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Re: [Qemu-devel] [PATCH v2 1/1] block: improve error handling in raw_ope
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] [PATCH v2 1/1] block: improve error handling in raw_open |
Date: |
Tue, 26 Jul 2016 19:54:13 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 |
On 26.07.2016 19:18, Halil Pasic wrote:
>
>
> On 07/26/2016 05:42 PM, Max Reitz wrote:
>>> +++ b/block/raw-posix.c
>>>> @@ -485,6 +485,7 @@ static int raw_open_common(BlockDriverState *bs, QDict
>>>> *options,
>>>> s->fd = -1;
>>>> fd = qemu_open(filename, s->open_flags, 0644);
>>>> if (fd < 0) {
>>>> + error_setg_errno(errp, errno, "Could not open file");
>> We don't guarantee that error_setg_errno() does not modify errno. (In
>> practice it should not, but we don't guarantee that.)
>>
>
>
> Thank you very much for your review. I have double checked, and I
> remembered correctly: error_setg_errno saves and restores the original
> errno, so that is why I assumed it does not.
Oh, and about this: Yes, I remember, this was introduced after we had
noticed that we had some old code that assumed that error_setg() would
not modify errno. We had to decide between making error_setg*() save and
restore errno (which we deemed a bit ugly) and fixing all of that old
code (which we deemed hard). So we want for the former, but I don't
think we actually guarantee that behavior (because you should never rely
on any function not to modify errno).
(The difference between us saving/restoring errno in practice and
guaranteeing that feature is the lack of documentation thereof, i.e.,
the comment for error_setg() in include/qapi/error.h doesn't mention
this :-))
Max
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- Re: [Qemu-devel] [Qemu-block] [PATCH 1/1] block: improve error handling in raw_open, (continued)
[Qemu-devel] [PATCH v2 1/1] block: improve error handling in raw_open, Halil Pasic, 2016/07/26
Re: [Qemu-devel] [PATCH v2 1/1] block: improve error handling in raw_open,
Max Reitz <=
Re: [Qemu-devel] [PATCH v2 1/1] block: improve error handling in raw_open, Markus Armbruster, 2016/07/27
Re: [Qemu-devel] [PATCH v2 1/1] block: improve error handling in raw_open, Sascha Silbe, 2016/07/26
Re: [Qemu-devel] [PATCH v2 1/1] block: improve error handling in raw_open, Max Reitz, 2016/07/26
Re: [Qemu-devel] [PATCH v2 1/1] block: improve error handling in raw_open, Sascha Silbe, 2016/07/26
Re: [Qemu-devel] [Qemu-block] [PATCH v2 1/1] block: improve error handling in raw_open, John Snow, 2016/07/26
[Qemu-devel] [PATCH 1/1] block: improve error handling in raw_open, Halil Pasic, 2016/07/27