fix memory leak in CIFSFindNext

When CIFSFindNext gets back an -EBADF from a call, it sets the return
code of the function to 0 and eventually exits. Doing this makes the
cleanup at the end of the function skip freeing the SMB buffer, so
we need to make sure we free the buffer explicitly when doing this.

If we don't you end up with errors like this when unplugging the cifs
kernel module:

slab error in kmem_cache_destroy(): cache `cifs_request': Can't free all objects
 [<c046bdbf>] kmem_cache_destroy+0x61/0xf3
 [<e0f03045>] cifs_destroy_request_bufs+0x14/0x28 [cifs]
 [<e0f2016e>] exit_cifs+0x1e/0x80 [cifs]
 [<c043aeae>] sys_delete_module+0x192/0x1b8
 [<c04451fd>] audit_syscall_entry+0x14b/0x17d
 [<c0405413>] syscall_call+0x7/0xb
 =======================
Signed-off-by: NJeff Layton <jlayton@redhat.com>

fs/cifs/CHANGES

@@ -12,7 +12,8 @@ Add ability to modify cifs acls for handling chmod (when mounted with
 cifsacl flag). Fix prefixpath path separator so we can handle mounts
 with prefixpaths longer than one directory (one path component) when
 mounted to Windows servers.  Fix slow file open when cifsacl
-enabled.
+enabled. Fix memory leak in FindNext when the SMB call returns -EBADF.
+
 
 Version 1.51
 ------------

fs/cifs/cifssmb.c

@@ -3679,6 +3679,7 @@ int CIFSFindNext(const int xid, struct cifsTconInfo *tcon,
 	if (rc) {
 		if (rc == -EBADF) {
 			psrch_inf->endOfSearch = true;
+			cifs_buf_release(pSMB);
 			rc = 0; /* search probably was closed at end of search*/
 		} else
 			cFYI(1, ("FindNext returned = %d", rc));