On 5/24/25 08:13, Yu Kuai wrote:
From: Yu Kuai <yukuai3@xxxxxxxxxx>
Currently bitmap_ops is registered while allocating mddev, this is fine
when there is only one bitmap_ops, however, after introduing a new
bitmap_ops, user space need a time window to choose which bitmap_ops to
use while creating new array.
Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
drivers/md/md.c | 86 +++++++++++++++++++++++++++++++------------------
1 file changed, 55 insertions(+), 31 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4eb0c6effd5b..dc4b85f30e13 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -674,39 +674,50 @@ static void no_op(struct percpu_ref *r) {}
static bool mddev_set_bitmap_ops(struct mddev *mddev)
{
+ struct bitmap_operations *old = mddev->bitmap_ops;
+ struct md_submodule_head *head;
+
+ if (mddev->bitmap_id == ID_BITMAP_NONE ||
+ (old && old->head.id == mddev->bitmap_id))
+ return true;
+
xa_lock(&md_submodule);
- mddev->bitmap_ops = xa_load(&md_submodule, mddev->bitmap_id);
+ head = xa_load(&md_submodule, mddev->bitmap_id);
xa_unlock(&md_submodule);
- if (!mddev->bitmap_ops) {
- pr_warn_once("md: can't find bitmap id %d\n", mddev->bitmap_id);
+ if (WARN_ON_ONCE(!head || head->type != MD_BITMAP)) {
+ pr_err("md: can't find bitmap id %d\n", mddev->bitmap_id);
return false;
}
+ if (old && old->group)
+ sysfs_remove_group(&mddev->kobj, old->group);
+
+ mddev->bitmap_ops = (void *)head;
+ if (mddev->bitmap_ops && mddev->bitmap_ops->group &&
+ sysfs_create_group(&mddev->kobj, mddev->bitmap_ops->group))
+ pr_warn("md: cannot register extra bitmap attributes for %s\n",
+ mdname(mddev));
+
return true;
}
static void mddev_clear_bitmap_ops(struct mddev *mddev)
{
+ if (mddev->bitmap_ops && mddev->bitmap_ops->group)
+ sysfs_remove_group(&mddev->kobj, mddev->bitmap_ops->group);
+
mddev->bitmap_ops = NULL;
}
int mddev_init(struct mddev *mddev)
{
- mddev->bitmap_id = ID_BITMAP;
-
- if (!mddev_set_bitmap_ops(mddev))
- return -EINVAL;
-
if (percpu_ref_init(&mddev->active_io, active_io_release,
- PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
- mddev_clear_bitmap_ops(mddev);
+ PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
return -ENOMEM;
- }
if (percpu_ref_init(&mddev->writes_pending, no_op,
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
- mddev_clear_bitmap_ops(mddev);
percpu_ref_exit(&mddev->active_io);
return -ENOMEM;
}
@@ -734,6 +745,7 @@ int mddev_init(struct mddev *mddev)
mddev->resync_min = 0;
mddev->resync_max = MaxSector;
mddev->level = LEVEL_NONE;
+ mddev->bitmap_id = ID_BITMAP;
INIT_WORK(&mddev->sync_work, md_start_sync);
INIT_WORK(&mddev->del_work, mddev_delayed_delete);
@@ -744,7 +756,6 @@ EXPORT_SYMBOL_GPL(mddev_init);
void mddev_destroy(struct mddev *mddev)
{
- mddev_clear_bitmap_ops(mddev);
percpu_ref_exit(&mddev->active_io);
percpu_ref_exit(&mddev->writes_pending);
}
@@ -6093,11 +6104,6 @@ struct mddev *md_alloc(dev_t dev, char *name)
return ERR_PTR(error);
}
- if (md_bitmap_registered(mddev) && mddev->bitmap_ops->group)
- if (sysfs_create_group(&mddev->kobj, mddev->bitmap_ops->group))
- pr_warn("md: cannot register extra bitmap attributes for %s\n",
- mdname(mddev));
-
kobject_uevent(&mddev->kobj, KOBJ_ADD);
mddev->sysfs_state = sysfs_get_dirent_safe(mddev->kobj.sd, "array_state");
mddev->sysfs_level = sysfs_get_dirent_safe(mddev->kobj.sd, "level");
But now you've killed udev event processing.
Once the 'add' event is sent _all_ sysfs attributes must be present,
otherwise you'll have a race condition where udev is checking for
attributes which are present only later.
So when moving things around ensure to move the kobject_uevent() call, too.
(ideally you would set the sysfs attributes when calling 'add_device()',
but not sure if that's possible here.)
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@xxxxxxx +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
