Commit c2e001cc authored by Eric Blake's avatar Eric Blake Committed by Max Reitz
Browse files

qemu-io: Add 'write -z -u' to test MAY_UNMAP flag 



Make it easier to control whether the BDRV_REQ_MAY_UNMAP flag
can be passed through a write_zeroes command, by adding the '-u'
flag to qemu-io 'write -z' and 'aio_write -z'.  To be useful,
the device has to be opened with BDRV_O_UNMAP (done by default
in qemu-io, but can be made explicit with '-d unmap').

Signed-off-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarMax Reitz <mreitz@redhat.com>
Message-id: 1462677405-4752-7-git-send-email-eblake@redhat.com
Signed-off-by: default avatarMax Reitz <mreitz@redhat.com>
parent 770e0e0e

qemu-io-cmds.c

+21 −3
Original line number Diff line number Diff line
@@ -943,6 +943,7 @@ 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"

" -u, -- with -z, allow unmapping\n"

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

"\n");

}
@@ -955,7 +956,7 @@ static const cmdinfo_t write_cmd = { 
    .cfunc      = write_f,

    .argmin     = 2,

    .argmax     = -1,

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

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

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

    .help       = write_help,

};
@@ -974,7 +975,7 @@ static int write_f(BlockBackend *blk, int argc, char **argv) 
    int64_t total = 0;

    int pattern = 0xcd;



    while ((c = getopt(argc, argv, "bcCfpP:qz")) != -1) {

    while ((c = getopt(argc, argv, "bcCfpP:quz")) != -1) {

        switch (c) {

        case 'b':

            bflag = true;
@@ -1001,6 +1002,9 @@ static int write_f(BlockBackend *blk, int argc, char **argv) 
        case 'q':

            qflag = true;

            break;

        case 'u':

            flags |= BDRV_REQ_MAY_UNMAP;

            break;

        case 'z':

            zflag = true;

            break;
@@ -1023,6 +1027,11 @@ static int write_f(BlockBackend *blk, int argc, char **argv) 
        return 0;

    }



    if ((flags & BDRV_REQ_MAY_UNMAP) && !zflag) {

        printf("-u requires -z to be specified\n");

        return 0;

    }



    if (zflag && Pflag) {

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

        return 0;
@@ -1561,6 +1570,7 @@ static void aio_write_help(void) 
" -C, -- report statistics in a machine parsable format\n"

" -f, -- use Force Unit Access semantics\n"

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

" -u, -- with -z, allow unmapping\n"

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

"\n");

}
@@ -1572,7 +1582,7 @@ static const cmdinfo_t aio_write_cmd = { 
    .cfunc      = aio_write_f,

    .argmin     = 2,

    .argmax     = -1,

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

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

    .oneline    = "asynchronously writes a number of bytes",

    .help       = aio_write_help,

};
@@ -1596,6 +1606,9 @@ static int aio_write_f(BlockBackend *blk, int argc, char **argv) 
        case 'q':

            ctx->qflag = true;

            break;

        case 'u':

            flags |= BDRV_REQ_MAY_UNMAP;

            break;

        case 'P':

            pattern = parse_pattern(optarg);

            if (pattern < 0) {
@@ -1623,6 +1636,11 @@ static int aio_write_f(BlockBackend *blk, int argc, char **argv) 
        return 0;

    }



    if ((flags & BDRV_REQ_MAY_UNMAP) && !ctx->zflag) {

        printf("-u requires -z to be specified\n");

        return 0;

    }



    if (ctx->zflag && ctx->Pflag) {

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

        g_free(ctx);