From 4d1662a30dde6e545086fe0e8fd7e474c4e0b639 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 6 Feb 2014 06:08:56 -0500 Subject: [PATCH] dm thin: avoid metadata commit if a pool's thin devices haven't changed Commit 905e51b ("dm thin: commit outstanding data every second") introduced a periodic commit. This commit occurs regardless of whether any thin devices have made changes. Fix the periodic commit to check if any of a pool's thin devices have changed using dm_pool_changed_this_transaction(). Reported-by: Alexander Larsson Signed-off-by: Mike Snitzer Acked-by: Joe Thornber Cc: stable@vger.kernel.org --- drivers/md/dm-thin-metadata.c | 17 +++++++++++++++++ drivers/md/dm-thin-metadata.h | 2 ++ drivers/md/dm-thin.c | 3 ++- 3 files changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index 7da3476..3bb4506 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -1489,6 +1489,23 @@ bool dm_thin_changed_this_transaction(struct dm_thin_device *td) return r; } +bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd) +{ + bool r = false; + struct dm_thin_device *td, *tmp; + + down_read(&pmd->root_lock); + list_for_each_entry_safe(td, tmp, &pmd->thin_devices, list) { + if (td->changed) { + r = td->changed; + break; + } + } + up_read(&pmd->root_lock); + + return r; +} + bool dm_thin_aborted_changes(struct dm_thin_device *td) { bool r; diff --git a/drivers/md/dm-thin-metadata.h b/drivers/md/dm-thin-metadata.h index 9a36856..dd6088a 100644 --- a/drivers/md/dm-thin-metadata.h +++ b/drivers/md/dm-thin-metadata.h @@ -161,6 +161,8 @@ int dm_thin_remove_block(struct dm_thin_device *td, dm_block_t block); */ bool dm_thin_changed_this_transaction(struct dm_thin_device *td); +bool dm_pool_changed_this_transaction(struct dm_pool_metadata *pmd); + bool dm_thin_aborted_changes(struct dm_thin_device *td); int dm_thin_get_highest_mapped_block(struct dm_thin_device *td, diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c index faaf944..d501e43 100644 --- a/drivers/md/dm-thin.c +++ b/drivers/md/dm-thin.c @@ -1357,7 +1357,8 @@ static void process_deferred_bios(struct pool *pool) bio_list_init(&pool->deferred_flush_bios); spin_unlock_irqrestore(&pool->lock, flags); - if (bio_list_empty(&bios) && !need_commit_due_to_time(pool)) + if (bio_list_empty(&bios) && + !(dm_pool_changed_this_transaction(pool->pmd) && need_commit_due_to_time(pool))) return; if (commit(pool)) { -- 2.7.4