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authorKevin Wolf <kwolf@redhat.com>2014-05-20 17:12:47 +0200
committerKevin Wolf <kwolf@redhat.com>2014-08-15 15:07:15 +0200
commitde82815db1c89da058b7fb941dab137d6d9ab738 (patch)
tree782b541f1a0c5d154d2c8a166306e7407094bf9a
parent0df93305f21712e975ab5df260cc5a91e5daafca (diff)
qcow2: Handle failure for potentially large allocations
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>
-rw-r--r--block/qcow2-cache.c13
-rw-r--r--block/qcow2-cluster.c36
-rw-r--r--block/qcow2-refcount.c48
-rw-r--r--block/qcow2-snapshot.c23
-rw-r--r--block/qcow2.c42
5 files changed, 130 insertions, 32 deletions
diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c
index 8ecbb5bc00..5353b44828 100644
--- a/block/qcow2-cache.c
+++ b/block/qcow2-cache.c
@@ -53,10 +53,21 @@ Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables)
c->entries = g_malloc0(sizeof(*c->entries) * num_tables);
for (i = 0; i < c->size; i++) {
- c->entries[i].table = qemu_blockalign(bs, s->cluster_size);
+ c->entries[i].table = qemu_try_blockalign(bs->file, s->cluster_size);
+ if (c->entries[i].table == NULL) {
+ goto fail;
+ }
}
return c;
+
+fail:
+ for (i = 0; i < c->size; i++) {
+ qemu_vfree(c->entries[i].table);
+ }
+ g_free(c->entries);
+ g_free(c);
+ return NULL;
}
int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 4208dc08b5..e7c5f486cd 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -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);
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index cc6cf743d6..87a56d84af 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -46,8 +46,12 @@ int qcow2_refcount_init(BlockDriverState *bs)
assert(s->refcount_table_size <= INT_MAX / sizeof(uint64_t));
refcount_table_size2 = s->refcount_table_size * sizeof(uint64_t);
- s->refcount_table = g_malloc(refcount_table_size2);
+ s->refcount_table = g_try_malloc(refcount_table_size2);
+
if (s->refcount_table_size > 0) {
+ if (s->refcount_table == NULL) {
+ goto fail;
+ }
BLKDBG_EVENT(bs->file, BLKDBG_REFTABLE_LOAD);
ret = bdrv_pread(bs->file, s->refcount_table_offset,
s->refcount_table, refcount_table_size2);
@@ -344,8 +348,14 @@ static int alloc_refcount_block(BlockDriverState *bs,
uint64_t meta_offset = (blocks_used * refcount_block_clusters) *
s->cluster_size;
uint64_t table_offset = meta_offset + blocks_clusters * s->cluster_size;
- uint16_t *new_blocks = g_malloc0(blocks_clusters * s->cluster_size);
- uint64_t *new_table = g_malloc0(table_size * sizeof(uint64_t));
+ uint64_t *new_table = g_try_malloc0(table_size * sizeof(uint64_t));
+ uint16_t *new_blocks = g_try_malloc0(blocks_clusters * s->cluster_size);
+
+ assert(table_size > 0 && blocks_clusters > 0);
+ if (new_table == NULL || new_blocks == NULL) {
+ ret = -ENOMEM;
+ goto fail_table;
+ }
/* Fill the new refcount table */
memcpy(new_table, s->refcount_table,
@@ -424,6 +434,7 @@ static int alloc_refcount_block(BlockDriverState *bs,
return -EAGAIN;
fail_table:
+ g_free(new_blocks);
g_free(new_table);
fail_block:
if (*refcount_block != NULL) {
@@ -847,7 +858,8 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
int64_t l1_table_offset, int l1_size, int addend)
{
BDRVQcowState *s = bs->opaque;
- uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2, l1_allocated;
+ uint64_t *l1_table, *l2_table, l2_offset, offset, l1_size2;
+ bool l1_allocated = false;
int64_t old_offset, old_l2_offset;
int i, j, l1_modified = 0, nb_csectors, refcount;
int ret;
@@ -862,8 +874,12 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
* l1_table_offset when it is the current s->l1_table_offset! Be careful
* when changing this! */
if (l1_table_offset != s->l1_table_offset) {
- l1_table = g_malloc0(align_offset(l1_size2, 512));
- l1_allocated = 1;
+ l1_table = g_try_malloc0(align_offset(l1_size2, 512));
+ if (l1_size2 && l1_table == NULL) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+ l1_allocated = true;
ret = bdrv_pread(bs->file, l1_table_offset, l1_table, l1_size2);
if (ret < 0) {
@@ -875,7 +891,7 @@ int qcow2_update_snapshot_refcount(BlockDriverState *bs,
} else {
assert(l1_size == s->l1_size);
l1_table = s->l1_table;
- l1_allocated = 0;
+ l1_allocated = false;
}
for(i = 0; i < l1_size; i++) {
@@ -1197,7 +1213,11 @@ static int check_refcounts_l1(BlockDriverState *bs,
if (l1_size2 == 0) {
l1_table = NULL;
} else {
- l1_table = g_malloc(l1_size2);
+ l1_table = g_try_malloc(l1_size2);
+ if (l1_table == NULL) {
+ ret = -ENOMEM;
+ goto fail;
+ }
if (bdrv_pread(bs->file, l1_table_offset,
l1_table, l1_size2) != l1_size2)
goto fail;
@@ -1501,7 +1521,11 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
return -EFBIG;
}
- refcount_table = g_malloc0(nb_clusters * sizeof(uint16_t));
+ refcount_table = g_try_malloc0(nb_clusters * sizeof(uint16_t));
+ if (nb_clusters && refcount_table == NULL) {
+ res->check_errors++;
+ return -ENOMEM;
+ }
res->bfi.total_clusters =
size_to_clusters(s, bs->total_sectors * BDRV_SECTOR_SIZE);
@@ -1753,9 +1777,13 @@ int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset,
uint64_t l1_ofs = s->snapshots[i].l1_table_offset;
uint32_t l1_sz = s->snapshots[i].l1_size;
uint64_t l1_sz2 = l1_sz * sizeof(uint64_t);
- uint64_t *l1 = g_malloc(l1_sz2);
+ uint64_t *l1 = g_try_malloc(l1_sz2);
int ret;
+ if (l1_sz2 && l1 == NULL) {
+ return -ENOMEM;
+ }
+
ret = bdrv_pread(bs->file, l1_ofs, l1, l1_sz2);
if (ret < 0) {
g_free(l1);
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 0aa9defbe2..f67b47282f 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -381,7 +381,12 @@ int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
sn->l1_table_offset = l1_table_offset;
sn->l1_size = s->l1_size;
- l1_table = g_malloc(s->l1_size * sizeof(uint64_t));
+ l1_table = g_try_malloc(s->l1_size * sizeof(uint64_t));
+ if (s->l1_size && l1_table == NULL) {
+ ret = -ENOMEM;
+ goto fail;
+ }
+
for(i = 0; i < s->l1_size; i++) {
l1_table[i] = cpu_to_be64(s->l1_table[i]);
}
@@ -499,7 +504,11 @@ int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id)
* Decrease the refcount referenced by the old one only when the L1
* table is overwritten.
*/
- sn_l1_table = g_malloc0(cur_l1_bytes);
+ sn_l1_table = g_try_malloc0(cur_l1_bytes);
+ if (cur_l1_bytes && sn_l1_table == NULL) {
+ ret = -ENOMEM;
+ goto fail;
+ }
ret = bdrv_pread(bs->file, sn->l1_table_offset, sn_l1_table, sn_l1_bytes);
if (ret < 0) {
@@ -698,17 +707,21 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs,
return -EFBIG;
}
new_l1_bytes = sn->l1_size * sizeof(uint64_t);
- new_l1_table = g_malloc0(align_offset(new_l1_bytes, 512));
+ new_l1_table = qemu_try_blockalign(bs->file,
+ align_offset(new_l1_bytes, 512));
+ if (new_l1_table == NULL) {
+ return -ENOMEM;
+ }
ret = bdrv_pread(bs->file, sn->l1_table_offset, new_l1_table, new_l1_bytes);
if (ret < 0) {
error_setg(errp, "Failed to read l1 table for snapshot");
- g_free(new_l1_table);
+ qemu_vfree(new_l1_table);
return ret;
}
/* Switch the L1 table */
- g_free(s->l1_table);
+ qemu_vfree(s->l1_table);
s->l1_size = sn->l1_size;
s->l1_table_offset = sn->l1_table_offset;
diff --git a/block/qcow2.c b/block/qcow2.c
index 964ab93b08..435e0e11d0 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -688,8 +688,13 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
if (s->l1_size > 0) {
- s->l1_table = g_malloc0(
+ s->l1_table = qemu_try_blockalign(bs->file,
align_offset(s->l1_size * sizeof(uint64_t), 512));
+ if (s->l1_table == NULL) {
+ error_setg(errp, "Could not allocate L1 table");
+ ret = -ENOMEM;
+ goto fail;
+ }
ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
s->l1_size * sizeof(uint64_t));
if (ret < 0) {
@@ -704,11 +709,22 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
/* alloc L2 table/refcount block cache */
s->l2_table_cache = qcow2_cache_create(bs, L2_CACHE_SIZE);
s->refcount_block_cache = qcow2_cache_create(bs, REFCOUNT_CACHE_SIZE);
+ if (s->l2_table_cache == NULL || s->refcount_block_cache == NULL) {
+ error_setg(errp, "Could not allocate metadata caches");
+ ret = -ENOMEM;
+ goto fail;
+ }
s->cluster_cache = g_malloc(s->cluster_size);
/* one more sector for decompressed data alignment */
- s->cluster_data = qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size
- + 512);
+ s->cluster_data = qemu_try_blockalign(bs->file, QCOW_MAX_CRYPT_CLUSTERS
+ * s->cluster_size + 512);
+ if (s->cluster_data == NULL) {
+ error_setg(errp, "Could not allocate temporary cluster buffer");
+ ret = -ENOMEM;
+ goto fail;
+ }
+
s->cluster_cache_offset = -1;
s->flags = flags;
@@ -852,7 +868,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,
cleanup_unknown_header_ext(bs);
qcow2_free_snapshots(bs);
qcow2_refcount_close(bs);
- g_free(s->l1_table);
+ qemu_vfree(s->l1_table);
/* else pre-write overlap checks in cache_destroy may crash */
s->l1_table = NULL;
if (s->l2_table_cache) {
@@ -1082,7 +1098,12 @@ static coroutine_fn int qcow2_co_readv(BlockDriverState *bs, int64_t sector_num,
*/
if (!cluster_data) {
cluster_data =
- qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size);
+ qemu_try_blockalign(bs->file, QCOW_MAX_CRYPT_CLUSTERS
+ * s->cluster_size);
+ if (cluster_data == NULL) {
+ ret = -ENOMEM;
+ goto fail;
+ }
}
assert(cur_nr_sectors <=
@@ -1182,8 +1203,13 @@ static coroutine_fn int qcow2_co_writev(BlockDriverState *bs,
if (s->crypt_method) {
if (!cluster_data) {
- cluster_data = qemu_blockalign(bs, QCOW_MAX_CRYPT_CLUSTERS *
- s->cluster_size);
+ cluster_data = qemu_try_blockalign(bs->file,
+ QCOW_MAX_CRYPT_CLUSTERS
+ * s->cluster_size);
+ if (cluster_data == NULL) {
+ ret = -ENOMEM;
+ goto fail;
+ }
}
assert(hd_qiov.size <=
@@ -1270,7 +1296,7 @@ fail:
static void qcow2_close(BlockDriverState *bs)
{
BDRVQcowState *s = bs->opaque;
- g_free(s->l1_table);
+ qemu_vfree(s->l1_table);
/* else pre-write overlap checks in cache_destroy may crash */
s->l1_table = NULL;