From: Christoph Hellwig <hch@infradead.org>
To: Felix Blyakher <felixb@sgi.com>
Cc: Hedi Berriche <hedi@sgi.com>, xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: prevent deadlock in xfs_qm_shake()
Date: Fri, 29 May 2009 15:25:29 -0400 [thread overview]
Message-ID: <20090529192529.GA1599@infradead.org> (raw)
In-Reply-To: <1243620631-10749-2-git-send-email-felixb@sgi.com>
On Fri, May 29, 2009 at 01:10:31PM -0500, Felix Blyakher wrote:
> It's possible to recurse into filesystem from the memory
> allocation, which deadlocks in xfs_qm_shake(). Add check
> for __GFP_FS, and bailout if it is not set.
>
> Signed-off-by: Felix Blyakher <felixb@sgi.com>
> Signed-off-by: Hedi Berriche <hedi@sgi.com>
> ---
> fs/xfs/linux-2.6/kmem.h | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/fs/xfs/linux-2.6/kmem.h b/fs/xfs/linux-2.6/kmem.h
> index af6843c..d8d2321 100644
> --- a/fs/xfs/linux-2.6/kmem.h
> +++ b/fs/xfs/linux-2.6/kmem.h
> @@ -103,7 +103,7 @@ extern void *kmem_zone_zalloc(kmem_zone_t *, unsigned int __nocast);
> static inline int
> kmem_shake_allow(gfp_t gfp_mask)
> {
> - return (gfp_mask & __GFP_WAIT) != 0;
> + return ((gfp_mask & __GFP_WAIT && gfp_mask & __GFP_FS) != 0;
Looks good to me. But this could be written simpler as:
return ((gfp_mask & (__GFP_WAIT|__GFP_FS)) != 0;
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next prev parent reply other threads:[~2009-05-29 19:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-29 18:10 XFS: prevent deadlock in quota code when recursing into filesystem Felix Blyakher
2009-05-29 18:10 ` [PATCH] xfs: prevent deadlock in xfs_qm_shake() Felix Blyakher
2009-05-29 19:25 ` Christoph Hellwig [this message]
2009-05-29 19:29 ` Felix Blyakher
2009-05-30 10:43 ` Andi Kleen
2009-05-30 14:57 ` Felix Blyakher
2009-05-30 16:14 ` Andi Kleen
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