Aren/haiku
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

exfat: Add missing locking around SplayTree lookup/insertion.

Browse Source 
A lookup in a splay tree does move the looked up entry to the root of
the tree. This means the tree structure is modified on lookup alone.
Obviously the tree structure is also modified when inserting new nodes.

For both of these reasons access to the f{Node|Ino}Tree needs to be
locked on lookup and insert.

Fixes crashes when the tree is concurrently modified by multiple threads
accessing the same exfat volume.

In addition this protects the fNextId field that hands out new inode
ids.
This commit is contained in:
Michael Lotz 2014-07-26 00:21:20 +02:00
parent 3e2653e609
commit 88b722965a
1 changed files with 3 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
src/add-ons/kernel/file_systems/exfat/Volume.cpp
View File

@ -463,6 +463,8 @@ Volume::GetIno(cluster_t cluster, uint32 offset, ino_t parent)
struct node_key key;
key.cluster = cluster;
key.offset = offset;
MutexLocker locker(fLock);
struct node* node = fNodeTree.Lookup(key);
if (node != NULL) {
TRACE("Volume::GetIno() cached cluster %" B_PRIu32 " offset %" B_PRIu32
@ -484,6 +486,7 @@ Volume::GetIno(cluster_t cluster, uint32 offset, ino_t parent)
struct node_key*
Volume::GetNode(ino_t ino, ino_t &parent)
{
MutexLocker locker(fLock);
struct node* node = fInoTree.Lookup(ino);
if (node != NULL) {
parent = node->parent;