dm thin: eliminate the no_free_space flag

The pool's error_if_no_space flag can easily serve the same purpose that
no_free_space did, namely: control whether handle_unserviceable_bio()
will error a bio or requeue it.

This is cleaner since error_if_no_space is established when the pool's
features are processed during table load.  So it avoids managing the
no_free_space flag by taking the pool's spinlock.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 075c39edea21f04f35e7b04f694ae96073dfc27b..a55c5ebb4031a8e732bec7dcdac5a6a1a45fd6e5 100644 (file)
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -165,7 +165,6 @@ struct pool {
 
        struct pool_features pf;
        bool low_water_triggered:1;     /* A dm event has been sent */
-       bool no_free_space:1;           /* bios will be requeued if set */
 
        struct dm_bio_prison *prison;
        struct dm_kcopyd_client *copier;
@@ -991,10 +990,10 @@ static void handle_unserviceable_bio(struct pool *pool, struct bio *bio)
         */
        WARN_ON_ONCE(get_pool_mode(pool) != PM_READ_ONLY);
 
-       if (pool->no_free_space)
-               retry_on_resume(bio);
-       else
+       if (pool->pf.error_if_no_space)
                bio_io_error(bio);
+       else
+               retry_on_resume(bio);
 }
 
 static void retry_bios_on_resume(struct pool *pool, struct dm_bio_prison_cell *cell)
@@ -1437,18 +1436,6 @@ static void set_pool_mode(struct pool *pool, enum pool_mode mode)
        }
 }
 
-static void set_no_free_space(struct pool *pool)
-{
-       unsigned long flags;
-
-       if (pool->pf.error_if_no_space)
-               return;
-
-       spin_lock_irqsave(&pool->lock, flags);
-       pool->no_free_space = true;
-       spin_unlock_irqrestore(&pool->lock, flags);
-}
-
 /*
  * Rather than calling set_pool_mode directly, use these which describe the
  * reason for mode degradation.
@@ -1457,7 +1444,6 @@ static void out_of_data_space(struct pool *pool)
 {
        DMERR_LIMIT("%s: no free data space available.",
                    dm_device_name(pool->pool_md));
-       set_no_free_space(pool);
        set_pool_mode(pool, PM_READ_ONLY);
 }
 
@@ -1470,11 +1456,9 @@ static void metadata_operation_failed(struct pool *pool, const char *op, int r)
 
        if (r == -ENOSPC &&
            !dm_pool_get_free_metadata_block_count(pool->pmd, &free_blocks) &&
-           !free_blocks) {
+           !free_blocks)
                DMERR_LIMIT("%s: no free metadata space available.",
                            dm_device_name(pool->pool_md));
-               set_no_free_space(pool);
-       }
 
        set_pool_mode(pool, PM_READ_ONLY);
 }
@@ -1819,7 +1803,6 @@ static struct pool *pool_create(struct mapped_device *pool_md,
        INIT_LIST_HEAD(&pool->prepared_mappings);
        INIT_LIST_HEAD(&pool->prepared_discards);
        pool->low_water_triggered = false;
-       pool->no_free_space = false;
        bio_list_init(&pool->retry_on_resume_list);
 
        pool->shared_read_ds = dm_deferred_set_create();
@@ -2346,7 +2329,6 @@ static void pool_resume(struct dm_target *ti)
 
        spin_lock_irqsave(&pool->lock, flags);
        pool->low_water_triggered = false;
-       pool->no_free_space = false;
        __requeue_bios(pool);
        spin_unlock_irqrestore(&pool->lock, flags);