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qcow2: Handle failure for potentially large allocations

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Some code in the block layer makes potentially huge allocations. Failure
is not completely unexpected there, so avoid aborting qemu and handle
out-of-memory situations gracefully.

This patch addresses the allocations in the qcow2 block driver.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Kevin Wolf 2014-05-20 17:12:47 +02:00
parent 0df93305f2
commit de82815db1
5 changed files with 130 additions and 32 deletions
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36
block/qcow2-cluster.c
View file

@ -72,14 +72,20 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
#endif
new_l1_size2 = sizeof(uint64_t) * new_l1_size;
new_l1_table = g_malloc0(align_offset(new_l1_size2, 512));
new_l1_table = qemu_try_blockalign(bs->file,
align_offset(new_l1_size2, 512));
if (new_l1_table == NULL) {
return -ENOMEM;
}
memset(new_l1_table, 0, align_offset(new_l1_size2, 512));
memcpy(new_l1_table, s->l1_table, s->l1_size * sizeof(uint64_t));
/* write new table (align to cluster) */
BLKDBG_EVENT(bs->file, BLKDBG_L1_GROW_ALLOC_TABLE);
new_l1_table_offset = qcow2_alloc_clusters(bs, new_l1_size2);
if (new_l1_table_offset < 0) {
g_free(new_l1_table);
qemu_vfree(new_l1_table);
return new_l1_table_offset;
}
@ -113,7 +119,7 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
if (ret < 0) {
goto fail;
}
g_free(s->l1_table);
qemu_vfree(s->l1_table);
old_l1_table_offset = s->l1_table_offset;
s->l1_table_offset = new_l1_table_offset;
s->l1_table = new_l1_table;
@ -123,7 +129,7 @@ int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
QCOW2_DISCARD_OTHER);
return 0;
fail:
g_free(new_l1_table);
qemu_vfree(new_l1_table);
qcow2_free_clusters(bs, new_l1_table_offset, new_l1_size2,
QCOW2_DISCARD_OTHER);
return ret;
@ -372,7 +378,10 @@ static int coroutine_fn copy_sectors(BlockDriverState *bs,
}
iov.iov_len = n * BDRV_SECTOR_SIZE;
iov.iov_base = qemu_blockalign(bs, iov.iov_len);
iov.iov_base = qemu_try_blockalign(bs, iov.iov_len);
if (iov.iov_base == NULL) {
return -ENOMEM;
}
qemu_iovec_init_external(&qiov, &iov, 1);
@ -702,7 +711,11 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m)
trace_qcow2_cluster_link_l2(qemu_coroutine_self(), m->nb_clusters);
assert(m->nb_clusters > 0);
old_cluster = g_malloc(m->nb_clusters * sizeof(uint64_t));
old_cluster = g_try_malloc(m->nb_clusters * sizeof(uint64_t));
if (old_cluster == NULL) {
ret = -ENOMEM;
goto err;
}
/* copy content of unmodified sectors */
ret = perform_cow(bs, m, &m->cow_start);
@ -1562,7 +1575,10 @@ static int expand_zero_clusters_in_l1(BlockDriverState *bs, uint64_t *l1_table,
if (!is_active_l1) {
/* inactive L2 tables require a buffer to be stored in when loading
* them from disk */
l2_table = qemu_blockalign(bs, s->cluster_size);
l2_table = qemu_try_blockalign(bs->file, s->cluster_size);
if (l2_table == NULL) {
return -ENOMEM;
}
}
for (i = 0; i < l1_size; i++) {
@ -1740,7 +1756,11 @@ int qcow2_expand_zero_clusters(BlockDriverState *bs)
nb_clusters = size_to_clusters(s, bs->file->total_sectors *
BDRV_SECTOR_SIZE);
expanded_clusters = g_malloc0((nb_clusters + 7) / 8);
expanded_clusters = g_try_malloc0((nb_clusters + 7) / 8);
if (expanded_clusters == NULL) {
ret = -ENOMEM;
goto fail;
}
ret = expand_zero_clusters_in_l1(bs, s->l1_table, s->l1_size,
&expanded_clusters, &nb_clusters);