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From: "Denis V. Lunev" <den@virtuozzo.com>
To: Mike Maslenkin <mike.maslenkin@gmail.com>,
	"Denis V. Lunev" <den@openvz.org>
Cc: qemu-block@nongnu.org, qemu-devel@nongnu.org,
	stefanha@redhat.com, alexander.ivanov@virtuozzo.com
Subject: Re: [PATCH 06/21] parallels: refactor path when we need to re-check image in parallels_open
Date: Sun, 17 Sep 2023 15:04:07 +0200	[thread overview]
Message-ID: <0e76c79a-670c-a7a6-c4a6-db69168858bf@virtuozzo.com> (raw)
In-Reply-To: <CAL77WPB7nRaWzzkQDqOJCQLpvWYd-=RpBiFn2Roi5wKzZONPFQ@mail.gmail.com>

On 9/17/23 13:40, Mike Maslenkin wrote:
> This patch generates a warning.
>
> On Fri, Sep 15, 2023 at 9:41 PM Denis V. Lunev <den@openvz.org> wrote:
>> More conditions follows thus the check should be more scalable.
>>
>> Signed-off-by: Denis V. Lunev <den@openvz.org>
>> ---
>>   block/parallels.c | 19 ++++++++-----------
>>   1 file changed, 8 insertions(+), 11 deletions(-)
>>
>> diff --git a/block/parallels.c b/block/parallels.c
>> index 8f223bfd89..aa29df9f77 100644
>> --- a/block/parallels.c
>> +++ b/block/parallels.c
>> @@ -1065,7 +1065,7 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
>>       int ret, size, i;
>>       int64_t file_nb_sectors, sector;
>>       uint32_t data_start;
>> -    bool data_off_is_correct;
>> +    bool need_check = false;
>>
>>       ret = parallels_opts_prealloc(bs, options, errp);
>>       if (ret < 0) {
>> @@ -1133,11 +1133,12 @@ static int parallels_open(BlockDriverState *bs, QDict *options, int flags,
>>       s->bat_bitmap = (uint32_t *)(s->header + 1);
>>
>>       if (le32_to_cpu(ph.inuse) == HEADER_INUSE_MAGIC) {
>> -        s->header_unclean = true;
>> +        need_check = s->header_unclean = true;
>>       }
>>
>> -    data_off_is_correct = parallels_test_data_off(s, file_nb_sectors,
>> -                                                  &data_start);
>> +    need_check = need_check ||
>> +                 !parallels_test_data_off(s, file_nb_sectors, &data_start);
>> +
> ../block/parallels.c:1139:18: warning: variable 'data_start' is used
> uninitialized whenever '||' condition is true
> [-Wsometimes-uninitialized]
>      need_check = need_check ||
>                   ^~~~~~~~~~
> ../block/parallels.c:1142:21: note: uninitialized use occurs here
>      s->data_start = data_start;
>                      ^~~~~~~~~~
> ../block/parallels.c:1139:18: note: remove the '||' if its condition
> is always false
>      need_check = need_check ||
>                   ^~~~~~~~~~~~~
> ../block/parallels.c:1067:24: note: initialize the variable
> 'data_start' to silence this warning
>      uint32_t data_start;
>                         ^
>                          = 0
> 1 warning generated.
>
>
> Regards,
> Mike.
wow! That is pretty much correct!

What compiler/OS you are using :)

Den


  reply	other threads:[~2023-09-17 13:05 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-15 18:41 [PATCH 00/21] implement discard operation for Parallels images Denis V. Lunev
2023-09-15 18:41 ` [PATCH 01/21] parallels: fix formatting in bdrv_parallels initialization Denis V. Lunev
2023-09-18  7:41   ` Alexander Ivanov
2023-09-18  7:42   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 02/21] parallels: mark driver as supporting CBT Denis V. Lunev
2023-09-18  7:43   ` Alexander Ivanov
2023-09-15 18:41 ` Denis V. Lunev
2023-09-15 18:41 ` [PATCH 03/21] parallels: invent parallels_opts_prealloc() helper to parse prealloc opts Denis V. Lunev
2023-09-17 11:40   ` Mike Maslenkin
2023-09-17 13:06     ` Denis V. Lunev
2023-09-18 15:21   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 04/21] parallels: return earler in fail_format branch in parallels_open() Denis V. Lunev
2023-09-18  8:14   ` Alexander Ivanov
2023-09-18  8:16     ` Alexander Ivanov
2023-09-18  8:17     ` Denis V. Lunev
2023-09-18  8:15   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 05/21] parallels: return earlier from parallels_open() function on error Denis V. Lunev
2023-09-18  8:17   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 06/21] parallels: refactor path when we need to re-check image in parallels_open Denis V. Lunev
2023-09-17 11:40   ` Mike Maslenkin
2023-09-17 13:04     ` Denis V. Lunev [this message]
2023-09-18  8:31   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 07/21] parallels: create mark_used() helper which sets bit in used bitmap Denis V. Lunev
2023-09-18  8:46   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 08/21] tests: ensure that image validation will not cure the corruption Denis V. Lunev
2023-09-18  9:03   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 09/21] parallels: fix broken parallels_check_data_off() Denis V. Lunev
2023-09-18  9:11   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 10/21] parallels: add test which will validate data_off fixes through repair Denis V. Lunev
2023-09-18  9:18   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 11/21] parallels: collect bitmap of used clusters at open Denis V. Lunev
2023-09-18 11:36   ` Alexander Ivanov
2023-09-15 18:41 ` Denis V. Lunev
2023-09-15 18:41 ` [PATCH 12/21] tests: fix broken deduplication check in parallels format test Denis V. Lunev
2023-09-18 11:43   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 13/21] tests: test self-cure of parallels image with duplicated clusters Denis V. Lunev
2023-09-18 11:51   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 14/21] parallels: accept multiple clusters in mark_used() Denis V. Lunev
2023-09-18 11:53   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 15/21] parallels: update used bitmap in allocate_cluster Denis V. Lunev
2023-09-18 11:58   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 16/21] parallels: naive implementation of allocate_clusters with used bitmap Denis V. Lunev
2023-09-18 13:09   ` Alexander Ivanov
2023-09-18 13:14     ` Denis V. Lunev
2023-09-18 13:18       ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 17/21] parallels: improve readability of allocate_clusters Denis V. Lunev
2023-09-18 13:15   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 18/21] parallels: naive implementation of parallels_co_pdiscard Denis V. Lunev
2023-09-17 11:40   ` Mike Maslenkin
2023-09-18 13:57   ` Alexander Ivanov
2023-09-18 14:05     ` Denis V. Lunev
2023-09-15 18:41 ` [PATCH 19/21] tests: extend test 131 to cover availability of the discard operation Denis V. Lunev
2023-09-18 15:09   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 20/21] parallels: naive implementation of parallels_co_pwrite_zeroes Denis V. Lunev
2023-09-18 15:10   ` Alexander Ivanov
2023-09-15 18:41 ` [PATCH 21/21] tests: extend test 131 to cover availability of the write-zeroes Denis V. Lunev
2023-09-18 15:17   ` Alexander Ivanov

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