From mboxrd@z Thu Jan 1 00:00:00 1970 In-reply-to: <45DC8A47.5050900@redhat.com> (message from Peter Staubach on Wed, 21 Feb 2007 13:07:03 -0500) Subject: Re: [PATCH] update ctime and mtime for mmaped write References: <45DC8A47.5050900@redhat.com> Message-Id: From: Miklos Szeredi Date: Wed, 21 Feb 2007 19:23:29 +0100 Sender: owner-linux-mm@kvack.org Return-Path: To: staubach@redhat.com Cc: akpm@linux-foundation.org, hugh@veritas.com, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: > > Inspired by Peter Staubach's patch and the resulting comments. > > > > > > An updated version of the original patch was submitted to LKML > yesterday... :-) Strange coincidence :) > > file = vma->vm_file; > > start = vma->vm_end; > > + mapping_update_time(file); > > if ((flags & MS_SYNC) && file && > > (vma->vm_flags & VM_SHARED)) { > > get_file(file); > > > > It seems to me that this might lead to file times being updated for > non-MAP_SHARED mappings. In theory no, because the COW-ed pages become anonymous and are not part of the original mapping any more. > > +int set_page_dirty_mapping(struct page *page); > > > > This aspect of the design seems intrusive to me. I didn't see a strong > reason to introduce new versions of many of the routines just to handle > these semantics. What motivated this part of your design? Why the new > _mapping versions of routines? Because there's no way to know inside the set_page_dirty() functions if the dirtying comes from a memory mapping or from a modification through a normal write(). And they have different semantics, for write() the modification times are updated immediately. Thanks, Miklos -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org