mkswap: clear 1st kilobyte. Closes bug 1831

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-08-31 01:50:03 +02:00
parent c71ec70616
commit 4e7dd3c363

View File

@ -102,7 +102,15 @@ int mkswap_main(int argc UNUSED_PARAM, char **argv)
printf("Setting up swapspace version 1, size = %"OFF_FMT"u bytes\n", len);
mkswap_selinux_setcontext(fd, argv[0]);
/* Make a header. hdr is zero-filled so far... */
/* hdr is zero-filled so far. Clear the first kbyte, or else
* mkswap-ing former FAT partition does NOT erase its signature.
*
* util-linux-ng 2.17.2 claims to erase it only if it does not see
* a partition table and is not run on whole disk. -f forces it.
*/
xwrite(fd, hdr, 1024);
/* Fill the header. */
hdr->version = 1;
hdr->last_page = (uoff_t)len / pagesize;
@ -123,7 +131,6 @@ int mkswap_main(int argc UNUSED_PARAM, char **argv)
/* Write the header. Sync to disk because some kernel versions check
* signature on disk (not in cache) during swapon. */
xlseek(fd, 1024, SEEK_SET);
xwrite(fd, hdr, NWORDS * 4);
xlseek(fd, pagesize - 10, SEEK_SET);
xwrite(fd, SWAPSPACE2, 10);