[PATCH 2.6.32 21/38] [PATCH 21/38] hfs: fix B-tree corruption after insertion at position 0

From: Willy Tarreau
Date: Sun Nov 29 2015 - 17:03:17 EST


2.6.32-longterm review patch. If anyone has any objections, please let me know.

------------------

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@xxxxxxxxxxxxxxxxxxxxx>
Cc: Sergei Antonov <saproj@xxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Reviewed-by: Vyacheslav Dubeyko <slava@xxxxxxxxxxx>
Cc: Anton Altaparmakov <anton@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
(cherry picked from commit d46a34909db526644edf8ae62058d8371dd5f7e9)

Signed-off-by: Willy Tarreau <w@xxxxxx>
---
fs/hfs/brec.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/fs/hfs/brec.c b/fs/hfs/brec.c
index 92fb358..db240c5 100644
--- a/fs/hfs/brec.c
+++ b/fs/hfs/brec.c
@@ -132,13 +132,16 @@ 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);
@@ -167,9 +170,6 @@ 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;

--
1.7.12.2.21.g234cd45.dirty



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