linux-kernel - [PATCH V2] xfs: libxfs: move xfs_perag

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Message-Id: <1543278818-117362-1-git-send-email-bianpan2016@163.com>
Date:   Tue, 27 Nov 2018 08:33:38 +0800
From:   Pan Bian <bianpan2016@....com>
To:     "Darrick J. Wong" <darrick.wong@...cle.com>,
        Brian Foster <bfoster@...hat.com>,
        Dave Chinner <dchinner@...hat.com>,
        Carlos Maiolino <cmaiolino@...hat.com>,
        linux-xfs@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, Pan Bian <bianpan2016@....com>
Subject: [PATCH V2] xfs: libxfs: move xfs_perag_put late

The function xfs_alloc_get_freelist calls xfs_perag_put to drop the
reference. However, pag->pagf_btreeblks is read and write after the 
put operation. This patch moves the put operation late.

Signed-off-by: Pan Bian <bianpan2016@....com>
---
V2: correct the commit log
---
 fs/xfs/libxfs/xfs_alloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_alloc.c b/fs/xfs/libxfs/xfs_alloc.c
index e1c0c0d..4be387d 100644
--- a/fs/xfs/libxfs/xfs_alloc.c
+++ b/fs/xfs/libxfs/xfs_alloc.c
@@ -2435,7 +2435,6 @@ xfs_alloc_get_freelist(
 	be32_add_cpu(&agf->agf_flcount, -1);
 	xfs_trans_agflist_delta(tp, -1);
 	pag->pagf_flcount--;
-	xfs_perag_put(pag);
 
 	logflags = XFS_AGF_FLFIRST | XFS_AGF_FLCOUNT;
 	if (btreeblk) {
@@ -2443,6 +2442,7 @@ xfs_alloc_get_freelist(
 		pag->pagf_btreeblks++;
 		logflags |= XFS_AGF_BTREEBLKS;
 	}
+	xfs_perag_put(pag);
 
 	xfs_alloc_log_agf(tp, agbp, logflags);
 	*bnop = bno;
-- 
2.7.4