Re: [locking bug] inotify: inconsistent {RECLAIM_FS-ON-W} ->{IN-RECLAIM_FS-W} usage.

From: Andrew Morton
Date: Wed Feb 18 2009 - 17:27:18 EST


On Mon, 16 Feb 2009 09:13:04 +0100
Ingo Molnar <mingo@xxxxxxx> wrote:

> --- a/fs/notify/inotify/inotify.c
> +++ b/fs/notify/inotify/inotify.c
> @@ -156,7 +156,7 @@ static int inotify_handle_get_wd(struct inotify_handle *ih,
> int ret;
>
> do {
> - if (unlikely(!idr_pre_get(&ih->idr, GFP_KERNEL)))
> + if (unlikely(!idr_pre_get(&ih->idr, GFP_NOFS)))

Geeze the IDR interface sucks.

> return -ENOSPC;

Well that doesn't make a lot of sense.

> ret = idr_get_new_above(&ih->idr, watch, ih->last_wd+1, &watch->wd);
> } while (ret == -EAGAIN);

And afacit that can't happen. We hold the lock, so if idr_pre_get()
succeeded, idr_get_new_above() will not return -EAGAIN (which should
have been -ENOMEM).

I'd better stop looking.

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