From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/fs/cifs/cifs_dfs_ref.c | 202 +++++++++++++++++++++++++++++---------------------
1 files changed, 116 insertions(+), 86 deletions(-)
diff --git a/kernel/fs/cifs/cifs_dfs_ref.c b/kernel/fs/cifs/cifs_dfs_ref.c
index 563e2f6..4212560 100644
--- a/kernel/fs/cifs/cifs_dfs_ref.c
+++ b/kernel/fs/cifs/cifs_dfs_ref.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Contains the CIFS DFS referral mounting routines used for handling
* traversal via DFS junction point
@@ -6,10 +7,6 @@
* Copyright (C) International Business Machines Corp., 2008
* Author(s): Igor Mammedov (niallain@gmail.com)
* Steve French (sfrench@us.ibm.com)
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
*/
#include <linux/dcache.h>
@@ -25,6 +22,7 @@
#include "dns_resolve.h"
#include "cifs_debug.h"
#include "cifs_unicode.h"
+#include "dfs_cache.h"
static LIST_HEAD(cifs_dfs_automount_list);
@@ -122,17 +120,17 @@
/**
- * cifs_compose_mount_options - creates mount options for refferral
+ * cifs_compose_mount_options - creates mount options for referral
* @sb_mountdata: parent/root DFS mount options (template)
* @fullpath: full path in UNC format
- * @ref: server's referral
- * @devname: pointer for saving device name
+ * @ref: optional server's referral
+ * @devname: optional pointer for saving device name
*
* creates mount options for submount based on template options sb_mountdata
* and replacing unc,ip,prefixpath options with ones we've got form ref_unc.
*
* Returns: pointer to new mount options or ERR_PTR.
- * Caller is responcible for freeing retunrned value if it is not error.
+ * Caller is responsible for freeing returned value if it is not error.
*/
char *cifs_compose_mount_options(const char *sb_mountdata,
const char *fullpath,
@@ -140,6 +138,7 @@
char **devname)
{
int rc;
+ char *name;
char *mountdata = NULL;
const char *prepath = NULL;
int md_len;
@@ -151,24 +150,36 @@
if (sb_mountdata == NULL)
return ERR_PTR(-EINVAL);
- if (strlen(fullpath) - ref->path_consumed) {
- prepath = fullpath + ref->path_consumed;
- /* skip initial delimiter */
- if (*prepath == '/' || *prepath == '\\')
- prepath++;
+ if (ref) {
+ if (WARN_ON_ONCE(!ref->node_name || ref->path_consumed < 0))
+ return ERR_PTR(-EINVAL);
+
+ if (strlen(fullpath) - ref->path_consumed) {
+ prepath = fullpath + ref->path_consumed;
+ /* skip initial delimiter */
+ if (*prepath == '/' || *prepath == '\\')
+ prepath++;
+ }
+
+ name = cifs_build_devname(ref->node_name, prepath);
+ if (IS_ERR(name)) {
+ rc = PTR_ERR(name);
+ name = NULL;
+ goto compose_mount_options_err;
+ }
+ } else {
+ name = cifs_build_devname((char *)fullpath, NULL);
+ if (IS_ERR(name)) {
+ rc = PTR_ERR(name);
+ name = NULL;
+ goto compose_mount_options_err;
+ }
}
- *devname = cifs_build_devname(ref->node_name, prepath);
- if (IS_ERR(*devname)) {
- rc = PTR_ERR(*devname);
- *devname = NULL;
- goto compose_mount_options_err;
- }
-
- rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
+ rc = dns_resolve_server_name_to_ip(name, &srvIP);
if (rc < 0) {
cifs_dbg(FYI, "%s: Failed to resolve server part of %s to IP: %d\n",
- __func__, *devname, rc);
+ __func__, name, rc);
goto compose_mount_options_err;
}
@@ -224,6 +235,11 @@
strcat(mountdata, "ip=");
strcat(mountdata, srvIP);
+ if (devname)
+ *devname = name;
+ else
+ kfree(name);
+
/*cifs_dbg(FYI, "%s: parent mountdata: %s\n", __func__, sb_mountdata);*/
/*cifs_dbg(FYI, "%s: submount mountdata: %s\n", __func__, mountdata );*/
@@ -234,47 +250,46 @@
compose_mount_options_err:
kfree(mountdata);
mountdata = ERR_PTR(rc);
- kfree(*devname);
- *devname = NULL;
+ kfree(name);
goto compose_mount_options_out;
}
/**
- * cifs_dfs_do_refmount - mounts specified path using provided refferal
+ * cifs_dfs_do_mount - mounts specified path using DFS full path
+ *
+ * Always pass down @fullpath to smb3_do_mount() so we can use the root server
+ * to perform failover in case we failed to connect to the first target in the
+ * referral.
+ *
* @cifs_sb: parent/root superblock
* @fullpath: full path in UNC format
- * @ref: server's referral
*/
-static struct vfsmount *cifs_dfs_do_refmount(struct dentry *mntpt,
- struct cifs_sb_info *cifs_sb,
- const char *fullpath, const struct dfs_info3_param *ref)
+static struct vfsmount *cifs_dfs_do_mount(struct dentry *mntpt,
+ struct cifs_sb_info *cifs_sb,
+ const char *fullpath)
{
struct vfsmount *mnt;
char *mountdata;
- char *devname = NULL;
+ char *devname;
+
+ devname = kstrndup(fullpath, strlen(fullpath), GFP_KERNEL);
+ if (!devname)
+ return ERR_PTR(-ENOMEM);
+
+ convert_delimiter(devname, '/');
/* strip first '\' from fullpath */
mountdata = cifs_compose_mount_options(cifs_sb->mountdata,
- fullpath + 1, ref, &devname);
-
- if (IS_ERR(mountdata))
+ fullpath + 1, NULL, NULL);
+ if (IS_ERR(mountdata)) {
+ kfree(devname);
return (struct vfsmount *)mountdata;
+ }
mnt = vfs_submount(mntpt, &cifs_fs_type, devname, mountdata);
kfree(mountdata);
kfree(devname);
return mnt;
-
-}
-
-static void dump_referral(const struct dfs_info3_param *ref)
-{
- cifs_dbg(FYI, "DFS: ref path: %s\n", ref->path_name);
- cifs_dbg(FYI, "DFS: node path: %s\n", ref->node_name);
- cifs_dbg(FYI, "DFS: fl: %d, srv_type: %d\n",
- ref->flags, ref->server_type);
- cifs_dbg(FYI, "DFS: ref_flags: %d, path_consumed: %d\n",
- ref->ref_flag, ref->path_consumed);
}
/*
@@ -282,16 +297,13 @@
*/
static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
{
- struct dfs_info3_param *referrals = NULL;
- unsigned int num_referrals = 0;
struct cifs_sb_info *cifs_sb;
struct cifs_ses *ses;
- char *full_path;
+ struct cifs_tcon *tcon;
+ char *full_path, *root_path;
unsigned int xid;
- int i;
int rc;
struct vfsmount *mnt;
- struct tcon_link *tlink;
cifs_dbg(FYI, "in %s\n", __func__);
BUG_ON(IS_ROOT(mntpt));
@@ -304,54 +316,72 @@
*/
mnt = ERR_PTR(-ENOMEM);
+ cifs_sb = CIFS_SB(mntpt->d_sb);
+ if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_DFS) {
+ mnt = ERR_PTR(-EREMOTE);
+ goto cdda_exit;
+ }
+
/* always use tree name prefix */
full_path = build_path_from_dentry_optional_prefix(mntpt, true);
if (full_path == NULL)
goto cdda_exit;
- cifs_sb = CIFS_SB(mntpt->d_sb);
- tlink = cifs_sb_tlink(cifs_sb);
- if (IS_ERR(tlink)) {
- mnt = ERR_CAST(tlink);
+ convert_delimiter(full_path, '\\');
+
+ cifs_dbg(FYI, "%s: full_path: %s\n", __func__, full_path);
+
+ if (!cifs_sb_master_tlink(cifs_sb)) {
+ cifs_dbg(FYI, "%s: master tlink is NULL\n", __func__);
goto free_full_path;
}
- ses = tlink_tcon(tlink)->ses;
- xid = get_xid();
- rc = get_dfs_path(xid, ses, full_path + 1, cifs_sb->local_nls,
- &num_referrals, &referrals,
- cifs_remap(cifs_sb));
- free_xid(xid);
-
- cifs_put_tlink(tlink);
-
- mnt = ERR_PTR(-ENOENT);
- for (i = 0; i < num_referrals; i++) {
- int len;
- dump_referral(referrals + i);
- /* connect to a node */
- len = strlen(referrals[i].node_name);
- if (len < 2) {
- cifs_dbg(VFS, "%s: Net Address path too short: %s\n",
- __func__, referrals[i].node_name);
- mnt = ERR_PTR(-EINVAL);
- break;
- }
- mnt = cifs_dfs_do_refmount(mntpt, cifs_sb,
- full_path, referrals + i);
- cifs_dbg(FYI, "%s: cifs_dfs_do_refmount:%s , mnt:%p\n",
- __func__, referrals[i].node_name, mnt);
- if (!IS_ERR(mnt))
- goto success;
+ tcon = cifs_sb_master_tcon(cifs_sb);
+ if (!tcon) {
+ cifs_dbg(FYI, "%s: master tcon is NULL\n", __func__);
+ goto free_full_path;
}
- /* no valid submounts were found; return error from get_dfs_path() by
- * preference */
- if (rc != 0)
- mnt = ERR_PTR(rc);
+ root_path = kstrdup(tcon->treeName, GFP_KERNEL);
+ if (!root_path) {
+ mnt = ERR_PTR(-ENOMEM);
+ goto free_full_path;
+ }
+ cifs_dbg(FYI, "%s: root path: %s\n", __func__, root_path);
-success:
- free_dfs_info_array(referrals, num_referrals);
+ ses = tcon->ses;
+ xid = get_xid();
+
+ /*
+ * If DFS root has been expired, then unconditionally fetch it again to
+ * refresh DFS referral cache.
+ */
+ rc = dfs_cache_find(xid, ses, cifs_sb->local_nls, cifs_remap(cifs_sb),
+ root_path + 1, NULL, NULL);
+ if (!rc) {
+ rc = dfs_cache_find(xid, ses, cifs_sb->local_nls,
+ cifs_remap(cifs_sb), full_path + 1,
+ NULL, NULL);
+ }
+
+ free_xid(xid);
+
+ if (rc) {
+ mnt = ERR_PTR(rc);
+ goto free_root_path;
+ }
+ /*
+ * OK - we were able to get and cache a referral for @full_path.
+ *
+ * Now, pass it down to cifs_mount() and it will retry every available
+ * node server in case of failures - no need to do it here.
+ */
+ mnt = cifs_dfs_do_mount(mntpt, cifs_sb, full_path);
+ cifs_dbg(FYI, "%s: cifs_dfs_do_mount:%s , mnt:%p\n", __func__,
+ full_path + 1, mnt);
+
+free_root_path:
+ kfree(root_path);
free_full_path:
kfree(full_path);
cdda_exit:
--
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