This took longer that I had wanted, due to various reasons - sorry. And I'm now posting it in a merge window, which is not ideal. I don't expect it to be included in this merge window and I won't be at all impatient for review, but I didn't want to delay it further. Testing found some problems, particularly the need to use locks_copy_lock in NFS. And there was a small thinko in there that effectively removed all the speed gains :-( But this version: - shows excellent scalability with lots of threads on lots of CPUs contending on a single file - avoids the problems that Bruce found - seems to work. Thanks, NeilBrown --- NeilBrown (9): fs/locks: rename some lists and pointers. fs/locks: split out __locks_wake_up_blocks(). NFS: use locks_copy_lock() to copy locks. fs/locks: allow a lock request to block other requests. fs/locks: always delete_block after waiting. fs/locks: change all *_conflict() functions to return bool. fs/locks: create a tree of dependent requests. locks: merge posix_unblock_lock() and locks_delete_block() VFS: locks: remove unnecessary white space. fs/cifs/file.c | 4 - fs/lockd/svclock.c | 2 fs/locks.c | 231 ++++++++++++++++++++++----------------- fs/nfs/nfs4proc.c | 6 + fs/nfsd/nfs4state.c | 6 + include/linux/fs.h | 11 +- include/trace/events/filelock.h | 16 +-- 7 files changed, 153 insertions(+), 123 deletions(-) -- Signature