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, 2 deletions

diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 42f2639a1a66..2c5eae7d31f4 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -964,12 +964,12 @@ int cifs_close(struct inode *inode, struct file *file)
 				 * So, Increase the ref count to avoid use-after-free.
 				 */
 				if (!mod_delayed_work(deferredclose_wq,
-						&cfile->deferred, cifs_sb->ctx->acregmax))
+						&cfile->deferred, cifs_sb->ctx->closetimeo))
 					cifsFileInfo_get(cfile);
 			} else {
 				/* Deferred close for files */
 				queue_delayed_work(deferredclose_wq,
-						&cfile->deferred, cifs_sb->ctx->acregmax);
+						&cfile->deferred, cifs_sb->ctx->closetimeo);
 				cfile->deferred_close_scheduled = true;
 				spin_unlock(&cinode->deferred_lock);
 				return 0;