CIFS: Close cached root handle only if it has a lease

SMB2_tdis() checks if a root handle is valid in order to decide
whether it needs to close the handle or not. However if another
thread has reference for the handle, it may end up with putting
the reference twice. The extra reference that we want to put
during the tree disconnect is the reference that has a directory
lease. So, track the fact that we have a directory lease and
close the handle only in that case.

Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 18 insertions, 1 deletions

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index a5c96bc522cb..6250370c1170 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -616,6 +616,7 @@ smb2_close_cached_fid(struct kref *ref)
 			   cfid->fid->volatile_fid);
 		cfid->is_valid = false;
 		cfid->file_all_info_is_valid = false;
+		cfid->has_lease = false;
 	}
 }
 
@@ -626,13 +627,28 @@ void close_shroot(struct cached_fid *cfid)
 	mutex_unlock(&cfid->fid_mutex);
 }
 
+void close_shroot_lease_locked(struct cached_fid *cfid)
+{
+	if (cfid->has_lease) {
+		cfid->has_lease = false;
+		kref_put(&cfid->refcount, smb2_close_cached_fid);
+	}
+}
+
+void close_shroot_lease(struct cached_fid *cfid)
+{
+	mutex_lock(&cfid->fid_mutex);
+	close_shroot_lease_locked(cfid);
+	mutex_unlock(&cfid->fid_mutex);
+}
+
 void
 smb2_cached_lease_break(struct work_struct *work)
 {
 	struct cached_fid *cfid = container_of(work,
 				struct cached_fid, lease_break);
 
-	close_shroot(cfid);
+	close_shroot_lease(cfid);
 }
 
 /*
@@ -773,6 +789,7 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon, struct cifs_fid *pfid)
 	/* BB TBD check to see if oplock level check can be removed below */
 	if (o_rsp->OplockLevel == SMB2_OPLOCK_LEVEL_LEASE) {
 		kref_get(&tcon->crfid.refcount);
+		tcon->crfid.has_lease = true;
 		smb2_parse_contexts(server, o_rsp,
 				&oparms.fid->epoch,
 				oparms.fid->lease_key, &oplock, NULL);