Commit ef605e86 authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Steve French
Browse files

cifs: skip trailing separators of prefix paths 



During DFS failover, prefix paths may change, so make sure to not
leave trailing separators when parsing thew in
dfs_cache_get_tgt_share().  The separators of prefix paths are already
handled by build_path_from_dentry_optional_prefix().

Consider the following DFS link:

  //dom/dfs/link: [\srv1\share\dir1, \srv2\share\dir1]

Before commit:

  mount.cifs //dom/dfs/link
  tree connect to \\srv1\share; prefix_path=dir1
  disconnect srv1; failover to srv2
  tree connect to \\srv2\share; prefix_path=dir1\
  mv foo bar

  ...
  SMB2 430 Create Request File: dir1\\foo;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request
  SMB2 582 Create Response File: dir1\\foo;GetInfo Response;Close Response
  SMB2 430 Create Request File: dir1\\bar;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request
  SMB2 286 Create Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;GetInfo Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;Close Response, Error: STATUS_OBJECT_NAME_NOT_FOUND
  SMB2 462 Create Request File: dir1\\foo;SetInfo Request FILE_INFO/SMB2_FILE_RENAME_INFO NewName:dir1\\bar;Close Request
  SMB2 478 Create Response File: dir1\\foo;SetInfo Response, Error: STATUS_OBJECT_NAME_INVALID;Close Response

After commit:

  mount.cifs //dom/dfs/link
  tree connect to \\srv1\share; prefix_path=dir1
  disconnect srv1; failover to srv2
  tree connect to \\srv2\share; prefix_path=dir1
  mv foo bar

  ...
  SMB2 430 Create Request File: dir1\foo;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request
  SMB2 582 Create Response File: dir1\foo;GetInfo Response;Close Response
  SMB2 430 Create Request File: dir1\bar;GetInfo Request FILE_INFO/SMB2_FILE_ALL_INFO;Close Request
  SMB2 286 Create Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;GetInfo Response, Error: STATUS_OBJECT_NAME_NOT_FOUND;Close Response, Error: STATUS_OBJECT_NAME_NOT_FOUND
  SMB2 462 Create Request File: dir1\foo;SetInfo Request FILE_INFO/SMB2_FILE_RENAME_INFO NewName:dir1\bar;Close Request
  SMB2 478 Create Response File: dir1\foo;SetInfo Response;Close Response

Signed-off-by: default avatarPaulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 096c956b

fs/cifs/dfs_cache.c

+49 −36
Original line number Diff line number Diff line
@@ -1229,6 +1229,30 @@ void dfs_cache_put_refsrv_sessions(const uuid_t *mount_id) 
	kref_put(&mg->refcount, mount_group_release);

}



/* Extract share from DFS target and return a pointer to prefix path or NULL */

static const char *parse_target_share(const char *target, char **share)

{

	const char *s, *seps = "/\\";

	size_t len;



	s = strpbrk(target + 1, seps);

	if (!s)

		return ERR_PTR(-EINVAL);



	len = strcspn(s + 1, seps);

	if (!len)

		return ERR_PTR(-EINVAL);

	s += len;



	len = s - target + 1;

	*share = kstrndup(target, len, GFP_KERNEL);

	if (!*share)

		return ERR_PTR(-ENOMEM);



	s = target + len;

	return s + strspn(s, seps);

}



/**

 * dfs_cache_get_tgt_share - parse a DFS target

 *
@@ -1242,56 +1266,45 @@ void dfs_cache_put_refsrv_sessions(const uuid_t *mount_id) 
int dfs_cache_get_tgt_share(char *path, const struct dfs_cache_tgt_iterator *it, char **share,

			    char **prefix)

{

	char *s, sep, *p;

	size_t len;

	size_t plen1, plen2;

	char sep;

	char *target_share, *ppath;

	const char *target_ppath, *dfsref_ppath;

	size_t target_pplen, dfsref_pplen;

	size_t len, c;



	if (!it || !path || !share || !prefix || strlen(path) < it->it_path_consumed)

		return -EINVAL;



	*share = NULL;

	*prefix = NULL;



	sep = it->it_name[0];

	if (sep != '\\' && sep != '/')

		return -EINVAL;



	s = strchr(it->it_name + 1, sep);

	if (!s)

		return -EINVAL;

	target_ppath = parse_target_share(it->it_name, &target_share);

	if (IS_ERR(target_ppath))

		return PTR_ERR(target_ppath);



	/* point to prefix in target node */

	s = strchrnul(s + 1, sep);

	/* point to prefix in DFS referral path */

	dfsref_ppath = path + it->it_path_consumed;

	dfsref_ppath += strspn(dfsref_ppath, "/\\");



	/* extract target share */

	*share = kstrndup(it->it_name, s - it->it_name, GFP_KERNEL);

	if (!*share)

		return -ENOMEM;

	target_pplen = strlen(target_ppath);

	dfsref_pplen = strlen(dfsref_ppath);



	/* skip separator */

	if (*s)

		s++;

	/* point to prefix in DFS path */

	p = path + it->it_path_consumed;

	if (*p == sep)

		p++;



	/* merge prefix paths from DFS path and target node */

	plen1 = it->it_name + strlen(it->it_name) - s;

	plen2 = path + strlen(path) - p;

	if (plen1 || plen2) {

		len = plen1 + plen2 + 2;

		*prefix = kmalloc(len, GFP_KERNEL);

		if (!*prefix) {

			kfree(*share);

			*share = NULL;

	/* merge prefix paths from DFS referral path and target node */

	if (target_pplen || dfsref_pplen) {

		len = target_pplen + dfsref_pplen + 2;

		ppath = kzalloc(len, GFP_KERNEL);

		if (!ppath) {

			kfree(target_share);

			return -ENOMEM;

		}

		if (plen1)

			scnprintf(*prefix, len, "%.*s%c%.*s", (int)plen1, s, sep, (int)plen2, p);

		else

			strscpy(*prefix, p, len);

		c = strscpy(ppath, target_ppath, len);

		if (c && dfsref_pplen)

			ppath[c] = sep;

		strlcat(ppath, dfsref_ppath, len);

	}

	*share = target_share;

	*prefix = ppath;

	return 0;

}