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From: Tao Lyu <tao.lyu@epfl.ch>
To: "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Question about O_APPEND | O_DIRECT
Date: Thu, 23 Nov 2023 18:14:51 +0000	[thread overview]
Message-ID: <c609e5f9df75438dbfe3810859935d58@epfl.ch> (raw)

Hi,

Sorry to bother you here.

I'm using NFS and realize it doesn't support opening a file with "O_DIRECT | O_APPEND".

After checking the source code, 
I found it has one function that checks explicitly whether there is a combination flag of "O_APPEND | O_DIRECT".
If so, it will return invalid arguments.

int nfs_check_flags(int flags)
{
    if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
        return -EINVAL;

    return 0;
}

But I don't understand why NFS doesn't support this flag combination.
I'd appreciate it if someone could explain this to me.

Thanks in advance.

Best,
Tao



             reply	other threads:[~2023-11-23 18:21 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-23 18:14 Tao Lyu [this message]
2023-11-25 23:54 ` Question about O_APPEND | O_DIRECT Trond Myklebust
2023-11-27 15:28   ` Tao Lyu
2023-11-27 16:36     ` Christoph Hellwig
2023-11-27 16:41       ` Tao Lyu
2023-11-27 16:50       ` Chuck Lever III
2023-11-27 16:55         ` Christoph Hellwig
2023-11-27 16:59           ` Chuck Lever III
2023-11-28 13:06             ` Christoph Hellwig
2023-11-28  1:50         ` Rick Macklem
2023-11-28 13:09           ` Christoph Hellwig
2023-11-28 18:28             ` Trond Myklebust
2023-11-27 17:08       ` Trond Myklebust
2023-11-27 17:19         ` hch
2023-11-27 17:23           ` Tao Lyu

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