Commit 9eae9cca authored by Denis V. Lunev's avatar Denis V. Lunev Committed by Stefan Hajnoczi
Browse files

block/parallels: read parallels image header and BAT into single buffer 



This metadata cache would allow to properly batch BAT updates to disk
in next patches. These updates will be properly aligned to avoid
read-modify-write transactions on block level.

Signed-off-by: default avatarDenis V. Lunev <den@openvz.org>
Reviewed-by: default avatarRoman Kagan <rkagan@parallels.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarRoman Kagan <rkagan@parallels.com>
Message-id: 1430207220-24458-18-git-send-email-den@openvz.org
CC: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent dd97cdc0

block/parallels.c

+17 −7
Original line number Diff line number Diff line
@@ -61,6 +61,8 @@ typedef struct BDRVParallelsState { 
     */

    CoMutex lock;



    ParallelsHeader *header;

    uint32_t header_size;

    uint32_t *bat_bitmap;

    unsigned int bat_size;
@@ -91,7 +93,7 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags, 
{

    BDRVParallelsState *s = bs->opaque;

    ParallelsHeader ph;

    int ret;

    int ret, size;



    ret = bdrv_pread(bs->file, 0, &ph, sizeof(ph));

    if (ret < 0) {
@@ -130,17 +132,25 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags, 
        ret = -EFBIG;

        goto fail;

    }

    s->bat_bitmap = g_try_new(uint32_t, s->bat_size);

    if (s->bat_size && s->bat_bitmap == NULL) {



    size = sizeof(ParallelsHeader) + sizeof(uint32_t) * s->bat_size;

    s->header_size = ROUND_UP(size, bdrv_opt_mem_align(bs->file));

    s->header = qemu_try_blockalign(bs->file, s->header_size);

    if (s->header == NULL) {

        ret = -ENOMEM;

        goto fail;

    }

    if (le32_to_cpu(ph.data_off) < s->header_size) {

        /* there is not enough unused space to fit to block align between BAT

           and actual data. We can't avoid read-modify-write... */

        s->header_size = size;

    }



    ret = bdrv_pread(bs->file, sizeof(ParallelsHeader),

                     s->bat_bitmap, s->bat_size * sizeof(uint32_t));

    ret = bdrv_pread(bs->file, 0, s->header, s->header_size);

    if (ret < 0) {

        goto fail;

    }

    s->bat_bitmap = (uint32_t *)(s->header + 1);



    s->has_truncate = bdrv_has_zero_init(bs->file) &&

                      bdrv_truncate(bs->file, bdrv_getlength(bs->file)) == 0;
@@ -152,7 +162,7 @@ fail_format: 
    error_setg(errp, "Image not in Parallels format");

    ret = -EINVAL;

fail:

    g_free(s->bat_bitmap);

    qemu_vfree(s->header);

    return ret;

}
@@ -400,7 +410,7 @@ exit: 
static void parallels_close(BlockDriverState *bs)

{

    BDRVParallelsState *s = bs->opaque;

    g_free(s->bat_bitmap);

    qemu_vfree(s->header);

}



static QemuOptsList parallels_create_opts = {