On Wed, 2008-01-23 at 09:20 -0500, Jack Schmidt wrote:
On a linux system's CIFS mounted filesystem, it is not possible to rename a file opened read-write:
$ sleep 5 >> .subscriptions.lock & mv .subscriptions.lock .subscriptions mv: cannot move
.subscriptions.lock' to.subscriptions': Text file busy
Does this happen only if the file is opened by the same process, or also if it's opened by another process? Sounds like it happens no matter who has the file open.
The documentation for rename(2) indicates that it is allowed to return an error when the file is already opened,
I don't see it saying that in Debian unstable or in UNIX98 specs.
so perhaps the file should be closed before the replace. Should this be done in file_dotlock_replace (before line 672) generally?
This is a similar patch than I've previously suggested to people having similar NFS problems: http://dovecot.org/list/dovecot/2006-December/018145.html
But I don't really want to make it work like that as default. It most likely doesn't fix all the possible places in code where this can happen. Or if this same problem happens when another process has the file opened, this doesn't help with it either. So if someone is using a system where this is a problem, I'd rather have them patch this code themselves so they know that Dovecot may not always work correctly.