From: tytso@mit.edu
To: Dmitry Monakhov <dmonakhov@openvz.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
linux-ext4@vger.kernel.org
Subject: Re: [PATCH 2/4] ext4: fix reserved space transferring on chown() [V2]
Date: Tue, 8 Dec 2009 20:42:59 -0500 [thread overview]
Message-ID: <20091209014259.GV27692@thunk.org> (raw)
In-Reply-To: <87ocmalgh0.fsf@openvz.org>
On Mon, Dec 07, 2009 at 10:41:15PM +0300, Dmitry Monakhov wrote:
> Absolutely right. I've fixed an issue, but overlooked the BIGGEST one.
> So off course my patch is wrong, even if we will acquire lock in
> different order " dqptr_sem > i_block_reservation_lock"
> we sill getting in to sleeping spin lock problems by following scenario:
> ext4_da_update_reserve_space()
> ->dquot_claim_space()
> ASSUMES that we hold i_block_reservation_lock here.
> -->mark_dquot_dirty()
> --->ext4_write_dquot()
> if (journalled quota) ext4_write_dquot();
> ---->dquot_commit()
> ----->mutex_lock(&dqopt->dqio_mutt's); <<< sleep here.
>
> This means that we have fully redesign quota reservation locking.
> As i already suggested previously here:
> http://thread.gmane.org/gmane.comp.file-systems.ext4/16576/focus=16587
Given this, should I include this patch for now, given that it does
fix _one_ race, or should I hold off until you redo the locking? How
long do you think to send a revised/new patch?
- Ted
next prev parent reply other threads:[~2009-12-09 1:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-25 6:57 [PATCH 1/4] ext4: ext4_get_reserved_space() must return bytes instead of blocks Dmitry Monakhov
2009-11-25 6:57 ` [PATCH 2/4] ext4: fix reserved space transferring on chown() [V2] Dmitry Monakhov
2009-11-25 6:57 ` [PATCH 3/4] ext4: quota macros cleanup Dmitry Monakhov
2009-11-25 6:57 ` [PATCH 4/4] ext4: fix incorrect block reservation on quota transfer Dmitry Monakhov
2009-12-08 1:02 ` Mingming
2009-12-08 6:48 ` Dmitry Monakhov
2009-12-08 0:59 ` [PATCH 3/4] ext4: quota macros cleanup Mingming
2009-12-07 17:18 ` [PATCH 2/4] ext4: fix reserved space transferring on chown() [V2] Aneesh Kumar K.V
2009-12-07 19:41 ` Dmitry Monakhov
2009-12-09 1:42 ` tytso [this message]
2009-12-09 2:03 ` Dmitry Monakhov
2009-12-08 23:06 ` Mingming
2009-11-25 16:32 ` [PATCH 1/4] ext4: ext4_get_reserved_space() must return bytes instead of blocks Eric Sandeen
2009-12-08 1:04 ` Mingming
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