btrfs: fix inode rbtree corruption
Node may not be inserted over existing node. This causes inode tree
corruption and I was seeing crashes in inode_tree_del which I can not
reproduce after this patch.
The other way to fix this would be to tie inode lifetime in the rbtree
with inode while not in freeing state. I had a look at this but it is
not so trivial at this point. At least this patch gets things working again.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Chris Mason <chris.mason@oracle.com>
Acked-by: Yan Zheng <zheng.yan@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 272b9b2..59cba18 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3099,8 +3099,12 @@
{
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_inode *entry;
- struct rb_node **p = &root->inode_tree.rb_node;
- struct rb_node *parent = NULL;
+ struct rb_node **p;
+ struct rb_node *parent;
+
+again:
+ p = &root->inode_tree.rb_node;
+ parent = NULL;
spin_lock(&root->inode_lock);
while (*p) {
@@ -3108,13 +3112,16 @@
entry = rb_entry(parent, struct btrfs_inode, rb_node);
if (inode->i_ino < entry->vfs_inode.i_ino)
- p = &(*p)->rb_left;
+ p = &parent->rb_left;
else if (inode->i_ino > entry->vfs_inode.i_ino)
- p = &(*p)->rb_right;
+ p = &parent->rb_right;
else {
WARN_ON(!(entry->vfs_inode.i_state &
(I_WILL_FREE | I_FREEING | I_CLEAR)));
- break;
+ rb_erase(parent, &root->inode_tree);
+ RB_CLEAR_NODE(parent);
+ spin_unlock(&root->inode_lock);
+ goto again;
}
}
rb_link_node(&BTRFS_I(inode)->rb_node, parent, p);
@@ -3126,12 +3133,12 @@
{
struct btrfs_root *root = BTRFS_I(inode)->root;
+ spin_lock(&root->inode_lock);
if (!RB_EMPTY_NODE(&BTRFS_I(inode)->rb_node)) {
- spin_lock(&root->inode_lock);
rb_erase(&BTRFS_I(inode)->rb_node, &root->inode_tree);
- spin_unlock(&root->inode_lock);
RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
}
+ spin_unlock(&root->inode_lock);
}
static noinline void init_btrfs_i(struct inode *inode)