Btrfs: fix use-after-free in __btrfs_end_transaction
49b25e0540904be0bf558b84475c69d72e4de66e introduced a use-after-free bug
that caused spurious -EIO's to be returned.
Do the check before we free the transaction.
Cc: David Sterba <dsterba@suse.cz>
Cc: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 8da29e8..11b77a5 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -480,6 +480,7 @@
struct btrfs_transaction *cur_trans = trans->transaction;
struct btrfs_fs_info *info = root->fs_info;
int count = 0;
+ int err = 0;
if (--trans->use_count) {
trans->block_rsv = trans->orig_rsv;
@@ -532,18 +533,18 @@
if (current->journal_info == trans)
current->journal_info = NULL;
- memset(trans, 0, sizeof(*trans));
- kmem_cache_free(btrfs_trans_handle_cachep, trans);
if (throttle)
btrfs_run_delayed_iputs(root);
if (trans->aborted ||
root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
- return -EIO;
+ err = -EIO;
}
- return 0;
+ memset(trans, 0, sizeof(*trans));
+ kmem_cache_free(btrfs_trans_handle_cachep, trans);
+ return err;
}
int btrfs_end_transaction(struct btrfs_trans_handle *trans,