Re: symlinks and NWFS

From: Alexander Viro (
Date: Fri May 12 2000 - 12:18:23 EST

On Fri, 12 May 2000, Jeff V. Merkey wrote:

> I guess the real question here is how much serialization does the VFS
> provide above you. I discovered last year in my initial forays with
> Linux that parallelism is fully exposed to the file system. The locks

->i_sem ->i_zombie
yes no lookup()
yes yes readdir(),create(),mknod(),mkdir(),symlink()
yes yes directory where create a link on link()
yes yes directory where we remove a link on unlink()
yes yes directory where we remove a link on rmdir()
yes yes both parents on rename()
no yes victim on rmdir()
no yes target of rename() if it exists and is a directory

> In the case of directories, the locks protect the block count. If the
> VFS above provides serialization for changes to directory data, this
> lock can be dropped.

        If you are interested in the contents - yes, all operations
that change directory contents grab ->i_zombie on that directory. See the
table above - your guarantees are there.

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