diff options
| -rw-r--r-- | fs/btrfs/ctree.c | 4 | ||||
| -rw-r--r-- | fs/btrfs/ctree.h | 1 | ||||
| -rw-r--r-- | fs/btrfs/extent-tree.c | 9 |
3 files changed, 14 insertions, 0 deletions
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 5912a97b07a6..72745235896f 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -1440,6 +1440,10 @@ noinline int btrfs_cow_block(struct btrfs_trans_handle *trans, u64 search_start; int ret; + if (test_bit(BTRFS_ROOT_DELETING, &root->state)) + btrfs_err(fs_info, + "COW'ing blocks on a fs root that's being dropped"); + if (trans->transaction != fs_info->running_transaction) WARN(1, KERN_CRIT "trans %llu running %llu\n", trans->transid, diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 6520e8e70b09..f031a447a047 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1197,6 +1197,7 @@ enum { BTRFS_ROOT_FORCE_COW, BTRFS_ROOT_MULTI_LOG_TASKS, BTRFS_ROOT_DIRTY, + BTRFS_ROOT_DELETING, }; /* diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 306e33d49602..de21e0c93eb6 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -9275,6 +9275,15 @@ int btrfs_drop_snapshot(struct btrfs_root *root, if (block_rsv) trans->block_rsv = block_rsv; + /* + * This will help us catch people modifying the fs tree while we're + * dropping it. It is unsafe to mess with the fs tree while it's being + * dropped as we unlock the root node and parent nodes as we walk down + * the tree, assuming nothing will change. If something does change + * then we'll have stale information and drop references to blocks we've + * already dropped. + */ + set_bit(BTRFS_ROOT_DELETING, &root->state); if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) { level = btrfs_header_level(root->node); path->nodes[level] = btrfs_lock_root_node(root); |