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authorSachin Prabhu <sprabhu@redhat.com>2017-04-16 20:37:24 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-04-27 09:09:31 +0200
commitf8fe51c86583ccb38263277ee471f77053a9482a (patch)
tree9d1f1073e8d76493996816256c21cb4fc53eea3c
parenta2a67e53f92f9a3b5d94671b17b043eb56ec79ab (diff)
cifs: Do not send echoes before Negotiate is complete
commit 62a6cfddcc0a5313e7da3e8311ba16226fe0ac10 upstream. commit 4fcd1813e640 ("Fix reconnect to not defer smb3 session reconnect long after socket reconnect") added support for Negotiate requests to be initiated by echo calls. To avoid delays in calling echo after a reconnect, I added the patch introduced by the commit b8c600120fc8 ("Call echo service immediately after socket reconnect"). This has however caused a regression with cifs shares which do not have support for echo calls to trigger Negotiate requests. On connections which need to call Negotiation, the echo calls trigger an error which triggers a reconnect which in turn triggers another echo call. This results in a loop which is only broken when an operation is performed on the cifs share. For an idle share, it can DOS a server. The patch uses the smb_operation can_echo() for cifs so that it is called only if connection has been already been setup. kernel bz: 194531 Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Tested-by: Jonathan Liu <net147@gmail.com> Acked-by: Pavel Shilovsky <pshilov@microsoft.com> Signed-off-by: Steve French <smfrench@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/cifs/smb1ops.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index fc537c29044e..87b87e091e8e 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -1015,6 +1015,15 @@ cifs_dir_needs_close(struct cifsFileInfo *cfile)
return !cfile->srch_inf.endOfSearch && !cfile->invalidHandle;
}
+static bool
+cifs_can_echo(struct TCP_Server_Info *server)
+{
+ if (server->tcpStatus == CifsGood)
+ return true;
+
+ return false;
+}
+
struct smb_version_operations smb1_operations = {
.send_cancel = send_nt_cancel,
.compare_fids = cifs_compare_fids,
@@ -1049,6 +1058,7 @@ struct smb_version_operations smb1_operations = {
.get_dfs_refer = CIFSGetDFSRefer,
.qfs_tcon = cifs_qfs_tcon,
.is_path_accessible = cifs_is_path_accessible,
+ .can_echo = cifs_can_echo,
.query_path_info = cifs_query_path_info,
.query_file_info = cifs_query_file_info,
.get_srv_inum = cifs_get_srv_inum,