On Wed, 20 July 2005 20:48:17 +0200, Jan Blunck wrote: > > I don't want to tell where these are in general, I need an easy way to > seek to the m'th directory + offset position without reading every > single dirent. With i_sizes != 0 it is straight forward to use "the sum > of the m directory's i_sizes + offset" as the f_pos to seek to. For this > purpose it is not necessary to have a "honest" i_size as long as the > i_size is bigger than the offset of the last dirent in the directory.
So you use file->offset of the pseudo-directory representing the whole union stack for two values: 1. level within the union stack we're currently at and 2. offset within the real directory at said level. And you need a sane value for i_size at every level (but perhaps the last) to break the converged file->offset apart into (level, offset) again. Right? > >>Reopening the same directory may result in a formerly proper offset > >>isn't anymore. > > Which is a user problem again. Might be that you are opening a different > directory with the same name ... or even a regular file! Yep. Two consecutive open() on the "same file" are racy, so anything could have happened in between. That's a well-known proplem in userspace. Jörn -- Linux is more the core point of a concept that surrounds "open source" which, in turn, is based on a false concept. This concept is that people actually want to look at source code. -- Rob Enderle - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
