From 50f3c3efdd5773d90396be07a7ecaa58227ff906 Mon Sep 17 00:00:00 2001 From: Joe Thornber Date: Fri, 13 Jun 2014 13:57:09 +0100 Subject: [PATCH] dm thin: switch to an atomic_t for tracking pending new block preparations Previously we used separate boolean values to track quiescing and copying actions. By switching to an atomic_t we can support blocks that need a partial copy and partial zero. Signed-off-by: Joe Thornber Signed-off-by: Mike Snitzer --- drivers/md/dm-thin.c | 29 ++++++++++++++++------------- 1 file changed, 16 insertions(+), 13 deletions(-) diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index fc9c848a60c9..4c9a3b5f4ff1 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -554,11 +554,16 @@ static void remap_and_issue(struct thin_c *tc, struct bio *bio, struct dm_thin_new_mapping { struct list_head list; - bool quiesced:1; - bool prepared:1; bool pass_discard:1; bool definitely_not_shared:1; + /* + * Track quiescing, copying and zeroing preparation actions. When this + * counter hits zero the block is prepared and can be inserted into the + * btree. + */ + atomic_t prepare_actions; + int err; struct thin_c *tc; dm_block_t virt_block; @@ -575,11 +580,11 @@ struct dm_thin_new_mapping { bio_end_io_t *saved_bi_end_io; }; -static void __maybe_add_mapping(struct dm_thin_new_mapping *m) +static void __complete_mapping_preparation(struct dm_thin_new_mapping *m) { struct pool *pool = m->tc->pool; - if (m->quiesced && m->prepared) { + if (atomic_dec_and_test(&m->prepare_actions)) { list_add_tail(&m->list, &pool->prepared_mappings); wake_worker(pool); } @@ -594,8 +599,7 @@ static void copy_complete(int read_err, unsigned long write_err, void *context) m->err = read_err || write_err ? -EIO : 0; spin_lock_irqsave(&pool->lock, flags); - m->prepared = true; - __maybe_add_mapping(m); + __complete_mapping_preparation(m); spin_unlock_irqrestore(&pool->lock, flags); } @@ -609,8 +613,7 @@ static void overwrite_endio(struct bio *bio, int err) m->err = err; spin_lock_irqsave(&pool->lock, flags); - m->prepared = true; - __maybe_add_mapping(m); + __complete_mapping_preparation(m); spin_unlock_irqrestore(&pool->lock, flags); } @@ -836,7 +839,9 @@ static void schedule_copy(struct thin_c *tc, dm_block_t virt_block, m->cell = cell; if (!dm_deferred_set_add_work(pool->shared_read_ds, &m->list)) - m->quiesced = true; + atomic_set(&m->prepare_actions, 1); /* copy only */ + else + atomic_set(&m->prepare_actions, 2); /* quiesce + copy */ /* * IO to pool_dev remaps to the pool target's data_dev. @@ -896,8 +901,7 @@ static void schedule_zero(struct thin_c *tc, dm_block_t virt_block, struct pool *pool = tc->pool; struct dm_thin_new_mapping *m = get_next_mapping(pool); - m->quiesced = true; - m->prepared = false; + atomic_set(&m->prepare_actions, 1); /* no need to quiesce */ m->tc = tc; m->virt_block = virt_block; m->data_block = data_block; @@ -3361,8 +3365,7 @@ static int thin_endio(struct dm_target *ti, struct bio *bio, int err) spin_lock_irqsave(&pool->lock, flags); list_for_each_entry_safe(m, tmp, &work, list) { list_del(&m->list); - m->quiesced = true; - __maybe_add_mapping(m); + __complete_mapping_preparation(m); } spin_unlock_irqrestore(&pool->lock, flags); }