Testing for fcntl locks before doing ftruncate()?

[Jeremy Allison]

On Thu, Jan 19, 2006 at 01:53:34PM +0100, Volker Lendecke wrote:
> Hi!
> 
> A customer of mine is testing cross-platform access to files from Samba and
> Unix, in particular fcntl locking. One thing that happened that an 
> 
> echo hello > test.txt
> 
> done from a windows command window wiped out the file contents that had been
> locked by fcntl locks on the unix side. This happened because in open.c:
> 
>         if (flags2&O_TRUNC) {
>                 /*
>                  * We are modifing the file after open - update the stat
>                  * struct..
>                  */
>                 if ((SMB_VFS_FTRUNCATE(fsp,fsp->fh->fd,0) == -1) ||
>                     (SMB_VFS_FSTAT(fsp,fsp->fh->fd,psbuf)==-1)) {
>                         unlock_share_entry_fsp(fsp);
>                         fd_close(conn,fsp);
>                         file_free(fsp);
>                         return NULL;
>                 }
>         }
> 
> we don't check for byte range locks. Similarly for the ftruncate in smbwrite.
> 
> This is probably not what is expected. Shall we add some is_posix_locked()
> here?

No, we need a is_locked(), not a posix specific one I think. I'll take
a look.

Jeremy.