ksmbd: retry iterate_dir in smb2_query_dir

Some file systems do not ensure that the single call of iterate_dir
reaches the end of the directory. For example, FUSE fetches entries from
a daemon using 4KB buffer and stops fetching if entries exceed 4KB.
Pattern searching on FUSE, the file located after the 4KB can not be
found and STATUS_NO_SUCH_FILE will be returned.

Signed-off-by: Hobin Woo <[email protected]>
Signed-off-by: Namjae Jeon <[email protected]>

smb2pdu.c

@@ -4443,6 +4443,7 @@ static int __query_dir(struct dir_context *ctx, const char *name, int namlen,
 #else
 		return 0;
 #endif
+	d_info->num_scan++;
 	if (ksmbd_share_veto_filename(priv->work->tcon->share_conf, name))
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 1, 0)
 		return true;
@@ -4637,7 +4638,15 @@ int smb2_query_dir(struct ksmbd_work *work)
 	dir_fp->readdir_data.private		= &query_dir_private;
 	set_ctx_actor(&dir_fp->readdir_data.ctx, __query_dir);
 
+again:
 	rc = iterate_dir(dir_fp->filp, &dir_fp->readdir_data.ctx);
+	/*
+	 * num_entry can be 0 if the directory iteration stops before reaching
+	 * the end of the directory and no file is matched with the search
+	 * pattern.
+	 */
+	if (rc >= 0 && !d_info.num_entry && d_info.num_scan)
+		goto again;
 	/*
 	 * req->OutputBufferLength is too small to contain even one entry.
 	 * In this case, it immediately returns OutputBufferLength 0 to client.

vfs.h

@@ -85,6 +85,7 @@ struct ksmbd_dir_info {
 	char		*rptr;
 	int		name_len;
 	int		out_buf_len;
+	int		num_scan;
 	int		num_entry;
 	int		data_count;
 	int		last_entry_offset;