Commit 7ea2d269 authored by Alexey Kardashevskiy's avatar Alexey Kardashevskiy Committed by Juan Quintela
Browse files

block/migration: Disable cache invalidate for incoming migration 



When migrated using libvirt with "--copy-storage-all", at the end of
migration there is race between NBD mirroring task trying to do flush
and migration completion, both end up invalidating cache. Since qcow2
driver does not handle this situation very well, random crashes happen.

This disables the BDRV_O_INCOMING flag for the block device being migrated
once the cache has been invalidated.

Signed-off-by: default avatarAlexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>

--

fixed parens by hand
Signed-off-by: default avatarJuan Quintela <quintela@redhat.com>
parent 9935baca

block.c

+5 −13
Original line number Diff line number Diff line
@@ -5043,6 +5043,11 @@ void bdrv_invalidate_cache(BlockDriverState *bs, Error **errp) 
        return;

    }



    if (!(bs->open_flags & BDRV_O_INCOMING)) {

        return;

    }

    bs->open_flags &= ~BDRV_O_INCOMING;



    if (bs->drv->bdrv_invalidate_cache) {

        bs->drv->bdrv_invalidate_cache(bs, &local_err);

    } else if (bs->file) {
@@ -5078,19 +5083,6 @@ void bdrv_invalidate_cache_all(Error **errp) 
    }

}



void bdrv_clear_incoming_migration_all(void)

{

    BlockDriverState *bs;



    QTAILQ_FOREACH(bs, &bdrv_states, device_list) {

        AioContext *aio_context = bdrv_get_aio_context(bs);



        aio_context_acquire(aio_context);

        bs->open_flags = bs->open_flags & ~(BDRV_O_INCOMING);

        aio_context_release(aio_context);

    }

}



int bdrv_flush(BlockDriverState *bs)

{

    Coroutine *co;

migration.c

+0 −1
Original line number Diff line number Diff line
@@ -103,7 +103,6 @@ static void process_incoming_migration_co(void *opaque) 
    }

    qemu_announce_self();



    bdrv_clear_incoming_migration_all();

    /* Make sure all file formats flush their mutable metadata */

    bdrv_invalidate_cache_all(&local_err);

    if (local_err) {

nbd.c

+6 −0
Original line number Diff line number Diff line
@@ -972,6 +972,12 @@ NBDExport *nbd_export_new(BlockDriverState *bs, off_t dev_offset, 
    exp->ctx = bdrv_get_aio_context(bs);

    bdrv_ref(bs);

    bdrv_add_aio_context_notifier(bs, bs_aio_attached, bs_aio_detach, exp);

    /*

     * NBD exports are used for non-shared storage migration.  Make sure

     * that BDRV_O_INCOMING is cleared and the image is ready for write

     * access since the export could be available before migration handover.

     */

    bdrv_invalidate_cache(bs, NULL);

    return exp;

}