Re: [PATCH v4] flock.2: add CIFS details

On 3/16/2021 1:39 PM, Pavel Shilovsky wrote:

Sure. Thanks!

I would put more details from
https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-lockfileex
:

"""
   Another important side-effect is that the locks are not advisory anymore:
   any IO on an exclusively locked file will always fail with EACCES
   when done from a separate file descriptor; write calls on
   a file locked for shared access will fail with EACCES when done
   from any file descriptor including the one used to lock the file.
"""

Thoughts?

I think it'll be important to define what "exclusive" and "shared"
mean from a Linux/POSIX API perspective, and that will get into dragon
territory. I don't think it's a good idea to attempt that in this
manpage. It is best to leave Windows semantics, and interop with
Windows clients, out of it.

IOW, I personally prefer Aurélien's simple version for now.

Tom.

--
Best regards,
Pavel Shilovsky

вт, 16 мар. 2021 г. в 03:42, Aurélien Aptel [off-list ref]:

quoted

Pavel Shilovsky [off-list ref] writes:

quoted

It is not only about writing to a locked file. It is also about any IO
against a locked file if such a file is locked through another file
handle. Right?

Yes that was implied, the write was a simple example to illustrate. I'll
update to make it more generic:

   Another important side-effect is that the locks are not advisory anymore:
   any IO on a locked file will always fail with EACCES,
   even when done from a separate file descriptor.

If you have comments please provide direct text suggestion to save time.

Cheers,
--
Aurélien Aptel / SUSE Labs Samba Team
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