Zeroout whole ppl space during creation/force assemble

[thirdparty/mdadm.git] / util.c

diff --git a/util.c b/util.c
index 68af38193e117c6cfec5af40d67ccda348dbd1d3..c11729e3260ed38a8be54021e525f0b31ecadddf 100644 (file)
--- a/util.c
+++ b/util.c
@@ -30,6 +30,7 @@
 #include       <sys/un.h>
 #include       <sys/resource.h>
 #include       <sys/vfs.h>
+#include       <sys/mman.h>
 #include       <linux/magic.h>
 #include       <poll.h>
 #include       <ctype.h>
@@ -2334,3 +2335,51 @@ void set_hooks(void)
        set_dlm_hooks();
        set_cmap_hooks();
 }
+
+int zero_disk_range(int fd, unsigned long long sector, size_t count)
+{
+       int ret = 0;
+       int fd_zero;
+       void *addr = NULL;
+       size_t written = 0;
+       size_t len = count * 512;
+       ssize_t n;
+
+       fd_zero = open("/dev/zero", O_RDONLY);
+       if (fd_zero < 0) {
+               pr_err("Cannot open /dev/zero\n");
+               return -1;
+       }
+
+       if (lseek64(fd, sector * 512, SEEK_SET) < 0) {
+               ret = -errno;
+               pr_err("Failed to seek offset for zeroing\n");
+               goto out;
+       }
+
+       addr = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd_zero, 0);
+
+       if (addr == MAP_FAILED) {
+               ret = -errno;
+               pr_err("Mapping /dev/zero failed\n");
+               goto out;
+       }
+
+       do {
+               n = write(fd, addr + written, len - written);
+               if (n < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       ret = -errno;
+                       pr_err("Zeroing disk range failed\n");
+                       break;
+               }
+               written += n;
+       } while (written != len);
+
+       munmap(addr, len);
+
+out:
+       close(fd_zero);
+       return ret;
+}