original development tree for Linux kernel GTP module; now long in mainline.
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* Contains the CIFS DFS referral mounting routines used for handling
* traversal via DFS junction point
* Copyright (c) 2007 Igor Mammedov
* 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>
#include <linux/mount.h>
#include <linux/namei.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -&gt; slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It&#39;s put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn&#39;t seem to be any matching order. * If the script can&#39;t find a place to put a new include (mostly because the file doesn&#39;t have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn&#39;t need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn&#39;t work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I&#39;m fairly confident about the coverage of this conversion patch. If there is a breakage, it&#39;s likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo &lt;tj@kernel.org&gt; Guess-its-ok-by: Christoph Lameter &lt;cl@linux-foundation.org&gt; Cc: Ingo Molnar &lt;mingo@redhat.com&gt; Cc: Lee Schermerhorn &lt;Lee.Schermerhorn@hp.com&gt;
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#include <linux/slab.h>
#include <linux/vfs.h>
#include <linux/fs.h>
#include <linux/inet.h>
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifsfs.h"
#include "dns_resolve.h"
#include "cifs_debug.h"
static LIST_HEAD(cifs_dfs_automount_list);
static void cifs_dfs_expire_automounts(struct work_struct *work);
static DECLARE_DELAYED_WORK(cifs_dfs_automount_task,
static int cifs_dfs_mountpoint_expiry_timeout = 500 * HZ;
static void cifs_dfs_expire_automounts(struct work_struct *work)
struct list_head *list = &cifs_dfs_automount_list;
if (!list_empty(list))
void cifs_dfs_release_automount_timer(void)
* cifs_build_devname - build a devicename from a UNC and optional prepath
* @nodename: pointer to UNC string
* @prepath: pointer to prefixpath (or NULL if there isn't one)
* Build a new cifs devicename after chasing a DFS referral. Allocate a buffer
* big enough to hold the final thing. Copy the UNC from the nodename, and
* concatenate the prepath onto the end of it if there is one.
* Returns pointer to the built string, or a ERR_PTR. Caller is responsible
* for freeing the returned string.
static char *
cifs_build_devname(char *nodename, const char *prepath)
size_t pplen;
size_t unclen;
char *dev;
char *pos;
/* skip over any preceding delimiters */
nodename += strspn(nodename, "\\");
if (!*nodename)
return ERR_PTR(-EINVAL);
/* get length of UNC and set pos to last char */
unclen = strlen(nodename);
pos = nodename + unclen - 1;
/* trim off any trailing delimiters */
while (*pos == '\\') {
/* allocate a buffer:
* +2 for preceding "//"
* +1 for delimiter between UNC and prepath
* +1 for trailing NULL
pplen = prepath ? strlen(prepath) : 0;
dev = kmalloc(2 + unclen + 1 + pplen + 1, GFP_KERNEL);
if (!dev)
return ERR_PTR(-ENOMEM);
pos = dev;
/* add the initial "//" */
*pos = '/';
*pos = '/';
/* copy in the UNC portion from referral */
memcpy(pos, nodename, unclen);
pos += unclen;
/* copy the prefixpath remainder (if there is one) */
if (pplen) {
*pos = '/';
memcpy(pos, prepath, pplen);
pos += pplen;
/* NULL terminator */
*pos = '\0';
convert_delimiter(dev, '/');
return dev;
* cifs_compose_mount_options - creates mount options for refferral
* @sb_mountdata: parent/root DFS mount options (template)
* @fullpath: full path in UNC format
* @ref: server's referral
* @devname: 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.
char *cifs_compose_mount_options(const char *sb_mountdata,
const char *fullpath,
const struct dfs_info3_param *ref,
char **devname)
int rc;
char *mountdata = NULL;
const char *prepath = NULL;
int md_len;
char *tkn_e;
char *srvIP = NULL;
char sep = ',';
int off, noff;
if (sb_mountdata == NULL)
return ERR_PTR(-EINVAL);
if (strlen(fullpath) - ref->path_consumed)
prepath = fullpath + ref->path_consumed;
*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);
if (rc < 0) {
cifs_dbg(FYI, "%s: Failed to resolve server part of %s to IP: %d\n",
__func__, *devname, rc);
goto compose_mount_options_err;
* In most cases, we'll be building a shorter string than the original,
* but we do have to assume that the address in the ip= option may be
* much longer than the original. Add the max length of an address
* string to the length of the original string to allow for worst case.
md_len = strlen(sb_mountdata) + INET6_ADDRSTRLEN;
mountdata = kzalloc(md_len + 1, GFP_KERNEL);
if (mountdata == NULL) {
rc = -ENOMEM;
goto compose_mount_options_err;
/* copy all options except of unc,ip,prefixpath */
off = 0;
if (strncmp(sb_mountdata, "sep=", 4) == 0) {
sep = sb_mountdata[4];
strncpy(mountdata, sb_mountdata, 5);
off += 5;
do {
tkn_e = strchr(sb_mountdata + off, sep);
if (tkn_e == NULL)
noff = strlen(sb_mountdata + off);
noff = tkn_e - (sb_mountdata + off) + 1;
if (strnicmp(sb_mountdata + off, "unc=", 4) == 0) {
off += noff;
if (strnicmp(sb_mountdata + off, "ip=", 3) == 0) {
off += noff;
if (strnicmp(sb_mountdata + off, "prefixpath=", 11) == 0) {
off += noff;
strncat(mountdata, sb_mountdata + off, noff);
off += noff;
} while (tkn_e);
strcat(mountdata, sb_mountdata + off);
mountdata[md_len] = '\0';
/* copy new IP and ref share name */
if (mountdata[strlen(mountdata) - 1] != sep)
strncat(mountdata, &sep, 1);
strcat(mountdata, "ip=");
strcat(mountdata, srvIP);
/*cifs_dbg(FYI, "%s: parent mountdata: %s\n", __func__, sb_mountdata);*/
/*cifs_dbg(FYI, "%s: submount mountdata: %s\n", __func__, mountdata );*/
return mountdata;
mountdata = ERR_PTR(rc);
*devname = NULL;
goto compose_mount_options_out;
* cifs_dfs_do_refmount - mounts specified path using provided refferal
* @cifs_sb: parent/root superblock
* @fullpath: full path in UNC format
* @ref: server's referral
static struct vfsmount *cifs_dfs_do_refmount(struct cifs_sb_info *cifs_sb,
const char *fullpath, const struct dfs_info3_param *ref)
struct vfsmount *mnt;
char *mountdata;
char *devname = NULL;
/* strip first '\' from fullpath */
mountdata = cifs_compose_mount_options(cifs_sb->mountdata,
fullpath + 1, ref, &devname);
if (IS_ERR(mountdata))
return (struct vfsmount *)mountdata;
mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata);
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: %hd, srv_type: %hd\n",
ref->flags, ref->server_type);
cifs_dbg(FYI, "DFS: ref_flags: %hd, path_consumed: %hd\n",
ref->ref_flag, ref->path_consumed);
* Create a vfsmount that we can automount
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;
unsigned int xid;
int i;
int rc;
struct vfsmount *mnt;
struct tcon_link *tlink;
cifs_dbg(FYI, "in %s\n", __func__);
* The MSDFS spec states that paths in DFS referral requests and
* responses must be prefixed by a single '\' character instead of
* the double backslashes usually used in the UNC. This function
* gives us the latter, so we must adjust the result.
full_path = build_path_from_dentry(mntpt);
if (full_path == NULL)
11 years ago
goto cdda_exit;
cifs_sb = CIFS_SB(mntpt->d_inode->i_sb);
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink)) {
mnt = ERR_CAST(tlink);
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_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
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 = cifs_dfs_do_refmount(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;
/* no valid submounts were found; return error from get_dfs_path() by
* preference */
if (rc != 0)
mnt = ERR_PTR(rc);
free_dfs_info_array(referrals, num_referrals);
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cifs_dbg(FYI, "leaving %s\n" , __func__);
return mnt;
* Attempt to automount the referral
struct vfsmount *cifs_dfs_d_automount(struct path *path)
struct vfsmount *newmnt;
cifs_dbg(FYI, "in %s\n", __func__);
newmnt = cifs_dfs_do_automount(path->dentry);
if (IS_ERR(newmnt)) {
cifs_dbg(FYI, "leaving %s [automount failed]\n" , __func__);
return newmnt;
mntget(newmnt); /* prevent immediate expiration */
mnt_set_expiry(newmnt, &cifs_dfs_automount_list);
cifs_dbg(FYI, "leaving %s [ok]\n" , __func__);
return newmnt;
const struct inode_operations cifs_dfs_referral_inode_operations = {