• NeilBrown's avatar
    NFSv4: add flock_owner to open context · 532d4def
    NeilBrown authored
    An open file description (struct file) in a given process can be
    associated with two different lock owners.
    
    It can have a Posix lock owner which will be different in each process
    that has a fd on the file.
    It can have a Flock owner which will be the same in all processes.
    
    When searching for a lock stateid to use, we need to consider both of these
    owners
    
    So add a new "flock_owner" to the "nfs_open_context" (of which there
    is one for each open file description).
    
    This flock_owner does not need to be reference-counted as there is a
    1-1 relation between 'struct file' and nfs open contexts,
    and it will never be part of a list of contexts.  So there is no need
    for a 'flock_context' - just the owner is enough.
    
    The io_count included in the (Posix) lock_context provides no
    guarantee that all read-aheads that could use the state have
    completed, so not supporting it for flock locks in not a serious
    problem.  Synchronization between flock and read-ahead can be added
    later if needed.
    
    When creating an open_context for a non-openning create call, we don't have
    a 'struct file' to pass in, so the lock context gets initialized with
    a NULL owner, but this will never be used.
    
    The flock_owner is not used at all in this patch, that will come later.
    Acked-by: default avatarJeff Layton <jlayton@redhat.com>
    Signed-off-by: default avatarNeilBrown <neilb@suse.com>
    Reviewed-by: default avatarJeff Layton <jlayton@redhat.com>
    Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
    532d4def
nfs4proc.c 253 KB