afs: Implement VL server rotation
Track VL servers as independent entities rather than lumping all their
addresses together into one set and implement server-level rotation by:
(1) Add the concept of a VL server list, where each server has its own
separate address list. This code is similar to the FS server list.
(2) Use the DNS resolver to retrieve a set of servers and their associated
addresses, ports, preference and weight ratings.
(3) In the case of a legacy DNS resolver or an address list given directly
through /proc/net/afs/cells, create a list containing just a dummy
server record and attach all the addresses to that.
(4) Implement a simple rotation policy, for the moment ignoring the
priorities and weights assigned to the servers.
(5) Show the address list through /proc/net/afs/<cell>/vlservers. This
also displays the source and status of the data as indicated by the
upcall.
Signed-off-by: David Howells <dhowells@redhat.com>
diff --git a/fs/afs/volume.c b/fs/afs/volume.c
index 3037bd0..1cd263f 100644
--- a/fs/afs/volume.c
+++ b/fs/afs/volume.c
@@ -74,55 +74,35 @@ static struct afs_vldb_entry *afs_vl_lookup_vldb(struct afs_cell *cell,
const char *volname,
size_t volnamesz)
{
- struct afs_addr_cursor ac;
- struct afs_vldb_entry *vldb;
+ struct afs_vldb_entry *vldb = ERR_PTR(-EDESTADDRREQ);
+ struct afs_vl_cursor vc;
int ret;
- ret = afs_set_vl_cursor(&ac, cell);
- if (ret < 0)
- return ERR_PTR(ret);
+ if (!afs_begin_vlserver_operation(&vc, cell, key))
+ return ERR_PTR(-ERESTARTSYS);
- while (afs_iterate_addresses(&ac)) {
- if (!test_bit(ac.index, &ac.alist->probed)) {
- ret = afs_vl_get_capabilities(cell->net, &ac, key);
+ while (afs_select_vlserver(&vc)) {
+ if (!test_bit(vc.ac.index, &vc.ac.alist->probed)) {
+ ret = afs_vl_get_capabilities(cell->net, &vc.ac, key);
switch (ret) {
case VL_SERVICE:
- clear_bit(ac.index, &ac.alist->yfs);
- set_bit(ac.index, &ac.alist->probed);
- ac.addr->srx_service = ret;
+ clear_bit(vc.ac.index, &vc.ac.alist->yfs);
+ set_bit(vc.ac.index, &vc.ac.alist->probed);
+ vc.ac.addr->srx_service = ret;
break;
case YFS_VL_SERVICE:
- set_bit(ac.index, &ac.alist->yfs);
- set_bit(ac.index, &ac.alist->probed);
- ac.addr->srx_service = ret;
+ set_bit(vc.ac.index, &vc.ac.alist->yfs);
+ set_bit(vc.ac.index, &vc.ac.alist->probed);
+ vc.ac.addr->srx_service = ret;
break;
}
}
- vldb = afs_vl_get_entry_by_name_u(cell->net, &ac, key,
- volname, volnamesz);
- switch (ac.error) {
- case 0:
- afs_end_cursor(&ac);
- return vldb;
- case -ECONNABORTED:
- ac.error = afs_abort_to_error(ac.abort_code);
- goto error;
- case -ENOMEM:
- case -ENONET:
- goto error;
- case -ENETUNREACH:
- case -EHOSTUNREACH:
- case -ECONNREFUSED:
- break;
- default:
- ac.error = -EIO;
- goto error;
- }
+ vldb = afs_vl_get_entry_by_name_u(&vc, volname, volnamesz);
}
-error:
- return ERR_PTR(afs_end_cursor(&ac));
+ ret = afs_end_vlserver_operation(&vc);
+ return ret < 0 ? ERR_PTR(ret) : vldb;
}
/*
