On Thu, 23 Dec 2010 16:01:08 +0530 Suresh Jayaraman <sjayaraman@xxxxxxx> wrote: > On 12/17/2010 08:38 PM, Jeff Layton wrote: > > If the server isn't responding to echoes, we don't want to leave tasks > > hung waiting for it to reply. At that point, we'll want to reconnect > > so that soft mounts can return an error to userspace quickly. > > > > If the client hasn't received a reply after 3 echo intervals, assume > > that the transport is down and attempt to reconnect the socket. > > > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > > --- > > fs/cifs/connect.c | 23 +++++++++++++++++++---- > > 1 files changed, 19 insertions(+), 4 deletions(-) > > > > diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c > > index 20f6eda..2ad3c67 100644 > > --- a/fs/cifs/connect.c > > +++ b/fs/cifs/connect.c > > @@ -55,6 +55,9 @@ > > /* SMB echo "timeout" -- FIXME: tunable? */ > > #define SMB_ECHO_INTERVAL (60 * HZ) > > > > +/* reconnect if no response from server in this time period */ > > +#define UNRESPONSIVE_SERVER_TIMEOUT (5 * SMB_ECHO_INTERVAL) > > + > > It's not clear to me why is this timeout is set to be > 5 * SMB_ECHO_INTERVAL? > My bad... I should have updated the patch description. When testing this I experimented with a range of 2 to 5 times. There is no "correct" value for this. It really comes down to a judgement call. Reducing that value means that you'll return an error to the caller more quickly on a soft mount timeout occurs. The downside is that you'll issue reconnects more frequently when there's a temporary network partition. I tend to think that we're better off running with a larger value for this (around 5*). Reconnects are terribly expensive and lock reclaimation in Linux cifs is non-existent. Avoiding reconnects as much as possible is preferable so making this as high as we can get away with is a good thing. That said, I'm open to suggestions on this. I think we shouldn't go below 3*, and above 5* is probably too much. We could eventually make it tunable, but we still need a default. I don't think it should be a mount option since it's a per-socket setting (mounts with different timeouts wouldn't be able to share sockets), so maybe a module option would be best. Thoughts? -- Jeff Layton <jlayton@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
