On Wed, 2013-02-27 at 16:44 -0600, Dave Chiluk wrote: > On 02/27/2013 04:40 PM, Steve French wrote: > > On Wed, Feb 27, 2013 at 4:24 PM, Dave Chiluk <dave.chiluk@xxxxxxxxxxxxx> wrote: > >> On 02/27/2013 10:34 AM, Jeff Layton wrote: > >>> On Wed, 27 Feb 2013 12:06:14 +0100 > >>> "Stefan (metze) Metzmacher" <metze@xxxxxxxxx> wrote: > >>> > >>>> Hi Dave, > >>>> > >>>>> When messages are currently in queue awaiting a response, decrease amount of > >>>>> time before attempting cifs_reconnect to SMB_MAX_RTT = 10 seconds. The current > >>>>> wait time before attempting to reconnect is currently 2*SMB_ECHO_INTERVAL(120 > >>>>> seconds) since the last response was recieved. This does not take into account > >>>>> the fact that messages waiting for a response should be serviced within a > >>>>> reasonable round trip time. > >>>> > >>>> Wouldn't that mean that the client will disconnect a good connection, > >>>> if the server doesn't response within 10 seconds? > >>>> Reads and Writes can take longer than 10 seconds... > >>>> > >>> > >>> Where does this magic value of 10s come from? Note that a slow server > >>> can take *minutes* to respond to writes that are long past the EOF. > >> It comes from the desire to decrease the reconnection delay to something > >> better than a random number between 60 and 120 seconds. I am not > >> committed to this number, and it is open for discussion. Additionally > >> if you look closely at the logic it's not 10 seconds per request, but > >> actually when requests have been in flight for more than 10 seconds make > >> sure we've heard from the server in the last 10 seconds. > >> > >> Can you explain more fully your use case of writes that are long past > >> the EOF? Perhaps with a test-case or script that I can test? As far as > >> I know writes long past EOF will just result in a sparse file, and > >> return in a reasonable round trip time *(that's at least what I'm seeing > >> with my testing). dd if=/dev/zero of=/mnt/cifs/a bs=1M count=100 > >> seek=100000, starts receiving responses from the server in about .05 > >> seconds with subsequent responses following at roughly .002-.01 second > >> intervals. This is well within my 10 second value. > > > > Note that not all Linux file systems support sparse files and > > certainly there are cifs servers running on operating systems other > > than Linux which have popular file systems which don't support sparse > > files (e.g. FAT32 but there are many others) - in any case, writes > > after end of file can take a LONG time if sparse files are not > > supported and I don't know a good way for the client to know that > > attribute of the server file system ahead of time (although we could > > attempt to set the sparse flag, servers can and do lie) > > > > It doesn't matter how long it takes for the entire operation to > complete, just so long as the server acks something in less than 10 > seconds. Now the question becomes, is there an OS out there that > doesn't ack the request or doesn't ack the progress regularly. IIRC older samba servers were fully synchronous and wouldn't reply to anything while processing an operation. I am sure you can still find old code bases in older (and slow) appliances out there. Simo. -- Simo Sorce Samba Team GPL Compliance Officer <simo@xxxxxxxxx> Principal Software Engineer at Red Hat, Inc. <simo@xxxxxxxxxx> -- 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
