[ 154/171] rbd: kill create_snap sysfs entry

Greg Kroah-Hartman
2013-01-15T22:53:53Z

From: Alex Elder <elder@inktank.com>

Josh proposed the following change, and I don't think I could
explain it any better than he did:

From: Josh Durgin <josh.durgin@inktank.com>
Date: Tue, 24 Jul 2012 14:22:11 -0700
To: ceph-devel <ceph-devel@vger.kernel.org>
Message-ID: <500F1203.9050605@inktank.com>
From: Josh Durgin <josh.durgin@inktank.com>

Right now the kernel still has one piece of rbd management
duplicated from the rbd command line tool: snapshot creation.
There's nothing special about snapshot creation that makes it
advantageous to do from the kernel, so I'd like to remove the
create_snap sysfs interface. That is,
/sys/bus/rbd/devices/<id>/create_snap
would be removed.

Does anyone rely on the sysfs interface for creating rbd
snapshots? If so, how hard would it be to replace with:

rbd snap create pool/image@snap

Is there any benefit to the sysfs interface that I'm missing?

Josh

This patch implements this proposal, removing the code that
implements the "snap_create" sysfs interface for rbd images.
As a result, quite a lot of other supporting code goes away.

[elder@inktank.com: commented out rbd_req_sync_exec() to avoid warning]

Suggested-by: Josh Durgin <josh.durgin@inktank.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
(based on commit 02cdb02ceab1f3dd9ac2bc899fc51f0e0e744782)
---
Documentation/ABI/testing/sysfs-bus-rbd | 6 -
drivers/block/rbd.c | 165 --------------------------------
2 files changed, 2 insertions(+), 169 deletions(-)

--- a/Documentation/ABI/testing/sysfs-bus-rbd
+++ b/Documentation/ABI/testing/sysfs-bus-rbd
@@ -51,12 +51,6 @@ current_snap

The current snapshot for which the device is mapped.

-create_snap
-
- Create a snapshot:
-
- $ echo <snap-name> > /sys/bus/rbd/devices/<dev-id>/snap_create
-
snap_*

A directory per each snapshot
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -201,10 +201,6 @@ static DEFINE_SPINLOCK(rbd_client_list_l

static int __rbd_init_snaps_header(struct rbd_device *rbd_dev);
static void rbd_dev_release(struct device *dev);
-static ssize_t rbd_snap_add(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count);
static void __rbd_remove_snap_dev(struct rbd_device *rbd_dev,
struct rbd_snap *snap);

@@ -1307,71 +1303,7 @@ static int rbd_req_sync_unwatch(struct r
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->rbd_client->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;
-}
-
+#if 0
/*
* Request sync osd read
*/
@@ -1411,6 +1343,7 @@ static int rbd_req_sync_exec(struct rbd_
dout("cls_exec returned %d\n", ret);
return ret;
}
+#endif

static struct rbd_req_coll *rbd_alloc_coll(int num_reqs)
{
@@ -1645,57 +1578,6 @@ out_dh:
return rc;
}

-/*
- * create a snapshot
- */
-static int rbd_header_add_snap(struct rbd_device *dev,
- const char *snap_name,
- gfp_t gfp_flags)
-{
- int name_len = strlen(snap_name);
- u64 new_snapid;
- int ret;
- void *data, *p, *e;
- u64 ver;
- struct ceph_mon_client *monc;
-
- /* we should create a snapshot only if we're pointing at the head */
- if (dev->snap_id != CEPH_NOSNAP)
- return -EINVAL;
-
- monc = &dev->rbd_client->client->monc;
- ret = ceph_monc_create_snapid(monc, dev->poolid, &new_snapid);
- dout("created snapid=%lld\n", new_snapid);
- if (ret < 0)
- return ret;
-
- data = kmalloc(name_len + 16, gfp_flags);
- if (!data)
- return -ENOMEM;
-
- p = data;
- e = data + name_len + 16;
-
- ceph_encode_string_safe(&p, e, snap_name, name_len, bad);
- ceph_encode_64_safe(&p, e, new_snapid, bad);
-
- ret = rbd_req_sync_exec(dev, dev->obj_md_name, "rbd", "snap_add",
- data, p - data, &ver);
-
- kfree(data);
-
- if (ret < 0)
- return ret;
-
- down_write(&dev->header_rwsem);
- dev->header.snapc->seq = new_snapid;
- up_write(&dev->header_rwsem);
-
- return 0;
-bad:
- return -ERANGE;
-}
-
static void __rbd_remove_all_snaps(struct rbd_device *rbd_dev)
{
struct rbd_snap *snap;
@@ -1923,7 +1805,6 @@ static DEVICE_ATTR(pool, S_IRUGO, rbd_po
static DEVICE_ATTR(name, S_IRUGO, rbd_name_show, NULL);
static DEVICE_ATTR(refresh, S_IWUSR, NULL, rbd_image_refresh);
static DEVICE_ATTR(current_snap, S_IRUGO, rbd_snap_show, NULL);
-static DEVICE_ATTR(create_snap, S_IWUSR, NULL, rbd_snap_add);

static struct attribute *rbd_attrs[] = {
&dev_attr_size.attr,
@@ -1933,7 +1814,6 @@ static struct attribute *rbd_attrs[] = {
&dev_attr_name.attr,
&dev_attr_current_snap.attr,
&dev_attr_refresh.attr,
- &dev_attr_create_snap.attr,
NULL
};

@@ -2563,47 +2443,6 @@ done:
return ret;
}

-static ssize_t rbd_snap_add(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count)
-{
- struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
- int ret;
- char *name = kmalloc(count + 1, GFP_KERNEL);
- if (!name)
- return -ENOMEM;
-
- snprintf(name, count, "%s", buf);
-
- mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);
-
- ret = rbd_header_add_snap(rbd_dev,
- name, GFP_KERNEL);
- if (ret < 0)
- goto err_unlock;
-
- ret = __rbd_update_snaps(rbd_dev);
- if (ret < 0)
- 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;
- kfree(name);
- return ret;
-
-err_unlock:
- mutex_unlock(&ctl_mutex);
- kfree(name);
- return ret;
-}
-
/*
* create control files in sysfs
* /sys/bus/rbd/...