ret, ret2;
3737

3738 3739 3740 3741 3742 3743
    length = bdrv_getlength(bs);
    if (length < 0) {
        return length;
    }

    if (sector_num >= (length >> BDRV_SECTOR_BITS)) {
3744 3745 3746 3747 3748 3749 3750 3751 3752
        *pnum = 0;
        return 0;
    }

    n = bs->total_sectors - sector_num;
    if (n < nb_sectors) {
        nb_sectors = n;
    }

3753
    if (!bs->drv->bdrv_co_get_block_status) {
3754
        *pnum = nb_sectors;
3755 3756 3757 3758 3759
        ret = BDRV_BLOCK_DATA;
        if (bs->drv->protocol_name) {
            ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE);
        }
        return ret;
3760
    }
3761

3762 3763
    ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum);
    if (ret < 0) {
3764
        *pnum = 0;
3765 3766 3767
        return ret;
    }

3768 3769 3770 3771 3772 3773
    if (ret & BDRV_BLOCK_RAW) {
        assert(ret & BDRV_BLOCK_OFFSET_VALID);
        return bdrv_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,
                                     *pnum, pnum);
    }

3774 3775
    if (!(ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO)) {
        if (bdrv_unallocated_blocks_are_zero(bs)) {
3776
            ret |= BDRV_BLOCK_ZERO;
3777
        } else if (bs->backing_hd) {
3778 3779 3780 3781 3782 3783
            BlockDriverState *bs2 = bs->backing_hd;
            int64_t length2 = bdrv_getlength(bs2);
            if (length2 >= 0 && sector_num >= (length2 >> BDRV_SECTOR_BITS)) {
                ret |= BDRV_BLOCK_ZERO;
            }
        }
3784
    }
3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798

    if (bs->file &&
        (ret & BDRV_BLOCK_DATA) && !(ret & BDRV_BLOCK_ZERO) &&
        (ret & BDRV_BLOCK_OFFSET_VALID)) {
        ret2 = bdrv_co_get_block_status(bs->file, ret >> BDRV_SECTOR_BITS,
                                        *pnum, pnum);
        if (ret2 >= 0) {
            /* Ignore errors.  This is just providing extra information, it
             * is useful but not necessary.
             */
            ret |= (ret2 & BDRV_BLOCK_ZERO);
        }
    }

3799
    return ret;
3800 3801
}

3802 3803
/* Coroutine wrapper for bdrv_get_block_status() */
static void coroutine_fn bdrv_get_block_status_co_entry(void *opaque)
3804
{
3805
    BdrvCoGetBlockStatusData *data = opaque;
3806 3807
    BlockDriverState *bs = data->bs;

3808 3809
    data->ret = bdrv_co_get_block_status(bs, data->sector_num, data->nb_sectors,
                                         data->pnum);
3810 3811 3812 3813
    data->done = true;
}

/*
3814
 * Synchronous wrapper around bdrv_co_get_block_status().
3815
 *
3816
 * See bdrv_co_get_block_status() for details.
3817
 */
3818 3819
int64_t bdrv_get_block_status(BlockDriverState *bs, int64_t sector_num,
                              int nb_sectors, int *pnum)
3820
{
3821
    Coroutine *co;
3822
    BdrvCoGetBlockStatusData data = {
3823 3824 3825 3826 3827 3828 3829
        .bs = bs,
        .sector_num = sector_num,
        .nb_sectors = nb_sectors,
        .pnum = pnum,
        .done = false,
    };

3830 3831
    if (qemu_in_coroutine()) {
        /* Fast-path if already in coroutine context */
3832
        bdrv_get_block_status_co_entry(&data);
3833
    } else {
3834
        co = qemu_coroutine_create(bdrv_get_block_status_co_entry);
3835 3836 3837 3838
        qemu_coroutine_enter(co, &data);
        while (!data.done) {
            qemu_aio_wait();
        }
3839 3840
    }
    return data.ret;
3841 3842
}

3843 3844 3845
int coroutine_fn bdrv_is_allocated(BlockDriverState *bs, int64_t sector_num,
                                   int nb_sectors, int *pnum)
{
3846 3847 3848 3849 3850 3851 3852
    int64_t ret = bdrv_get_block_status(bs, sector_num, nb_sectors, pnum);
    if (ret < 0) {
        return ret;
    }
    return
        (ret & BDRV_BLOCK_DATA) ||
        ((ret & BDRV_BLOCK_ZERO) && !bdrv_has_zero_init(bs));
3853 3854
}

3855 3856 3857 3858 3859 3860 3861 3862 3863 3864 3865 3866
/*
 * Given an image chain: ... -> [BASE] -> [INTER1] -> [INTER2] -> [TOP]
 *
 * Return true if the given sector is allocated in any image between
 * BASE and TOP (inclusive).  BASE can be NULL to check if the given
 * sector is allocated in any image of the chain.  Return false otherwise.
 *
 * 'pnum' is set to the number of sectors (including and immediately following
 *  the specified sector) that are known to be in the same
 *  allocated/unallocated state.
 *
 */
3867 3868 3869 3870
int bdrv_is_allocated_above(BlockDriverState *top,
                            BlockDriverState *base,
                            int64_t sector_num,
                            int nb_sectors, int *pnum)
3871 3872 3873 3874 3875 3876 3877
{
    BlockDriverState *intermediate;
    int ret, n = nb_sectors;

    intermediate = top;
    while (intermediate && intermediate != base) {
        int pnum_inter;
3878 3879
        ret = bdrv_is_allocated(intermediate, sector_num, nb_sectors,
                                &pnum_inter);
3880 3881 3882 3883 3884 3885 3886 3887 3888 3889 3890 3891 3892
        if (ret < 0) {
            return ret;
        } else if (ret) {
            *pnum = pnum_inter;
            return 1;
        }

        /*
         * [sector_num, nb_sectors] is unallocated on top but intermediate
         * might have
         *
         * [sector_num+x, nr_sectors] allocated.
         */
3893 3894 3895
        if (n > pnum_inter &&
            (intermediate == top ||
             sector_num + pnum_inter < intermediate->total_sectors)) {
3896 3897 3898 3899 3900 3901 3902 3903 3904 3905
            n = pnum_inter;
        }

        intermediate = intermediate->backing_hd;
    }

    *pnum = n;
    return 0;
}

3906 3907 3908 3909 3910 3911 3912 3913 3914 3915
const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
{
    if (bs->backing_hd && bs->backing_hd->encrypted)
        return bs->backing_file;
    else if (bs->encrypted)
        return bs->filename;
    else
        return NULL;
}

3916
void bdrv_get_backing_filename(BlockDriverState *bs,
B
bellard 已提交
3917 3918
                               char *filename, int filename_size)
{
K
Kevin Wolf 已提交
3919
    pstrcpy(filename, filename_size, bs->backing_file);
B
bellard 已提交
3920 3921
}

3922
int bdrv_write_compressed(BlockDriverState *bs, int64_t sector_num,
B
bellard 已提交
3923 3924 3925 3926
                          const uint8_t *buf, int nb_sectors)
{
    BlockDriver *drv = bs->drv;
    if (!drv)
B
bellard 已提交
3927
        return -ENOMEDIUM;
B
bellard 已提交
3928 3929
    if (!drv->bdrv_write_compressed)
        return -ENOTSUP;
K
Kevin Wolf 已提交
3930 3931
    if (bdrv_check_request(bs, sector_num, nb_sectors))
        return -EIO;
3932

F
Fam Zheng 已提交
3933
    assert(QLIST_EMPTY(&bs->dirty_bitmaps));
3934

B
bellard 已提交
3935 3936
    return drv->bdrv_write_compressed(bs, sector_num, buf, nb_sectors);
}
3937

B
bellard 已提交
3938 3939 3940 3941
int bdrv_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
{
    BlockDriver *drv = bs->drv;
    if (!drv)
B
bellard 已提交
3942
        return -ENOMEDIUM;
B
bellard 已提交
3943 3944 3945 3946 3947 3948
    if (!drv->bdrv_get_info)
        return -ENOTSUP;
    memset(bdi, 0, sizeof(*bdi));
    return drv->bdrv_get_info(bs, bdi);
}

M
Max Reitz 已提交
3949 3950 3951 3952 3953 3954 3955 3956 3957
ImageInfoSpecific *bdrv_get_specific_info(BlockDriverState *bs)
{
    BlockDriver *drv = bs->drv;
    if (drv && drv->bdrv_get_specific_info) {
        return drv->bdrv_get_specific_info(bs);
    }
    return NULL;
}

3958 3959
int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
                      int64_t pos, int size)
3960 3961 3962 3963 3964 3965 3966 3967 3968 3969 3970 3971
{
    QEMUIOVector qiov;
    struct iovec iov = {
        .iov_base   = (void *) buf,
        .iov_len    = size,
    };

    qemu_iovec_init_external(&qiov, &iov, 1);
    return bdrv_writev_vmstate(bs, &qiov, pos);
}

int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
3972 3973
{
    BlockDriver *drv = bs->drv;
3974 3975

    if (!drv) {
3976
        return -ENOMEDIUM;
3977 3978 3979 3980 3981 3982
    } else if (drv->bdrv_save_vmstate) {
        return drv->bdrv_save_vmstate(bs, qiov, pos);
    } else if (bs->file) {
        return bdrv_writev_vmstate(bs->file, qiov, pos);
    }

3983
    return -ENOTSUP;
3984 3985
}

3986 3987
int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
                      int64_t pos, int size)
3988 3989 3990 3991
{
    BlockDriver *drv = bs->drv;
    if (!drv)
        return -ENOMEDIUM;
3992 3993 3994 3995 3996
    if (drv->bdrv_load_vmstate)
        return drv->bdrv_load_vmstate(bs, buf, pos, size);
    if (bs->file)
        return bdrv_load_vmstate(bs->file, buf, pos, size);
    return -ENOTSUP;
3997 3998
}

K
Kevin Wolf 已提交
3999 4000
void bdrv_debug_event(BlockDriverState *bs, BlkDebugEvent event)
{
4001
    if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
K
Kevin Wolf 已提交
4002 4003 4004
        return;
    }

4005
    bs->drv->bdrv_debug_event(bs, event);
K
Kevin Wolf 已提交
4006 4007 4008 4009 4010 4011 4012 4013 4014 4015 4016 4017 4018 4019 4020 4021
}

int bdrv_debug_breakpoint(BlockDriverState *bs, const char *event,
                          const char *tag)
{
    while (bs && bs->drv && !bs->drv->bdrv_debug_breakpoint) {
        bs = bs->file;
    }

    if (bs && bs->drv && bs->drv->bdrv_debug_breakpoint) {
        return bs->drv->bdrv_debug_breakpoint(bs, event, tag);
    }

    return -ENOTSUP;
}

F
Fam Zheng 已提交
4022 4023 4024 4025 4026 4027 4028 4029 4030 4031 4032 4033 4034
int bdrv_debug_remove_breakpoint(BlockDriverState *bs, const char *tag)
{
    while (bs && bs->drv && !bs->drv->bdrv_debug_remove_breakpoint) {
        bs = bs->file;
    }

    if (bs && bs->drv && bs->drv->bdrv_debug_remove_breakpoint) {
        return bs->drv->bdrv_debug_remove_breakpoint(bs, tag);
    }

    return -ENOTSUP;
}

K
Kevin Wolf 已提交
4035 4036 4037 4038 4039
int bdrv_debug_resume(BlockDriverState *bs, const char *tag)
{
    while (bs && bs->drv && !bs->drv->bdrv_debug_resume) {
        bs = bs->file;
    }
K
Kevin Wolf 已提交
4040

K
Kevin Wolf 已提交
4041 4042 4043 4044 4045 4046 4047 4048 4049 4050 4051 4052 4053 4054 4055 4056 4057 4058
    if (bs && bs->drv && bs->drv->bdrv_debug_resume) {
        return bs->drv->bdrv_debug_resume(bs, tag);
    }

    return -ENOTSUP;
}

bool bdrv_debug_is_suspended(BlockDriverState *bs, const char *tag)
{
    while (bs && bs->drv && !bs->drv->bdrv_debug_is_suspended) {
        bs = bs->file;
    }

    if (bs && bs->drv && bs->drv->bdrv_debug_is_suspended) {
        return bs->drv->bdrv_debug_is_suspended(bs, tag);
    }

    return false;
K
Kevin Wolf 已提交
4059 4060
}

4061 4062 4063 4064 4065
int bdrv_is_snapshot(BlockDriverState *bs)
{
    return !!(bs->open_flags & BDRV_O_SNAPSHOT);
}

4066 4067 4068 4069
/* backing_file can either be relative, or absolute, or a protocol.  If it is
 * relative, it must be relative to the chain.  So, passing in bs->filename
 * from a BDS as backing_file should not be done, as that may be relative to
 * the CWD rather than the chain. */
4070 4071 4072
BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
        const char *backing_file)
{
4073 4074 4075 4076 4077 4078 4079 4080
    char *filename_full = NULL;
    char *backing_file_full = NULL;
    char *filename_tmp = NULL;
    int is_protocol = 0;
    BlockDriverState *curr_bs = NULL;
    BlockDriverState *retval = NULL;

    if (!bs || !bs->drv || !backing_file) {
4081 4082 4083
        return NULL;
    }

4084 4085 4086 4087 4088 4089 4090 4091 4092 4093 4094 4095 4096 4097 4098
    filename_full     = g_malloc(PATH_MAX);
    backing_file_full = g_malloc(PATH_MAX);
    filename_tmp      = g_malloc(PATH_MAX);

    is_protocol = path_has_protocol(backing_file);

    for (curr_bs = bs; curr_bs->backing_hd; curr_bs = curr_bs->backing_hd) {

        /* If either of the filename paths is actually a protocol, then
         * compare unmodified paths; otherwise make paths relative */
        if (is_protocol || path_has_protocol(curr_bs->backing_file)) {
            if (strcmp(backing_file, curr_bs->backing_file) == 0) {
                retval = curr_bs->backing_hd;
                break;
            }
4099
        } else {
4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 4122
            /* If not an absolute filename path, make it relative to the current
             * image's filename path */
            path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
                         backing_file);

            /* We are going to compare absolute pathnames */
            if (!realpath(filename_tmp, filename_full)) {
                continue;
            }

            /* We need to make sure the backing filename we are comparing against
             * is relative to the current image filename (or absolute) */
            path_combine(filename_tmp, PATH_MAX, curr_bs->filename,
                         curr_bs->backing_file);

            if (!realpath(filename_tmp, backing_file_full)) {
                continue;
            }

            if (strcmp(backing_file_full, filename_full) == 0) {
                retval = curr_bs->backing_hd;
                break;
            }
4123 4124 4125
        }
    }

4126 4127 4128 4129
    g_free(filename_full);
    g_free(backing_file_full);
    g_free(filename_tmp);
    return retval;
4130 4131
}

4132 4133 4134 4135 4136 4137 4138 4139 4140 4141 4142 4143 4144
int bdrv_get_backing_file_depth(BlockDriverState *bs)
{
    if (!bs->drv) {
        return 0;
    }

    if (!bs->backing_hd) {
        return 0;
    }

    return 1 + bdrv_get_backing_file_depth(bs->backing_hd);
}

4145 4146 4147 4148 4149 4150 4151 4152 4153 4154 4155 4156 4157 4158 4159 4160
BlockDriverState *bdrv_find_base(BlockDriverState *bs)
{
    BlockDriverState *curr_bs = NULL;

    if (!bs) {
        return NULL;
    }

    curr_bs = bs;

    while (curr_bs->backing_hd) {
        curr_bs = curr_bs->backing_hd;
    }
    return curr_bs;
}

B
bellard 已提交
4161
/**************************************************************/
B
bellard 已提交
4162
/* async I/Os */
B
bellard 已提交
4163

4164
BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num,
4165
                                 QEMUIOVector *qiov, int nb_sectors,
4166
                                 BlockDriverCompletionFunc *cb, void *opaque)
B
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4167
{
4168 4169
    trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque);

P
Paolo Bonzini 已提交
4170
    return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0,
4171
                                 cb, opaque, false);
B
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4172 4173
}

4174 4175 4176
BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num,
                                  QEMUIOVector *qiov, int nb_sectors,
                                  BlockDriverCompletionFunc *cb, void *opaque)
B
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4177
{
4178 4179
    trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque);

P
Paolo Bonzini 已提交
4180
    return bdrv_co_aio_rw_vector(bs, sector_num, qiov, nb_sectors, 0,
4181
                                 cb, opaque, true);
B
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4182 4183
}

P
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4184 4185 4186 4187 4188 4189 4190 4191 4192 4193 4194
BlockDriverAIOCB *bdrv_aio_write_zeroes(BlockDriverState *bs,
        int64_t sector_num, int nb_sectors, BdrvRequestFlags flags,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    trace_bdrv_aio_write_zeroes(bs, sector_num, nb_sectors, flags, opaque);

    return bdrv_co_aio_rw_vector(bs, sector_num, NULL, nb_sectors,
                                 BDRV_REQ_ZERO_WRITE | flags,
                                 cb, opaque, true);
}

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4195 4196 4197 4198 4199 4200 4201 4202 4203 4204 4205 4206 4207 4208 4209 4210 4211 4212

typedef struct MultiwriteCB {
    int error;
    int num_requests;
    int num_callbacks;
    struct {
        BlockDriverCompletionFunc *cb;
        void *opaque;
        QEMUIOVector *free_qiov;
    } callbacks[];
} MultiwriteCB;

static void multiwrite_user_cb(MultiwriteCB *mcb)
{
    int i;

    for (i = 0; i < mcb->num_callbacks; i++) {
        mcb->callbacks[i].cb(mcb->callbacks[i].opaque, mcb->error);
4213 4214 4215
        if (mcb->callbacks[i].free_qiov) {
            qemu_iovec_destroy(mcb->callbacks[i].free_qiov);
        }
4216
        g_free(mcb->callbacks[i].free_qiov);
K
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4217 4218 4219 4220 4221 4222 4223
    }
}

static void multiwrite_cb(void *opaque, int ret)
{
    MultiwriteCB *mcb = opaque;

4224 4225
    trace_multiwrite_cb(mcb, ret);

4226
    if (ret < 0 && !mcb->error) {
K
Kevin Wolf 已提交
4227 4228 4229 4230 4231
        mcb->error = ret;
    }

    mcb->num_requests--;
    if (mcb->num_requests == 0) {
4232
        multiwrite_user_cb(mcb);
4233
        g_free(mcb);
K
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4234 4235 4236 4237 4238
    }
}

static int multiwrite_req_compare(const void *a, const void *b)
{
4239 4240 4241 4242 4243 4244 4245 4246 4247 4248 4249 4250 4251
    const BlockRequest *req1 = a, *req2 = b;

    /*
     * Note that we can't simply subtract req2->sector from req1->sector
     * here as that could overflow the return value.
     */
    if (req1->sector > req2->sector) {
        return 1;
    } else if (req1->sector < req2->sector) {
        return -1;
    } else {
        return 0;
    }
K
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4252 4253 4254 4255 4256 4257 4258 4259 4260 4261 4262 4263 4264 4265 4266 4267 4268 4269 4270 4271 4272
}

/*
 * Takes a bunch of requests and tries to merge them. Returns the number of
 * requests that remain after merging.
 */
static int multiwrite_merge(BlockDriverState *bs, BlockRequest *reqs,
    int num_reqs, MultiwriteCB *mcb)
{
    int i, outidx;

    // Sort requests by start sector
    qsort(reqs, num_reqs, sizeof(*reqs), &multiwrite_req_compare);

    // Check if adjacent requests touch the same clusters. If so, combine them,
    // filling up gaps with zero sectors.
    outidx = 0;
    for (i = 1; i < num_reqs; i++) {
        int merge = 0;
        int64_t oldreq_last = reqs[outidx].sector + reqs[outidx].nb_sectors;

4273
        // Handle exactly sequential writes and overlapping writes.
K
Kevin Wolf 已提交
4274 4275 4276 4277
        if (reqs[i].sector <= oldreq_last) {
            merge = 1;
        }

4278 4279 4280 4281
        if (reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1 > IOV_MAX) {
            merge = 0;
        }

K
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4282 4283
        if (merge) {
            size_t size;
4284
            QEMUIOVector *qiov = g_malloc0(sizeof(*qiov));
K
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4285 4286 4287 4288 4289 4290
            qemu_iovec_init(qiov,
                reqs[outidx].qiov->niov + reqs[i].qiov->niov + 1);

            // Add the first request to the merged one. If the requests are
            // overlapping, drop the last sectors of the first request.
            size = (reqs[i].sector - reqs[outidx].sector) << 9;
4291
            qemu_iovec_concat(qiov, reqs[outidx].qiov, 0, size);
K
Kevin Wolf 已提交
4292

4293 4294
            // We should need to add any zeros between the two requests
            assert (reqs[i].sector <= oldreq_last);
K
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4295 4296

            // Add the second request
4297
            qemu_iovec_concat(qiov, reqs[i].qiov, 0, reqs[i].qiov->size);
K
Kevin Wolf 已提交
4298

4299
            reqs[outidx].nb_sectors = qiov->size >> 9;
K
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4300 4301 4302 4303 4304 4305 4306 4307 4308 4309 4310 4311 4312 4313 4314 4315 4316 4317 4318 4319 4320 4321 4322 4323 4324 4325 4326 4327 4328 4329 4330 4331 4332
            reqs[outidx].qiov = qiov;

            mcb->callbacks[i].free_qiov = reqs[outidx].qiov;
        } else {
            outidx++;
            reqs[outidx].sector     = reqs[i].sector;
            reqs[outidx].nb_sectors = reqs[i].nb_sectors;
            reqs[outidx].qiov       = reqs[i].qiov;
        }
    }

    return outidx + 1;
}

/*
 * Submit multiple AIO write requests at once.
 *
 * On success, the function returns 0 and all requests in the reqs array have
 * been submitted. In error case this function returns -1, and any of the
 * requests may or may not be submitted yet. In particular, this means that the
 * callback will be called for some of the requests, for others it won't. The
 * caller must check the error field of the BlockRequest to wait for the right
 * callbacks (if error != 0, no callback will be called).
 *
 * The implementation may modify the contents of the reqs array, e.g. to merge
 * requests. However, the fields opaque and error are left unmodified as they
 * are used to signal failure for a single request to the caller.
 */
int bdrv_aio_multiwrite(BlockDriverState *bs, BlockRequest *reqs, int num_reqs)
{
    MultiwriteCB *mcb;
    int i;

4333 4334 4335 4336 4337 4338 4339 4340
    /* don't submit writes if we don't have a medium */
    if (bs->drv == NULL) {
        for (i = 0; i < num_reqs; i++) {
            reqs[i].error = -ENOMEDIUM;
        }
        return -1;
    }

K
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4341 4342 4343 4344 4345
    if (num_reqs == 0) {
        return 0;
    }

    // Create MultiwriteCB structure
4346
    mcb = g_malloc0(sizeof(*mcb) + num_reqs * sizeof(*mcb->callbacks));
K
Kevin Wolf 已提交
4347 4348 4349 4350 4351 4352 4353 4354 4355 4356 4357
    mcb->num_requests = 0;
    mcb->num_callbacks = num_reqs;

    for (i = 0; i < num_reqs; i++) {
        mcb->callbacks[i].cb = reqs[i].cb;
        mcb->callbacks[i].opaque = reqs[i].opaque;
    }

    // Check for mergable requests
    num_reqs = multiwrite_merge(bs, reqs, num_reqs, mcb);

4358 4359
    trace_bdrv_aio_multiwrite(mcb, mcb->num_callbacks, num_reqs);

4360 4361
    /* Run the aio requests. */
    mcb->num_requests = num_reqs;
K
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4362
    for (i = 0; i < num_reqs; i++) {
P
Paolo Bonzini 已提交
4363 4364 4365 4366
        bdrv_co_aio_rw_vector(bs, reqs[i].sector, reqs[i].qiov,
                              reqs[i].nb_sectors, reqs[i].flags,
                              multiwrite_cb, mcb,
                              true);
K
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4367 4368 4369 4370 4371
    }

    return 0;
}

B
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4372 4373
void bdrv_aio_cancel(BlockDriverAIOCB *acb)
{
S
Stefan Hajnoczi 已提交
4374
    acb->aiocb_info->cancel(acb);
B
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4375 4376 4377 4378 4379
}

/**************************************************************/
/* async block device emulation */

4380 4381 4382 4383 4384 4385 4386 4387 4388 4389 4390 4391
typedef struct BlockDriverAIOCBSync {
    BlockDriverAIOCB common;
    QEMUBH *bh;
    int ret;
    /* vector translation state */
    QEMUIOVector *qiov;
    uint8_t *bounce;
    int is_write;
} BlockDriverAIOCBSync;

static void bdrv_aio_cancel_em(BlockDriverAIOCB *blockacb)
{
4392 4393
    BlockDriverAIOCBSync *acb =
        container_of(blockacb, BlockDriverAIOCBSync, common);
4394
    qemu_bh_delete(acb->bh);
A
Avi Kivity 已提交
4395
    acb->bh = NULL;
4396 4397 4398
    qemu_aio_release(acb);
}

S
Stefan Hajnoczi 已提交
4399
static const AIOCBInfo bdrv_em_aiocb_info = {
4400 4401 4402 4403
    .aiocb_size         = sizeof(BlockDriverAIOCBSync),
    .cancel             = bdrv_aio_cancel_em,
};

4404
static void bdrv_aio_bh_cb(void *opaque)
B
bellard 已提交
4405
{
4406
    BlockDriverAIOCBSync *acb = opaque;
4407 4408

    if (!acb->is_write)
4409
        qemu_iovec_from_buf(acb->qiov, 0, acb->bounce, acb->qiov->size);
4410
    qemu_vfree(acb->bounce);
4411
    acb->common.cb(acb->common.opaque, acb->ret);
4412
    qemu_bh_delete(acb->bh);
A
Avi Kivity 已提交
4413
    acb->bh = NULL;
4414
    qemu_aio_release(acb);
B
bellard 已提交
4415
}
4416

4417 4418 4419 4420 4421 4422 4423 4424
static BlockDriverAIOCB *bdrv_aio_rw_vector(BlockDriverState *bs,
                                            int64_t sector_num,
                                            QEMUIOVector *qiov,
                                            int nb_sectors,
                                            BlockDriverCompletionFunc *cb,
                                            void *opaque,
                                            int is_write)

B
bellard 已提交
4425
{
4426 4427
    BlockDriverAIOCBSync *acb;

S
Stefan Hajnoczi 已提交
4428
    acb = qemu_aio_get(&bdrv_em_aiocb_info, bs, cb, opaque);
4429 4430
    acb->is_write = is_write;
    acb->qiov = qiov;
4431
    acb->bounce = qemu_blockalign(bs, qiov->size);
4432
    acb->bh = qemu_bh_new(bdrv_aio_bh_cb, acb);
4433 4434

    if (is_write) {
4435
        qemu_iovec_to_buf(acb->qiov, 0, acb->bounce, qiov->size);
4436
        acb->ret = bs->drv->bdrv_write(bs, sector_num, acb->bounce, nb_sectors);
4437
    } else {
4438
        acb->ret = bs->drv->bdrv_read(bs, sector_num, acb->bounce, nb_sectors);
4439 4440
    }

4441
    qemu_bh_schedule(acb->bh);
4442

4443
    return &acb->common;
4444 4445
}

4446 4447
static BlockDriverAIOCB *bdrv_aio_readv_em(BlockDriverState *bs,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
4448
        BlockDriverCompletionFunc *cb, void *opaque)
4449
{
4450 4451
    return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 0);
}
B
bellard 已提交
4452

4453 4454 4455 4456 4457
static BlockDriverAIOCB *bdrv_aio_writev_em(BlockDriverState *bs,
        int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    return bdrv_aio_rw_vector(bs, sector_num, qiov, nb_sectors, cb, opaque, 1);
4458 4459
}

4460 4461 4462 4463 4464

typedef struct BlockDriverAIOCBCoroutine {
    BlockDriverAIOCB common;
    BlockRequest req;
    bool is_write;
K
Kevin Wolf 已提交
4465
    bool *done;
4466 4467 4468 4469 4470
    QEMUBH* bh;
} BlockDriverAIOCBCoroutine;

static void bdrv_aio_co_cancel_em(BlockDriverAIOCB *blockacb)
{
K
Kevin Wolf 已提交
4471 4472 4473 4474 4475 4476 4477 4478
    BlockDriverAIOCBCoroutine *acb =
        container_of(blockacb, BlockDriverAIOCBCoroutine, common);
    bool done = false;

    acb->done = &done;
    while (!done) {
        qemu_aio_wait();
    }
4479 4480
}

S
Stefan Hajnoczi 已提交
4481
static const AIOCBInfo bdrv_em_co_aiocb_info = {
4482 4483 4484 4485
    .aiocb_size         = sizeof(BlockDriverAIOCBCoroutine),
    .cancel             = bdrv_aio_co_cancel_em,
};

P
Paolo Bonzini 已提交
4486
static void bdrv_co_em_bh(void *opaque)
4487 4488 4489 4490
{
    BlockDriverAIOCBCoroutine *acb = opaque;

    acb->common.cb(acb->common.opaque, acb->req.error);
K
Kevin Wolf 已提交
4491 4492 4493 4494 4495

    if (acb->done) {
        *acb->done = true;
    }

4496 4497 4498 4499
    qemu_bh_delete(acb->bh);
    qemu_aio_release(acb);
}

4500 4501 4502 4503 4504 4505 4506 4507
/* Invoke bdrv_co_do_readv/bdrv_co_do_writev */
static void coroutine_fn bdrv_co_do_rw(void *opaque)
{
    BlockDriverAIOCBCoroutine *acb = opaque;
    BlockDriverState *bs = acb->common.bs;

    if (!acb->is_write) {
        acb->req.error = bdrv_co_do_readv(bs, acb->req.sector,
P
Paolo Bonzini 已提交
4508
            acb->req.nb_sectors, acb->req.qiov, acb->req.flags);
4509 4510
    } else {
        acb->req.error = bdrv_co_do_writev(bs, acb->req.sector,
P
Paolo Bonzini 已提交
4511
            acb->req.nb_sectors, acb->req.qiov, acb->req.flags);
4512 4513
    }

P
Paolo Bonzini 已提交
4514
    acb->bh = qemu_bh_new(bdrv_co_em_bh, acb);
4515 4516 4517
    qemu_bh_schedule(acb->bh);
}

4518 4519 4520 4521
static BlockDriverAIOCB *bdrv_co_aio_rw_vector(BlockDriverState *bs,
                                               int64_t sector_num,
                                               QEMUIOVector *qiov,
                                               int nb_sectors,
P
Paolo Bonzini 已提交
4522
                                               BdrvRequestFlags flags,
4523 4524
                                               BlockDriverCompletionFunc *cb,
                                               void *opaque,
4525
                                               bool is_write)
4526 4527 4528 4529
{
    Coroutine *co;
    BlockDriverAIOCBCoroutine *acb;

S
Stefan Hajnoczi 已提交
4530
    acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
4531 4532 4533
    acb->req.sector = sector_num;
    acb->req.nb_sectors = nb_sectors;
    acb->req.qiov = qiov;
P
Paolo Bonzini 已提交
4534
    acb->req.flags = flags;
4535
    acb->is_write = is_write;
K
Kevin Wolf 已提交
4536
    acb->done = NULL;
4537

4538
    co = qemu_coroutine_create(bdrv_co_do_rw);
4539 4540 4541 4542 4543
    qemu_coroutine_enter(co, acb);

    return &acb->common;
}

P
Paolo Bonzini 已提交
4544
static void coroutine_fn bdrv_aio_flush_co_entry(void *opaque)
4545
{
P
Paolo Bonzini 已提交
4546 4547
    BlockDriverAIOCBCoroutine *acb = opaque;
    BlockDriverState *bs = acb->common.bs;
4548

P
Paolo Bonzini 已提交
4549 4550
    acb->req.error = bdrv_co_flush(bs);
    acb->bh = qemu_bh_new(bdrv_co_em_bh, acb);
4551 4552 4553
    qemu_bh_schedule(acb->bh);
}

P
Paolo Bonzini 已提交
4554
BlockDriverAIOCB *bdrv_aio_flush(BlockDriverState *bs,
4555 4556
        BlockDriverCompletionFunc *cb, void *opaque)
{
P
Paolo Bonzini 已提交
4557
    trace_bdrv_aio_flush(bs, opaque);
4558

P
Paolo Bonzini 已提交
4559 4560
    Coroutine *co;
    BlockDriverAIOCBCoroutine *acb;
4561

S
Stefan Hajnoczi 已提交
4562
    acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
K
Kevin Wolf 已提交
4563 4564
    acb->done = NULL;

P
Paolo Bonzini 已提交
4565 4566
    co = qemu_coroutine_create(bdrv_aio_flush_co_entry);
    qemu_coroutine_enter(co, acb);
4567 4568 4569 4570

    return &acb->common;
}

4571 4572 4573 4574 4575 4576 4577 4578 4579 4580 4581 4582 4583 4584 4585 4586 4587 4588 4589
static void coroutine_fn bdrv_aio_discard_co_entry(void *opaque)
{
    BlockDriverAIOCBCoroutine *acb = opaque;
    BlockDriverState *bs = acb->common.bs;

    acb->req.error = bdrv_co_discard(bs, acb->req.sector, acb->req.nb_sectors);
    acb->bh = qemu_bh_new(bdrv_co_em_bh, acb);
    qemu_bh_schedule(acb->bh);
}

BlockDriverAIOCB *bdrv_aio_discard(BlockDriverState *bs,
        int64_t sector_num, int nb_sectors,
        BlockDriverCompletionFunc *cb, void *opaque)
{
    Coroutine *co;
    BlockDriverAIOCBCoroutine *acb;

    trace_bdrv_aio_discard(bs, sector_num, nb_sectors, opaque);

S
Stefan Hajnoczi 已提交
4590
    acb = qemu_aio_get(&bdrv_em_co_aiocb_info, bs, cb, opaque);
4591 4592
    acb->req.sector = sector_num;
    acb->req.nb_sectors = nb_sectors;
K
Kevin Wolf 已提交
4593
    acb->done = NULL;
4594 4595 4596 4597 4598 4599
    co = qemu_coroutine_create(bdrv_aio_discard_co_entry);
    qemu_coroutine_enter(co, acb);

    return &acb->common;
}

B
bellard 已提交
4600 4601
void bdrv_init(void)
{
4602
    module_call_init(MODULE_INIT_BLOCK);
B
bellard 已提交
4603
}
4604

4605 4606 4607 4608 4609 4610
void bdrv_init_with_whitelist(void)
{
    use_bdrv_whitelist = 1;
    bdrv_init();
}

S
Stefan Hajnoczi 已提交
4611
void *qemu_aio_get(const AIOCBInfo *aiocb_info, BlockDriverState *bs,
4612
                   BlockDriverCompletionFunc *cb, void *opaque)
4613 4614 4615
{
    BlockDriverAIOCB *acb;

S
Stefan Hajnoczi 已提交
4616 4617
    acb = g_slice_alloc(aiocb_info->aiocb_size);
    acb->aiocb_info = aiocb_info;
4618 4619 4620 4621 4622 4623 4624 4625
    acb->bs = bs;
    acb->cb = cb;
    acb->opaque = opaque;
    return acb;
}

void qemu_aio_release(void *p)
{
4626
    BlockDriverAIOCB *acb = p;
S
Stefan Hajnoczi 已提交
4627
    g_slice_free1(acb->aiocb_info->aiocb_size, acb);
4628
}
B
bellard 已提交
4629

4630 4631 4632 4633 4634 4635 4636 4637 4638 4639 4640 4641 4642 4643 4644 4645 4646 4647 4648 4649 4650 4651 4652 4653 4654 4655
/**************************************************************/
/* Coroutine block device emulation */

typedef struct CoroutineIOCompletion {
    Coroutine *coroutine;
    int ret;
} CoroutineIOCompletion;

static void bdrv_co_io_em_complete(void *opaque, int ret)
{
    CoroutineIOCompletion *co = opaque;

    co->ret = ret;
    qemu_coroutine_enter(co->coroutine, NULL);
}

static int coroutine_fn bdrv_co_io_em(BlockDriverState *bs, int64_t sector_num,
                                      int nb_sectors, QEMUIOVector *iov,
                                      bool is_write)
{
    CoroutineIOCompletion co = {
        .coroutine = qemu_coroutine_self(),
    };
    BlockDriverAIOCB *acb;

    if (is_write) {
4656 4657
        acb = bs->drv->bdrv_aio_writev(bs, sector_num, iov, nb_sectors,
                                       bdrv_co_io_em_complete, &co);
4658
    } else {
4659 4660
        acb = bs->drv->bdrv_aio_readv(bs, sector_num, iov, nb_sectors,
                                      bdrv_co_io_em_complete, &co);
4661 4662
    }

4663
    trace_bdrv_co_io_em(bs, sector_num, nb_sectors, is_write, acb);
4664 4665 4666 4667 4668 4669 4670 4671 4672 4673 4674 4675 4676 4677 4678 4679 4680 4681 4682 4683 4684 4685
    if (!acb) {
        return -EIO;
    }
    qemu_coroutine_yield();

    return co.ret;
}

static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,
                                         int64_t sector_num, int nb_sectors,
                                         QEMUIOVector *iov)
{
    return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, false);
}

static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
                                         int64_t sector_num, int nb_sectors,
                                         QEMUIOVector *iov)
{
    return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true);
}

P
Paolo Bonzini 已提交
4686
static void coroutine_fn bdrv_flush_co_entry(void *opaque)
4687
{
P
Paolo Bonzini 已提交
4688 4689 4690 4691 4692 4693 4694
    RwCo *rwco = opaque;

    rwco->ret = bdrv_co_flush(rwco->bs);
}

int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
{
K
Kevin Wolf 已提交
4695 4696
    int ret;

4697
    if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs)) {
P
Paolo Bonzini 已提交
4698
        return 0;
K
Kevin Wolf 已提交
4699 4700
    }

4701
    /* Write back cached data to the OS even with cache=unsafe */
4702
    BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_OS);
K
Kevin Wolf 已提交
4703 4704 4705 4706 4707 4708 4709
    if (bs->drv->bdrv_co_flush_to_os) {
        ret = bs->drv->bdrv_co_flush_to_os(bs);
        if (ret < 0) {
            return ret;
        }
    }

4710 4711
    /* But don't actually force it to the disk with cache=unsafe */
    if (bs->open_flags & BDRV_O_NO_FLUSH) {
4712
        goto flush_parent;
4713 4714
    }

4715
    BLKDBG_EVENT(bs->file, BLKDBG_FLUSH_TO_DISK);
K
Kevin Wolf 已提交
4716
    if (bs->drv->bdrv_co_flush_to_disk) {
4717
        ret = bs->drv->bdrv_co_flush_to_disk(bs);
P
Paolo Bonzini 已提交
4718 4719 4720 4721 4722 4723 4724 4725
    } else if (bs->drv->bdrv_aio_flush) {
        BlockDriverAIOCB *acb;
        CoroutineIOCompletion co = {
            .coroutine = qemu_coroutine_self(),
        };

        acb = bs->drv->bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co);
        if (acb == NULL) {
4726
            ret = -EIO;
P
Paolo Bonzini 已提交
4727 4728
        } else {
            qemu_coroutine_yield();
4729
            ret = co.ret;
P
Paolo Bonzini 已提交
4730 4731 4732 4733 4734 4735 4736 4737 4738 4739 4740 4741 4742
        }
    } else {
        /*
         * Some block drivers always operate in either writethrough or unsafe
         * mode and don't support bdrv_flush therefore. Usually qemu doesn't
         * know how the server works (because the behaviour is hardcoded or
         * depends on server-side configuration), so we can't ensure that
         * everything is safe on disk. Returning an error doesn't work because
         * that would break guests even if the server operates in writethrough
         * mode.
         *
         * Let's hope the user knows what he's doing.
         */
4743
        ret = 0;
P
Paolo Bonzini 已提交
4744
    }
4745 4746 4747 4748 4749 4750 4751
    if (ret < 0) {
        return ret;
    }

    /* Now flush the underlying protocol.  It will also have BDRV_O_NO_FLUSH
     * in the case of cache=unsafe, so there are no useless flushes.
     */
4752
flush_parent:
4753
    return bdrv_co_flush(bs->file);
P
Paolo Bonzini 已提交
4754 4755
}

4756 4757 4758 4759 4760 4761 4762 4763 4764 4765 4766
void bdrv_invalidate_cache(BlockDriverState *bs)
{
    if (bs->drv && bs->drv->bdrv_invalidate_cache) {
        bs->drv->bdrv_invalidate_cache(bs);
    }
}

void bdrv_invalidate_cache_all(void)
{
    BlockDriverState *bs;

4767
    QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
4768 4769 4770 4771
        bdrv_invalidate_cache(bs);
    }
}

4772 4773 4774 4775
void bdrv_clear_incoming_migration_all(void)
{
    BlockDriverState *bs;

4776
    QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
4777 4778 4779 4780
        bs->open_flags = bs->open_flags & ~(BDRV_O_INCOMING);
    }
}

P
Paolo Bonzini 已提交
4781 4782 4783 4784 4785 4786
int bdrv_flush(BlockDriverState *bs)
{
    Coroutine *co;
    RwCo rwco = {
        .bs = bs,
        .ret = NOT_DONE,
4787 4788
    };

P
Paolo Bonzini 已提交
4789 4790 4791 4792 4793 4794 4795 4796 4797
    if (qemu_in_coroutine()) {
        /* Fast-path if already in coroutine context */
        bdrv_flush_co_entry(&rwco);
    } else {
        co = qemu_coroutine_create(bdrv_flush_co_entry);
        qemu_coroutine_enter(co, &rwco);
        while (rwco.ret == NOT_DONE) {
            qemu_aio_wait();
        }
4798
    }
P
Paolo Bonzini 已提交
4799 4800

    return rwco.ret;
4801 4802
}

4803 4804 4805 4806 4807 4808
typedef struct DiscardCo {
    BlockDriverState *bs;
    int64_t sector_num;
    int nb_sectors;
    int ret;
} DiscardCo;
4809 4810
static void coroutine_fn bdrv_discard_co_entry(void *opaque)
{
4811
    DiscardCo *rwco = opaque;
4812 4813 4814 4815

    rwco->ret = bdrv_co_discard(rwco->bs, rwco->sector_num, rwco->nb_sectors);
}

4816 4817 4818 4819 4820
/* if no limit is specified in the BlockLimits use a default
 * of 32768 512-byte sectors (16 MiB) per request.
 */
#define MAX_DISCARD_DEFAULT 32768

4821 4822 4823
int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
                                 int nb_sectors)
{
4824 4825
    int max_discard;

4826 4827 4828 4829 4830 4831
    if (!bs->drv) {
        return -ENOMEDIUM;
    } else if (bdrv_check_request(bs, sector_num, nb_sectors)) {
        return -EIO;
    } else if (bs->read_only) {
        return -EROFS;
4832 4833
    }

F
Fam Zheng 已提交
4834
    bdrv_reset_dirty(bs, sector_num, nb_sectors);
4835

P
Paolo Bonzini 已提交
4836 4837 4838 4839 4840
    /* Do nothing if disabled.  */
    if (!(bs->open_flags & BDRV_O_UNMAP)) {
        return 0;
    }

4841 4842 4843
    if (!bs->drv->bdrv_co_discard && !bs->drv->bdrv_aio_discard) {
        return 0;
    }
4844

4845 4846 4847 4848
    max_discard = bs->bl.max_discard ?  bs->bl.max_discard : MAX_DISCARD_DEFAULT;
    while (nb_sectors > 0) {
        int ret;
        int num = nb_sectors;
4849

4850 4851 4852 4853 4854 4855
        /* align request */
        if (bs->bl.discard_alignment &&
            num >= bs->bl.discard_alignment &&
            sector_num % bs->bl.discard_alignment) {
            if (num > bs->bl.discard_alignment) {
                num = bs->bl.discard_alignment;
4856
            }
4857 4858
            num -= sector_num % bs->bl.discard_alignment;
        }
4859

4860 4861 4862 4863
        /* limit request size */
        if (num > max_discard) {
            num = max_discard;
        }
4864

4865
        if (bs->drv->bdrv_co_discard) {
4866
            ret = bs->drv->bdrv_co_discard(bs, sector_num, num);
4867 4868 4869 4870 4871 4872 4873 4874 4875 4876 4877 4878 4879
        } else {
            BlockDriverAIOCB *acb;
            CoroutineIOCompletion co = {
                .coroutine = qemu_coroutine_self(),
            };

            acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors,
                                            bdrv_co_io_em_complete, &co);
            if (acb == NULL) {
                return -EIO;
            } else {
                qemu_coroutine_yield();
                ret = co.ret;
4880 4881
            }
        }
4882
        if (ret && ret != -ENOTSUP) {
4883
            return ret;
4884
        }
4885 4886 4887

        sector_num += num;
        nb_sectors -= num;
4888
    }
4889
    return 0;
4890 4891 4892 4893 4894
}

int bdrv_discard(BlockDriverState *bs, int64_t sector_num, int nb_sectors)
{
    Coroutine *co;
4895
    DiscardCo rwco = {
4896 4897 4898 4899 4900 4901 4902 4903 4904 4905 4906 4907 4908 4909 4910 4911 4912 4913 4914 4915
        .bs = bs,
        .sector_num = sector_num,
        .nb_sectors = nb_sectors,
        .ret = NOT_DONE,
    };

    if (qemu_in_coroutine()) {
        /* Fast-path if already in coroutine context */
        bdrv_discard_co_entry(&rwco);
    } else {
        co = qemu_coroutine_create(bdrv_discard_co_entry);
        qemu_coroutine_enter(co, &rwco);
        while (rwco.ret == NOT_DONE) {
            qemu_aio_wait();
        }
    }

    return rwco.ret;
}

B
bellard 已提交
4916 4917 4918 4919 4920 4921 4922 4923 4924
/**************************************************************/
/* removable device support */

/**
 * Return TRUE if the media is present
 */
int bdrv_is_inserted(BlockDriverState *bs)
{
    BlockDriver *drv = bs->drv;
4925

B
bellard 已提交
4926 4927 4928
    if (!drv)
        return 0;
    if (!drv->bdrv_is_inserted)
4929 4930
        return 1;
    return drv->bdrv_is_inserted(bs);
B
bellard 已提交
4931 4932 4933
}

/**
4934 4935
 * Return whether the media changed since the last call to this
 * function, or -ENOTSUP if we don't know.  Most drivers don't know.
B
bellard 已提交
4936 4937 4938 4939 4940
 */
int bdrv_media_changed(BlockDriverState *bs)
{
    BlockDriver *drv = bs->drv;

4941 4942 4943 4944
    if (drv && drv->bdrv_media_changed) {
        return drv->bdrv_media_changed(bs);
    }
    return -ENOTSUP;
B
bellard 已提交
4945 4946 4947 4948 4949
}

/**
 * If eject_flag is TRUE, eject the media. Otherwise, close the tray
 */
4950
void bdrv_eject(BlockDriverState *bs, bool eject_flag)
B
bellard 已提交
4951 4952 4953
{
    BlockDriver *drv = bs->drv;

4954 4955
    if (drv && drv->bdrv_eject) {
        drv->bdrv_eject(bs, eject_flag);
B
bellard 已提交
4956
    }
4957 4958 4959 4960

    if (bs->device_name[0] != '\0') {
        bdrv_emit_qmp_eject_event(bs, eject_flag);
    }
B
bellard 已提交
4961 4962 4963 4964 4965 4966
}

/**
 * Lock or unlock the media (if it is locked, the user won't be able
 * to eject it manually).
 */
4967
void bdrv_lock_medium(BlockDriverState *bs, bool locked)
B
bellard 已提交
4968 4969 4970
{
    BlockDriver *drv = bs->drv;

4971
    trace_bdrv_lock_medium(bs, locked);
S
Stefan Hajnoczi 已提交
4972

4973 4974
    if (drv && drv->bdrv_lock_medium) {
        drv->bdrv_lock_medium(bs, locked);
B
bellard 已提交
4975 4976
    }
}
4977 4978 4979 4980 4981 4982 4983 4984 4985 4986 4987

/* needed for generic scsi interface */

int bdrv_ioctl(BlockDriverState *bs, unsigned long int req, void *buf)
{
    BlockDriver *drv = bs->drv;

    if (drv && drv->bdrv_ioctl)
        return drv->bdrv_ioctl(bs, req, buf);
    return -ENOTSUP;
}
4988

4989 4990 4991
BlockDriverAIOCB *bdrv_aio_ioctl(BlockDriverState *bs,
        unsigned long int req, void *buf,
        BlockDriverCompletionFunc *cb, void *opaque)
4992
{
4993
    BlockDriver *drv = bs->drv;
4994

4995 4996 4997
    if (drv && drv->bdrv_aio_ioctl)
        return drv->bdrv_aio_ioctl(bs, req, buf, cb, opaque);
    return NULL;
4998
}
4999

5000
void bdrv_set_guest_block_size(BlockDriverState *bs, int align)
5001
{
5002
    bs->guest_block_size = align;
5003
}
5004

5005 5006
void *qemu_blockalign(BlockDriverState *bs, size_t size)
{
5007
    return qemu_memalign(bdrv_opt_mem_align(bs), size);
5008
}
5009

5010 5011 5012 5013 5014 5015
/*
 * Check if all memory in this vector is sector aligned.
 */
bool bdrv_qiov_is_aligned(BlockDriverState *bs, QEMUIOVector *qiov)
{
    int i;
5016
    size_t alignment = bdrv_opt_mem_align(bs);
5017 5018

    for (i = 0; i < qiov->niov; i++) {
5019
        if ((uintptr_t) qiov->iov[i].iov_base % alignment) {
5020
            return false;
5021
        }
5022
        if (qiov->iov[i].iov_len % alignment) {
5023
            return false;
5024 5025 5026 5027 5028 5029
        }
    }

    return true;
}

F
Fam Zheng 已提交
5030
BdrvDirtyBitmap *bdrv_create_dirty_bitmap(BlockDriverState *bs, int granularity)
5031 5032
{
    int64_t bitmap_size;
F
Fam Zheng 已提交
5033
    BdrvDirtyBitmap *bitmap;
5034

5035 5036
    assert((granularity & (granularity - 1)) == 0);

F
Fam Zheng 已提交
5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 5047 5048 5049 5050 5051 5052 5053 5054
    granularity >>= BDRV_SECTOR_BITS;
    assert(granularity);
    bitmap_size = (bdrv_getlength(bs) >> BDRV_SECTOR_BITS);
    bitmap = g_malloc0(sizeof(BdrvDirtyBitmap));
    bitmap->bitmap = hbitmap_alloc(bitmap_size, ffs(granularity) - 1);
    QLIST_INSERT_HEAD(&bs->dirty_bitmaps, bitmap, list);
    return bitmap;
}

void bdrv_release_dirty_bitmap(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
{
    BdrvDirtyBitmap *bm, *next;
    QLIST_FOREACH_SAFE(bm, &bs->dirty_bitmaps, list, next) {
        if (bm == bitmap) {
            QLIST_REMOVE(bitmap, list);
            hbitmap_free(bitmap->bitmap);
            g_free(bitmap);
            return;
5055
        }
5056 5057 5058
    }
}

F
Fam Zheng 已提交
5059 5060 5061 5062 5063 5064 5065 5066 5067 5068 5069 5070 5071 5072 5073 5074 5075 5076 5077 5078
BlockDirtyInfoList *bdrv_query_dirty_bitmaps(BlockDriverState *bs)
{
    BdrvDirtyBitmap *bm;
    BlockDirtyInfoList *list = NULL;
    BlockDirtyInfoList **plist = &list;

    QLIST_FOREACH(bm, &bs->dirty_bitmaps, list) {
        BlockDirtyInfo *info = g_malloc0(sizeof(BlockDirtyInfo));
        BlockDirtyInfoList *entry = g_malloc0(sizeof(BlockDirtyInfoList));
        info->count = bdrv_get_dirty_count(bs, bm);
        info->granularity =
            ((int64_t) BDRV_SECTOR_SIZE << hbitmap_granularity(bm->bitmap));
        entry->value = info;
        *plist = entry;
        plist = &entry->next;
    }

    return list;
}

F
Fam Zheng 已提交
5079
int bdrv_get_dirty(BlockDriverState *bs, BdrvDirtyBitmap *bitmap, int64_t sector)
5080
{
F
Fam Zheng 已提交
5081 5082
    if (bitmap) {
        return hbitmap_get(bitmap->bitmap, sector);
5083 5084 5085 5086 5087
    } else {
        return 0;
    }
}

F
Fam Zheng 已提交
5088 5089
void bdrv_dirty_iter_init(BlockDriverState *bs,
                          BdrvDirtyBitmap *bitmap, HBitmapIter *hbi)
5090
{
F
Fam Zheng 已提交
5091
    hbitmap_iter_init(hbi, bitmap->bitmap, 0);
5092 5093 5094 5095 5096
}

void bdrv_set_dirty(BlockDriverState *bs, int64_t cur_sector,
                    int nr_sectors)
{
F
Fam Zheng 已提交
5097 5098 5099 5100
    BdrvDirtyBitmap *bitmap;
    QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
        hbitmap_set(bitmap->bitmap, cur_sector, nr_sectors);
    }
5101 5102
}

F
Fam Zheng 已提交
5103
void bdrv_reset_dirty(BlockDriverState *bs, int64_t cur_sector, int nr_sectors)
5104
{
F
Fam Zheng 已提交
5105 5106 5107 5108
    BdrvDirtyBitmap *bitmap;
    QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
        hbitmap_reset(bitmap->bitmap, cur_sector, nr_sectors);
    }
5109
}
5110

F
Fam Zheng 已提交
5111
int64_t bdrv_get_dirty_count(BlockDriverState *bs, BdrvDirtyBitmap *bitmap)
5112
{
F
Fam Zheng 已提交
5113
    return hbitmap_count(bitmap->bitmap);
5114
}
J
Jes Sorensen 已提交
5115

5116 5117 5118 5119 5120 5121 5122 5123 5124 5125 5126 5127 5128 5129 5130 5131 5132
/* Get a reference to bs */
void bdrv_ref(BlockDriverState *bs)
{
    bs->refcnt++;
}

/* Release a previously grabbed reference to bs.
 * If after releasing, reference count is zero, the BlockDriverState is
 * deleted. */
void bdrv_unref(BlockDriverState *bs)
{
    assert(bs->refcnt > 0);
    if (--bs->refcnt == 0) {
        bdrv_delete(bs);
    }
}

5133 5134 5135 5136 5137 5138 5139 5140 5141 5142 5143
void bdrv_set_in_use(BlockDriverState *bs, int in_use)
{
    assert(bs->in_use != in_use);
    bs->in_use = in_use;
}

int bdrv_in_use(BlockDriverState *bs)
{
    return bs->in_use;
}

5144 5145
void bdrv_iostatus_enable(BlockDriverState *bs)
{
5146
    bs->iostatus_enabled = true;
5147
    bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
5148 5149 5150 5151 5152 5153
}

/* The I/O status is only enabled if the drive explicitly
 * enables it _and_ the VM is configured to stop on errors */
bool bdrv_iostatus_is_enabled(const BlockDriverState *bs)
{
5154
    return (bs->iostatus_enabled &&
5155 5156 5157
           (bs->on_write_error == BLOCKDEV_ON_ERROR_ENOSPC ||
            bs->on_write_error == BLOCKDEV_ON_ERROR_STOP   ||
            bs->on_read_error == BLOCKDEV_ON_ERROR_STOP));
5158 5159 5160 5161
}

void bdrv_iostatus_disable(BlockDriverState *bs)
{
5162
    bs->iostatus_enabled = false;
5163 5164 5165 5166 5167
}

void bdrv_iostatus_reset(BlockDriverState *bs)
{
    if (bdrv_iostatus_is_enabled(bs)) {
5168
        bs->iostatus = BLOCK_DEVICE_IO_STATUS_OK;
5169 5170 5171
        if (bs->job) {
            block_job_iostatus_reset(bs->job);
        }
5172 5173 5174 5175 5176
    }
}

void bdrv_iostatus_set_err(BlockDriverState *bs, int error)
{
5177 5178
    assert(bdrv_iostatus_is_enabled(bs));
    if (bs->iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
5179 5180
        bs->iostatus = error == ENOSPC ? BLOCK_DEVICE_IO_STATUS_NOSPACE :
                                         BLOCK_DEVICE_IO_STATUS_FAILED;
5181 5182 5183
    }
}

5184 5185 5186 5187 5188 5189 5190
void
bdrv_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie, int64_t bytes,
        enum BlockAcctType type)
{
    assert(type < BDRV_MAX_IOTYPE);

    cookie->bytes = bytes;
C
Christoph Hellwig 已提交
5191
    cookie->start_time_ns = get_clock();
5192 5193 5194 5195 5196 5197 5198 5199 5200 5201
    cookie->type = type;
}

void
bdrv_acct_done(BlockDriverState *bs, BlockAcctCookie *cookie)
{
    assert(cookie->type < BDRV_MAX_IOTYPE);

    bs->nr_bytes[cookie->type] += cookie->bytes;
    bs->nr_ops[cookie->type]++;
C
Christoph Hellwig 已提交
5202
    bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns;
5203 5204
}

5205 5206
void bdrv_img_create(const char *filename, const char *fmt,
                     const char *base_filename, const char *base_fmt,
5207 5208
                     char *options, uint64_t img_size, int flags,
                     Error **errp, bool quiet)
J
Jes Sorensen 已提交
5209 5210
{
    QEMUOptionParameter *param = NULL, *create_options = NULL;
K
Kevin Wolf 已提交
5211
    QEMUOptionParameter *backing_fmt, *backing_file, *size;
J
Jes Sorensen 已提交
5212
    BlockDriver *drv, *proto_drv;
5213
    BlockDriver *backing_drv = NULL;
5214
    Error *local_err = NULL;
J
Jes Sorensen 已提交
5215 5216 5217 5218 5219
    int ret = 0;

    /* Find driver and parse its options */
    drv = bdrv_find_format(fmt);
    if (!drv) {
5220
        error_setg(errp, "Unknown file format '%s'", fmt);
5221
        return;
J
Jes Sorensen 已提交
5222 5223
    }

5224
    proto_drv = bdrv_find_protocol(filename, true);
J
Jes Sorensen 已提交
5225
    if (!proto_drv) {
5226
        error_setg(errp, "Unknown protocol '%s'", filename);
5227
        return;
J
Jes Sorensen 已提交
5228 5229 5230 5231 5232 5233 5234 5235 5236 5237 5238 5239 5240 5241 5242 5243
    }

    create_options = append_option_parameters(create_options,
                                              drv->create_options);
    create_options = append_option_parameters(create_options,
                                              proto_drv->create_options);

    /* Create parameter list with default values */
    param = parse_option_parameters("", create_options, param);

    set_option_parameter_int(param, BLOCK_OPT_SIZE, img_size);

    /* Parse -o options */
    if (options) {
        param = parse_option_parameters(options, create_options, param);
        if (param == NULL) {
5244
            error_setg(errp, "Invalid options for file format '%s'.", fmt);
J
Jes Sorensen 已提交
5245 5246 5247 5248 5249 5250 5251
            goto out;
        }
    }

    if (base_filename) {
        if (set_option_parameter(param, BLOCK_OPT_BACKING_FILE,
                                 base_filename)) {
5252 5253
            error_setg(errp, "Backing file not supported for file format '%s'",
                       fmt);
J
Jes Sorensen 已提交
5254 5255 5256 5257 5258 5259
            goto out;
        }
    }

    if (base_fmt) {
        if (set_option_parameter(param, BLOCK_OPT_BACKING_FMT, base_fmt)) {
5260 5261
            error_setg(errp, "Backing file format not supported for file "
                             "format '%s'", fmt);
J
Jes Sorensen 已提交
5262 5263 5264 5265
            goto out;
        }
    }

5266 5267 5268
    backing_file = get_option_parameter(param, BLOCK_OPT_BACKING_FILE);
    if (backing_file && backing_file->value.s) {
        if (!strcmp(filename, backing_file->value.s)) {
5269 5270
            error_setg(errp, "Error: Trying to create an image with the "
                             "same filename as the backing file");
5271 5272 5273 5274
            goto out;
        }
    }

J
Jes Sorensen 已提交
5275 5276
    backing_fmt = get_option_parameter(param, BLOCK_OPT_BACKING_FMT);
    if (backing_fmt && backing_fmt->value.s) {
5277 5278
        backing_drv = bdrv_find_format(backing_fmt->value.s);
        if (!backing_drv) {
5279 5280
            error_setg(errp, "Unknown backing file format '%s'",
                       backing_fmt->value.s);
J
Jes Sorensen 已提交
5281 5282 5283 5284 5285 5286
            goto out;
        }
    }

    // The size for the image must always be specified, with one exception:
    // If we are using a backing file, we can obtain the size from there
K
Kevin Wolf 已提交
5287 5288
    size = get_option_parameter(param, BLOCK_OPT_SIZE);
    if (size && size->value.n == -1) {
J
Jes Sorensen 已提交
5289
        if (backing_file && backing_file->value.s) {
5290
            BlockDriverState *bs;
J
Jes Sorensen 已提交
5291 5292
            uint64_t size;
            char buf[32];
5293 5294 5295 5296 5297
            int back_flags;

            /* backing files always opened read-only */
            back_flags =
                flags & ~(BDRV_O_RDWR | BDRV_O_SNAPSHOT | BDRV_O_NO_BACKING);
J
Jes Sorensen 已提交
5298

5299
            bs = NULL;
5300
            ret = bdrv_open(&bs, backing_file->value.s, NULL, NULL, back_flags,
5301
                            backing_drv, &local_err);
J
Jes Sorensen 已提交
5302
            if (ret < 0) {
5303 5304 5305 5306 5307
                error_setg_errno(errp, -ret, "Could not open '%s': %s",
                                 backing_file->value.s,
                                 error_get_pretty(local_err));
                error_free(local_err);
                local_err = NULL;
J
Jes Sorensen 已提交
5308 5309 5310 5311 5312 5313 5314
                goto out;
            }
            bdrv_get_geometry(bs, &size);
            size *= 512;

            snprintf(buf, sizeof(buf), "%" PRId64, size);
            set_option_parameter(param, BLOCK_OPT_SIZE, buf);
5315 5316

            bdrv_unref(bs);
J
Jes Sorensen 已提交
5317
        } else {
5318
            error_setg(errp, "Image creation needs a size parameter");
J
Jes Sorensen 已提交
5319 5320 5321 5322
            goto out;
        }
    }

5323 5324 5325 5326 5327
    if (!quiet) {
        printf("Formatting '%s', fmt=%s ", filename, fmt);
        print_option_parameters(param);
        puts("");
    }
5328 5329 5330 5331 5332 5333 5334 5335
    ret = bdrv_create(drv, filename, param, &local_err);
    if (ret == -EFBIG) {
        /* This is generally a better message than whatever the driver would
         * deliver (especially because of the cluster_size_hint), since that
         * is most probably not much different from "image too large". */
        const char *cluster_size_hint = "";
        if (get_option_parameter(create_options, BLOCK_OPT_CLUSTER_SIZE)) {
            cluster_size_hint = " (try using a larger cluster size)";
J
Jes Sorensen 已提交
5336
        }
5337 5338 5339 5340
        error_setg(errp, "The image size is too large for file format '%s'"
                   "%s", fmt, cluster_size_hint);
        error_free(local_err);
        local_err = NULL;
J
Jes Sorensen 已提交
5341 5342 5343 5344 5345 5346
    }

out:
    free_option_parameters(create_options);
    free_option_parameters(param);

5347
    if (local_err) {
5348 5349
        error_propagate(errp, local_err);
    }
J
Jes Sorensen 已提交
5350
}
5351 5352 5353 5354 5355 5356

AioContext *bdrv_get_aio_context(BlockDriverState *bs)
{
    /* Currently BlockDriverState always uses the main loop AioContext */
    return qemu_get_aio_context();
}
5357 5358 5359 5360 5361 5362

void bdrv_add_before_write_notifier(BlockDriverState *bs,
                                    NotifierWithReturn *notifier)
{
    notifier_with_return_list_add(&bs->before_write_notifiers, notifier);
}
M
Max Reitz 已提交
5363 5364 5365 5366 5367 5368 5369 5370

int bdrv_amend_options(BlockDriverState *bs, QEMUOptionParameter *options)
{
    if (bs->drv->bdrv_amend_options == NULL) {
        return -ENOTSUP;
    }
    return bs->drv->bdrv_amend_options(bs, options);
}
5371

5372 5373 5374 5375 5376
/* Used to recurse on single child block filters.
 * Single child block filter will store their child in bs->file.
 */
bool bdrv_generic_is_first_non_filter(BlockDriverState *bs,
                                      BlockDriverState *candidate)
5377
{
5378 5379 5380 5381 5382 5383 5384 5385 5386 5387 5388 5389 5390 5391
    if (!bs->drv) {
        return false;
    }

    if (!bs->drv->authorizations[BS_IS_A_FILTER]) {
        if (bs == candidate) {
            return true;
        } else {
            return false;
        }
    }

    if (!bs->drv->authorizations[BS_FILTER_PASS_DOWN]) {
        return false;
5392 5393
    }

5394 5395 5396 5397 5398 5399 5400 5401 5402 5403 5404 5405
    if (!bs->file) {
        return false;
    }

    return bdrv_recurse_is_first_non_filter(bs->file, candidate);
}

bool bdrv_recurse_is_first_non_filter(BlockDriverState *bs,
                                      BlockDriverState *candidate)
{
    if (bs->drv && bs->drv->bdrv_recurse_is_first_non_filter) {
        return bs->drv->bdrv_recurse_is_first_non_filter(bs, candidate);
5406 5407
    }

5408
    return bdrv_generic_is_first_non_filter(bs, candidate);
5409 5410
}

5411 5412 5413 5414 5415
/* This function checks if the candidate is the first non filter bs down it's
 * bs chain. Since we don't have pointers to parents it explore all bs chains
 * from the top. Some filters can choose not to pass down the recursion.
 */
bool bdrv_is_first_non_filter(BlockDriverState *candidate)
5416
{
5417 5418 5419 5420 5421 5422
    BlockDriverState *bs;

    /* walk down the bs forest recursively */
    QTAILQ_FOREACH(bs, &bdrv_states, device_list) {
        bool perm;

5423
        perm = bdrv_recurse_is_first_non_filter(bs, candidate);
5424 5425 5426 5427 5428 5429 5430 5431

        /* candidate is the first non filter */
        if (perm) {
            return true;
        }
    }

    return false;
5432
}