Currently libvirt can race with udev

creation of /dev/disk/by-{id,path}, so if we fail to open the directory, retry
up to 5 seconds.  This is only likely to happen on hosts that are:

1) diskless (so /dev/disk/by-{id,path} doesn't exist already), and
2) slow, and/or heavily loaded (meaning that udev can take some time to create
the /dev nodes).

Signed-off-by: Chris Lalancette <clalance@redhat.com>
This commit is contained in:
Chris Lalancette 2008-11-28 07:42:21 +00:00
parent 431d40fa9c
commit d20d6b1bb0
2 changed files with 19 additions and 4 deletions

View File

@ -1,3 +1,7 @@
Fri Nov 28 08:40:00 CET 2008 Chris Lalancette <clalance@redhat.com>
* src/storage_backend.c: Wait up to 5 seconds for
/dev/disk/by-{id,path} to exist in virStorageBackendStablePath
Thu Nov 27 17:15:10 CET 2008 Daniel Veillard <veillard@redhat.com>
* src/xen_unified.c: use preferably xend method to update

View File

@ -291,6 +291,7 @@ virStorageBackendStablePath(virConnectPtr conn,
DIR *dh;
struct dirent *dent;
char *stablepath;
int opentries = 0;
/* Short circuit if pool has no target, or if its /dev */
if (pool->def->target.path == NULL ||
@ -304,12 +305,17 @@ virStorageBackendStablePath(virConnectPtr conn,
if (!STRPREFIX(pool->def->target.path, "/dev"))
goto ret_strdup;
/* The pool is pointing somewhere like /dev/disk/by-path
* or /dev/disk/by-id, so we need to check all symlinks in
* the target directory and figure out which one points
* to this device node
/* We loop here because /dev/disk/by-{id,path} may not have existed
* before we started this operation, so we have to give it some time to
* get created.
*/
reopen:
if ((dh = opendir(pool->def->target.path)) == NULL) {
opentries++;
if (errno == ENOENT && opentries < 50) {
usleep(100 * 1000);
goto reopen;
}
virStorageReportError(conn, VIR_ERR_INTERNAL_ERROR,
_("cannot read dir %s: %s"),
pool->def->target.path,
@ -317,6 +323,11 @@ virStorageBackendStablePath(virConnectPtr conn,
return NULL;
}
/* The pool is pointing somewhere like /dev/disk/by-path
* or /dev/disk/by-id, so we need to check all symlinks in
* the target directory and figure out which one points
* to this device node
*/
while ((dent = readdir(dh)) != NULL) {
if (dent->d_name[0] == '.')
continue;