• Jeff Layton's avatar
    nfs: allow blocking locks to be awoken by lock callbacks · a1d617d8
    Jeff Layton authored
    Add a waitqueue head to the client structure. Have clients set a wait
    on that queue prior to requesting a lock from the server. If the lock
    is blocked, then we can use that to wait for wakeups.
    
    Note that we do need to do this "manually" since we need to set the
    wait on the waitqueue prior to requesting the lock, but requesting a
    lock can involve activities that can block.
    
    However, only do that for NFSv4.1 locks, either by compiling out
    all of the waitqueue handling when CONFIG_NFS_V4_1 is disabled, or
    skipping all of it at runtime if we're dealing with v4.0, or v4.1
    servers that don't send lock callbacks.
    
    Note too that even when we expect to get a lock callback, RFC5661
    section 20.11.4 is pretty clear that we still need to poll for them,
    so we do still sleep on a timeout. We do however always poll at the
    longest interval in that case.
    Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
    [Anna: nfs4_retry_setlk() "status" should default to -ERESTARTSYS]
    Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
    a1d617d8
nfs4client.c 33.8 KB