On Sun, Sep 12, 2010 at 7:15 PM, Jeff Layton <jlayton@xxxxxxxxx> wrote: > On Sun, 12 Sep 2010 16:19:46 -0500 > Steve French <smfrench@xxxxxxxxx> wrote: > >> On Sun, Sep 12, 2010 at 9:55 AM, Pavel Shilovsky <piastryyy@xxxxxxxxx> wrote: >> > 2010/9/12 Jeff Layton <jlayton@xxxxxxxxx>: >> >> That's just because our client is primitive in this regard. When an >> >> oplock break comes in, it always drops the entire oplock rather than >> >> trying to downgrade it. >> >> >> >> Notice that when the client sends the "reply" that it's actually a >> >> request. The client never sends an actual "response" to an oplock >> >> break. What it does is send a new LOCKING_ANDX request to the server >> >> with a Lock Type of oplock break (0x02) and an oplock level of 0. >> >> >> >> My interpretation has always been that this "response" from the client >> >> tells the server what new oplock level the client has elected to take. >> >> In this case, it elected to drop the lock altogether so the server has >> >> no need to send a new oplock break. >> > >> > You can find the code (misc.c, is_valid_oplock_break call) that >> > downgrades the oplock for the client according to the field >> > NewOplockLevel in Oplock Break sent by the server. But then you can >> > see that in cifs_oplock_break call (file.c) the client simply sends >> > acknowledge without setting any OplockLevel specific things. >> >> We already downgrade olocks. I don't think we have seen problems with the >> downgrade from "cache everything" to "cache only reads" - I don't think >> the client "response" to the oplock downgrade has to set additional flags in >> the "response" to the oplock break. >> > > If the server doesn't pay attention to that field, then Pavel is > correct and this is a server bug. > > Is it legitimate for the client to send an "oplock break" on its own > without the server requesting it first? No - but I am curious what happens :) > If so, is the oplock level > field also ignored? How does the server match up an oplock break > "request" to the "response"? > > It might be good to ask this on samba-technical (and maybe to ask MS). As this only takes two clients this is fairly easy to test (and prove Windows to Windows behavior). -- Thanks, Steve -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
