CIFS: Fix fast lease break after open problem

Now we walk though cifsFileInfo's list for every incoming lease
break and look for an equivalent there. That approach misses lease
breaks that come just after an open response - we don't have time
to populate new cifsFileInfo structure to the list. Fix this by
adding new list of pending opens and look for a lease there if we
didn't find it in the list of cifsFileInfo structures.

Signed-off-by: Pavel Shilovsky <pshilovsky@etersoft.ru>
Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 69 insertions, 5 deletions

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index 3a7f8bd5127d..cd31715f03f4 100644
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -389,6 +389,27 @@ __u8 smb2_map_lease_to_oplock(__le32 lease_state)
 	return 0;
 }
 
+struct smb2_lease_break_work {
+	struct work_struct lease_break;
+	struct tcon_link *tlink;
+	__u8 lease_key[16];
+	__le32 lease_state;
+};
+
+static void
+cifs_ses_oplock_break(struct work_struct *work)
+{
+	struct smb2_lease_break_work *lw = container_of(work,
+				struct smb2_lease_break_work, lease_break);
+	int rc;
+
+	rc = SMB2_lease_break(0, tlink_tcon(lw->tlink), lw->lease_key,
+			      lw->lease_state);
+	cFYI(1, "Lease release rc %d", rc);
+	cifs_put_tlink(lw->tlink);
+	kfree(lw);
+}
+
 static bool
 smb2_is_valid_lease_break(char *buffer, struct TCP_Server_Info *server)
 {
@@ -398,6 +419,19 @@ smb2_is_valid_lease_break(char *buffer, struct TCP_Server_Info *server)
 	struct cifs_tcon *tcon;
 	struct cifsInodeInfo *cinode;
 	struct cifsFileInfo *cfile;
+	struct cifs_pending_open *open;
+	struct smb2_lease_break_work *lw;
+	bool found;
+	int ack_req = rsp->Flags & SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED;
+
+	lw = kmalloc(sizeof(struct smb2_lease_break_work), GFP_KERNEL);
+	if (!lw) {
+		cERROR(1, "Memory allocation failed during lease break check");
+		return false;
+	}
+
+	INIT_WORK(&lw->lease_break, cifs_ses_oplock_break);
+	lw->lease_state = rsp->NewLeaseState;
 
 	cFYI(1, "Checking for lease break");
 
@@ -405,28 +439,29 @@ smb2_is_valid_lease_break(char *buffer, struct TCP_Server_Info *server)
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each(tmp, &server->smb_ses_list) {
 		ses = list_entry(tmp, struct cifs_ses, smb_ses_list);
+
+		spin_lock(&cifs_file_list_lock);
 		list_for_each(tmp1, &ses->tcon_list) {
 			tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 
 			cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
-			spin_lock(&cifs_file_list_lock);
 			list_for_each(tmp2, &tcon->openFileList) {
 				cfile = list_entry(tmp2, struct cifsFileInfo,
-						     tlist);
+						   tlist);
 				cinode = CIFS_I(cfile->dentry->d_inode);
 
 				if (memcmp(cinode->lease_key, rsp->LeaseKey,
 					   SMB2_LEASE_KEY_SIZE))
 					continue;
 
+				cFYI(1, "found in the open list");
 				cFYI(1, "lease key match, lease break 0x%d",
 				     le32_to_cpu(rsp->NewLeaseState));
 
 				smb2_set_oplock_level(cinode,
 				  smb2_map_lease_to_oplock(rsp->NewLeaseState));
 
-				if (rsp->Flags &
-				    SMB2_NOTIFY_BREAK_LEASE_FLAG_ACK_REQUIRED)
+				if (ack_req)
 					cfile->oplock_break_cancelled = false;
 				else
 					cfile->oplock_break_cancelled = true;
@@ -437,10 +472,39 @@ smb2_is_valid_lease_break(char *buffer, struct TCP_Server_Info *server)
 				spin_unlock(&cifs_tcp_ses_lock);
 				return true;
 			}
-			spin_unlock(&cifs_file_list_lock);
+
+			found = false;
+			list_for_each_entry(open, &tcon->pending_opens, olist) {
+				if (memcmp(open->lease_key, rsp->LeaseKey,
+					   SMB2_LEASE_KEY_SIZE))
+					continue;
+
+				if (!found && ack_req) {
+					found = true;
+					memcpy(lw->lease_key, open->lease_key,
+					       SMB2_LEASE_KEY_SIZE);
+					lw->tlink = cifs_get_tlink(open->tlink);
+					queue_work(cifsiod_wq,
+						   &lw->lease_break);
+				}
+
+				cFYI(1, "found in the pending open list");
+				cFYI(1, "lease key match, lease break 0x%d",
+				     le32_to_cpu(rsp->NewLeaseState));
+
+				open->oplock =
+				  smb2_map_lease_to_oplock(rsp->NewLeaseState);
+			}
+			if (found) {
+				spin_unlock(&cifs_file_list_lock);
+				spin_unlock(&cifs_tcp_ses_lock);
+				return true;
+			}
 		}
+		spin_unlock(&cifs_file_list_lock);
 	}
 	spin_unlock(&cifs_tcp_ses_lock);
+	kfree(lw);
 	cFYI(1, "Can not process lease break - no lease matched");
 	return false;
 }