rbd: use watch/notify for changes in rbd header
Send notifications when we change the rbd header (e.g. create a snapshot)
and wait for such notifications. This allows synchronizing the snapshot
creation between different rbd clients/rools.
Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index e1e38b1..16dc364 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -31,6 +31,7 @@
#include <linux/ceph/osd_client.h>
#include <linux/ceph/mon_client.h>
#include <linux/ceph/decode.h>
+#include <linux/parser.h>
#include <linux/kernel.h>
#include <linux/device.h>
@@ -54,6 +55,8 @@
#define DEV_NAME_LEN 32
+#define RBD_NOTIFY_TIMEOUT_DEFAULT 10
+
/*
* block device image metadata (in-memory version)
*/
@@ -71,6 +74,12 @@
char *snap_names;
u64 *snap_sizes;
+
+ u64 obj_version;
+};
+
+struct rbd_options {
+ int notify_timeout;
};
/*
@@ -78,6 +87,7 @@
*/
struct rbd_client {
struct ceph_client *client;
+ struct rbd_options *rbd_opts;
struct kref kref;
struct list_head node;
};
@@ -124,6 +134,9 @@
char pool_name[RBD_MAX_POOL_NAME_LEN];
int poolid;
+ struct ceph_osd_event *watch_event;
+ struct ceph_osd_request *watch_request;
+
char snap_name[RBD_MAX_SNAP_NAME_LEN];
u32 cur_snap; /* index+1 of current snapshot within snap context
0 - for the head */
@@ -177,6 +190,8 @@
put_device(&rbd_dev->dev);
}
+static int __rbd_update_snaps(struct rbd_device *rbd_dev);
+
static int rbd_open(struct block_device *bdev, fmode_t mode)
{
struct gendisk *disk = bdev->bd_disk;
@@ -211,7 +226,8 @@
* Initialize an rbd client instance.
* We own *opt.
*/
-static struct rbd_client *rbd_client_create(struct ceph_options *opt)
+static struct rbd_client *rbd_client_create(struct ceph_options *opt,
+ struct rbd_options *rbd_opts)
{
struct rbd_client *rbdc;
int ret = -ENOMEM;
@@ -233,6 +249,8 @@
if (ret < 0)
goto out_err;
+ rbdc->rbd_opts = rbd_opts;
+
spin_lock(&node_lock);
list_add_tail(&rbdc->node, &rbd_client_list);
spin_unlock(&node_lock);
@@ -267,6 +285,59 @@
}
/*
+ * mount options
+ */
+enum {
+ Opt_notify_timeout,
+ Opt_last_int,
+ /* int args above */
+ Opt_last_string,
+ /* string args above */
+};
+
+static match_table_t rbdopt_tokens = {
+ {Opt_notify_timeout, "notify_timeout=%d"},
+ /* int args above */
+ /* string args above */
+ {-1, NULL}
+};
+
+static int parse_rbd_opts_token(char *c, void *private)
+{
+ struct rbd_options *rbdopt = private;
+ substring_t argstr[MAX_OPT_ARGS];
+ int token, intval, ret;
+
+ token = match_token((char *)c, rbdopt_tokens, argstr);
+ if (token < 0)
+ return -EINVAL;
+
+ if (token < Opt_last_int) {
+ ret = match_int(&argstr[0], &intval);
+ if (ret < 0) {
+ pr_err("bad mount option arg (not int) "
+ "at '%s'\n", c);
+ return ret;
+ }
+ dout("got int token %d val %d\n", token, intval);
+ } else if (token > Opt_last_int && token < Opt_last_string) {
+ dout("got string token %d val %s\n", token,
+ argstr[0].from);
+ } else {
+ dout("got token %d\n", token);
+ }
+
+ switch (token) {
+ case Opt_notify_timeout:
+ rbdopt->notify_timeout = intval;
+ break;
+ default:
+ BUG_ON(token);
+ }
+ return 0;
+}
+
+/*
* Get a ceph client with specific addr and configuration, if one does
* not exist create it.
*/
@@ -276,11 +347,18 @@
struct rbd_client *rbdc;
struct ceph_options *opt;
int ret;
+ struct rbd_options *rbd_opts;
+
+ rbd_opts = kzalloc(sizeof(*rbd_opts), GFP_KERNEL);
+ if (!rbd_opts)
+ return -ENOMEM;
+
+ rbd_opts->notify_timeout = RBD_NOTIFY_TIMEOUT_DEFAULT;
ret = ceph_parse_options(&opt, options, mon_addr,
- mon_addr + strlen(mon_addr), NULL, NULL);
+ mon_addr + strlen(mon_addr), parse_rbd_opts_token, rbd_opts);
if (ret < 0)
- return ret;
+ goto done_err;
spin_lock(&node_lock);
rbdc = __rbd_client_find(opt);
@@ -296,13 +374,18 @@
}
spin_unlock(&node_lock);
- rbdc = rbd_client_create(opt);
- if (IS_ERR(rbdc))
- return PTR_ERR(rbdc);
+ rbdc = rbd_client_create(opt, rbd_opts);
+ if (IS_ERR(rbdc)) {
+ ret = PTR_ERR(rbdc);
+ goto done_err;
+ }
rbd_dev->rbd_client = rbdc;
rbd_dev->client = rbdc->client;
return 0;
+done_err:
+ kfree(rbd_opts);
+ return ret;
}
/*
@@ -318,6 +401,7 @@
spin_unlock(&node_lock);
ceph_destroy_client(rbdc->client);
+ kfree(rbdc->rbd_opts);
kfree(rbdc);
}
@@ -666,7 +750,9 @@
struct ceph_osd_req_op *ops,
int num_reply,
void (*rbd_cb)(struct ceph_osd_request *req,
- struct ceph_msg *msg))
+ struct ceph_msg *msg),
+ struct ceph_osd_request **linger_req,
+ u64 *ver)
{
struct ceph_osd_request *req;
struct ceph_file_layout *layout;
@@ -729,12 +815,20 @@
req->r_oid, req->r_oid_len);
up_read(&header->snap_rwsem);
+ if (linger_req) {
+ ceph_osdc_set_request_linger(&dev->client->osdc, req);
+ *linger_req = req;
+ }
+
ret = ceph_osdc_start_request(&dev->client->osdc, req, false);
if (ret < 0)
goto done_err;
if (!rbd_cb) {
ret = ceph_osdc_wait_request(&dev->client->osdc, req);
+ if (ver)
+ *ver = le64_to_cpu(req->r_reassert_version.version);
+ dout("reassert_ver=%lld\n", le64_to_cpu(req->r_reassert_version.version));
ceph_osdc_put_request(req);
}
return ret;
@@ -789,6 +883,11 @@
kfree(req_data);
}
+static void rbd_simple_req_cb(struct ceph_osd_request *req, struct ceph_msg *msg)
+{
+ ceph_osdc_put_request(req);
+}
+
/*
* Do a synchronous ceph osd operation
*/
@@ -801,7 +900,9 @@
int num_reply,
const char *obj,
u64 ofs, u64 len,
- char *buf)
+ char *buf,
+ struct ceph_osd_request **linger_req,
+ u64 *ver)
{
int ret;
struct page **pages;
@@ -833,7 +934,8 @@
flags,
ops,
2,
- NULL);
+ NULL,
+ linger_req, ver);
if (ret < 0)
goto done_ops;
@@ -893,7 +995,7 @@
flags,
ops,
num_reply,
- rbd_req_cb);
+ rbd_req_cb, 0, NULL);
done:
kfree(seg_name);
return ret;
@@ -940,18 +1042,174 @@
u64 snapid,
const char *obj,
u64 ofs, u64 len,
- char *buf)
+ char *buf,
+ u64 *ver)
{
return rbd_req_sync_op(dev, NULL,
(snapid ? snapid : CEPH_NOSNAP),
CEPH_OSD_OP_READ,
CEPH_OSD_FLAG_READ,
NULL,
- 1, obj, ofs, len, buf);
+ 1, obj, ofs, len, buf, NULL, ver);
}
/*
- * Request sync osd read
+ * Request sync osd watch
+ */
+static int rbd_req_sync_notify_ack(struct rbd_device *dev,
+ u64 ver,
+ u64 notify_id,
+ const char *obj)
+{
+ struct ceph_osd_req_op *ops;
+ struct page **pages = NULL;
+ int ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_NOTIFY_ACK, 0);
+ if (ret < 0)
+ return ret;
+
+ ops[0].watch.ver = cpu_to_le64(dev->header.obj_version);
+ ops[0].watch.cookie = notify_id;
+ ops[0].watch.flag = 0;
+
+ ret = rbd_do_request(NULL, dev, NULL, CEPH_NOSNAP,
+ obj, 0, 0, NULL,
+ pages, 0,
+ CEPH_OSD_FLAG_READ,
+ ops,
+ 1,
+ rbd_simple_req_cb, 0, NULL);
+
+ rbd_destroy_ops(ops);
+ return ret;
+}
+
+static void rbd_watch_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
+{
+ struct rbd_device *dev = (struct rbd_device *)data;
+ if (!dev)
+ return;
+
+ dout("rbd_watch_cb %s notify_id=%lld opcode=%d\n", dev->obj_md_name,
+ notify_id, (int)opcode);
+ mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+ __rbd_update_snaps(dev);
+ mutex_unlock(&ctl_mutex);
+
+ rbd_req_sync_notify_ack(dev, ver, notify_id, dev->obj_md_name);
+}
+
+/*
+ * Request sync osd watch
+ */
+static int rbd_req_sync_watch(struct rbd_device *dev,
+ const char *obj,
+ u64 ver)
+{
+ struct ceph_osd_req_op *ops;
+ struct ceph_osd_client *osdc = &dev->client->osdc;
+
+ int ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_WATCH, 0);
+ if (ret < 0)
+ return ret;
+
+ ret = ceph_osdc_create_event(osdc, rbd_watch_cb, 0,
+ (void *)dev, &dev->watch_event);
+ if (ret < 0)
+ goto fail;
+
+ ops[0].watch.ver = cpu_to_le64(ver);
+ ops[0].watch.cookie = cpu_to_le64(dev->watch_event->cookie);
+ ops[0].watch.flag = 1;
+
+ ret = rbd_req_sync_op(dev, NULL,
+ CEPH_NOSNAP,
+ 0,
+ CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
+ ops,
+ 1, obj, 0, 0, NULL,
+ &dev->watch_request, NULL);
+
+ if (ret < 0)
+ goto fail_event;
+
+ rbd_destroy_ops(ops);
+ return 0;
+
+fail_event:
+ ceph_osdc_cancel_event(dev->watch_event);
+ dev->watch_event = NULL;
+fail:
+ rbd_destroy_ops(ops);
+ return ret;
+}
+
+struct rbd_notify_info {
+ struct rbd_device *dev;
+};
+
+static void rbd_notify_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
+{
+ struct rbd_device *dev = (struct rbd_device *)data;
+ if (!dev)
+ return;
+
+ dout("rbd_notify_cb %s notify_id=%lld opcode=%d\n", dev->obj_md_name,
+ notify_id, (int)opcode);
+}
+
+/*
+ * Request sync osd notify
+ */
+static int rbd_req_sync_notify(struct rbd_device *dev,
+ const char *obj)
+{
+ struct ceph_osd_req_op *ops;
+ struct ceph_osd_client *osdc = &dev->client->osdc;
+ struct ceph_osd_event *event;
+ struct rbd_notify_info info;
+ int payload_len = sizeof(u32) + sizeof(u32);
+ int ret;
+
+ ret = rbd_create_rw_ops(&ops, 1, CEPH_OSD_OP_NOTIFY, payload_len);
+ if (ret < 0)
+ return ret;
+
+ info.dev = dev;
+
+ ret = ceph_osdc_create_event(osdc, rbd_notify_cb, 1,
+ (void *)&info, &event);
+ if (ret < 0)
+ goto fail;
+
+ ops[0].watch.ver = 1;
+ ops[0].watch.flag = 1;
+ ops[0].watch.cookie = event->cookie;
+ ops[0].watch.prot_ver = RADOS_NOTIFY_VER;
+ ops[0].watch.timeout = 12;
+
+ ret = rbd_req_sync_op(dev, NULL,
+ CEPH_NOSNAP,
+ 0,
+ CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
+ ops,
+ 1, obj, 0, 0, NULL, NULL, NULL);
+ if (ret < 0)
+ goto fail_event;
+
+ ret = ceph_osdc_wait_event(event, CEPH_OSD_TIMEOUT_DEFAULT);
+ dout("ceph_osdc_wait_event returned %d\n", ret);
+ rbd_destroy_ops(ops);
+ return 0;
+
+fail_event:
+ ceph_osdc_cancel_event(event);
+fail:
+ rbd_destroy_ops(ops);
+ return ret;
+}
+
+/*
+ * Request sync osd rollback
*/
static int rbd_req_sync_rollback_obj(struct rbd_device *dev,
u64 snapid,
@@ -969,13 +1227,10 @@
0,
CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
ops,
- 1, obj, 0, 0, NULL);
+ 1, obj, 0, 0, NULL, NULL, NULL);
rbd_destroy_ops(ops);
- if (ret < 0)
- return ret;
-
return ret;
}
@@ -987,7 +1242,8 @@
const char *cls,
const char *method,
const char *data,
- int len)
+ int len,
+ u64 *ver)
{
struct ceph_osd_req_op *ops;
int cls_len = strlen(cls);
@@ -1010,7 +1266,7 @@
0,
CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
ops,
- 1, obj, 0, 0, NULL);
+ 1, obj, 0, 0, NULL, NULL, ver);
rbd_destroy_ops(ops);
@@ -1156,6 +1412,7 @@
struct rbd_image_header_ondisk *dh;
int snap_count = 0;
u64 snap_names_len = 0;
+ u64 ver;
while (1) {
int len = sizeof(*dh) +
@@ -1171,7 +1428,7 @@
NULL, CEPH_NOSNAP,
rbd_dev->obj_md_name,
0, len,
- (char *)dh);
+ (char *)dh, &ver);
if (rc < 0)
goto out_dh;
@@ -1188,6 +1445,7 @@
}
break;
}
+ header->obj_version = ver;
out_dh:
kfree(dh);
@@ -1205,6 +1463,7 @@
u64 new_snapid;
int ret;
void *data, *data_start, *data_end;
+ u64 ver;
/* we should create a snapshot only if we're pointing at the head */
if (dev->cur_snap)
@@ -1227,7 +1486,7 @@
ceph_encode_64_safe(&data, data_end, new_snapid, bad);
ret = rbd_req_sync_exec(dev, dev->obj_md_name, "rbd", "snap_add",
- data_start, data - data_start);
+ data_start, data - data_start, &ver);
kfree(data_start);
@@ -1259,6 +1518,7 @@
int ret;
struct rbd_image_header h;
u64 snap_seq;
+ int follow_seq = 0;
ret = rbd_read_header(rbd_dev, &h);
if (ret < 0)
@@ -1267,6 +1527,11 @@
down_write(&rbd_dev->header.snap_rwsem);
snap_seq = rbd_dev->header.snapc->seq;
+ if (rbd_dev->header.total_snaps &&
+ rbd_dev->header.snapc->snaps[0] == snap_seq)
+ /* pointing at the head, will need to follow that
+ if head moves */
+ follow_seq = 1;
kfree(rbd_dev->header.snapc);
kfree(rbd_dev->header.snap_names);
@@ -1277,7 +1542,10 @@
rbd_dev->header.snap_names = h.snap_names;
rbd_dev->header.snap_names_len = h.snap_names_len;
rbd_dev->header.snap_sizes = h.snap_sizes;
- rbd_dev->header.snapc->seq = snap_seq;
+ if (follow_seq)
+ rbd_dev->header.snapc->seq = rbd_dev->header.snapc->snaps[0];
+ else
+ rbd_dev->header.snapc->seq = snap_seq;
ret = __rbd_init_snaps_header(rbd_dev);
@@ -1699,7 +1967,28 @@
device_unregister(&rbd_dev->dev);
}
-static ssize_t rbd_add(struct bus_type *bus, const char *buf, size_t count)
+static int rbd_init_watch_dev(struct rbd_device *rbd_dev)
+{
+ int ret, rc;
+
+ do {
+ ret = rbd_req_sync_watch(rbd_dev, rbd_dev->obj_md_name,
+ rbd_dev->header.obj_version);
+ if (ret == -ERANGE) {
+ mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
+ rc = __rbd_update_snaps(rbd_dev);
+ mutex_unlock(&ctl_mutex);
+ if (rc < 0)
+ return rc;
+ }
+ } while (ret == -ERANGE);
+
+ return ret;
+}
+
+static ssize_t rbd_add(struct bus_type *bus,
+ const char *buf,
+ size_t count)
{
struct ceph_osd_client *osdc;
struct rbd_device *rbd_dev;
@@ -1797,6 +2086,10 @@
if (rc)
goto err_out_bus;
+ rc = rbd_init_watch_dev(rbd_dev);
+ if (rc)
+ goto err_out_bus;
+
return count;
err_out_bus:
@@ -1849,6 +2142,12 @@
struct rbd_device *rbd_dev =
container_of(dev, struct rbd_device, dev);
+ if (rbd_dev->watch_request)
+ ceph_osdc_unregister_linger_request(&rbd_dev->client->osdc,
+ rbd_dev->watch_request);
+ if (rbd_dev->watch_event)
+ ceph_osdc_cancel_event(rbd_dev->watch_event);
+
rbd_put_client(rbd_dev);
/* clean up and free blkdev */
@@ -1914,14 +2213,24 @@
ret = rbd_header_add_snap(rbd_dev,
name, GFP_KERNEL);
if (ret < 0)
- goto done_unlock;
+ goto err_unlock;
ret = __rbd_update_snaps(rbd_dev);
if (ret < 0)
- goto done_unlock;
+ goto err_unlock;
+
+ /* shouldn't hold ctl_mutex when notifying.. notify might
+ trigger a watch callback that would need to get that mutex */
+ mutex_unlock(&ctl_mutex);
+
+ /* make a best effort, don't error if failed */
+ rbd_req_sync_notify(rbd_dev, rbd_dev->obj_md_name);
ret = count;
-done_unlock:
+ kfree(name);
+ return ret;
+
+err_unlock:
mutex_unlock(&ctl_mutex);
kfree(name);
return ret;