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qcow2: Employ metadata overlap checks

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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 <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Max Reitz 2013-08-30 14:34:26 +02:00 • committed by Kevin Wolf
parent a40f1c2add
commit cf93980e77
4 changed files with 86 additions and 0 deletions
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26
block/qcow2.c
View file

@ -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) {