[linux.git] / fs / cifs / cifs_dfs_ref.c

/*
 *   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 ([email protected])
 *		Steve French ([email protected])
 *   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 <linux/vfs.h>
#include <linux/fs.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,
			    cifs_dfs_expire_automounts);
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;

	mark_mounts_for_expiry(list);
	if (!list_empty(list))
		schedule_delayed_work(&cifs_dfs_automount_task,
				      cifs_dfs_mountpoint_expiry_timeout);
}

void cifs_dfs_release_automount_timer(void)
{
	BUG_ON(!list_empty(&cifs_dfs_automount_list));
	cancel_delayed_work(&cifs_dfs_automount_task);
	flush_scheduled_work();
}

/**
 * cifs_get_share_name	-	extracts share name from UNC
 * @node_name:	pointer to UNC string
 *
 * Extracts sharename form full UNC.
 * i.e. strips from UNC trailing path that is not part of share
 * name and fixup missing '\' in the begining of DFS node refferal
 * if neccessary.
 * Returns pointer to share name on success or NULL on error.
 * Caller is responsible for freeing returned string.
 */
static char *cifs_get_share_name(const char *node_name)
{
	int len;
	char *UNC;
	char *pSep;

	len = strlen(node_name);
	UNC = kmalloc(len+2 /*for term null and additional \ if it's missed */,
			 GFP_KERNEL);
	if (!UNC)
		return NULL;

	/* get share name and server name */
	if (node_name[1] != '\\') {
		UNC[0] = '\\';
		strncpy(UNC+1, node_name, len);
		len++;
		UNC[len] = 0;
	} else {
		strncpy(UNC, node_name, len);
		UNC[len] = 0;
	}

	/* find server name end */
	pSep = memchr(UNC+2, '\\', len-2);
	if (!pSep) {
		cERROR(1, ("%s: no server name end in node name: %s",
			__func__, node_name));
		kfree(UNC);
		return NULL;
	}

	/* find sharename end */
	pSep++;
	pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC));
	if (pSep) {
		/* trim path up to sharename end
		 * now we have share name in UNC */
		*pSep = 0;
	}

	return UNC;
}


/**
 * compose_mount_options	-	creates mount options for refferral
 * @sb_mountdata:	parent/root DFS mount options (template)
 * @ref_unc:		refferral server UNC
 * @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.
 */
static char *compose_mount_options(const char *sb_mountdata,
				   const char *ref_unc,
				   char **devname)
{
	int rc;
	char *mountdata;
	int md_len;
	char *tkn_e;
	char *srvIP = NULL;
	char sep = ',';
	int off, noff;

	if (sb_mountdata == NULL)
		return ERR_PTR(-EINVAL);

	*devname = cifs_get_share_name(ref_unc);
	rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
	if (rc != 0) {
		cERROR(1, ("%s: Failed to resolve server part of %s to IP",
			  __func__, *devname));
		mountdata = ERR_PTR(rc);
		goto compose_mount_options_out;
	}
	md_len = strlen(sb_mountdata) + strlen(srvIP) + strlen(ref_unc) + 3;
	mountdata = kzalloc(md_len+1, GFP_KERNEL);
	if (mountdata == NULL) {
		mountdata = ERR_PTR(-ENOMEM);
		goto compose_mount_options_out;
	}

	/* 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;
	}
	while ((tkn_e = strchr(sb_mountdata+off, sep))) {
		noff = (tkn_e - (sb_mountdata+off)) + 1;
		if (strnicmp(sb_mountdata+off, "unc=", 4) == 0) {
			off += noff;
			continue;
		}
		if (strnicmp(sb_mountdata+off, "ip=", 3) == 0) {
			off += noff;
			continue;
		}
		if (strnicmp(sb_mountdata+off, "prefixpath=", 3) == 0) {
			off += noff;
			continue;
		}
		strncat(mountdata, sb_mountdata+off, noff);
		off += noff;
	}
	strcat(mountdata, sb_mountdata+off);
	mountdata[md_len] = '\0';

	/* copy new IP and ref share name */
	strcat(mountdata, ",ip=");
	strcat(mountdata, srvIP);
	strcat(mountdata, ",unc=");
	strcat(mountdata, *devname);

	/* find & copy prefixpath */
	tkn_e = strchr(ref_unc+2, '\\');
	if (tkn_e) {
		tkn_e = strchr(tkn_e+1, '\\');
		if (tkn_e) {
			strcat(mountdata, ",prefixpath=");
			strcat(mountdata, tkn_e+1);
		}
	}

	/*cFYI(1,("%s: parent mountdata: %s", __func__,sb_mountdata));*/
	/*cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));*/

compose_mount_options_out:
	kfree(srvIP);
	return mountdata;
}


static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent,
		struct dentry *dentry, char *ref_unc)
{
	struct cifs_sb_info *cifs_sb;
	struct vfsmount *mnt;
	char *mountdata;
	char *devname = NULL;

	cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
	mountdata = compose_mount_options(cifs_sb->mountdata,
						ref_unc, &devname);

	if (IS_ERR(mountdata))
		return (struct vfsmount *)mountdata;

	mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata);
	kfree(mountdata);
	kfree(devname);
	return mnt;

}

static char *build_full_dfs_path_from_dentry(struct dentry *dentry)
{
	char *full_path = NULL;
	char *search_path;
	char *tmp_path;
	size_t l_max_len;
	struct cifs_sb_info *cifs_sb;

	if (dentry->d_inode == NULL)
		return NULL;

	cifs_sb = CIFS_SB(dentry->d_inode->i_sb);

	if (cifs_sb->tcon == NULL)
		return NULL;

	search_path = build_path_from_dentry(dentry);
	if (search_path == NULL)
		return NULL;

	if (cifs_sb->tcon->Flags & SMB_SHARE_IS_IN_DFS) {
		int i;
		/* we should use full path name for correct working with DFS */
		l_max_len = strnlen(cifs_sb->tcon->treeName, MAX_TREE_SIZE+1) +
					strnlen(search_path, MAX_PATHCONF) + 1;
		tmp_path = kmalloc(l_max_len, GFP_KERNEL);
		if (tmp_path == NULL) {
			kfree(search_path);
			return NULL;
		}
		strncpy(tmp_path, cifs_sb->tcon->treeName, l_max_len);
		tmp_path[l_max_len-1] = 0;
		if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)
			for (i = 0; i < l_max_len; i++) {
				if (tmp_path[i] == '\\')
					tmp_path[i] = '/';
			}
		strncat(tmp_path, search_path, l_max_len - strlen(tmp_path));

		full_path = tmp_path;
		kfree(search_path);
	} else {
		full_path = search_path;
	}
	return full_path;
}

static int add_mount_helper(struct vfsmount *newmnt, struct nameidata *nd,
				struct list_head *mntlist)
{
	/* stolen from afs code */
	int err;

	mntget(newmnt);
	err = do_add_mount(newmnt, nd, nd->path.mnt->mnt_flags, mntlist);
	switch (err) {
	case 0:
		path_put(&nd->path);
		nd->path.mnt = newmnt;
		nd->path.dentry = dget(newmnt->mnt_root);
		schedule_delayed_work(&cifs_dfs_automount_task,
				      cifs_dfs_mountpoint_expiry_timeout);
		break;
	case -EBUSY:
		/* someone else made a mount here whilst we were busy */
		while (d_mountpoint(nd->path.dentry) &&
		       follow_down(&nd->path.mnt, &nd->path.dentry))
			;
		err = 0;
	default:
		mntput(newmnt);
		break;
	}
	return err;
}

static void dump_referral(const struct dfs_info3_param *ref)
{
	cFYI(1, ("DFS: ref path: %s", ref->path_name));
	cFYI(1, ("DFS: node path: %s", ref->node_name));
	cFYI(1, ("DFS: fl: %hd, srv_type: %hd", ref->flags, ref->server_type));
	cFYI(1, ("DFS: ref_flags: %hd, path_consumed: %hd", ref->ref_flag,
				ref->path_consumed));
}


static void*
cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
{
	struct dfs_info3_param *referrals = NULL;
	unsigned int num_referrals = 0;
	struct cifs_sb_info *cifs_sb;
	struct cifsSesInfo *ses;
	char *full_path = NULL;
	int xid, i;
	int rc = 0;
	struct vfsmount *mnt = ERR_PTR(-ENOENT);

	cFYI(1, ("in %s", __func__));
	BUG_ON(IS_ROOT(dentry));

	xid = GetXid();

	dput(nd->path.dentry);
	nd->path.dentry = dget(dentry);

	cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
	ses = cifs_sb->tcon->ses;

	if (!ses) {
		rc = -EINVAL;
		goto out_err;
	}

	full_path = build_full_dfs_path_from_dentry(dentry);
	if (full_path == NULL) {
		rc = -ENOMEM;
		goto out_err;
	}

	rc = get_dfs_path(xid, ses , full_path, cifs_sb->local_nls,
		&num_referrals, &referrals,
		cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);

	for (i = 0; i < num_referrals; i++) {
		dump_referral(referrals+i);
		/* connect to a storage node */
		if (referrals[i].flags & DFSREF_STORAGE_SERVER) {
			int len;
			len = strlen(referrals[i].node_name);
			if (len < 2) {
				cERROR(1, ("%s: Net Address path too short: %s",
					__func__, referrals[i].node_name));
				rc = -EINVAL;
				goto out_err;
			}
			mnt = cifs_dfs_do_refmount(nd->path.mnt,
						nd->path.dentry,
						referrals[i].node_name);
			cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p",
					 __func__,
					referrals[i].node_name, mnt));

			/* complete mount procedure if we accured submount */
			if (!IS_ERR(mnt))
				break;
		}
	}

	/* we need it cause for() above could exit without valid submount */
	rc = PTR_ERR(mnt);
	if (IS_ERR(mnt))
		goto out_err;

	nd->path.mnt->mnt_flags |= MNT_SHRINKABLE;
	rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);

out:
	FreeXid(xid);
	free_dfs_info_array(referrals, num_referrals);
	kfree(full_path);
	cFYI(1, ("leaving %s" , __func__));
	return ERR_PTR(rc);
out_err:
	path_put(&nd->path);
	goto out;
}

struct inode_operations cifs_dfs_referral_inode_operations = {
	.follow_link = cifs_dfs_follow_mountpoint,
};
Commit	Line	Data
6d5ae0de IM	1	/*
	2	* Contains the CIFS DFS referral mounting routines used for handling
	3	* traversal via DFS junction point
	4	*
	5	* Copyright (c) 2007 Igor Mammedov
366781c1	6	* Copyright (C) International Business Machines Corp., 2008
6d5ae0de	7	* Author(s): Igor Mammedov ([email protected])
366781c1	8	* Steve French ([email protected])
6d5ae0de IM	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License
	11	* as published by the Free Software Foundation; either version
	12	* 2 of the License, or (at your option) any later version.
	13	*/
	14
	15	#include <linux/dcache.h>
	16	#include <linux/mount.h>
	17	#include <linux/namei.h>
	18	#include <linux/vfs.h>
	19	#include <linux/fs.h>
	20	#include "cifsglob.h"
	21	#include "cifsproto.h"
	22	#include "cifsfs.h"
	23	#include "dns_resolve.h"
	24	#include "cifs_debug.h"
	25
8d142137	26	static LIST_HEAD(cifs_dfs_automount_list);
6d5ae0de	27
78d31a3a IM	28	static void cifs_dfs_expire_automounts(struct work_struct *work);
	29	static DECLARE_DELAYED_WORK(cifs_dfs_automount_task,
	30	cifs_dfs_expire_automounts);
	31	static int cifs_dfs_mountpoint_expiry_timeout = 500 * HZ;
	32
	33	static void cifs_dfs_expire_automounts(struct work_struct *work)
	34	{
	35	struct list_head *list = &cifs_dfs_automount_list;
	36
	37	mark_mounts_for_expiry(list);
	38	if (!list_empty(list))
	39	schedule_delayed_work(&cifs_dfs_automount_task,
	40	cifs_dfs_mountpoint_expiry_timeout);
	41	}
6d5ae0de	42
78d31a3a	43	void cifs_dfs_release_automount_timer(void)
6d5ae0de	44	{
78d31a3a IM	45	BUG_ON(!list_empty(&cifs_dfs_automount_list));
	46	cancel_delayed_work(&cifs_dfs_automount_task);
	47	flush_scheduled_work();
6d5ae0de IM	48	}
	49
	50	/**
	51	* cifs_get_share_name - extracts share name from UNC
	52	* @node_name: pointer to UNC string
	53	*
	54	* Extracts sharename form full UNC.
	55	* i.e. strips from UNC trailing path that is not part of share
	56	* name and fixup missing '\' in the begining of DFS node refferal
	57	* if neccessary.
	58	* Returns pointer to share name on success or NULL on error.
	59	* Caller is responsible for freeing returned string.
	60	*/
	61	static char cifs_get_share_name(const char node_name)
	62	{
	63	int len;
	64	char *UNC;
	65	char *pSep;
	66
	67	len = strlen(node_name);
	68	UNC = kmalloc(len+2 /for term null and additional \ if it's missed /,
	69	GFP_KERNEL);
	70	if (!UNC)
	71	return NULL;
	72
	73	/* get share name and server name */
	74	if (node_name[1] != '\\') {
	75	UNC[0] = '\\';
	76	strncpy(UNC+1, node_name, len);
	77	len++;
	78	UNC[len] = 0;
	79	} else {
	80	strncpy(UNC, node_name, len);
	81	UNC[len] = 0;
	82	}
	83
	84	/* find server name end */
	85	pSep = memchr(UNC+2, '\\', len-2);
	86	if (!pSep) {
	87	cERROR(1, ("%s: no server name end in node name: %s",
55f78e17	88	__func__, node_name));
6d5ae0de IM	89	kfree(UNC);
	90	return NULL;
	91	}
	92
	93	/* find sharename end */
	94	pSep++;
	95	pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC));
bf62fd88 IM	96	if (pSep) {
	97	/* trim path up to sharename end
	98	* now we have share name in UNC */
	99	*pSep = 0;
6d5ae0de	100	}
6d5ae0de IM	101
	102	return UNC;
	103	}
	104
	105
	106	/**
	107	* compose_mount_options - creates mount options for refferral
	108	* @sb_mountdata: parent/root DFS mount options (template)
	109	* @ref_unc: refferral server UNC
	110	* @devname: pointer for saving device name
	111	*
	112	* creates mount options for submount based on template options sb_mountdata
	113	* and replacing unc,ip,prefixpath options with ones we've got form ref_unc.
	114	*
	115	* Returns: pointer to new mount options or ERR_PTR.
	116	* Caller is responcible for freeing retunrned value if it is not error.
	117	*/
366781c1 SF	118	static char compose_mount_options(const char sb_mountdata,
	119	const char *ref_unc,
	120	char **devname)
6d5ae0de IM	121	{
	122	int rc;
	123	char *mountdata;
	124	int md_len;
	125	char *tkn_e;
	126	char *srvIP = NULL;
	127	char sep = ',';
	128	int off, noff;
	129
	130	if (sb_mountdata == NULL)
	131	return ERR_PTR(-EINVAL);
	132
	133	*devname = cifs_get_share_name(ref_unc);
	134	rc = dns_resolve_server_name_to_ip(*devname, &srvIP);
	135	if (rc != 0) {
	136	cERROR(1, ("%s: Failed to resolve server part of %s to IP",
55f78e17	137	__func__, *devname));
6d5ae0de IM	138	mountdata = ERR_PTR(rc);
	139	goto compose_mount_options_out;
	140	}
	141	md_len = strlen(sb_mountdata) + strlen(srvIP) + strlen(ref_unc) + 3;
	142	mountdata = kzalloc(md_len+1, GFP_KERNEL);
	143	if (mountdata == NULL) {
	144	mountdata = ERR_PTR(-ENOMEM);
	145	goto compose_mount_options_out;
	146	}
	147
	148	/* copy all options except of unc,ip,prefixpath */
	149	off = 0;
	150	if (strncmp(sb_mountdata, "sep=", 4) == 0) {
	151	sep = sb_mountdata[4];
	152	strncpy(mountdata, sb_mountdata, 5);
	153	off += 5;
	154	}
	155	while ((tkn_e = strchr(sb_mountdata+off, sep))) {
	156	noff = (tkn_e - (sb_mountdata+off)) + 1;
	157	if (strnicmp(sb_mountdata+off, "unc=", 4) == 0) {
	158	off += noff;
	159	continue;
	160	}
	161	if (strnicmp(sb_mountdata+off, "ip=", 3) == 0) {
	162	off += noff;
	163	continue;
	164	}
	165	if (strnicmp(sb_mountdata+off, "prefixpath=", 3) == 0) {
	166	off += noff;
	167	continue;
	168	}
	169	strncat(mountdata, sb_mountdata+off, noff);
	170	off += noff;
	171	}
	172	strcat(mountdata, sb_mountdata+off);
	173	mountdata[md_len] = '\0';
	174
	175	/* copy new IP and ref share name */
	176	strcat(mountdata, ",ip=");
	177	strcat(mountdata, srvIP);
	178	strcat(mountdata, ",unc=");
	179	strcat(mountdata, *devname);
	180
	181	/* find & copy prefixpath */
	182	tkn_e = strchr(ref_unc+2, '\\');
	183	if (tkn_e) {
	184	tkn_e = strchr(tkn_e+1, '\\');
	185	if (tkn_e) {
	186	strcat(mountdata, ",prefixpath=");
bf62fd88	187	strcat(mountdata, tkn_e+1);
6d5ae0de IM	188	}
	189	}
	190
55f78e17 HH	191	/cFYI(1,("%s: parent mountdata: %s", __func__,sb_mountdata));/
55f78e17 HH	192	/cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));/
6d5ae0de IM	193
	194	compose_mount_options_out:
	195	kfree(srvIP);
	196	return mountdata;
	197	}
	198
	199
366781c1	200	static struct vfsmount cifs_dfs_do_refmount(const struct vfsmount mnt_parent,
6d5ae0de IM	201	struct dentry dentry, char ref_unc)
	202	{
	203	struct cifs_sb_info *cifs_sb;
	204	struct vfsmount *mnt;
	205	char *mountdata;
366781c1	206	char *devname = NULL;
6d5ae0de IM	207
	208	cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
	209	mountdata = compose_mount_options(cifs_sb->mountdata,
	210	ref_unc, &devname);
	211
	212	if (IS_ERR(mountdata))
	213	return (struct vfsmount *)mountdata;
	214
	215	mnt = vfs_kern_mount(&cifs_fs_type, 0, devname, mountdata);
	216	kfree(mountdata);
	217	kfree(devname);
	218	return mnt;
	219
	220	}
	221
	222	static char build_full_dfs_path_from_dentry(struct dentry dentry)
	223	{
	224	char *full_path = NULL;
	225	char *search_path;
	226	char *tmp_path;
	227	size_t l_max_len;
	228	struct cifs_sb_info *cifs_sb;
	229
	230	if (dentry->d_inode == NULL)
	231	return NULL;
	232
	233	cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
	234
	235	if (cifs_sb->tcon == NULL)
	236	return NULL;
	237
	238	search_path = build_path_from_dentry(dentry);
	239	if (search_path == NULL)
	240	return NULL;
	241
	242	if (cifs_sb->tcon->Flags & SMB_SHARE_IS_IN_DFS) {
bf62fd88 IM	243	int i;
bf62fd88 IM	244	/* we should use full path name for correct working with DFS */
6d5ae0de IM	245	l_max_len = strnlen(cifs_sb->tcon->treeName, MAX_TREE_SIZE+1) +
	246	strnlen(search_path, MAX_PATHCONF) + 1;
	247	tmp_path = kmalloc(l_max_len, GFP_KERNEL);
	248	if (tmp_path == NULL) {
	249	kfree(search_path);
	250	return NULL;
	251	}
	252	strncpy(tmp_path, cifs_sb->tcon->treeName, l_max_len);
6d5ae0de	253	tmp_path[l_max_len-1] = 0;
bf62fd88 IM	254	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)
	255	for (i = 0; i < l_max_len; i++) {
	256	if (tmp_path[i] == '\\')
	257	tmp_path[i] = '/';
	258	}
	259	strncat(tmp_path, search_path, l_max_len - strlen(tmp_path));
	260
6d5ae0de IM	261	full_path = tmp_path;
	262	kfree(search_path);
	263	} else {
	264	full_path = search_path;
	265	}
	266	return full_path;
	267	}
	268
	269	static int add_mount_helper(struct vfsmount newmnt, struct nameidata nd,
	270	struct list_head *mntlist)
	271	{
	272	/* stolen from afs code */
	273	int err;
	274
	275	mntget(newmnt);
4ac91378	276	err = do_add_mount(newmnt, nd, nd->path.mnt->mnt_flags, mntlist);
6d5ae0de IM	277	switch (err) {
6d5ae0de IM	278	case 0:
78d31a3a	279	path_put(&nd->path);
4ac91378 JB	280	nd->path.mnt = newmnt;
4ac91378 JB	281	nd->path.dentry = dget(newmnt->mnt_root);
78d31a3a IM	282	schedule_delayed_work(&cifs_dfs_automount_task,
78d31a3a IM	283	cifs_dfs_mountpoint_expiry_timeout);
6d5ae0de IM	284	break;
	285	case -EBUSY:
	286	/* someone else made a mount here whilst we were busy */
4ac91378 JB	287	while (d_mountpoint(nd->path.dentry) &&
4ac91378 JB	288	follow_down(&nd->path.mnt, &nd->path.dentry))
6d5ae0de IM	289	;
	290	err = 0;
	291	default:
	292	mntput(newmnt);
	293	break;
	294	}
	295	return err;
	296	}
	297
366781c1	298	static void dump_referral(const struct dfs_info3_param *ref)
6d5ae0de IM	299	{
	300	cFYI(1, ("DFS: ref path: %s", ref->path_name));
	301	cFYI(1, ("DFS: node path: %s", ref->node_name));
	302	cFYI(1, ("DFS: fl: %hd, srv_type: %hd", ref->flags, ref->server_type));
	303	cFYI(1, ("DFS: ref_flags: %hd, path_consumed: %hd", ref->ref_flag,
8aad018b	304	ref->path_consumed));
6d5ae0de IM	305	}
	306
	307
	308	static void*
	309	cifs_dfs_follow_mountpoint(struct dentry dentry, struct nameidata nd)
	310	{
	311	struct dfs_info3_param *referrals = NULL;
	312	unsigned int num_referrals = 0;
	313	struct cifs_sb_info *cifs_sb;
	314	struct cifsSesInfo *ses;
	315	char *full_path = NULL;
	316	int xid, i;
	317	int rc = 0;
	318	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	319
55f78e17	320	cFYI(1, ("in %s", __func__));
6d5ae0de IM	321	BUG_ON(IS_ROOT(dentry));
	322
	323	xid = GetXid();
	324
4ac91378 JB	325	dput(nd->path.dentry);
4ac91378 JB	326	nd->path.dentry = dget(dentry);
6d5ae0de IM	327
	328	cifs_sb = CIFS_SB(dentry->d_inode->i_sb);
	329	ses = cifs_sb->tcon->ses;
	330
	331	if (!ses) {
	332	rc = -EINVAL;
	333	goto out_err;
	334	}
	335
	336	full_path = build_full_dfs_path_from_dentry(dentry);
	337	if (full_path == NULL) {
	338	rc = -ENOMEM;
	339	goto out_err;
	340	}
	341
	342	rc = get_dfs_path(xid, ses , full_path, cifs_sb->local_nls,
	343	&num_referrals, &referrals,
	344	cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
	345
	346	for (i = 0; i < num_referrals; i++) {
	347	dump_referral(referrals+i);
	348	/* connect to a storage node */
	349	if (referrals[i].flags & DFSREF_STORAGE_SERVER) {
	350	int len;
	351	len = strlen(referrals[i].node_name);
	352	if (len < 2) {
	353	cERROR(1, ("%s: Net Address path too short: %s",
55f78e17	354	__func__, referrals[i].node_name));
6d5ae0de IM	355	rc = -EINVAL;
	356	goto out_err;
	357	}
4ac91378 JB	358	mnt = cifs_dfs_do_refmount(nd->path.mnt,
4ac91378 JB	359	nd->path.dentry,
6d5ae0de IM	360	referrals[i].node_name);
6d5ae0de IM	361	cFYI(1, ("%s: cifs_dfs_do_refmount:%s , mnt:%p",
55f78e17	362	__func__,
6d5ae0de IM	363	referrals[i].node_name, mnt));
	364
	365	/* complete mount procedure if we accured submount */
	366	if (!IS_ERR(mnt))
	367	break;
	368	}
	369	}
	370
	371	/* we need it cause for() above could exit without valid submount */
	372	rc = PTR_ERR(mnt);
	373	if (IS_ERR(mnt))
	374	goto out_err;
	375
4ac91378	376	nd->path.mnt->mnt_flags \|= MNT_SHRINKABLE;
6d5ae0de IM	377	rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
	378
	379	out:
	380	FreeXid(xid);
	381	free_dfs_info_array(referrals, num_referrals);
	382	kfree(full_path);
55f78e17	383	cFYI(1, ("leaving %s" , __func__));
6d5ae0de IM	384	return ERR_PTR(rc);
6d5ae0de IM	385	out_err:
1d957f9b	386	path_put(&nd->path);
6d5ae0de IM	387	goto out;
	388	}
	389
	390	struct inode_operations cifs_dfs_referral_inode_operations = {
	391	.follow_link = cifs_dfs_follow_mountpoint,
	392	};
	393