2012/7/16 Jeff Layton <jlayton@xxxxxxxxx>: > On Fri, 13 Jul 2012 17:12:51 +0400 > Pavel Shilovsky <piastryyy@xxxxxxxxx> wrote: > >> 2012/7/13 Pavel Shilovsky <piastryyy@xxxxxxxxx>: >> > Hi there! >> > >> > I faced with an interesting problem: >> > Windows 7 send lease break just after granted lease on open - so, we >> > don't have time to populate cifsFileInfo structure and can't determine >> > oplock break because we simply don't find appropriate fid. I think >> > this problem can be happen for CIFS/SMB2.0 too (e.g. if another client >> > opens the file just after us). >> > >> > So, what do you think about creating delegating the oplock break >> > processing to workqueue and return to demultiplex thread immideately? >> > It give us a small timeout itself and we can set another defined >> > timeout explicitly. >> > >> > -- >> > Best regards, >> > Pavel Shilovsky. >> >> I created a patch that fixes the problem for lease breaks - we can do >> smth similiar for oplock breaks too: >> >> http://git.altlinux.org/people/piastry/public/?p=cifs-2.6.git;a=commit;h=b918551247997057f4467dfc332d47c547449ddd >> > > What guarantee is there that this fid will be on the list by the time > the work runs? It seems to me that this just narrows the race window a > bit without fully closing it. Yes, nothing guarantees that this fid will be on the list - it's like a midterm fix. We really need to be sure that open/create call ends cifs_new_fileinfo before oplock break comes. We can round open/create calls with rw mutex: allow several open/create calls process in parallel (by holding read lock) but only one oplock break call can process in the one time (write lock). So, it's a bit tricky but can be commented as well: "read lock" - sending open request and populating cifsFileInfo structure "write lock" - oplock break processing -- Best regards, Pavel Shilovsky. -- 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
