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storage: Modify storageBackendWipeLocal to allow zero from end of device

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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.
This commit is contained in:
John Ferlan 2017-04-07 11:23:38 -04:00
parent 1acce5c853
commit 859a2d162a
1 changed files with 27 additions and 13 deletions
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40
src/storage/storage_util.c
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@ -2516,26 +2516,38 @@ static int
storageBackendWipeLocal(const char *path, storageBackendWipeLocal(const char *path,
int fd, int fd,
unsigned long long wipe_len, unsigned long long wipe_len,
size_t writebuf_length) size_t writebuf_length,
bool zero_end)
{ {
int ret = -1, written = 0; int ret = -1, written = 0;
unsigned long long remaining = 0; unsigned long long remaining = 0;
off_t size;
size_t write_size = 0; size_t write_size = 0;
char *writebuf = NULL; char *writebuf = NULL;
VIR_DEBUG("wiping start: 0 len: %llu", wipe_len);
if (VIR_ALLOC_N(writebuf, writebuf_length) < 0) if (VIR_ALLOC_N(writebuf, writebuf_length) < 0)
goto cleanup; goto cleanup;
if (lseek(fd, 0, SEEK_SET) < 0) { if (!zero_end) {
virReportSystemError(errno, if ((size = lseek(fd, 0, SEEK_SET)) < 0) {
_("Failed to seek to the start in volume " virReportSystemError(errno,
"with path '%s'"), _("Failed to seek to the start in volume "
path); "with path '%s'"),
goto cleanup; 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; remaining = wipe_len;
while (remaining > 0) { while (remaining > 0) {
@ -2573,7 +2585,8 @@ storageBackendWipeLocal(const char *path,
static int static int
storageBackendVolWipeLocalFile(const char *path, storageBackendVolWipeLocalFile(const char *path,
unsigned int algorithm, unsigned int algorithm,
unsigned long long allocation) unsigned long long allocation,
bool zero_end)
{ {
int ret = -1, fd = -1; int ret = -1, fd = -1;
const char *alg_char = NULL; 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)) { if (S_ISREG(st.st_mode) && st.st_blocks < (st.st_size / DEV_BSIZE)) {
ret = storageBackendVolZeroSparseFileLocal(path, st.st_size, fd); ret = storageBackendVolZeroSparseFileLocal(path, st.st_size, fd);
} else { } else {
ret = storageBackendWipeLocal(path, fd, allocation, st.st_blksize); ret = storageBackendWipeLocal(path, fd, allocation, st.st_blksize,
zero_end);
} }
if (ret < 0) if (ret < 0)
goto cleanup; goto cleanup;
@ -2686,7 +2700,7 @@ storageBackendVolWipePloop(virStorageVolDefPtr vol,
goto cleanup; goto cleanup;
if (storageBackendVolWipeLocalFile(target_path, algorithm, if (storageBackendVolWipeLocalFile(target_path, algorithm,
vol->target.allocation) < 0) vol->target.allocation, false) < 0)
goto cleanup; goto cleanup;
if (virFileRemove(disk_desc, 0, 0) < 0) { if (virFileRemove(disk_desc, 0, 0) < 0) {
@ -2735,7 +2749,7 @@ virStorageBackendVolWipeLocal(virConnectPtr conn ATTRIBUTE_UNUSED,
ret = storageBackendVolWipePloop(vol, algorithm); ret = storageBackendVolWipePloop(vol, algorithm);
} else { } else {
ret = storageBackendVolWipeLocalFile(vol->target.path, algorithm, ret = storageBackendVolWipeLocalFile(vol->target.path, algorithm,
vol->target.allocation); vol->target.allocation, false);
} }
return ret; return ret;