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qcow1: 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 qcow1 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 13:36:05 +02:00
parent f7b593d937
commit 0df93305f2
1 changed files with 26 additions and 7 deletions
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33
block/qcow.c
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@ -182,7 +182,12 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
}
s->l1_table_offset = header.l1_table_offset;
s->l1_table = g_malloc(s->l1_size * sizeof(uint64_t));
s->l1_table = g_try_malloc(s->l1_size * sizeof(uint64_t));
if (s->l1_table == NULL) {
error_setg(errp, "Could not allocate memory for L1 table");
ret = -ENOMEM;
goto fail;
}
ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
s->l1_size * sizeof(uint64_t));
@ -193,8 +198,16 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
for(i = 0;i < s->l1_size; i++) {
be64_to_cpus(&s->l1_table[i]);
}
/* alloc L2 cache */
s->l2_cache = g_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
/* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
s->l2_cache =
qemu_try_blockalign(bs->file,
s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
if (s->l2_cache == NULL) {
error_setg(errp, "Could not allocate L2 table cache");
ret = -ENOMEM;
goto fail;
}
s->cluster_cache = g_malloc(s->cluster_size);
s->cluster_data = g_malloc(s->cluster_size);
s->cluster_cache_offset = -1;
@ -226,7 +239,7 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
fail:
g_free(s->l1_table);
g_free(s->l2_cache);
qemu_vfree(s->l2_cache);
g_free(s->cluster_cache);
g_free(s->cluster_data);
return ret;
@ -517,7 +530,10 @@ static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
void *orig_buf;
if (qiov->niov > 1) {
buf = orig_buf = qemu_blockalign(bs, qiov->size);
buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
if (buf == NULL) {
return -ENOMEM;
}
} else {
orig_buf = NULL;
buf = (uint8_t *)qiov->iov->iov_base;
@ -619,7 +635,10 @@ static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
s->cluster_cache_offset = -1; /* disable compressed cache */
if (qiov->niov > 1) {
buf = orig_buf = qemu_blockalign(bs, qiov->size);
buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
if (buf == NULL) {
return -ENOMEM;
}
qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
} else {
orig_buf = NULL;
@ -685,7 +704,7 @@ static void qcow_close(BlockDriverState *bs)
BDRVQcowState *s = bs->opaque;
g_free(s->l1_table);
g_free(s->l2_cache);
qemu_vfree(s->l2_cache);
g_free(s->cluster_cache);
g_free(s->cluster_data);