Messages in this thread | | | Subject | Re: ctime set by truncate even if NOCMTIME requested | From | Trond Myklebust <> | Date | Mon, 19 Sep 2005 14:58:23 -0400 |
| |
må den 19.09.2005 Klokka 12:51 (-0500) skreiv Steve French: > I am seeing requests to set ctime on truncate which does not make any > sense to me as I was testing with the flag that should have turned that > off. ie my inodes having S_NOCMTIME set, as NFS does. > > do_truncate (line 206 of open.c) sets > newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME > instead of > newattrs.ia_valid = ATTR_SIZE; > if(!IS_NOCMTIME(inode)) > newattrs.ia_valid |= ATTR_CTIME; > > I thought that the correct way to handle this for network filesystems, > is to let the server set the mtime and ctime unless the application > explicitly sets the attributes (in the case of the sys call truncate or > ftruncate the application is not explicitly setting the ctime/mtime as > it would on a backup/restore so they should be ignored for the network > fs so the server will set it correctl to its time, reducing traffic and > more accurately representing the time it got updated). > > Shouldn't there be a IS_NOCMTIME check in the truncate path in fs/open.c?
See the discussion on this a couple of weeks back.
It is quite correct for the kernel to request that the filesystem set ctime/mtime on successful calls to open(O_TRUNC). http://www.opengroup.org/onlinepubs/009695399/toc.htm
It is _incorrect_ for it to request that ctime/mtime be set (or that the suid/sgid mode bit be cleared) if a truncate()/ftruncate() call results in no size change. http://www.opengroup.org/onlinepubs/009695399/toc.htm
So the current do_truncate() does have to be changed. Adding a check for IS_NOCMTIME would be wrong, though.
Cheers, Trond
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |