4 fixes to cifs client, 2 for stable

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Merge tag '5.18-rc3-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6

Pull cifs fixes from Steve French:
 "Four fixes, two of them for stable:

   - fcollapse fix

   - reconnect lock fix

   - DFS oops fix

   - minor cleanup patch"

* tag '5.18-rc3-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: destage any unwritten data to the server before calling copychunk_write
  cifs: use correct lock type in cifs_reconnect()
  cifs: fix NULL ptr dereference in refresh_mounts()
  cifs: Use kzalloc instead of kmalloc/memset

fs/cifs/connect.c

@@ -534,12 +534,19 @@ int cifs_reconnect(struct TCP_Server_Info *server, bool mark_smb_session)
 {
 	/* If tcp session is not an dfs connection, then reconnect to last target server */
 	spin_lock(&cifs_tcp_ses_lock);
-	if (!server->is_dfs_conn || !server->origin_fullpath || !server->leaf_fullpath) {
+	if (!server->is_dfs_conn) {
 		spin_unlock(&cifs_tcp_ses_lock);
 		return __cifs_reconnect(server, mark_smb_session);
 	}
 	spin_unlock(&cifs_tcp_ses_lock);
 
+	mutex_lock(&server->refpath_lock);
+	if (!server->origin_fullpath || !server->leaf_fullpath) {
+		mutex_unlock(&server->refpath_lock);
+		return __cifs_reconnect(server, mark_smb_session);
+	}
+	mutex_unlock(&server->refpath_lock);
+
 	return reconnect_dfs_server(server);
 }
 #else
@@ -3675,9 +3682,11 @@ static void setup_server_referral_paths(struct mount_ctx *mnt_ctx)
 {
 	struct TCP_Server_Info *server = mnt_ctx->server;
 
+	mutex_lock(&server->refpath_lock);
 	server->origin_fullpath = mnt_ctx->origin_fullpath;
 	server->leaf_fullpath = mnt_ctx->leaf_fullpath;
 	server->current_fullpath = mnt_ctx->leaf_fullpath;
+	mutex_unlock(&server->refpath_lock);
 	mnt_ctx->origin_fullpath = mnt_ctx->leaf_fullpath = NULL;
 }
 

fs/cifs/dfs_cache.c

@@ -1422,11 +1422,13 @@ static int refresh_tcon(struct cifs_ses **sessions, struct cifs_tcon *tcon, bool
 	struct TCP_Server_Info *server = tcon->ses->server;
 
 	mutex_lock(&server->refpath_lock);
-	if (strcasecmp(server->leaf_fullpath, server->origin_fullpath))
+	if (server->origin_fullpath) {
+		if (server->leaf_fullpath && strcasecmp(server->leaf_fullpath,
+							server->origin_fullpath))
 			__refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, force_refresh);
-	mutex_unlock(&server->refpath_lock);
-
 		__refresh_tcon(server->origin_fullpath + 1, sessions, tcon, force_refresh);
+	}
+	mutex_unlock(&server->refpath_lock);
 
 	return 0;
 }
@@ -1530,11 +1532,14 @@ static void refresh_mounts(struct cifs_ses **sessions)
 		list_del_init(&tcon->ulist);
 
 		mutex_lock(&server->refpath_lock);
-		if (strcasecmp(server->leaf_fullpath, server->origin_fullpath))
+		if (server->origin_fullpath) {
+			if (server->leaf_fullpath && strcasecmp(server->leaf_fullpath,
+								server->origin_fullpath))
 				__refresh_tcon(server->leaf_fullpath + 1, sessions, tcon, false);
+			__refresh_tcon(server->origin_fullpath + 1, sessions, tcon, false);
+		}
 		mutex_unlock(&server->refpath_lock);
 
-		__refresh_tcon(server->origin_fullpath + 1, sessions, tcon, false);
 		cifs_put_tcon(tcon);
 	}
 }

fs/cifs/smb2ops.c

@@ -1858,9 +1858,17 @@ smb2_copychunk_range(const unsigned int xid,
 	int chunks_copied = 0;
 	bool chunk_sizes_updated = false;
 	ssize_t bytes_written, total_bytes_written = 0;
+	struct inode *inode;
 
 	pcchunk = kmalloc(sizeof(struct copychunk_ioctl), GFP_KERNEL);
 
+	/*
+	 * We need to flush all unwritten data before we can send the
+	 * copychunk ioctl to the server.
+	 */
+	inode = d_inode(trgtfile->dentry);
+	filemap_write_and_wait(inode->i_mapping);
+
 	if (pcchunk == NULL)
 		return -ENOMEM;
 

fs/cifs/transport.c

@@ -464,13 +464,12 @@ smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 		return -EIO;
 	}
 
-	tr_hdr = kmalloc(sizeof(*tr_hdr), GFP_NOFS);
+	tr_hdr = kzalloc(sizeof(*tr_hdr), GFP_NOFS);
 	if (!tr_hdr)
 		return -ENOMEM;
 
 	memset(&cur_rqst[0], 0, sizeof(cur_rqst));
 	memset(&iov, 0, sizeof(iov));
-	memset(tr_hdr, 0, sizeof(*tr_hdr));
 
 	iov.iov_base = tr_hdr;
 	iov.iov_len = sizeof(*tr_hdr);