Merge tag 'dm-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper fixes from Mike Snitzer:
"A few dm-thinp fixes for changes merged in 3.15-rc1.
A dm-verity fix for an immutable biovec regression that affects 3.14+.
A dm-cache fix to properly quiesce when using writethrough mode (3.14+)"
* tag 'dm-3.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
dm cache: fix writethrough mode quiescing in cache_map
dm thin: use INIT_WORK_ONSTACK in noflush_work to avoid ODEBUG warning
dm verity: fix biovecs hash calculation regression
dm thin: fix rcu_read_lock being held in code that can sleep
dm thin: irqsave must always be used with the pool->lock spinlock
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 1bf4a71..9380be7 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -2488,6 +2488,7 @@
} else {
inc_hit_counter(cache, bio);
+ pb->all_io_entry = dm_deferred_entry_inc(cache->all_io_ds);
if (bio_data_dir(bio) == WRITE && writethrough_mode(&cache->features) &&
!is_dirty(cache, lookup_result.cblock))
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 53728be..13abade 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -232,6 +232,13 @@
struct bio_list deferred_bio_list;
struct bio_list retry_on_resume_list;
struct rb_root sort_bio_list; /* sorted list of deferred bios */
+
+ /*
+ * Ensures the thin is not destroyed until the worker has finished
+ * iterating the active_thins list.
+ */
+ atomic_t refcount;
+ struct completion can_destroy;
};
/*----------------------------------------------------------------*/
@@ -1486,6 +1493,45 @@
blk_finish_plug(&plug);
}
+static void thin_get(struct thin_c *tc);
+static void thin_put(struct thin_c *tc);
+
+/*
+ * We can't hold rcu_read_lock() around code that can block. So we
+ * find a thin with the rcu lock held; bump a refcount; then drop
+ * the lock.
+ */
+static struct thin_c *get_first_thin(struct pool *pool)
+{
+ struct thin_c *tc = NULL;
+
+ rcu_read_lock();
+ if (!list_empty(&pool->active_thins)) {
+ tc = list_entry_rcu(pool->active_thins.next, struct thin_c, list);
+ thin_get(tc);
+ }
+ rcu_read_unlock();
+
+ return tc;
+}
+
+static struct thin_c *get_next_thin(struct pool *pool, struct thin_c *tc)
+{
+ struct thin_c *old_tc = tc;
+
+ rcu_read_lock();
+ list_for_each_entry_continue_rcu(tc, &pool->active_thins, list) {
+ thin_get(tc);
+ thin_put(old_tc);
+ rcu_read_unlock();
+ return tc;
+ }
+ thin_put(old_tc);
+ rcu_read_unlock();
+
+ return NULL;
+}
+
static void process_deferred_bios(struct pool *pool)
{
unsigned long flags;
@@ -1493,10 +1539,11 @@
struct bio_list bios;
struct thin_c *tc;
- rcu_read_lock();
- list_for_each_entry_rcu(tc, &pool->active_thins, list)
+ tc = get_first_thin(pool);
+ while (tc) {
process_thin_deferred_bios(tc);
- rcu_read_unlock();
+ tc = get_next_thin(pool, tc);
+ }
/*
* If there are any deferred flush bios, we must commit
@@ -1578,7 +1625,7 @@
{
struct noflush_work w;
- INIT_WORK(&w.worker, fn);
+ INIT_WORK_ONSTACK(&w.worker, fn);
w.tc = tc;
atomic_set(&w.complete, 0);
init_waitqueue_head(&w.wait);
@@ -3061,11 +3108,25 @@
/*----------------------------------------------------------------
* Thin target methods
*--------------------------------------------------------------*/
+static void thin_get(struct thin_c *tc)
+{
+ atomic_inc(&tc->refcount);
+}
+
+static void thin_put(struct thin_c *tc)
+{
+ if (atomic_dec_and_test(&tc->refcount))
+ complete(&tc->can_destroy);
+}
+
static void thin_dtr(struct dm_target *ti)
{
struct thin_c *tc = ti->private;
unsigned long flags;
+ thin_put(tc);
+ wait_for_completion(&tc->can_destroy);
+
spin_lock_irqsave(&tc->pool->lock, flags);
list_del_rcu(&tc->list);
spin_unlock_irqrestore(&tc->pool->lock, flags);
@@ -3101,6 +3162,7 @@
struct thin_c *tc;
struct dm_dev *pool_dev, *origin_dev;
struct mapped_device *pool_md;
+ unsigned long flags;
mutex_lock(&dm_thin_pool_table.mutex);
@@ -3191,9 +3253,12 @@
mutex_unlock(&dm_thin_pool_table.mutex);
- spin_lock(&tc->pool->lock);
+ atomic_set(&tc->refcount, 1);
+ init_completion(&tc->can_destroy);
+
+ spin_lock_irqsave(&tc->pool->lock, flags);
list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
- spin_unlock(&tc->pool->lock);
+ spin_unlock_irqrestore(&tc->pool->lock, flags);
/*
* This synchronize_rcu() call is needed here otherwise we risk a
* wake_worker() call finding no bios to process (because the newly
diff --git a/drivers/md/dm-verity.c b/drivers/md/dm-verity.c
index 796007a..7a7bab8 100644
--- a/drivers/md/dm-verity.c
+++ b/drivers/md/dm-verity.c
@@ -330,15 +330,17 @@
return r;
}
}
-
todo = 1 << v->data_dev_block_bits;
- while (io->iter.bi_size) {
+ do {
u8 *page;
+ unsigned len;
struct bio_vec bv = bio_iter_iovec(bio, io->iter);
page = kmap_atomic(bv.bv_page);
- r = crypto_shash_update(desc, page + bv.bv_offset,
- bv.bv_len);
+ len = bv.bv_len;
+ if (likely(len >= todo))
+ len = todo;
+ r = crypto_shash_update(desc, page + bv.bv_offset, len);
kunmap_atomic(page);
if (r < 0) {
@@ -346,8 +348,9 @@
return r;
}
- bio_advance_iter(bio, &io->iter, bv.bv_len);
- }
+ bio_advance_iter(bio, &io->iter, len);
+ todo -= len;
+ } while (todo);
if (!v->version) {
r = crypto_shash_update(desc, v->salt, v->salt_size);
