[PATCH RFC v2 05/14] md: delay registeration of bitmap_ops until creating bitmap
From: Yu Kuai
Date: Fri Mar 28 2025 - 02:17:21 EST
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 | 84 ++++++++++++++++++++++++++++++++-----------------
1 file changed, 55 insertions(+), 29 deletions(-)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 6ec8b5311a0a..c1f13288069a 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -651,32 +651,47 @@ static void no_op(struct percpu_ref *r) {}
static void 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;
+
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;
+ }
+
+ 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));
}
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;
- mddev_set_bitmap_ops(mddev);
-
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;
}
@@ -714,7 +729,6 @@ 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);
}
@@ -6046,11 +6060,6 @@ 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");
@@ -6126,6 +6135,25 @@ static void md_safemode_timeout(struct timer_list *t)
static int start_dirty_degraded;
+static int md_bitmap_create(struct mddev *mddev)
+{
+ if (!md_bitmap_registered(mddev))
+ mddev_set_bitmap_ops(mddev);
+ if (!mddev->bitmap_ops)
+ return -ENOENT;
+
+ return mddev->bitmap_ops->create(mddev);
+}
+
+static void md_bitmap_destroy(struct mddev *mddev)
+{
+ if (!md_bitmap_registered(mddev))
+ return;
+
+ mddev->bitmap_ops->destroy(mddev);
+ mddev_clear_bitmap_ops(mddev);
+}
+
int md_run(struct mddev *mddev)
{
int err;
@@ -6290,9 +6318,9 @@ int md_run(struct mddev *mddev)
(unsigned long long)pers->size(mddev, 0, 0) / 2);
err = -EINVAL;
}
- if (err == 0 && pers->sync_request && md_bitmap_registered(mddev) &&
+ if (err == 0 && pers->sync_request &&
(mddev->bitmap_info.file || mddev->bitmap_info.offset)) {
- err = mddev->bitmap_ops->create(mddev);
+ err = md_bitmap_create(mddev);
if (err)
pr_warn("%s: failed to create bitmap (%d)\n",
mdname(mddev), err);
@@ -6365,8 +6393,7 @@ int md_run(struct mddev *mddev)
pers->free(mddev, mddev->private);
mddev->private = NULL;
put_pers(pers);
- if (md_bitmap_registered(mddev))
- mddev->bitmap_ops->destroy(mddev);
+ md_bitmap_destroy(mddev);
abort:
bioset_exit(&mddev->io_clone_set);
exit_sync_set:
@@ -6389,7 +6416,7 @@ int do_md_run(struct mddev *mddev)
if (md_bitmap_registered(mddev)) {
err = mddev->bitmap_ops->load(mddev);
if (err) {
- mddev->bitmap_ops->destroy(mddev);
+ md_bitmap_destroy(mddev);
goto out;
}
}
@@ -6580,8 +6607,7 @@ static void __md_stop(struct mddev *mddev)
{
struct md_personality *pers = mddev->pers;
- if (md_bitmap_registered(mddev))
- mddev->bitmap_ops->destroy(mddev);
+ md_bitmap_destroy(mddev);
mddev_detach(mddev);
spin_lock(&mddev->lock);
mddev->pers = NULL;
@@ -7361,16 +7387,16 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
err = 0;
if (mddev->pers) {
if (fd >= 0) {
- err = mddev->bitmap_ops->create(mddev);
+ err = md_bitmap_create(mddev);
if (!err)
err = mddev->bitmap_ops->load(mddev);
if (err) {
- mddev->bitmap_ops->destroy(mddev);
+ md_bitmap_destroy(mddev);
fd = -1;
}
} else if (fd < 0) {
- mddev->bitmap_ops->destroy(mddev);
+ md_bitmap_destroy(mddev);
}
}
@@ -7685,12 +7711,12 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
mddev->bitmap_info.default_offset;
mddev->bitmap_info.space =
mddev->bitmap_info.default_space;
- rv = mddev->bitmap_ops->create(mddev);
+ rv = md_bitmap_create(mddev);
if (!rv)
rv = mddev->bitmap_ops->load(mddev);
if (rv)
- mddev->bitmap_ops->destroy(mddev);
+ md_bitmap_destroy(mddev);
} else {
struct md_bitmap_stats stats;
@@ -7716,7 +7742,7 @@ static int update_array_info(struct mddev *mddev, mdu_array_info_t *info)
put_cluster_ops(mddev);
mddev->safemode_delay = DEFAULT_SAFEMODE_DELAY;
}
- mddev->bitmap_ops->destroy(mddev);
+ md_bitmap_destroy(mddev);
mddev->bitmap_info.offset = 0;
}
}
--
2.39.2