On Fri, Sep 07, 2007 at 01:28:55PM +0530, Bharata B Rao wrote: > On Fri, Sep 07, 2007 at 04:31:26PM +0900, hooanon05@xxxxxxxxxxx wrote: > > > > When the first readdir is issued: > > - call vfs_readdir for every underlying opened dir (file) object. > > - store every entry to either the hash table for the result or the > > whiteout, when the same-named entry didn't exist in the tables. > > - to improvement the performance, the allocated memory for the hash > > tables are managed in a pointer array. and the elements are > > concatinated logically by the pointer. > > - the pointer for the result-table, the version, and the currect jiffies > > are set to vdir, which is a cache in an inode. > > - all cache are copied to a member in a file object. > > - the index of the cache memory block and the offset in an array is > > handled as the seek position. > > Ok, interesting approach. So you define the seek behaviour on your > directory cache rather than allowing the underlying filesystems to > interpret the seek. I guess we can do something similar with Union > Mounts also. Unless I missunderstood something, Unionfs uses the same approach. Even Unionfs's ODF branch does the same thing. The major difference is that we keep the cache in a file on a disk. Josef 'Jeff' Sipek. -- Evolution, n.: A hypothetical process whereby infinitely improbable events occur with alarming frequency, order arises from chaos, and no one is given credit. - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
