bcache: Fix sysfs splat on shutdown with flash only devs

Whoops.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>

6 files changed, 30 insertions, 33 deletions

diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h
index ab0b2150fed6..97ef126b68bb 100644
--- a/drivers/md/bcache/bcache.h
+++ b/drivers/md/bcache/bcache.h
@@ -266,12 +266,10 @@ struct bcache_device {
 
         struct gendisk          *disk;
 
-        /* If nonzero, we're closing */
-        atomic_t                closing;
-
-        /* If nonzero, we're detaching/unregistering from cache set */
-        atomic_t                detaching;
-        int                     flush_done;
+        unsigned long           flags;
+#define BCACHE_DEV_CLOSING      0
+#define BCACHE_DEV_DETACHING    1
+#define BCACHE_DEV_UNLINK_DONE  2
 
         unsigned                nr_stripes;
         unsigned                stripe_size;
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index f645da61189a..9f5a1386f77a 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -512,7 +512,7 @@ static bool check_should_bypass(struct cached_dev *dc, struct bio *bio)
         struct task_struct *task = current;
         struct io *i;
 
-        if (atomic_read(&dc->disk.detaching) ||
+        if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
             c->gc_stats.in_use > CUTOFF_CACHE_ADD ||
             (bio->bi_rw & REQ_DISCARD))
                 goto skip;
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 43fcfe38be11..fa1d53087f88 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -621,7 +621,7 @@ static void prio_read(struct cache *ca, uint64_t bucket)
 static int open_dev(struct block_device *b, fmode_t mode)
 {
         struct bcache_device *d = b->bd_disk->private_data;
-        if (atomic_read(&d->closing))
+        if (test_bit(BCACHE_DEV_CLOSING, &d->flags))
                 return -ENXIO;
 
         closure_get(&d->cl);
@@ -650,20 +650,24 @@ static const struct block_device_operations bcache_ops = {
 
 void bcache_device_stop(struct bcache_device *d)
 {
-        if (!atomic_xchg(&d->closing, 1))
+        if (!test_and_set_bit(BCACHE_DEV_CLOSING, &d->flags))
                 closure_queue(&d->cl);
 }
 
 static void bcache_device_unlink(struct bcache_device *d)
 {
-        unsigned i;
-        struct cache *ca;
+        lockdep_assert_held(&bch_register_lock);
 
-        sysfs_remove_link(&d->c->kobj, d->name);
-        sysfs_remove_link(&d->kobj, "cache");
+        if (d->c && !test_and_set_bit(BCACHE_DEV_UNLINK_DONE, &d->flags)) {
+                unsigned i;
+                struct cache *ca;
 
-        for_each_cache(ca, d->c, i)
-                bd_unlink_disk_holder(ca->bdev, d->disk);
+                sysfs_remove_link(&d->c->kobj, d->name);
+                sysfs_remove_link(&d->kobj, "cache");
+
+                for_each_cache(ca, d->c, i)
+                        bd_unlink_disk_holder(ca->bdev, d->disk);
+        }
 }
 
 static void bcache_device_link(struct bcache_device *d, struct cache_set *c,
@@ -687,19 +691,16 @@ static void bcache_device_detach(struct bcache_device *d)
 {
         lockdep_assert_held(&bch_register_lock);
 
-        if (atomic_read(&d->detaching)) {
+        if (test_bit(BCACHE_DEV_DETACHING, &d->flags)) {
                 struct uuid_entry *u = d->c->uuids + d->id;
 
                 SET_UUID_FLASH_ONLY(u, 0);
                 memcpy(u->uuid, invalid_uuid, 16);
                 u->invalidated = cpu_to_le32(get_seconds());
                 bch_uuid_write(d->c);
-
-                atomic_set(&d->detaching, 0);
         }
 
-        if (!d->flush_done)
-                bcache_device_unlink(d);
+        bcache_device_unlink(d);
 
         d->c->devices[d->id] = NULL;
         closure_put(&d->c->caching);
@@ -879,7 +880,7 @@ static void cached_dev_detach_finish(struct work_struct *w)
         struct closure cl;
         closure_init_stack(&cl);
 
-        BUG_ON(!atomic_read(&dc->disk.detaching));
+        BUG_ON(!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags));
         BUG_ON(atomic_read(&dc->count));
 
         mutex_lock(&bch_register_lock);
@@ -893,6 +894,8 @@ static void cached_dev_detach_finish(struct work_struct *w)
         bcache_device_detach(&dc->disk);
         list_move(&dc->list, &uncached_devices);
 
+        clear_bit(BCACHE_DEV_DETACHING, &dc->disk.flags);
+
         mutex_unlock(&bch_register_lock);
 
         pr_info("Caching disabled for %s", bdevname(dc->bdev, buf));
@@ -905,10 +908,10 @@ void bch_cached_dev_detach(struct cached_dev *dc)
 {
         lockdep_assert_held(&bch_register_lock);
 
-        if (atomic_read(&dc->disk.closing))
+        if (test_bit(BCACHE_DEV_CLOSING, &dc->disk.flags))
                 return;
 
-        if (atomic_xchg(&dc->disk.detaching, 1))
+        if (test_and_set_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
                 return;
 
         /*
@@ -1064,11 +1067,7 @@ static void cached_dev_flush(struct closure *cl)
         struct bcache_device *d = &dc->disk;
 
         mutex_lock(&bch_register_lock);
-        d->flush_done = 1;
-
-        if (d->c)
-                bcache_device_unlink(d);
-
+        bcache_device_unlink(d);
         mutex_unlock(&bch_register_lock);
 
         bch_cache_accounting_destroy(&dc->accounting);
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 4b672449ffaf..194d43782ea4 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -370,7 +370,7 @@ STORE(__bch_flash_dev)
         }
 
         if (attr == &sysfs_unregister) {
-                atomic_set(&d->detaching, 1);
+                set_bit(BCACHE_DEV_DETACHING, &d->flags);
                 bcache_device_stop(d);
         }
 
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index 22e21dc9a037..99053b1251be 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -89,7 +89,7 @@ static unsigned writeback_delay(struct cached_dev *dc, unsigned sectors)
 {
         uint64_t ret;
 
-        if (atomic_read(&dc->disk.detaching) ||
+        if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
             !dc->writeback_percent)
                 return 0;
 
@@ -404,7 +404,7 @@ static int bch_writeback_thread(void *arg)
         while (!kthread_should_stop()) {
                 down_write(&dc->writeback_lock);
                 if (!atomic_read(&dc->has_dirty) ||
-                    (!atomic_read(&dc->disk.detaching) &&
+                    (!test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) &&
                      !dc->writeback_running)) {
                         up_write(&dc->writeback_lock);
                         set_current_state(TASK_INTERRUPTIBLE);
@@ -437,7 +437,7 @@ static int bch_writeback_thread(void *arg)
 
                         while (delay &&
                                !kthread_should_stop() &&
-                               !atomic_read(&dc->disk.detaching))
+                               !test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags))
                                 delay = schedule_timeout_interruptible(delay);
                 }
         }
diff --git a/drivers/md/bcache/writeback.h b/drivers/md/bcache/writeback.h
index fe7d9d56492b..c9ddcf4614b9 100644
--- a/drivers/md/bcache/writeback.h
+++ b/drivers/md/bcache/writeback.h
@@ -45,7 +45,7 @@ static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
         unsigned in_use = dc->disk.c->gc_stats.in_use;
 
         if (cache_mode != CACHE_MODE_WRITEBACK ||
-            atomic_read(&dc->disk.detaching) ||
+            test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
             in_use > CUTOFF_WRITEBACK_SYNC)
                 return false;