From 8351583e3f6e430ce8f71913909a96ad5cc6a2f6 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Tue, 14 Jun 2011 15:16:14 -0400 Subject: [PATCH] Btrfs: protect the pending_snapshots list with trans_lock Currently there is nothing protecting the pending_snapshots list on the transaction. We only hold the directory mutex that we are snapshotting and a read lock on the subvol_sem, so we could race with somebody else creating a snapshot in a different directory and end up with list corruption. So protect this list with the trans_lock. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/ioctl.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index b793d11..a3c4751 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -482,8 +482,10 @@ static int create_snapshot(struct btrfs_root *root, struct dentry *dentry, ret = btrfs_snap_reserve_metadata(trans, pending_snapshot); BUG_ON(ret); + spin_lock(&root->fs_info->trans_lock); list_add(&pending_snapshot->list, &trans->transaction->pending_snapshots); + spin_unlock(&root->fs_info->trans_lock); if (async_transid) { *async_transid = trans->transid; ret = btrfs_commit_transaction_async(trans, -- 2.7.4