On 2018-02-17, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: >> dentry_kill() calls both dentry_lock_inode() and lock_parent() in the >> common case. So by changing the semantics of lock_parent(), I am >> removing two "recheck in case I dropped" in the common case rather >> than just the one you pointed out. > > Ok, that would be lovely, but doesn't that end up being a nasty patch? After reading your initial feedback my idea was to change both lock_parent() and dentry_lock_inode() to not only communicate _if_ the lock was successful, but also if d_lock was dropped in the process. (For example, with a tristate rather than boolean return value.) Then callers would know if they needed to recheck the dentry contents. > So it may be that my dislike of the "re-check after possibly dropping > the lock" is not really about the re-checking, but about just how it > made that function look much more complicated. I understand what you are saying and I appreciate the comments. I will code up some variations for myself and try to pick the one that is the least complicated for my v2. John Ogness
