diff options
Diffstat (limited to 'block/qcow2-refcount.c')
| -rw-r--r-- | block/qcow2-refcount.c | 38 |
1 files changed, 27 insertions, 11 deletions
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index ac95b88fe..14b2f67f1 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -705,8 +705,15 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, BDRVQcowState *s = bs->opaque; uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated; int64_t old_offset, old_l2_offset; - int i, j, l1_modified, nb_csectors, refcount; + int i, j, l1_modified = 0, nb_csectors, refcount; int ret; + bool old_l2_writethrough, old_refcount_writethrough; + + /* Switch caches to writeback mode during update */ + old_l2_writethrough = + qcow2_cache_set_writethrough(bs, s->l2_table_cache, false); + old_refcount_writethrough = + qcow2_cache_set_writethrough(bs, s->refcount_block_cache, false); l2_table = NULL; l1_table = NULL; @@ -720,7 +727,11 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, l1_allocated = 1; if (bdrv_pread(bs->file, l1_table_offset, l1_table, l1_size2) != l1_size2) + { + ret = -EIO; goto fail; + } + for(i = 0;i < l1_size; i++) be64_to_cpus(&l1_table[i]); } else { @@ -729,7 +740,6 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, l1_allocated = 0; } - l1_modified = 0; for(i = 0; i < l1_size; i++) { l2_offset = l1_table[i]; if (l2_offset) { @@ -773,6 +783,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, } if (refcount < 0) { + ret = -EIO; goto fail; } } @@ -803,6 +814,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, refcount = get_refcount(bs, l2_offset >> s->cluster_bits); } if (refcount < 0) { + ret = -EIO; goto fail; } else if (refcount == 1) { l2_offset |= QCOW_OFLAG_COPIED; @@ -813,6 +825,18 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, } } } + + ret = 0; +fail: + if (l2_table) { + qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); + } + + /* Enable writethrough cache mode again */ + qcow2_cache_set_writethrough(bs, s->l2_table_cache, old_l2_writethrough); + qcow2_cache_set_writethrough(bs, s->refcount_block_cache, + old_refcount_writethrough); + if (l1_modified) { for(i = 0; i < l1_size; i++) cpu_to_be64s(&l1_table[i]); @@ -824,15 +848,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs, } if (l1_allocated) qemu_free(l1_table); - return 0; - fail: - if (l2_table) { - qcow2_cache_put(bs, s->l2_table_cache, (void**) &l2_table); - } - - if (l1_allocated) - qemu_free(l1_table); - return -EIO; + return ret; } |