From 0a3021d4f5295aa073c7bf5c5e4de60a2e292578 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ernesto=20A=2E=20Fern=C3=A1ndez?= <ernesto.mnd.fernandez@gmail.com>
Date: Tue, 30 Oct 2018 15:06:00 -0700
Subject: [PATCH] hfsplus: prevent btree data loss on root split
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Git-commit: 0a3021d4f5295aa073c7bf5c5e4de60a2e292578
Patch-mainline: v4.20-rc1
References: bsc#1051510
Creating, renaming or deleting a file may cause catalog corruption and
data loss. This bug is randomly triggered by xfstests generic/027, but
here is a faster reproducer:
truncate -s 50M fs.iso
mkfs.hfsplus fs.iso
mount fs.iso /mnt
i=100
while [ $i -le 150 ]; do
touch /mnt/$i &>/dev/null
((++i))
done
i=100
while [ $i -le 150 ]; do
mv /mnt/$i /mnt/$(perl -e "print $i x82") &>/dev/null
((++i))
done
umount /mnt
fsck.hfsplus -n fs.iso
The bug is triggered whenever hfs_brec_update_parent() needs to split the
root node. The height of the btree is not increased, which leaves the new
node orphaned and its records lost.
Link: http://lkml.kernel.org/r/26d882184fc43043a810114258f45277752186c7.1535682461.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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
fs/hfsplus/brec.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/hfsplus/brec.c b/fs/hfsplus/brec.c
index ed8eacb34452..aa17a392b414 100644
--- a/fs/hfsplus/brec.c
+++ b/fs/hfsplus/brec.c
@@ -429,6 +429,10 @@ static int hfs_brec_update_parent(struct hfs_find_data *fd)
if (new_node) {
__be32 cnid;
+ if (!new_node->parent) {
+ hfs_btree_inc_height(tree);
+ new_node->parent = tree->root;
+ }
fd->bnode = hfs_bnode_find(tree, new_node->parent);
/* create index key and entry */
hfs_bnode_read_key(new_node, fd->search_key, 14);
--
2.16.4