libceph: crush_location infrastructure

Allow expressing client's location in terms of CRUSH hierarchy as
a set of (bucket type name, bucket name) pairs.  The userspace syntax
"crush_location = key1=value1 key2=value2" is incompatible with mount
options and needed adaptation.  Key-value pairs are separated by '|'
and we use ':' instead of '=' to separate keys from values.  So for:

  crush_location = host=foo rack=bar

one would write:

  crush_location=host:foo|rack:bar

As in userspace, "multipath" locations are supported, so indicating
locality for parallel hierarchies is possible:

  crush_location=rack:foo1|rack:foo2|datacenter:bar

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index a0e97f6c1072..44770b60bc38 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -176,6 +176,10 @@ int ceph_compare_options(struct ceph_options *new_opt,
 		}
 	}
 
+	ret = ceph_compare_crush_locs(&opt1->crush_locs, &opt2->crush_locs);
+	if (ret)
+		return ret;
+
 	/* any matching mon ip implies a match */
 	for (i = 0; i < opt1->num_mon; i++) {
 		if (ceph_monmap_contains(client->monc.monmap,
@@ -260,6 +264,7 @@ enum {
 	Opt_secret,
 	Opt_key,
 	Opt_ip,
+	Opt_crush_location,
 	/* string args above */
 	Opt_share,
 	Opt_crc,
@@ -274,6 +279,7 @@ static const struct fs_parameter_spec ceph_parameters[] = {
 	fsparam_flag_no ("cephx_require_signatures",	Opt_cephx_require_signatures),
 	fsparam_flag_no ("cephx_sign_messages",		Opt_cephx_sign_messages),
 	fsparam_flag_no ("crc",				Opt_crc),
+	fsparam_string	("crush_location",		Opt_crush_location),
 	fsparam_string	("fsid",			Opt_fsid),
 	fsparam_string	("ip",				Opt_ip),
 	fsparam_string	("key",				Opt_key),
@@ -298,6 +304,7 @@ struct ceph_options *ceph_alloc_options(void)
 	if (!opt)
 		return NULL;
 
+	opt->crush_locs = RB_ROOT;
 	opt->mon_addr = kcalloc(CEPH_MAX_MON, sizeof(*opt->mon_addr),
 				GFP_KERNEL);
 	if (!opt->mon_addr) {
@@ -320,6 +327,7 @@ void ceph_destroy_options(struct ceph_options *opt)
 	if (!opt)
 		return;
 
+	ceph_clear_crush_locs(&opt->crush_locs);
 	kfree(opt->name);
 	if (opt->key) {
 		ceph_crypto_key_destroy(opt->key);
@@ -454,6 +462,16 @@ int ceph_parse_param(struct fs_parameter *param, struct ceph_options *opt,
 		if (!opt->key)
 			return -ENOMEM;
 		return get_secret(opt->key, param->string, &log);
+	case Opt_crush_location:
+		ceph_clear_crush_locs(&opt->crush_locs);
+		err = ceph_parse_crush_location(param->string,
+						&opt->crush_locs);
+		if (err) {
+			error_plog(&log, "Failed to parse CRUSH location: %d",
+				   err);
+			return err;
+		}
+		break;
 
 	case Opt_osdtimeout:
 		warn_plog(&log, "Ignoring osdtimeout");
@@ -536,6 +554,7 @@ int ceph_print_client_options(struct seq_file *m, struct ceph_client *client,
 {
 	struct ceph_options *opt = client->options;
 	size_t pos = m->count;
+	struct rb_node *n;
 
 	if (opt->name) {
 		seq_puts(m, "name=");
@@ -545,6 +564,23 @@ int ceph_print_client_options(struct seq_file *m, struct ceph_client *client,
 	if (opt->key)
 		seq_puts(m, "secret=<hidden>,");
 
+	if (!RB_EMPTY_ROOT(&opt->crush_locs)) {
+		seq_puts(m, "crush_location=");
+		for (n = rb_first(&opt->crush_locs); ; ) {
+			struct crush_loc_node *loc =
+			    rb_entry(n, struct crush_loc_node, cl_node);
+
+			seq_printf(m, "%s:%s", loc->cl_loc.cl_type_name,
+				   loc->cl_loc.cl_name);
+			n = rb_next(n);
+			if (!n)
+				break;
+
+			seq_putc(m, '|');
+		}
+		seq_putc(m, ',');
+	}
+
 	if (opt->flags & CEPH_OPT_FSID)
 		seq_printf(m, "fsid=%pU,", &opt->fsid);
 	if (opt->flags & CEPH_OPT_NOSHARE)