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Re: [Qemu-devel] [PATCH v7 11/13] qcow2: Clean up after refcount rebuild
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH v7 11/13] qcow2: Clean up after refcount rebuild |
Date: |
Wed, 22 Oct 2014 11:19:38 +0200 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 22.10.2014 um 10:08 hat Max Reitz geschrieben:
> Because the old refcount structure will be leaked after having rebuilt
> it, we need to recalculate the refcounts and run a leak-fixing operation
> afterwards (if leaks should be fixed at all).
>
> Signed-off-by: Max Reitz <address@hidden>
> ---
> block/qcow2-refcount.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 45 insertions(+)
>
> diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
> index 8ca2324..b7c956c 100644
> --- a/block/qcow2-refcount.c
> +++ b/block/qcow2-refcount.c
> @@ -1962,12 +1962,57 @@ int qcow2_check_refcounts(BlockDriverState *bs,
> BdrvCheckResult *res,
> nb_clusters);
>
> if (rebuild && (fix & BDRV_FIX_ERRORS)) {
> + BdrvCheckResult old_res = *res;
> + int fresh_leaks = 0;
> +
> fprintf(stderr, "Rebuilding refcount structure\n");
> ret = rebuild_refcount_structure(bs, res, &refcount_table,
> &nb_clusters);
> if (ret < 0) {
> goto fail;
> }
> +
> + res->corruptions = 0;
> + res->leaks = 0;
> +
> + /* Because the old reftable has been exchanged for a new one the
> + * references have to be recalculated */
> + rebuild = false;
> + memset(refcount_table, 0, nb_clusters * sizeof(uint16_t));
> + ret = calculate_refcounts(bs, res, 0, &rebuild, &refcount_table,
> + &nb_clusters);
> + if (ret < 0) {
> + goto fail;
> + }
> +
> + if (fix & BDRV_FIX_LEAKS) {
> + /* The old refcount structures are now leaked, fix it; the result
> + * can be ignored, aside from leaks which were introduced by
> + * rebuild_refcount_structure() that could not be fixed */
> + BdrvCheckResult saved_res = *res;
> + *res = (BdrvCheckResult){ 0 };
> +
> + compare_refcounts(bs, res, BDRV_FIX_LEAKS, &rebuild,
> + &highest_cluster, refcount_table, nb_clusters);
> + if (rebuild) {
> + fprintf(stderr, "ERROR rebuilt refcount structure is still "
> + "broken\n");
> + }
> +
> + /* Any leaks accounted for here were introduced by
> + * rebuild_refcount_structure() because that function has
> created a
> + * new refcount structure from scratch */
> + fresh_leaks = res->leaks - res->leaks_fixed;
Fixed leaks are not accounted for in res->leaks, so you probably want to
use that directly without subtracting res->leaks_fixed.
> + *res = saved_res;
> + }
> +
> + if (res->corruptions < old_res.corruptions) {
> + res->corruptions_fixed += old_res.corruptions - res->corruptions;
> + }
> + if (res->leaks < old_res.leaks) {
> + res->leaks_fixed += old_res.leaks - res->leaks;
> + }
> + res->leaks += fresh_leaks;
> } else if (fix) {
> if (rebuild) {
> fprintf(stderr, "ERROR need to rebuild refcount structures\n");
Kevin
- [Qemu-devel] [PATCH v7 06/13] qcow2: Pull check_refblocks() up, (continued)
- [Qemu-devel] [PATCH v7 06/13] qcow2: Pull check_refblocks() up, Max Reitz, 2014/10/22
- [Qemu-devel] [PATCH v7 07/13] qcow2: Reuse refcount table in calculate_refcounts(), Max Reitz, 2014/10/22
- [Qemu-devel] [PATCH v7 08/13] qcow2: Fix refcount blocks beyond image end, Max Reitz, 2014/10/22
- [Qemu-devel] [PATCH v7 09/13] qcow2: Do not perform potentially damaging repairs, Max Reitz, 2014/10/22
- [Qemu-devel] [PATCH v7 10/13] qcow2: Rebuild refcount structure during check, Max Reitz, 2014/10/22
- [Qemu-devel] [PATCH v7 11/13] qcow2: Clean up after refcount rebuild, Max Reitz, 2014/10/22
- Re: [Qemu-devel] [PATCH v7 11/13] qcow2: Clean up after refcount rebuild,
Kevin Wolf <=
- [Qemu-devel] [PATCH v7 12/13] iotests: Fix test outputs, Max Reitz, 2014/10/22
- [Qemu-devel] [PATCH v7 13/13] iotests: Add test for potentially damaging repairs, Max Reitz, 2014/10/22