diff options
| -rw-r--r-- | block/qcow2-snapshot.c | 7 | ||||
| -rw-r--r-- | block/qcow2.c | 5 | ||||
| -rw-r--r-- | block/qcow2.h | 5 |
3 files changed, 12 insertions, 5 deletions
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index e7e601301a..ffead08ca2 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -416,6 +416,13 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) g_free(old_snapshot_list); + /* The VM state isn't needed any more in the active L1 table; in fact, it + * hurts by causing expensive COW for the next snapshot. */ + qcow2_discard_clusters(bs, qcow2_vm_state_offset(s), + align_offset(sn->vm_state_size, s->cluster_size) + >> BDRV_SECTOR_BITS, + QCOW2_DISCARD_NEVER); + #ifdef DEBUG_ALLOC { BdrvCheckResult result = {0}; diff --git a/block/qcow2.c b/block/qcow2.c index 147822e8fd..c9e266e22e 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1757,11 +1757,6 @@ static coroutine_fn int qcow2_co_flush_to_os(BlockDriverState *bs) return 0; } -static int64_t qcow2_vm_state_offset(BDRVQcowState *s) -{ - return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits); -} - static int qcow2_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) { BDRVQcowState *s = bs->opaque; diff --git a/block/qcow2.h b/block/qcow2.h index 9c33b98457..49eed828c5 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -361,6 +361,11 @@ static inline int64_t align_offset(int64_t offset, int n) return offset; } +static inline int64_t qcow2_vm_state_offset(BDRVQcowState *s) +{ + return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits); +} + static inline int qcow2_get_cluster_type(uint64_t l2_entry) { if (l2_entry & QCOW_OFLAG_COMPRESSED) { |