Re: [RFC] pdirops: vfs patch

[Jan Blunck]

Quoting Alex Tomas <alex@xxxxxxxxxxxxx>:

> >>>>> Jan Blunck (JB) writes:
>
>  >> 1) i_sem protects dcache too
>
>  JB> Where? i_sem is the per-inode lock, and shouldn't be used else.
>
> read comments in fs/namei.c:read_lookup()
>

i_sem does NOT protect the dcache. Also not in real_lookup(). The lock must be
acquired for ->lookup() and because we might sleep on i_sem, we have to get it
early and check for repopulation of the dcache.

> we've already done this for ext3. it works.
> it speeds some loads up significantly.
> especially on big directories.
> and you can control this via mount option,
> so almost zero cost for fs that doesn't support pdirops.

Ok.

Jan
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