Valerie Henson wrote:
So what the heck are continuation inodes? Actually, we named this "chunkfs" - not particularly descriptive, maybe continuation inodes is a better term.
[...]
The basic idea is to create a bunch of small file systems - chunks - which look like one big file system to the administrator. Major
Back when I was still playing with my experimental filesystem, one of the short-list features I was planning on implementing was the allocation of both metadata and data from the same underlying data store, essentially collections of "buckets" for data.
The data store would be a succession of progressively-smaller buckets. Typical bucket sizes (chosen by admin) on a single filesystem might be: 1G, 128M, 4M, 1M, 64k, 4k. The largest (top-most) bucket is the fundamental unit of allocation for the filesystem, from which all other metadata and data is read/allocated.
So in my example above, the 1G bucket is analagous to a single chunk in chunkfs, and any number of 1G buckets -- from any number of block devices -- may comprise a single filesystem.
New inode tables, bitmap chunks, directories, large files, etc. are all allocated from an "appropriate" bucket. IMO this type of solution provides fsck-friendly isolation, and adds sufficient flexibility for doing things like delayed alloc, metadata-is-a-file, etc.
Jeff - 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
