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From: Christoph Hellwig <hch@lst.de>
To: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: Christoph Hellwig <hch@lst.de>,
	clm@fb.com, josef@toxicpanda.com, dsterba@suse.com,
	linux-btrfs@vger.kernel.org
Subject: Re: [PATCH] btrfs: the raid56 code does not need irqsafe locking
Date: Fri, 20 Jan 2023 09:15:09 +0100	[thread overview]
Message-ID: <20230120081509.GA27910@lst.de> (raw)
In-Reply-To: <20230120081342.GA27851@lst.de>

On Fri, Jan 20, 2023 at 09:13:42AM +0100, Christoph Hellwig wrote:
> On Fri, Jan 20, 2023 at 04:05:07PM +0800, Qu Wenruo wrote:
> > And thanks to the patch, I exposed that for read/write endio, we lacks 
> > spinlocks for bitmap operations.
> >
> > As we still have chances to have multiple bios for the same stripe, and 
> > bitmap operations themselves are not atomic.
> 
> So, bitmap_set is indeed not atomic.  But if you switch to the
> set_bit that should be enough here.

... but might actually be less efficient than the bitmap.

  reply	other threads:[~2023-01-20  8:15 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-20  7:46 [PATCH] btrfs: the raid56 code does not need irqsafe locking Christoph Hellwig
2023-01-20  8:05 ` Qu Wenruo
2023-01-20  8:13   ` Christoph Hellwig
2023-01-20  8:15     ` Christoph Hellwig [this message]
2023-01-20  8:36       ` Qu Wenruo
2023-02-15 20:13 ` David Sterba
2023-02-20 20:06   ` David Sterba

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