Josh proposed the following change, and I don't think I could
explain it any better than he did:
From: Josh Durgin <josh.durgin@xxxxxxxxxxx>
Date: Tue, 24 Jul 2012 14:22:11 -0700
To: ceph-devel <ceph-devel@xxxxxxxxxxxxxxx>
Message-ID: <500F1203.9050605@xxxxxxxxxxx>
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.
Suggested-by: Josh Durgin <josh.durgin@xxxxxxxxxxx>
Signed-off-by: Alex Elder <elder@xxxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-rbd | 6 --
drivers/block/rbd.c | 158
-------------------------------
2 files changed, 164 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-rbd
b/Documentation/ABI/testing/sysfs-bus-rbd
index 7cbbe34..6fe4224 100644
--- a/Documentation/ABI/testing/sysfs-bus-rbd
+++ b/Documentation/ABI/testing/sysfs-bus-rbd
@@ -62,12 +62,6 @@ 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
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 5a3132e..d73edb1 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -212,10 +212,6 @@ static int rbd_dev_snaps_update(struct rbd_device
*rbd_dev);
static int rbd_dev_snaps_register(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_snap *snap);
static ssize_t rbd_add(struct bus_type *bus, const char *buf,
@@ -1375,71 +1371,6 @@ static int rbd_req_sync_unwatch(struct rbd_device
*rbd_dev)
return ret;
}
-struct rbd_notify_info {
- struct rbd_device *rbd_dev;
-};
-
-static void rbd_notify_cb(u64 ver, u64 notify_id, u8 opcode, void *data)
-{
- struct rbd_device *rbd_dev = (struct rbd_device *)data;
- if (!rbd_dev)
- return;
-
- dout("rbd_notify_cb %s notify_id=%llu opcode=%u\n",
- rbd_dev->header_name, (unsigned long long) notify_id,
- (unsigned int) opcode);
-}
-
-/*
- * Request sync osd notify
- */
-static int rbd_req_sync_notify(struct rbd_device *rbd_dev)
-{
- struct ceph_osd_req_op *ops;
- struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
- struct ceph_osd_event *event;
- struct rbd_notify_info info;
- int payload_len = sizeof(u32) + sizeof(u32);
- int ret;
-
- ops = rbd_create_rw_ops(1, CEPH_OSD_OP_NOTIFY, payload_len);
- if (!ops)
- return -ENOMEM;
-
- info.rbd_dev = rbd_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(rbd_dev, NULL,
- CEPH_NOSNAP,
- CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
- ops,
- rbd_dev->header_name,
- 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;
-}
-
/*
* Synchronous osd object method call
*/
@@ -1761,52 +1692,6 @@ static int rbd_read_header(struct rbd_device
*rbd_dev,
return ret;
}
-/*
- * create a snapshot
- */
-static int rbd_header_add_snap(struct rbd_device *rbd_dev,
- const char *snap_name,
- gfp_t gfp_flags)
-{
- int name_len = strlen(snap_name);
- u64 new_snapid;
- int ret;
- void *data, *p, *e;
- struct ceph_mon_client *monc;
-
- /* we should create a snapshot only if we're pointing at the head */
- if (rbd_dev->mapping.snap_id != CEPH_NOSNAP)
- return -EINVAL;
-
- monc = &rbd_dev->rbd_client->client->monc;
- ret = ceph_monc_create_snapid(monc, rbd_dev->pool_id, &new_snapid);
- dout("created snapid=%llu\n", (unsigned long long) 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(rbd_dev, rbd_dev->header_name,
- "rbd", "snap_add",
- data, (size_t) (p - data), NULL, 0,
- CEPH_OSD_FLAG_WRITE | CEPH_OSD_FLAG_ONDISK,
- NULL);
-
- kfree(data);
-
- return ret < 0 ? ret : 0;
-bad:
- return -ERANGE;
-}
-
static void __rbd_remove_all_snaps(struct rbd_device *rbd_dev)
{
struct rbd_snap *snap;
@@ -2030,7 +1915,6 @@ static DEVICE_ATTR(name, S_IRUGO, rbd_name_show,
NULL);
static DEVICE_ATTR(image_id, S_IRUGO, rbd_image_id_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,
@@ -2042,7 +1926,6 @@ static struct attribute *rbd_attrs[] = {
&dev_attr_image_id.attr,
&dev_attr_current_snap.attr,
&dev_attr_refresh.attr,
- &dev_attr_create_snap.attr,
NULL
};
@@ -2888,47 +2771,6 @@ 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_refresh_header(rbd_dev, NULL);
- 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);
-
- ret = count;
- kfree(name);
- return ret;
-
-err_unlock:
- mutex_unlock(&ctl_mutex);
- kfree(name);
- return ret;
-}
-
/*
* create control files in sysfs
* /sys/bus/rbd/...
