fs: dlm: change allocation limits

While running tcpkill I experienced invalid header length values while
receiving to check that a node doesn't try to send a invalid dlm message
we also check on applications minimum allocation limit. Also use
DEFAULT_BUFFER_SIZE as maximum allocation limit. The define
LOWCOMMS_MAX_TX_BUFFER_LEN is to calculate maximum buffer limits on
application layer, future midcomms layer will subtract their needs from
this define.

Signed-off-by: Alexander Aring <aahringo@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 4f2245e..206bd30 100644 (file)
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -1376,9 +1376,11 @@ void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
        struct writequeue_entry *e;
        int offset = 0;
 
-       if (len > LOWCOMMS_MAX_TX_BUFFER_LEN) {
-               BUILD_BUG_ON(PAGE_SIZE < LOWCOMMS_MAX_TX_BUFFER_LEN);
+       if (len > DEFAULT_BUFFER_SIZE ||
+           len < sizeof(struct dlm_header)) {
+               BUILD_BUG_ON(PAGE_SIZE < DEFAULT_BUFFER_SIZE);
                log_print("failed to allocate a buffer of size %d", len);
+               WARN_ON(1);
                return NULL;
        }