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authorJosef Bacik <josef@redhat.com>2011-06-14 15:16:14 -0400
committerJosef Bacik <josef@redhat.com>2011-06-15 13:24:46 -0400
commit8351583e3f6e430ce8f71913909a96ad5cc6a2f6 (patch)
treef345f40f94d12ffe090735f19aebc96c72be44bd /fs
parent71d7aed014457147e8f71a843d5fbf03235e4a85 (diff)
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 <josef@redhat.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/ioctl.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index b793d112d1f6..a3c4751e07db 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,