device_id: more use of device_get_uuid

Use function that is caching UUID if kernel provides functionality
from a single ioctl() call.

lib/device/device_id.c

@@ -25,6 +25,8 @@
 #include "lib/cache/lvmcache.h"
 #include "lib/datastruct/str_list.h"
 #include "lib/metadata/metadata-exported.h"
+#include "lib/activate/activate.h"
+#include "device_mapper/misc/dm-ioctl.h"
 
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -506,56 +508,57 @@ static int _dm_uuid_has_prefix(char *sysbuf, const char *prefix)
 /* the dm uuid uses the wwid of the underlying dev */
 int dev_has_mpath_uuid(struct cmd_context *cmd, struct device *dev, const char **idname_out)
 {
- char sysbuf[PATH_MAX] = { 0 };
+
+ char uuid[DM_UUID_LEN];
  const char *idname;
 
- if (!read_sys_block(cmd, dev, "dm/uuid", sysbuf, sizeof(sysbuf)))
- return 0;
+ if (!device_get_uuid(cmd, MAJOR(dev->dev), MINOR(dev->dev), uuid, sizeof(uuid)))
+ return_0;
 
- if (!_dm_uuid_has_prefix(sysbuf, "mpath-"))
+ if (!_dm_uuid_has_prefix(uuid, "mpath-"))
  return 0;
 
  if (!idname_out)
  return 1;
- if (!(idname = strdup(sysbuf)))
+ if (!(idname = strdup(uuid)))
  return_0;
  *idname_out = idname;
  return 1;
 }
 
 static int _dev_has_crypt_uuid(struct cmd_context *cmd, struct device *dev, const char **idname_out)
 {
- char sysbuf[PATH_MAX] = { 0 };
+ char uuid[DM_UUID_LEN];
  const char *idname;
 
- if (!read_sys_block(cmd, dev, "dm/uuid", sysbuf, sizeof(sysbuf)))
- return 0;
+ if (!device_get_uuid(cmd, MAJOR(dev->dev), MINOR(dev->dev), uuid, sizeof(uuid)))
+ return_0;
 
- if (!_dm_uuid_has_prefix(sysbuf, "CRYPT-"))
+ if (!_dm_uuid_has_prefix(uuid, "CRYPT-"))
  return 0;
 
  if (!idname_out)
  return 1;
- if (!(idname = strdup(sysbuf)))
+ if (!(idname = strdup(uuid)))
  return_0;
  *idname_out = idname;
  return 1;
 }
 
 static int _dev_has_lvmlv_uuid(struct cmd_context *cmd, struct device *dev, const char **idname_out)
 {
- char sysbuf[PATH_MAX] = { 0 };
+ char uuid[DM_UUID_LEN];
  const char *idname;
 
- if (!read_sys_block(cmd, dev, "dm/uuid", sysbuf, sizeof(sysbuf)))
- return 0;
+ if (!device_get_uuid(cmd, MAJOR(dev->dev), MINOR(dev->dev), uuid, sizeof(uuid)))
+ return_0;
 
- if (!_dm_uuid_has_prefix(sysbuf, "LVM-"))
+ if (!_dm_uuid_has_prefix(uuid, UUID_PREFIX))
  return 0;
 
  if (!idname_out)
  return 1;
- if (!(idname = strdup(sysbuf)))
+ if (!(idname = strdup(uuid)))
  return_0;
  *idname_out = idname;
  return 1;
@@ -773,49 +776,36 @@ const char *device_id_system_read(struct cmd_context *cmd, struct device *dev, u
  struct dev_wwid *dw;
  unsigned i;
 
- if (idtype == DEV_ID_TYPE_SYS_WWID)
+ switch (idtype) {
+ case DEV_ID_TYPE_SYS_WWID:
  dev_read_sys_wwid(cmd, dev, sysbuf, sizeof(sysbuf), NULL);
-
- else if (idtype == DEV_ID_TYPE_SYS_SERIAL)
+ break;
+ case DEV_ID_TYPE_SYS_SERIAL:
  _dev_read_sys_serial(cmd, dev, sysbuf, sizeof(sysbuf));
-
- else if (idtype == DEV_ID_TYPE_MPATH_UUID) {
- read_sys_block(cmd, dev, "dm/uuid", sysbuf, sizeof(sysbuf));
- /* if (strncmp(sysbuf, "mpath", 5)) sysbuf[0] = '\0'; */
- }
-
- else if (idtype == DEV_ID_TYPE_CRYPT_UUID) {
- read_sys_block(cmd, dev, "dm/uuid", sysbuf, sizeof(sysbuf));
- /* if (strncmp(sysbuf, "CRYPT", 5)) sysbuf[0] = '\0'; */
- }
-
- else if (idtype == DEV_ID_TYPE_LVMLV_UUID) {
- read_sys_block(cmd, dev, "dm/uuid", sysbuf, sizeof(sysbuf));
- /* if (strncmp(sysbuf, "LVM", 3)) sysbuf[0] = '\0'; */
- }
-
- else if (idtype == DEV_ID_TYPE_MD_UUID) {
+ break;
+ case DEV_ID_TYPE_MPATH_UUID:
+ case DEV_ID_TYPE_CRYPT_UUID:
+ case DEV_ID_TYPE_LVMLV_UUID:
+ (void)device_get_uuid(cmd, MAJOR(dev->dev), MINOR(dev->dev), sysbuf, sizeof(sysbuf));
+ break;
+ case DEV_ID_TYPE_MD_UUID:
  read_sys_block(cmd, dev, "md/uuid", sysbuf, sizeof(sysbuf));
- }
-
- else if (idtype == DEV_ID_TYPE_LOOP_FILE) {
+ break;
+ case DEV_ID_TYPE_LOOP_FILE:
  read_sys_block(cmd, dev, "loop/backing_file", sysbuf, sizeof(sysbuf));
  /* if backing file is deleted, fall back to devname */
  if (strstr(sysbuf, "(deleted)"))
  sysbuf[0] = '\0';
- }
-
- else if (idtype == DEV_ID_TYPE_DEVNAME) {
+ break;
+ case DEV_ID_TYPE_DEVNAME:
  if (dm_list_empty(&dev->aliases))
  goto_bad;
  if (!(idname = strdup(dev_name(dev))))
  goto_bad;
  return idname;
- }
-
- else if (idtype == DEV_ID_TYPE_WWID_NAA ||
- idtype == DEV_ID_TYPE_WWID_EUI ||
- idtype == DEV_ID_TYPE_WWID_T10) {
+ case DEV_ID_TYPE_WWID_NAA:
+ case DEV_ID_TYPE_WWID_EUI:
+ case DEV_ID_TYPE_WWID_T10:
  if (!(dev->flags & DEV_ADDED_VPD_WWIDS))
  dev_read_vpd_wwids(cmd, dev);
  dm_list_iterate_items(dw, &dev->wwids) {
@@ -1015,7 +1005,7 @@ static int _dev_has_stable_id(struct cmd_context *cmd, struct device *dev)
  }
 
  if ((MAJOR(dev->dev) == cmd->dev_types->device_mapper_major)) {
- if (!read_sys_block(cmd, dev, "dm/uuid", sysbuf, sizeof(sysbuf)))
+ if (!device_get_uuid(cmd, MAJOR(dev->dev), MINOR(dev->dev), sysbuf, sizeof(sysbuf)))
  goto_out;
 
  if (_dm_uuid_has_prefix(sysbuf, "mpath-"))