From: Denis Kirjanov <dkirjanov@suse.de>
To: Max Gautier <mg@max.gautier.name>,
Ratheesh Kannoth <rkannoth@marvell.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [EXTERNAL] Re: [PATCH iproute2-next v2] arpd: create /var/lib/arpd on first use
Date: Mon, 18 Mar 2024 12:37:47 +0300 [thread overview]
Message-ID: <e34a10c2-0901-4fe2-b984-5acca572af6a@suse.de> (raw)
In-Reply-To: <ZfgI2Aow6751-EGj@framework>
On 3/18/24 12:26, Max Gautier wrote:
> On Mon, Mar 18, 2024 at 09:18:59AM +0000, Ratheesh Kannoth wrote:
>>>>>>> + if (strcmp(default_dbname, dbname) == 0
>>>>>>> + && mkdir(ARPDDIR, 0755) != 0
>>>>>>> + && errno != EEXIST
>>>>>> why do you need errno != EEXIST case ? mkdir() will return error
>>>>>> in this case
>>>>> as well.
>>>>>
>>>>> EEXIST is not an error in this case: if the default location already
>>>>> exist, all is good. mkdir would still return -1 in this case, so we
>>>>> need to exclude it manually.
>>>>
>>>> ACK. IMO, it would make a more readable code if you consider splitting the
>>> "if" loop.
>>>
>>> Something like this ? I tend to pack conditions unless branching is necessary,
>>> but no problem if this form is preferred.
>>>
>>> if (strcmp(default_dbname, dbname) == 0) {
>>> if (mkdir(ARPDDIR, 0755) != 0 && errno != EEXIST) {
>>> ...
>>> }
>>> }
>> ACK.
>> instead of errno != EXIST , you may consider stat() before mkdir() call. Just my way thinking(please ignore it, if you don't like).
>> My thinking is --> you need to execute mkdir () only first time, second time onwards, stat() call will return 0.
>
> That's racy: we can stat and have a non existing folder, then have
> another arpd instance (or anything else, really) create the directory,
Agreed ^^
> and we would hit EEXIST anyway when we call mkdir.
> Also, that needs two syscalls instead of one.
>
next prev parent reply other threads:[~2024-03-18 9:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20240313093856.17fc459e@hermes.local>
2024-03-16 9:06 ` [PATCH iproute2-next] arpd: create /var/lib/arpd on first use Max Gautier
2024-03-16 15:07 ` Stephen Hemminger
2024-03-16 19:56 ` Jay Vosburgh
2024-03-17 0:14 ` Max Gautier
2024-03-17 9:01 ` [PATCH iproute2-next v2] " Max Gautier
2024-03-17 15:39 ` Stephen Hemminger
[not found] ` <09BB339D-A57C-4F67-BE67-2859F0262C86@126.com>
2024-03-17 17:23 ` Max Gautier
2024-03-18 2:56 ` Ratheesh Kannoth
2024-03-18 8:37 ` Max Gautier
2024-03-18 8:51 ` [EXTERNAL] " Ratheesh Kannoth
2024-03-18 8:59 ` Max Gautier
2024-03-18 9:18 ` Ratheesh Kannoth
2024-03-18 9:26 ` Max Gautier
2024-03-18 9:37 ` Denis Kirjanov [this message]
2024-03-18 9:43 ` Ratheesh Kannoth
2024-03-18 15:49 ` [PATCH iproute2-next v3] " Max Gautier
2024-03-28 20:40 ` patchwork-bot+netdevbpf
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