On 4/19/19 6:05 PM, Coly Li wrote:
If a bcache device is in dirty state and its cache set is not
registered, this bcache deivce will not appear in /dev/bcache<N>,
and there is no way to stop it or remove the bcache kernel module.
This is an as-designed behavior, but sometimes people has to reboot
whole system to release or stop the pending backing device.
This sysfs interface may remove such pending bcache devices when
write anything into the sysfs file manually.
Signed-off-by: Coly Li <colyli@xxxxxxx>
---
drivers/md/bcache/super.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 55 insertions(+)
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 9b41e0b62cc0..e988e46a6479 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -2246,9 +2246,13 @@ static int register_cache(struct cache_sb *sb, struct page *sb_page,
static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
const char *buffer, size_t size);
+static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
+ struct kobj_attribute *attr,
+ const char *buffer, size_t size);
kobj_attribute_write(register, register_bcache);
kobj_attribute_write(register_quiet, register_bcache);
+kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
static bool bch_is_open_backing(struct block_device *bdev)
{
@@ -2373,6 +2377,56 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
goto out;
}
+
+struct pdev {
+ struct list_head list;
+ struct cached_dev *dc;
+};
+
+static ssize_t bch_pending_bdevs_cleanup(struct kobject *k,
+ struct kobj_attribute *attr,
+ const char *buffer,
+ size_t size)
+{
+ LIST_HEAD(pending_devs);
+ ssize_t ret = size;
+ struct cached_dev *dc, *tdc;
+ struct pdev *pdev, *tpdev;
+ struct cache_set *c, *tc;
+
+ mutex_lock(&bch_register_lock);
+ list_for_each_entry_safe(dc, tdc, &uncached_devices, list) {
+ pdev = kmalloc(sizeof(struct pdev), GFP_KERNEL);
+ if (!pdev)
+ break;
+ pdev->dc = dc;
+ list_add(&pdev->list, &pending_devs);
+ }
+
+ list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
+ list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
+ char *pdev_set_uuid = pdev->dc->sb.set_uuid;
+ char *set_uuid = c->sb.uuid;
+
+ if (!memcmp(pdev_set_uuid, set_uuid, 16)) {
+ list_del(&pdev->list);
+ kfree(pdev);
+ break;
+ }
+ }
+ }
+ mutex_unlock(&bch_register_lock);
+
+ list_for_each_entry_safe(pdev, tpdev, &pending_devs, list) {
+ pr_info("delete pdev %p", pdev);
+ list_del(&pdev->list);
+ bcache_device_stop(&pdev->dc->disk);
+ kfree(pdev);
+ }
+
+ return ret;
+}
+
static int bcache_reboot(struct notifier_block *n, unsigned long code, void *x)
{
if (code == SYS_DOWN ||
@@ -2483,6 +2537,7 @@ static int __init bcache_init(void)
static const struct attribute *files[] = {
&ksysfs_register.attr,
&ksysfs_register_quiet.attr,
+ &ksysfs_pendings_cleanup.attr,
NULL
};
_Actually_ I would like it better if the bcache device would be present
in sysfs for these cases, too, albeit in a disabled state.
That would allow us to remove the device like normal and we wouldn't
need to worry about yet another interface.
Cheers,
Hannes
--
Dr. Hannes Reinecke Teamlead Storage & Networking
hare@xxxxxxx +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
HRB 21284 (AG Nürnberg)
