On Wed, 13 Aug 2025, Al Viro wrote: > On Tue, Aug 12, 2025 at 12:25:07PM +1000, NeilBrown wrote: > > A few callers operate on a dentry which they already have - unlike the > > normal case where a lookup proceeds an operation. > > > > For these callers dentry_lookup_continue() is provided where other > > callers would use dentry_lookup(). The call will fail if, after the > > lock was gained, the child is no longer a child of the given parent. > > > > There are a couple of callers that want to lock a dentry in whatever > > its current parent is. For these a NULL parent can be passed, in which > > case ->d_parent is used. In this case the call cannot fail. > > > > The idea behind the name is that the actual lookup occurred some time > > ago, and now we are continuing with an operation on the dentry. > > > > When the operation completes done_dentry_lookup() must be called. An > > extra reference is taken when the dentry_lookup_continue() call succeeds > > and will be dropped by done_dentry_lookup(). > > > > This will be used in smb/server, ecryptfs, and overlayfs, each of which > > have their own lock_parent() or parent_lock() or similar; and a few > > other places which lock the parent but don't check if the parent is > > still correct (often because rename isn't supported so parent cannot be > > incorrect). > > I would really like the see the conversion of these callers. You are > asking for a buy-in for a primitive with specific semantics; that's > hard to review without seeing how it will be used. >
All, or just some? I use dentry_lookup_continue() in: cachefiles: 4 times ecryptfs: once overlayfs: twice smb/server: once apparmor: once Maybe I could include all in the one patch... NeilBrown
