On 12/23/2010 06:50 PM, Jeff Layton wrote: > 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. > Ah, ok. Got confused a bit trying to match the code with patch description. > 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. Agreed. > 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. > Sounds reasonable. -- Suresh Jayaraman -- 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
