1 files changed, 242 insertions, 241 deletions

diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index 56c924033b7..58df174deb1 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -15,90 +15,116 @@
 #include <linux/dcache.h>
 #include <linux/mount.h>
 #include <linux/namei.h>
+#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"
 
-LIST_HEAD(cifs_dfs_automount_list);
+static LIST_HEAD(cifs_dfs_automount_list);
 
-/*
- * DFS functions
-*/
+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 dfs_shrink_umount_helper(struct vfsmount *vfsmnt)
+void cifs_dfs_release_automount_timer(void)
 {
-	mark_mounts_for_expiry(&cifs_dfs_automount_list);
-	mark_mounts_for_expiry(&cifs_dfs_automount_list);
+	BUG_ON(!list_empty(&cifs_dfs_automount_list));
+	cancel_delayed_work_sync(&cifs_dfs_automount_task);
 }
 
 /**
- * cifs_get_share_name	-	extracts share name from UNC
- * @node_name:	pointer to UNC string
+ * 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)
  *
- * 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.
+ * 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_get_share_name(const char *node_name)
+static char *
+cifs_build_devname(char *nodename, const char *prepath)
 {
-	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;
-	}
+	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;
 
-	/* 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;
+	/* trim off any trailing delimiters */
+	while (*pos == '\\') {
+		--pos;
+		--unclen;
 	}
 
-	/* find sharename end */
-	pSep++;
-	pSep = memchr(UNC+(pSep-UNC), '\\', len-(pSep-UNC));
-	if (!pSep) {
-		cERROR(1, ("%s:2 cant find share name in node name: %s",
-			__func__, node_name));
-		kfree(UNC);
-		return NULL;
+	/* 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;
+	*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 = '/';
+		++pos;
+		memcpy(pos, prepath, pplen);
+		pos += pplen;
 	}
-	/* trim path up to sharename end
-	 *          * now we have share name in UNC */
-	*pSep = 0;
 
-	return UNC;
+	/* NULL terminator */
+	*pos = '\0';
+
+	convert_delimiter(dev, '/');
+	return dev;
 }
 
 
 /**
- * compose_mount_options	-	creates mount options for refferral
+ * cifs_compose_mount_options	-	creates mount options for refferral
  * @sb_mountdata:	parent/root DFS mount options (template)
- * @ref_unc:		refferral server UNC
+ * @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
@@ -107,12 +133,14 @@ static char *cifs_get_share_name(const char *node_name)
  * 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 *cifs_compose_mount_options(const char *sb_mountdata,
+				   const char *fullpath,
+				   const struct dfs_info3_param *ref,
 				   char **devname)
 {
 	int rc;
-	char *mountdata;
+	char *mountdata = NULL;
+	const char *prepath = NULL;
 	int md_len;
 	char *tkn_e;
 	char *srvIP = NULL;
@@ -122,19 +150,34 @@ static char *compose_mount_options(const char *sb_mountdata,
 	if (sb_mountdata == NULL)
 		return ERR_PTR(-EINVAL);
 
-	*devname = cifs_get_share_name(ref_unc);
+	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) {
-		cERROR(1, ("%s: Failed to resolve server part of %s to IP",
-			  __func__, *devname));
-		mountdata = ERR_PTR(rc);
-		goto compose_mount_options_out;
+	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;
 	}
-	md_len = strlen(sb_mountdata) + strlen(srvIP) + strlen(ref_unc) + 3;
-	mountdata = kzalloc(md_len+1, GFP_KERNEL);
+
+	/*
+	 * 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) {
-		mountdata = ERR_PTR(-ENOMEM);
-		goto compose_mount_options_out;
+		rc = -ENOMEM;
+		goto compose_mount_options_err;
 	}
 
 	/* copy all options except of unc,ip,prefixpath */
@@ -144,62 +187,69 @@ static char *compose_mount_options(const char *sb_mountdata,
 			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) {
+
+	do {
+		tkn_e = strchr(sb_mountdata + off, sep);
+		if (tkn_e == NULL)
+			noff = strlen(sb_mountdata + off);
+		else
+			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) {
+		if (strnicmp(sb_mountdata + off, "ip=", 3) == 0) {
 			off += noff;
 			continue;
 		}
-		if (strnicmp(sb_mountdata+off, "prefixpath=", 3) == 0) {
+		if (strnicmp(sb_mountdata + off, "prefixpath=", 11) == 0) {
 			off += noff;
 			continue;
 		}
-		strncat(mountdata, sb_mountdata+off, noff);
+		strncat(mountdata, sb_mountdata + off, noff);
 		off += noff;
-	}
-	strcat(mountdata, sb_mountdata+off);
+	} while (tkn_e);
+	strcat(mountdata, sb_mountdata + off);
 	mountdata[md_len] = '\0';
 
 	/* copy new IP and ref share name */
-	strcat(mountdata, ",ip=");
+	if (mountdata[strlen(mountdata) - 1] != sep)
+		strncat(mountdata, &sep, 1);
+	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);
-		}
-	}
 
-	/*cFYI(1,("%s: parent mountdata: %s", __func__,sb_mountdata));*/
-	/*cFYI(1, ("%s: submount mountdata: %s", __func__, mountdata ));*/
+	/*cifs_dbg(FYI, "%s: parent mountdata: %s\n", __func__, sb_mountdata);*/
+	/*cifs_dbg(FYI, "%s: submount mountdata: %s\n", __func__, mountdata );*/
 
 compose_mount_options_out:
 	kfree(srvIP);
 	return mountdata;
-}
 
+compose_mount_options_err:
+	kfree(mountdata);
+	mountdata = ERR_PTR(rc);
+	kfree(*devname);
+	*devname = NULL;
+	goto compose_mount_options_out;
+}
 
-static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent,
-		struct dentry *dentry, char *ref_unc)
+/**
+ * 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 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);
+	/* strip first '\' from fullpath */
+	mountdata = cifs_compose_mount_options(cifs_sb->mountdata,
+			fullpath + 1, ref, &devname);
 
 	if (IS_ERR(mountdata))
 		return (struct vfsmount *)mountdata;
@@ -211,167 +261,118 @@ static struct vfsmount *cifs_dfs_do_refmount(const struct vfsmount *mnt_parent,
 
 }
 
-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) {
-		/* we should use full path name to 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);
-		strcat(tmp_path, search_path);
-		tmp_path[l_max_len-1] = 0;
-		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:
-		dput(nd->path.dentry);
-		mntput(nd->path.mnt);
-		nd->path.mnt = newmnt;
-		nd->path.dentry = dget(newmnt->mnt_root);
-		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));
+	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);
 }
 
-
-static void*
-cifs_dfs_follow_mountpoint(struct dentry *dentry, struct nameidata *nd)
+/*
+ * 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 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;
+	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__);
+	BUG_ON(IS_ROOT(mntpt));
+
+	/*
+	 * 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.
+	 */
+	mnt = ERR_PTR(-ENOMEM);
+	full_path = build_path_from_dentry(mntpt);
+	if (full_path == NULL)
+		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;
 
-	rc = get_dfs_path(xid, ses , full_path, cifs_sb->local_nls,
+	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);
+	free_xid(xid);
+
+	cifs_put_tlink(tlink);
 
+	mnt = ERR_PTR(-ENOENT);
 	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;
+		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(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;
 	}
 
-	/* we need it cause for() above could exit without valid submount */
-	rc = PTR_ERR(mnt);
-	if (IS_ERR(mnt))
-		goto out_err;
+	/* no valid submounts were found; return error from get_dfs_path() by
+	 * preference */
+	if (rc != 0)
+		mnt = ERR_PTR(rc);
 
-	nd->path.mnt->mnt_flags |= MNT_SHRINKABLE;
-	rc = add_mount_helper(mnt, nd, &cifs_dfs_automount_list);
-
-out:
-	FreeXid(xid);
+success:
 	free_dfs_info_array(referrals, num_referrals);
+free_full_path:
 	kfree(full_path);
-	cFYI(1, ("leaving %s" , __func__));
-	return ERR_PTR(rc);
-out_err:
-	path_put(&nd->path);
-	goto out;
+cdda_exit:
+	cifs_dbg(FYI, "leaving %s\n" , __func__);
+	return mnt;
 }
 
-struct inode_operations cifs_dfs_referral_inode_operations = {
-	.follow_link = cifs_dfs_follow_mountpoint,
-};
+/*
+ * 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);
+	schedule_delayed_work(&cifs_dfs_automount_task,
+			      cifs_dfs_mountpoint_expiry_timeout);
+	cifs_dbg(FYI, "leaving %s [ok]\n" , __func__);
+	return newmnt;
+}
 
+const struct inode_operations cifs_dfs_referral_inode_operations = {
+};