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dm thin: avoid metadata commit if a pool's thin devices haven't changed

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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 <alexl@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Cc: stable@vger.kernel.org
This commit is contained in:
Mike Snitzer 2014-02-06 06:08:56 -05:00
parent 80ae49aaed
commit 4d1662a30d
3 changed files with 21 additions and 1 deletions
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17
drivers/md/dm-thin-metadata.c
View file

@ -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;

2
drivers/md/dm-thin-metadata.h
View file

@ -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,

3
drivers/md/dm-thin.c
View file

@ -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)) {