[PATCH 4.2 116/134] hfs: fix B-tree corruption after insertion at position 0

Greg Kroah-Hartman
2015-09-26T22:01:30Z

From: Hin-Tak Leung <htl10@users.sourceforge.net>

commit b4cc0efea4f0bfa2477c56af406cfcf3d3e58680 upstream.

Fix B-tree corruption when a new record is inserted at position 0 in the
node in hfs_brec_insert().

This is an identical change to the corresponding hfs b-tree code to Sergei
Antonov's "hfsplus: fix B-tree corruption after insertion at position 0",
to keep similar code paths in the hfs and hfsplus drivers in sync, where
appropriate.

Signed-off-by: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Sergei Antonov <saproj@gmail.com>
Cc: Joe Perches <joe@perches.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Anton Altaparmakov <anton@tuxera.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/hfs/brec.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

--- a/fs/hfs/brec.c
+++ b/fs/hfs/brec.c
@@ -131,13 +131,16 @@ skip:
hfs_bnode_write(node, entry, data_off + key_len, entry_len);
hfs_bnode_dump(node);

- if (new_node) {
- /* update parent key if we inserted a key
- * at the start of the first node
- */
- if (!rec && new_node != node)
- hfs_brec_update_parent(fd);
+ /*
+ * update parent key if we inserted a key
+ * at the start of the node and it is not the new node
+ */
+ if (!rec && new_node != node) {
+ hfs_bnode_read_key(node, fd->search_key, data_off + size);
+ hfs_brec_update_parent(fd);
+ }

+ if (new_node) {
hfs_bnode_put(fd->bnode);
if (!new_node->parent) {
hfs_btree_inc_height(tree);
@@ -166,9 +169,6 @@ skip:
goto again;
}

- if (!rec)
- hfs_brec_update_parent(fd);
-
return 0;
}

@@ -366,6 +366,8 @@ again:
if (IS_ERR(parent))
return PTR_ERR(parent);
__hfs_brec_find(parent, fd);
+ if (fd->record < 0)
+ return -ENOENT;
hfs_bnode_dump(parent);
rec = fd->record;