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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Allison Collins <allison.henderson@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH v5 04/14] xfs: Add xfs_has_attr and subroutines
Date: Tue, 21 Jan 2020 14:30:59 -0800	[thread overview]
Message-ID: <20200121223059.GG8247@magnolia> (raw)
In-Reply-To: <2b29c0a0-03bb-8a21-8a8a-fd4754bff3ff@oracle.com>

On Tue, Dec 24, 2019 at 09:21:49PM -0700, Allison Collins wrote:
> On 12/24/19 5:18 AM, Christoph Hellwig wrote:
> > On Wed, Dec 11, 2019 at 09:15:03PM -0700, Allison Collins wrote:
> > > From: Allison Henderson <allison.henderson@oracle.com>
> > > 
> > > This patch adds a new functions to check for the existence of
> > > an attribute.  Subroutines are also added to handle the cases
> > > of leaf blocks, nodes or shortform.  Common code that appears
> > > in existing attr add and remove functions have been factored
> > > out to help reduce the appearance of duplicated code.  We will
> > > need these routines later for delayed attributes since delayed
> > > operations cannot return error codes.
> > 
> > Can you explain why we need the ahead of time check?  The first
> > operation should be able to still return an error, and doing
> > a separate check instead of letting the actual operation fail
> > gracefully is more expensive, and also creates a lot of additional
> > code.  As is I can't say I like the direction at all.
> > 
> 
> This one I can answer quickly: later when we get into delayed attributes,
> this will get called from xfs_defer_finish_noroll as part of a .finish_item
> call back.  If these callbacks return anything other than 0 or -EAGAIN, it
> causes a shutdown.

When does this happen, exactly?  Are you saying that during log
recovery, we can end up replaying a delayed attr log item that hits
ENOATTR/EEXIST somewhere and passes that out, which causes log recovery
to fail?

> Which is not what we would want for example: when the
> user tries to rename a non-existent attribute.  The error code needs to go
> back up.  So we check for things like that before starting a delayed
> operation.  Hope that helps.  Thanks!

...because as far as requests from user programs goes, we should be
doing all these precondition checks after allocating a transaction and
ILOCKing the inode, so that we can send the error code back to userspace
without cancelling a dirty transaction.

(I dunno, am I misunderstanding here?)

> Allison

  reply	other threads:[~2020-01-21 22:31 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-12  4:14 [PATCH v5 00/14] xfs: Delay Ready Attributes Allison Collins
2019-12-12  4:15 ` [PATCH v5 01/14] xfs: Remove all strlen in all xfs_attr_* functions for attr names Allison Collins
2019-12-12  4:15 ` [PATCH v5 02/14] xfs: Replace attribute parameters with struct xfs_name Allison Collins
2019-12-13 13:07   ` Brian Foster
2019-12-14  6:57     ` Allison Collins
2019-12-12  4:15 ` [PATCH v5 03/14] xfs: Embed struct xfs_name in xfs_da_args Allison Collins
2019-12-12  4:15 ` [PATCH v5 04/14] xfs: Add xfs_has_attr and subroutines Allison Collins
2019-12-13 13:08   ` Brian Foster
2019-12-14  6:58     ` Allison Collins
2019-12-24 12:18   ` Christoph Hellwig
2019-12-25  4:21     ` Allison Collins
2020-01-21 22:30       ` Darrick J. Wong [this message]
2020-01-22  0:25         ` Allison Collins
2020-01-25 16:27           ` Allison Collins
2020-01-25 23:08             ` Christoph Hellwig
2020-01-26  4:03               ` Allison Collins
2019-12-12  4:15 ` [PATCH v5 05/14] xfs: Factor out new helper functions xfs_attr_rmtval_set Allison Collins
2019-12-24 12:14   ` Christoph Hellwig
2019-12-25 17:43     ` Allison Collins
2020-01-06 14:46       ` Brian Foster
2020-01-06 18:29         ` Allison Collins
2020-01-06 21:45           ` Darrick J. Wong
2020-01-06 23:33             ` Dave Chinner
2019-12-12  4:15 ` [PATCH v5 06/14] xfs: Factor up trans handling in xfs_attr3_leaf_flipflags Allison Collins
2019-12-24 12:16   ` Christoph Hellwig
2019-12-25 20:49     ` Allison Collins
2019-12-12  4:15 ` [PATCH v5 07/14] xfs: Factor out xfs_attr_leaf_addname helper Allison Collins
2019-12-13 14:15   ` Brian Foster
2019-12-14  6:58     ` Allison Collins
2019-12-24 12:22   ` Christoph Hellwig
2019-12-26 17:04     ` Allison Collins
2019-12-12  4:15 ` [PATCH v5 08/14] xfs: Factor up xfs_attr_try_sf_addname Allison Collins
2019-12-13 14:15   ` Brian Foster
2019-12-14  6:58     ` Allison Collins
2019-12-24 12:25   ` Christoph Hellwig
2019-12-27  3:23     ` Allison Collins
2019-12-12  4:15 ` [PATCH v5 09/14] xfs: Factor up trans roll from xfs_attr3_leaf_setflag Allison Collins
2019-12-24 12:26   ` Christoph Hellwig
2019-12-12  4:15 ` [PATCH v5 10/14] xfs: Factor out xfs_attr_rmtval_invalidate Allison Collins
2019-12-12  4:15 ` [PATCH v5 11/14] xfs: Factor up trans roll in xfs_attr3_leaf_clearflag Allison Collins
2019-12-24 12:28   ` Christoph Hellwig
2019-12-12  4:15 ` [PATCH v5 12/14] xfs: Check for -ENOATTR or -EEXIST Allison Collins
2019-12-13 14:16   ` Brian Foster
2019-12-14  7:56     ` Allison Collins
2019-12-12  4:15 ` [PATCH v5 13/14] xfs: Add delay ready attr remove routines Allison Collins
2019-12-13 17:30   ` Brian Foster
2019-12-14 19:21     ` Allison Collins
2019-12-24 12:30   ` Christoph Hellwig
2019-12-24 23:18     ` Allison Collins
2019-12-12  4:15 ` [PATCH v5 14/14] xfs: Add delay ready attr set routines Allison Collins
2019-12-24 12:02 ` [PATCH v5 00/14] xfs: Delay Ready Attributes Christoph Hellwig

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