Commit 8ad44d5e authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

libceph: read_from_replica option 



Expose replica reads through read_from_replica=balance and
read_from_replica=localize.  The default is to read from primary
(read_from_replica=no).

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
parent 117d96a0

include/linux/ceph/libceph.h

+2 −0
Original line number Diff line number Diff line
@@ -53,6 +53,8 @@ struct ceph_options { 
	unsigned long osd_keepalive_timeout;	/* jiffies */

	unsigned long osd_request_timeout;	/* jiffies */



	u32 osd_req_flags;  /* CEPH_OSD_FLAG_*, applied to each OSD request */



	/*

	 * any type that can't be simply compared or doesn't need

	 * to be compared should go beyond this point,

net/ceph/ceph_common.c

+39 −0
Original line number Diff line number Diff line
@@ -265,6 +265,7 @@ enum { 
	Opt_key,

	Opt_ip,

	Opt_crush_location,

	Opt_read_from_replica,

	/* string args above */

	Opt_share,

	Opt_crc,
@@ -274,6 +275,19 @@ enum { 
	Opt_abort_on_full,

};



enum {

	Opt_read_from_replica_no,

	Opt_read_from_replica_balance,

	Opt_read_from_replica_localize,

};



static const struct constant_table ceph_param_read_from_replica[] = {

	{"no",		Opt_read_from_replica_no},

	{"balance",	Opt_read_from_replica_balance},

	{"localize",	Opt_read_from_replica_localize},

	{}

};



static const struct fs_parameter_spec ceph_parameters[] = {

	fsparam_flag	("abort_on_full",		Opt_abort_on_full),

	fsparam_flag_no ("cephx_require_signatures",	Opt_cephx_require_signatures),
@@ -290,6 +304,8 @@ static const struct fs_parameter_spec ceph_parameters[] = { 
	fsparam_u32	("osdkeepalive",		Opt_osdkeepalivetimeout),

	__fsparam	(fs_param_is_s32, "osdtimeout", Opt_osdtimeout,

			 fs_param_deprecated, NULL),

	fsparam_enum	("read_from_replica",		Opt_read_from_replica,

			 ceph_param_read_from_replica),

	fsparam_string	("secret",			Opt_secret),

	fsparam_flag_no ("share",			Opt_share),

	fsparam_flag_no ("tcp_nodelay",			Opt_tcp_nodelay),
@@ -472,6 +488,24 @@ int ceph_parse_param(struct fs_parameter *param, struct ceph_options *opt, 
			return err;

		}

		break;

	case Opt_read_from_replica:

		switch (result.uint_32) {

		case Opt_read_from_replica_no:

			opt->osd_req_flags &= ~(CEPH_OSD_FLAG_BALANCE_READS |

						CEPH_OSD_FLAG_LOCALIZE_READS);

			break;

		case Opt_read_from_replica_balance:

			opt->osd_req_flags |= CEPH_OSD_FLAG_BALANCE_READS;

			opt->osd_req_flags &= ~CEPH_OSD_FLAG_LOCALIZE_READS;

			break;

		case Opt_read_from_replica_localize:

			opt->osd_req_flags |= CEPH_OSD_FLAG_LOCALIZE_READS;

			opt->osd_req_flags &= ~CEPH_OSD_FLAG_BALANCE_READS;

			break;

		default:

			BUG();

		}

		break;



	case Opt_osdtimeout:

		warn_plog(&log, "Ignoring osdtimeout");
@@ -580,6 +614,11 @@ int ceph_print_client_options(struct seq_file *m, struct ceph_client *client, 
		}

		seq_putc(m, ',');

	}

	if (opt->osd_req_flags & CEPH_OSD_FLAG_BALANCE_READS) {

		seq_puts(m, "read_from_replica=balance,");

	} else if (opt->osd_req_flags & CEPH_OSD_FLAG_LOCALIZE_READS) {

		seq_puts(m, "read_from_replica=localize,");

	}



	if (opt->flags & CEPH_OPT_FSID)

		seq_printf(m, "fsid=%pU,", &opt->fsid);

net/ceph/osd_client.c

+4 −1
Original line number Diff line number Diff line
@@ -2425,11 +2425,14 @@ static void __submit_request(struct ceph_osd_request *req, bool wrlocked) 


static void account_request(struct ceph_osd_request *req)

{

	struct ceph_osd_client *osdc = req->r_osdc;



	WARN_ON(req->r_flags & (CEPH_OSD_FLAG_ACK | CEPH_OSD_FLAG_ONDISK));

	WARN_ON(!(req->r_flags & (CEPH_OSD_FLAG_READ | CEPH_OSD_FLAG_WRITE)));



	req->r_flags |= CEPH_OSD_FLAG_ONDISK;

	atomic_inc(&req->r_osdc->num_requests);

	req->r_flags |= osdc->client->options->osd_req_flags;

	atomic_inc(&osdc->num_requests);



	req->r_start_stamp = jiffies;

	req->r_start_latency = ktime_get();