From cf93980e775b709ec8f33f55846e6dcf1c7a612c Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Fri, 30 Aug 2013 14:34:26 +0200 Subject: [PATCH] qcow2: Employ metadata overlap checks The pre-write overlap check function is now called before most of the qcow2 writes (aborting it on collision or other error). Signed-off-by: Max Reitz Signed-off-by: Kevin Wolf --- block/qcow2-cache.c | 17 +++++++++++++++++ block/qcow2-cluster.c | 21 +++++++++++++++++++++ block/qcow2-snapshot.c | 22 ++++++++++++++++++++++ block/qcow2.c | 26 ++++++++++++++++++++++++++ 4 files changed, 86 insertions(+) diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c index 2f3114ecc2..7bcae09a69 100644 --- a/block/qcow2-cache.c +++ b/block/qcow2-cache.c @@ -114,6 +114,23 @@ static int qcow2_cache_entry_flush(BlockDriverState *bs, Qcow2Cache *c, int i) return ret; } + if (c == s->refcount_block_cache) { + ret = qcow2_pre_write_overlap_check(bs, + QCOW2_OL_DEFAULT & ~QCOW2_OL_REFCOUNT_BLOCK, + c->entries[i].offset, s->cluster_size); + } else if (c == s->l2_table_cache) { + ret = qcow2_pre_write_overlap_check(bs, + QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L2, + c->entries[i].offset, s->cluster_size); + } else { + ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, + c->entries[i].offset, s->cluster_size); + } + + if (ret < 0) { + return ret; + } + if (c == s->refcount_block_cache) { BLKDBG_EVENT(bs->file, BLKDBG_REFBLOCK_UPDATE_PART); } else if (c == s->l2_table_cache) { diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index cca76d4fcd..7c248aaede 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -80,6 +80,14 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, goto fail; } + /* the L1 position has not yet been updated, so these clusters must + * indeed be completely free */ + ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, + new_l1_table_offset, new_l1_size2); + if (ret < 0) { + goto fail; + } + BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_WRITE_TABLE); for(i = 0; i < s->l1_size; i++) new_l1_table[i] = cpu_to_be64(new_l1_table[i]); @@ -149,6 +157,13 @@ static int write_l1_entry(BlockDriverState *bs, int l1_index) buf[i] = cpu_to_be64(s->l1_table[l1_start_index + i]); } + ret = qcow2_pre_write_overlap_check(bs, + QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L1, + s->l1_table_offset + 8 * l1_start_index, sizeof(buf)); + if (ret < 0) { + return ret; + } + BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset + 8 * l1_start_index, buf, sizeof(buf)); @@ -368,6 +383,12 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs, &s->aes_encrypt_key); } + ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, + cluster_offset + n_start * BDRV_SECTOR_SIZE, n * BDRV_SECTOR_SIZE); + if (ret < 0) { + goto out; + } + BLKDBG_EVENT(bs->file, BLKDBG_COW_WRITE); ret = bdrv_co_writev(bs->file, (cluster_offset >> 9) + n_start, n, &qiov); if (ret < 0) { diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 0caac9055f..e7e601301a 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -189,6 +189,15 @@ static int qcow2_write_snapshots(BlockDriverState *bs) return ret; } + /* The snapshot list position has not yet been updated, so these clusters + * must indeed be completely free */ + ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset, + s->snapshots_size); + if (ret < 0) { + return ret; + } + + /* Write all snapshots to the new list */ for(i = 0; i < s->nb_snapshots; i++) { sn = s->snapshots + i; @@ -363,6 +372,12 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info) l1_table[i] = cpu_to_be64(s->l1_table[i]); } + ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, + sn->l1_table_offset, s->l1_size * sizeof(uint64_t)); + if (ret < 0) { + goto fail; + } + ret = bdrv_pwrite(bs->file, sn->l1_table_offset, l1_table, s->l1_size * sizeof(uint64_t)); if (ret < 0) { @@ -475,6 +490,13 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id) goto fail; } + ret = qcow2_pre_write_overlap_check(bs, + QCOW2_OL_DEFAULT & ~QCOW2_OL_ACTIVE_L1, + s->l1_table_offset, cur_l1_bytes); + if (ret < 0) { + goto fail; + } + ret = bdrv_pwrite_sync(bs->file, s->l1_table_offset, sn_l1_table, cur_l1_bytes); if (ret < 0) { diff --git a/block/qcow2.c b/block/qcow2.c index fe915681b2..05e002d856 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -624,6 +624,8 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags) qcow2_free_snapshots(bs); qcow2_refcount_close(bs); g_free(s->l1_table); + /* else pre-write overlap checks in cache_destroy may crash */ + s->l1_table = NULL; if (s->l2_table_cache) { qcow2_cache_destroy(bs, s->l2_table_cache); } @@ -923,6 +925,13 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs, cur_nr_sectors * 512); } + ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, + cluster_offset + index_in_cluster * BDRV_SECTOR_SIZE, + cur_nr_sectors * BDRV_SECTOR_SIZE); + if (ret < 0) { + goto fail; + } + qemu_co_mutex_unlock(&s->lock); BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); trace_qcow2_writev_data(qemu_coroutine_self(), @@ -989,6 +998,8 @@ static void qcow2_close(BlockDriverState *bs) { BDRVQcowState *s = bs->opaque; g_free(s->l1_table); + /* else pre-write overlap checks in cache_destroy may crash */ + s->l1_table = NULL; qcow2_cache_flush(bs, s->l2_table_cache); qcow2_cache_flush(bs, s->refcount_block_cache); @@ -1668,6 +1679,14 @@ static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, if (ret != Z_STREAM_END || out_len >= s->cluster_size) { /* could not compress: write normal cluster */ + + ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, + sector_num * BDRV_SECTOR_SIZE, + s->cluster_sectors * BDRV_SECTOR_SIZE); + if (ret < 0) { + goto fail; + } + ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); if (ret < 0) { goto fail; @@ -1680,6 +1699,13 @@ static int qcow2_write_compressed(BlockDriverState *bs, int64_t sector_num, goto fail; } cluster_offset &= s->cluster_offset_mask; + + ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, + cluster_offset, out_len); + if (ret < 0) { + goto fail; + } + BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len); if (ret < 0) {