Re: COW fs (Re: Editing-in-place of a large file)

Pavel Machek (
Fri, 14 Sep 2001 10:03:51 +0000


> - Keep a hash of the contents of blocks in the buffer-cache.
> - The kernel compares the hash of each block write to all blocks already
> in the buffer-cache.
> - If a duplicate is found, the kernel generates a COW link instead of
> writing the block to disk.
> Obviously this would involve large amounts of CPU. I think a simple

Why? If you hashed the hashes, you could do it very fast.

Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt,
details at

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to More majordomo info at Please read the FAQ at