On Mon, May 26, 2008 at 12:05:06AM -0700, Andrew Morton wrote: > It's purportedly showing that fdatasync() on ext3 is syncing the whole > world in fsync()-fashion even with an application which does not grow > the file size. > > But fdatasync() shouldn't do that. Even if the inode is dirty from > atime or mtime updates, that shouldn't cause fdatasync() to run an > ext3 commit? Well, ideally it shouldn't, although POSIX allows fdatasync() to be implemented in terms of fsync(). It is at the moment. :-/ The problem is we don't currently have a way of distinguishing between a "smudged" inode (only the mtime/atime has changed) and a "dirty" inode (even if the number of blocks hasn't changed, if i_size has changed, or i_mode, or anything else, including extended attributes inline in the inode). We're not tracking that difference. If we only allow mtime/atime changes through setattr (see Cristoph's patches), and don't set the VFS dirty bit, but our own "smudged" bit, we could do it --- but at the moment, we're not. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
