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 <josef@xxxxxxxxxx>
---
fs/btrfs/ioctl.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)
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,
--
1.7.5.2
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