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block/qcow2-bitmap: fix and improve qcow2_reopen_bitmaps_rw

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- Correct check for write access to file child, and in correct place
  (only if we want to write).
- Support reopen rw -> rw (which will be used in following commit),
  for example, !bdrv_dirty_bitmap_readonly() is not a corruption if
  bitmap is marked IN_USE in the image.
- Consider unexpected bitmap as a corruption and check other
  combinations of in-image and in-RAM bitmaps.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20190927122355.7344-9-vsementsov@virtuozzo.com
Signed-off-by: John Snow <jsnow@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2019-09-27 15:23:54 +03:00 committed by John Snow
parent 5d9388d4b2
commit f6333cbf8b
1 changed files with 58 additions and 19 deletions
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77
block/qcow2-bitmap.c
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@ -1108,18 +1108,14 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
Qcow2BitmapList *bm_list;
Qcow2Bitmap *bm;
GSList *ro_dirty_bitmaps = NULL;
int ret = 0;
int ret = -EINVAL;
bool need_header_update = false;
if (s->nb_bitmaps == 0) {
/* No bitmaps - nothing to do */
return 0;
}
if (!can_write(bs)) {
error_setg(errp, "Can't write to the image on reopening bitmaps rw");
return -EINVAL;
}
bm_list = bitmap_list_load(bs, s->bitmap_directory_offset,
s->bitmap_directory_size, errp);
if (bm_list == NULL) {
@ -1128,32 +1124,75 @@ int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp)
QSIMPLEQ_FOREACH(bm, bm_list, entry) {
BdrvDirtyBitmap *bitmap = bdrv_find_dirty_bitmap(bs, bm->name);
if (bitmap == NULL) {
continue;
}
if (!bdrv_dirty_bitmap_readonly(bitmap)) {
error_setg(errp, "Bitmap %s was loaded prior to rw-reopen, but was "
"not marked as readonly. This is a bug, something went "
"wrong. All of the bitmaps may be corrupted", bm->name);
ret = -EINVAL;
if (!bitmap) {
error_setg(errp, "Unexpected bitmap '%s' in image '%s'",
bm->name, bs->filename);
goto out;
}
bm->flags |= BME_FLAG_IN_USE;
ro_dirty_bitmaps = g_slist_append(ro_dirty_bitmaps, bitmap);
if (!(bm->flags & BME_FLAG_IN_USE)) {
if (!bdrv_dirty_bitmap_readonly(bitmap)) {
error_setg(errp, "Corruption: bitmap '%s' is not marked IN_USE "
"in the image '%s' and not marked readonly in RAM",
bm->name, bs->filename);
goto out;
}
if (bdrv_dirty_bitmap_inconsistent(bitmap)) {
error_setg(errp, "Corruption: bitmap '%s' is inconsistent but "
"is not marked IN_USE in the image '%s'", bm->name,
bs->filename);
goto out;
}
bm->flags |= BME_FLAG_IN_USE;
need_header_update = true;
} else {
/*
* What if flags already has BME_FLAG_IN_USE ?
*
* 1. if we are reopening RW -> RW it's OK, of course.
* 2. if we are reopening RO -> RW:
* 2.1 if @bitmap is inconsistent, it's OK. It means that it was
* inconsistent (IN_USE) when we loaded it
* 2.2 if @bitmap is not inconsistent. This seems to be impossible
* and implies third party interaction. Let's error-out for
* safety.
*/
if (bdrv_dirty_bitmap_readonly(bitmap) &&
!bdrv_dirty_bitmap_inconsistent(bitmap))
{
error_setg(errp, "Corruption: bitmap '%s' is marked IN_USE "
"in the image '%s' but it is readonly and "
"consistent in RAM",
bm->name, bs->filename);
goto out;
}
}
if (bdrv_dirty_bitmap_readonly(bitmap)) {
ro_dirty_bitmaps = g_slist_append(ro_dirty_bitmaps, bitmap);
}
}
if (ro_dirty_bitmaps != NULL) {
if (need_header_update) {
if (!can_write(bs->file->bs) || !(bs->file->perm & BLK_PERM_WRITE)) {
error_setg(errp, "Failed to reopen bitmaps rw: no write access "
"the protocol file");
goto out;
}
/* in_use flags must be updated */
ret = update_ext_header_and_dir_in_place(bs, bm_list);
if (ret < 0) {
error_setg_errno(errp, -ret, "Can't update bitmap directory");
error_setg_errno(errp, -ret, "Cannot update bitmap directory");
goto out;
}
g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, false);
}
g_slist_foreach(ro_dirty_bitmaps, set_readonly_helper, false);
ret = 0;
out:
g_slist_free(ro_dirty_bitmaps);
bitmap_list_free(bm_list);