smb: client: prevent lease breaks of cached parents when opening children

In SMB2_open_init(), lookup for a cached parent of oparms->path
(child/target) and set ParentLeaseKey in lease context if found.

Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>

3 files changed, 58 insertions, 60 deletions

diff --git a/fs/smb/client/cached_dir.c b/fs/smb/client/cached_dir.c
index ad9c95c20c4e..0acaed4a2a34 100644
--- a/fs/smb/client/cached_dir.c
+++ b/fs/smb/client/cached_dir.c
@@ -209,7 +209,6 @@ int open_cached_dir(unsigned int xid, struct cifs_tcon *tcon, const char *path,
 	struct cached_fids *cfids;
 	const char *npath;
 	int retries = 0, cur_sleep = 1;
-	__le32 lease_flags = 0;
 	bool has_info;
 
 	if (cifs_sb->root == NULL)
@@ -293,25 +292,6 @@ replay_again:
 			rc = -ENOENT;
 			goto out_err;
 		}
-		if (dentry->d_parent && server->dialect >= SMB30_PROT_ID) {
-			struct cached_fid *parent_cfid;
-
-			spin_lock(&cfids->cfid_list_lock);
-			list_for_each_entry(parent_cfid, &cfids->entries, entry) {
-				if (parent_cfid->dentry == dentry->d_parent) {
-					cifs_dbg(FYI, "found a parent cached file handle\n");
-					if (cfid_is_valid(parent_cfid)) {
-						lease_flags
-							|= SMB2_LEASE_FLAG_PARENT_LEASE_KEY_SET_LE;
-						memcpy(pfid->parent_lease_key,
-						       parent_cfid->fid.lease_key,
-						       SMB2_LEASE_KEY_SIZE);
-					}
-					break;
-				}
-			}
-			spin_unlock(&cfids->cfid_list_lock);
-		}
 	}
 
 	/*
@@ -343,7 +323,6 @@ replay_again:
 				   FILE_READ_EA,
 		.disposition = FILE_OPEN,
 		.fid = pfid,
-		.lease_flags = lease_flags,
 		.replay = !!(retries),
 	};
 
diff --git a/fs/smb/client/dir.c b/fs/smb/client/dir.c
index 2c6450e1c97c..23412156d12a 100644
--- a/fs/smb/client/dir.c
+++ b/fs/smb/client/dir.c
@@ -190,9 +190,7 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
 	int disposition;
 	struct TCP_Server_Info *server = tcon->ses->server;
 	struct cifs_open_parms oparms;
-	struct cached_fid *parent_cfid = NULL;
 	int rdwr_for_fscache = 0;
-	__le32 lease_flags = 0;
 
 	*oplock = 0;
 	if (tcon->ses->server->oplocks)
@@ -314,28 +312,7 @@ static int cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned
 	if (!tcon->unix_ext && (mode & S_IWUGO) == 0)
 		create_options |= CREATE_OPTION_READONLY;
 
-
 retry_open:
-	if (tcon->cfids && direntry->d_parent && server->dialect >= SMB30_PROT_ID) {
-		parent_cfid = NULL;
-		spin_lock(&tcon->cfids->cfid_list_lock);
-		list_for_each_entry(parent_cfid, &tcon->cfids->entries, entry) {
-			if (parent_cfid->dentry == direntry->d_parent) {
-				cifs_dbg(FYI, "found a parent cached file handle\n");
-				if (cfid_is_valid(parent_cfid)) {
-					lease_flags
-						|= SMB2_LEASE_FLAG_PARENT_LEASE_KEY_SET_LE;
-					memcpy(fid->parent_lease_key,
-					       parent_cfid->fid.lease_key,
-					       SMB2_LEASE_KEY_SIZE);
-					parent_cfid->dirents.is_valid = false;
-				}
-				break;
-			}
-		}
-		spin_unlock(&tcon->cfids->cfid_list_lock);
-	}
-
 	oparms = (struct cifs_open_parms) {
 		.tcon = tcon,
 		.cifs_sb = cifs_sb,
@@ -344,7 +321,6 @@ retry_open:
 		.disposition = disposition,
 		.path = full_path,
 		.fid = fid,
-		.lease_flags = lease_flags,
 		.mode = mode,
 	};
 	rc = server->ops->open(xid, &oparms, oplock, buf);
diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 07ba61583114..f54029ee2466 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -2419,7 +2419,8 @@ add_lease_context(struct TCP_Server_Info *server,
 	if (iov[num].iov_base == NULL)
 		return -ENOMEM;
 	iov[num].iov_len = server->vals->create_lease_size;
-	req->RequestedOplockLevel = SMB2_OPLOCK_LEVEL_LEASE;
+	/* keep the requested oplock level in case of just setting ParentLeaseKey */
+	req->RequestedOplockLevel = *oplock;
 	*num_iovec = num + 1;
 	return 0;
 }
@@ -3001,6 +3002,45 @@ err_free_path:
 	return rc;
 }
 
+/*
+ * Set ParentLeaseKey in @oparms if path's parent is cached.
+ *
+ * MS-SMB2 "Product Behavior" says Windows only checks/sets ParentLeaseKey when a lease is
+ * requested for the child/target.
+ * However, practically, adding the lease context with ParentLeaseKey set, even with oplock none,
+ * works fine.
+ *
+ * Ref: MS-SMB2 3.3.5.9 and MS-FSA 2.1.5.1
+ *
+ * Return: 0 if ParentLeaseKey was set, -errno otherwise
+ */
+static int add_parent_leasekey(struct cached_fids *cfids, struct cifs_open_parms *oparms)
+{
+       struct cached_fid *cfid;
+
+       if (!cfids || !oparms || !*oparms->path)
+               return -EINVAL;
+
+       /*
+	* We only have RH caching for cached dirs, so we must let the lease break happen for any
+	* operation that creates/removes entries.
+	*/
+       if (oparms->disposition != FILE_OPEN || oparms->desired_access == DELETE)
+	       return -EOPNOTSUPP;
+
+       cfid = find_cached_dir(cfids, oparms->path, CFID_LOOKUP_PARENT);
+       if (!cfid)
+               return -ENOENT;
+
+       cifs_dbg(FYI, "%s: found cached parent for path: %s\n", __func__, oparms->path);
+
+       memcpy(oparms->fid->parent_lease_key, cfid->fid.lease_key, SMB2_LEASE_KEY_SIZE);
+       oparms->lease_flags |= SMB2_LEASE_FLAG_PARENT_LEASE_KEY_SET_LE;
+       close_cached_dir(cfid);
+
+       return 0;
+}
+
 int
 SMB2_open_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
 	       struct smb_rqst *rqst, __u8 *oplock,
@@ -3077,24 +3117,27 @@ SMB2_open_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
 	iov[1].iov_len = uni_path_len;
 	iov[1].iov_base = path;
 
-	if ((!server->oplocks) || (tcon->no_lease))
+	if (!server->oplocks || tcon->no_lease)
 		*oplock = SMB2_OPLOCK_LEVEL_NONE;
 
-	if (!(server->capabilities & SMB2_GLOBAL_CAP_LEASING) ||
-	    *oplock == SMB2_OPLOCK_LEVEL_NONE)
-		req->RequestedOplockLevel = *oplock;
-	else if (!(server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING) &&
-		  (oparms->create_options & CREATE_NOT_FILE))
-		req->RequestedOplockLevel = *oplock; /* no srv lease support */
-	else {
-		rc = add_lease_context(server, req, iov, &n_iov,
-				       oparms->fid->lease_key, oplock,
-				       oparms->fid->parent_lease_key,
-				       oparms->lease_flags);
-		if (rc)
-			return rc;
+	if (server->capabilities & SMB2_GLOBAL_CAP_LEASING) {
+		rc = -EOPNOTSUPP;
+
+		if (server->capabilities & SMB2_GLOBAL_CAP_DIRECTORY_LEASING)
+			rc = add_parent_leasekey(tcon->cfids, oparms);
+
+		if (!rc || *oplock != SMB2_OPLOCK_LEVEL_NONE) {
+			rc = add_lease_context(server, req, iov, &n_iov,
+					       oparms->fid->lease_key, oplock,
+					       oparms->fid->parent_lease_key,
+					       oparms->lease_flags);
+			if (rc)
+				return rc;
+		}
 	}
 
+	req->RequestedOplockLevel = *oplock;
+
 	if (*oplock == SMB2_OPLOCK_LEVEL_BATCH) {
 		rc = add_durable_context(iov, &n_iov, oparms,
 					tcon->use_persistent);