12:11 p.m.
virStorageVolLookupByPath is an API call that virt-manager uses
quite a bit when dealing with storage. This call use BackendStablePath
which has several usleep() heuristics that can be tripped up
and hang virt-manager for a while.
Current example: an empty mpath pool pointing to /dev/mapper makes
_any_ calls to virStorageVolLookupByPath take 5 seconds.
The sleep heuristics are actually only needed in certain cases
when we are waiting for new storage to appear, so let's skip the
timeout steps when calling from LookupByPath.
---
src/storage/storage_backend.c | 12 ++++++++----
src/storage/storage_backend.h | 3 ++-
src/storage/storage_backend_disk.c | 2 +-
src/storage/storage_backend_scsi.c | 3 ++-
src/storage/storage_driver.c | 3 ++-
5 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/src/storage/storage_backend.c b/src/storage/storage_backend.c
index aea70e2..85b8287 100644
--- a/src/storage/storage_backend.c
+++ b/src/storage/storage_backend.c
@@ -1338,10 +1338,14 @@ virStorageBackendDetectBlockVolFormatFD(virStorageVolTargetPtr
target,
*
* Typically target.path is one of the /dev/disk/by-XXX dirs
* with stable paths.
+ *
+ * If 'wait' is true, we use a timeout loop to give dynamic paths
+ * a change to appear.
*/
char *
virStorageBackendStablePath(virStoragePoolObjPtr pool,
- const char *devpath)
+ const char *devpath,
+ bool wait)
{
DIR *dh;
struct dirent *dent;
@@ -1372,7 +1376,7 @@ virStorageBackendStablePath(virStoragePoolObjPtr pool,
reopen:
if ((dh = opendir(pool->def->target.path)) == NULL) {
opentries++;
- if (errno == ENOENT && opentries < 50) {
+ if (wait && errno == ENOENT && opentries < 50) {
usleep(100 * 1000);
goto reopen;
}
@@ -1387,7 +1391,7 @@ virStorageBackendStablePath(virStoragePoolObjPtr pool,
* the target directory and figure out which one points
* to this device node.
*
- * And it might need some time till the stabe path shows
+ * And it might need some time till the stable path shows
* up, so add timeout to retry here.
*/
retry:
@@ -1411,7 +1415,7 @@ virStorageBackendStablePath(virStoragePoolObjPtr pool,
VIR_FREE(stablepath);
}
- if (++retry < 100) {
+ if (wait && ++retry < 100) {
usleep(100 * 1000);
goto retry;
}
diff --git a/src/storage/storage_backend.h b/src/storage/storage_backend.h
index a67eeb7..71935a7 100644
--- a/src/storage/storage_backend.h
+++ b/src/storage/storage_backend.h
@@ -130,7 +130,8 @@ virStorageBackendDetectBlockVolFormatFD(virStorageVolTargetPtr
target,
int fd);
char *virStorageBackendStablePath(virStoragePoolObjPtr pool,
- const char *devpath);
+ const char *devpath,
+ bool wait);
typedef int (*virStorageBackendListVolRegexFunc)(virStoragePoolObjPtr pool,
char **const groups,
diff --git a/src/storage/storage_backend_disk.c b/src/storage/storage_backend_disk.c
index 5d9e72f..3cd4362 100644
--- a/src/storage/storage_backend_disk.c
+++ b/src/storage/storage_backend_disk.c
@@ -83,7 +83,7 @@ virStorageBackendDiskMakeDataVol(virStoragePoolObjPtr pool,
* dir every time its run. Should figure out a more efficient
* way of doing this...
*/
- vol->target.path = virStorageBackendStablePath(pool, devpath);
+ vol->target.path = virStorageBackendStablePath(pool, devpath, true);
VIR_FREE(devpath);
if (vol->target.path == NULL)
return -1;
diff --git a/src/storage/storage_backend_scsi.c b/src/storage/storage_backend_scsi.c
index 27dcbb6..4e832eb 100644
--- a/src/storage/storage_backend_scsi.c
+++ b/src/storage/storage_backend_scsi.c
@@ -246,7 +246,8 @@ virStorageBackendSCSINewLun(virStoragePoolObjPtr pool,
* way of doing this...
*/
if ((vol->target.path = virStorageBackendStablePath(pool,
- devpath)) == NULL) {
+ devpath,
+ true)) == NULL) {
retval = -1;
goto free_vol;
}
diff --git a/src/storage/storage_driver.c b/src/storage/storage_driver.c
index 28829d3..4fbc0c0 100644
--- a/src/storage/storage_driver.c
+++ b/src/storage/storage_driver.c
@@ -1318,7 +1318,8 @@ storageVolumeLookupByPath(virConnectPtr conn,
const char *stable_path;
stable_path = virStorageBackendStablePath(driver->pools.objs[i],
- cleanpath);
+ cleanpath,
+ false);
if (stable_path == NULL) {
/* Don't break the whole lookup process if it fails on
* getting the stable path for some of the pools.
--
1.7.11.7