[SMB3] Enable checking for continuous availability and persistent handle support
Validate "persistenthandles" and "nopersistenthandles" mount options against
the support the server claims in negotiate and tree connect SMB3 responses.
Signed-off-by: Steve French <steve.french@primarydata.com>
Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 9a9a543..bb35ae7 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2673,6 +2673,30 @@
cifs_dbg(FYI, "DFS disabled (%d)\n", tcon->Flags);
}
tcon->seal = volume_info->seal;
+ tcon->use_persistent = false;
+ /* check if SMB2 or later, CIFS does not support persistent handles */
+ if (volume_info->persistent) {
+ if (ses->server->vals->protocol_id == 0) {
+ cifs_dbg(VFS,
+ "SMB3 or later required for persistent handles\n");
+ rc = -EOPNOTSUPP;
+ goto out_fail;
+ } else if (ses->server->capabilities &
+ SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
+ tcon->use_persistent = true;
+ else /* persistent handles requested but not supported */ {
+ cifs_dbg(VFS,
+ "Persistent handles not supported on share\n");
+ rc = -EOPNOTSUPP;
+ goto out_fail;
+ }
+ } else if ((tcon->capabilities & SMB2_SHARE_CAP_CONTINUOUS_AVAILABILITY)
+ && (ses->server->capabilities & SMB2_GLOBAL_CAP_PERSISTENT_HANDLES)
+ && (volume_info->nopersistent == false)) {
+ cifs_dbg(FYI, "enabling persistent handles\n");
+ tcon->use_persistent = true;
+ }
+
/*
* We can have only one retry value for a connection to a share so for
* resources mounted more than once to the same server share the last
@@ -3521,6 +3545,12 @@
goto mount_fail_check;
}
+ if ((volume_info->persistent == true) && ((ses->server->capabilities &
+ SMB2_GLOBAL_CAP_PERSISTENT_HANDLES) == 0)) {
+ cifs_dbg(VFS, "persistent handles not supported by server\n");
+ rc = -EOPNOTSUPP;
+ goto mount_fail_check;
+ }
/* search for existing tcon to this server share */
tcon = cifs_get_tcon(ses, volume_info);
if (IS_ERR(tcon)) {