From 6de5f18e7b0da0cdd265eda047a0bc4f48260bcb Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 3 Mar 2017 10:55:16 +0200 Subject: [PATCH] btrfs: convert btrfs_delayed_node.refs from atomic_t to refcount_t refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor Signed-off-by: David Sterba --- fs/btrfs/delayed-inode.c | 28 ++++++++++++++-------------- fs/btrfs/delayed-inode.h | 4 ++-- 2 files changed, 16 insertions(+), 16 deletions(-) diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c index 1aff676f0e5b..7396c36e0adb 100644 --- a/fs/btrfs/delayed-inode.c +++ b/fs/btrfs/delayed-inode.c @@ -52,7 +52,7 @@ static inline void btrfs_init_delayed_node( { delayed_node->root = root; delayed_node->inode_id = inode_id; - atomic_set(&delayed_node->refs, 0); + refcount_set(&delayed_node->refs, 0); delayed_node->ins_root = RB_ROOT; delayed_node->del_root = RB_ROOT; mutex_init(&delayed_node->mutex); @@ -81,7 +81,7 @@ static struct btrfs_delayed_node *btrfs_get_delayed_node( node = READ_ONCE(btrfs_inode->delayed_node); if (node) { - atomic_inc(&node->refs); + refcount_inc(&node->refs); return node; } @@ -89,14 +89,14 @@ static struct btrfs_delayed_node *btrfs_get_delayed_node( node = radix_tree_lookup(&root->delayed_nodes_tree, ino); if (node) { if (btrfs_inode->delayed_node) { - atomic_inc(&node->refs); /* can be accessed */ + refcount_inc(&node->refs); /* can be accessed */ BUG_ON(btrfs_inode->delayed_node != node); spin_unlock(&root->inode_lock); return node; } btrfs_inode->delayed_node = node; /* can be accessed and cached in the inode */ - atomic_add(2, &node->refs); + refcount_add(2, &node->refs); spin_unlock(&root->inode_lock); return node; } @@ -125,7 +125,7 @@ again: btrfs_init_delayed_node(node, root, ino); /* cached in the btrfs inode and can be accessed */ - atomic_add(2, &node->refs); + refcount_set(&node->refs, 2); ret = radix_tree_preload(GFP_NOFS); if (ret) { @@ -166,7 +166,7 @@ static void btrfs_queue_delayed_node(struct btrfs_delayed_root *root, } else { list_add_tail(&node->n_list, &root->node_list); list_add_tail(&node->p_list, &root->prepare_list); - atomic_inc(&node->refs); /* inserted into list */ + refcount_inc(&node->refs); /* inserted into list */ root->nodes++; set_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags); } @@ -180,7 +180,7 @@ static void btrfs_dequeue_delayed_node(struct btrfs_delayed_root *root, spin_lock(&root->lock); if (test_bit(BTRFS_DELAYED_NODE_IN_LIST, &node->flags)) { root->nodes--; - atomic_dec(&node->refs); /* not in the list */ + refcount_dec(&node->refs); /* not in the list */ list_del_init(&node->n_list); if (!list_empty(&node->p_list)) list_del_init(&node->p_list); @@ -201,7 +201,7 @@ static struct btrfs_delayed_node *btrfs_first_delayed_node( p = delayed_root->node_list.next; node = list_entry(p, struct btrfs_delayed_node, n_list); - atomic_inc(&node->refs); + refcount_inc(&node->refs); out: spin_unlock(&delayed_root->lock); @@ -228,7 +228,7 @@ static struct btrfs_delayed_node *btrfs_next_delayed_node( p = node->n_list.next; next = list_entry(p, struct btrfs_delayed_node, n_list); - atomic_inc(&next->refs); + refcount_inc(&next->refs); out: spin_unlock(&delayed_root->lock); @@ -253,11 +253,11 @@ static void __btrfs_release_delayed_node( btrfs_dequeue_delayed_node(delayed_root, delayed_node); mutex_unlock(&delayed_node->mutex); - if (atomic_dec_and_test(&delayed_node->refs)) { + if (refcount_dec_and_test(&delayed_node->refs)) { bool free = false; struct btrfs_root *root = delayed_node->root; spin_lock(&root->inode_lock); - if (atomic_read(&delayed_node->refs) == 0) { + if (refcount_read(&delayed_node->refs) == 0) { radix_tree_delete(&root->delayed_nodes_tree, delayed_node->inode_id); free = true; @@ -286,7 +286,7 @@ static struct btrfs_delayed_node *btrfs_first_prepared_delayed_node( p = delayed_root->prepare_list.next; list_del_init(p); node = list_entry(p, struct btrfs_delayed_node, p_list); - atomic_inc(&node->refs); + refcount_inc(&node->refs); out: spin_unlock(&delayed_root->lock); @@ -1621,7 +1621,7 @@ bool btrfs_readdir_get_delayed_items(struct inode *inode, * insert/delete delayed items in this period. So we also needn't * requeue or dequeue this delayed node. */ - atomic_dec(&delayed_node->refs); + refcount_dec(&delayed_node->refs); return true; } @@ -1963,7 +1963,7 @@ void btrfs_kill_all_delayed_nodes(struct btrfs_root *root) inode_id = delayed_nodes[n - 1]->inode_id + 1; for (i = 0; i < n; i++) - atomic_inc(&delayed_nodes[i]->refs); + refcount_inc(&delayed_nodes[i]->refs); spin_unlock(&root->inode_lock); for (i = 0; i < n; i++) { diff --git a/fs/btrfs/delayed-inode.h b/fs/btrfs/delayed-inode.h index 40327cc3b99a..2f494fdde0ac 100644 --- a/fs/btrfs/delayed-inode.h +++ b/fs/btrfs/delayed-inode.h @@ -26,7 +26,7 @@ #include #include #include - +#include #include "ctree.h" /* types of the delayed item */ @@ -67,7 +67,7 @@ struct btrfs_delayed_node { struct rb_root del_root; struct mutex mutex; struct btrfs_inode_item inode_item; - atomic_t refs; + refcount_t refs; u64 index_cnt; unsigned long flags; int count; -- 2.20.1