Test for holes in swapfiles

 -Erik

diff --git a/util-linux/swaponoff.c b/util-linux/swaponoff.c
index a57dfe472be95d0109740f1eab7e70b84b4f7958..918a5bc0e6ce32682c765e021290ee0521edbc12 100644 (file)
--- a/util-linux/swaponoff.c
+++ b/util-linux/swaponoff.c
@@ -48,6 +48,18 @@ static const int SWAPOFF_APP = 1;
 static int swap_enable_disable(const char *device)
 {
        int status;
+       struct stat st;
+
+       if (stat(device, &st) < 0) {
+               perror_msg_and_die("cannot stat %s");
+       }
+
+       /* test for holes */
+       if (S_ISREG(st.st_mode)) {
+               if (st.st_blocks * 512 < st.st_size) {
+                       error_msg_and_die("swap file has holes");
+               }
+       }
 
        if (whichApp == SWAPON_APP)
                status = swapon(device, 0);