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qcow2: Handle QCowL2Meta on error in preallocate_co()

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If qcow2_alloc_cluster_offset() or qcow2_alloc_cluster_link_l2() fail
then this function simply returns the error code, potentially leaking
the QCowL2Meta structure and leaving stale items in s->cluster_allocs.

A second problem is that this function calls qcow2_free_any_clusters()
on failure but passing a host cluster offset instead of an L2 entry.
Luckily for normal uncompressed clusters a raw offset also works like
a valid L2 entry so it works just the same, but we should be using
qcow2_free_clusters() instead.

This patch fixes both problems by using qcow2_handle_l2meta().

Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-Id: <cd3a6b9abd43f9c0b60be413d760f0cacc67eb66.1599573989.git.berto@igalia.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
This commit is contained in:
Alberto Garcia 2020-09-08 16:08:27 +02:00 committed by Max Reitz
parent 83a6a90009
commit 1a52b73dba
1 changed files with 17 additions and 23 deletions
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40
block/qcow2.c
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@ -2101,7 +2101,6 @@ static coroutine_fn int qcow2_handle_l2meta(BlockDriverState *bs,
QCowL2Meta *next;
if (link_l2) {
assert(!l2meta->prealloc);
ret = qcow2_alloc_cluster_link_l2(bs, l2meta);
if (ret) {
goto out;
@ -3123,7 +3122,7 @@ static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset,
int64_t file_length;
unsigned int cur_bytes;
int ret;
QCowL2Meta *meta;
QCowL2Meta *meta = NULL, *m;
assert(offset <= new_length);
bytes = new_length - offset;
@ -3134,27 +3133,17 @@ static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset,
&host_offset, &meta);
if (ret < 0) {
error_setg_errno(errp, -ret, "Allocating clusters failed");
return ret;
goto out;
}
while (meta) {
QCowL2Meta *next = meta->next;
meta->prealloc = true;
for (m = meta; m != NULL; m = m->next) {
m->prealloc = true;
}
ret = qcow2_alloc_cluster_link_l2(bs, meta);
if (ret < 0) {
error_setg_errno(errp, -ret, "Mapping clusters failed");
qcow2_free_any_clusters(bs, meta->alloc_offset,
meta->nb_clusters, QCOW2_DISCARD_NEVER);
return ret;
}
/* There are no dependent requests, but we need to remove our
* request from the list of in-flight requests */
QLIST_REMOVE(meta, next_in_flight);
g_free(meta);
meta = next;
ret = qcow2_handle_l2meta(bs, &meta, true);
if (ret < 0) {
error_setg_errno(errp, -ret, "Mapping clusters failed");
goto out;
}
/* TODO Preallocate data if requested */
@ -3171,7 +3160,8 @@ static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset,
file_length = bdrv_getlength(s->data_file->bs);
if (file_length < 0) {
error_setg_errno(errp, -file_length, "Could not get file size");
return file_length;
ret = file_length;
goto out;
}
if (host_offset + cur_bytes > file_length) {
@ -3181,11 +3171,15 @@ static int coroutine_fn preallocate_co(BlockDriverState *bs, uint64_t offset,
ret = bdrv_co_truncate(s->data_file, host_offset + cur_bytes, false,
mode, 0, errp);
if (ret < 0) {
return ret;
goto out;
}
}
return 0;
ret = 0;
out:
qcow2_handle_l2meta(bs, &meta, false);
return ret;
}
/* qcow2_refcount_metadata_size: