Commit 71b58b82 authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Kevin Wolf
Browse files

qemu-io: add write -z option for bdrv_co_write_zeroes 



Extend the qemu-io write command with the -z option to call
bdrv_co_write_zeroes().  Exposing the zero write interface from qemu-io
allows us to write tests that exercise this new block layer interface.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 0e71be19

qemu-io.c

+69 −8
Original line number Diff line number Diff line
@@ -218,6 +218,51 @@ static int do_pwrite(char *buf, int64_t offset, int count, int *total) 
    return 1;

}



typedef struct {

    int64_t offset;

    int count;

    int *total;

    int ret;

    bool done;

} CoWriteZeroes;



static void coroutine_fn co_write_zeroes_entry(void *opaque)

{

    CoWriteZeroes *data = opaque;



    data->ret = bdrv_co_write_zeroes(bs, data->offset / BDRV_SECTOR_SIZE,

                                     data->count / BDRV_SECTOR_SIZE);

    data->done = true;

    if (data->ret < 0) {

        *data->total = data->ret;

        return;

    }



    *data->total = data->count;

}



static int do_co_write_zeroes(int64_t offset, int count, int *total)

{

    Coroutine *co;

    CoWriteZeroes data = {

        .offset = offset,

        .count  = count,

        .total  = total,

        .done   = false,

    };



    co = qemu_coroutine_create(co_write_zeroes_entry);

    qemu_coroutine_enter(co, &data);

    while (!data.done) {

        qemu_aio_wait();

    }

    if (data.ret < 0) {

        return data.ret;

    } else {

        return 1;

    }

}



static int do_load_vmstate(char *buf, int64_t offset, int count, int *total)

{

    *total = bdrv_load_vmstate(bs, (uint8_t *)buf, offset, count);
@@ -643,6 +688,7 @@ static void write_help(void) 
" -P, -- use different pattern to fill file\n"

" -C, -- report statistics in a machine parsable format\n"

" -q, -- quiet mode, do not show I/O statistics\n"

" -z, -- write zeroes using bdrv_co_write_zeroes\n"

"\n");

}
@@ -654,7 +700,7 @@ static const cmdinfo_t write_cmd = { 
    .cfunc      = write_f,

    .argmin     = 2,

    .argmax     = -1,

    .args       = "[-abCpq] [-P pattern ] off len",

    .args       = "[-bCpqz] [-P pattern ] off len",

    .oneline    = "writes a number of bytes at a specified offset",

    .help       = write_help,

};
@@ -662,16 +708,16 @@ static const cmdinfo_t write_cmd = { 
static int write_f(int argc, char **argv)

{

    struct timeval t1, t2;

    int Cflag = 0, pflag = 0, qflag = 0, bflag = 0;

    int Cflag = 0, pflag = 0, qflag = 0, bflag = 0, Pflag = 0, zflag = 0;

    int c, cnt;

    char *buf;

    char *buf = NULL;

    int64_t offset;

    int count;

    /* Some compilers get confused and warn if this is not initialized.  */

    int total = 0;

    int pattern = 0xcd;



    while ((c = getopt(argc, argv, "bCpP:q")) != EOF) {

    while ((c = getopt(argc, argv, "bCpP:qz")) != EOF) {

        switch (c) {

        case 'b':

            bflag = 1;
@@ -683,6 +729,7 @@ static int write_f(int argc, char **argv) 
            pflag = 1;

            break;

        case 'P':

            Pflag = 1;

            pattern = parse_pattern(optarg);

            if (pattern < 0) {

                return 0;
@@ -691,6 +738,9 @@ static int write_f(int argc, char **argv) 
        case 'q':

            qflag = 1;

            break;

        case 'z':

            zflag = 1;

            break;

        default:

            return command_usage(&write_cmd);

        }
@@ -700,8 +750,13 @@ static int write_f(int argc, char **argv) 
        return command_usage(&write_cmd);

    }



    if (bflag && pflag) {

        printf("-b and -p cannot be specified at the same time\n");

    if (bflag + pflag + zflag > 1) {

        printf("-b, -p, or -z cannot be specified at the same time\n");

        return 0;

    }



    if (zflag && Pflag) {

        printf("-z and -P cannot be specified at the same time\n");

        return 0;

    }
@@ -732,13 +787,17 @@ static int write_f(int argc, char **argv) 
        }

    }



    if (!zflag) {

        buf = qemu_io_alloc(count, pattern);

    }



    gettimeofday(&t1, NULL);

    if (pflag) {

        cnt = do_pwrite(buf, offset, count, &total);

    } else if (bflag) {

        cnt = do_save_vmstate(buf, offset, count, &total);

    } else if (zflag) {

        cnt = do_co_write_zeroes(offset, count, &total);

    } else {

        cnt = do_write(buf, offset, count, &total);

    }
@@ -758,7 +817,9 @@ static int write_f(int argc, char **argv) 
    print_report("wrote", &t2, offset, count, total, cnt, Cflag);



out:

    if (!zflag) {

        qemu_io_free(buf);

    }



    return 0;

}