On Thu, Jul 27, 2023 at 01:28:39PM -0400, Gabriel Krisman Bertazi wrote: > - In __lookup_slow, either the parent inode is read locked by the > caller (lookup_slow), or it is called with no flags (lookup_one*). > The read lock suffices to prevent ->d_name modifications, with the > exception of one case: __d_unalias, will call __d_move to fix a > directory accessible from multiple dentries, which effectively swaps > ->d_name while holding only the shared read lock. This happens > through this flow: > > lookup_slow() //LOOKUP_CREATE > d_lookup() > ->d_lookup() > d_splice_alias() > __d_unalias() > __d_move() > > Nevertheless, this case is not a problem because negative dentries > are not allowed to be moved with __d_move. Isn't it possible for a negative dentry to become a positive one concurrently? - Eric
