When a new snapshot is found in an rbd device's updated snapshot context, __rbd_add_snap_dev() is called to create and insert an entry in the rbd devices list of snapshots. In addition, a Linux device is registered to represent the snapshot.
For version 2 rbd images, it will be undesirable to initialize the device right away. So in anticipation of that, this patch separates the insertion of a snapshot entry in the snaps list from the creation of devices for those snapshots. To do this, create a new function rbd_dev_snaps_register() which traverses the list of snapshots and calls rbd_register_snap_dev() on any that have not yet been registered. Rename rbd_dev_snap_devs_update() to be rbd_dev_snaps_update() to better reflect that only the entry in the snaps list and not the snapshot's device is affected by the function. For now, call rbd_dev_snaps_register() immediately after each call to rbd_dev_snaps_update(). Signed-off-by: Alex Elder <[email protected]> --- drivers/block/rbd.c | 58 ++++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 46 insertions(+), 12 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 14034e3..d03fb0f 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -204,7 +204,9 @@ static DEFINE_SPINLOCK(rbd_dev_list_lock); static LIST_HEAD(rbd_client_list); /* clients */ static DEFINE_SPINLOCK(rbd_client_list_lock); -static int rbd_dev_snap_devs_update(struct rbd_device *rbd_dev); +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, @@ -648,6 +650,7 @@ static int rbd_header_set_snap(struct rbd_device *rbd_dev, char *snap_name) rbd_dev->mapping.size = rbd_dev->header.image_size; rbd_dev->mapping.snap_exists = false; rbd_dev->mapping.read_only = rbd_dev->rbd_opts.read_only; + ret = 0; } else { ret = snap_by_name(rbd_dev, snap_name); if (ret < 0) @@ -656,8 +659,6 @@ static int rbd_header_set_snap(struct rbd_device *rbd_dev, char *snap_name) rbd_dev->mapping.read_only = true; } rbd_dev->mapping.snap_name = snap_name; - - ret = 0; done: return ret; } @@ -1840,7 +1841,9 @@ static int __rbd_refresh_header(struct rbd_device *rbd_dev, u64 *hver) WARN_ON(strcmp(rbd_dev->header.object_prefix, h.object_prefix)); kfree(h.object_prefix); - ret = rbd_dev_snap_devs_update(rbd_dev); + ret = rbd_dev_snaps_update(rbd_dev); + if (!ret) + ret = rbd_dev_snaps_register(rbd_dev); up_write(&rbd_dev->header_rwsem); @@ -2085,10 +2088,16 @@ static struct device_type rbd_snap_device_type = { .release = rbd_snap_dev_release, }; +static bool rbd_snap_registered(struct rbd_snap *snap) +{ + return snap->dev.type == &rbd_snap_device_type; +} + static void __rbd_remove_snap_dev(struct rbd_snap *snap) { list_del(&snap->node); - device_unregister(&snap->dev); + if (rbd_snap_registered(snap)) + device_unregister(&snap->dev); } static int rbd_register_snap_dev(struct rbd_snap *snap, @@ -2101,6 +2110,8 @@ static int rbd_register_snap_dev(struct rbd_snap *snap, dev->parent = parent; dev->release = rbd_snap_dev_release; dev_set_name(dev, "snap_%s", snap->name); + dout("%s: registering device for snapshot %s\n", __func__, snap->name); + ret = device_register(dev); return ret; @@ -2123,11 +2134,6 @@ static struct rbd_snap *__rbd_add_snap_dev(struct rbd_device *rbd_dev, snap->size = rbd_dev->header.snap_sizes[i]; snap->id = rbd_dev->header.snapc->snaps[i]; - if (device_is_registered(&rbd_dev->dev)) { - ret = rbd_register_snap_dev(snap, &rbd_dev->dev); - if (ret < 0) - goto err; - } return snap; @@ -2150,7 +2156,7 @@ err: * snapshot id, highest id first. (Snapshots in the rbd_dev's list * are also maintained in that order.) */ -static int rbd_dev_snap_devs_update(struct rbd_device *rbd_dev) +static int rbd_dev_snaps_update(struct rbd_device *rbd_dev) { struct ceph_snap_context *snapc = rbd_dev->header.snapc; const u32 snap_count = snapc->num_snaps; @@ -2237,6 +2243,31 @@ static int rbd_dev_snap_devs_update(struct rbd_device *rbd_dev) return 0; } +/* + * Scan the list of snapshots and register the devices for any that + * have not already been registered. + */ +static int rbd_dev_snaps_register(struct rbd_device *rbd_dev) +{ + struct rbd_snap *snap; + int ret = 0; + + dout("%s called\n", __func__); + if (!device_is_registered(&rbd_dev->dev)) + return 0; + + list_for_each_entry(snap, &rbd_dev->snaps, node) { + if (!rbd_snap_registered(snap)) { + ret = rbd_register_snap_dev(snap, &rbd_dev->dev); + if (ret < 0) + break; + } + } + dout("%s: returning %d\n", __func__, ret); + + return ret; +} + static int rbd_bus_add_dev(struct rbd_device *rbd_dev) { struct device *dev; @@ -2587,7 +2618,10 @@ static ssize_t rbd_add(struct bus_type *bus, if (rc) goto err_out_unlock; - rc = rbd_dev_snap_devs_update(rbd_dev); + rc = rbd_dev_snaps_update(rbd_dev); + if (rc) + goto err_out_unlock; + rc = rbd_dev_snaps_register(rbd_dev); if (rc) goto err_out_unlock; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
