smb3: allow deferred close timeout to be configurable

Deferred close can be a very useful feature for allowing
caching data for read, and for minimizing the number of
reopens needed for a file that is repeatedly opened and
close but there are workloads where its default (1 second,
similar to actimeo/acregmax) is much too small.

Allow the user to configure the amount of time we can
defer sending the final smb3 close when we have a
handle lease on the file (rather than forcing it to depend
on value of actimeo which is often unrelated, and less safe).

Adds new mount parameter "closetimeo=" which is the maximum
number of seconds we can wait before sending an SMB3
close when we have a handle lease for it.  Default value
also is set to slightly larger at 5 seconds (although some
other clients use larger default this should still help).

Suggested-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 7f205a9a2de4..9111c025bcb8 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2681,6 +2681,8 @@ compare_mount_options(struct super_block *sb, struct cifs_mnt_data *mnt_data)
 		return 0;
 	if (old->ctx->acdirmax != new->ctx->acdirmax)
 		return 0;
+	if (old->ctx->closetimeo != new->ctx->closetimeo)
+		return 0;
 
 	return 1;
 }