On Friday 25 January 2008, Theodore Tso wrote: > On Fri, Jan 25, 2008 at 01:55:37PM -0500, Chris Mason wrote: > > Since btrfs maintains both a name index and an inode index, I can > > iterate over the name index (hash values) for use cases that require > > telldir/seekdir. At any rate, there are a variety of choices for > > working around it, but I'm focusing on the disk format first ;) > > Well, there is a disk format way of handling the problem, and which is > what JFS used; it simply maintained associated a separate "telldir" > cookie for each file, and had separate b-tree which allowed for fast > access each file given its telldir cookie. btrfs could theoretically > do something similar. I'd suggest thinking about this as an optional > feature, which would be enabled if full 100% reliable telldir/seekdir > support is required, or for NFS servers. > > There are indeed workarounds, but unfortunately they all have > downsides.... >
Hmmm, for seekdir and telldir, my understanding was that I was allowed to return entries more than once, especially in the face of changes to the directory in between calls. http://www.opengroup.org/onlinepubs/000095399/functions/seekdir.html Does the JFS cookie allow you to get from the file to to the directory entry? We've got that now via backrefs. -chris _______________________________________________ Btrfs-devel mailing list [email protected] http://oss.oracle.com/mailman/listinfo/btrfs-devel
