On Mon, Oct 04, 2021 at 09:03:53AM +0800, Ian Kent wrote: > It's been reported that doing stress test for module insertion and > removal can result in an ENOENT from libkmod for a valid module. > > In kernfs_iop_lookup() a negative dentry is created if there's no kernfs > node associated with the dentry or the node is inactive. > > But inactive kernfs nodes are meant to be invisible to the VFS and > creating a negative dentry for these can have unexpected side effects > when the node transitions to an active state. > > The point of creating negative dentries is to avoid the expensive > alloc/free cycle that occurs if there are frequent lookups for kernfs > attributes that don't exist. So kernfs nodes that are not yet active > should not result in a negative dentry being created so when they > transition to an active state VFS lookups can create an associated > dentry is a natural way. > > It's also been reported that https://github.com/osandov/blktests.git > test block/001 hangs during the test. It was suggested that recent > changes to blktests might have caused it but applying this patch > resolved the problem without change to blktests. Looks sane, but which tree should it go through? I can pick it, but I've no idea if anybody already has kernfs work in their trees...
