From b251424242b46d62f666829c0e7a7550768fc8de Mon Sep 17 00:00:00 2001
From: Pawel Baldysiak <pawel.baldysiak@intel.com>
Date: Thu, 28 Sep 2017 14:41:11 +0200
Subject: [PATCH 05/12] Zeroout whole ppl space during creation/force
 assemble

PPL area should be cleared before creation/force assemble.
If the drive was used in other RAID array, it might contains PPL from it.
There is a risk that mdadm recognizes those PPLs and
refuses to assemble the RAID due to PPL conflict with created
array.

Signed-off-by: Pawel Baldysiak <pawel.baldysiak@intel.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>
---
 mdadm.h       |  1 +
 super-intel.c |  7 ++++++-
 super1.c      |  5 +++++
 util.c        | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/mdadm.h b/mdadm.h
index 3fc8a4f..85947bf 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -687,6 +687,7 @@ extern int sysfs_unique_holder(char *devnm, long rdev);
 extern int sysfs_freeze_array(struct mdinfo *sra);
 extern int sysfs_wait(int fd, int *msec);
 extern int load_sys(char *path, char *buf, int len);
+extern int zero_disk_range(int fd, unsigned long long sector, size_t count);
 extern int reshape_prepare_fdlist(char *devname,
 				  struct mdinfo *sra,
 				  int raid_disks,
diff --git a/super-intel.c b/super-intel.c
index 56dec36..65cdc92 100644
--- a/super-intel.c
+++ b/super-intel.c
@@ -6065,7 +6065,12 @@ static int write_init_ppl_imsm(struct supertype *st, struct mdinfo *info, int fd
 	struct ppl_header *ppl_hdr;
 	int ret;
 
-	ret = posix_memalign(&buf, 4096, PPL_HEADER_SIZE);
+	/* first clear entire ppl space */
+	ret = zero_disk_range(fd, info->ppl_sector, info->ppl_size);
+	if (ret)
+		return ret;
+
+	ret = posix_memalign(&buf, MAX_SECTOR_SIZE, PPL_HEADER_SIZE);
 	if (ret) {
 		pr_err("Failed to allocate PPL header buffer\n");
 		return ret;
diff --git a/super1.c b/super1.c
index f80e38a..7ae6dc3 100644
--- a/super1.c
+++ b/super1.c
@@ -1823,6 +1823,11 @@ static int write_init_ppl1(struct supertype *st, struct mdinfo *info, int fd)
 	struct ppl_header *ppl_hdr;
 	int ret;
 
+	/* first clear entire ppl space */
+	ret = zero_disk_range(fd, info->ppl_sector, info->ppl_size);
+	if (ret)
+		return ret;
+
 	ret = posix_memalign(&buf, 4096, PPL_HEADER_SIZE);
 	if (ret) {
 		pr_err("Failed to allocate PPL header buffer\n");
diff --git a/util.c b/util.c
index 68af381..c11729e 100644
--- 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;
+}
-- 
2.7.4