[PATCH] xfs: unlock the AGI buffer when looping in xfs_dialloc

[PATCH] xfs: unlock the AGI buffer when looping in xfs_dialloc

[Christoph Hellwig]

Also update some commens in the area to make the code easier to read.

Signed-off-by: Christoph Hellwig <hch@lst.de>

---
 fs/xfs/xfs_ialloc.c |   17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

Index: xfs/fs/xfs/xfs_ialloc.c
===================================================================
--- xfs.orig/fs/xfs/xfs_ialloc.c	2012-08-07 07:33:49.750001911 +0200
+++ xfs/fs/xfs/xfs_ialloc.c	2012-08-07 07:34:14.393335258 +0200
@@ -962,23 +962,22 @@ xfs_dialloc(
 		if (!pag->pagi_freecount && !okalloc)
 			goto nextag;
 
+		/*
+		 * Then read in the AGI buffer and recheck with the AGI buffer
+		 * lock held.
+		 */
 		error = xfs_ialloc_read_agi(mp, tp, agno, &agbp);
 		if (error)
 			goto out_error;
 
-		/*
-		 * Once the AGI has been read in we have to recheck
-		 * pagi_freecount with the AGI buffer lock held.
-		 */
 		if (pag->pagi_freecount) {
 			xfs_perag_put(pag);
 			goto out_alloc;
 		}
 
-		if (!okalloc) {
-			xfs_trans_brelse(tp, agbp);
-			goto nextag;
-		}
+		if (!okalloc)
+			goto nextag_relse_buffer;
+
 
 		error = xfs_ialloc_ag_alloc(tp, agbp, &ialloced);
 		if (error) {
@@ -1007,6 +1006,8 @@ xfs_dialloc(
 			return 0;
 		}
 
+nextag_relse_buffer:
+		xfs_trans_brelse(tp, agbp);
 nextag:
 		xfs_perag_put(pag);
 		if (++agno == mp->m_sb.sb_agcount)

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Re: [PATCH] xfs: unlock the AGI buffer when looping in xfs_dialloc

[Mark Tinguely]

On 08/07/12 01:02, Christoph Hellwig wrote:
> Also update some commens in the area to make the code easier to read.
>
> Signed-off-by: Christoph Hellwig<hch@lst.de>
>

Looks great. Just last weekend, I noticed that the unlock is also
missing in the current version of xfs_dialloc() and not just patch #7.

Reviewed-by: Mark Tinguely <tinguely@sgi.com>

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Re: [PATCH] xfs: unlock the AGI buffer when looping in xfs_dialloc

[Dave Chinner]

On Tue, Aug 07, 2012 at 02:02:02AM -0400, Christoph Hellwig wrote:
> Also update some commens in the area to make the code easier to read.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

Looks good.

Reviewed-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com

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Re: [PATCH] xfs: unlock the AGI buffer when looping in xfs_dialloc

[Ben Myers]

Hey Christoph,

On Tue, Aug 07, 2012 at 02:02:02AM -0400, Christoph Hellwig wrote:
> Also update some commens in the area to make the code easier to read.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>

This seems to fix a regression that was introduced in

commit 55d6af64, 'xfs: refactor xfs_ialloc_ag_select'

Christoph, could you comment on why this has not caused problems in testing?  I
am sort of suprised we haven't had any ill effects.

I'll add this patch into our next pull request.

Thanks,
	Ben

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