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From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-xfs@vger.kernel.org, hch@infradead.org
Subject: Re: [PATCH 10/12] xfs: make xfs_*read_agf return EAGAIN to ALLOC_FLAG_TRYLOCK callers
Date: Thu, 23 Jan 2020 20:47:28 -0800	[thread overview]
Message-ID: <20200124044728.GD8247@magnolia> (raw)
In-Reply-To: <20200124020054.GK7090@dread.disaster.area>

On Fri, Jan 24, 2020 at 01:00:54PM +1100, Dave Chinner wrote:
> On Wed, Jan 22, 2020 at 11:42:54PM -0800, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> > 
> > Refactor xfs_read_agf and xfs_alloc_read_agf to return EAGAIN if the
> > caller passed TRYLOCK and we weren't able to get the lock; and change
> > the callers to recognize this.
> > 
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> > ---
> >  fs/xfs/libxfs/xfs_alloc.c |   34 +++++++++++++++-------------------
> >  fs/xfs/libxfs/xfs_bmap.c  |   11 ++++++-----
> >  fs/xfs/xfs_filestream.c   |   11 ++++++-----
> >  3 files changed, 27 insertions(+), 29 deletions(-)
> .....
> > @@ -2992,10 +2987,11 @@ xfs_alloc_read_agf(
> >  	error = xfs_read_agf(mp, tp, agno,
> >  			(flags & XFS_ALLOC_FLAG_TRYLOCK) ? XBF_TRYLOCK : 0,
> >  			bpp);
> > -	if (error)
> > +	if (error) {
> > +		/* We don't support trylock when freeing. */
> > +		ASSERT(error != -EAGAIN || !(flags & XFS_ALLOC_FLAG_FREEING));
> >  		return error;
> 
> Shouldn't we check this with asserts before we call xfs_read_agf()?
> i.e.
> 
> 	/* We don't support trylock when freeing. */
> 	ASSERT((flags & (XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK)) !=
> 			(XFS_ALLOC_FLAG_FREEING | XFS_ALLOC_FLAG_TRYLOCK));
> 	....

Yeah.

> > -	if (!*bpp)
> > -		return 0;
> > +	}
> >  	ASSERT(!(*bpp)->b_error);
> >  
> >  	agf = XFS_BUF_TO_AGF(*bpp);
> > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
> > index cfcef076c72f..9a6d7a84689a 100644
> > --- a/fs/xfs/libxfs/xfs_bmap.c
> > +++ b/fs/xfs/libxfs/xfs_bmap.c
> > @@ -3311,11 +3311,12 @@ xfs_bmap_longest_free_extent(
> >  	pag = xfs_perag_get(mp, ag);
> >  	if (!pag->pagf_init) {
> >  		error = xfs_alloc_pagf_init(mp, tp, ag, XFS_ALLOC_FLAG_TRYLOCK);
> > -		if (error)
> > -			goto out;
> > -
> > -		if (!pag->pagf_init) {
> > -			*notinit = 1;
> > +		if (error) {
> > +			/* Couldn't lock the AGF, so skip this AG. */
> > +			if (error == -EAGAIN) {
> > +				*notinit = 1;
> > +				error = 0;
> > +			}
> >  			goto out;
> >  		}
> >  	}
> > diff --git a/fs/xfs/xfs_filestream.c b/fs/xfs/xfs_filestream.c
> > index 5f12b5d8527a..3ccdab463359 100644
> > --- a/fs/xfs/xfs_filestream.c
> > +++ b/fs/xfs/xfs_filestream.c
> > @@ -159,16 +159,17 @@ xfs_filestream_pick_ag(
> >  
> >  		if (!pag->pagf_init) {
> >  			err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
> > -			if (err && !trylock) {
> > +			if (err == -EAGAIN) {
> > +				/* Couldn't lock the AGF, skip this AG. */
> > +				xfs_perag_put(pag);
> > +				continue;
> > +			}
> > +			if (err) {
> >  				xfs_perag_put(pag);
> >  				return err;
> >  			}
> 
> Might neater to do:
> 
> 		if (!pag->pagf_init) {
> 			err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
> 			if (err) {
> 				xfs_perag_put(pag);
> 				if (err != -EAGAIN)
> 					return err;
> 				/* Couldn't lock the AGF, skip this AG. */
> 				continue;
> 			}
> 		}
> 
> Otherwise it all looks ok.

Cool.  Will fix.

--D

> 
> -Dave
> -- 
> Dave Chinner
> david@fromorbit.com

  reply	other threads:[~2020-01-24  4:47 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-23  7:41 [PATCH v4 00/12] xfs: make buffer functions return error codes Darrick J. Wong
2020-01-23  7:41 ` [PATCH 01/12] xfs: make xfs_buf_alloc return an error code Darrick J. Wong
2020-01-24  0:47   ` Dave Chinner
2020-01-23  7:42 ` [PATCH 02/12] xfs: make xfs_buf_read " Darrick J. Wong
2020-01-23 22:20   ` Christoph Hellwig
2020-01-24  0:16     ` Darrick J. Wong
2020-01-24  1:08       ` Darrick J. Wong
2020-01-24  0:49   ` Dave Chinner
2020-01-23  7:42 ` [PATCH 03/12] xfs: make xfs_buf_get " Darrick J. Wong
2020-01-24  0:50   ` Dave Chinner
2020-01-23  7:42 ` [PATCH 04/12] xfs: make xfs_buf_get_uncached " Darrick J. Wong
2020-01-24  0:53   ` Dave Chinner
2020-01-23  7:42 ` [PATCH 05/12] xfs: make xfs_buf_read_map " Darrick J. Wong
2020-01-23 22:24   ` Christoph Hellwig
2020-01-24  0:23     ` Darrick J. Wong
2020-01-24  4:59       ` Darrick J. Wong
2020-01-24  1:31   ` Dave Chinner
2020-01-24  4:34     ` Darrick J. Wong
2020-01-23  7:42 ` [PATCH 06/12] xfs: make xfs_buf_get_map " Darrick J. Wong
2020-01-24  1:41   ` Dave Chinner
2020-01-23  7:42 ` [PATCH 07/12] xfs: make xfs_trans_get_buf_map " Darrick J. Wong
2020-01-24  1:44   ` Dave Chinner
2020-01-23  7:42 ` [PATCH 08/12] xfs: make xfs_trans_get_buf " Darrick J. Wong
2020-01-24  1:48   ` Dave Chinner
2020-01-23  7:42 ` [PATCH 09/12] xfs: remove the xfs_btree_get_buf[ls] functions Darrick J. Wong
2020-01-24  1:50   ` Dave Chinner
2020-01-23  7:42 ` [PATCH 10/12] xfs: make xfs_*read_agf return EAGAIN to ALLOC_FLAG_TRYLOCK callers Darrick J. Wong
2020-01-24  2:00   ` Dave Chinner
2020-01-24  4:47     ` Darrick J. Wong [this message]
2020-01-23  7:43 ` [PATCH 11/12] xfs: remove unnecessary null pointer checks from _read_agf callers Darrick J. Wong
2020-01-24  2:01   ` Dave Chinner
2020-01-23  7:43 ` [PATCH 12/12] xfs: fix xfs_buf_ioerror_alert location reporting Darrick J. Wong
2020-01-24  2:07   ` Dave Chinner
2020-01-24  4:21     ` Darrick J. Wong
2020-01-24  5:18 [PATCH v5 00/12] xfs: make buffer functions return error codes Darrick J. Wong
2020-01-24  5:20 ` [PATCH 10/12] xfs: make xfs_*read_agf return EAGAIN to ALLOC_FLAG_TRYLOCK callers Darrick J. Wong
2020-01-24 22:07   ` Dave Chinner
2020-01-24 23:12   ` Christoph Hellwig
2020-01-26  2:43     ` Christoph Hellwig

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