From patchwork Thu May 17 14:35:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Aur=C3=A9lien_Aptel?= X-Patchwork-Id: 10406867 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 7F47F60247 for ; Thu, 17 May 2018 14:35:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6944A201BC for ; Thu, 17 May 2018 14:35:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5D69428535; Thu, 17 May 2018 14:35:20 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00, MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8E87C201BC for ; Thu, 17 May 2018 14:35:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752009AbeEQOfS (ORCPT ); Thu, 17 May 2018 10:35:18 -0400 Received: from mx2.suse.de ([195.135.220.15]:43563 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751533AbeEQOfR (ORCPT ); Thu, 17 May 2018 10:35:17 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 487FAAE76; Thu, 17 May 2018 14:35:16 +0000 (UTC) From: Aurelien Aptel To: linux-cifs@vger.kernel.org Cc: smfrench@gmail.com, Aurelien Aptel , Paulo Alcantara Subject: [PATCH v1 1/1] smb2: fix missing files in root share directory listing Date: Thu, 17 May 2018 16:35:07 +0200 Message-Id: <20180517143507.2545-1-aaptel@suse.com> X-Mailer: git-send-email 2.13.6 Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When mounting a Windows share that is the root of a drive (eg. C$) the server does not return . and .. directory entries. This results in the smb2 code path erroneously skipping the 2 first entries. Pseudo-code of the readdir() code path: cifs_readdir(struct file, struct dir_context) initiate_cifs_search <-- if no reponse cached yet server->ops->query_dir_first dir_emit_dots dir_emit <-- adds "." and ".." if we're at pos=0 find_cifs_entry initiate_cifs_search <-- if pos < start of current response (restart search) server->ops->query_dir_next <-- if pos > end of current response (fetch next search res) for(...) <-- loops over cur response entries starting at pos cifs_filldir <-- skip . and .., emit entry cifs_fill_dirent dir_emit pos++ A) dir_emit_dots() always adds . & .. and sets the current dir pos to 2 (0 and 1 are done). Therefore we always want the index_to_find to be 2 regardless of if the response has . and .. B) smb1 code initializes index_of_last_entry with a +2 offset in cifssmb.c CIFSFindFirst(): psrch_inf->index_of_last_entry = 2 /* skip . and .. */ + psrch_inf->entries_in_buffer; Later in find_cifs_entry() we want to find the next dir entry at pos=2 as a result of (A) first_entry_in_buffer = cfile->srch_inf.index_of_last_entry - cfile->srch_inf.entries_in_buffer; This var is the dir pos that the first entry in the buffer will have therefore it must be 2 in the first call. If we don't offset index_of_last_entry by 2 (like in (B)), first_entry_in_buffer=0 but we were instructed to get pos=2 so this code in find_cifs_entry() skips the 2 first which is ok for non-root shares, as it skips . and .. from the response but is not ok for root shares where the 2 first are actual files pos_in_buf = index_to_find - first_entry_in_buffer; // pos_in_buf=2 // we skip 2 first response entries :( for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) { /* go entry by entry figuring out which is first */ cur_ent = nxt_dir_entry(cur_ent, end_of_smb, cfile->srch_inf.info_level); } C) cifs_filldir() skips . and .. so we can safely ignore them for now. Sample program: int main(int argc, char **argv) { const char *path = argc >= 2 ? argv[1] : "."; DIR *dh; struct dirent *de; printf("listing path <%s>\n", path); dh = opendir(path); if (!dh) { printf("opendir error %d\n", errno); return 1; } while (1) { de = readdir(dh); if (!de) { if (errno) { printf("readdir error %d\n", errno); return 1; } printf("end of listing\n"); break; } printf("off=%lu <%s>\n", de->d_off, de->d_name); } return 0; } Before the fix with SMB1 on root shares: <.> off=1 <..> off=2 <$Recycle.Bin> off=3 off=4 and on non-root shares: <.> off=1 <..> off=4 <-- after adding .., the offsets jumps to +2 because <2536> off=5 we skipped . and .. from response buffer (C) <411> off=6 but still incremented pos off=7 off=8 Therefore the fix for smb2 is to mimic smb1 behaviour and offset the index_of_last_entry by 2. Test results comparing smb1 and smb2 before/after the fix on root share, non-root shares and on large directories (ie. multi-response dir listing): PRE FIX ======= pre-1-root VS pre-2-root: ERR pre-2-root is missing [bootmgr, $Recycle.Bin] pre-1-nonroot VS pre-2-nonroot: OK~ same files, same order, different offsets pre-1-nonroot-large VS pre-2-nonroot-large: OK~ same files, same order, different offsets POST FIX ======== post-1-root VS post-2-root: OK same files, same order, same offsets post-1-nonroot VS post-2-nonroot: OK same files, same order, same offsets post-1-nonroot-large VS post-2-nonroot-large: OK same files, same order, same offsets REGRESSION? =========== pre-1-root VS post-1-root: OK same files, same order, same offsets pre-1-nonroot VS post-1-nonroot: OK same files, same order, same offsets BugLink: https://bugzilla.samba.org/show_bug.cgi?id=13107 Signed-off-by: Aurelien Aptel Signed-off-by: Paulo Alcantara --- fs/cifs/smb2ops.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index ceaa358723f0..95d3f1e080c4 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -1267,7 +1267,7 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon, } srch_inf->entries_in_buffer = 0; - srch_inf->index_of_last_entry = 0; + srch_inf->index_of_last_entry = 2; rc = SMB2_query_directory(xid, tcon, fid->persistent_fid, fid->volatile_fid, 0, srch_inf);