The deferred_set entries should not be incremented until the bio
prison cells are held. Otherwise quiescing a block for discard may
end up waiting for a bio that's held in the discard bios cell.
---
drivers/md/dm-thin.c | 59 +++++++++++++++++++++++++++++++++++++-------------
1 file changed, 44 insertions(+), 15 deletions(-)
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 504f3d6..8e47f44 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -222,10 +222,28 @@ struct thin_c {
struct pool *pool;
struct dm_thin_device *td;
+
+ /*
+ * The cell structures are too big to put on the stack, so we have
+ * a couple here for use by the main mapping function.
+ */
+ spinlock_t lock;
+ struct dm_bio_prison_cell cell1, cell2;
};
/*----------------------------------------------------------------*/
+/*
+ * wake_worker() is used when new work is queued and when pool_resume is
+ * ready to continue deferred IO processing.
+ */
+static void wake_worker(struct pool *pool)
+{
+ queue_work(pool->wq, &pool->worker);
+}
+
+/*----------------------------------------------------------------*/
+
static int bio_detain(struct pool *pool, struct dm_cell_key *key, struct bio *bio,
struct dm_bio_prison_cell **result)
{
@@ -264,6 +282,19 @@ static void cell_release_no_holder(struct pool *pool,
dm_bio_prison_free_cell(pool->prison, cell);
}
+static void cell_defer_no_holder_no_free(struct thin_c *tc,
+ struct dm_bio_prison_cell *cell)
+{
+ struct pool *pool = tc->pool;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pool->lock, flags);
+ dm_cell_release_no_holder(pool->prison, cell, &pool->deferred_bios);
+ spin_unlock_irqrestore(&pool->lock, flags);
+
+ wake_worker(pool);
+}
+
static void cell_error(struct pool *pool,
struct dm_bio_prison_cell *cell)
{
@@ -467,15 +498,6 @@ static void remap_and_issue(struct thin_c *tc, struct bio *bio,
issue(tc, bio);
}
-/*
- * wake_worker() is used when new work is queued and when pool_resume is
- * ready to continue deferred IO processing.
- */
-static void wake_worker(struct pool *pool)
-{
- queue_work(pool->wq, &pool->worker);
-}
-
/*----------------------------------------------------------------*/
/*
@@ -1429,8 +1451,8 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
dm_block_t block = get_bio_block(tc, bio);
struct dm_thin_device *td = tc->td;
struct dm_thin_lookup_result result;
- struct dm_bio_prison_cell *cell1, *cell2;
struct dm_cell_key key;
+ struct dm_bio_prison_cell *cell_result;
thin_hook_bio(tc, bio);
@@ -1470,19 +1492,24 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_SUBMITTED;
}
+ spin_lock(&tc->lock);
build_virtual_key(tc->td, block, &key);
- if (bio_detain(tc->pool, &key, bio, &cell1))
+ if (dm_bio_detain(tc->pool->prison, &key, bio, &tc->cell1, &cell_result)) {
+ spin_unlock(&tc->lock);
return DM_MAPIO_SUBMITTED;
+ }
build_data_key(tc->td, result.block, &key);
- if (bio_detain(tc->pool, &key, bio, &cell2)) {
- cell_defer_no_holder(tc, cell1);
+ if (dm_bio_detain(tc->pool->prison, &key, bio, &tc->cell2, &cell_result)) {
+ cell_defer_no_holder_no_free(tc, &tc->cell1);
+ spin_unlock(&tc->lock);
return DM_MAPIO_SUBMITTED;
}
inc_all_io_entry(tc->pool, bio);
- cell_defer_no_holder(tc, cell2);
- cell_defer_no_holder(tc, cell1);
+ cell_defer_no_holder_no_free(tc, &tc->cell2);
+ cell_defer_no_holder_no_free(tc, &tc->cell1);
+ spin_unlock(&tc->lock);
remap(tc, bio, result.block);
return DM_MAPIO_REMAPPED;
@@ -2638,6 +2665,8 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
if (r)
goto bad_thin_open;
+ spin_lock_init(&tc->lock);
+
ti->num_flush_requests = 1;
ti->flush_supported = true;
ti->per_bio_data_size = sizeof(struct dm_thin_endio_hook);
--
1.7.10.4
--
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