releases/4.19.87/hfsplus-fix-bug-on-bnode-parent-update.patch

From d1ce1b8b0edf4f3a620bd522fd1337e674b407b1 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Tue, 30 Oct 2018 15:06:04 -0700
Subject: hfsplus: fix BUG on bnode parent update
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From: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>

[ Upstream commit 19a9d0f1acf75e8be8cfba19c1a34e941846fa2b ]

Creating, renaming or deleting a file may hit BUG_ON() if the first
record of both a leaf node and its parent are changed, and if this
forces the parent to be split.  This bug is triggered by xfstests
generic/027, somewhat rarely; here is a more reliable reproducer:

  truncate -s 50M fs.iso
  mkfs.hfsplus fs.iso
  mount fs.iso /mnt
  i=1000
  while [ $i -le 2400 ]; do
    touch /mnt/$i &>/dev/null
    ((++i))
  done
  i=2400
  while [ $i -ge 1000 ]; do
    mv /mnt/$i /mnt/$(perl -e "print $i x61") &>/dev/null
    ((--i))
  done

The issue is that a newly created bnode is being put twice.  Reset
new_node to NULL in hfs_brec_update_parent() before reaching goto again.

Link: http://lkml.kernel.org/r/5ee1db09b60373a15890f6a7c835d00e76bf601d.1535682461.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfsplus/brec.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/hfsplus/brec.c b/fs/hfsplus/brec.c
index aa17a392b4140..1918544a78716 100644
--- a/fs/hfsplus/brec.c
+++ b/fs/hfsplus/brec.c
@@ -449,6 +449,7 @@ static int hfs_brec_update_parent(struct hfs_find_data *fd)
 			/* restore search_key */
 			hfs_bnode_read_key(node, fd->search_key, 14);
 		}
+		new_node = NULL;
 	}
 
 	if (!rec && node->parent)
-- 
2.20.1