From 17de39ac17bf99b8bf0d819d13668d5048836efc Mon Sep 17 00:00:00 2001
From: Josef Bacik <josef@redhat.com>
Date: Fri, 4 May 2012 15:16:06 -0400
Subject: [PATCH] Btrfs: fix page leak when allocing extent buffers

If we happen to alloc a extent buffer and then alloc a page and notice that
page is already attached to an extent buffer, we will only unlock it and
free our existing eb.  Any pages currently attached to that eb will be
properly freed, but we don't do the page_cache_release() on the page where
we noticed the other extent buffer which can cause us to leak pages and I
hope cause the weird issues we've been seeing in this area.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---
 fs/btrfs/extent_io.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 0c23e57077c6f7..2fb52c26c677d2 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4120,6 +4120,7 @@ struct extent_buffer *alloc_extent_buffer(struct extent_io_tree *tree,
 			if (atomic_inc_not_zero(&exists->refs)) {
 				spin_unlock(&mapping->private_lock);
 				unlock_page(p);
+				page_cache_release(p);
 				mark_extent_buffer_accessed(exists);
 				goto free_eb;
 			}
@@ -4199,8 +4200,7 @@ free_eb:
 			unlock_page(eb->pages[i]);
 	}
 
-	if (!atomic_dec_and_test(&eb->refs))
-		return exists;
+	WARN_ON(!atomic_dec_and_test(&eb->refs));
 	btrfs_release_extent_buffer(eb);
 	return exists;
 }
-- 
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