Commit f05fa4ad authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Kevin Wolf
Browse files

block: flush in writethrough mode after writes 



We want to make the formats handle their own flushes
autonomously, while keeping for guests the ability to use a writethrough
cache.  Since formats will write metadata via bs->file, bdrv_co_do_writev
is the only place where we need to add a flush.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 0fd05e8d

block.c

+9 −2
Original line number Diff line number Diff line
@@ -1758,8 +1758,8 @@ int bdrv_pwrite_sync(BlockDriverState *bs, int64_t offset, 
        return ret;

    }



    /* No flush needed for cache modes that use O_DSYNC */

    if ((bs->open_flags & BDRV_O_CACHE_WB) != 0) {

    /* No flush needed for cache modes that already do it */

    if (bs->enable_write_cache) {

        bdrv_flush(bs);

    }
@@ -1808,6 +1808,9 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BlockDriverState *bs, 
        ret = bdrv_co_do_write_zeroes(bs, cluster_sector_num,

                                      cluster_nb_sectors);

    } else {

        /* This does not change the data on the disk, it is not necessary

         * to flush even in cache=writethrough mode.

         */

        ret = drv->bdrv_co_writev(bs, cluster_sector_num, cluster_nb_sectors,

                                  &bounce_qiov);

    }
@@ -1977,6 +1980,10 @@ static int coroutine_fn bdrv_co_do_writev(BlockDriverState *bs, 
        ret = drv->bdrv_co_writev(bs, sector_num, nb_sectors, qiov);

    }



    if (ret == 0 && !bs->enable_write_cache) {

        ret = bdrv_co_flush(bs);

    }



    if (bs->dirty_bitmap) {

        set_dirty_bitmap(bs, sector_num, nb_sectors, 1);

    }