[PATCH AUTOSEL 4.14 095/150] hfsplus: fix BUG on bnode parent update

Sasha Levin
2019-11-16T15:49:47Z

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 d3f36982f6858..0f53a486d2c18 100644
--- a/fs/hfsplus/brec.c
+++ b/fs/hfsplus/brec.c
@@ -448,6 +448,7 @@ 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