Btree directories (Re: Status of HFS+ support)

[Alexander Viro]

On Thu, 31 Aug 2000 flar at allandria.com wrote:

> Yes, HFS and HFS+ both have a CNID for each file or directory. It just isn't
> entirely straightforward to search the catalog by this value, since the key
> is a combination of parentCNID and name. The CNID is guaranteed to be unique
> across a filesystem and there are a handful that are reserved for system
> files/directories such as the root (2) and the "parent of root" (1).

OK. Are they preserved by rename()?

> > 	Directories are essentially the same as they used to be in 2.2,
> > except that handling of rmdir'ed busy directories is handled in VFS, so
> > you don't have to worry about them - if rmdir() or rename() over directory
> > return 0, directory is marked dead and you can forget about anything
> > except the ->lookup() on it - every other method will be stopped.
>
> What exactly is marked dead? The inode? I'm not really sure where this
> saves in actual code. Any place in particular to compare between 2.2 and 2.4?

You don't have to check that directory is not busy in rmdir()/rename().
Back in 2.2 filesystems either had to do that, or they had to detect
attempts to read/create in/etc. dead directories. Not much of a save,
but...


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