From 73114abb7437db2e4625a64377005ddaf8f17840 Mon Sep 17 00:00:00 2001

Message-Id: <73114abb7437db2e4625a64377005ddaf8f17840@dist-git>

From: John Ferlan <jferlan@redhat.com>

Date: Wed, 26 Apr 2017 08:41:10 -0400

Subject: [PATCH] storage: Modify storageBackendWipeLocal to allow zero from

 end of device

https://bugzilla.redhat.com/show_bug.cgi?id=1439132

Add bool 'zero_end' and logic that would allow a caller to wipe specific

portions of a target device either from the beginning (the default) or

from the end when zero_end is true.

This will allow for this code to wipe out partition table information

from a device.

(cherry picked from commit 859a2d162ac6dd141539819cfc6157724d12bde6)

Signed-off-by: John Ferlan <jferlan@redhat.com>

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 src/storage/storage_util.c | 40 +++++++++++++++++++++++++++-------------

 1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/src/storage/storage_util.c b/src/storage/storage_util.c

index adec9ab6f..8dbdc770e 100644

--- a/src/storage/storage_util.c

+++ b/src/storage/storage_util.c

@@ -2516,26 +2516,38 @@ static int

 storageBackendWipeLocal(const char *path,

                         int fd,

                         unsigned long long wipe_len,

-                        size_t writebuf_length)

+                        size_t writebuf_length,

+                        bool zero_end)

 {

     int ret = -1, written = 0;

     unsigned long long remaining = 0;

+    off_t size;

     size_t write_size = 0;

     char *writebuf = NULL;

-    VIR_DEBUG("wiping start: 0 len: %llu", wipe_len);

-

     if (VIR_ALLOC_N(writebuf, writebuf_length) < 0)

         goto cleanup;

-    if (lseek(fd, 0, SEEK_SET) < 0) {

-        virReportSystemError(errno,

-                             _("Failed to seek to the start in volume "

-                               "with path '%s'"),

-                             path);

-        goto cleanup;

+    if (!zero_end) {

+        if ((size = lseek(fd, 0, SEEK_SET)) < 0) {

+            virReportSystemError(errno,

+                                 _("Failed to seek to the start in volume "

+                                   "with path '%s'"),

+                                 path);

+            goto cleanup;

+        }

+    } else {

+        if ((size = lseek(fd, -wipe_len, SEEK_END)) < 0) {

+            virReportSystemError(errno,

+                                 _("Failed to seek to %llu bytes to the end "

+                                   "in volume with path '%s'"),

+                                 wipe_len, path);

+            goto cleanup;

+        }

     }

+    VIR_DEBUG("wiping start: %zd len: %llu", (ssize_t) size, wipe_len);

+

     remaining = wipe_len;

     while (remaining > 0) {

@@ -2573,7 +2585,8 @@ storageBackendWipeLocal(const char *path,

 static int

 storageBackendVolWipeLocalFile(const char *path,

                                unsigned int algorithm,

-                               unsigned long long allocation)

+                               unsigned long long allocation,

+                               bool zero_end)

 {

     int ret = -1, fd = -1;

     const char *alg_char = NULL;

@@ -2648,7 +2661,8 @@ storageBackendVolWipeLocalFile(const char *path,

         if (S_ISREG(st.st_mode) && st.st_blocks < (st.st_size / DEV_BSIZE)) {

             ret = storageBackendVolZeroSparseFileLocal(path, st.st_size, fd);

         } else {

-            ret = storageBackendWipeLocal(path, fd, allocation, st.st_blksize);

+            ret = storageBackendWipeLocal(path, fd, allocation, st.st_blksize,

+                                          zero_end);

         }

         if (ret < 0)

             goto cleanup;

@@ -2686,7 +2700,7 @@ storageBackendVolWipePloop(virStorageVolDefPtr vol,

         goto cleanup;

     if (storageBackendVolWipeLocalFile(target_path, algorithm,

-                                       vol->target.allocation) < 0)

+                                       vol->target.allocation, false) < 0)

         goto cleanup;

     if (virFileRemove(disk_desc, 0, 0) < 0) {

@@ -2735,7 +2749,7 @@ virStorageBackendVolWipeLocal(virConnectPtr conn ATTRIBUTE_UNUSED,

         ret = storageBackendVolWipePloop(vol, algorithm);

     } else {

         ret = storageBackendVolWipeLocalFile(vol->target.path, algorithm,

-                                             vol->target.allocation);

+                                             vol->target.allocation, false);

     }

     return ret;

-- 

2.12.2