Re: [libvirt] [PATCH]: Give /dev/disk/by-{id,path} a chance to exist

All, When refreshing a storage pool (say, an iSCSI pool), one of the things it does is to generate the stable path for each of the LUNs via virStorageBackendStablePath. That, in turn, has the following code:

Index: src/storage_backend.c =================================================================== RCS file: /data/cvs/libvirt/src/storage_backend.c,v retrieving revision 1.29 diff -u -r1.29 storage_backend.c --- a/src/storage_backend.c 17 Nov 2008 11:19:33 -0000 1.29 +++ b/src/storage_backend.c 25 Nov 2008 15:14:20 -0000 @@ -291,6 +291,7 @@ DIR *dh; struct dirent *dent; char *stablepath; + int opentries; /* Short circuit if pool has no target, or if its /dev */ if (pool->def->target.path == NULL || @@ -304,19 +305,33 @@ 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. */ - if ((dh = opendir(pool->def->target.path)) == NULL) { + dh = NULL; + opentries = 0; + while (opentries < 50) { + if ((dh = opendir(pool->def->target.path)) != NULL) + break; + + usleep(100 * 1000); + opentries++; + }