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rbd: introduce a per-device ordered workqueue
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This is going to be used for re-registering watch requests and
exclusive-lock tasks: acquire/request lock, notify-acquired, release
lock, notify-released.  Some refactoring in the map/unmap paths was
necessary to give this workqueue a meaningful name: "rbdX-tasks".

Signed-off-by: Ilya Dryomov <[email protected]>
Reviewed-by: Mike Christie <[email protected]>
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@idryomov
idryomov committed Aug 24, 2016
1 parent 033268a commit 1643dfa
Showing 1 changed file with 71 additions and 80 deletions.
151 changes: 71 additions & 80 deletions drivers/block/rbd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -128,11 +128,8 @@ static int atomic_dec_return_safe(atomic_t *v)
/*
* An RBD device name will be "rbd#", where the "rbd" comes from
* RBD_DRV_NAME above, and # is a unique integer identifier.
* MAX_INT_FORMAT_WIDTH is used in ensuring DEV_NAME_LEN is big
* enough to hold all possible device names.
*/
#define DEV_NAME_LEN 32
#define MAX_INT_FORMAT_WIDTH ((5 * sizeof (int)) / 2 + 1)

/*
* block device image metadata (in-memory version)
Expand Down Expand Up @@ -353,10 +350,12 @@ struct rbd_device {
struct ceph_object_id header_oid;
struct ceph_object_locator header_oloc;

struct ceph_file_layout layout;
struct ceph_file_layout layout; /* used for all rbd requests */

struct ceph_osd_linger_request *watch_handle;

struct workqueue_struct *task_wq;

struct rbd_spec *parent_spec;
u64 parent_overlap;
atomic_t parent_ref;
Expand Down Expand Up @@ -3944,18 +3943,28 @@ static void rbd_spec_free(struct kref *kref)
kfree(spec);
}

static void rbd_dev_release(struct device *dev)
static void rbd_dev_free(struct rbd_device *rbd_dev)
{
struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
bool need_put = !!rbd_dev->opts;

ceph_oid_destroy(&rbd_dev->header_oid);
ceph_oloc_destroy(&rbd_dev->header_oloc);

rbd_put_client(rbd_dev->rbd_client);
rbd_spec_put(rbd_dev->spec);
kfree(rbd_dev->opts);
kfree(rbd_dev);
}

static void rbd_dev_release(struct device *dev)
{
struct rbd_device *rbd_dev = dev_to_rbd_dev(dev);
bool need_put = !!rbd_dev->opts;

if (need_put) {
destroy_workqueue(rbd_dev->task_wq);
ida_simple_remove(&rbd_dev_id_ida, rbd_dev->dev_id);
}

rbd_dev_free(rbd_dev);

/*
* This is racy, but way better than putting module outside of
Expand All @@ -3966,19 +3975,16 @@ static void rbd_dev_release(struct device *dev)
module_put(THIS_MODULE);
}

static struct rbd_device *rbd_dev_create(struct rbd_client *rbdc,
struct rbd_spec *spec,
struct rbd_options *opts)
static struct rbd_device *__rbd_dev_create(struct rbd_client *rbdc,
struct rbd_spec *spec)
{
struct rbd_device *rbd_dev;

rbd_dev = kzalloc(sizeof (*rbd_dev), GFP_KERNEL);
rbd_dev = kzalloc(sizeof(*rbd_dev), GFP_KERNEL);
if (!rbd_dev)
return NULL;

spin_lock_init(&rbd_dev->lock);
rbd_dev->flags = 0;
atomic_set(&rbd_dev->parent_ref, 0);
INIT_LIST_HEAD(&rbd_dev->node);
init_rwsem(&rbd_dev->header_rwsem);

Expand All @@ -3992,25 +3998,55 @@ static struct rbd_device *rbd_dev_create(struct rbd_client *rbdc,

rbd_dev->rbd_client = rbdc;
rbd_dev->spec = spec;
rbd_dev->opts = opts;

/* Initialize the layout used for all rbd requests */

rbd_dev->layout.stripe_unit = 1 << RBD_MAX_OBJ_ORDER;
rbd_dev->layout.stripe_count = 1;
rbd_dev->layout.object_size = 1 << RBD_MAX_OBJ_ORDER;
rbd_dev->layout.pool_id = spec->pool_id;
RCU_INIT_POINTER(rbd_dev->layout.pool_ns, NULL);

/*
* If this is a mapping rbd_dev (as opposed to a parent one),
* pin our module. We have a ref from do_rbd_add(), so use
* __module_get().
*/
if (rbd_dev->opts)
__module_get(THIS_MODULE);
return rbd_dev;
}

/*
* Create a mapping rbd_dev.
*/
static struct rbd_device *rbd_dev_create(struct rbd_client *rbdc,
struct rbd_spec *spec,
struct rbd_options *opts)
{
struct rbd_device *rbd_dev;

rbd_dev = __rbd_dev_create(rbdc, spec);
if (!rbd_dev)
return NULL;

rbd_dev->opts = opts;

/* get an id and fill in device name */
rbd_dev->dev_id = ida_simple_get(&rbd_dev_id_ida, 0,
minor_to_rbd_dev_id(1 << MINORBITS),
GFP_KERNEL);
if (rbd_dev->dev_id < 0)
goto fail_rbd_dev;

sprintf(rbd_dev->name, RBD_DRV_NAME "%d", rbd_dev->dev_id);
rbd_dev->task_wq = alloc_ordered_workqueue("%s-tasks", WQ_MEM_RECLAIM,
rbd_dev->name);
if (!rbd_dev->task_wq)
goto fail_dev_id;

/* we have a ref from do_rbd_add() */
__module_get(THIS_MODULE);

dout("%s rbd_dev %p dev_id %d\n", __func__, rbd_dev, rbd_dev->dev_id);
return rbd_dev;

fail_dev_id:
ida_simple_remove(&rbd_dev_id_ida, rbd_dev->dev_id);
fail_rbd_dev:
rbd_dev_free(rbd_dev);
return NULL;
}

static void rbd_dev_destroy(struct rbd_device *rbd_dev)
Expand Down Expand Up @@ -4645,46 +4681,6 @@ static int rbd_dev_header_info(struct rbd_device *rbd_dev)
return rbd_dev_v2_header_info(rbd_dev);
}

/*
* Get a unique rbd identifier for the given new rbd_dev, and add
* the rbd_dev to the global list.
*/
static int rbd_dev_id_get(struct rbd_device *rbd_dev)
{
int new_dev_id;

new_dev_id = ida_simple_get(&rbd_dev_id_ida,
0, minor_to_rbd_dev_id(1 << MINORBITS),
GFP_KERNEL);
if (new_dev_id < 0)
return new_dev_id;

rbd_dev->dev_id = new_dev_id;

spin_lock(&rbd_dev_list_lock);
list_add_tail(&rbd_dev->node, &rbd_dev_list);
spin_unlock(&rbd_dev_list_lock);

dout("rbd_dev %p given dev id %d\n", rbd_dev, rbd_dev->dev_id);

return 0;
}

/*
* Remove an rbd_dev from the global list, and record that its
* identifier is no longer in use.
*/
static void rbd_dev_id_put(struct rbd_device *rbd_dev)
{
spin_lock(&rbd_dev_list_lock);
list_del_init(&rbd_dev->node);
spin_unlock(&rbd_dev_list_lock);

ida_simple_remove(&rbd_dev_id_ida, rbd_dev->dev_id);

dout("rbd_dev %p released dev id %d\n", rbd_dev, rbd_dev->dev_id);
}

/*
* Skips over white space at *buf, and updates *buf to point to the
* first found non-space character (if any). Returns the length of
Expand Down Expand Up @@ -5077,8 +5073,7 @@ static int rbd_dev_probe_parent(struct rbd_device *rbd_dev, int depth)
goto out_err;
}

parent = rbd_dev_create(rbd_dev->rbd_client, rbd_dev->parent_spec,
NULL);
parent = __rbd_dev_create(rbd_dev->rbd_client, rbd_dev->parent_spec);
if (!parent) {
ret = -ENOMEM;
goto out_err;
Expand Down Expand Up @@ -5113,22 +5108,12 @@ static int rbd_dev_device_setup(struct rbd_device *rbd_dev)
{
int ret;

/* Get an id and fill in device name. */

ret = rbd_dev_id_get(rbd_dev);
if (ret)
goto err_out_unlock;

BUILD_BUG_ON(DEV_NAME_LEN
< sizeof (RBD_DRV_NAME) + MAX_INT_FORMAT_WIDTH);
sprintf(rbd_dev->name, "%s%d", RBD_DRV_NAME, rbd_dev->dev_id);

/* Record our major and minor device numbers. */

if (!single_major) {
ret = register_blkdev(0, rbd_dev->name);
if (ret < 0)
goto err_out_id;
goto err_out_unlock;

rbd_dev->major = ret;
rbd_dev->minor = 0;
Expand Down Expand Up @@ -5160,6 +5145,10 @@ static int rbd_dev_device_setup(struct rbd_device *rbd_dev)
set_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags);
up_write(&rbd_dev->header_rwsem);

spin_lock(&rbd_dev_list_lock);
list_add_tail(&rbd_dev->node, &rbd_dev_list);
spin_unlock(&rbd_dev_list_lock);

add_disk(rbd_dev->disk);
pr_info("%s: added with size 0x%llx\n", rbd_dev->disk->disk_name,
(unsigned long long) rbd_dev->mapping.size);
Expand All @@ -5173,8 +5162,6 @@ static int rbd_dev_device_setup(struct rbd_device *rbd_dev)
err_out_blkdev:
if (!single_major)
unregister_blkdev(rbd_dev->major, rbd_dev->name);
err_out_id:
rbd_dev_id_put(rbd_dev);
err_out_unlock:
up_write(&rbd_dev->header_rwsem);
return ret;
Expand Down Expand Up @@ -5406,12 +5393,16 @@ static ssize_t rbd_add_single_major(struct bus_type *bus,
static void rbd_dev_device_release(struct rbd_device *rbd_dev)
{
rbd_free_disk(rbd_dev);

spin_lock(&rbd_dev_list_lock);
list_del_init(&rbd_dev->node);
spin_unlock(&rbd_dev_list_lock);

clear_bit(RBD_DEV_FLAG_EXISTS, &rbd_dev->flags);
device_del(&rbd_dev->dev);
rbd_dev_mapping_clear(rbd_dev);
if (!single_major)
unregister_blkdev(rbd_dev->major, rbd_dev->name);
rbd_dev_id_put(rbd_dev);
}

static void rbd_dev_remove_parent(struct rbd_device *rbd_dev)
Expand Down

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