Re: [PATCH v4] flock.2: add CIFS details
From: Pavel Shilovsky <hidden>
Date: 2021-03-16 23:05:10
Also in:
linux-cifs, linux-fsdevel
Make sense to make it simpler. Then I would just propose a minor fix - to remove "even" on the last line because IO from the same file descriptor is allowed. """ Another important side-effect is that the locks are not advisory anymore: any IO on a locked file will always fail with EACCES, when done from a separate file descriptor. """ -- Best regards, Pavel Shilovsky вт, 16 мар. 2021 г. в 12:42, Tom Talpey [off-list ref]:
On 3/16/2021 1:39 PM, Pavel Shilovsky wrote:quoted
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.quoted
-- 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 GPG: 1839 CB5F 9F5B FB9B AA97 8C99 03C8 A49B 521B D5D3 SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg, DE GF: Felix Imendörffer, Mary Higgins, Sri Rasiah HRB 247165 (AG München)