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From: Liu Bo <bo.li.liu@oracle.com>
To: linux-btrfs@vger.kernel.org
Subject: [PATCH 6/8] Btrfs: save us a read_lock
Date: Thu, 27 Dec 2012 17:01:22 +0800	[thread overview]
Message-ID: <1356598884-22952-6-git-send-email-bo.li.liu@oracle.com> (raw)
In-Reply-To: <1356598884-22952-1-git-send-email-bo.li.liu@oracle.com>

This does not change the logic of code, but can save us a read_lock.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
---
 fs/btrfs/locking.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/btrfs/locking.c b/fs/btrfs/locking.c
index 2a1762c..e95df43 100644
--- a/fs/btrfs/locking.c
+++ b/fs/btrfs/locking.c
@@ -113,11 +113,10 @@ again:
 		read_unlock(&eb->lock);
 		return;
 	}
-	read_unlock(&eb->lock);
-	wait_event(eb->write_lock_wq, atomic_read(&eb->blocking_writers) == 0);
-	read_lock(&eb->lock);
 	if (atomic_read(&eb->blocking_writers)) {
 		read_unlock(&eb->lock);
+		wait_event(eb->write_lock_wq,
+			   atomic_read(&eb->blocking_writers) == 0);
 		goto again;
 	}
 	atomic_inc(&eb->read_locks);
-- 
1.7.7.6


  parent reply	other threads:[~2012-12-27  9:03 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-12-27  9:01 [PATCH 1/8] Btrfs: remove deprecated comments Liu Bo
2012-12-27  9:01 ` [PATCH 2/8] Btrfs: kill unused arguments of cache_block_group Liu Bo
2012-12-27  9:01 ` [PATCH 3/8] Btrfs: kill unused argument of update_block_group Liu Bo
2012-12-27  9:01 ` [PATCH 4/8] Btrfs: kill unused argument of btrfs_pin_extent_for_log_replay Liu Bo
2012-12-27  9:01 ` [PATCH 5/8] Btrfs: use token to avoid times mapping extent buffer Liu Bo
2012-12-27  9:01 ` Liu Bo [this message]
2012-12-27  9:01 ` [PATCH 7/8] Btrfs: record first logical byte in memory Liu Bo
2012-12-27  9:01 ` [PATCH 8/8] Btrfs: let allocation start from the right raid type Liu Bo
2013-01-03 16:37 ` [PATCH 1/8] Btrfs: remove deprecated comments David Sterba

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